Inferior Vena Cava Ultrasonography before General Anesthesia Can Predict Hypotension after Induction

Point-of-care ultrasound in obstetric anesthesia clinical practice

PURPOSE OF THE REVIEW

Point-of-care ultrasound (POCUS) is increasingly recognized as a valuable tool in obstetric anesthesia. This review synthesizes key studies and reviews published within the last 2 years on its application in clinical practice with relevant supporting literature.

RECENT FINDINGS

Handheld ultrasound-assisted neuraxial block placement modestly reduces periprocedure time compared with landmark-based techniques. Devices with integrated three-dimensional or artificial intelligence-guided software may improve first-attempt success, particularly in obese patients. Focused cardiac ultrasound has gained interest as a potential tool for predicting postspinal hypotension through predelivery inferior vena cava collapsibility assessment. POCUS is also valuable for evaluating shock and cardiovascular compromise, aiding in the diagnosis and clinical management of amniotic fluid embolism and maternal cardiomyopathy. Gastric ultrasound can be performed qualitatively, aids aspiration risk assessment, and can be used in studies evaluating drug effects on gastric contents and antral cross-sectional area. Robust training programs are essential to equip obstetric anesthesiologists with sustainable POCUS skill sets.

SUMMARY

POCUS is associated with reduced neuraxial block placement times, provides critical hemodynamic data in patients with amniotic fluid embolism and cardiomyopathy, and allows gastric content evaluation for aspiration risk assessment. Expanding structured training and research is crucial to maximizing its clinical utility.

RESPIRATORY VARIATION OF VELOCITY TIME INTEGRAL AND PEAK VELOCITY OF LEFT VENTRICULAR OUTFLOW TRACT FOR PREDICTING HYPOTENSION AFTER INDUCTION OF GENERAL ANESTHESIA IN ELDERLY PATIENTS

ABSTRACT

Background : Hypotension after induction of general anesthesia may lead to severe complications in elderly patients. This study investigated whether the respiratory variation of velocity time integral (ΔVTI) and peak velocity (ΔVpeak) of left ventricular outflow tract (LVOT) could predict hypotension after induction of general anesthesia in elderly patients. Methods : 120 elderly patients undergoing selective operation under general anesthesia were enrolled in this study. ΔVTI and ΔVpeak of LVOT were measured by transthoracic echocardiography before induction of general anesthesia. After induction, mean arterial pressure (MAP) was recorded every 1 min for 15 min. Hypotension was defined as a decrease of more than 30% in MAP at baseline or MAP below 65 mmHg from the start of induction. Receiver operating characteristic curves with gray zone and multivariate logistic regression analysis were used to assess the ability of ΔVTI and ΔVpeak of LVOT to predict hypotension after induction of general anesthesia. Results : Hypotension occurred in 64 (53.3%) patients after induction of general anesthesia. The area under receiver operating characteristic curves (AUC) for δVpeak of LVOT to predict hypotension after induction of general anesthesia was 0.811, and the optimal cutoff value was 13.1% with a gray zone of 9.9% to 13.8%, including 45.0% of patients. The AUC for ΔVTI of LVOT was 0.890, and the optimal cutoff value was 13.8% with a gray zone of 11.1% to 13.9%, including 25.8% of patients. After adjusting for confounders, ΔVTI (Odds ratio = 2.24) and ΔVpeak (Odds ratio = 2.09) of LVOT were two significant independent predictors of hypotension after induction of general anesthesia. Conclusions : ΔVTI of LVOT was a reliable predictor of hypotension after the induction of general anesthesia in elderly patients. ΔVpeak of LVOT should be used cautiously to predict hypotension after induction of general anesthesia due to nearly half of elderly patients in the gray zone. Trial registration : This study was registered in the Chinese Clinical Trial Registry (registration number: ChiCTR2300077117).

Feasibility of a Machine Learning Classifier for Predicting Post-Induction Hypotension in Non-Cardiac Surgery

PURPOSE

To develop a machine learning (ML) classifier for predicting post-induction hypotension (PIH) in non-cardiac surgeries.

MATERIALS AND METHODS

Preoperative data and early vital signs were obtained from 3669 cases in the VitalDB database, an open-source registry. PIH was defined as sustained mean arterial pressure (MAP) <65 mm Hg within 20 minutes since induction or from induction to incision. Six different ML algorithms were used to create binary classifiers to predict PIH. The primary outcome was the area under the receiver operating characteristic curve (AUROC) of ML classifiers.

RESULTS

A total of 2321 (63.3%) cases exhibited PIH. Among ML classifiers, the random forest regressor and extremely gradient boosting regressor showed the highest AUROC, both recording a value of 0.772. Excluding these models, the light gradient boosting machine regressor showed the second highest AUROC [0.769; 95% confidence interval (CI), 0.767-0.771], followed by the gradient boosting regressor (0.768; 95% CI, 0.763-0.772), AdaBoost regressor (0.752; 95% CI, 0.743-0.761), and automatic relevance determination regression (0.685; 95% CI, 0.669-0.701). The top three important features were mean diastolic blood pressure (DBP), minimum MAP, and minimum DBP from anesthetic induction to tracheal intubation, and these features were lower in cases with PIH (all p<0.001).

CONCLUSION

ML classifiers exhibited moderate performance in predicting PIH, and have the potential for real-time prediction.

Machine learning-based prediction of post-induction hypotension: identifying risk factors and enhancing anesthesia management

BACKGROUND

Post-induction hypotension (PIH) increases surgical complications including myocardial injury, acute kidney injury, delirium, stroke, prolonged hospitalization, and endangerment of the patient's life. Machine learning is an effective tool to analyze large amounts of data and identify perioperative complication factors. This study aims to identify risk factors for PIH and develop predictive models to support anesthesia management.

METHODS

A dataset of 5406 patients was analyzed using machine learning methods. Logistic regression, random forest, XGBoost, and neural network models were compared. Model performance was evaluated using the area under the receiver operating characteristic curve (AUROC), calibration curves, and decision curve analysis (DCA).

RESULTS

The logistic regression model achieved an AUROC of 0.74 (95% CI: 0.71-0.77), outperforming the random forest (AUROC: 0.71), XGBoost (AUROC: 0.72), and neural network (AUROC: 0.72) models. In terms of calibration, logistic regression demonstrated superior performance, as reflected by Brier Scores and calibration curves, followed by XGBoost, random forest, and neural network. Decision curve analysis indicated that the logistic regression model provided the greatest clinical utility among all models. Baseline blood pressure, age, sex, type of surgery, platelet count, and certain anesthesia-inducing drugs were identified as important features.

CONCLUSIONS

This study provides a valuable tool for personalized preoperative risk assessment and customized anesthesia management, allowing for early intervention and improved patient outcomes. Integration of machine learning models into electronic medical record systems can facilitate real-time risk assessment and prediction.

Role of the inferior vena cava collapsibility index in predicting propofol-induced hypotension in patients undergoing colonoscopy

BACKGROUND

Hypotension is a common side effect of propofol induction, and when severe, it is associated with adverse outcomes. Ultrasonography of the inferior vena cava (IVC) is a reliable indicator of the intravascular volume. This study investigated whether preoperative IVC ultrasound measurements could predict hypotension after propofol induction in patients undergoing colonoscopies.

METHODS

Sixty-two adult patients with American Society of Anesthesiologists physical status (ASA) I-II scheduled for colonoscopy after propofol induction were recruited. The Ultrasound Maximum IVC diameter (dIVCmax), minimum IVC diameter (dIVCmin), and collapsibility index (IVC-CI) were assessed in all patients before propofol induction. Mean blood pressure (MBP) was recorded before induction. Propofol was injected intravenously after ultrasound measurements. MBP was recorded 1, 3, 5, and 10 min after propofol induction. The receiver operating characteristic (ROC) curve of IVC-CI was compared with that of patients who developed hypotension after propofol induction.

RESULTS

Sixty-two patients completed the study, and their data were considered for statistical analysis. After induction,30 patients developed hypotension. The area under the curve (95% confidence interval) was 0.72 (0.595 to 0.849) for IVC-CI. The optimal IVC-CI cutoff value was 38.25%, with a sensitivity of 56.7% and specificity of 71.9%. IVC-CI before induction strongly correlated with the maximum percentage of MBP drop after propofol induction. (regression coefficient = 0.33, P = 0.008), respectively.

CONCLUSION

Pre-induction IVC-CI > 38.25% is a non-invasive predictor of propofol-induced hypotension in patients undergoing colonoscopy and is strongly correlated with MBP drop.

TRIAL REGISTRATION

This clinical trial was approved by the Ethics Committee of The Affiliated Lianyungang Hospital of Xuzhou Medical University (YJ-20190529001). All the study procedures were performed in accordance with the ethical standards of the Helsinki Declaration of 2013.

The effect-site concentration of remifentanil blunting endotracheal intubation responses in elderly patients during anesthesia induction with etomidate: a dose-exploration study

PURPOSE

Laryngoscopy and endotracheal intubation are known to increase activity of the sympathetic nervous system, and are usually associated with perioperative hypertension, cardiac arrhythmia, and tachycardia. The aim of this study was to determine the effect-site concentrations of remifentanil to inhibit the tracheal intubation response during etomidate anesthesia in elderly patients.

METHODS

American Society of Anesthesiologists physical status I-III patients aged 65 or older and scheduled for general anesthesia for elective surgery were enrolled in the study. Anesthesia induction was applied with etomidate 0.3 mg/kg, rocuronium 0.6 mg/kg, and target controlled infusion of remifentanil under the Minto pharmacokinetic model. Invasive continuous arterial blood pressure monitoring was used throughout the operation. A positive response was defined if the maximal mean arterial pressure (MAP) or heart rate (HR) within 3 min after tracheal intubation was 20% higher than the baseline value. The Dixon sequential method was used for the test, and the initial effect-site concentrations of remifentanil was 6 ng/ml. The EC50 and EC95 for the suppression of endotracheal intubation response by remifentanil were calculated by the probit method.

RESULTS

The EC50 for inhibiting tracheal intubation response by remifentanil in elderly patients was 6.53 ng/ml (95% CI:6.01-7.05 ng/ml) and EC95 was 8.05 ng/ml (95% CI:7.32-8.78 ng/ml) when combined with etomidate anesthesia. The changes of MAP, HR and BIS in positive group were significantly higher than those of negative group (P < 0.05). There were no episodes of hypoxemia, muscular tremor, chest wall rigidity or choking cough in both groups.

CONCLUSIONS

Target controlled infusion of remifentanil in combination with etomidate is effective preventing hemodynamic instability in elderly patients during the anesthesia induction and endotracheal intubation.

CLINICAL TRIAL REGISTRATION

This article was registered at Chinese Clinical Trial Registry ( www.chictr.org.cn registration number: ChiCTR2300076261, date of registration: 28/09/2023).

Defining Postinduction Hemodynamic Instability With an Automated Classification Model

BACKGROUND

Postinduction hypotension (PIH) may be associated with increased morbidity and mortality. In earlier studies, the definition of PIH is solely based on different absolute or relative thresholds. However, the time-course (eg, how fast blood pressure drops during induction) is rarely incorporated, whereas it might represent the hemodynamic instability of a patient. We propose a comprehensive model to distinguish hemodynamically unstable from stable patients by combining blood pressure thresholds with the magnitude and speed of decline.

METHODS

This prospective study included 375 adult elective noncardiac surgery patients. Noninvasive blood pressure was continuously measured between 5 minutes before up to 15 minutes after the first induction agent had been administered. An expert panel rated whether the patient experienced clinically relevant hemodynamic instability or not. Interrater correlation coefficient and intraclass correlation were computed to check for consistency between experts. Next, an automated classification model for clinically relevant hemodynamic instability was developed using mean, maximum, minimum systolic, mean, diastolic arterial blood pressure (SAP, MAP, and DAP, respectively) and their corresponding time course of decline. The model was trained and tested based on the hemodynamic instability labels provided by the experts.

RESULTS

In total 78 patients were classified as having experienced hemodynamic instability and 279 as not. The hemodynamically unstable patients were significantly older (7 years, 95% confidence interval (CI), 4-11, P < .001), with a higher prevalence of chronic obstructive pulmonary disease (COPD) (3% higher, 95% CI, 1-8, P = .036). Before induction, hemodynamically unstable patients had a higher SAP (median (first-third quartile): 161 (145-175) mm Hg vs 150 (134-166) mm Hg, P < .001) compared to hemodynamic stable patients. Interrater agreement between experts was 0.92 (95% CI, 0.89-0.94). The random forest classifier model showed excellent performance with an area under the receiver operating curve (AUROC) of 0.96, a sensitivity of 0.84, and specificity of 0.94.

CONCLUSIONS

Based on the high sensitivity and specificity, the developed model is able to differentiate between clinically relevant hemodynamic instability and hemodynamic stable patients. This classification model will pave the way for future research concerning hemodynamic instability and its prevention.

Estimating the usefulness of inferior vena cava collapsibility index and caval aorta index to predict hypotension after spinal anaesthesia in adult patients undergoing elective surgery in a tertiary care hospital

Background and Aims

Post-spinal anaesthesia hypotension (PSAH) can occur in 25-75% of patients. The preload or volume status of a patient is an important contributor to PSAH, and coloading with fluids is advocated to prevent PSAH. Instead of blind volume loading, prediction of volume status using inferior vena cava (IVC) collapsibility index (IVCCI) and caval aorta index (IVC: Ao index) may be used to guide fluid administration.

Material and Methods

In our study, we used ultrasound in the immediate pre-operative period to calculate IVCCI and IVC: Ao index in patients scheduled for elective surgery in the supine position, under spinal anaesthesia. Spinal anaesthesia was given in the lateral position with 0.5% hyperbaric bupivacaine. Patients were placed supine thereafter, sensory blockade level was ascertained, and blood pressure (BP) was measured every 2 min for 30 min. Episodes of hypotension were treated with fluids or vasopressors as per the discretion of the treating anaesthesiologist. In the study, 73 patients were screened, out of which 69 were included.

Results

Totally, 23 participants out of 69 developed PSAH. The receiver operating characteristic (ROC) curve was made and the area under the curve analysis was done on our collected data. We found that IVC: Ao index has better sensitivity (0.696 for IVC: Ao index ≤0.810) and specificity (0.717 for IVC: Ao index ≤0.810) than IVCCI (sensitivity 0.522 and specificity 0.630 for IVCCI ≥33.32%) to predict PSAH.

Conclusion

IVC: Ao index is a better predictor of PSAH than IVCCI. Thus, it may be used to predict volume status and guide in coloading with fluids during spinal anaesthesia.

Application of ultrasound-guided inferior vena cava collapsibility measurement in volume assessment for patients undergoing single-shot spinal anesthesia in total hip arthroplasty

To explore the value of ultrasound in volume assessment during the perioperative period of single-shot spinal anesthesia for total hip arthroplasty. A total of 100 patients undergoing elective surgery under spinal anesthesia at our hospital from January 2022 to January 2024 were selected. Transthoracic echocardiography was used to measure the diameter of the abdominal aorta (Ao) before anesthesia (T1), 10 minutes after anesthesia (T2), and 30 minutes after anesthesia (T3). The inferior vena cava collapsibility index (IVC-CI) and the ratio of IVCe to Ao (IVCe/Ao) were calculated. A volume load test was performed 10 minutes after anesthesia. Based on the increase in stroke volume (ΔSV) after the volume load test, patients were divided into a volume-responsive group (ΔSV ≥ 15%) and a volume-nonresponsive group (ΔSV < 15%). The reliability of inferior vena cava parameters in predicting hypotension after spinal anesthesia and the value in predicting volume responsiveness postanesthesia were evaluated using ROC curves. A total of 100 patients were enrolled, 18 were withdrawn, and a total of 82 patients were included. After the volume load test, the parameters of the volume response group and the volume nonresponse group were basically consistent, and the difference was not statistically significant (P > .05). The SV of volume reaction group was significantly higher than that of volume no reaction group (P < .05). The incidence of hypotension in the volume response group was higher than that in the non-volume response group (51.28% vs 11.63%, χ2 = 15.174, P < .01). The AUC for volume reactivity prediction using IVCe, IVCi, IVC-CI, and IVCe/Ao were 0.62, 0.71, 0.70, and 0.72, respectively. IVCi, IVC-CI, and IVCe/Ao were significant predictors of volume reactivity (P < .05). The AUC predicting persistent hypotension after spinal anesthesia using IVCe, IVCi, IVC-CI, and IVCe/Ao were 0.78, 0.79, 0.70, and 0.84, respectively. IVCe, IVCi, IVC-CI, and IVCe/Ao can predict volume reactivity before anesthesia. IVCi, IVC-CI, and IVCe/Ao predicted persistent hypotension in patients with spinal anesthesia after anesthesia, and IVCe/Ao showed the best predictive effect. Thus, IVCe/Ao is a reliable parameter for predicting persistent hypotension and assessing volumetric reactivity.

Efficacy of the inferior vena cava collapsibility index in predicting anaesthesia-induced hypotension in elderly patients undergoing hip arthroplasty

The inferior vena cava collapsibility index (IVCCI) has been used to predict fluid responsiveness. This study aimed to evaluate the accuracy of the perioperative IVCCI to predict postinduction hypotension (PIH) under general anaesthesia (GA) combined with lumbar plexus sacral plexus block (LSPB) in elderly patients undergoing hip arthroplasty. A total of forty patients aged over 65 years were recruited for this prospective observational study. The diameters of the inferior vena cava (IVC), common iliac vein (CIV) and IVCCI were measured at baseline and 15 min post-LSPB. PIH was defined as a systolic blood pressure less than 90 mmHg or a ≥ 30% drop from baseline; patients were divided into hypotensive and nonhypotensive groups. The primary objective of this study was to evaluate the ability of the IVCCI to predict PIH via receiver operating characteristic (ROC) analysis. The secondary objective was to observe the change in CIV diameter. Eighteen patients (45%) developed PIH during GA. No statistically significant differences in baseline or post-LSPB IVCCI were detected between hypotensive and nonhypotensive patients (p > 0.05), whereas a significant expansion of the CIV (0.83 cm to 1.10 cm) was observed 15 min post-LSPB in all patients (p < 0.0001). According to the ROC curve analysis, the IVCCI cannot accurately predict severe PIH: the area under the ROC curve for the IVCCI was 0.54 (95% confidence interval: 0.35-0.72, P = 0.69). Thus, the IVCCI is not an effective predictor of PIH during GA combined with LSPB in elderly patients undergoing hip arthroplasty. Additionally, significant expansion of the CIV was observed 15 min after LSPB, indicating sympathetic blockade of the unilateral lower extremity.

Comparing preoperative fasting and ultrasound-measured intravascular volume status in elective surgery, enhanced recovery patients versus inpatient, urgent surgery patients and the ability of IVC collapsibility to predict post-induction hypotension

Hypotension following induction of general anaesthesia has been shown to result in increased complications and mortality postoperatively. Patients admitted to the hospital undergoing urgent surgery are often fasted from fluids for significant periods compared to elective patients subject to Enhanced Recovery After Surgery protocols despite guidelines stating that a two-hour fast is sufficient. The aim of this prospective, observational study was to compare fasting times and intravascular volume status between elective surgery patients subject to enhanced recovery protocols and inpatient, urgent surgery patients and to assess differences in the incidence of post-induction hypotension. Fasting data was obtained by questionnaire in the preoperative area in addition to inferior vena cava collapsibility index, a non-invasive measure of intravascular volume. Blood pressure readings and drug administration for the ten minutes following induction were obtained from patients' charts. Inpatients undergoing urgent surgery were fasted significantly longer than enhanced recovery patients and had lower intravascular volume. However, no difference was found in the incidence of post-induction hypotension.

Inferior vena cava collapsibility index for predicting hypotension after spinal anesthesia in patients undergoing total knee arthroplasty

OBJECTIVE

This study aimed to identify risk factors associated with hypotension in patients undergoing total knee arthroplasty (TKA) under spinal anesthesia.

METHOD

A total of 200 patients (50-75 years of age) who underwent elective TKA under spinal anesthesia between October 2023 and January 2024 were enrolled. Patients were divided into two groups (hypotensive and nonhypotensive) depending on the occurrence of postspinal anesthesia hypotension (PSAH). Patient characteristics (age, sex, body mass index, and medical history), blood pressure, heart rate, and ultrasound data before anesthesia were documented. Multivariate logistic regression models were used to determine risk factors for hypotension after spinal anesthesia. Furthermore, a nomogram was constructed according to independent predictive factors. The area under the curve (AUC) and calibration curves were employed to assess the performance of the nomogram.

RESULTS

In total, 175 patients were analyzed and 79 (45.1%) developed PSAH. Logistic regression analysis revealed that variability of the inferior vena cava (odds ratio, OR, 1.147; 95% confidence interval, CI: 1.090-1.207; p < 0.001) and systolic arterial blood pressure (SABP, OR 1.078; 95% CI: 1.043-1.115; p < 0.001) were independent risk factors for PSAH. Receiver operating characteristic (ROC) curve analysis showed that the AUC of the inferior vena cava collapsibility index (IVCCI) and SABP alone were 0.806 and 0.701, respectively, while the AUC of both combined was 0.841. Specifically, an IVCCI of > 37.5% and systolic arterial blood pressure of > 157 mm Hg were considered threshold values. Furthermore, we found that the combination had a better predictive value with higher AUC value, sensitivity, and specificity than the index alone. The nomogram model and calibration curves demonstrated the satisfactory predictive performance of the model.

CONCLUSION

Elevated preoperative systolic arterial blood pressure and a higher IVCCI were identified as independent risk factors for hypotension in patients receiving spinal anesthesia, which may help guide personalized treatment.

Diagnostic accuracy of subclavian vein versus inferior vena cava collapsibility index for predicting postinduction hypotension: An observational study

Background

Hypotension following induction of general anesthesia (GA) is commonly observed. Ultrasound (US) measurement of collapsibility index (CI) of the inferior vena cava (IVC) for predicting postinduction hypotension has been studied. As there is limited data available comparing the diagnostic accuracy of subclavian vein (SCV) versus IVC-CI, we performed this observational study.

Methods

A total of 132 adult patients scheduled for elective surgery under GA were enrolled. US measurements of three readings of maximum and minimum diameters of SCV and IVC were recorded during both quiet and deep breathing, and the mean of three values was calculated. CI was derived using the formula: (dmax - dmin) × 100/dmax. Subsequently, GA was administered using standard technique, irrespective of the findings of SCV and IVC measurements. The administered drugs and dosage were recorded. Hemodynamic parameters were collected at baseline and then at every minute for the first 20 min. The primary objective was to compare the diagnostic accuracies of SCV-CI and IVC-CI for prediction of postinduction hypotension during quiet breathing. The secondary objectives were to compare the diagnostic accuracies during deep breathing and find the correlation between IVC-CI and SC-CI during quiet and deep breathing, incidence of hypotension, and time required to acquire US images.

Results

Fifty-seven patients developed postinduction hypotension. During quiet breathing, SCV-CI ≥10% had a sensitivity of 68% and specificity of 56% (area under curve [AUC] [95% confidence interval {CI}] of 0.659 [0.56-0.75]; P = 0.002), while IVC-CI ≥34% had a sensitivity of 70% and specificity of 59% (AUC [95% CI] of 0.672 [0.58-0.76]; P = 0.001) for prediction of postinduction hypotension. During deep breathing, both SCV-CI and IVC-CI had moderate accuracy (P = 0.001 for both). Pearson's correlation showed a significant positive correlation between SCV-CI and IVC-CI with a correlation coefficient (r) of 0.313 during quiet breathing and 0.379 during deep breathing (P < 0.001). The time required for acquiring US images was significantly less for SCV compared to IVC during both quiet and deep breathing (P < 0.001 for both).

Conclusion

Both SCV-CI and IVC-CI were found to have good and comparable diagnostic accuracy for the prediction of postinduction hypotension. We also found a significant positive correlation between SCV-CI and IVC-CI. In comparison to IVC, US scanning of SCV took lesser time to acquire the images.

Prevention of hypotension after induction of general anesthesia using point-of-care ultrasound to guide fluid management: a randomized controlled trial

PURPOSE

Hypotension after induction of general anesthesia (GAIH) is common and is associated with postoperative complications including increased mortality. Collapsibility of the inferior vena cava (IVC) has good performance in predicting GAIH; however, there is limited evidence whether a preoperative fluid bolus in patients with a collapsible IVC can prevent this drop in blood pressure.

METHODS

We conducted a single-centre randomized controlled trial with adult patients scheduled to undergo elective noncardiac surgery under general anesthesia (GA). Patients underwent a preoperative point-of-care ultrasound scan (POCUS) to identify those with a collapsible IVC (IVC collapsibility index ≥ 43%). Individuals with a collapsible IVC were randomized to receive a preoperative 500 mL fluid bolus or routine care (control group). Surgical and anesthesia teams were blinded to the results of the scan and group allocation. Hypotension after induction of GA was defined as the use of vasopressors/inotropes or a decrease in mean arterial pressure < 65 mm Hg or > 25% from baseline within 20 min of induction of GA.

RESULTS

Forty patients (20 in each group) were included. The rate of hypotension after induction of GA was significantly reduced in those receiving preoperative fluids (9/20, 45% vs 17/20, 85%; relative risk, 0.53; 95% confidence interval, 0.32 to 0.89; P = 0.02). The mean (standard deviation) time to complete POCUS was 4 (2) min, and the duration of fluid bolus administration was 14 (5) min. Neither surgical delays nor adverse events occurred as a result of the study intervention.

CONCLUSION

A preoperative fluid bolus in patients with a collapsible IVC reduced the incidence of GAIH without associated adverse effects.

STUDY REGISTRATION

ClinicalTrials.gov (NCT05424510); first submitted 15 June 2022.

Inferior vena cava ultrasound to predict hypotension after general anesthesia induction: a systematic review and meta-analysis of observational studies

PURPOSE

Hypotension after induction of general anesthesia is common and is associated with significant adverse events. Identification of patients at high risk can inform the use of preoperative mitigation strategies. We conducted a systematic review and meta-analysis to assess the diagnostic accuracy of the inferior vena cava collapsibility index (IVC-CI) and maximal diameter (dIVCmax) in predicting postinduction hypotension and to identify their predictive performance across different threshold ranges.

METHODS

We searched MEDLINE, PubMed®, and Embase from inception to March 2023 for prospective observational studies exploring the performance of IVC-CI and dIVCmax in predicting postinduction hypotension in adults presenting for elective surgery under general anesthesia. We excluded studies reporting on IVC parameters predicting postinduction hypotension in the obstetric patient population or exclusively in patients with obesity. Trials screening and data extraction were conducted independently. We performed meta-analyses to identify the performance of IVC parameters in predicting postinduction hypotension, followed by subgroup analyses that sought the IVC-CI range with the highest hierarchical summary receiver-operating characteristic area under the curve (HSROC-AUC). We used a bivariate random effects model to calculate summary estimates. We evaluated study quality using Newcastle-Ottawa scores and certainty of evidence using the GRADE framework.

RESULTS

We included 14 studies involving 1,166 patients. Pooled sensitivity and specificity of the IVC-CI to predict postinduction hypotension was 0.68 (95% confidence interval [CI], 0.55 to 0.79; coverage probability, 0.91) and 0.78 (95% CI, 0.69 to 0.85; coverage probability, 0.9), respectively, with an HSROC-AUC of 0.80 (95% CI, 0.68 to 0.85, high quality of evidence). An IVC-CI threshold range of 40-45% had an HSROC-AUC of 0.86 (95% CI, 0.69 to 0.93, high quality of evidence).

CONCLUSIONS

Preoperative IVC-CI is a strong predictor of postinduction hypotension. We recommend that future studies use an IVC-CI threshold of 40-45% (low certainty of evidence). Future studies are needed to establish whether ultrasound-guided preoperative optimization improves outcomes in high-risk patients.

STUDY REGISTRATION

PROSPERO ( CRD42022316140 ); first submitted 10 March 2022.

Preoperative Ultrasound for the Prediction of Postinduction Hypotension: A Systematic Review and Meta-Analysis

Postinduction hypotension (PIH) is closely associated with postoperative adverse outcomes. Preoperative hypovolemia is a key risk factor, and many parameters are available from ultrasound to detect hypovolemia, but the accuracy of PIH from ultrasound remains unclear. This systematic review and meta-analysis aimed to evaluate the commonly used measurements from ultrasound to predict PIH. We searched the PubMed, Cochrane Library, Embase, CNKI, and Web of Science databases from their inception to December 2023. Thirty-six studies were included for quantitative analysis. The pooled sensitivities for the inferior vena cava collapsibility index (IVC-CI), maximum inferior vena cava diameter (DIVCmax), minimum inferior vena cava diameter (DIVCmin), and carotid artery corrected flow time (FTc) were 0.73 (95% CI = 0.65, 0.79), 0.66 (95% CI = 0.54, 0.77), 0.74 (95% CI = 0.60, 0.85), and 0.81 (95% CI = 0.72, 0.88). The pooled specificities for the IVC-CI, DIVCmax, DIVCmin, and carotid artery FTc were 0.82 (95% CI = 0.75, 0.87), 0.75 (95% CI = 0.66, 0.82), 0.76 (95% CI = 0.65, 0.84), and 0.87 (95% CI = 0.77, 0.93). The AUC for the IVC-CI, DIVCmax, DIVCmin, and carotid artery FTc were 0.84 (95% CI = 0.81, 0.87), 0.77 (95% CI = 0.73, 0.81), 0.82 (95% CI = 0.78, 0.85), and 0.91 (95% CI = 0.88, 0.93). Our study demonstrated that ultrasound indices are reliable predictors for PIH. The carotid artery FTc is probably the optimal ultrasound measurement for identifying patients who will develop PIH in our study.

Effect of Fluid Therapy in Early Morning on the Incidence of Post-Induction Hypotension During Non-Cardiac Surgery After Noon: A Single-Center Retrospective Study

Purpose

Post-induction hypotension (PIH) is a common clinical phenomenon linked to increased morbidity and mortality in various non-cardiac surgeries. Patients with surgery in the afternoon may have preoperative hypovolemia caused by prolonged fasting and dehydration, which increases the risk of hypotension during the induction period. However, studies on the fluid therapy in early morning combating PIH remain inadequate. Therefore, we aimed to investigate the influence of prophylactic high-volume fluid in the early morning of the operation day on the incidence of PIH during non-cardiac surgery after noon.

Patients and Methods

We reviewed the medical records of patients who underwent non-cardiac surgery after noon between October 2021 and October 2022. The patients were divided into two groups based on whether they received a substantial volume of intravenous fluid (high-volume group) or not (low-volume group) in the early morning of the surgery day. We investigated the incidence of PIH and intraoperative hypotension (IOH) as well as the accumulated duration of PIH in the first 15 minutes. In total, 550 patients were included in the analysis.

Results

After propensity score matching, the incidence of PIH was 39.7% in the high-volume group and 54.1% in the low-volume group. Multivariate logistic regression analysis showed that patients in the high-volume group had lower incidence of hypotension after induction compared with the low-volume group (odds ratio, 0.55; 95% CI, 0.34-0.89; p = 0.016). The high-volume fluid infusion in the preoperative morning was significantly correlated with the decreased duration of PIH (p = 0.013), but no statistical difference was observed for the occurrence of IOH between the two groups (p = 0.075).

Conclusion

The fluid therapy of more than or equal to 1000 mL in the early morning of the surgery day was associated with a decreased incidence of PIH compared with the low-volume group in patients undergoing non-cardiac surgery after noon.

Effect of subclavian vein diameter combined with perioperative fluid therapy on preventing post-induction hypotension in patients with ASA status I or II

BACKGROUND

Perioperative hypotension is frequently observed following the initiation of general anesthesia administration, often associated with adverse outcomes. This study assessed the effect of subclavian vein (SCV) diameter combined with perioperative fluid therapy on preventing post-induction hypotension (PIH) in patients with lower ASA status.

METHODS

This two-part study included patients aged 18 to 65 years, classified as ASA physical status I or II, and scheduled for elective surgery. The first part (Part I) included 146 adult patients, where maximum SCV diameter (dSCVmax), minimum SCV diameter (dSCVmin), SCV collapsibility index (SCVCI) and SCV variability (SCVvariability) assessed using ultrasound. PIH was determined by reduction in mean arterial pressure (MAP) exceeding 30% from baseline measurement or any instance of MAP < falling below 65 mmHg for ≥ a duration of at least 1 min during the period from induction to 10 min after intubation. Receiver Operating Characteristic (ROC) curve analysis was employed to determine the predictive values of subclavian vein diameter and other relevant parameters. The second part comprised 124 adult patients, where patients with SCV diameter above the optimal cutoff value, as determined in Part I study, received 6 ml/kg of colloid solution within 20 min before induction. The study evaluated the impact of subclavian vein diameter combined with perioperative fluid therapy by comparing the observed incidence of PIH after induction of anesthesia.

RESULTS

The areas under the curves (with 95% confidence intervals) for SCVCI and SCVvariability were both 0.819 (0.744-0.893). The optimal cutoff values were determined to be 45.4% and 14.7% (with sensitivity of 76.1% and specificity of 86.7%), respectively. Logistic regression analysis, after adjusting for confounding factors, demonstrated that both SCVCI and SCVvariability were significant predictors of PIH. A threshold of 45.4% for SCVCI was chosen as the grouping criterion. The incidence of PIH in patients receiving fluid therapy was significantly lower in the SCVCI ≥ 45.4% group compared to the SCVCI < 45.4% group.

CONCLUSIONS

Both SCVCI and SCVvariability are noninvasive parameters capable of predicting PIH, and their combination with perioperative fluid therapy can reduce the incidence of PIH.

Diagnostic accuracy of left ventricular outflow tract velocity time integral versus inferior vena cava collapsibility index in predicting post-induction hypotension during general anesthesia: an observational study

BACKGROUND

Point of care ultrasound (POCUS) is being explored for dynamic measurements like inferior vena cava collapsibility index (IVC-CI) and left ventricular outflow tract velocity time integral (LVOT-VTI) to guide anesthesiologists in predicting fluid responsiveness in the preoperative period and in treating post-induction hypotension (PIH) with varying accuracy.

METHODS

In this prospective, observational study on included 100 adult patients undergoing elective surgery under general anesthesia, the LVOT-VTI and IVC-CI measurements were performed in the preoperative room 15 minutes prior to surgery, and PIH was measured for 20 minutes in the post-induction period.

RESULTS

The incidence of PIH was 24%. The area under the curve, sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of the two techniques at 95% confidence interval was 0.613, 30.4%, 93.3%, 58.3%, 81.4%, 73.6% for IVC-CI and 0.853, 83.3%, 80.3%, 57.1%, 93.8%, 77.4% for LVOT-VTI, respectively. In multivariate analysis, the cutoff value for IVC-CI was >51.5 and for LVOT-VTI it was ≤17.45 for predicting PIH with odd ratio [OR] of 8.491 (P=0.025) for IVCCI and OR of 17.427 (P<0.001) for LVOT. LVOT-VTI assessment was possible in all the patients, while 10% of patients were having poor window for IVC measurements.

CONCLUSIONS

We recommend the use of POCUS using LVOT-VTI or IVC-CI to predict PIH, to decrease the morbidity of patients undergoing surgery. Out of these, we recommend LVOT-VTI measurements as it has showed a better diagnostic accuracy (77.4%) with no failure rate.

Effect of carotid corrected flow time combined with perioperative fluid therapy on preventing hypotension after general anesthesia induction in elderly patients: a prospective cohort study

BACKGROUND

Hypotension often occurs following the induction of general anesthesia in elderly patients undergoing surgery and can lead to severe complications. This study assessed the effect of carotid corrected flow time (FTc) combined with perioperative fluid therapy on preventing hypotension after general anesthesia induction in elderly patients.

MATERIALS AND METHODS

The prospective cohort study was divided into two parts. The first part (Part I) consisted of 112 elderly patients. Carotid FTc was measured using Color Doppler Ultrasound 5 min before anesthesia induction. Hypotension was defined as a decrease of greater than 30% in systolic blood pressure (SBP) or a decrease of greater than 20% in mean arterial pressure (MAP) from baseline, or an absolute SBP below 90 mmHg and MAP below 60 mmHg within 3 min after induction of general anesthesia. The predictive value of carotid FTc was determined using receiver operating characteristic (ROC) curve. The second part (Part II) consisted of 65 elderly patients. Based on the results in Part I, elderly patients with carotid FTc below the optimal cut-off value received perioperative fluid therapy at a volume of 8 ml/kg of balanced crystalloids (lactated Ringer's solution) in 30 min before induction. The effect of carotid FTc combined with perioperative fluid therapy was assessed by comparing observed incidence of hypotension after induction.

RESULTS

The area under the ROC for carotid FTc to predict hypotension after induction was 0.876 [95% confidence interval (CI) 0.800-0.952, P <0.001]. The optimal cut-off value was 334.95 ms (sensitivity of 87.20%; specificity of 82.20%). The logistic regression analysis revealed that carotid FTc is an independent predictor for post-induction hypotension in elderly patients. The incidence of post-induction hypotension was significantly lower ( P <0.001) in patients with carotid FTc less than 334.95 ms who received perioperative fluid therapy (35.71%) compared to those who did not (92.31%).

CONCLUSIONS

Carotid FTc combined with the perioperative fluid therapy could significantly reduce the incidence of hypotension after the induction of general anesthesia in elderly patients.

Carotid blood flow changes following a simulated end-inspiratory occlusion maneuver measured by ultrasound can predict hypotension after the induction of general anesthesia: an observational study

BACKGROUND

The primary purpose of this study was to investigate the predictive value of alterations in cervical artery hemodynamic parameters induced by a simulated end-inspiratory occlusion test (sEIOT) measured by ultrasound for predicting postinduction hypotension (PIH) during general anesthesia.

METHODS

Patients undergoing gastrointestinal tumor resection under general anesthesia were selected for this study. Ultrasound has been utilized to assess hemodynamic parameters in carotid artery blood flow before induction, specifically focusing on variations in corrected flow time (ΔFTc) and peak blood flow velocity (ΔCDPV), both before and after sEIOT. Anesthesia was induced by midazolam, sufentanil, propofol, and rocuronium, and blood pressure (BP) and heart rate (HR) were recorded within the first 10 min following endotracheal intubation. PIH was defined as fall in systolic blood pressure (SBP) or mean arterial pressure (MAP) by > 30% of baseline or MAP to < 60 mm Hg.

RESULTS

The area under the receiver operating characteristic curves (AUC) for carotid artery ΔFTc was 0.88 (95%CI, 0.81 to 0.96; P < 0.001), and the optimal cutoff value was -16.57%, with a sensitivity of 91.4% and specificity of 77.60%. The gray zone for carotid artery ΔFTc was -16.34% to -15.36% and included 14% of the patients. The AUC for ΔCDPV was 0.54, with an optimal cutoff value of -1.47%. The sensitivity and specificity were calculated as 55.20% and 57.10%, respectively.

CONCLUSION

The corrected blood flow time changes in the carotid artery induced by sEIOT can predict hypotension following general anesthesia-induced hypotension, wherein ΔFTc less than 16.57% is the threshold.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ( www.chictr.org.cn ; 20/06/2023; ChiCTR2300072632).

The diagnostic accuracy of preoperative perfusion index as a predictor of postspinal anesthesia hypotension in parturients undergoing cesarean delivery: A prospective non-blinded observational study

BACKGROUND AND OBJECTIVES

Spinal anesthesia is the technique of choice for elective cesarean section with a prominent side effect of postspinal anesthesia hypotension (PSH). This needs an early prediction to avoid feto-maternal complication. This study aimed to assess the diagnostic accuracy of perfusion index (PI) and inferior vena cava collapsibility index (IVCCI) in the prediction of PSH.

MATERIAL AND METHODS

Thirty parturients of American Society of Anesthesiologists Physical Status (ASA-PS) 1 and two undergoing cesarean delivery participated in the study. IVCCI, PI, baseline systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP), and heart rate (HR) were noted in the preoperative period. The fall of MBP by 20% from baseline or below 65 mm Hg was considered PSH. After spinal anesthesia, SBP, DBP, MBP, and HR were noted again for diagnosing PSH.

RESULTS

It did not show any statistical difference when comparing the PI between the PSH and non-PSH groups in both the PSH definition groups. IVCCI was significantly higher when PSH was considered MBP <65 mm Hg (P = 0.01). However, IVCCI was found to be statistically insignificant if PSH was considered a 20% reduction in baseline MBP. The correlation matrix between IVCCI and PI showed Pearson's r-value of 0.525, indicating a substantial relationship between the two (P = 0.003). Multivariate logistic regression analysis had shown that neither IVCCI nor PI was a good predictor of PSH in parturients for both definition groups for PSH.

CONCLUSION

Although there is a modest correlation between PI and IVCCI, both cannot be used to predict postspinal hypotension in parturients undergoing elective lower-segment cesarean section (LSCS).

Inferior vena cava collapsibility index as a predictor of hypotension after induction of general anesthesia in hypertensive patients

BACKGROUND

Hypertensive patients are more susceptible to develop hypotension after the induction of general anesthesia (GA), most likely due to hypovolemia. An inferior vena cava collapsibility index (IVCCI) > 40-50% can predict hypotension after the induction of GA in the general population by variable accuracies. The current study aimed to investigate IVCCI% as a predictor of postinduction hypotension in hypertensive patients undergoing noncardiac surgery.

METHODS

Ultrasound IVCCI % was assessed for all controlled hypertensive patients immediately before induction of GA. After induction of GA, patients were diagnosed with postinduction hypotension if their systolic arterial pressure (SAP) dropped by ≥ 30% of the baseline value and/or mean arterial pressure (MAP) dropped to < 65 mmHg up to 15 min after intubation. The receiver operating characteristic (ROC) curve of IVCCI% was compared to patients' classification either developing hypotension after induction of GA or not as a gold standard.

RESULTS

Of the 153 patients who completed the study, 62 (40.5%) developed hypotension after the induction of GA, and 91 (59.5%) did not. An IVCCI > 39% predicted the occurrence of postinduction hypotension with high accuracy (84%) (AUC 0.908, P < 0.001). The area of uncertainty (by gray zone analysis) of IVCCI lies at values from 39 to 45%. This gray zone included 21 patients (13.7% of all patients).

CONCLUSION

An inferior vena cava collapsibility index > 39% before anesthetic induction can be a simple noninvasive reliable predictor of hypotension after the induction of GA for hypertensive patients not treated with angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) and undergoing noncardiac surgery.

TRIAL REGISTRATION

This clinical trial was approved by the Institutional Review Board (IRB) at Zagazig University (ZUIRB #9424 dated 03/04/2022), and patients' informed consent for participation in the study was obtained during the period from May 2022 to May 2023. All study procedures were carried out in accordance with the ethical standards of the Helsinki Declaration of 2013.

Inferior vena cava ultrasound and other techniques for assessment of intravascular and extravascular volume: an update

Goals of volume management are to accurately assess intravascular and extravascular volume and predict response to volume administration, vasopressor support or volume removal. Data are reviewed that support the following: (i) Dynamic parameters reliably guide volume administration and may improve clinical outcomes compared with static parameters, but some are invasive or only validated with mechanical ventilation without spontaneous breathing. (ii) Ultrasound visualization of inferior vena cava (IVC) diameter variations with respiration reliably assesses intravascular volume and predicts volume responsiveness. (iii) Although physiology of IVC respiratory variations differs with mechanical ventilation and spontaneous breathing, the IVC collapsibility index (CI) and distensibility index are interconvertible. (iv) Prediction of volume responsiveness by IVC CI is comparable for mechanical ventilation and spontaneous breathing patients. (v) Respiratory variations of subclavian/proximal axillary and internal jugular veins by ultrasound are alternative sites, with comparable reliability. (vi) Data support clinical applicability of IVC CI to predict hypotension with anesthesia, guide ultrafiltration goals, predict dry weight, predict intra-dialytic hypotension and assess acute decompensated heart failure. (vii) IVC ultrasound may complement ultrasound of heart and lungs, and abdominal organs for venous congestion, for assessing and managing volume overload and deresuscitation, renal failure and shock. (viii) IVC ultrasound has limitations including inadequate visualization. Ultrasound data should always be interpreted in clinical context. Additional studies are required to further assess and validate the role of bedside ultrasonography in clinical care.

Association of infraclavicular axillary vein diameter and collapsibility index with general anesthesia-induced hypotension in elderly patients undergoing gastrointestinal surgery: an observational study

BACKGROUND

The collapse index of inferior Vena Cava (IVC) and its diameter are important predictive tools for fluid responsiveness in patients, especially critically ones. The collapsibility of infraclavicular axillary vein (AXV) can be used as an alternative to the collapsibility of IVC (IVC-CI) to assess the patient's blood volume.

METHODS

A total of 188 elderly patients aged between 65 and 85 years were recruited for gastrointestinal surgery under general anesthesia. Ultrasound measurements AXV and IVC were performed before induction of general anesthesia. Patients were grouped in accordance to the hypotension after induction. ROC curves were used to analyze the predictive value of ultrasound measurements of AXV and IVC for hypotension after induction of anesthesia. Pearson linear correlation was used to assess the correlation of ultrasound measurements and decrease in mean arterial blood pressure (MAP).

RESULTS

The maximum diameter of AXV(dAXVmax) and the maximum diameter of IVC (dIVCmax) were not related to the percentage decrease in MAP; the collapsibility of AXV (AXV-CI) and IVC-CI were positively correlated with MAP changes (correlation coefficients:0.475, 0.577, respectively, p < 0.001). The areas under the curve (AUC) was 0.824 (0.759-0.889) for AXV-CI, and 0.874 (0.820-0.928) for IVC-CI. The optimal threshold for AXV-CI was 31.25% (sensitivity 71.7%, specificity 90.1%), while for IVC-CI was 36.60% (sensitivity 85.9%, specificity 79.0%). Hypotension and down-regulation of MAP during induction can be accurately predicted by AXV-Cl after correction for confounding variables.

CONCLUSION

Infraclavicular axillary vein diameter has no significant correlation with postanesthesia hypotension, whereas AXV-CI may predict postanesthesia hypotension during gastrointestinal surgery of the elderly.

TRIAL REGISTRATION

This study was registered in the Clinical Trial Registry of China on 05/06/2022 (ChiCTR2200060596).

Protocol for development and validation of a prediction model for post-induction hypotension in elderly patients undergoing non-cardiac surgery: a prospective cohort study

INTRODUCTION

Post-induction hypotension (PIH) is a common event in elderly surgical patients and is associated with increased postoperative morbidity and mortality. This study aims to develop and validate a PIH prediction model for elderly patients undergoing elective non-cardiac surgery to identify potential PIH in advance and help to take preventive measures.

METHODS AND ANALYSIS

A total of 938 elderly surgical patients (n=657 for development and internal validation, n=281 for temporal validation) will be continuously recruited at The First Affiliated Hospital of Soochow University in Suzhou, China. The main outcome is PIH during the first 15 min after anaesthesia induction or before skin incision (whichever occurs first). We select candidate predictors based on published literature, professional knowledge and clinical expertise. For model development, we will use the least absolute shrinkage and selection operator regression analysis and multivariable logistic regression. For internal validation, we will apply the bootstrapping technique. After model development and internal validation, temporal validation will be conducted in patients recruited in another time period. We will use the discrimination, calibration and max-rescaled Brier score in the temporal validation cohort. Furthermore, the clinical utility of the prediction model will be assessed using the decision curve analysis, and the results will be presented in a nomogram and a web-based risk calculator.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Ethics Committee of the First Affiliated Hospital of Soochow University (Approval No. 2023-012). This PIH risk prediction model will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ChiCTR2200066201.

Role of Inferior Vena Cava Collapsibility Index in the Prediction of Hypotension Associated With Central Neuraxial Block: A Prospective Observational Study

BACKGROUND

There are only a few studies on perioperative use of inferior vena cava collapsibility index (IVCCI) to predict hypotension after anesthesia. The study aimed to evaluate IVCCI as predictor of hypotension in patients receiving central neuraxial block (CNB) for elective surgery.

METHOD

One hundred patients of ASA grade I/II, aged 18-60 years undergoing elective surgery under CNB were enrolled. Ultrasound IVC examination was performed preoperatively and the patients were allocated to Group C (Collapsing group: IVCCI ≥50%) or Group NC (Non-Collapsing group: IVCCI <50%). Thereafter, in the operation theatre, the patient was given CNB and observed for development of hypotension. The hypotension was treated with additional fluid bolus (5 mL kg-1 over 10 minutes) and/or vasopressor (mephentramine 6 mg IV). The primary objective was to compare the incidence of hypotension; the secondary objective was to compare the fluid and vasopressor requirement in the Groups C and NC.

RESULT

Six patients were excluded from study due to poor visualization of IVC. The mean IVCCI for Group C (n = 53) was 56.06 ± 4.62% and Group NC (n = 41) was 34.01 ± 8.94%. The incidence of hypotension was 56.60% (20/53) in Group C and 4.87% (2/41) in Group NC (P < .001). The vasopressor and fluid requirement was also statistically significantly higher in Group C compared with Group NC (P < .001).

CONCLUSION

Preoperative ultrasound assessment of IVCCI is useful in predicting hypotension after CNB in patients receiving CNB for elective surgery.

Subclavian vein ultrasound-guided fluid management to prevent post-spinal anesthetic hypotension during cesarean delivery: a randomized controlled trial

BACKGROUND

Hypotension frequently occurs after spinal anesthesia during cesarean delivery, and fluid loading is recommended for its prevention. We evaluated the efficacy of subclavian vein (SCV) ultrasound (US)-guided volume optimization in preventing hypotension after spinal anesthesia during cesarean delivery.

METHODS

This randomized controlled study included 80 consecutive full-term parturients scheduled for cesarean delivery under spinal anesthesia. The women were randomly divided into the SCVUS group, with SCVUS analysis before spinal anesthesia with SCVUS-guided volume management, and the control group without SCVUS assessment. The SCVUS group received 3 mL/kg crystalloid fluid challenges repeatedly within 3 min with a 1-min interval based on the SCV collapsibility index (SCVCI), while the control group received a fixed dose (10 mL/kg). Incidence of post-spinal anesthetic hypotension was the primary outcome. Total fluid volume, vasopressor dosage, changes in hemodynamic parameters, maternal adverse effects, and neonatal status were secondary outcomes.

RESULTS

The total fluid volume was significantly higher in the control group than in the SCVUS group (690 [650-757.5] vs. 160 [80-360] mL, p < 0.001), while the phenylephrine dose (0 [0-40] vs. 0 [0-30] µg, p = 0.276) and incidence of post-spinal anesthetic hypotension (65% vs. 60%, p = 0.950) were comparable between both the groups. The incidence of maternal adverse effects, including nausea/vomiting and bradycardia (12.5% vs. 17.5%, p = 0.531 and 7.5% vs. 5%, p = 1.00, respectively), and neonatal outcomes (Apgar scores) were comparable between the groups. SCVCI correlated with the amount of fluid administered (R = 0.885, p < 0.001).

CONCLUSIONS

SCVUS-guided volume management did not ameliorate post-spinal anesthetic hypotension but reduced the volume of the preload required before spinal anesthesia. Reducing preload volume did not increase the incidence of maternal and neonatal adverse effects nor did it increase the total vasopressor dose. Moreover, reducing preload volume could relieve the heart burden of parturients, which has high clinical significance.

CLINICAL TRIAL REGISTRATION

The trial was registered with the Chinese Clinical Trial Registry at chictr.org.cn (registration number, ChiCTR2100055050) on December 31, 2021.

Evaluation of pre-induction dynamic arterial elastance as an adjustable predictor of post-induction hypotension: A prospective observational study

STUDY OBJECTIVE

Dynamic arterial elastance (Eadyn) has been suggested as a functional measure of arterial load. We aimed to evaluate whether pre-induction Eadyn can predict post-induction hypotension.

DESIGN

Prospective observational study.

PATIENTS

Adult patients undergoing general anesthesia with invasive and non-invasive arterial pressure monitoring systems.

MEASUREMENTS

We collected invasive and non-invasive Eadyns (n = 38 in each), respectively. In both invasive and non-invasive Eadyns, pre-induction Eadyns were obtained during one-minute tidal and deep breathing in each patient before anesthetic induction. Post-induction hypotension was defined as a decrease of >30% in mean blood pressure from the baseline value or any absolute mean blood pressure value of <65 mmHg for 10 min after anesthetic induction. The predictabilities of Eadyns for the development of post-induction hypotension were tested using receiver-operating characteristic curve analysis.

MAIN RESULTS

Invasive Eadyn during deep breathing showed significant predictability with an area under the curve (AUC) of 0.78 (95% Confidence interval [CI], 0.61-0.90, P = 0.001). But non-invasive Eadyn during tidal breathing (AUC = 0.66, 95% CI, 0.49-0.81, P = 0.096) and deep breathing (AUC = 0.53, 95% CI, 0.36-0.70, P = 0.75), and invasive Eadyn during tidal breathing (AUC = 0.66, 95% CI, 0.41-0.74, P = 0.095) failed to predict post-induction hypotension.

CONCLUSION

In our study, invasive pre-induction Eadyn during deep breathing -could predict post-induction hypotension. Despite its invasiveness, future studies will be needed to evaluate the usefulness of Eadyn as a predictor of post-induction hypotension because it is an adjustable parameter.

Carotid artery corrected flow time and respiratory variation of blood flow peak velocity for prediction of hypotension after induction of general anesthesia in adult patients undergoing emergency laparotomy for peritonitis: A prospective, observational study

Background and Aims

Doppler waveform analysis of carotid artery has been found to predict fluid responsiveness in patients undergoing elective surgeries. We evaluated the role of carotid artery corrected flow time (FTc) and respiratory variation of blood flow peak velocity (ðVpeak) in predicting post induction hypotension in patients undergoing emergency laparotomy for peritonitis.

Material and Methods

Adult patients (n = 60) with perforation peritonitis undergoing emergency laparotomy under general anesthesia (GA) were recruited in this prospective, observational study. Carotid ultrasonography was performed pre-induction, to determine FTc and ðVpeak. Post-induction hemodynamic parameters were recorded for 5 minutes. Spearman's rank correlation coefficient was used to determine the relationship between hypotension and carotid artery measurements.

Results

Post-induction hypotension occurred in 48.3% of patients. The carotid artery FTc was significantly lower (P = 0.008) in patients who developed post-induction hypotension, but ðVpeak was statistically similar (P = 0.62) in both groups. Spearman's rank correlation coefficient revealed a statistically significant correlation between FTc and systolic blood pressure (SBP) change at one-minute post induction (r2 = -0.29, P = 0.03); however statistical significance were not achieved at 2 minutes and 3 minutes (P = 0.05 at both time points). Carotid artery FTc had an area under the receiver operating characteristic (AUROC) curve (95% CI) of 0.70 (0.57-0.84) to predict post-induction hypotension and best cutoff value of 344.8 ms with a sensitivity and specificity of 61% and 79%, respectively. Carotid artery ðVpeak had an AUROC curve (95% CI) of 0.54 (0.39-0.69) to predict post-induction hypotension and best cutoff value of 7.9% with a sensitivity and specificity of 62% and 55%, respectively.

Conclusion

Carotid artery FTc and ðVpeak are not reasonable predictors of hypotension in patients undergoing emergency laparotomy for perforation peritonitis.

A preoperative ultrasound-based protocol for optimisation of fluid therapy to prevent early intraoperative hypotension: a randomised controlled study

BACKGROUND

Intraoperative hypotension is a risk factor for postoperative complications. Preoperative dehydration is a major contributor, although it is difficult to estimate its severity. Point-of-care ultrasound offers several potential methods, including measurements of the inferior vena cava. The addition of lung ultrasound may offer a safety limit. We aimed to evaluate whether the implication of an ultrasound-based preoperative fluid therapy protocol can decrease the incidence of early intraoperative hypotension.

METHODS

Randomised controlled study in a tertiary university department involves elective surgical patients of ASA 2-3 class, scheduled for elective major abdominal surgery under general anaesthesia with intubation. We randomised 40-40 patients; 38-38 were available for analysis. Conventional fluid therapy was ordered on routine preoperative visits. Ultrasound-based protocol evaluated the collapsibility index of inferior vena cava and lung ultrasound profiles. Scans were performed twice: 2 h and 30 min before surgery. A high collapsibility index (≥ 40%) indicated a standardised fluid bolus, while the anterior B-profile of the lung ultrasound contraindicated further fluid. The primary outcome was the incidence of postinduction and early intraoperative (0-10 min) hypotension (MAP < 65 mmHg and/or ≥ 30% of decrease from baseline). Secondary endpoints were postoperative lactate level, urine output and lung ultrasound score at 24 h.

RESULTS

The absolute criterion of postinduction hypotension was fulfilled in 12 patients in the conventional group (31.6%) and 3 in the ultrasound-based group (7.9%) (p = 0.0246). Based on composite criteria of absolute and/or relative hypotension, we observed 17 (44.7%) and 7 (18.4%) cases, respectively (p = 0.0136). The incidence of early intraoperative hypotension was also lower: HR for absolute hypotension was 2.10 (95% CI 1.00-4.42) in the conventional group (p = 0.0387). Secondary outcome measures were similar in the study groups.

CONCLUSION

We implemented a safe and effective point-of-care ultrasound-based preoperative fluid replacement protocol into perioperative care.

TRIAL REGISTRATION

The study was registered to ClinicalTrials.gov on 10/12/2021, registration number: NCT05171608 (registered prospectively on 10/12/2021).

Efficacy of inferior vena cava collapsibility index and caval aorta index in predicting the incidence of hypotension after spinal anaesthesia- A prospective, blinded, observational study

Background and Aim

Spinal anaesthesia-induced hypotension (SAIH) is a frequent side effect of spinal anaesthesia. SAIH is usually observed in patients with hypovolemia. Ultrasonography has evolved as a non-invasive tool for volume status assessment.

Methods

This prospective, blinded, observational study was conducted on 75 adult patients who required spinal anaesthesia after receiving ethical approval and registering the study. Ultrasonographic evaluation of the aorta and the inferior vena cava (IVC) was done preoperatively, and the IVC collapsibility index (IVCCI) and caval aorta index were calculated. The incidence of SAIH was recorded. The strength of the association between different parameters and SAIH was calculated. To find out the value of the optimal cut-off for the prediction of SAIH, receiver operating characteristic (ROC) analysis for various ultrasound parameters was done. The bidirectional stepwise selection was utilised for multivariate analysis to choose the single best predictor.

Results

SAIH was observed in 36 patients. Among demographic parameters, age, female gender, and height showed a medium correlation. Among ultrasonographic measurements, minimum IVC internal diameter (IVC_min) and IVCCI showed a strong association with SAIH. The best parameter regarding area under the ROC curve (AUC) and diagnostic accuracy was IVCCI (0.828 and 85%, respectively). On multivariate analysis, age (95% CI [1.01, 1.12], P = 0.024) and IVCCI (95% CI [1.05, 1.18], P < 0.001) were significant independent predictors. At a cut-off point of ≥43.5%, IVCCI accurately predicted SAIH (sensitivity 81% and specificity 90%).

Conclusion

Preoperative ultrasonographic assessment of IVC to evaluate its collapsibility index is a convenient, cost-effective, and reproducible tool for predicting SAIH.

Arterial Elastance: A Predictor of Hypotension Due to Anesthesia Induction

BACKGROUND

Hypotension is common after anesthesia induction and may have adverse outcomes. The aim of this study was to investigate whether arterial elastance (Ea) is a predictor of post-induction hypotension.

METHODS

Between January and June 2022, the hemodynamic parameters of 85 patients who underwent major surgery under general anesthesia were prospectively evaluated. The noncalibrated pulse contour device MostCare (Vytech, Vygon, Padua, Italy) was used to measure hemodynamic parameters before and after anesthesia induction. The duration of the measurements was determined from one minute before induction to 10 min after induction. Hypotension was defined as a greater than 30% decrease in mean arterial pressure from the pre-induction value and/or systolic arterial pressure of less than 90 mmHg. The patients were divided into post-induction hypotension (-) and (+) groups. For the likelihood of post-induction hypotension, a multivariate regression model was used by adding significantly different pre-induction parameters to the post-induction hypotension group.

RESULTS

The incidence of post-induction hypotension was 37.6%. The cut-off value of the pre-induction Ea for the prediction of post-induction hypotension was ≥1.08 mmHg m^-2mL^-1 (0.71 [0.59-0.82]). In the multivariate regression model, the likelihood of postinduction hypotension was 3.5-fold (1.4-9.1), increased by only an Ea ≥ 1.08 mmHg m^-2mL^-1.

CONCLUSION

Pre-induction Ea showed excellent predictability of hypotension during anesthetic induction and identified patients at risk of general anesthesia induction-related hypotension.

Effect of inferior vena cava respiratory variability-guided fluid therapy after laparoscopic hepatectomy: a randomized controlled clinical trial

BACKGROUND

After major liver resection, the volume status of patients is still undetermined. However, few concerns have been raised about postoperative fluid management. We aimed to compare gut function recovery and short-term prognosis of the patients after laparoscopic liver resection (LLR) with or without inferior vena cava (IVC) respiratory variability-directed fluid therapy in the anesthesia intensive care unit (AICU).

METHODS

This randomized controlled clinical trial enrolled 70 patients undergoing LLR. The IVC respiratory variability was used to optimize fluid management of the intervention group in AICU, while the standard practice of fluid management was used for the control group. The primary outcome was the time to flatus after surgery. The secondary outcomes included other indicators of gut function recovery after surgery, postoperative length of hospital stay (LOS), liver and kidney function, the severity of oxidative stress, and the incidence of severe complications associated with hepatectomy.

RESULTS

Compared with patients receiving standard fluid management, patients in the intervention group had a shorter time to anal exhaust after surgery (1.5 ± 0.6 days vs. 2.0 ± 0.8 days) and lower C-reactive protein activity (21.4 [95% confidence interval (CI): 11.9-36.7] mg/L vs. 44.8 [95%CI: 26.9-63.1] mg/L) 24 h after surgery. There were no significant differences in the time to defecation, serum concentrations of D-lactic acid, malondialdehyde, renal function, and frequency of severe postoperative complications as well as the LOS between the groups.

CONCLUSION

Postoperative IVC respiratory variability-directed fluid therapy in AICU was facilitated in bowel movement but elicited a negligible beneficial effect on the short-term prognosis of patients undergoing LLR.

TRIAL REGISTRATION

ChiCTR-INR-17013093.

Association between preoperative autonomic nervous system function and post-induction hypotension in elderly patients: a protocol for a cohort study

INTRODUCTION

Post-induction hypotension (PIH), which is prevalent among elderly patients, is associated with adverse perioperative outcomes. As a critical part of blood pressure regulation, baroreflex control is believed to be closely related to intraoperative blood pressure fluctuations. Spontaneous baroreflex sensitivity and heart rate variability measurement can aid evaluation of patients' autonomic function. This study aims to determine the association between preoperative decreased baroreflex function and PIH in elderly patients.

METHODS AND ANALYSIS

This prospective cohort study will enrol patients who are 65 years old and above, scheduled for elective non-cardiac surgery under general anaesthesia, and American Society of Anesthesiologists physical status I-III (n=180). Baseline assessment will include routine preoperative evaluations as well as symptoms and anamneses associated with baroreflex failure. Preoperative autonomic function monitoring will be performed through 20 min of continuous beat-to-beat heart rate and blood pressure monitoring using LiDCO rapid (Masimo Corporation, USA). The primary outcome will be PIH. Detailed use of anaesthetic agents during induction and maintenance will be documented for adjustment in multivariable analyses.

ETHICS AND DISSEMINATION

The Research Ethics Committee of Peking Union Medical College Hospital approved the study protocol (I-22PJ008). We aim to publish and disseminate our findings in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT05425147.

Pre-anesthesia ultrasound monitoring of subclavian vein diameter changes induced by modified passive leg raising can predict the occurrence of hypotension after general anesthesia: a prospective observational study

BACKGROUND

Perioperative hypotension increases postoperative complication rates and prolongs postoperative recovery time. Whether Passive Leg Raising test (PLR) and Subclavian Vein Diameter (DSCV) can effectively predict post-anesthesia hypotension remains to be tested. This study aimed to identify specific predictors of General Anesthesia (GA)induced hypotension by measuring DSCV in the supine versus PLR position.

METHODS

A total of 110 patients who underwent elective gynecological laparoscopic surgery under general anesthesia, were enrolled in this study. Before anesthesia, DSCV and theCollapsibility Index of DSCV(DSCV-CI) were measured by ultrasound, and the difference in maximal values of DSCV between supine and PLR positions was calculated, expressed as ΔDSCV. Hypotension was defined as Mean Blood Pressure (MBP) below 60mmhg or more than 30% below the baseline. Patients were divided into two groups according to the presence (Group H) or absence (Group N) of postanesthesia hypotension. The area under the receiver operating characteristic curve (ROC) and logistic regression analyses were used to evaluate the predictability of DSCV and other parameters for predicting preincision hypotension.

RESULTS

Three patients were excluded due to unclear ultrasound scans, resulting in a total of 107 patients studied. Twenty-seven (25.2%) patients experienced hypotension. Area under the ROC curve of ΔDSCV was 0.75 (P < 0.001) with 95% confidence interval (0.63-0.87), while DSCV and DSCV-CI were less than 0.7. The odds ratio (OR)of ΔDSCV was 1.18 (P < 0.001, 95%CI 1.09-1.27) for predicting the development of hypotension. ΔDSCV is predictive of hypotension following induction of general anesthesia.

CONCLUSIONS

ΔDSCV has predictive value for hypotension after general anesthesia.

TRIAL REGISTRATION

The trial was registered in the Chinese Clinical Trial Registry on 04/10/2021.

Carotid artery corrected flow time and respiratory variations of peak blood flow velocity for prediction of hypotension after induction of general anesthesia in elderly patients

Background

Postinduction hypotension is closely related to postoperative complications. Elderly patients with compromised cardiovascular compensatory reserve are more susceptible to hypotension after induction of general anesthesia. This study investigated whether the carotid artery corrected flow time (FTc) and respiratory variation of peak blood flow velocity in the common carotid artery (ΔVpeak) could predict postinduction hypotension in elderly patients.

Methods

This prospective observational study included elderly patients aged 65 to 75 who were scheduled for elective surgery under general anesthesia with ASA physical status class of I-II, without cardiovascular disease, hypertension, diabetes, or obesity. Anesthesia was induced by midazolam, sufentanil, and etomidate and was maintained by sevoflurane. The carotid artery FTc and ΔVpeak were measured by ultrasound before induction of anesthesia. Hemodynamic data were recorded before induction and then during the first 10 min after induction.

Results

Ninety-nine patients were included in the final analysis, of whom 63 developed postinduction hypotension. The area under the receiver operating characteristic curves was 0.87 (0.78 to 0.93) for carotid artery FTc and 0.67 (0.56 to 0.76) for ΔVpeak, respectively. The optimal cutoff value for predicting postinduction hypotension was 379.1 ms for carotid artery FTc, with sensitivity and specificity of 72.2 and 93.7%, respectively. The best cutoff value was 7.5% for ΔVpeak, with sensitivity and specificity of 55.6 and 75.0%, respectively.

Conclusions

The carotid artery FTc is a reliable predictor of postinduction hypotension in elderly patients with ASA status of I or II, without cardiovascular disease, hypertension, diabetes, or obesity. Elderly patients with a carotid artery FTc less than 379.1 ms before anesthesia have a higher risk of postinduction hypotension.

Trial registration

Clinical Trial Registry on August 2nd, 2020 (www.chictr.org.cn; ChiCTR2000035190).

Maximum inferior vena cava diameter predicts post-induction hypotension in hypertensive patients undergoing non-cardiac surgery under general anesthesia: A prospective cohort study

Background

Inferior vena cava (IVC) ultrasonography is a reliable variable that predicts post-induction hypotension (PIH) in patients undergoing surgery under general anesthesia. However, in patients with hypertension, the predictive performance of ultrasound IVC measurements needs further exploration.

Methods

This is a prospective cohort study. Adult patients with existing hypertension scheduled to undergo non-cardiac surgery under general anesthesia were eligible. An abdominal ultrasound examination was conducted immediately prior to anesthesia induction (0.03 mg kg^–1 midazolam, 0.3 mg kg^–1 etomidate, 0.4 μg kg^–1 sufentanil, and 0.6 mg kg^–1 rocuronium). IVC collapsibility index (IVC-CI) was calculated as (dIVC_max–dIVC_min)/dIVC_max, where dIVC_max and dIVC_min represent the maximum and minimum IVC diameters at the end of expiration and inspiration, respectively. PIH was defined as a reduction of mean arterial pressure (MAP) by >30% of the baseline or to <60 mmHg within 10 min after endotracheal intubation. The diagnostic performance of IVC-CI, dIVC_max, and dIVC_min in predicting PIH was also examined in a group of normotensive patients receiving non-cardiac surgery under the same anesthesia protocol.

Results

A total of 51 hypertensive patients (61 ± 13 years of age, 31 women) and 52 normotensive patients (42 ± 13 years of age, 35 women) were included in the final analysis. PIH occurred in 33 (64.7%) hypertensive patients and 19 (36.5%) normotensive patients. In normotensive patients, the area under the receiver operating curve (AUC) in predicting PIH was 0.896 (95% confidence interval [CI]: 0.804–0.987) for IVC-CI, 0.770 (95% CI: 0.633–0.908) for dIVC_max, and 0.868 (95% CI: 0.773–0.963) for dIVC_min. In hypertensive patients, the AUC in predicting PIH was 0.523 (95% CI: 0.354–0.691) for IVC-CI, 0.752 (95% CI: 0.621–0.883) for dIVC_max, and 0.715 (95% CI: 0.571–0.858) for dIVC_min. At the optimal cutoff (1.24 cm), dIVC_max had 54.5% (18/33) sensitivity and 94.4% (17/18) specificity.

Conclusion

In hypertensive patients, IVC-CI is unsuitable for predicting PIH, and dIVC_max is an alternative measure with promising performance.

Clinical trial registration

[http://www.chictr.org.cn/], identifier [ChiCTR2000034853].

Correlation of preoperative inferior vena cava diameter and inferior vena cava collapsibility index with preoperative fasting status, patient demography and general anaesthesia associated hypotension: A prospective, observational study

Background and Aims

A definitive cutoff of inferior venacava (IVC) diameter in expiration (dIVCmax) and inferior vena cava collapsibility index (IVCCI) for predicting general anaesthesia associated hypotension (GAAH) is not yet determined. Primary objective of this study was to determine the correlation of dIVCmax and IVCCI, with GAAH. Other objectives were to determine the correlation of these IVC parameters with preoperative fasting duration, temperature and humidity. The correlation of dIVCmax with patient demography was also studied.

Methods

A total of 110 adult patients undergoing elective surgery under general anaesthesia were included in the study. IVC ultrasonography was done in the preoperative room, 20 to 30 minutes before shifting the patient to the operating room. Hypotension at (hypo@) 2 minutes and 10 minutes after administering vecuronium was recorded.

Results

Hundred and seven patients were analysed. A significant positive correlation was present between patient height and dIVCmax (r = 0.25, P = 0.009). Area under receiver operating characteristics curve was 0.595 (95% confidence interval (CI) 0.485-0.705) and 0.568 (95% CI 0.458-0.679) for dIVCmax and IVCCI for predicting hypo@2 min, with a diagnostic accuracy of 54% and 53%, respectively. dIVCmax ≤1.14 cm had a sensitivity of 31% and specificity of 87% in predicting GAAH. IVCCI ≥63.3% could predict GAAH with 31% sensitivity and 84% specificity. No significant correlation was found between preoperative IVC parameters and preoperative fasting or environmental factors.

Conclusion

Both dIVCmax and IVCCI have poor diagnostic accuracy, with good specificity and low sensitivity in predicting GAAH. A steady formula for calculating baseline IVC diameter adjusted for patient demography is needed.

Pupil maximum constriction velocity predicts post-induction hypotension in patients with lower ASA status: a prospective observational study

Background

Individuals affected by autonomic dysfunction are at a higher risk of developing hypotension following anesthesia induction. Dynamic pupillometry has previously been employed as a means of assessing autonomic function. This prospective observational study was developed to determine whether pupillary light reflex (PLR) parameters can reliably predict post-induction hypotension (PIH).

Methods

This study enrolled patients with lower ASA status (I-II) undergoing elective surgery. PLR recordings for these patients prior to anesthesia induction were made with an infrared pupil camcorder, with a computer being used to assess Average Constriction Velocity (ACV), Maximum Constriction Velocity (MCV), and Constriction Ratio (CR). PIH was defined by a > 30% reduction in mean arterial pressure (MAP) or any MAP recording < 65 mmHg for at least 1 min from the time of induction until 10 minutes following intubation. Patients were stratified into PIH and non-PIH groups based on whether or not they developed hypotension.

Results

This study enrolled 61 total patients, of whom 31 (50.8%) exhibited one or more hypotensive episodes. Patients in the PIH group exhibited significantly smaller ACV (P = 0.003) and MCV values (P < 0.001), as well as a higher CR (P = 0.003). Following adjustment for certain factors (Model 2), MCV was identified as a protective factor for PIH (Odds Ratio: 0.369). Receiver operating characteristic (ROC) analyses revealed that relative to CR (AUC: 0.695, 95% CI: 0.563–0.806; P = 0.004), the reciprocal of MCV (1/MCV) offered greater value as a predictor of PIH (AUC: 0.803,95%CI: 0.681–0.894; P < 0.001).

Conclusion

These results indicate that pupil maximum constriction velocity is a reliable predictor of post-induction hypotension in individuals of ASA I-II status undergoing elective surgery.

Trial registration

This study was registered with the Chinese Clinical Trial Registry (registration number: ChiCTR2200057164, registration date: 01/03/2022).

Ultrasound dynamic monitoring of IVCD to guide application of CRRT in patients with renal failure combined with acute heart failure

We explored the application value of bedside ultrasound dynamic monitoring of the inferior vena cava diameter (IVCD) and collapse with sniff (inferior vena cava collapsibility index [IVCCI]) to guide dehydration adjustment in continuous renal replacement therapy (CRRT) in patients with combined renal failure and acute heart failure. We selected 90 patients with combined renal and acute heart failure who required CRRT in the intensive care unit (ICU) from January 2019 to June 2021. According to different blood volume assessment methods, patients were randomly divided into ultrasound, experience, and control groups. We compared serum creatinine, potassium, and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels; time to improved heart failure symptoms; CRRT time; ventilator use; ICU length of stay; vasopressor use; and incidence of adverse events among groups. There were no significant differences in serum creatinine, potassium, and NT-proBNP levels in pairwise comparisons among groups before and after CRRT (P > 0.05). The time to improved heart failure symptoms, CRRT time, and ICU length of stay in the ultrasound and experience groups were lower than those in the control group; the differences were statistically significant (P < 0.05). Ventilator use duration was lower in the ultrasound and experience groups compared with the control group, with a statistically significant difference between the ultrasound and control groups (P < 0.05). The duration of vasopressor use in the ultrasound and control groups was lower than that in the experience group; the difference was statistically significant (P < 0.05). The incidence of adverse events was lower in the ultrasound group compared with the experience and control groups; the difference was statistically significant (P < 0.05). Ultrasound dynamic monitoring of IVCD and collapse with sniff can accurately assess blood volume status, and provide guidance for dehydration adjustments in CRRT and rapid relief of heart failure symptoms in patients with combined renal and acute heart failure.

Reliability of Pre-Induction Inferior Vena Cava Assessment with Ultrasound for the Prediction of Post-Induction Hypotension in Neurosurgical Patients Undergoing Intracranial Surgery

Background

Hypotension is one of the most common complications following induction of general anesthesia. Preemptive diagnosis and correcting the hypovolemic status can reduce the incidence of post-induction hypotension. However, an association between preoperative volume status and severity of post-induction hypotension has not been established in neurosurgical patients. We hypothesized that preoperative ultrasonographic assessment of intravascular volume status can be used to predict post-induction hypotension in neurosurgical patients. Our study objective was to establish the relationship between pre-induction maximum inferior vena cava (IVC) diameter, collapsibility index (CI), and post-induction reduction in mean arterial blood pressure in neurosurgical patients.

Materials and Methods

A prospective observational study was conducted including 100 patients undergoing elective intracranial surgeries. IVC assessment was done before induction of general anesthesia. Receiver operating characteristic (ROC) curve analysis was used to determine the cutoff values of maximum and minimum IVC diameter (IVCD_max and IVCD_min, respectively) and CI for prediction of hypotension.

Results

Post-induction hypotension was observed in 41% patients. Patients with small IVCD_max and higher CI% developed hypotension. The areas under the ROC curve (AUCs) were 0.64 (0.53-0.75) for IVCD_max and 0.69 (0.59-0.80) for IVCD_min. The optimal cutoff values were1.38 cm for IVCD_max and 0.94 cm for IVCD_min. The AUC for CI was 0.65 (0.54-0.77) and the optimal cutoff value was 37.5%.

Conclusion

Pre-induction IVC assessment with ultrasound is a reliable method to predict post-induction hypotension resulting from hypovolemia in neurosurgical patients.

Prediction of post-induction hypotension by point-of-care echocardiography: A prospective observational study

BACKGROUND

Post-induction hypotension (PIH) is a common side effect of general anaesthesia and is associated with poor perioperative outcomes. We assessed the ability of two point-of-care echocardiographic variables to predict the occurrence of PIH: the passive leg raising-induced changes in the velocity-time integral of the left ventricular outflow tract (ΔVTI-PLR) and the inferior vena cava collapsibility index (IVC-CI).

METHODS

We studied 64 patients > 50 years scheduled for elective abdominal surgery. ΔVTI-PLR and IVC-CI were prospectively obtained before general anaesthesia induction. PIH was defined by a systolic arterial pressure < 90 mmHg or a mean arterial pressure < 65 mmHg or by a decrease in systolic or mean arterial pressure > 30% from pre-induction level. Intraclass correlation coefficients (ICCs) were calculated to assess the reproducibility of echocardiographic measurements. Receiver operating characteristic (ROC) curves with 95% confidence intervals (CIs) were generated to test the ability of ΔVTI-PLR and IVC-CI to predict the occurrence of PIH.

RESULTS

PIH occurred in 33 (51%) patients. The ICCs for VTI and IVC measurements showed excellent reproducibility. The occurrence of PIH was accurately predicted by ΔVTI-PLR with an area under the ROC curve (AUROC) of 0.89 (95% CI: 0.80-0.97), a threshold value of 18% with a sensitivity of 88% (95% CI: 71-97%) and a specificity of 84% (95% CI: 66-94%). The occurrence of PIH was poorly predicted by IVC-CI with an AUROC of 0.68 (95% CI: 0.54-0.80) and a threshold value of 42%.

CONCLUSIONS

ΔVTI-PLR, unlike IVC-CI, could reliably predict the occurrence of PIH. The use of ΔVTI-PLR could help individualise anaesthesia management to prevent PIH.

Ultrasound assessment of the inferior vena cava in children: A comparison of sub-xiphoid and right lateral coronal views

OBJECTIVES

The inferior vena cava collapsibility index (IVCCI) has been used to assess the respiratory variation of the inferior vena cava (IVC) diameter and hence intravascular volume. The sub-xiphoid view (SXV) is the standard view to evaluate the IVC. The right lateral transabdominal view (RLV) has been shown in adults to be an alternative view to evaluate the IVC when the SXV is not feasible. The aim of the study was to compare IVC dimensions from these two views and thus determine whether the RLV view can be used instead of the SXV in pediatric patients.

METHODS

We conducted a single-center prospective observational crossover study. Study subjects were ASA physical status 1-2 children, 1-12 years of age scheduled for elective surgery under general anesthesia. Anesthesia was maintained by mask with spontaneous ventilation with end-tidal sevoflurane at 2%-5% after the induction of anesthesia. IVCCI was measured using M-mode in both the SXV and RLV.

RESULTS

The study cohort included 50 children with a mean age of 5.1 years. The median value for the IVCCI-sx was 0.45 (IQR: 0.28-0.70) while the IVCCI-rl was 0.30 (0.19-0.5). The mean difference between the two groups was 0.12 (95% CI: 0.177-0.066, p < .001, two-tailed paired t-test). Spearman's rank correlation coefficient was 0.66. The univariate linear regression model was IVCCIsx = 0.21 + 0.77 × IVCCIrl.

CONCLUSIONS

IVCCIrl was lower than IVCCIsx. IVCCI measured from the right lateral view tended to overestimate the patient's fluid-responsiveness and therefore these two values are not interchangeable.

Preoperative assessment of inferior vena cava collapsibility index by ultrasound is not a reliable predictor of post-spinal anesthesia hypotension

BACKGROUND

Post-spinal anesthesia hypotension is of common occurrence, and it hampers tissue perfusion. Several preoperative factors determine patient susceptibility to hypotension. This study aimed to assess the effectiveness of the Inferior Vena Cava Collapsibility Index (IVCCI) for predicting intraoperative hypotension.

METHODS

One hundred twenty-nine adult patients who were scheduled for elective surgical procedures after administration of spinal (intrathecal) anesthesia were included in the study. Ultrasound evaluation of the Inferior Vena Cava (IVC) was done in the preoperative area, and the patients were shifted to the Operating Room (OR) for spinal anesthesia. An independent observer recorded the change in blood pressure after spinal anesthesia inside the OR.

RESULTS

Twenty-five patients developed hypotension (19.37%). Baseline systolic blood pressure and mean blood pressures were statistically higher in those patients who developed hypotension (p = 0.001). The logistic regression analysis for IVCCI and the incidence of hypotension showed r² of 0.025. Receiver Operating Characteristic (ROC) curve analysis demonstrated the Area Under the Curve (AUC) of 0.467 (95% Confidence Interval, 0.338 to 0.597; p = 0.615).

CONCLUSIONS

Preoperative evaluation of IVCCI is not a good predictor for the occurrence of hypotension after spinal anesthesia.

Inferior vena cava ultrasonography before general anesthesia cannot predict arterial hypotension in patients undergoing vascular surgery

INTRODUCTION

Intraoperative hypotension (IH) is an independent predictor of mortality. Some experts have suggested that ultrasound measurement of the inferior vena cava (IVC) in spontaneous ventilation can predict IH.

OBJECTIVE

To evaluate the capacity of ultrasound measures of IVC in spontaneous ventilation to predict episodes of IH after anaesthesia induction.

PATIENTS AND METHODS

We studied 55 high-risk cardiac patients undergoing vascular surgery. The maximum (dIVCmax) and minimum (dIVCmin) diameter of the IVC were measured and the collapsibility index CI = (dIVCmax-dIVCmin)/dIVCmax was calculated prior to anaesthesia induction. Three definitions of IH were used: systolic blood pressure (SBP) less than 100 mmHg, mean arterial pressure (MAP) less than 60 mmHg, and a decrease in MAP greater than or equal to 30% compared to baseline.

RESULTS

There were no significant differences in dIVCmax or in CI between patients presenting IH after anaesthesia induction and those who did not. ROC curves for dIVCmax showed an area under the curve of 0.55 (0.39-0.70), 0.69 (0.48-0.90), and 0.57 (0.42-0.73) and ROC curves for the CI were 0.62 (0.47-0.78), 0.60 (0.41-0.78) and 0.62 (0.47-0.78) for the 3 definitions of IH (<100 mmHg, MAP < 60 mmHg, and MAP ≥30% baseline), respectively.

CONCLUSIONS

Ultrasound measurements of IVC in spontaneous ventilation are not good predictors of IH after anaesthesia induction in these patients. The optimal cut-off points show low specificity and moderate sensitivity for predicting IH.