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

Pre-operative Ultrasonographic Evaluation of the Internal Jugular Vein Collapsibility Index and Inferior Vena Cava Collapsibility Index to Predict Post Spinal Hypotension in Pregnant Women Undergoing Caesarean Section

Background: Post spinal anesthesia hypotension (PSAH) is frequently encountered in anesthetic practice, especially during cesarean section. Ultrasound is a safe and easy technique for hemodynamic monitoring. Objectives: This study was conducted to assess the efficacy of pre-operative inferior vena cava collapsibility index (IVCCI) and internal jugular vein collapsibility index (IJVCI) in predicting PSAH. Methods: This cross-sectional blinded study included 55 pregnant females prepared for elective cesarean section. They were divided into two groups based on the incidence of PSAH: (1) cases with PSAH (26 cases); and (2) cases without PSAH (29 cases). All the cases underwent ultrasound-guided measurement of IVCCI and IJVCI. The efficacy of these parameters was assessed in predicting PSAH. Results: Cases in both groups expressed non-significant differences regarding demographic data. However, IVCCI had mean values of 38.27 and 23.97%, while IJVCCI had mean values of 46.50 and 33.41%, respectively, in cases with and without PSAH. For IVCCI, using a cut-off point of 33% had sensitivity and specificity (84.6 and 93.1%, respectively) for predicting PSAH, with a diagnostic accuracy of 89.1%. IJVCI had sensitivity and specificity of 84.6 and 82.8%, respectively, for predicting the same complication using a cut-off value of 38.5%. Conclusion: IVCCI and IJVCI are efficacious and reliable tools in predicting PSAH in pregnant ladies undergoing cesarean section, with a slight superiority for IVCCI regarding specificity and accuracy.

Inferior Vena Cava Collapsibility Index Can Predict Hypotension and Guide Fluid Management After Spinal Anesthesia

Purpose

We hypothesized that inferior vena cava collapsibility index (IVCCI)-guided fluid management would reduce the incidence of postspinal anesthesia hypotension in patients undergoing non-cardiovascular, non-obstetric surgery.

Methods

A receiver operating characteristic (ROC) curve was used to determine the diagnostic value of IVCCI for predicting hypotension after induction of spinal anesthesia and calculate the cut-off value. Based on the cut-off variation value, the following prospective randomized controlled trial aimed to compare the incidence of postspinal anesthesia hypotension between the IVCCI-guided fluid administration group and the standard fluid administration group. Secondary outcomes included the rate of vasoactive drug administration, the amount of fluid administered, and the incidence of nausea and vomiting.

Results

ROC curve analysis revealed that IVCCI had a sensitivity of 83.9%, a specificity of 76.3%, and a positive predictive value of 84% for predicting postspinal anesthesia hypotension at a cut-off point of >42%. The area under the curve (AUC) was 0.834 (95% confidence interval: 0.740–0.904). According to the cut-off variation value of 42%, the IVCCI-guided group exhibited a lower incidence of hypotension than the standard group [9 (15.3%) vs. 20 (31.7%), P = 0.032]. Total fluid administered was lower in the IVCCI-guided group than in the standard group [330 (0–560) mL vs. 345 (285–670) mL, P = 0.030].

Conclusions

Prespinal ultrasound scanning of the IVCCI provides a reliable predictor of hypotension following spinal anesthesia at a cut-off point of >42%. IVCCI-guided fluid management before spinal anesthesia can reduce the incidence of hypotension following spinal anesthesia.

Preoperative ultrasonographic evaluation of subclavian vein and inferior vena cava for predicting hypotension associated with induction of general anesthesia

Introduction:

Induction of general anesthesia is often associated with hypotension and is a common scenario faced by anesthesiologists. Intraoperative hypotension can have detrimental effects and cause various adverse effects leading to an extended hospital stay. Patients' preinduction volume status can have an effect on postinduction blood pressure. Ultrasonography is a useful tool for measuring intravascular volume status. We studied the ability of ultrasonographic measurement of subclavian vein (SCV) and inferior vena cava (IVC) diameter, collapsibility index (CI) to predict hypotension after induction of general anesthesia.

Materials and Methods:

We included 120 patients in our study. SCV measurements during spontaneous and deep inspiration and IVC measurements were taken before induction and postinduction blood pressure was monitored. Patients with mean arterial blood pressure <60 mmHg or with a 30% decrease from baseline were considered to be having hypotension.

Results:

The CI of IVC with a cutoff 37% showed sensitivity of 94% and specificity of 84% which was statistically significant. The CI of 36% of SCV during deep breathing was found to have high sensitivity and specificity of 90% and 87%.

Conclusion:

Our study in spontaneously breathing preoperative patients shows that SCV CI in deep breathing and IVC CI is very sensitive and reliable in predicting postinduction hypotension. Bedside ultrasound measurements can be easily done to obtain valuable information to recognize patients who could be at risk from postinduction hypotension.

Prediction of post-induction hypotension in young adults using ultrasound-derived inferior vena cava parameters: An observational study

Background and Aims

Inferior vena cava (IVC) diameter and its respiratory variability have been shown to predict post-induction hypotension with high specificity in a mixed population of patients. We assessed whether these parameters could be as reliable in healthy adult patients as in a mixed patient population.

Methods

In the present prospective observational study, 110 patients of either sex, aged between 18 and 50 years, belonging to American Society of Anesthesiologists class I and II, fasted as per the institutional protocol and scheduled for elective surgery under general anaesthesia were enroled. Prior to induction, ultrasound examination of IVC was done and variation in IVC diameter with respiration was assessed. Maximum and minimum IVC diameters [(dIVC_max) and (dIVC_min), respectively] over a single respiratory cycle were measured and collapsibility index (CI) was calculated. Vitals were recorded just before induction and at every minute after induction for 10 min. Episodes of hypotension (mean arterial pressure [MAP] <65 mmHg or fall in MAP >30% from baseline) during the observation period were recorded. The receiver operating characteristic (ROC) curve was constructed for determining optimum cut-off with sensitivity and specificity of IVC diameters and CI for development of hypotension.

Results

IVC was not visualised in 22 patients. Out of the remaining 88 patients, 17 (19.3%) patients developed hypotension after induction. The dIVC_max, dIVC_min and CI were comparable between patients who developed and who did not develop hypotension. The area under curve of ROC for CI, dIVC_max and dIVC_min was 0.51, 0.55 and 0.52, respectively, with optimum cut-off value of 0.46, 1.42 and 0.73, respectively.

Conclusion

Ultrasound-derived IVC parameters demonstrate poor diagnostic accuracy for prediction of hypotension after induction in healthy adult patients.

The key role of pulse wave transit time to predict blood pressure variation during anaesthesia induction

OBJECTIVE

To establish the relationship between pulse wave transit time (PWTT) before anaesthesia induction and blood pressure variability (BPV) during anaesthesia induction.

METHODS

This prospective observational cohort study enrolled consecutive patients that underwent elective surgery. Invasive arterial pressure, electrocardiography, pulse oximetry, heart rate and bispectral index were monitored. PWTT and BPV were measured with special software. Anaesthesia was induced with propofol, sufentanil and rocuronium.

RESULTS

A total of 54 patients were included in this study. There was no correlation between BPV and the dose of propofol, sufentanil and rocuronium during anaesthesia induction. Bivariate linear regression analysis demonstrated that PWTT (r = -0.54), age (r = 0.34) and systolic blood pressure (r = 0.31) significantly correlated with systolic blood pressure variability (SBPV). Only PWTT (r = -0.38) was significantly correlated with diastolic blood pressure variability (DBPV). Patients were stratified into high PWTT and low PWTT groups according to the mean PWTT value (96.8 ± 17.2 ms). Compared with the high PWTT group, the SBPV of the low PWTT group increased significantly by 3.4%. The DBPV of the low PWTT group increased significantly by 2.1% compared with the high PWTT group.

CONCLUSIONS

PWTT, assessed before anaesthesia induction, may be an effective predictor of haemodynamic fluctuations during anaesthesia induction.

Comparison of qualitative information obtained with the echocardiographic assessment using subcostal-only view and focused transthoracic echocardiography examinations: a prospective observational study

Purpose

To evaluate whether echocardiographic assessment using the subcostal-only window (EASy) compared with focused transthoracic echocardiography (FTTE) using three windows (parasternal, apical, and subcostal) can provide critical information to serve as an entry-point technique for novice sonographers.

Methods

We conducted a retrospective study to compare diagnostic information acquired during EASy and FTTE examinations on qualitative left ventricular (LV) size, LV contractility, right ventricular (RV) size, RV contractility, interventricular septal position, and the presence of a significant pericardial effusion. Anesthesiology residents (novice users) performed FTTE for hemodynamic instability and/or respiratory distress or to define volume status in the perioperative setting, and later collected images were grouped into EASy and FTTE examinations. Both examinations were reviewed independently by a board-certified cardiologist and an anesthesiologist proficient in critical care echocardiography. FTTE and EASy findings were compared utilizing Gwet’s AC1 coefficient to consider disagreement due to chance.

Results

We reviewed 102 patients who received FTTE over a period of 14 months. Of those, 82 had usable subcostal views and were included in the analysis. There was substantial agreement for qualitatively evaluating RV size (Gwet’s AC1, 0.70; 95% confidence interval [CI], 0.54 to 0.85), LV size (Gwet’s AC1, 0.73; 95% CI, 0.58 to 0.88), and LV contractility (Gwet’s AC1, 0.73; 95% CI, 0.58 to 0.88) utilizing EASy and FTTE. Additionally, there was an almost perfect agreement when assessing the presence of pericardial effusion (Gwet’s AC1, 0.98; 95% CI, 0.95 to 1.0) and RV contractility (Gwet’s AC1, 0.84; 95% CI, 0.74 to 0.95) and evaluating the motion of the interventricular septum (Gwet’s AC1, 0.92; 95% CI, 0.85 to 0.99).

Conclusions

When images could be obtained from the subcostal window (the EASy examination), qualitative diagnostic information was sufficiently accurate compared with information obtained during FTTE examination. Our findings suggest that the EASy examination can serve as the entry point technique to FTTE for novice clinicians.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12630-021-02152-6.

Can Inferior Vena Cava Diameter and Collapsibility Index Be a Predictor in Detecting Preoperative Intravascular Volume Change in Pediatric Patients?

Background: Inferior vena cava (IVC) ultrasound measurement is a reliable indicator used in the assessment of intravascular volume status. The aim of this study was to evaluate intravascular volume changes in pediatric patients by measuring the IVC diameter and collapsibility index (CI) in children whose oral feeding was restricted preoperatively. Material and Methods: From May 2018 to October 2018, a total of 55 pediatric patients who were scheduled for surgery were included in this prospective, observational, cohort study. Fasting and satiety IVC diameters and CIs of patients were determined by ultrasonographic evaluation twice: in the preoperative preliminary evaluation, when the patients were satiated, and before surgery, during a fasting period of 6–8 hours. Ultra-sonographic data were recorded and compared between fasting and satiety periods. Results: In the grey scale (B-mode), mean IVC diameter was significantly higher when the patients were satiated, compared to the measurements made just before surgery during the fasting period. In the M-mode, the mean IVC diameter was significantly higher only during the inspiratory phase when the patients were satiated, while during the expiratory phase it was detected to be statistically similar. Mean CI was significantly higher in the immediate preoperative period, compared to the assessment made when satiated. Conclusion: Preoperative ultrasound IVC diameter and CI measurement can be a practical and useful method for evaluating preoperative intravascular volume in children.

Ultrasound evaluation of inferior vena cava compression in tilted and supine term parturients

PURPOSE

Hypotension is common following spinal anesthesia (SA) during elective Cesarean delivery (CD). Although common practice is to alleviate inferior vena cava (IVC) compression, limited evidence supports a 15° tilt for CD. We measured collapsibility of the IVC in supine and 15° left lateral tilt positions with ultrasound before and after SA and phenylephrine infusion in term parturients.

METHODS

Twenty term parturients scheduled for CD were recruited for this prospective study. Ultrasound measurements of the IVC were taken 1) supine before SA, 2) tilted 15° before SA, 3) supine after SA, and 4) tilted 15° after SA. A phenylephrine infusion was begun after injection of SA. The primary outcome was to evaluate the impact of position on the IVC collapsibility index (IVCCI): a measure of the difference between the maximum and minimum IVC diameter with respiration.

RESULTS

The mean (standard deviation) IVCCI (%) before SA was higher in the supine 19.5 (8.0) than in the tilted 15.0 (6.4) position (mean difference, 4.5; 95% confidence interval [CI], 0.1 to 8.9; P = 0.04). After SA, there was no significant difference between IVCCI (%) in the supine 17.8 (8.3) and tilted 14.2 (6.9) position (mean difference, 3.5; 95% CI, -0.9 to 7.9; P = 0.13). There was no correlation between the pre-spinal IVVCI measurements and the quantity of phenylephrine used during the surgery.

CONCLUSION

The IVCCI was lower in the 15° tilt position than in the supine position, but not after SA with a phenylephrine infusion. Ultrasound imaging can help identify IVC compression.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT03410199); registered 18 January 2018.

Predictability of preoperative carotid artery-corrected flow time for hypotension after spinal anaesthesia in patients undergoing caesarean section: A prospective observational study

BACKGROUND

Spinal anaesthesia-induced hypotension is frequently reported in patients undergoing caesarean section. Mechanistically, sympathetic blockade reduces the systemic vascular resistance and the left ventricular preload, causing hypotension, which is augmented by aortocaval compression. The corrected blood flow time (FTc) is affected by the preload and is inversely related to the afterload.

OBJECTIVE

We hypothesised that the preanaesthetic carotid artery FTc could predict hypotension after induction in patients undergoing a caesarean section with spinal anaesthesia.

DESIGN

A prospective observational study.

SETTING

A tertiary referral centre in South Korea from September 2018 to November 2019.

PARTICIPANTS

Thirty-eight parturients scheduled for elective caesarean section under spinal anaesthesia.

INTERVENTIONS

Using carotid ultrasonography, FTc was measured twice prior to inducing spinal anaesthesia. FTc was calculated using both Bazett's (B) and Wodey's (W) formulae. Hypotension was defined as an SBP decrease to less than 80 mmHg, or less than 75% of baseline, or if symptoms consistent with hypotension occurred from the time of injection of the spinal anaesthetic until delivery.

MAIN OUTCOME MEASURES

The primary endpoint was to determine the predictive value of preanaesthetic FTc for postspinal hypotension during caesarean delivery.

RESULTS

Among the 35 patients who completed this study, hypotension occurred in 21 (60%). The areas under the receiver-operating characteristic curves for FTc (B) and FTc (W) were 0.905 [95% confidence interval (CI), 0.757 to 0.978, P < 0.001] and 0.922 (95% CI, 0.779 to 0.985, P < 0.001), respectively. The optimal cut-off values for predicting hypotension were 346.4 and 326.9 ms, respectively. The grey zone for FTc (B) and FTc (W) included 40 and 14% of the patients, respectively.

CONCLUSION

Preanaesthetic carotid artery FTc was a reliable indicator of postspinal hypotension in parturients. Considering the grey zone, Wodey's formula is better than Bazett's formula.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03631329.

A Flat Inferior Vena Cava on Computed Tomography Is Associated With Worse Outcomes in Emergency General Surgery

BACKGROUND

Several trauma studies have shown that a "flat" inferior vena cava (IVC) is associated with poor clinical outcomes, including hypovolemic shock, major bleeding, transfusions and mortality. These studies utilize IVC measurements on computed tomography (CT) scans, and rarely include emergency general surgery patients. We examine the association between IVC flatness and clinical outcomes in a series of patients with perforated viscus.

MATERIALS AND METHODS

Medical records at an academic hospital were reviewed of adults with perforated viscus. Patients who underwent laparotomy or laparoscopy were included if they underwent CT within 12 h prior to incision time. Perforated appendicitis was excluded. A ratio was calculated of the transverse to anterior-posterior diameter of the IVC at 3 locations, then averaged. Clinical outcomes were analyzed by the average IVC ratio.

RESULTS

A total of 83 patients were included. Using binomial regression, the average IVC ratio significantly correlated with ICU admission (OR 3.6, 95% CI 1.2 to 11) and acute kidney injury (OR 2.3, 95% CI 1.0 to 5.3), but not postoperative shock (OR 1.2, 95% CI 0.56 to 2.6).

CONCLUSIONS

A flat IVC on CT prior to an operation for perforated viscus was associated with worse outcomes, including increased rate of ICU admission and acute kidney injury. More outcomes research is needed to assess the potential role of IVC assessment in preoperative resuscitation.

Risk factors including preoperative echocardiographic parameters for post-induction hypotension in general anesthesia

BACKGROUND

Severe hypotension immediately after induction of general anesthesia (post-induction hypotension) is a common complication and is associated with a poor postoperative outcome. We hypothesized that post-induction hypotension results from cardiac dysfunction which can be assessed by preoperative echocardiography.

METHODS

We retrospectively enrolled 200 patients who had undergone elective surgery within 6 months after preoperative transthoracic echocardiography. The incidence of post-induction hypotension identified from anesthesia records was defined as a decrease in mean blood pressure to ≤50 mmHg after injection of induction anesthetics prior to surgery. Logistic regression analysis of patient characteristics and echocardiographic variables was used to identify the independent factors for post-induction hypotension.

RESULTS

Post-induction hypotension was found in 63 of the 200 cases (incidence 32%). Independent risk factors for post-induction hypotension were the presence of a regional wall motion abnormality (RWMA) [odds ratio (OR), 6.65.; 95% confidence interval (CI), 1.76 - 25.10], an elevated E/e' (OR, 1.13; 95% CI, 1.00 - 1.28), female gender (OR, 3.61; 95% CI, 1.37 - 9.56), and the use of an angiotensin II receptor blocker (OR, 3.17; 95% CI, 1.12 - 8.96).

CONCLUSIONS

Assessment of RWMA and E/e' with preoperative transthoracic echocardiography might be helpful for stratification of patients at a risk of post-induction hypotension in general anesthesia.

Prevention of Contrast-Induced Nephropathy by Inferior Vena Cava Ultrasonography-Guided Hydration in Chronic Heart Failure Patients

INTRODUCTION

Contrast-induced nephropathy (CIN) is a common complication resulting from the administration of contrast media. This study was designed to determine whether inferior vena cava (IVC) ultrasonography (IVCU)-guided hydration can reduce the risk of CIN in chronic heart failure patients undergoing coronary angiography or coronary angiography with percutaneous coronary intervention compared with standard hydration.

METHODS

This prospective clinical trial enrolled 207 chronic heart failure patients from February 2016 to November 2017, who were randomly assigned to either the IVCU-guided hydration group (n = 104) or the routine hydration group (n = 103). In the IVCU-guided group, the hydration infusion rate was set according to the IVC diameter determined by IVCU, while the control group received intravenous infusion of 0.9% saline at 0.5 mL/(kg·h). Serum Cr was measured before and 48-72 h after the procedure. All patients were followed up for 18 months. The incidence of nephropathy and major adverse cardiovascular or cerebrovascular events (MACCEs) was also compared between the 2 groups.

RESULTS

Statistically significant difference between the 2 groups regarding the occurrence of CIN was observed (12.5 vs. 29.1%, p = 0.004). The hydration volume of the IVCU-guided group was significantly higher than that of the routine group (p < 0.001). In addition, patients receiving IVCU-guided hydration had significantly lower risk of developing MACCEs than patients in the control group during the 18-month follow-up (14.4 vs. 27.2%, p = 0.027).

CONCLUSION

Our findings support that IVCU-guided hydration is superior to standard hydration in prevention of CIN and may substantially reduce longtime composite major adverse events.

Point-of-Care Ultrasound: Applications in Low- and Middle-Income Countries

Purpose of Review

This review highlights the applications of point-of-care ultrasound in low- and middle-income countries and shows the diversity of ultrasound in the diagnosis and management of patients.

Recent Findings

There is a paucity of data on point-of-care ultrasound in anesthesiology in low- and middle-income countries. However, research has shown that point-of-care ultrasound can effectively help manage infectious diseases, as well as abdominal and pulmonary pathologies.

Summary

Point-of-care ultrasound is a low-cost imaging modality that can be used for the diagnosis and management of diseases that affect low- and middle-income countries. There is limited data on the use of ultrasound in anesthesiology, which provides clinicians and researchers opportunity to study its use during the perioperative period.

Use of inferior venacaval collapsibility index in spinal anesthesia during orthopedic surgeries

Background:

Volume deficit is one of the predictors of hypotension. Inferior venacaval collapsibility index (IVCCI) can detect volume deficit and aids volume resuscitation in patients of intensive care unit.

Aims:

The primary aim was to compare the incidence of postspinal anesthesia hypotension (PSAH) in IVCCI measured and nonmeasured groups. The secondary aim was to determine IVCCI association with PSAH within IVCCI measured group in spite of fluid bolus.

Settings and Designs:

This was a prospective, randomized, controlled, single-blinded study.

Methodology:

One hundred patients posted for orthopedic surgery under spinal anesthesia (SA) were randomly divided as IVCCI measured (CI) and non-IVCCI measured (NCI) groups before SA. If IVCCI was more than 40% fluid bolus was given. Intraoperative hemodynamics was monitored. PSAH managed with fluids and vasopressors which were noted. Data collected were analyzed with unpaired t-test, Z-test, logistic regression test, and Pearson's correlation.

Results:

PSAH incidence was 18% in group (CI) whereas 38% in group (NCI), and the difference was statistically significant. Vasopressors given were higher in group NCI. Perioperative fluids were more in group CI, but the intraoperative fluids were more in group NCI. There was no statistically significant association between PSAH after fluid preloading and IVCCI within the IVCCI measured group.

Conclusion:

Prespinal anesthesia evaluation of IVCCI to optimize fluid therapy can reduce the incidence of PSAH in orthopedic surgeries and the vasopressor requirement, and hence, the association of IVCCI of more than 40% with PSAH.

Feasibility of Anesthesiologist-Performed Preoperative Echocardiography for the Prediction of Postinduction Hypotension: A Prospective Observational Study

Purpose

To determine if left ventricular or inferior vena cava (IVC) measurements are easier to obtain on point-of-care ultrasound by anesthesiologists in preoperative patients, and to assess the relationship between preoperative cardiac dimensions and hypotension with the induction of general anesthesia.

Methods

This prospective observational study was conducted at a large academic medical center. Sixty-three patients undergoing noncardiac surgeries under general anesthesia were enrolled. Ultrasound examinations were performed by anesthesiologists in the preoperative area. To ensure that hypotension represented both a relative and absolute decrease in blood pressure, both a mean arterial pressure (MAP) < 65 mmHg and a MAP decrease of >30% from preoperative value defined this outcome.

Results

Left ventricular measurements were more likely to be acquired than IVC measurements (97% vs. 79%). Subjects without adequate images to assess IVC collapsibility tended to have a higher body mass index (33.6 ± 5.5 vs. 28.5 ± 4.5, p=0.001). While high left ventricular end-diastolic diameter values were associated with a decreased odds of MAP < 65 mmHg (OR: 0.24, 95% CI: 0.07–0.83, p=0.023) or a MAP decrease of >30% from baseline alone (OR: 0.25, 95% CI: 0.07–0.83, p=0.023), the primary endpoint of both relative and absolute hypotension was not associated with preoperative left ventricular dimensions.

Conclusions

Preoperative cardiac ultrasound may be a more reliable way for anesthesiologists to assess patients' volume status compared to ultrasound of the IVC, particularly for patients with a higher body mass index.

Role of ultrasonographic inferior venacaval assessment in averting spinal anaesthesia-induced hypotension for hernia and hydrocele surgeries-A prospective randomised controlled study

Background and Aims:

Hypotension is one of the most common side effects of spinal anaesthesia and preoperative volume status is one of the predictive variables for developing spinal-induced hypotension (SIH). Inferior venacaval ultrasound (IVCUS) is effective to assess fluid responsiveness in critical care patients. The aim of this study was to evaluate the IVCUS-guided volume optimisation prior to spinal anaesthesia to prevent SIH and requirement of vasopressors.

Methods:

Eighty patients undergoing inguinal hernia/hydrocele surgeries under spinal anaesthesia were randomised into group A consisting of an IVCUS-guided volume optimisation before spinal anaesthesia and group B with no IVCUS assessment. Unpaired t-test and Z test were used for statistical analysis. Pearson's correlation coefficient was used to find correlation. The primary outcome was relative risk reduction in the incidence of SIH between the groups. Secondary outcomes were the need for vasopressor drugs, the total volume of fluids required throughout procedure, and correlation between IVC collapsibility index (IVCCI) versus prespinal fluids, IVCCI versus baseline mean arterial pressure (MAP).

Results:

The relative risk reduction in the incidence of SIH was lower in group A compared to group B which was 40% (P = 0.002 CI = 95%). The SIH in group A was 20% and group B was 50%. There was decreased requirement of vasopressors in group A compared to group B. Total IV fluids given was more in group A. There was a positive correlation between IVCCI and pre-spinal fluids.

Conclusion:

IVCUS assessment reduces the SIH as well as requirement of vasopressor for hernia and hydrocele surgeries.

Pre-operative transthoracic echocardiography in ambulatory surgery-A cross-sectional study

BACKGROUND

Cardiac disease and aberrations in central volume status are risk factors for perioperative complications, and should be identified prior to surgery. This study investigated the benefit of transthoracic echocardiography (TTE) for pre-operative identification of cardiac disease and hypovolemia in ambulatory surgery.

METHODS

Ninety-six patients, with a mean age of 63.5 ± 12.2 years and body mass index of 27.0 ± 4.3 kg/m² , scheduled for ambulatory surgery (breast, thyroid, and minor gastrointestinal), were consecutively enrolled in this prospective observational study. Pre-operative comprehensive TTE was performed in order to assess heart failure (HF), asymptomatic left ventricular dysfunction, valvular disease, and aberrations in central volume status.

RESULTS

Pre-operative TTE identified a total of 28 cases of HF, 13 cases of HF with reduced or moderately reduced, ejection fraction (EF), and 15 cases of HF with preserved EF. Furthermore, 46 cases of asymptomatic left ventricular (LV) dysfunction were identified. 44/96 patients were hypovolemic, 16 of whom in severe hypovolemia. Seven cases of previously unknown obstructive valvular or myocardial disease and six cases of right ventricular systolic dysfunction were identified. A total of 24% (23/96) were classified as potential critical hemodynamic findings. The number needed (NNT) to treat for pre-operative TTE in order to find one critical finding was 4.2.

CONCLUSION

In this ambulatory surgical cohort, a high prevalence of pre-operative LV dysfunction and aberrations in volume status was observed. The results demonstrate that pre-operative TTE contributed valuable hemodynamic information. The standard pre-operative assessment for this cohort might need to be revised.

Ultrasonographic inferior vena cava diameter response to trauma resuscitation after 1 hour predicts 24-hour fluid requirement

BACKGROUND

Identification of occult hypovolemia in trauma patients is difficult. We hypothesized that in acute trauma patients, the response of ultrasound-measured minimum inferior vena cava diameter (IVCDMIN), IVC Collapsibility Index (IVCCI), minimum internal jugular diameter (IJVDMIN) or IJV Collapsibility Index (IJVCI) after up to 1 hour of fluid resuscitation would predict 24-hour resuscitation intravenous fluid requirements (24FR).

METHODS

An NTI-funded, American Association for the Surgery of Trauma Multi-Institutional Trials Committee prospective, cohort trial was conducted at four Level I Trauma Centers. Major trauma patients were screened for an IVCD of 12 mm or less or IVCCI of 50% or less on initial focused assessment sonographic evaluations for trauma. A second IVCD was obtained 40 minutes to 60 minutes later, after standard-of-care fluid resuscitation. Patients whose second measured IVCD was less than 10 mm were deemed nonrepleted (NONREPLETED), those 10 mm or greater were repleted (REPLETED). Prehospital and initial resuscitation fluids and 24FR were recorded. Demographics, Injury Severity Score, arterial blood gasses, length of stay, interventions, and complications were recorded. Means were compared by ANOVA and categorical variables were compared via χ. Receiver operating characteristic curves analysis was used to compare the measures as 24FR predictors.

RESULTS

There were 4,798 patients screened, 196 were identified with admission IVCD of 12 mm or IVCCI of 50% or less, 144 were enrolled. There were 86 REPLETED and 58 NONREPLETED. Demographics, initial hemodynamics, or laboratory measures were not significantly different. NONREPLETED had smaller IVCD (6.0 ± 3.7 mm vs. 14.2 ± 4.3 mm, p < 0.001) and higher IVCCI (41.7% ± 30.0% vs. 13.2% ± 12.7%, p < 0.001) but no significant difference in IJVD or IJVCCI. REPLETED had greater 24FR than NONREPLETED (2503 ± 1751 mL vs. 1,243 ± 1,130 mL, p = 0.003). Receiver operating characteristic analysis indicates IVCDMIN predicted 24FR (area under the curve [AUC], 0.74; 95% confidence interval [CI], 0.64-0.84; p < 0.001) as did IVCCI (AUC, 0.75; 95% CI, 0.65-0.85; p < 0.001) but not IJVDMIN (AUC, 0.48; 95% CI, 0.24-0.60; p = 0.747) or IJVCI (AUC, 0.54; 95% CI, 0.42-0.67; p = 0.591).

CONCLUSION

Ultrasound assessed IVCDMIN and IVCCI response initial resuscitation predicts 24-hour fluid resuscitation requirements.

LEVEL OF EVIDENCE

Diagnostic tests or criteria, level II.

Pre-anaesthesia ultrasonography of the subclavian/infraclavicular axillary vein for predicting hypotension after inducing general anaesthesia: A prospective observational study

BACKGROUND

Bedside sonography of the inferior vena cava has been demonstrated to be a reliable tool for assessing intravascular volume status. Subclavian vein (SCV) assessment was proposed as a reasonable adjunct for measuring the inferior vena cava.

OBJECTIVE

We examined whether the preoperative diameter and collapsibility index of the SCV or the infraclavicular axillary vein could predict the incidence of hypotension after induction of general anaesthesia in patients undergoing laparoscopic cholecystectomy.

DESIGN

Prospective, observational study.

SETTING

Tertiary university hospital.

PATIENTS

Adults scheduled for laparoscopic cholecystectomy.

INTERVENTION

Sonographic evaluation of the SCV or the axillary vein (SCV-AV) before induction of anaesthesia.

MAIN OUTCOME MEASURES

The main outcome was the association between the SCV-AV measurements (diameter an collapsibility index) and intra-operative hypotension (IOH) after induction of anaesthesia.

RESULTS

Patients who developed IOH had a higher collapsibility index of the SCV-AV during spontaneous breathing (P = 0.009) and deep inspiration (P = 0.002). After adjusting for confounding variables, the collapsibility index of the SCV-AV during spontaneous breathing was not a significant predictor of a decrease in mean arterial blood pressure (MAP) after inducing anaesthesia (P = 0.127), whereas the collapsibility index of the SCV-AV during deep inspiration was a significant predictor (P < 0.001).

CONCLUSION

The collapsibility index of the SCV-AV during deep inspiration was a significant predictor of IOH occurrence and the percentage decrease in MAP after inducing anaesthesia. Further studies in patients with higher collapsibility index are needed to confirm our findings, before the collapsibility index of the SCV-AV can be recommended unequivocally for clinical use.

TRIAL REGISTRATION

This trial was registered on 8 September 2017 at the Clinical Trial Registry of Korea (https://cris.nih.go.kr/cris/index.jsp; Identifier: KCT0001078KCT0002457), and the first patient was enrolled on 14 October 2017.

Impact of deep breathing on predictability of stroke volume variation in spontaneous breathing patients

BACKGROUND

This study investigated the ability of stroke volume variation (SVV) during deep breathing to discriminate fluid responders among spontaneously breathing patients.

METHODS

Thirty patients undergoing general anaesthesia were enrolled and assessed before anaesthetic induction. Haemodynamic variables, including stroke volume (SV) and SVV, were measured using the ClearSight system during normal breathing. After these measurements, each patient was required to maintain deep breathing (6 breaths min^-1 ) and haemodynamic variables were recorded. Then, the table was adjusted to the Trendelenburg position (15°) for 2 minutes, and haemodynamic variables were measured. Receiver operating characteristic curves were created for SVV during normal and deep breathing, and the difference in SVV between normal and deep breathing (ΔSVV) to discriminate fluid responders (SV increase >10% after changing position). The correlation between SV increase and ΔSVV was examined using Pearson's correlation coefficient. The grey zone approach was used to assess the inconclusive range of the haemodynamic variables.

RESULTS

Receiver operating characteristic curve analysis indicated that ΔSVV showed good reliability in predicting fluid responsiveness (AUC: 0.850; 95% CI: 0.672-0.953; threshold: 4%, sensitivity: 75.0%, specificity: 88.9%], while SVV during normal breathing did not (AUC: 0.579; 95% CI: 0.386-0.756)]. Although SVV during deep breathing exhibited acceptable predictability (AUC: 0.778; 95% CI: 0.589-0.908), the sensitivity was not good (58.3%). With the grey zone approach, the inconclusive range of ΔSVV was small with the range of 1.4%-4.2% (23% of patients).

CONCLUSION

Deep breathing could improve the reliability of dynamic indices in spontaneously breathing patients.

TRIAL REGISTRATION

UMIN-CTR, identifer: UMIN000027970. https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000032040.

Carotid Artery Corrected Flow Time and Respiratory Variations of Peak Blood Flow Velocity for Prediction of Hypotension After Induction of General Anesthesia in Adult Patients Undergoing Elective Surgery: A Prospective Observational Study

OBJECTIVES

Hypotension is common after induction of general anesthesia, and intraoperative hypotension is associated with postoperative end-organ injury such as acute kidney injury and myocardial ischemia. This study was designed to determine the utility of the carotid corrected flow time (cFT) and carotid artery peak blood flow velocity variation (ðV_peak ) for prediction of hypotension after induction of general anesthesia.

METHODS

Adult patients (n = 112) undergoing any elective surgery under general anesthesia who fasted for at least 6 to 8 hours were recruited in this prospective observational study. The common carotid artery cFT and ðV_peak were measured with ultrasound 10 minutes before induction of general anesthesia. After that, general anesthesia with propofol was used, and hemodynamic data were collected until 3 minutes after induction of anesthesia.

RESULTS

The carotid cFT was significantly correlated with percentages of the fall in the systolic blood pressure at 2 minutes (P < .0001) and 3 minutes (P < .0001) and percentages of the fall in the mean arterial pressure at 1 minute (P = .0006), 2 minutes (P < .0001), and 3 minutes (P < .0001). The cFT was a predictor of hypotension after induction of general anesthesia, with an area under the receiver operating characteristic curve of 0.91. The best cutoff value obtained from this study was 330.2 milliseconds or less, which predicted postinduction hypotension with sensitivity and specificity of 85.7% and 96.8%, respectively. The ðV_peak was an inferior predictor of postinduction hypotension, with an area under the receiver operating characteristic curve of 0.68. The optimum cutoff value was 18.8%, with sensitivity and specificity of 61.9% and 67.4%.

CONCLUSIONS

The cFT measured in the common carotid artery is a reasonable predictor of hypotension after induction of general anesthesia in American Society of Anesthesiologists physical status I and II patients. Further studies are required to identify its role in high-risk patients such as older groups and patients with cardiovascular diseases and also to identify interobserver and intraobserver variability of cFT and ðV_peak measurements.

Ultrasound Measurement of Inferior Vena Cava Collapsibility as a Tool to Predict Propofol-Induced Hypotension

Background:

Hypotension is common under anesthesia and can cause organ underperfusion and ischemia, especially during induction. This could be because of the cardiovascular depressant and vasodilatory effects of anesthetic agents, as well as lack of surgical stimulation.

Aim of Study:

The aim was to evaluate the utility of preinduction inferior vena cava (IVC) measurement to predict significant hypotension after induction of anesthesia with propofol.

Settings and Design:

This was a prospective, open-label study conducted in a tertiary care institute.

Subjects and Methods:

This study was conducted on 50 patients undergoing general anesthesia. Ultrasound machine (Mindray® M7) was used to visualize IVC. The measurements taken were maximum diameter of IVC (IVC_max) and minimum diameter of IVC (IVC_min). IVC collapsibility index (IVC-CI) was calculated as (IVC_max − IVC_min)/IVC_max and was expressed as a ratio.

Statistical Tests Used:

Receiver operating characteristic (ROC) curve analysis and Chi-square test were used for statistical tests.

Results:

The relation between significant hypotension and IVC-CI was evaluated using ROC curve analysis. We found the area under curve to be 0.959 and a cutoff of 0.43 (43% collapsibility). The association of significant hypotension with IVC-CI of >43% was calculated and found to be statistically significant (P < 0.001). The sensitivity of IVC CI of >43% in predicting development of significant hypotension was 86.67% and the specificity was 94.29%. It had very high negative and positive predictive values (94.29% and 86.67%, respectively) with an accuracy of 92%.

Conclusion:

Patients with an IVC collapsibility of more than 43%, as assessed by ultrasonography, are more likely to develop significant hypotension after induction with propofol.

The role of right ventricular volumes and inferior vena cava diameters in the evaluation of volume status before colonoscopy

Background/aim

Ultrasonographic measurements of inferior vena cava (IVC) diameters and right ventricle (RV) volumes are important tools for the evaluation of intravascular volume. The current study investigates the association of IVC diameters and RV volumes before colonoscopy in prediction of postanesthesia hypotension.

Materials and methods

Seventy patients scheduled for colonoscopy were included in the study. Preoperatively, expirium (dIVC max) and inspirium (dIVC min) IVC diameters were measured using M-mode ultrasonography and the collapsibility index (IVC-CI) was calculated. Ventricular volumes and areas were also measured using transthoracic echocardiography. Postanesthesia hypotension was defined as mean arterial blood pressure of <60 mmHg or a decrease of >30% in the mean arterial pressure after sedation.

Results

Minimum and maximum IVC diameters were significantly lower (P = 0.005 and P < 0.001, respectively) and IVC-CI was significantly higher (P < 0.001) in patients who developed hypotension. Similarly, right ventricular end-diastolic area (RV-EDA), right ventricular end-systolic area (RV-ESA), right ventricular end-diastolic volume (RV-EDV), right ventricular end-systolic volume (RVESV), and left ventricular end-systolic volume (LV-ESV) values were significantly lower in patients with hypotension (P < 0.05). Logistic regression analysis showed that dIVC min and RV-ESA were independent predictors of hypotension.

Conclusion

IVC diameters and RV-ESA, RV-EDA, RV-ESV, and RV-EDV are good indicators of preoperative volume status and can be used to predict the patients at risk of developing hypotension.

Pre-operative ultrasonographic evaluation of inferior vena cava collapsibility index and caval aorta index as new predictors for hypotension after induction of spinal anaesthesia: A prospective observational study

BACKGROUND

Hypotension after spinal anaesthesia is a common side effect that may be harmful. Patients' susceptibility to intra-operative hypotension can be affected by many pre-operative factors.

OBJECTIVES

The current study aimed to evaluate the efficacy of both pre-operative inferior vena cava collapsibility index (IVCCI) and inferior vena cava to aorta diameter (IVC : Ao) index for predicting postspinal anaesthesia hypotension (PSAH).

DESIGN

Prospective observational blinded study.

SETTING

Operating room from June 2017 to February 2018.

PATIENTS

One hundred adult patients of both sexes, American Society of Anesthesiologists' physical status 1 or 2 scheduled for elective surgery under spinal anaesthesia were included in this study.

INTERVENTIONS

Patients received spinal anaesthesia performed at the level of L3 to 4 or L4 to 5 intervertebral space with the patient in the sitting position then placed in the supine position immediately after neuraxial block and kept supine throughout the study period (30 min). IVCCI and IVC : Ao index were assessed pre-operatively. Baseline noninvasive blood pressure was recorded before administration of spinal anaesthesia then every minute after spinal blockade for 30 min.

MAIN OUTCOME MEASURES

The primary outcome was to evaluate the predictive values of both IVCCI and IVC : Ao index for detecting PSAH and the secondary outcomes were to compare the predictive values of both IVCCI and IVC : Ao index and to detect other clinical predictors for PSAH using logistic regression analysis.

RESULTS

Forty-five patients developed PSAH (45%). IVCCI was significantly higher in patients who developed PSAH than in patients who did not, while IVC : Ao index was significantly lower in patients who developed PSAH than in patients who did not. Hypotension after induction of spinal anaesthesia was defined as an absolute value of SBP less than 90 mmHg, a decrease in SBP more than 30% of the baseline value or an absolute value of arterial blood pressure less than 60 mmHg. Logistic regression analysis revealed that IVCCI and IVC : Ao index were good predictors of the occurrence of PSAH. Receiver operating characteristic curve analysis showed that IVC : Ao index had a sensitivity of 96%, a specificity of 88%, and an accuracy of 95% to predict PSAH at a cut-off point less than 1.2. IVCCI had a sensitivity of 84%, a specificity of 77%, and an accuracy of 84% to predict PSAH at a cut-off point more than 44.7%.

CONCLUSION

Pre-operative IVCCI and IVC : Ao index are good predictors of the occurrence of PSAH. However, IVC : Ao index is a more powerful predictor than IVCCI.

Effect of remifentanil infusion on the hemodynamic response during induction of anesthesia in hypertensive and normotensive patients: a prospective observational study

Background

The induction of general anesthesia may cause hemodynamic instability. Remifentanil is often administered to suppress the hemodynamic response. We aimed to evaluate the effect of remifentanil infusion on the hemodynamic response to induction of anesthesia in hypertensive and normotensive patients.

Methods

Patients were divided into two groups: Group H (n = 102) were hypertensive patients and Group C (n = 107) were normotensive patients. During induction, all patients received 1 µg/kg of remifentanil as a loading dose over 2 minutes, followed by a continuous infusion at 0.05 µg/kg/minute. We analyzed the systolic, diastolic, and mean pressures and heart rate pre-induction, pre-intubation, immediately post-intubation, and at 2, 4, 6, 8, and 10 minutes after intubation.

Results

The systolic, diastolic, and mean pressures before induction were significantly higher in group H compared with group C, but there was no significant difference between the two groups immediately after intubation. Blood pressures immediately after intubation were similar to the pre-induction blood pressure. There was no significant difference in heart rate between the two groups at any time point.

Conclusions

Remifentanil infusion effectively attenuates the hemodynamic response to induction of general anesthesia in hypertensive and normotensive patients.

Predictors of 30-Day In-Hospital Mortality in Patients Undergoing Urgent Abdominal Surgery Due to Acute Peritonitis Complicated with Sepsis

Background

Sepsis is a life-threatening condition with high morbidity and mortality rate. Identifying early prediction factors of critical situations in intra-abdominal sepsis patients can help reduce mortality rates. This prospective study was carried out to evaluate the association of technically available factors with 30-day in-hospital mortality.

Material/Methods

There were 67 intra-abdominal sepsis patients included in the study; patients were observed for 30 days postoperatively. The data was processed using SPSS24.0 statistical analysis package. All tests that had a significance level of 0.05 were selected.

Results

Septic shock in association with increase in age per year showed increase the odds of mortality and prognosed 30-days in hospital mortality correctly in 79% of cases. The observed OR was 12.24 (P<0.001). Multiple logistic regression model 2 for the 30-day mortality identified a combination of septic shock, age (≥70 years), time from peritonitis symptoms to surgery prognose mortality with accuracy of 82%. The most accurate model to prognose 30-day in-hospital mortality included the presents of septic shock, age, time from peritonitis symptoms to surgery, drop of MAP <65 mmHg) post-induction, the odds of mortality 8.86 (P=0.001). Severe hypotension post-induction was more frequent in patients who were not diagnosed with sepsis (P=0.035).

Conclusions

The present study revealed a simple indicator for the risk for death under diffuse peritonitis patients complicated with sepsis. Septic shock, increase in age per year, peritonitis symptoms lasting more than 30 hours, and severe hypotension post-induction had a negative prognostic value for mortality in patients with intra-abdominal sepsis, and might be a high risk for 30-day mortality.

Role of inferior vena cava collapsibility index in the prediction of hypotension associated with general anesthesia: an observational study

BACKGROUND

Intraoperative hypotension increases 30-day mortality and the risks of myocardial injury and acute renal failure. Patients with inadequate volume reserve before the induction of anesthesia are highly exposed. The identification of latent hypovolemia is therefore crucial. Ultrasonographic measurement of the inferior vena cava collapsibility index (IVCCI) is able to detect volume responsiveness in circulatory shock. No current evidence is available regarding whether preoperative measurement of the IVCCI could identify patients at high risk for hypotension associated with general anesthesia.

METHODS

A total of 102 patients undergoing elective general surgery under general anesthesia with standardized propofol induction were recruited for this prospective observational study. The IVCCI was measured under spontaneous breathing. A collapsing (IVCCI≧50%) (CI+) and a noncollapsing (CI-) group were formed. Immediate postinduction changes in systolic and mean blood pressure were compared. The performance of the IVCCI as a diagnostic tool for predicting hypotension (systolic pressure < 90 mmHg or a ≥ 30% drop from the baseline) was evaluated by ROC curve analysis.

RESULTS

A total of 83 patients were available for analysis, with 20 in the CI+ and 63 in the CI- group, we excluded 19 previously eligible patients due to inadequate visualization of the IVC (7 cases), lack of adherence to the protocol (8 cases), missing data (2 cases) or change in anesthesiologic management (2 cases). The mean decrease in systolic pressure in the CI+ group was 53.8 ± 15.3 compared to 35.8 ± 18.1 mmHg in CI- patients (P = 0.0001). The relative mean arterial pressure change medians were 34.1% (IQR 23.2-43.0%) and 24.2% (IQR 17.2-30.2%), respectively (P = 0.0029). The ROC curve analysis for IVCCI showed an AUC of 64.8% (95% CI 52.1-77.5%). The selected 50% level of the IVCCI had a sensitivity of only 45.5% (95% CI 28.1-63.7%), but the specificity was high at 90.0% (78.2-96.7%). The positive predictive value was 75.0% (95% CI 50.9-91.3%), and the negative predictive value was 71.4% (95% CI 58.7-82.1%).

CONCLUSION

In spontaneously breathing preoperative noncardiac surgical patients, preoperatively detected IVCCI≧50% can predict postinduction hypotension with high specificity but low sensitivity. Despite moderate performance, IVCCI is an easy, noninvasive and attractive option to identify patients at risk and should be explored further.

Point of care ultrasound for the clinical anesthesiologist

Diagnostic ultrasonography was first utilized in the 1940s. The past 70+ years have seen an explosion in both ultrasound technology and availability of ultrasound technology to more and more clinicians. As ultrasound technology and availability have grown, the utility of ultrasound technology in the clinical setting as only been limited by clinicians' imagination. Due to its lack of radiation, non-invasive nature, and gentle learning curve, medical ultrasonography is now a tremendously useful Point of Care technology in the clinical arena. What follows is a discussion of Point of Care Ultrasound (PoCUS) and how it can be incorporated in the daily practice of any regional anesthesiology. While most regional anesthesiologists usually focus on the interventional aspects of ultrasonography (i.e. nerve blocks), our discussion will center on the diagnostic value of ultrasonography-especially concerning assessment of cardiac physiology and pathophysiology, gastric anatomy, airway anatomy, and intracranial pathophysiology. After reading and reviewing this chapter, the learner will have the knowledge to start training themselves in a variety of PoCUS exams that will allow rapid diagnosis of normal and abnormal patient conditions. Once an accurate diagnosis is established, the anesthesiologist and his/her team can then confidently optimize an anesthetic pain, prevent harm, and/or treat a patient condition. In this day and age, the ability to rapidly establish an accurate diagnosis cannot be overstated-especially in a critical situation. It is the authors' sincerest hope that the following discussion will help regional anesthesiologist to become even better and well-rounded clinical leaders.

Transesophageal Echocardiographic Measurements of the Superior Vena Cava for Predicting Fluid Responsiveness in Patients Undergoing Invasive Positive Pressure Ventilation

OBJECTIVES

Preoperative fasting, water deprivation, and intraoperative fluid loss and redistribution result in hypovolemia in patients undergoing surgery. Some findings have indicated that the superior vena cava (SVC) diameter and variation, as determined by transesophageal echocardiography during surgery, do not reflect central venous pressure effectively. This study aimed to compare and correlate the SVC diameter and variation with the stroke volume variation for predicting fluid responsiveness in patients undergoing invasive positive pressure ventilation.

METHODS

Thirty-six patients scheduled for elective gastrointestinal surgery under general anesthesia with invasive positive pressure ventilation were included in this study. After anesthesia induction, the stroke volume variation, SVC diameter, mean arterial pressure, central venous pressure, and pulse were recorded, and measurements after fluid challenge were recorded as well. The SVC variation was calculated before and after the fluid challenge.

RESULTS

After the fluid challenge, the SVC diameter markedly increased, whereas the SVC variation and stroke volume variation significantly decreased (P < .05). The optimal cutoff value for the SVC variation was 21.1%, and the area under the curve (AUC) from a receiver operating characteristic curve analysis was 0.849. The optimal cutoff value for the minimal SVC diameter was 1.135 cm, and that AUC was 0.929. In addition, the optimal cutoff value for the maximal SVC diameter was 1.480 cm, and the AUC was 0.862.

CONCLUSIONS

The minimal SVC diameter may be an effective indicator for predicting fluid responsiveness in patients undergoing invasive positive pressure ventilation.

Role of IVC collapsibility index to predict post spinal hypotension in pregnant women undergoing caesarean section. An observational trial

Background:

Postspinal anesthesia hypotension (PSH) in pregnant women is common and may lead to poor maternal and fetal outcome. Fluid loading in pregnant women before spinal anesthesia to prevent hypotension is of limited ability. We hypothesized that those women who are hypovolemic before spinal anesthesia may be at risk of PSH and inferior vena cava collapsibility index (IVCCI) will be able to identify hypovolemic parturients.

Methods:

In this prospective observational study, n = 45 women undergoing elective lower segment cesarean section with singleton pregnancy were recruited and IVCCI in left lateral tilt (with wedge) and supine position (without wedge) were noted by M-mode ultrasound (USG) before spinal anesthesia. After spinal anesthesia, changes in blood pressure were noted till 15 min after spinal anesthesia.

Results:

USG measurements were obtained in 40 patients and 23 of 40 patients (57.5%) had at least one episode of hypotension. Area under the ROC curve of IVCCI with wedge to predict PSH was 0.46 (95% CI 0.27, 0.64) and best cut-of value was 25.64 with a sensitivity and specificity of 60.9% and 35.5%, respectively. Area under the ROC curve of IVCCI without wedge to predict PSH was 0.38 (95% CI 0.19, 0.56) and best cut-of value was 20.4 with a sensitivity and specificity of 69.6% and 23.5%, respectively.

Conclusion:

We conclude that IVCCI is not a predictor of PSH in pregnant women undergoing elective cesarean section.

The utility of point-of-care ultrasound in the assessment of volume status in acute and critically ill patients

BACKGROUND

Volume resuscitation has only been demonstrated to be effective in approximately fifty percent of patients. The remaining patients do not respond to volume resuscitation and may even develop adverse outcomes (such as acute pulmonary edema necessitating endotracheal intubation). We believe that point-of-care ultrasound is an excellent modality by which to adequately predict which patients may benefit from volume resuscitation.

DATA RESOURCES

We performed a search using PubMed, Scopus, and MEDLINE. The following search terms were used: fluid responsiveness, ultrasound, non-invasive, hemodynamic, fluid challenge, and passive leg raise. Preference was given to clinical trials and review articles that were most relevant to the topic of assessing a patient's cardiovascular ability to respond to intravenous fluid administration using ultrasound.

RESULTS

Point-of-care ultrasound can be easily employed to measure the diameter and collapsibility of various large vessels including the inferior vena cava, common carotid artery, subclavian vein, internal jugular vein, and femoral vein. Such parameters are closely related to dynamic measures of fluid responsiveness and can be used by providers to help guide fluid resuscitation in critically ill patients.

CONCLUSION

Ultrasound in combination with passive leg raise is a non-invasive, cost- and time-effective modality that can be employed to assess volume status and response to fluid resuscitation. Traditionally sonographic studies have focused on the evaluation of large veins such as the inferior vena cava, and internal jugular vein. A number of recently published studies also demonstrate the usefulness of evaluating large arteries to predict volume status.

Can ultrasonographic measurement of carotid intima-media thickness predict hypotension after induction of general anesthesia?

Hypotension in patients under general anesthesia is prevalent and causes unfavorable outcomes. Carotid intima-media thickness (CIMT) is a surrogate marker for atherosclerosis and useful for evaluating the risk of cardiovascular diseases. We investigated the usefulness of preoperative CIMT measurement as a predictor of post-induction hypotension (PIH). The ultrasonographic measurement of CIMT was performed preoperatively on 82 patients scheduled for elective surgery under general anesthesia in a prospective, observational study. Mean blood pressure (MBP) was recorded before induction. Hypotension was defined as a 20% decrease in MBP from baseline. The ultrasonographic measurement of CIMT was unsuccessful in 2 (2.43%) patients, leaving 80 patients for analyses. Hypotension developed in 41 patients. CIMT was higher in the patient group with PIH than in the group without PIH (p < 0.001). There was statistically significant correlation between MBP decrease after induction and CIMT (r = 0.529, p < 0.0001). CIMT correlated positively with age (r = 0.739, p < 0.0001). The area under curve for CIMT was 0.753 [95% confidence interval (CI) 0.642-0.863]. The optimal cutoff value of CIMT was 0.65 mm with a sensitivity of 75.6% and a specificity of 74.4%. CIMT was an independent predictor of PIH after adjusting other factors with an odds ratio of 1.833 (95% CI 1.23-2.72; p = 0.003). The ultrasonographic imaging and measurement of CIMT can reliably predict hypotension with a 0.65-mm threshold level. We believe that the ultrasonographic measurements of CIMT may be included in point-of-care application in anesthesiology.

New antihypertensive medications and clinical implications

Hypertension remains a global public health issue and is a leading preventable risk factor for many causes of mortality and morbidity. Although it is generally managed as an outpatient chronic disease, anaesthetists will inevitably encounter patients with hypertension, ranging from undiagnosed asymptomatic to chronic forms with end-organ damage(s). An understanding of perioperative management of anti-hypertensive pharmacotherapy is crucial. Although many drugs are familiar, new drug groups that have relevance for blood pressure control and perioperative care have evolved in recent years. This article also describes new antihypertensive agents currently available or under development that could impact perioperative management.

Comparison of transverse short-axis classic and oblique long-axis “Syringe-Free” approaches for internal jugular venous catheterization under ultrasound guidance

Background and objectives

Methods

Results

Conclusion

Arterial Pressure Variation in Elective Noncardiac Surgery: Identifying Reference Distributions and Modifying Factors

BACKGROUND

Assessment of need for intravascular volume resuscitation remains challenging for anesthesiologists. Dynamic waveform indices, including systolic and pulse pressure variation, are demonstrated as reliable measures of fluid responsiveness for mechanically ventilated patients. Despite widespread use, real-world reference distributions for systolic and pulse pressure variation values have not been established for euvolemic intraoperative patients. The authors sought to establish systolic and pulse pressure variation reference distributions and assess the impact of modifying factors.

METHODS

The authors evaluated adult patients undergoing general anesthetics for elective noncardiac surgery. Median systolic and pulse pressure variations during a 50-min postinduction period were noted for each case. Modifying factors including body mass index, age, ventilator settings, positioning, and hemodynamic management were studied via univariate and multivariable analyses. For systolic pressure variation values, effects of data entry method (manually entered vs. automated recorded) were similarly studied.

RESULTS

Among 1,791 cases, per-case median systolic and pulse pressure variation values formed nonparametric distributions. For each distribution, median values, interquartile ranges, and reference intervals (2.5th to 97.5th percentile) were, respectively, noted: these included manually entered systolic pressure variation (6.0, 5.0 to 7.0, and 3.0 to 11.0 mmHg), automated systolic pressure variation (4.7, 3.9 to 6.0, and 2.2 to 10.4 mmHg), and automated pulse pressure variation (7.0, 5.0 to 9.0, and 2.0 to 16.0%). Nonsupine positioning and preoperative β blocker were independently associated with altered systolic and pulse pressure variations, whereas ventilator tidal volume more than 8 ml/kg ideal body weight and peak inspiratory pressure more than 16 cm H2O demonstrated independent associations for systolic pressure variation only.

CONCLUSIONS

This study establishes real-world systolic and pulse pressure variation reference distributions absent in the current literature. Through a consideration of reference distributions and modifying factors, the authors' study provides further evidence for assessing intraoperative volume status and fluid management therapies.