Intraoperative Hemodynamic Predictors of Mortality, Stroke, and Myocardial Infarction After Coronary Artery Bypass Surgery

The Impact of Intraoperative Vasopressor Use and Fluid Status on Flap Survival in Traumatic Lower Extremity Reconstruction

BACKGROUND

 Historically, the use of intraoperative vasopressors during free flap lower extremity (LE) reconstruction has been proposed to adversely affect flap survival due to concerns about compromising flap perfusion. This study aims to analyze the impact of intraoperative vasopressor use and fluid administration on postoperative outcomes in patients undergoing traumatic LE reconstruction.

METHODS

 Patients who underwent LE free flap reconstruction between 2015 and 2023 at a Level I Trauma Center were retrospectively reviewed. Statistical analysis was conducted to evaluate the association between vasopressor use and intraoperative fluids with partial/complete flap necrosis, as well as the differential effect of vasopressor use on flap outcomes based on varying fluid levels.

RESULTS

 A total of 105 LE flaps were performed over 8 years. Vasopressors were administered intraoperatively to 19 (18.0%) cases. Overall flap survival and limb salvage rates were 97.1 and 93.3%, respectively. Intraoperative vasopressor use decreased the overall risk of postoperative flap necrosis (OR 0.00005, 95% CI [9.11 × 10-9-0.285], p = 0.025), while a lower net fluid balance increased the risk of this outcome (OR 0.9985, 95% CI [0.9975-0.9996], p = 0.007). Further interaction analysis revealed that vasopressor use increased the risk of flap necrosis in settings with a higher net fluid balance (OR 1.0032, 95% CI [1.0008-1.0056], p-interaction =0.010).

CONCLUSION

 This study demonstrated that intraoperative vasopressor use and adequate fluid status may be beneficial in improving flap outcomes in LE reconstruction. Vasopressor use with adequate fluid management can optimize hemodynamic stability when necessary during traumatic LE microvascular reconstruction without concern for increased risk of flap ischemia.

The Effects of Angiotensin II versus Norepinephrine on Pulmonary Vascular Resistance in Cardiac Surgery: Post Hoc Analysis of a Randomized Controlled Trial

OBJECTIVES

To assess whether angiotensin II infusion increases pulmonary vascular resistance (PVR) relative to norepinephrine.

DESIGN

Secondary analysis of a double-blinded randomized feasibility study.

SETTING

Two tertiary metropolitan hospitals in Melbourne, Australia.

PARTICIPANTS

Fifty-eight adult patients undergoing cardiac surgery using cardiopulmonary bypass with an elevated risk of acute kidney injury (AKI).

INTERVENTIONS

Angiotensin II infusion compared with norepinephrine infusion.

MEASUREMENTS AND MAIN RESULTS

There was no significant difference in the primary outcome of PVR both intraoperatively and postoperatively between the angiotensin II group and the norepinephrine group. The study drug (angiotensin II or norepinephrine) infusion rate was associated with a small increase in PVR (β = 0.08; p = 0.01). The strongest association with PVR was the random effect (ie, patient effect) (p < 0.001). This effect was consistent across secondary outcomes. Randomization to norepinephrine instead of to angiotensin II was associated with reduced mean systemic arterial to mean pulmonary arterial pressure ratio postoperatively (β = -0.65; p = 0.01).

CONCLUSIONS

The results of this study suggest that in cardiac surgery patients and at doses used in the prior feasibility study, angiotensin II did not have significant effects on the pulmonary vasculature compared with norepinephrine. Moreover, at doses used in this study, neither drug appeared to have a substantial effect on the pulmonary circulation relative to surgical and patient factors.

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.

Oral midodrine for prophylaxis against post-spinal anesthesia hypotension during hip arthroplasty in elderly population: a randomized controlled trial

BACKGROUND

We aimed to evaluate the efficacy of midodrine as a prophylaxis against post-spinal hypotension in elderly patients undergoing hip arthroplasty.

METHODS

This randomized controlled trial included elderly patients undergoing hip arthroplasty under spinal anesthesia. Ninety minutes before the procedure, patients were randomized to receive either 5-mg midodrine or placebo (metoclopramide). After spinal anesthesia, mean arterial pressure (MAP) and heart rate were monitored every 2 min for 20 min then every 5 min until the end of the procedure. Post-spinal hypotension (MAP < 80% baseline) was treated with 10 mg ephedrine. The primary outcome was intraoperative ephedrine consumption. Secondary outcomes were the incidence of post-spinal hypotension, bradycardia, and hypertension (MAP increased by > 20% of the baseline reading).

RESULTS

We analyzed 29 patients in the midodrine group and 27 in the control group. The intraoperative ephedrine consumption was lower in the midodrine group than in the control group (median [quartiles]: 10 [0, 30] mg versus 30 [20, 43] mg, respectively, P-value: 0.002); and the incidence of intraoperative hypotension was lower in the midodrine group than that in the control group. The incidence of hypertension and bradycardia were comparable between the two groups.

CONCLUSION

The use of 5 mg oral midodrine decreased the vasopressor requirements and incidence of hypotension after spinal anesthesia for hip surgery in elderly patients.

CLINICAL TRIAL REGISTRATION

This study was registered on September 22, 2022 at clinicaltrials.gov registry, NCT05548985, URL: https://classic.

CLINICALTRIALS

gov/ct2/show/NCT05548985 .

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.

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.

Perioperative Decision-Making in Pulmonary Hypertension

Pulmonary hypertension (PH) is a haemodynamic manifestation of cardiorespiratory and non-cardiorespiratory pathologies. Cardiorespiratory pathologies account for nearly three-fourths of patients with PH. It is now increasingly being recognised due to routine requests for transthoracic echocardiographic examination in the perioperative setting in patients undergoing intermediate- to high-risk non-cardiac surgery. The increased risks of perioperative morbidity and mortality attributed to PH have been widely acknowledged in the literature. The importance of PH in perioperative decision-making and postoperative outcomes has had little mention in all the guidelines. Understanding the complexity of the pathophysiology of PH may help in anaesthetic and surgical decision-making. Preoperative evaluation and risk assessment are guided by the nature, extent, invasiveness, and duration of surgery. Surgical decision-making and anaesthetic management involve preoperative risk stratification, understanding the interactions between surgical procedures and PH, and understanding the interactions between anaesthetic procedures, PH, and cardiopulmonary interactions. Intraoperative and postoperative monitoring is crucial for maintaining the haemodynamic parameters and helps titrate anaesthetic agents and medication. This narrative review focusses on all issues related to anaesthetic and surgical challenges in patients with PH. This review aimed to suggest a preoperative evaluation plan, surgical decision-making, anaesthetic plan, and anaesthetic management based on the evidence available in the literature.

Inhaled milrinone in cardiac surgical patients: pharmacokinetic and pharmacodynamic exploration

Mean arterial pressure to mean pulmonary arterial pressure ratio (mAP/mPAP) has been identified as a strong predictor of perioperative complications in cardiac surgery. We therefore investigated the pharmacokinetic/pharmacodynamic (PK/PD) relationship of inhaled milrinone in these patients using this ratio (R) as a PD marker. Following approval by the ethics and research committee and informed consent, we performed the following experiment. Before initiation of cardiopulmonary bypass in 28 pulmonary hypertensive patients scheduled for cardiac surgery, milrinone (5 mg) was nebulized, plasma concentrations measured (up to 10 h) and compartmental PK analysis carried out. Baseline (R₀) and peak (R_max) ratios as well as magnitude of peak response (∆_Rmax-R0) were measured. During inhalation, individual area under effect-time (AUEC) and plasma concentration-time (AUC) curves were correlated. Potential relationships between PD markers and difficult separation from bypass (DSB) were explored. In this study, we observed that milrinone peak concentrations (41-189 ng ml^-1) and Δ_Rmax-R0 (- 0.12-1.5) were obtained at the end of inhalation (10-30 min). Mean PK parameters agreed with intravenous milrinone published data after correction for the estimated inhaled dose. Paired comparisons yielded a statistically significant increase between R₀ and R_max (mean difference, 0.58: 95% CI 0.43-0.73; P < 0.001). Individual AUEC correlated with AUC (r = 0.3890, r² = 0.1513; P = 0.045); significance increased after exclusion of non-responders (r = 4787, r² = 0.2292; P = 0.024). Individual AUEC correlated with ∆R_max-R0 (r = 5973, r² = 0.3568; P = 0.001). Both ∆R_max-R0 (P = 0.009) and CPB duration (P < 0.001) were identified as predictors of DSB. In conclusion, both magnitude of peak response of the mAP/mPAP ratio and CPB duration were associated with DSB.

The Conundrum of Systemic Arterial Pressure Management on Cardiopulmonary Bypass

The recently released EACTS/EACTA/EBCP guidelines on cardiopulmonary bypass (CPB) in adult cardiac surgery [...].

High versus low blood pressure targets for cardiac surgery while on cardiopulmonary bypass

BACKGROUND

Cardiac surgery is performed worldwide. Most types of cardiac surgery are performed using cardiopulmonary bypass (CPB). Cardiac surgery performed with CPB is associated with morbidities. CPB needs an extracorporeal circulation that replaces the heart and lungs, and performs circulation, ventilation, and oxygenation of the blood. The lower limit of mean blood pressure to maintain blood flow to vital organs increases in people with chronic hypertension. Because people undergoing cardiac surgery commonly have chronic hypertension, we hypothesised that maintaining a relatively high blood pressure improves desirable outcomes among the people undergoing cardiac surgery with CPB.

OBJECTIVES

To evaluate the benefits and harms of higher versus lower blood pressure targets during cardiac surgery with CPB.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search of databases was November 2021 and trials registries in January 2020.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing a higher blood pressure target (mean arterial pressure 65 mmHg or greater) with a lower blood pressure target (mean arterial pressure less than 65 mmHg) in adults undergoing cardiac surgery with CPB.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Primary outcomes were 1. acute kidney injury, 2. cognitive deterioration, and 3. all-cause mortality. Secondary outcomes were 4. quality of life, 5. acute ischaemic stroke, 6. haemorrhagic stroke, 7. length of hospital stay, 8. renal replacement therapy, 9. delirium, 10. perioperative transfusion of blood products, and 11. perioperative myocardial infarction. We used GRADE to assess certainty of evidence.

MAIN RESULTS

We included three RCTs with 737 people compared a higher blood pressure target with a lower blood pressure target during cardiac surgery with CPB. A high blood pressure target may result in little to no difference in acute kidney injury (risk ratio (RR) 1.30, 95% confidence interval (CI) 0.81 to 2.08; I² = 72%; 2 studies, 487 participants; low-certainty evidence), cognitive deterioration (RR 0.82, 95% CI 0.45 to 1.50; I² = 0%; 2 studies, 389 participants; low-certainty evidence), and all-cause mortality (RR 1.33, 95% CI 0.30 to 5.90; I² = 49%; 3 studies, 737 participants; low-certainty evidence). No study reported haemorrhagic stroke. Although a high blood pressure target may increase the length of hospital stay slightly, we found no differences between a higher and a lower blood pressure target for the other secondary outcomes. We also identified one ongoing RCT which is comparing a higher versus a lower blood pressure target among the people who undergo cardiac surgery with CPB.

AUTHORS' CONCLUSIONS

A high blood pressure target may result in little to no difference in patient outcomes including acute kidney injury and mortality. Given the wide CIs, further studies are needed to confirm the efficacy of a higher blood pressure target among those who undergo cardiac surgery with CPB.

Impact of hemodynamic instability during cytoreductive surgery on survival in high-grade serous ovarian carcinoma

Background

To evaluate the impact of intraoperative hypotension and hemodynamic instability on survival outcomes in patients with high-grade serous ovarian carcinoma (HGSOC).

Methods

We retrospectively identified patients with HGSOC, who underwent primary or interval debulking surgery between August 2013 and December 2019. We collected anesthesia-related variables, including the arterial blood pressure measurements (at 1-min intervals) during the surgery of patients. The cumulative duration of mean arterial blood pressure (MAP) readings under 65 mmHg and two performance measurements (median performance error [MDPE] and wobble) were calculated. We investigated associations between the factors indicating hemodynamic instability and prognosis.

Results

In total, 338 patients were included. Based on the cumulative duration of MAP under 65 mmHg, we divided patients into two groups: ≥30 min and <30 min. The progression-free survival (PFS) was worse in the ≥30 min group (n = 107) than the <30 min group (n = 231) (median, 18.2 vs. 23.7 months; P = 0.014). In multivariate analysis adjusting for confounders, a duration of ≥30 min of MAP under 65 mmHg was identified as an independent poor prognostic factor for PFS (adjusted HR, 1.376; 95% CI, 1.035–1.830; P = 0.028). Shorter PFS was observed in the group with a MDPE <−4.0% (adjusted HR, 1.351; 95% CI, 1.024–1.783; P = 0.033) and a wobble ≥7.5% (adjusted HR, 1.445; 95% CI, 1.100–1.899; P = 0.008). However, no differences were observed in overall survival.

Conclusion

This study suggests that the three intraoperative variables for hemodynamic instability, cumulative duration of MAP <65 mmHg, MDPE, and wobble, might be novel prognostic biomarkers for disease recurrence in patients with HGSOC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-10060-1.

No Association of Early Postoperative Heart Rate With Outcomes After Coronary Artery Bypass Grafting

BACKGROUND

Elevated perioperative heart rate potentially causes perioperative myocardial injury because of imbalance in oxygen supply and demand. However, large multicenter studies evaluating early postoperative heart rate and major adverse cardiac and cerebrovascular events (MACCEs) are lacking.

OBJECTIVE

To assess the associations of 4 postoperative heart rate assessment methods with in-hospital MACCEs after elective coronary artery bypass grafting (CABG).

METHODS

Using data from the eICU Collaborative Research Database in the United States from 2014 to 2015, the study evaluated postoperative heart rate measured during hospitalization within 24 hours after intensive care unit admission. Four heart rate assessment methods were evaluated: maximum heart rate, duration above heart rate 100/min, area above heart rate 100/min, and time-weighted average heart rate. The outcome was in-hospital MACCEs, defined as a composite of in-hospital death, myocardial infarction, angina, arrhythmia, heart failure, stroke, cardiac arrest, or repeat revascularization.

RESULTS

Among 2585 patients, the crude rate of in-hospital MACCEs was 6.2%. In multivariable logistic regression analysis, the adjusted odds ratios (95% CI) for in-hospital MAC-CEs assessed by maximum heart rate in each heart rate category (beats per minute: >100-110, >110-120, >120-130, and >130) were 1.43 (0.95-2.15), 0.98 (0.56-1.64), 1.47 (0.76-2.69), and 1.71 (0.80-3.35), respectively. Similarly, none of the other 3 methods were associated with MACCEs.

CONCLUSIONS

More research is needed to assess the usefulness of heart rate measurement in patients after CABG.

A Century of Technology in Anesthesia & Analgesia

Technological innovation has been closely intertwined with the growth of modern anesthesiology as a medical and scientific discipline. Anesthesia & Analgesia, the longest-running physician anesthesiology journal in the world, has documented key technological developments in the specialty over the past 100 years. What began as a focus on the fundamental tools needed for effective anesthetic delivery has evolved over the century into an increasing emphasis on automation, portability, and machine intelligence to improve the quality, safety, and efficiency of patient care.

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.

Intraoperative Invasive Blood Pressure Monitoring in Flap-Based Lower Extremity Reconstruction

BACKGROUND

Despite the lack of clear indications for the use of intra-arterial lines (IALs) for intraoperative hemodynamic monitoring, they are often used in a variety of settings. In this retrospective review of patients undergoing free tissue transfer (FTT) for lower extremity (LE) reconstruction, we sought to (1) identify patient factors associated with IAL placement, (2) compare hemodynamic measurements obtained via IAL versus noninvasive blood pressure (NIBP) monitoring, and (3) investigate whether method of hemodynamic monitoring affected intraoperative administration of blood pressure-altering medications.

METHODS

Patients undergoing LE FTT from January 2017 through June 2020 were retrospectively reviewed. Patients were pair matched based on flap donor site, sex, and body mass index to identify patient factors associated with IAL placement. Methods previously described by Bland and Altman (Lancet. 1986;327:307-310) were used to investigate agreement between IAL and NIBP measurements.

RESULTS

Sixty-eight patients were included with 34 patients in the IAL group and 34 in the NIBP group. Older patients (P = 0.03) and those with a higher Charlson Comorbidity Index (P = 0.05) were significantly more likely to have an IAL placed. Agreement analysis demonstrated that mean arterial pressures calculated from IAL readings were as much as 31 points lower or 28 points higher than those from NIBP. Bias calculations with this extent of difference suggest poor correlation between IAL readings and NIBP (R2 = 0.3027). There was no significant difference between groups in rate of administration of blood-pressure altering medications.

CONCLUSIONS

Surgeons should consider the risks and benefits of IAL placement on a case-by-case basis, particularly for patients who are young and healthy. Our findings highlight the need for clearer guidance regarding the use of IAL in patients undergoing LE FTT.

Predictive Value of Increased Perioperative Heart Rate for All-Cause Mortality After Cardiac Surgery: A Systematic Review and Meta-Analysis

Background: Accumulated studies have revealed that heart rates are associated with all-cause mortality in cardiac surgery patients, but the results remain controversial. This meta-analysis aimed to evaluate the predictive value of increased perioperative heart rate for all-cause mortality after cardiac surgery. Methods: We searched PubMed, Embase, Web of Science, and Cumulative Index of Nursing and Allied Health Literature (CINAHL) databases for studies from inception to October 11, 2021. Two researchers independently screened the studies. Titles, authors, publication years, and hazard ratios were extracted. We used a random-effects model to combine the HRs and 95% confidence intervals. Several subgroup analyses were conducted. Statistical significance was set at p < .05. Results: Eleven studies were included in the meta-analysis of 33,849 patients and 3166 (9.4%) deaths. The HR of higher perioperative heart rates was 2.09 (95% CI 1.53-2.86, p < .001, I² = 81%). The HR with a 10-bpm increase in preoperative heart rate was 1.19 (95% CI 1.11-1.26, p < .001, I² = 51%). Subgroup analysis showed patients with higher preoperative heart rates had an HR of 1.88 (95% CI 1.51-2.34, p < .001, I² = 0%), and patients with a higher postoperative heart rate had an HR of 2.29 (95% CI 1.28- 4.09, p < .0001, I² = 91%) compared to patients with lower postoperative heart rates. Conclusion: Increased perioperative heart rate is associated with all-cause mortality in patients undergoing cardiac surgery.

"Uncontrolled" Hypertension Is Not an Independent Risk Factor for Adverse Short-Term Outcomes Following Total Joint Arthroplasty

BACKGROUND

Uncontrolled hypertension (HTN) is a risk factor for mortality following elective surgery and poor hemodynamic control during total joint arthroplasty (TJA). However, the relationship between uncontrolled HTN and TJA outcomes remains poorly understood. The purpose of this study is to better define HTN parameters that are predictive of adverse arthroplasty outcomes.

METHODS

This is a retrospective cohort analysis on patients who underwent primary TJA for osteoarthritis between 2017 and 2021 at a large orthopedic practice. Uncontrolled HTN was defined as a systolic blood pressure (SBP) > 140 mm Hg, or diastolic blood pressure (DBP) > 90 mm Hg. Spearman's rank correlations were used to evaluate relationships among uncontrolled HTN and operative duration, hemoglobin drop, allogenic transfusions, length of stay, intraoperative/postoperative complications, and readmissions.

RESULTS

Four thousand three hundred forty-five patients met the selection criteria, of which 55.1% (N = 2394) presented with uncontrolled HTN. In total, 17.1% (N = 745) and 3.2% (N = 138) of patients had an SBP ≥ 160 and 180 mm Hg, respectively. In addition, 1.9% of patients (N = 84) presented with SBP ≥ 200 mm Hg (N = 13) and/or DBP ≥ 100 mm Hg (N = 71). Eight-four percent (N = 626) of patients who presented with SBP > 160 mm Hg had been preoperatively prescribed HTN control medications. Receiver operator curve analysis demonstrated poor predictive value of blood pressure for all aforementioned outcome variables.

CONCLUSION

Our findings suggest that as defined, uncontrolled HTN is not an appropriate individual predictor of TJA outcomes and should not be used as a "hard stop" when determining eligibility for elective surgery. Further research utilizing a larger cohort is needed to define the relationship between HTN and TJA outcomes.

Morbidity and mortality in patients managed with high compared with low blood pressure targets during on-pump cardiac surgery: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

Many believe that blood pressure management during cardiac surgery is associated with postoperative outcomes. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to determine the impact of high compared with low intraoperative blood pressure targets on postoperative morbidity and mortality in adults undergoing cardiac surgery on cardiopulmonary bypass (CPB). Our primary objective was to inform the design of a future large RCT.

SOURCE

We searched MEDLINE, EMBASE, Web of Science, CINAHL, and CENTRAL for RCTs comparing high with low intraoperative blood pressure targets in adult patients undergoing any cardiac surgical procedure on CPB. We screened reference lists, grey literature, and conference proceedings.

PRINCIPAL FINDINGS

We included eight RCTs (N =1,116 participants); all examined the effect of blood pressure management only during the CPB. Trial definitions of high compared with low blood pressure varied and, in some, there was a discrepancy between the target and achieved mean arterial pressure. We observed no difference in delirium, cognitive decline, stroke, acute kidney injury, or mortality between high and low blood pressure targets (very-low to low quality evidence). Higher blood pressure targets may have increased the risk of requiring a blood transfusion (three trials; n = 456 participants; relative risk, 1.4; 95% confidence interval, 1.1 to 1.9; P = 0.01; moderate quality evidence) but this finding was based on a small number of trials.

CONCLUSION

Individual trial definitions of high and low blood pressure targets varied, limiting inferences. The effect of high (compared with low) blood pressure targets on other morbidity and mortality after cardiac surgery remains unclear because of limitations with the body of existing evidence. Research to determine the optimal management of blood pressure during cardiac surgery is required.

STUDY REGISTRATION

PROSPERO (CRD42020177376); registered: 5 July 2020.

Perioperative renal protection

PURPOSE OF REVIEW

Acute kidney injury (AKI) is a common but underestimated syndrome in the perioperative setting. AKI can be induced by different causes and is associated with increased morbidity and mortality. Unfortunately, no specific treatment options are available at the moment.

RECENT FINDINGS

AKI is now understood as being a continuum ranging from normal kidney function over AKI and acute kidney disease to ultimately chronic kidney disease. The KDIGO organization recommend in 2012 implementation of preventive bundles in patients at high risk for AKI. In the perioperative setting, relevant measures include hemodynamic optimization, with careful consideration of blood pressure targets, adequate fluid therapy to maintain organ perfusion and avoidance of hyperglycaemia. These measures are most effective if patients at risk are identified as soon as possible and measures are implemented accordingly. Although current point of care functional biomarkers can detect patients at risk earlier than the established damage biomarkers, some components of the preventive bundle are still under investigation.

SUMMARY

Good evidence exists for the use of biomarkers to identify individual patients at risk for AKI and for the implementation of haemodynamic optimization, abdication of nephrotoxins, adequate fluid administration using balanced crystalloid solutions and glycaemic control. The data for using colloids or the degree of nephrotoxicity of contrast media still remain inconclusive.

Heterogeneous impact of hypotension on organ perfusion and outcomes: a narrative review

Arterial blood pressure is the driving force for organ perfusion. Although hypotension is common in acute care, there is a lack of accepted criteria for its definition. Most practitioners regard hypotension as undesirable even in situations that pose no immediate threat to life, but hypotension does not always lead to unfavourable outcomes based on experience and evidence. Thus efforts are needed to better understand the causes, consequences, and treatments of hypotension. This narrative review focuses on the heterogeneous underlying pathophysiological bases of hypotension and their impact on organ perfusion and patient outcomes. We propose the iso-pressure curve with hypotension and hypertension zones as a way to visualize changes in blood pressure. We also propose a haemodynamic pyramid and a pressure-output-resistance triangle to facilitate understanding of why hypotension can have different pathophysiological mechanisms and end-organ effects. We emphasise that hypotension does not always lead to organ hypoperfusion; to the contrary, hypotension may preserve or even increase organ perfusion depending on the relative changes in perfusion pressure and regional vascular resistance and the status of blood pressure autoregulation. Evidence from RCTs does not support the notion that a higher arterial blood pressure target always leads to improved outcomes. Management of blood pressure is not about maintaining a prespecified value, but rather involves ensuring organ perfusion without undue stress on the cardiovascular system.

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.

Adaptation to acute pulmonary hypertension in pigs

The extent of right ventricular compensation compared to the left ventricle is restricted and varies among individuals, which makes it difficult to define. While establishing a model of acute pulmonary hypertension in pigs we observed two different kinds of compensation in our animals. Looking deeper into the hemodynamic data we tried to delineate why some animals could compensate and others could not. Pulmonary hypertension (mean pressure 45 mmHg) was induced gradually by infusion of a stable thromboxane A₂ analogue U46619 in a porcine model (n = 22). Hemodynamic data (pressure‐volume loops, strain‐analysis of echocardiographic data and coronary flow measurements) were evaluated retrospectively for the short‐term right ventricular compensatory mechanisms and limits (Roehl et al. [2012] Acta Anaesthesiol. Scand., 56:449–58) 10 animals showed stable arterial blood pressures, whereas 12 pigs exhibited a significant drop of 16.4 ± 9.9 mmHg. Cardiac output and heart rate were comparable in both groups. In contrast, right ventricular contractility and coronary flow only rose in the stable group. The unchanging values in the decrease group correlated with an increasing ST‐segment depression and a loss of ventricular synchronism and resulted in a larger septum bulging to the right ventricle. Simultaneously, a reduced left‐ventricular end‐diastolic volume and a missing improvement in contractility in the posterior septal and inferior free wall of the left ventricle have been observed. Our findings suggest that right ventricular compensation during acute pulmonary hypertension is strongly dependent on the individual capability to increase coronary flow. The cause for inter‐individual variability could be the dimension and reactivity of the coronary system.

Incidence and variables associated with 30-day mortality after lung transplantation

BACKGROUND

With the introduction of the lung allocation score (LAS), sicker patients are prioritized for lung transplantation (LT). There is a lack of data regarding variables independently associated with 30-day mortality after LT.

METHODS

We queried the UNOS database for adult patients undergoing LT between 1989 and 2014. Patients with dual organ or previous transplantation and those with missing survival data were excluded. Mortality during the first 30 days after LT was the primary outcome variable.

RESULTS

The yearly trends indicate a statistically significant reduction in the 30-day mortality during the study period (P < 0.001, overall mortality: 5.5%) which has continued in the post-LAS era (P = 0. 014, overall mortality: 3.6%). Among patients with 30-day mortality, "primary non-function" (n = 118, 72.8%) was reported as the most common etiology. Transplant indication of vascular diseases, history of non-transplant cardiac or lung surgery, mean pulmonary pressures >35 mm Hg, disabled functional status, ECMO support, high LAS, ischemic time >6 hours, and blunt injury as the mechanism of donor death are independently associated with 30-day mortality.

CONCLUSION

The incidence of early mortality after LT continues to decline in the post-LAS era. Apart from the mechanism of donor death and ischemic time, early mortality appears to be primarily driven by the recipient characteristics.

Prolonged concurrent hypotension and low bispectral index ('double low') are associated with mortality, serious complications, and prolonged hospitalization after cardiac surgery

Background

Low bispectral index (BIS) and low mean arterial pressure (MAP) are associated with worse outcomes after surgery. We tested the hypothesis that a combination of these risk factors, a 'double low', is associated with death and major complications after cardiac surgery.

Methods

We used data from 8239 cardiac surgical patients from two US hospitals. The primary outcomes were 30-day mortality and a composite of in-hospital mortality and morbidity. We examined whether patients who had a case-averaged double low, defined as time-weighted average BIS and MAP (calculated over an entire case) below the sample mean but not in the reference group, had increased risk of the primary outcomes compared with patients whose BIS and/or MAP were at or higher than the sample mean. We also examined whether a prolonged cumulative duration of a concurrent double low (simultaneous low MAP and BIS) increased the risk of the primary outcomes.

Results

Case-averaged double low was not associated with increased risk of 30-day mortality {odds ratio [OR] 1.73 [95% confidence interval (CI) 0.94-3.18] vs reference; P =0.01} or the composite of in-hospital mortality and morbidity [OR 1.47 (95% CI 0.98-2.20); P =0.01] after correction for multiple outcomes. A prolonged concurrent double low was associated with 30-day mortality [OR 1.06 (95% CI 1.01-1.11) per 10-min increase; P =0.001] and the composite of in-hospital mortality and morbidity [OR 1.04 (95% CI 1.01-1.07), P =0.004].

Conclusions

A prolonged concurrent double low, but not a case-averaged double low, was associated with higher morbidity and mortality after cardiac surgery.

The effect of pulmonary hypertension on inpatient outcomes of laparoscopic procedures

The purpose of our analysis was to assess the effects of pulmonary hypertension (PH) on clinical outcomes of patients undergoing laparoscopic procedures. Pulmonary hypertension alters physiologic patterns that has the potential to complicate laparoscopic procedures, however, an in-depth analysis evaluating survival outcomes, complications, and associated comorbidities has not been done before. Data from the National Inpatient Survey were used to identify 179,663 patients without PH and 1453 patients with PH undergoing laparoscopic procedures from the years 2003-2013. In patients with pulmonary hypertension, the presence of the following comorbidities, congestive heart failure (OR 3.56) diabetes with chronic complications (OR 3.74) fluid and electrolyte disorders (OR 7.34) metastatic cancer (OR 14.42) and peripheral vascular disease (OR 3.12) increased in-patient mortality. In regards to post-operative complications, patients with PH were more likely to have cardiac complications defined as cardiac arrest, cardiac insufficiency, cardiorespiratory failure, or heart failure (OR 3.74). Patients with PH were also more likely to develop iatrogenic pneumothorax (OR 4.13) iatrogenic pulmonary embolism (OR 7.65) and post-operative urinary complications (OR 1.92). Overall, the comorbidity with the highest association with in-patient mortality was metastatic cancer and of all complications, patients with PH were most likely to develop iatrogenic pulmonary embolism. Preparing for these adversities, notably in patients with certain associated conditions has the potential to improve patient outcome.

Intraoperative factors associated with postoperative complications in body contouring surgery

BACKGROUND

Several preoperative factors have been shown to influence outcome of body contouring surgeries. The effect of intraoperative features, including fluid volume administered, hemodynamic and respiratory parameters, and body temperature on postoperative complication, has not been reported to date.

MATERIALS AND METHODS

All subsequent patients undergoing body contouring surgery in the Tel Aviv Medical Center between 2007 and 2012 were enrolled. Demographic and intraoperative data were collected and analyzed for possible associations with postoperative complications, including formation of seroma, hematoma/bleeding, other surgical site complications (infection, adhesiolysis, or need for debridement), formation of a hypertrophic scar, any documented, infection or a composite outcome of any of the previously mentioned.

RESULTS

Data of 218 patients were assessed. Mean (standard deviation) age of patients was 41(14) y. Intraoperative administration of higher volumes of fluids was significantly associated with formation of seroma (P = 0.01), hematoma/bleeding (P = 0.03), hypertrophic scar (P = 0.01), surgical site complications (P = 0.01), and a composite outcome (P < 0.001). Development of hematoma/bleeding was associated with longer periods of low (<35.6°C) intraoperative core temperature (72% versus 50% of surgery duration in patients who did not develop this complication, P < 0.05). Surgical site complications were associated with longer periods of intraoperative oxygen desaturation (saturation ≤92%, 4.2% versus 0.9% of surgery duration in patients who did not develop surgical site complications, P < 0.01).

CONCLUSIONS

Intraoperative moderate hypothermia, hypoxemia, and liberal fluid administration are associated with worse surgical outcome in patients undergoing body contouring surgery. Increased awareness of the potential adverse effects of these factors in body contouring surgery will enhance interventions aimed at avoiding and promptly treating such events.

Perioperative events in children with pulmonary hypertension undergoing non-cardiac procedures

Prior limited research indicates that children with pulmonary hypertension (PH) have higher rates of adverse perioperative outcomes when undergoing non-cardiac procedures and cardiac catheterizations. We examined a single-center retrospective cohort of children with active or pharmacologically controlled PH who underwent cardiac catheterization or non-cardiac surgery during 2006–2014. Preoperative characteristics and perioperative courses were examined to determine relationships between the severity or etiology of PH, type of procedure, and occurrence of major and minor events. We identified 77 patients who underwent 148 procedures at a median age of six months. The most common PH etiologies were bronchopulmonary dysplasia (46.7%), congenital heart disease (29.9%), and congenital diaphragmatic hernia (14.3%). Cardiac catheterizations (39.2%), and abdominal (29.1%) and central venous access (8.9%) were the most common procedures. Major events included failed planned extubation (5.6%), postoperative cardiac arrest (4.7%), induction or intraoperative cardiac arrest (2%), and postoperative death (1.4%). Major events were more frequent in patients with severe baseline PH (P = 0.006) and the incidence was associated with procedure type (P = 0.05). Preoperative inhaled nitric oxide and prostacyclin analog therapies were associated with decreased incidence of minor events (odds ratio [OR] = 0.32, P = 0.046 and OR = 0.24, P = 0.008, respectively), but no change in the incidence of major events. PH etiology was not associated with events (P = 0.24). Children with PH have increased risk of perioperative complications; cardiac arrest and death occur more frequently in patients with severe PH and those undergoing thoracic procedures. Risk may be modified by using preoperative pulmonary vasodilator therapy and lends itself to further prospective studies.

Population-based Assessment of Intraoperative Fluid Administration Practices Across Three Surgical Specialties

OBJECTIVE

To assess the variation in hospitals' approaches to intraoperative fluid management and their association with postoperative recovery.

BACKGROUND

Despite increasing interest in goal-directed, restricted-volume fluid administration for major surgery, there remains little consensus on optimal strategies, due to the lack of institution-level studies of resuscitation practices.

METHODS

Among 64 hospitals in a state-wide surgical collaborative, we profiled fluid administration practices during 8404 intestinal resections, 22,854 hysterectomies, and 1471 abdominopelvic endovascular procedures. We computed intraoperative fluid balance, accounting for patient morphometry, crystalloid, colloid, blood products, urine, blood loss, duration, and approach. We stratified hospitals by average fluid balance quartile, and compared patterns across disciplines and associations with risk-adjusted postoperative length of stay (pLOS).

RESULTS

There was wide variation in fluid balance between hospitals (P < 0.001, all procedures), but significant within-hospital correlation across operations (Pearson rho: intestinal-hysterectomy = 0.50, intestinal-endovascular = 0.36, hysterectomy-endovascular = 0.54, all P < 0.05). Highest fluid balance hospitals had significantly longer adjusted pLOS than lowest balance hospitals for intestinal resection (6.5 vs 5.7 d, P < 0.001) and hysterectomy (1.9 vs 1.7 d, P < 0.001), but not endovascular (2.1 vs 2.3 d, P = 0.69). Risk-adjusted complication rates were not associated with fluid balance rankings.

CONCLUSIONS

Hospitals' approaches to intraoperative fluid administration vary widely, and their practice patterns are pervasive across disparate procedures. High fluid balance hospitals have 12% to 14% longer risk-adjusted pLOS for visceral abdominal surgery, independent of patient complexity and complications. These findings are consistent with evidence that isovolemic resuscitation in enhanced recovery protocols accelerates recovery of bowel function.

A reduced gastric corpus microvascular blood flow during Ivor-Lewis esophagectomy detected by laser speckle contrast imaging technique

BACKGROUND

Reduced microvascular blood flow is related to anastomotic insufficiency following esophagectomy, emphasizing a need for intraoperative monitoring of the microcirculation. This study evaluated if laser speckle contrast imaging (LSCI) was able to detect intraoperative changes in gastric microcirculation.

METHODS

Gastric microcirculation was assessed prior to and after reconstruction of gastric continuity in 25 consecutive patients operated for adenocarcinoma with open Ivor-Lewis esophagectomy while hemodynamic variables were recorded.

RESULTS

During upper laparotomy, microcirculation at the corpus decreased by 25% from baseline to mobilization of the stomach (p = .008) and decreased further (to a total decrease of 40%) following gastric pull to the thorax (p = .013). On the other hand, microcirculation at the antrum did not change significantly after gastric mobilization (p = .091). The decrease in corpus microcirculation took place unrelated to central cardiovascular variables.

CONCLUSION

Using LSCI technique, we identified a reduced microcirculation at the corpus area during open Ivor-Lewis esophagectomy. LSCI provides an option for real-time assessment of gastric microcirculation and could form basis for intraoperative stabilization of the microcirculation.

The association between pre-operative variables, including blood pressure, and postoperative kidney function

We used multivariate analyses to assess the association of pre-operative variables with kidney function in 41,523 adults after scheduled surgery in a single large academic hospital. Eight variables were independently associated with a reduction in postoperative estimated glomerular filtration rate: pre-operative renal function; age; ASA physical status; cardiac failure; anaemia; cancer; type of surgery; and the lowest quartile of pre-operative mean arterial blood pressure (< 71 mmHg). The estimated glomerular filtration rate fell by a mean (95% CI) of 2.7 (0.04-5.40) ml.min^-1 .1.73 m^-2 for patients with a pre-operative mean arterial pressure < 71 mmHg, p = 0.047. The same variables and male sex were associated with postoperative acute kidney injury. The odds ratio (95% CI) for acute postoperative kidney injury was 1.9 (1.2-2.9) for patients with a pre-operative mean arterial blood pressure < 71 mmHg, p = 0.005.

Right Ventricular Longitudinal Strain Is Depressed in a Bovine Model of Pulmonary Hypertension

BACKGROUND

Pulmonary hypertension and resulting right ventricular (RV) dysfunction are associated with significant perioperative morbidity and mortality. Although echocardiography permits real-time, noninvasive assessment of RV function, objective and comparative measures are underdeveloped, and appropriate animal models to study their utility are lacking. Longitudinal strain analysis is a novel echocardiographic method to quantify RV performance. Herein, we hypothesized that peak RV longitudinal strain would worsen in a bovine model of pulmonary hypertension compared with control animals.

METHODS

Newborn Holstein calves were randomly chosen for induction of pulmonary hypertension versus control conditions. Pulmonary hypertension was induced by exposing animals to 14 days of hypoxia (equivalent to 4570 m above sea level or 430 mm Hg barometric pressure). Control animals were kept at ambient pressure/normoxia. At the end of the intervention, transthoracic echocardiography was performed in awake calves. Longitudinal wall strain was analyzed from modified apical 4-chamber views focused on the RV. Comparisons between measurements in hypoxic versus nonhypoxic conditions were performed using Student t test for independent samples and unequal variances.

RESULTS

After 14 days at normoxic versus hypoxic conditions, 15 calves were examined with echocardiography. Pulmonary hypertension was confirmed by right heart catheterization and associated with reduced RV systolic function. Mean systolic strain measurements were compared in normoxia-exposed animals (n = 8) and hypoxia-exposed animals (n = 7). Peak global systolic longitudinal RV strain after hypoxia worsened compared to normoxia (-10.5% vs -16.1%, P = 0.0031). Peak RV free wall strain also worsened after hypoxia compared to normoxia (-9.6% vs -17.3%, P = 0.0031). Findings from strain analysis were confirmed by measurement of tricuspid annular peak systolic excursion.

CONCLUSIONS

Peak longitudinal RV strain detected worsened RV function in animals with hypoxia-induced pulmonary hypertension compared with control animals. This relationship was demonstrated in the transthoracic echocardiographic 4-chamber view independently for the RV free wall and for the combination of the free and septal walls. This innovative model of bovine pulmonary hypertension may prove useful to compare different monitoring technologies for the assessment of early events of RV dysfunction. Further studies linking novel RV imaging applications with mechanistic and therapeutic approaches are needed.

Postintubation Hypotension in General Anesthesia: A Retrospective Analysis

BACKGROUND

Postintubation hypotension (PIH) is an adverse event associated with poor outcomes in emergency department endotracheal intubations. Study objective was to determine the incidence of PIH and its impact on outcomes following tracheal intubation in a general anesthesia population.

METHODS

Structured chart audit of adult patients intubated for a vascular surgery procedure at a tertiary care center over a 3-year period. Outcomes included in-hospital mortality, extended intensive care unit length of stay (ICU LOS), and requirement for postoperative (postop) hemodialysis or mechanical ventilation.

RESULTS

Incidence of PIH was 60% (837 of 1395). Patients who developed PIH had increased mortality (8.8% PIH vs 5.2% no-PIH; P = .014), extended ICU LOS (7.9% PIH vs 2.0% no-PIH; P < .001), and postop mechanical ventilation requirement (20.7% PIH vs 3.8% no-PIH; P < .001). When controlling for confounding factors, PIH was associated with extended ICU LOS (odds ratio [OR] 2.55, 95% confidence interval [CI] 1.01-6.62, P = .049), postop ventilation (OR 2.43, 95% CI 1.27-4.74, P = .008), and a composite end point (OR 1.72, 95% CI 1.02-2.92, P = .043).

CONCLUSIONS

Development of PIH occurs in 60% of patients undergoing intubation for vascular surgery and was associated with adverse outcomes including extended ICU LOS and postop ventilation requirement.

Significant Physiological Disturbances Associated With Non-Routine Event Containing and Routine Anesthesia Cases

OBJECTIVES

A nonroutine event (NRE) is defined as any event that deviates from ideal clinical care for a given patient in a specific clinical situation. We sought to compare anesthesia providers' reporting of NREs with the incidence of significant physiological disturbances (SPDs) detected via retrospective videotape review. SPD criteria were defined prestudy to be deviations of physiological parameters (heart rate, systolic blood pressure, and oxygen saturation) requiring clinical intervention. We hypothesized that SPDs would occur more frequently in NRE cases than in routine (no reported NRE) cases.

METHODS

A trained observer reviewed videotapes of anesthesia care from 16 randomly selected NRE-containing and 16 matched routine cases for SPD occurrence using custom software. Data were analyzed using nonparametric tests.

RESULTS

Although a preponderance of the anesthetic in both types of cases were uneventful (i.e., free of SPD in 97 ± 1.6% of routine case time versus 89 ± 3.9% of NRE case time), there was at least one SPD episode in 69% of routine and 88% of NRE cases. NRE-containing cases had significantly more SPDs than routine cases (1.4 ± 0.9 SPDs/case hour for NRE versus 0.8 ± 0.3 for routine cases). Twice as many SPDs during NRE-containing cases were clinically related to a reported NRE as opposed to unrelated.

CONCLUSIONS

SPDs occur more often in NRE-containing cases. The incidence of approximately one NRE-independent SPD per case was similar in NRE-containing and routine case. Further research is needed to ascertain the relationship of both NREs and SPDs to patient outcomes.

Hemodynamic effects of ephedrine and phenylephrine bolus injection in patients in the prone position under general anesthesia for lumbar spinal surgery

Ephedrine and phenylephrine (PE) are vasoconstrictors commonly used to restore the blood pressure (BP) to normal values. The aim of the present study was to investigate the effects of ephedrine and PE bolus administration on intra-arterial systolic BP (ISBP), intra-arterial diastolic BP (IDBP) and cardiac output (CO) in patients undergoing lumbar spine surgery in the prone position under general anesthesia (GA). In this prospective, randomized, and double-blind study, a total of 60 patients aged 20-60 years and undergoing elective lumbar spine surgery were administered either a single dose of ephedrine (0.1 mg/kg) or PE (1 µg/kg) through a central venous catheter as a bolus injection following the achievement of a stable hemodynamic status for ≥10 min. Following bolus injection of ephedrine or PE, a significant increase in ISBP was observed in the two experimental groups compared with pre-ephedrine and pre-PE values. The duration of the increment in ISBP however was significantly longer in the ephedrine group compared with the PE group. A similar response was observed in IDBP. A significant increase in CO began 1 min following ephedrine injection and lasted for the entire observation period, whereas the increase was only sustained for 3 min following bolus injection in the PE group. The results of the present study demonstrated that bolus ephedrine produces a more persistent pressor response and durable increase in CO and CI compared with PE when patients are in the prone position with GA for spine surgery.

Prone position results in enhanced pressor response to ephedrine compared with supine position during general anesthesia

STUDY OBJECTIVE

To elucidate and compare the pressor response to ephedrine in the prone or supine position during general anesthesia (GA).

DESIGN

Prospective cohort study.

SETTING

Department of General Surgery or Spine Surgery, Zhongda Hospital, Southeast University, Nanjing, China.

PATIENTS

Fifty-six patients who were scheduled to undergo elective surgery in the supine or prone position (n = 28 each) and using a generic GA protocol.

INTERVENTIONS

During surgery, the patients received intravenous (IV) ephedrine when their systolic blood pressure (SBP) decreased to 90 to 110 mm Hg.

MEASUREMENTS

Hemodynamic changes were measured at 1-minute intervals for 10 minutes and were compared with baseline.

MAIN RESULTS

Forty-nine patients (23 in the prone position and 26 in the supine position) completed the study. There were no significant differences between the groups with regard to demographic characteristics, hemodynamic parameters, end-tidal concentration of sevoflurane, and dose of propofol and remifentanil (all P> .05). After the bolus injection of ephedrine, a significant increase in SBP was observed in both groups compared to baseline, but the duration and magnitude of the increase in SBP were longer and greater in the prone position than in the supine position. The magnitude of increase of the mean blood pressure was significantly greater in the prone position compared to the supine position at 2 to 7 minutes after ephedrine injection. Ephedrine could cause significant increase in diastolic blood pressure 2 minutes after IV injection, which could last until at least 9 minutes in the prone position group compared to only for 5 minutes in the supine position group (all P< .05).

CONCLUSION

Compared to the supine position, the prone position could augment the pressor response to IV ephedrine during GA. Further studies are recommended to identify its association with other confounding factors such as surgery type or duration, patient history of cardiovascular disease, or patient hydration status.

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

Background

Hypotension is a common side effect of general anesthesia induction, and when severe, it is related to adverse outcomes. Ultrasonography of inferior vena cava (IVC) is a reliable indicator of intravascular volume status. This study investigated whether preoperative ultrasound IVC measurements could predict hypotension after induction of anesthesia.

Methods

One hundred four adult patients, conforming to American Society of Anesthesiologists physical status I to III, scheduled for elective surgery after general anesthesia were recruited. Maximum IVC diameter (dIVCmax) and collapsibility index (CI) were measured preoperatively. Before induction, mean blood pressure (MBP) was recorded. After induction, MBP was recorded for 10 min after intubation. Hypotension was defined as greater than 30% decrease in MBP from baseline or MBP less than 60 mmHg. Receiver operating characteristic curve analysis with gray zone approach and regression analyses were used.

Results

IVC scanning was unsuccessful in 13.5% of patients. Data from 90 patients were analyzed. After induction, 42 patients developed hypotension. Areas (95% confidence interval) under the curves were 0.90 (0.82 to 0.95) for CI and 0.76 (0.66 to 0.84) for dIVCmax. The optimal cutoff values were 43% for CI and 1.8 cm for dIVCmax. The gray zone for CI was 38 to 43% and included 12% of patients and that for dIVCmax was 1.5 to 2.1 cm and included 59% of patients. After adjusting for other factors, it was found that CI was an independent predictor of hypotension with the odds ratio of 1.17 (1.09 to 1.26). CI was also positively associated with a percentage decrease in MBP (regression coefficient = 0.27).

Conclusions

Preoperative ultrasound IVC CI measurement was a reliable predictor of hypotension after induction of general anesthesia, wherein CI greater than 43% was the threshold.

Hemodynamic Consequences of Malignant Ascites in Epithelial Ovarian Cancer Surgery*: A Prospective Substudy of a Randomized Controlled Trial

Malignant ascites (MA) is most commonly observed in patients scheduled for epithelial ovarian cancer (EOC) surgery and is supposed as a major risk factor promoting perioperative hemodynamic deterioration. We aimed to assess the hemodynamic consequences of MA on systemic circulation in patients undergoing cytoreductive EOC surgery.This study is a predefined post-hoc analysis of a randomized controlled pilot trial comparing intravenous solutions within a goal-directed algorithm to optimize hemodynamic therapy in patients undergoing cytoreductive EOC surgery. Ascites was used to stratify the EOC patients prior to randomization in the main study. We analyzed 2 groups according to the amount of ascites (NLAS: none or low ascites [<500 mL] vs HAS: high ascites group [>500 mL]). Differences in hemodynamic variables with respect to time were analyzed using nonparametric analysis for longitudinal data and multivariate generalized estimating equation adjusting the analysis for the randomized study groups of the main study.A total of 31 patients in the NLAS and 16 patients in the HAS group were analyzed. Although cardiac output was not different between groups suggesting a similar circulatory blood flow, the HAS group revealed higher heart rates and lower stroke volumes during surgery. There were no differences in pressure-based hemodynamic variables. In the HAS group, fluid demands, reflected by the time to reindication of a fluid challenge after preload optimization, increased steadily, whereas stroke volume could not be maintained at baseline resulting in hemodynamic instability after 1.5 h of surgery. In contrast, in the NLAS group fluid demands were stable and stroke volume could be maintained during surgery. Clinically relevant associations of the type of fluid replacement with hemodynamic consequences were particularly observed in the HAS group, in which transfusion of fresh frozen plasma (FFP) was associated to an improved circulatory flow and reduced vasopressor and fluid demands, whereas the administration of artificial infusion solutions was related to opposite effects.Malignant ascites >500 mL implies increased fluid demands and substantial alterations in circulatory blood flow during cancer surgery. Fresh frozen plasma transfusion promotes recovering hemodynamic stability in patients with malignant ascites >500 mL, in whom artificial infusion solutions could not prevent from hemodynamic deterioration.

Haemodynamic Responses to Tracheal Intubation Using Propofol, Etomidate and Etomidate-Propofol Combination in Anaesthesia Induction

Introduction: The aim of this study was to measure the haemodynamic responses to a etomidate-propofol combination used for anaesthesia induction and to compare the haemodynamic responses with the separate use of each drug.

Methods: The patients were randomly divided into three groups as group P (n = 30, propofol 2.5 mg kg^-1), group E (n = 30, etomidate 0.3 mg kg^-1) and group PE (n = 30, propofol 1.25 mg kg^-1 + etomidate 0.15 mg kg^-1). For each patient, the times of measurement of the heart rate (HR) and mean arterial pressure values were defined as baseline, after the induction, before the intubation, immediately after the intubation and 1, 2, 3, 4, 5 and 10 minutes after the intubation.

Results: In all 3 groups, a significant decrease in MAP values were seen at T2 and T3 compared to the baseline values, and this decrease was greater in group P compared to that in group E and PE (P < 0.001, P < 0.01). A significant increase was seen in all 3 groups in the mean arterial pressure (MAP) value at T4 after the intubation. When the groups were compared with each other, this increase was greater in group E than in the other two groups (with group P, P < 0.001; with group PE, P < 0.01).

Conclusion: Etomidate-propofol combination may be a valuable alternative when extremes of hypotensive and hypertensive responses due to propofol and etomidate are best to be avoided.