Mechanisms contributing to hypotension after anesthetic induction with sufentanil, propofol, and rocuronium: a prospective observational study

Mitigating Intraoperative Hypotension: A Review and Update on Recent Advances

Intraoperative hypotension (IOH) is a common occurrence during anesthesia administration for various surgical procedures and is linked to postoperative adverse outcomes. Factors contributing to IOH include hypovolemia, vasodilation, and impaired contractility, often combined with patient comorbidities. Strategies for mitigating IOH have been developed and are continually being updated with new research and technological advancements. These strategies include personalized blood pressure thresholds, pharmacologic measures, and the use of predictive tools. However, the management of IOH also requires careful consideration of patient-specific comorbidities and the use of appropriate treatment options.

Defining Postinduction Hemodynamic Instability With an Automated Classification Model

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Comparative Electroencephalographic Profile of a New Anesthetic and Anticonvulsant That Is Selective for the GABAAR Slow Receptor Subtype

BACKGROUND

Anesthetics like propofol increase electroencephalography (EEG) power in delta frequencies (0.1-4 Hz), with a decrease of power in bandwidths >30 Hz. Propofol is nonselective for gamma amino butyric acid type A receptor subtypes (GABAAR) as it enhances all 3 GABAAR subtypes (slow, fast, and tonic). Our newly developed anesthetic class selectively targets GABAAR-slow synapses to depress brain responsiveness. We hypothesized that a selective GABAAR-slow agonist, KSEB 01-S2, would produce a different EEG signature compared to the broad-spectrum GABAAR agonist (propofol), and tested this using rat EEG recordings.

METHODS

Male rats were studied after Institutional Animal Care and Use Committees (IACUC) approval from the US Army Medical Research Institute of Chemical Defense and the University of Michigan. Rats were anesthetized using isoflurane (3%-5% induction, 1%-3% maintenance) with oxygen at 0.5 to 1.0 L/min. Stainless steel screws were placed in the skull and used to record subcranial cortical EEG signals. After recovery, either propofol or KSEB 01-S2 was administered and effects on EEG signals were analyzed.

RESULTS

As previously reported, propofol produced increased power in delta frequencies (0.1-4 Hz) compared to predrug recordings and produced a decrease in EEG power >30 Hz but no significant changes were seen within ±20 seconds of losing the righting reflex. By contrast, KSEB 01-S2 produced a significant increase in theta frequency percent power (median 14.7%, 16.2/13.8, 75/25 confidence interval; to 34.7%, 35/31.8; P < .015) and a significant decrease in low gamma frequency percent power (16.9%, 18.6/15.8; to 5.45%, 5.5/5.39; P < .015) for all rats at ± 20 seconds of loss of consciousness (LOC). Both anesthetics produced a flattening of chaotic attractor plots from nonlinear dynamic analyses, like that produced by volatile and dissociative anesthetics at LOC.

CONCLUSIONS

KSEB 01-S2 produced a markedly different EEG pattern, with a selective increase observed in the theta frequency range. KSEB 01-S2 also differs markedly in its activity at the GABAAR-slow receptor subtype, suggesting a possible mechanistic link between receptor subtype specificity and EEG frequency band signatures. Increased theta together with depressed gamma frequencies is interesting because GABAAR slow synapses have previously been suggested to underlie theta frequency oscillations, while fast synapses control gamma activity. These reciprocal effects support a previous model for theta and nested gamma oscillations based on inhibitory connections between GABAAR fast and slow interneurons. Although each anesthetic produced a unique EEG response, propofol and KSEB 01-S2 both increased slow wave activity and flattened chaotic attractor plots at the point of LOC.

Vasoconstriction with phenylephrine increases cardiac output in preload dependent patients

General Anaesthesia (GA) is accompanied by a marked decrease in sympathetic outflow and thus loss of vasomotor control of cardiac preload. The use of vasoconstriction during GA has mainly focused on maintaining blood pressure. Phenylephrine (PE) is a pure α1-agonist without inotropic effects widely used to correct intraoperative hypotension. The potential of PE for augmenting cardiac stroke volume (SV) and -output (CO) by venous recruitment is controversial and no human studies have explored the effects of PE in preload dependent circulation using indicator dilution technique. We hypothesized that PE-infusion in patients with cardiac stroke volume limited by reduced preload would restore preload and thus augment SV and CO. 20 patients undergoing GA for gastrointestinal surgery were monitored with arterial catheter and LiDCO unity monitor. Upon stable haemodynamics after induction patients were placed in head-up tilt (HUT). All patients became preload responsive as verified by a stroke volume variation (SVV) of > 12%. PE-infusion was then started at 15-20mikrg/min and adjusted until preload was restored (SVV < 12%). Li-dilution cardiac output (CO) was initially measured after induction (baseline), again with HUT in the preload responsive phase, and finally when preload was restored with infusion of PE.At baseline SVV was 10 ± 3% (mean ± st.dev.), CI was 2,6 ± 0,4 L/min*m2, and SVI 43 ± 7mL/m2. With HUT SVV was 19 ± 4%, CI was 2,2 ± 0,4 L/min*m2, SVI 35 ± 7mL/m2. During PE-infusion SVV was reduced to 6 ± 3%, CI increased to 2,6 ± 0,5 L/min*m2, and SVI increased to 49 ± 11mL/m2. All differences p < 0,001. In conclusion: Infusion of phenylephrine during preload dependency increased venous return abolishing preload dependency as evaluated by SVV and increased cardiac stroke volume and -output as measured by indicator-dilution technique. (ClinicalTrials.gov NCT05193097).

Intraoperative haemodynamic monitoring and management of adults having non-cardiac surgery: Guidelines of the German Society of Anaesthesiology and Intensive Care Medicine in collaboration with the German Association of the Scientific Medical Societies

Haemodynamic monitoring and management are cornerstones of perioperative care. The goal of haemodynamic management is to maintain organ function by ensuring adequate perfusion pressure, blood flow, and oxygen delivery. We here present guidelines on "Intraoperative haemodynamic monitoring and management of adults having non-cardiac surgery" that were prepared by 18 experts on behalf of the German Society of Anaesthesiology and Intensive Care Medicine (Deutsche Gesellschaft für Anästhesiologie und lntensivmedizin; DGAI).

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

STUDY REGISTRATION

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

The Use of the Perfusion Index to Predict Post-Induction Hypotension in Patients Undergoing General Anesthesia: A Systematic Review and Meta-Analysis

Post-induction hypotension (PIH) is a common and potentially serious complication of general anesthesia. This meta-analysis (Prospero registration number: CRD42024566321) aimed to evaluate the predictive efficacy of the perfusion index (PI) for PIH in patients undergoing general anesthesia. A comprehensive literature search was performed using multiple electronic databases (Google Scholar, EMBASE, Cochrane Library, and MEDLINE). Studies involving adult patients undergoing general anesthesia, with the PI measured before anesthesia induction and reporting PIH incidence, were included. The primary outcome was the diagnostic accuracy of the PI in predicting the probability of PIH. The secondary outcome was the pooled PIH incidence. Eight studies with 678 patients were included. The pooled incidence of PIH was 44.8% (95% confidence interval [CI]: 29.9%-60.8%). The combined sensitivity and specificity of the PI for predicting PIH were 0.84 (95% CI: 0.65-0.94) and 0.82 (95% CI: 0.70-0.90), respectively. The summary receiver operating characteristic (sROC) analysis revealed an area under curve of 0.89 (95% CI: 0.86-0.92). The Deek's funnel plot asymmetry test indicated no significant publication bias. The PI demonstrates high predictive efficacy for PIH in patients undergoing general anesthesia, indicating that it can be a valuable tool for identifying those at risk of PIH.

Processed electroencephalography-guided general anesthesia and norepinephrine requirements: A randomized trial in patients having vascular surgery

STUDY OBJECTIVE

Processed electroencephalography (pEEG) may help clinicians optimize depth of general anesthesia. Avoiding excessive depth of anesthesia may reduce intraoperative hypotension and the need for vasopressors. We tested the hypothesis that pEEG-guided - compared to non-pEEG-guided - general anesthesia reduces the amount of norepinephrine needed to keep intraoperative mean arterial pressure above 65 mmHg in patients having vascular surgery.

DESIGN

Randomized controlled clinical trial.

SETTING

University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

PATIENTS

110 patients having vascular surgery.

INTERVENTIONS

pEEG-guided general anesthesia.

MEASUREMENTS

Our primary endpoint was the average norepinephrine infusion rate from the beginning of induction of anesthesia until the end of surgery.

MAIN RESULT

96 patients were analyzed. The mean ± standard deviation average norepinephrine infusion rate was 0.08 ± 0.04 μg kg-1 min-1 in patients assigned to pEEG-guided and 0.12 ± 0.09 μg kg-1 min-1 in patients assigned to non-pEEG-guided general anesthesia (mean difference 0.04 μg kg-1 min-1, 95% confidence interval 0.01 to 0.07 μg kg-1 min-1, p = 0.004). Patients assigned to pEEG-guided versus non-pEEG-guided general anesthesia, had a median time-weighted minimum alveolar concentration of 0.7 (0.6, 0.8) versus 0.8 (0.7, 0.8) (p = 0.006) and a median percentage of time Patient State Index was <25 of 12 (1, 41) % versus 23 (3, 49) % (p = 0.279).

CONCLUSION

pEEG-guided - compared to non-pEEG-guided - general anesthesia reduced the amount of norepinephrine needed to keep mean arterial pressure above 65 mmHg by about a third in patients having vascular surgery. Whether reduced intraoperative norepinephrine requirements resulting from pEEG-guided general anesthesia translate into improved patient-centered outcomes remains to be determined in larger trials.

Cardiac index-guided therapy to maintain optimised postinduction cardiac index in high-risk patients having major open abdominal surgery: the multicentre randomised iPEGASUS trial

BACKGROUND

It is unclear whether optimising intraoperative cardiac index can reduce postoperative complications. We tested the hypothesis that maintaining optimised postinduction cardiac index during and for the first 8 h after surgery reduces the incidence of a composite outcome of complications within 28 days after surgery compared with routine care in high-risk patients having elective major open abdominal surgery.

METHODS

In three German and two Spanish centres, high-risk patients having elective major open abdominal surgery were randomised to cardiac index-guided therapy to maintain optimised postinduction cardiac index (cardiac index at which pulse pressure variation was <12%) during and for the first 8 h after surgery using intravenous fluids and dobutamine or to routine care. The primary outcome was the incidence of a composite outcome of moderate or severe complications within 28 days after surgery.

RESULTS

We analysed 318 of 380 enrolled subjects. The composite primary outcome occurred in 84 of 152 subjects (55%) assigned to cardiac index-guided therapy and in 77 of 166 subjects (46%) assigned to routine care (odds ratio: 1.87, 95% confidence interval: 1.03-3.39, P=0.038). Per-protocol analyses confirmed the results of the primary outcome analysis.

CONCLUSIONS

Maintaining optimised postinduction cardiac index during and for the first 8 h after surgery did not reduce, and possibly increased, the incidence of a composite outcome of complications within 28 days after surgery compared with routine care in high-risk patients having elective major open abdominal surgery. Clinicians should not strive to maintain optimised postinduction cardiac index during and after surgery in expectation of reducing complications.

CLINICAL TRIAL REGISTRATION

NCT03021525.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

STUDY REGISTRATION

PROSPERO ( CRD42022316140 ); first submitted 10 March 2022.

Changes in blood catecholamines during induction of general anesthesia in patients with post-induction hypotension undergoing laparoscopic cholecystectomy: A single-center prospective cohort study

BACKGROUND

Post-induction hypotension (PIH) often occurs during general anesthesia induction. This study aimed to investigate blood catecholamine levels during induction of general anesthesia in patients with PIH undergoing laparoscopic cholecystectomy.

METHODS

This prospective study included 557 adult patients who underwent laparoscopic cholecystectomy under general anesthesia. PIH was defined as a greater than 20% decrease in systolic blood pressure from the pre-induction value, a systolic arterial pressure of less than 90 mmHg, or both. Plasma concentrations of epinephrine and norepinephrine during the induction of general anesthesia were determined using enzyme-linked immunosorbent assay. Multivariate logistic regression analysis evaluated the association between the clinical factors and PIH.

RESULTS

Of the 557 patients, 390 had PIH, and the remaining 167 were allocated to the non-PIH group. Changes in blood adrenaline, noradrenaline levels, or both were more pronounced in the PIH than in the non-PIH group (p<0.05). Age, body mass index, a history of hypertension, preoperative systolic blood pressure, and propofol or sufentanil dose were independent predictors of PIH.

CONCLUSION

The changes of blood catecholamines in patients with more stable hemodynamics during the induction of general anesthesia are smaller than that in patients with post-induction hypotension.

TRIAL REGISTRATION

ChiCTR2200055549, 12/01/2022.

Comparison of Ciprofol-Based and Propofol-Based Total Intravenous Anesthesia on Microvascular Decompression of Facial Nerve with Neurophysiological Monitoring: A Randomized Non-Inferiority Trial

Purpose

Ciprofol is a recently developed short-acting gamma-aminobutyric acid receptor agonist with a higher potency than that of propofol. As a new sedative drug, there are few clinical studies on ciprofol. We sought to examine the safety and efficacy of ciprofol use for general anesthesia in neurosurgical individuals undergoing neurosurgical surgery with intraoperative neurophysiological monitoring (IONM).

Patients and Methods

This single-center, non-inferiority, single-blind, randomized controlled trial was conducted from September 13, 2022 to September 22, 2023. 120 patients undergoing elective microvascular decompression surgery (MVD) with IONM were randomly assigned to receive either ciprofol or propofol. The primary outcome of this study was the amplitude of intraoperative compound muscle action potential decline, and the secondary outcome included the indexes related to neurophysiological monitoring and anesthesia outcomes.

Results

The mean values of the primary outcome in the ciprofol group and the propofol group were 64.7±44.1 and 53.4±35.4, respectively. Furthermore, the 95% confidence interval of the difference was -25.78 to 3.12, with the upper limit of the difference being lower than the non-inferiority boundary of 6.6. Ciprofol could achieve non-inferior effectiveness in comparison with propofol in IONM of MVD. The result during anesthesia induction showed that the magnitude of the blood pressure drop and the incidence of injection pain in the ciprofol group were significantly lower than those in the propofol group (P<0.05). The sedative drug and norepinephrine consumption in the ciprofol group was significantly lower than that in the propofol group (P<0.05).

Conclusion

Ciprofol is not inferior to propofol in the effectiveness and safety of IONM and the surgical outcome. Concurrently, ciprofol is more conducive to reducing injection pain and improving hemodynamic stability, which may be more suitable for IONM-related surgery, and has a broad application prospect.

The exploration of perioperative hypotension subtypes: a prospective, single cohort, observational pilot study

Background

Hypotension is a risk factor for postoperative complications, but evidence from randomized trials does not support that a higher blood pressure target always leads to optimized outcomes. The heterogeneity of underlying hemodynamics during hypotension may contribute to these contradictory results. Exploring the subtypes of hypotension can enable optimal management of intraoperative hypotension.

Methods

This is a prospective, observational pilot study. Patients who were ≥ 45 years old and scheduled to undergo moderate-to-high-risk noncardiac surgery were enrolled in this study. The primary objective of this pilot study was to investigate the frequency and distribution of perioperative hypotension and its subtypes (hypotension with or without cardiac output reduction). The exposure of hypotension and its subtypes in patients with and without myocardial or acute kidney injury were also explored.

Results

Sixty patients were included in the analysis. 83% (50/60) of the patients experienced perioperative hypotension. The median duration of hypotension for each patient was 8.0 [interquartile range, 3.1-23.3] minutes. Reduced cardiac output was present during 77% of the hypotension duration. Patients suffering from postoperative myocardial or acute kidney injury displayed longer duration and more extensive exposure in all hypotension subtypes. However, the percentage of different hypotension subtypes did not differ in patients with or without postoperative myocardial or acute kidney injury.

Conclusion

Perioperative hypotension was frequently accompanied by cardiac output reduction in moderate-to-high-risk noncardiac surgical patients. However, due to the pilot nature of this study, the relationship between hypotension subtypes and postoperative myocardial or acute kidney injury still needs further exploration.

Clinical trial registration

https://www.chictr.org.cn/showprojEN.html?proj=134260, CTR2200055929.

Does the choice of induction agent in rapid sequence intubation in the emergency department influence the incidence of post-induction hypotension?

OBJECTIVE

To describe the effects of different induction agents on the incidence of post-induction hypotension (PIH) and its associated interventions during rapid sequence intubation (RSI) in the ED.

METHODS

A single centre retrospective study of patients intubated between 2018 and 2021 was conducted in a regional Australian ED. The impact of induction agent choice, in addition to demographic and clinical factors on the incidence of PIH were determined using descriptive statistics and a multivariate analysis presented as adjusted odds ratios (aORs) and their 95% confidence intervals (CIs).

RESULTS

Ketamine and propofol, used either individually or in conjunction with fentanyl, were significantly associated with PIH (ketamine aOR 4.5, 95% CI 1.35-14.96; propofol aOR 4.88, 95% CI 1.46-16.29). Age >60 years was associated with a greater requirement for vasopressors (aOR 4.46, 95% CI 2.49-7.97) and a higher risk of mortality after RSI (aOR 4.2, 95% CI 1.87-9.40). Patients with a shock index >1.0 were significantly more likely to require vasopressors (aOR 5.13, 95% CI 2.35-11.2) and have a cardiac arrest within 15 min of RSI (aOR 3.56, 95% CI 1.07-11.8).

CONCLUSIONS

Exposure to both propofol and ketamine is significantly associated with PIH after RSI, alongside age and shock index. PIH is likely multifactorial in nature, and this data supports the sympatholytic effect of induction agents as the underlying cause of PIH rather than the choice of agent itself. Further prospective work including a randomised controlled trial between induction agents is justified to further clarify this important clinical question.

Comparison of rocuronium priming vs. standard rapid sequence intubation technique in emergency department patients requiring intubation

OBJECTIVE

In our study, we aimed to compare the effect of standard rapid sequence intubation protocol and the application of rocuronium priming technique on the procedure time and hemodynamic profile.

METHODS

Patients who applied to the emergency department and needed rapid sequence intubation were included in our study, which we conducted with a randomized controlled design. Randomization in the study was made according to the order of arrival of the cases. Rapid sequence intubation was performed in the standard group. In the priming group, 10% of the rocuronium dose was administered approximately 3 min before the induction agent. Intubation time, amount of drug used, vital signs, and end-tidal CO2 level before and after intubation used to confirm intubation were recorded.

RESULTS

A total of 52 patients were included in the study, of which 26 patients were included in the standard group and 26 patients in the priming group. While intubation time was 121.2±21.9 s in the standard group, it was calculated as 68.4±11.6 s in the priming group (p<0.001). While the mean arterial pressure was 58.3±26.6 mmHg in the standard group after intubation, it was 80.6±21.1 mmHg in the priming group (p=0.002).

CONCLUSION

It was observed that priming with rocuronium shortened the intubation time and preserved the hemodynamic profile better.

CLINICAL TRIAL REGISTRATION NUMBER

NCT05343702.

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

Purpose

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

Patients and Methods

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

Results

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

Conclusion

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

Efficacy and safety of ciprofol versus propofol for anesthesia induction in adult patients received elective surgeries: a meta‑analysis

BACKGROUND

Propofol is use widely used in anesthesia, known for its effectiveness, may lead to cardiopulmonary issues in some patients. Ciprofol has emerged as a possible alternative to propofol because it can achieve comparable effects to propofol while causing fewer adverse events at lower doses. However, no definitive conclusion has been reached yet. This meta-analysis aimed to evaluate the efficacy and safety of ciprofol versus propofol in adult patients undergoing elective surgeries under general anesthesia.

METHODS

We searched PubMed, EMBASE, the Cochrane library, Web of Science, and Chinese National Knowledge Infrastructure (CNKI) to identify potentially eligible randomized controlled trials (RCT) comparing ciprofol with propofol in general anesthesia until September 30, 2023. The efficacy outcomes encompassed induction success rate, time to onset of successful induction, time to disappearance of eyelash reflex, and overall estimate means in Bispectral Index (BIS). Safety outcomes were assessed through time to full alertness, incidence of hypotension, incidence of arrhythmia, and incidence of injection-site pain. Continuous variables were expressed as mean difference (MD) with 95% confidence interval (CI), and dichotomous variables were expressed as risk ratio (RR) with 95% CI. Statistical analyses were performed using RevMan 5.4 and STATA 14.0. The quality of the evidence was rated through the grading of recommendations, assessment, development and evaluation (GRADE) system.

RESULTS

A total of 712 patients from 6 RCTs were analyzed. Meta-analysis suggested that ciprofol was equivalent to propofol in terms of successful induction rate, time to onset of successful induction, time to disappearance of eyelash reflex, time to full alertness, and incidence of arrhythmia, while ciprofol was better than propofol in overall estimated mean in BIS (MD: -3.79, 95% CI: -4.57 to -3.01, p < 0.001), incidence of hypotension (RR: 0.63, 95% CI: 0.42 to 0.94, p = 0.02), and incidence of injection-site pain (RR: 0.26, 95% CI: 0.14 to 0.47, p < 0.001). All results were supported by moderate to high evidence.

CONCLUSIONS

Ciprofol may be a promising alternative to propofol because it facilitates achieving a satisfactory anesthesia depth and results in fewer hypotension and injection-site pain. However, we still recommend conducting more studies with large-scale studies to validate our findings because only limited data were accumulated in this study.

TRIAL REGISTRATION

PROSPERO 2023 CRD42023479767.

Prediction of preload dependency using phenylephrine-induced peripheral perfusion index during general anaesthesia: a prospective observational study

BACKGROUND

Tracking preload dependency non-invasively to maintain adequate tissue perfusion in the perioperative period can be challenging.The effect of phenylephrine on stroke volume is dependent upon preload. Changes in stroke volume induced by phenylephrine administration can be used to predict preload dependency. The change in the peripheral perfusion index derived from photoplethysmography signals reportedly corresponds with changes in stroke volume in situations such as body position changes in the operating room. Thus, the peripheral perfusion index can be used as a non-invasive potential alternative to stroke volume to predict preload dependency. Herein, we aimed to determine whether changes in perfusion index induced by the administration of phenylephrine could be used to predict preload dependency.

METHODS

We conducted a prospective single-centre observational study. The haemodynamic parameters and perfusion index were recorded before and 1 and 2 min after administering 0.1 mg of phenylephrine during post-induction hypotension in patients scheduled to undergo surgery. Preload dependency was defined as a stroke volume variation of ≥ 12% before phenylephrine administration at a mean arterial pressure of < 65 mmHg. Patients were divided into four groups according to total peripheral resistance and preload dependency.

RESULTS

Forty-two patients were included in this study. The stroke volume in patients with preload dependency (n = 23) increased after phenylephrine administration. However, phenylephrine administration did not impact the stroke volume in patients without preload dependency (n = 19). The perfusion index decreased regardless of preload dependency. The changes in the perfusion index after phenylephrine administration exhibited low accuracy for predicting preload dependency. Based on subgroup analysis, patients with high total peripheral resistance tended to exhibit increased stroke volume following phenylephrine administration, which was particularly prominent in patients with high total peripheral resistance and preload dependency.

CONCLUSION

The findings of the current study revealed that changes in the perfusion index induced by administering 0.1 mg of phenylephrine could not predict preload dependency. This may be attributed to the different phenylephrine-induced stroke volume patterns observed in patients according to the degree of total peripheral resistance and preload dependency.

TRIAL REGISTRATION

University Hospital Medical Information Network (UMIN000049994 on 9/01/2023).

"The peripheral perfusion index discriminates haemodynamic responses to induction of general anaesthesia"

Induction of general anaesthesia is often accompanied by hypotension. Standard haemodynamic monitoring during anaesthesia relies on intermittent blood pressure and heart rate. Continuous monitoring systemic blood pressure requires invasive or advanced modalities creating a barrier for obtaining important information of the circulation. The Peripheral Perfusion Index (PPI) is obtained non-invasively and continuously by standard photoplethysmography. We hypothesized that different patterns of changes in systemic haemodynamics during induction of general anaesthesia would be reflected in the PPI. Continuous values of PPI, stroke volume (SV), cardiac output (CO), and mean arterial pressure (MAP) were evaluated in 107 patients by either minimally invasive or non-invasive means in a mixed population of surgical patients. 2 min after induction of general anaesthesia relative changes of SV, CO, and MAP was compared to the relative changes of PPI. After induction total cohort mean(± st.dev.) MAP, SV, and CO decreased to 65(± 16)%, 74(± 18)%, and 63(± 16)% of baseline values. In the 38 patients where PPI decreased MAP was 57(± 14)%, SV was 63(± 18)%, and CO was 55(± 18)% of baseline values 2 min after induction. In the 69 patients where PPI increased the corresponding values were MAP 70(± 15)%, SV 80(± 16)%, and CO 68(± 17)% (all differences: p < 0,001). During induction of general anaesthesia changes in PPI discriminated between the degrees of reduction in blood pressure and algorithm derived cardiac stroke volume and -output. As such, the PPI has potential to be a simple and non-invasive indicator of the degree of post-induction haemodynamic changes.

Effect of remimazolam vs. propofol on hemodynamics during general anesthesia induction in elderly patients: Single-center, randomized controlled trial

The current study aimed to compare the effects between remimazolam and propofol on hemodynamic stability during the induction of general anesthesia in elderly patients. We used propofol at a rate of 60 mg/(kg·h) in the propofol group (group P) or remimazolam at a rate of 6 mg/(kg·h) in the remimazolam group (group R) for the induction. A processed electroencephalogram was used to determine whether the induction was successful and when to stop the infusion of the study drug. We measured when patients entered the operating room (T 0), when the induction was successful (T 1), and when before (T 2) and 5 min after successful endotracheal intubation (T 3). We found that mean arterial pressure (MAP) was lower at T 1-3, compared with T 0 in both groups, but higher at T 2 in the group R, while ΔMAP T0-T2 and ΔMAP max were smaller in the group R (ΔMAP T0-T2: the difference between MAP at time point T 0 and T 2, ΔMAP max: the difference between MAP at time point T 0 and the lowest value from T 0 to T 3). Cardiac index and stroke volume index did not differ between groups, whereas systemic vascular resistance index was higher at T 1-3 in the group R. These findings show that remimazolam, compared with propofol, better maintains hemodynamic stability during the induction, which may be attributed to its ability to better maintain systemic vascular resistance levels.

Comparison of different ratios of propofol-ketamine admixture in rapid-sequence induction of anesthesia for emergency laparotomy: a randomized controlled trial

BACKGROUND

We aimed to compare the hemodynamic effect of two ratios of propofol and ketamine (ketofol), namely 1:1 and 1:3 ratios, in rapid-sequence induction of anesthesia for emergency laparotomy.

METHODS

This randomized controlled study included adult patients undergoing emergency laparotomy under general anesthesia. The patients were randomized to receive either ketofol ratio of 1:1 (n = 37) or ketofol ratio of 1:3 (n = 37). Hypotension (mean arterial pressure < 70 mmHg) was managed by 5-mcg norepinephrine. The primary outcome was total norepinephrine requirements during the postinduction period. Secondary outcomes included the incidence of postinduction hypotension, and the intubation condition (excellent, good, or poor).

RESULTS

Thirty-seven patients in the ketofol-1:1 and 35 patients in the ketofol 1:3 group were analyzed. The total norepinephrine requirement was less in the ketofol-1:1 group than in the ketofol-1:3 group, P-values: 0.043. The incidence of postinduction hypotension was less in the ketofol-1:1 group (4 [12%]) than in ketofol-1:3 group (12 [35%]), P-value 0.022. All the included patients had excellent intubation condition.

CONCLUSION

In patients undergoing emergency laparotomy, the use of ketofol in 1:1 ratio for rapid-sequence induction of anesthesia was associated with less incidence of postinduction hypotension and vasopressor consumption in comparison to the 1:3 ratio with comparable intubation conditions.

CLINICAL TRIAL REGISTRATION

NCT05166330. URL: https://clinicaltrials.gov/ct2/show/NCT05166330 .

Monitoring anesthesia depth with patient state index during pediatric surgery

BACKGROUND

Monitoring anesthesia depth in children is challenging. Pediatric anesthesiologists estimate general anesthesia depth using indirect methods such as pharmacokinetic models and neurovegetative reflexes. The application of processed electroencephalography may help to identify the correct anesthesia depth (i.e., patient state index between 25 and 50).

AIMS

To determine the median values of patient state index and spectral edge frequency 95% in children undergoing general anesthesia conducted according to indirect evaluation of depth. The relationships between patient state index and spectral edge frequency 95% and indirect monitoring of anesthesia depth, type of anesthesia, age subgroups, and postoperative delirium were also assessed.

METHODS

A prospective observational study on children (aged 1-18 years) undergoing surgery longer than 60 min. The SedLine monitor and the novel SedLine pediatric sensors (Masimo Inc., Irvine California) were applied. Patient state index levels were recorded for the duration of the anesthesia until the discharge to the ward at predefined time points.

RESULTS

In the 111 enrolled children, median patient state index level at the end of anesthesia induction was 25 (22-32) and ranged from 26 (23-34) to 28 (25-36) in the maintenance phase. Patient state index at extubation was 48 (35-60) and 69 (62-75) at discharge from the operatory room. Median right/left spectral edge frequency 95% values at the end of induction were 10 (6-14)/9 (5-14) Hz and median right/left spectral edge frequency 95% values in the maintenance phase ranged from 10 (6-14) to 12 (11-15) Hz in both hemispheres. At extubation, right/left spectral edge frequency 95% levels were 18 (15-21)/17 (15-21) Hz. We observed 39 episodes of burst suppression in 20 patients (19%). Median patient state index levels were not different between patients undergoing inhalational and intravenous anesthesia and between those undergoing general anesthesia and general anesthesia added to locoregional anesthesia. Children <2 years displayed significantly higher patient state index levels than older patients (p = .0004). The presence of a burst suppression episode was not associated with PAED levels (OR 1.58, 95% CI 0.14-16.74, p` = .18).

CONCLUSIONS

NonpEEG-guided anesthesia in children led to median patient state index levels at the low range of recommended unconsciousness values with frequent episodes of burst suppression. Patient state index levels were generally higher in children below 2 years.

Paralysis Versus Non-Paralysis Anesthesia for Operative Laryngoscopy: A Randomized Controlled Trial

OBJECTIVE

To compare outcomes between two standard-of-care anesthesia regimens for operative laryngoscopy: general anesthesia with a neuromuscular blocking agent (NMBA) versus remifentanil and propofol (non-NMBA).

METHODS

This was a prospective, single-blinded, randomized controlled trial at a tertiary care center. Patients were randomized to either anesthesia using rocuronium (NMBA) or with remifentanil/propofol infusion alone (non-NMBA). Intraoperative impressions, anesthesia data, and post-operative patient surveys were collected.

RESULTS

Sixty-one patients who underwent suspension laryngoscopy from 2020 to 2022 were included (25 female, 36 male, ranging 20-81 years). Thirty patients were enrolled in the NMBA arm and 31 patients in the non-NMBA arm. Heart rate and mean arterial pressure were higher in the NMBA (p < 0.01). Patients in the non-NMBA group were more likely to require vasopressors (p = 0.04, RR = 3.08 [0.86-11.05]). Surgeons were more frequently satisfied with conditions in the NMBA group (86.7%) compared to the non-NMBA group (58.1%, p < 0.01). Procedures were more likely to be paused due to movement in the non-NMBA group (45.1%) compared to the NMBA group (16.6%, p < 0.03, RR = 2.26 [1.02-4.99]). Patients in the non-NMBA group were more likely to endorse myalgia the week after surgery (44%) compared to the NMBA group (8.3%, p < 0.01) and reported higher average pain levels on a 0-10 pain scale (3.7) compared to the paralysis group (2.0).

CONCLUSIONS

Anesthesia with rocuronium was associated with better intraoperative conditions and postoperative pain compared to anesthesia with remifentanil/propofol. Remifentanil/propofol were associated with lower blood pressure and suppression of laryngoscopy-associated tachycardia.

LEVEL OF EVIDENCE

2 Laryngoscope, 133:2654-2664, 2023.

Blood pressure control with phenylephrine or dobutamine: a randomized controlled trial comparing effects on cerebral and paravertebral tissue oxygen saturation measured with near-infrared spectroscopy

Preserving haemodynamics is expected to positively affect tissue oxygen saturation. We hypothesized that maintaining mean arterial blood pressure (MAP) (using phenylephrine (PE) or dobutamine (Dobu)) would equally affect regional cerebral and paravertebral tissue saturation (rScO2 and rSpvO2, respectively). Thirty-four patients were randomly assigned to receive either PE or Dobu, in order to keep MAP within 20% of the preoperative value. Their effect on haemodynamics, rScO2 and rSpvO2 at thoracic level T3-T4, T9-T10 and lumbar level L1-L2 was calculated at different doses. Drug-induced haemodynamic effects differed between groups (∆MAP: -2%±21 and - 19%±17, ∆CI: -14.6%±14.6 and 24.1%±49.9, ∆HR: -21%±21 and 0%±16 for PE and Dobu, respectively). Both groups exhibited a significant decrease in rScO2, with a more pronounced decline in the PE group (-14.1%±16.1) compared to the Dobu group (-5.9%±10.6). There were no significant changes at the paravertebral level in either group, but a slight but statistically significant difference was detected between the two groups at T3-T4 and L1-L2. Current guidelines advocate maintaining adequate systemic blood pressures to prevent spinal cord ischaemia in specific procedures. However, it is still unknown which circulatory supportive drug is more beneficial for maintaining spinal cord perfusion. Our data indicates that, when used for maintenance of blood pressure within a 20% range of preoperative values, neither phenylephrine nor dobutamine affect paravertebral tissue saturation.

Remimazolam vs Etomidate: Haemodynamic Effects in Hypertensive Elderly Patients Undergoing Non-Cardiac Surgery

Background

Remimazolam tosilate (RT) is a novel ultrashort-acting γ-aminobutyric acid subtype A (GABAA) agonist, with several advantages including rapid induction and recovery, stable haemodynamics, and mild respiratory inhibition. However, studies have not been conducted to explore the haemodynamic effects of RT in elderly hypertensive subjects undergoing non-cardiac surgery. Therefore, we sought to compare the effects of anaesthesia induction using different doses of RT and etomidate on the haemodynamics of this group of patients.

Methods

Patients were recruited into this single-center, prospective, randomized, double-blind trial from October 2022 to June 2023. A total of 150 hypertensive elderly undergoing non-cardiac surgery were randomly assigned into 0.2 mg/kg RT group (Group RL), 0.3 mg/kg RT group (Group RH) and 0.3 mg/kg etomidate group (Group E). The primary outcome of the study was haemodynamic changes (mean arterial pressure fluctuation value -∆MAP and heart rate fluctuation value -∆HR) observed during anaesthesia induction. Secondary outcomes included incidence of adverse cardiovascular events and adverse drug reactions (injection pain and myoclonus), cumulative doses of vasoactive drugs and vital signs at different time points.

Results

Patients in Group E and Group RL had significantly lower haemodynamic fluctuations (∆MAP), lower incidence of hypotension and cumulative dose of ephedrine than subjects in Group RH. Patients in groups RL and RH had significantly lower incidence of injection pain and myoclonus compared with patients in group E. The results showed no statistically significant differences in ∆HR, hypertension, bradycardia, tachycardia, and time to loss of eye-opening reflex and start of intubation, and vital signs at different time points among the three groups.

Conclusion

Use of low-dose RT (0.2 mg/kg) for induction of non-cardiac surgical anaesthesia in elderly hypertensive patients is more effective in maintaining haemodynamic stability and has fewer adverse effects compared with etomidate.

Hypotension after Anesthesia Induction: Target-Controlled Infusion Versus Manual Anesthesia Induction of Propofol

BACKGROUND

Post-induction hypotension frequently occurs and can lead to adverse outcomes. As target-controlled infusion (TCI) obviates the need to calculate the infusion rate manually and helps safer dosing with prompt titration of the drug using complex pharmacokinetic models, the use of TCI may provide a better hemodynamic profile during anesthesia induction. This study aimed to compare TCI versus manual induction and to determine the hemodynamic risk factors for post-induction hypotension.

METHODS

A total of 200 ASA grade 1-3 patients, aged 24 to 82 years, were recruited and randomly assigned to the TCI (n = 100) or manual induction groups (n = 100). Hemodynamic parameters were monitored with the pressure-recording analytic method. The propofol dosage was adjusted to keep the Bispectral Index between 40 and 60.

RESULTS

Post-induction hypotension was significantly higher in the manual induction group than in the TCI group (34% vs. 13%; p < 0.001, respectively). The propofol induction dose did not differ between the groups (TCI: 155 (135-180) mg; manual: 150 (120-200) mg; p = 0.719), but the induction time was significantly longer in the TCI group (47 (35-60) s vs. 150 (105-220) s; p < 0.001, respectively). In the multivariable Cox regression model, the presence of hypertension, stroke volume index (SVI), cardiac power output (CPO), and anesthesia induction method were found to predict post-induction hypotension (p = 0.032, p = 0.013, p = 0.024, and p = 0.015, respectively).

CONCLUSION

TCI induction with propofol provided better hemodynamic stability than manual induction, and the presence of hypertension, a decrease in the pre-induction SVI, and the CPO could predict post-induction hypotension.

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

STUDY OBJECTIVE

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

DESIGN

Prospective observational study.

PATIENTS

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

MEASUREMENTS

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

MAIN RESULTS

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

CONCLUSION

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

The effect of intravenous granisetron on prophylactic ephedrine for preventing hypotension after general anaesthesia induction in elderly patients: a randomized controlled trial

Serotonin 3 receptor antagonists, a commonly used drug for preventing postoperative nausea and vomiting, have recently been reported to decrease the incidence of hypotension and the need for vasoactive drugs after spinal anaesthesia in obstetric surgery. However, it remains unknown whether they could also prevent hypotension after induction of general anaesthesia. In the current study, we aimed to investigate the effect of intravenous granisetron on prophylactic ephedrine for preventing hypotension after general anaesthesia induction in elderly patients. Sixty elderly patients were randomly assigned to receive granisetron or saline control 30 min before induction of general anaesthesia. The first patient in each group received a prophylactic dose of ephedrine (0.15 mg kg^-1) to prevent hypotension. The prophylactic dose for each patient was increased or decreased by 0.05 mg/kg based on the efficacy results of the previous patient. The up-down sequential allocation analysis and probit regression was used to calculate the effective dose for 50% of patients (ED50) with prophylactic ephedrine. In the up-down sequential allocation analysis, the ED50 of ephedrine was significantly lower in group granisetron (0.08 mg kg^-1 [95% CI, 0.06-0.11 mg kg^-1]) when compared with group control (0.14 mg kg^-1 [95% CI, 0.13-0.16 mg kg^-1]) (P < 0.001). The conclusion was further supported by probit regression analysis (0.09 mg kg^-1 [95% CI, 0.05-0.12 mg kg^-1] in group granisetron and 0.14 mg kg^-1 [95% CI, 0.12-0.16 mg kg^-1] in group control). Intravenous granisetron reduced the requirement of prophylactic ephedrine in preventing hypotension after general anaesthesia induction in elderly patients.

Continuous Blood Pressure Monitoring in Patients Having Surgery: A Narrative Review

Hypotension can occur before, during, and after surgery and is associated with postoperative complications. Anesthesiologists should thus avoid profound and prolonged hypotension. A crucial part of avoiding hypotension is accurate and tight blood pressure monitoring. In this narrative review, we briefly describe methods for continuous blood pressure monitoring, discuss current evidence for continuous blood pressure monitoring in patients having surgery to reduce perioperative hypotension, and expand on future directions and innovations in this field. In summary, continuous blood pressure monitoring with arterial catheters or noninvasive sensors enables clinicians to detect and treat hypotension immediately. Furthermore, advanced hemodynamic monitoring technologies and artificial intelligence-in combination with continuous blood pressure monitoring-may help clinicians identify underlying causes of hypotension or even predict hypotension before it occurs.

ERCP-related adverse events: incidence, mechanisms, risk factors, prevention, and management

INTRODUCTION

Endoscopic retrograde cholangiopancreatography (ERCP) is a commonly performed procedure for pancreaticobiliary disease. While ERCP is highly effective, it is also associated with the highest adverse event (AE) rates of all commonly performed endoscopic procedures. Thus, it is critical that endoscopists and caregivers of patients undergoing ERCP have clear understandings of ERCP-related AEs.

AREAS COVERED

This narrative review provides a comprehensive overview of the available evidence on ERCP-related AEs. For the purposes of this review, we subdivide the presentation of each ERCP-related AE according to the following clinically relevant domains: definitions and incidence, proposed mechanisms, risk factors, prevention, and recognition and management. The evidence informing this review was derived in part from a search of the electronic databases PubMed, Embase, and Cochrane, performed on 1 May 20231 May 2023.

EXPERT OPINION

Knowledge of ERCP-related AEs is critical not only given potential improvements in peri-procedural quality and related care that can ensue but also given the importance of reviewing these considerations with patients during informed consent. The ERCP community and researchers should aim to apply standardized definitions of AEs. Evidence-based knowledge of ERCP risk factors should inform patient care decisions during training and beyond.

Post-induction hypotension with remimazolam versus propofol in patients routinely administered angiotensin axis blockades: a randomized control trial

BACKGROUND

Certain routine medication could result in post-induction hypotension (PIH), such as angiotensin axis blockades, which are frequently administered as a first-line therapy against hypertension. Remimazolam is reportedly associated with lesser intraoperative hypotension than propofol. This study compared the overall incidence of PIH following remimazolam or propofol administration in patients managed by angiotensin axis blockades.

METHODS

This single-blind, parallel-group, randomized control trial was conducted in a tertiary university hospital in South Korea. Patients undergoing surgery with general anesthesia were considered for enrollment if the inclusion criteria were met: administration of an angiotensin converting enzyme inhibitor or angiotensin receptor blocker, 19 to 65 years old, American Society of Anesthesiologists physical status classification ≤ III, and no involvement in other clinical trials. The primary outcome was the overall incidence of PIH, defined as a mean blood pressure (MBP) < 65 mmHg or decrease by ≥ 30% of the baseline MBP. The time points of measurement were baseline, just before the initial intubation attempt, and 1, 5, 10, and 15 min following intubation. The heart rate, systolic and diastolic blood pressures, and bispectral index were also recorded. Groups P and R included patients administered propofol and remimazolam, respectively, as an induction agent.

RESULTS

A total of 81 patients were analyzed, of the 82 randomized patients. PIH was less frequent in group R than group P (62.5% versus 82.9%; t value 4.27, P = 0.04, adjusted odds ratio = 0.32 [95% confidence interval 0.10-0.99]). The decrease in the MBP from baseline was 9.6 mmHg lesser in group R than in group P before the initial intubation attempt (95% confidence interval 3.3-15.9). A similar trend was observed for systolic and diastolic blood pressures. No severe adverse events were observed in either group.

CONCLUSION

Remimazolam results in less frequent PIH than propofol in patients undergoing routine administration of angiotensin axis blockades.

TRIAL REGISTRATION

This trial was retrospectively registered on Clinical Research Information Service (CRIS), Republic of Korea (KCT0007488). Registration date: 30/06/2022.

Effects of Different Injection Rates of Propofol on Postoperative Cognition in Elderly Patients Undergoing Laparoscopic Inguinal Hernia Repair

Purpose

This study aimed to explore the effects of different injection rates of propofol on postoperative cognition in elderly patients undergoing laparoscopic inguinal hernia repair.

Methods

A total of 180 elderly patients who planned to undergo laparoscopic inguinal hernia repair were randomly divided into three groups: slow injection of propofol (V_S-Group, 30 mg kg^-1 h^-1); medium injection of propofol (V_M-Group, 100 mg kg^-1 h^-1) or fast injection of propofol (V_F-Group, 300 mg kg^-1 h^-1). Propofol was induced by microinfusion pump, and the depth of anesthesia was monitored by bispectral index (BIS). Propofol and remifentanil were continuously infused during anesthesia maintenance and adjusted according to BIS. The primary outcome was the use of the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) to measure the incidence of postoperative cognitive decline (POCD) in elderly patients on the first and seventh postoperative day. Secondary outcomes included induced dose of propofol, incidence of burst suppression and maximum electroencephalographic (EEG) effect of propofol (BIS-min) during induction.

Results

The incidence of POCD on the first and seventh day postoperatively was similar among the three groups (P > 0.05). However, with the increase of propofol injection rate, induced dose of propofol, incidence of burst suppression and BIS-min during induction, the number of patients requiring vasoactive agents were significantly increased (P < 0.001). Multivariate regression analysis showed that the brief duration of burst suppression during induction did not affect the occurrence of POCD, while age and duration of hospitalization were risk factors for POCD.

Conclusion

For elderly patients undergoing laparoscopic inguinal hernia repair, lowering the injection rate of propofol (such as 30 mg kg^-1 h^-1) cannot decrease the incidence of early POCD, but reduces induction dose of propofol and use of vasoactive drugs, making the patient's hemodynamics more stable.

Intraoperative hypotension when using hypotension prediction index software during major noncardiac surgery: a European multicentre prospective observational registry (EU HYPROTECT)

Background

Intraoperative hypotension is associated with organ injury. Current intraoperative arterial pressure management is mainly reactive. Predictive haemodynamic monitoring may help clinicians reduce intraoperative hypotension. The Acumen™ Hypotension Prediction Index software (HPI-software) (Edwards Lifesciences, Irvine, CA, USA) was developed to predict hypotension. We built up the European multicentre, prospective, observational EU HYPROTECT Registry to describe the incidence, duration, and severity of intraoperative hypotension when using HPI-software monitoring in patients having noncardiac surgery.

Methods

We enrolled 749 patients having elective major noncardiac surgery in 12 medical centres in five European countries. Patients were monitored using the HPI-software. We quantified hypotension using the time-weighted average MAP <65 mm Hg (primary endpoint), the proportion of patients with at least one ≥1 min episode of a MAP <65 mm Hg, the number of ≥1 min episodes of a MAP <65 mm Hg, and duration patients spent below a MAP of 65 mm Hg.

Results

We included 702 patients in the final analysis. The median time-weighted average MAP <65 mm Hg was 0.03 (0.00-0.20) mm Hg. In addition, 285 patients (41%) had no ≥1 min episode of a MAP <65 mm Hg; 417 patients (59%) had at least one. The median number of ≥1 min episodes of a MAP <65 mm Hg was 1 (0-3). Patients spent a median of 2 (0-9) min below a MAP of 65 mm Hg.

Conclusions

The median time-weighted average MAP <65 mm Hg was very low in patients in this registry. This suggests that using HPI-software monitoring may help reduce the duration and severity of intraoperative hypotension in patients having noncardiac surgery.

Hemodynamic effects of intraoperative 30% versus 80% oxygen concentrations: an exploratory analysis

Background

Supplemental oxygen leads to an increase in peripheral vascular resistance which finally increases systemic blood pressure in healthy subjects and patients with coronary artery disease, heart failure, undergoing heart surgery, and with sepsis. However, it is unknown whether this effect can also be observed in anesthetized patients having surgery. Thus, we evaluated in this exploratory analysis of a randomized controlled trial the effect of 80% versus 30% oxygen on intraoperative blood pressure and heart rate.

Methods

We present data from a previous study including 258 patients, who were randomized to a perioperative inspiratory FiO₂ of 0.8 (128 patients) versus 0.3 (130 patients) for major abdominal surgery. Continuous arterial blood pressure values were recorded every three seconds and were exported from the electronic anesthesia record system. We calculated time-weighted average (TWA) and Average Real Variability (ARV) of mean arterial blood pressure and of heart rate.

Results

There was no significant difference in TWA of mean arterial pressure between the 80% (80 mmHg [76, 85]) and 30% (81 mmHg [77, 86]) oxygen group (effect estimate -0.16 mmHg, CI -1.83 to 1.51; p = 0.85). There was also no significant difference in TWA of heart rate between the 80 and 30% oxygen group (median TWA of heart rate in the 80% oxygen group: 65 beats.min^-1 [58, 72], and in the 30% oxygen group: 64 beats.min^-1 [58; 70]; effect estimate: 0.12 beats.min^-1, CI -2.55 to 2.8, p = 0.94). Also for ARV values, no significant differences between groups could be detected.

Conclusion

In contrast to previous results, we did not observe a significant increase in blood pressure or a significant decrease in heart rate in patients, who received 80% oxygen as compared to patients, who received 30% oxygen during surgery and for the first two postoperative hours. Thus, hemodynamic effects of supplemental oxygen might play a negligible role in anesthetized patients.

Clinical Trail Registration

https://clinicaltrials.gov/ct2/show/NCT03366857?term=vienna&cond=oxygen&draw=2&rank=1.

Hypotension Prediction Index guided Goal Directed therapy and the amount of Hypotension during Major Gynaecologic Oncologic Surgery: a Randomized Controlled clinical Trial

Intraoperative hypotension (IOH) is associated with increased morbidity and mortality. Hypotension Prediction Index (HPI) is a machine learning derived algorithm that predicts IOH shortly before it occurs. We tested the hypothesis that the application of the HPI in combination with a pre-defined Goal Directed Therapy (GDT) hemodynamic protocol reduces IOH during major gynaecologic oncologic surgery. We enrolled women scheduled for major gynaecologic oncologic surgery under general anesthesia with invasive arterial pressure monitoring. Patients were randomized to a GDT protocol aimed at optimizing stroke volume index (SVI) or hemodynamic management based on HPI guidance in addition to GDT. The primary outcome was the amount of IOH, defined as the timeweighted average (TWA) mean arterial pressure (MAP) < 65 mmHg. Secondary outcome was the TWA-MAP < 65 mmHg during the first 20 min after induction of GA. After exclusion of 10 patients the final analysis included 60 patients (30 in each group). The median (25-75th IQR) TWA-MAP < 65 mmHg was 0.14 (0.04-0.66) mmHg in HPI group versus 0.77 (0.36-1.30) mmHg in Control group, P < 0.001. During the first 20 min after induction of GA, the median TWA-MAP < 65 mmHg was 0.53 (0.06-1.8) mmHg in the HPI group and 2.15 (0.65-4.2) mmHg in the Control group, P = 0.001. Compared to a GDT protocol aimed to SVI optimization, a machine learning-derived algorithm for prediction of IOH combined with a GDT hemodynamic protocol, reduced IOH and hypotension after induction of general anesthesia in patients undergoing major gynaecologic oncologic surgery.Trial registration number: NCT04547491. Date of registration: 10/09/2020.

Endotypes of intraoperative hypotension during major abdominal surgery: a retrospective machine learning analysis of an observational cohort study

BACKGROUND

Intraoperative hypotension is associated with myocardial injury, acute kidney injury, and death. In routine practice, specific causes of intraoperative hypotension are often unclear. A more detailed understanding of underlying haemodynamic alterations of intraoperative hypotension may identify specific treatments. We thus aimed to use machine learning - specifically, hierarchical clustering - to identify underlying haemodynamic alterations causing intraoperative hypotension in major abdominal surgery patients. Specifically, we tested the hypothesis that there are distinct endotypes of intraoperative hypotension, which may help refine therapeutic interventions.

METHODS

We conducted a secondary analysis of intraoperative haemodynamic measurements from a prospective observational study in 100 patients who had major abdominal surgery under general anaesthesia. We used stroke volume index, heart rate, cardiac index, systemic vascular resistance index, and pulse pressure variation measurements. Intraoperative hypotension was defined as any mean arterial pressure ≤65 mm Hg or a mean arterial pressure between 66 and 75 mm Hg requiring a norepinephrine infusion rate exceeding 0.1 μg kg^-1 min^-1. To identify endotypes of intraoperative hypotension, we used hierarchical clustering (Ward's method).

RESULTS

A total of 615 episodes of intraoperative hypotension occurred in 82 patients (46 [56%] female; median age: 64 [57, 73] yr) who had surgery of a median duration of 270 (195, 335) min. Hierarchical clustering revealed six distinct intraoperative hypotension endotypes. Based on their clinical characteristics, we labelled these endotypes as (1) myocardial depression, (2) bradycardia, (3) vasodilation with cardiac index increase, (4) vasodilation without cardiac index increase, (5) hypovolaemia, and (6) mixed type.

CONCLUSION

Hierarchical clustering identified six endotypes of intraoperative hypotension. If validated, considering these intraoperative hypotension endotypes may enable causal treatment of intraoperative hypotension.

Efficacy and safety of HSK3486 vs. propofol for the induction and maintenance of general anaesthesia: A multicentre, single-blind, randomised, parallel-group, phase 3 clinical trial

BACKGROUND

HSK3486 (ciprofol) is a 2,6-disubstituted phenol derivative that acts like propofol as an agonist at the gamma-aminobutyric acid-A (GABA A ) receptor.

OBJECTIVE

To investigate the efficacy and safety of HSK3486 for general anaesthesia induction and maintenance.

DESIGN

A single-blinded, randomised, parallel-group, phase 3 trial.

SETTING

Involving 10 study centres, from November 24, 2020 to January 25, 2021.

PATIENTS

A total of 129 patients undergoing nonemergency, noncardiothoracic, and nonbrain elective surgery.

INTERVENTION

Patients were randomly assigned at a 2:1 ratio into HSK3486 or propofol groups, to receive HSK3486 (0.4 mg kg -1 ) or propofol (2.0 mg kg -1 ) for induction before a maintenance infusion at initial rates of 0.8 and 5.0 mg kg -1 h -1 , and were adjusted to maintain a bispectral index (BIS) of 40-60 until the end of surgery.

MAIN OUTCOME MEASURES

Noninferiority between the drugs was evaluated as the lower limit of the 95% confidence interval (CI) for the between-group difference in the success rate of anesthetic maintenance (primary outcome) >-8%. Secondary outcomes included successful anaesthetic induction, full alertness and spontaneous breathing recovery, time until leaving the postanaesthesia care unit and changes in BIS. Safety profiles were also measured.

RESULTS

Of 129 enrolled patients, 128 completed the trial, with 86 in the HSK3486 group and 42 in the propofol group. The success rate for the maintenance of general anaesthesia was 100% for both groups, and noninferiority of HSK3486 was confirmed (95% CI -4.28% to 8.38%). No significant differences were found between the two groups of patients with regard to secondary outcomes (all P  > 0.05). There appeared to be a comparable incidence of treatment for emergency adverse events (TEAEs) (80.2% vs. 81.0%, P  = 1.000) and drug-related TEAEs (57.0% vs. 64.3%, P  = 0.451) in the HSK3486 and propofol groups.

CONCLUSION

HSK3486 had a noninferior efficacy profile compared to propofol, exhibiting excellent tolerance.

TRIAL REGISTRATION

Clinicaltrials.gov, identifier: NCT04511728.

Clinical observation of different dosages of dexmedetomidine combined with a target-controlled infusion of propofol in hysteroscopic submucosal myomectomy

Objective

This study aimed to explore the clinical effects of different dosages of dexmedetomidine (Dex) combined with a target-controlled infusion of propofol in hysteroscopic submucosal myomectomy.

Methods

Ninety patients who underwent hysteroscopic submucosal myomectomy between September 2021 and March 2022 were enrolled and randomly divided into three groups, with 30 patients in each group. Patients in Groups A, B, and C received injections of 0.25, 0.5, or 0.75 µg/kg of Dex, respectively, by intravenous pump over 10 min. After this time, a maintenance dosage of 0.5 µg/kg/h was administered by intravenous infusion until the end of the surgery. Anesthesia was induced using 1.5 mg/kg of propofol and 0.3 µg/kg of sufentanil that were introduced through a laryngeal mask. The plasma concentration of propofol was maintained at 3 µg/ml by target-controlled infusion until the end of the surgery. The mean arterial pressure (MAP), heart rate (HR), and electroencephalographic bispectral index (BIS) were observed when the patient entered the operating room (T0), after catheter indwelling for anesthesia (T1), at the time of cervical dilation (T2), at the time of hysteroscopic surgery (T3), and at the end of the surgery (T4) in all three groups. The total dosage of propofol for induction and maintenance, anesthesia awakening time, orientation recovery time, Visual Analog Scale (VAS) score of the post-awakening uterine contraction pain, and adverse reactions were recorded.

Results

The intraoperative reductions of MAP and HR in patients were significant in Group C when compared with those in Groups A and B (P < 0.05), and BIS was significantly lower in Group C at T2 and T3 when compared with the baseline measurement at T0 (P < 0.05). The dosage of propofol was significantly higher for Group A than for Groups B and C (P < 0.05). The anesthesia awakening time and orientation recovery time were significantly longer for patients in Group C when compared with patients in Groups A and B (P < 0.05). Within 5-30 min after awakening, the VAS scores in Groups B and C were significantly lower than those for Group A (P < 0.05). The incidence of adverse reactions in Group B was significantly less than that for Groups A and C (P < 0.05).

Conclusion

The continuous pumping of 0.5 µg/kg of Dex combined with a target-controlled infusion of propofol in hysteroscopic submucosal myomectomy resulted in positive anesthetic and analgesia effects and fewer adverse reactions. It therefore has high clinical significance.

The Perfusion Index of the Ear as a Predictor of Hypotension Following the Induction of Anesthesia in Patients with Hypertension: A Prospective Observational Study

Patients with hypertension develop hemodynamic instability more frequently during anesthesia-particularly post-induction. Therefore, different monitoring methods may be required in patients with hypertension. Perfusion index-the ratio of the pulsatile blood flow to the non-pulsatile static blood flow in a patient's peripheral tissues, such as the fingers or ears-can show the hemodynamic status of the patient in a non-invasive way. Among the sites used for measuring the perfusion index, it is assumed that the ear is more reliable than the finger for hemodynamic monitoring, because proximity to the brain ensures appropriate perfusion. We hypothesized that the low value of preoperative ear PI could be a predictor of post-induction hypotension in patients with hypertension. Thirty patients with hypertension were enrolled. The perfusion index and pleth variability index were measured using the ear, finger, and blood pressure, and heart rate was recorded to monitor hypotension. After insertion of the supraglottic airway, 20 patients developed post-induction hypotension. Those who developed hypotension showed a significantly lower preoperative perfusion index of the ear. The preoperative perfusion index of the ear could predict post-induction hypotension in patients with hypertension.

Effect of different doses of esketamine compared with fentanyl combined with propofol on hypotension in patients undergoing painless abortion surgery: a prospective, randomized, double-blind controlled clinical trial

Background

Opioids analgesics commonly used in abortion procedures are associated with respiratory and circulatory depression. Esketamine is a N-methyl-D-aspartate receptor (NMDA) antagonist and a common analgesic. The drug has several advantages including rapid onset and offset and it causes minimal cardiorespiratory depression. However, studies have not explored the effects of esketamine in patients undergoing painless abortion surgery. Therefore, the present study sought to evaluate the effect of different doses of esketamine compared with the effect of fentanyl on incidence of perioperative hypotension in patients undergoing painless abortion surgery and to explore the optimal esketamine dose for this population.

Methods

A total of 178 female patients undergoing painless abortion surgery were enrolled to the current study. The patients were aged 18–45 years, had a body mass index (BMI) of 18–28 kg m^− 2 and a class I or II physical status as determined using the American Society of Anesthesiologists (ASA) system. Patients were randomly assigned to four groups as follows: group F (n = 45) in which patients underwent intravenous (IV) administration of 1 μg kg^− 1 fentanyl followed by IV administration of 2 mg kg^− 1 propofol, and group EL, group EM and group EH (n = 45, 44, 44) with patients receiving IV administration of 0.2 mg kg^− 1, 0.25 mg kg^− 1, 0.3 mg kg^− 1 esketamine, respectively, followed by IV administration of 2 mg kg^− 1 propofol. The primary outcome of the study was the incidence of hypotension whereas secondary outcomes included incidence of adverse events, perioperative changes of vital signs, anesthesia induction time, recovery time and dischargeable time, propofol addition, as well as patient, surgeon and anesthesiologist satisfaction levels.

Results

The findings showed that the incidence of hypotension was significantly lower in subjects in group EL, group EM and group EH (0, 0, 0%) relative to the incidence in patients in group F (20%) (χ² = 19.648; P = 0.000). In this study, the incidence of hypoxia of subjects in group EL, group EM and group EH (0, 2.3, 2.3%) was significantly lower compared with that of patients in group F (11.1%) (χ² = 8.622; P = 0.035). The findings indicated that the incidence of somatic motor reactions was significantly lower in participants in group EM and group EH (9.1, 4.5%) relative to that of patients in group F and group EL (26.7, 15.6%) (χ² = 10.254; P = 0.016). The results showed that the incidence of nausea and vomiting and potential psychiatric symptoms were significantly higher in patients in group EH (15.9, 11.4%) compared with that of participants in group F (2.2, 0%), group EL (4.4, 0%) and group EM (2.3, 2.3%) (χ² = 7.493; P = 0.038 and χ² = 8.248; P = 0.003). In this study, the mean arterial pressure (MAP) and heart rate (HR) of subjects in group EL, group EM and group EH were more stable compared with that of patients in group F. Frequency of the additional propofol dose was markedly less in group EM and EH (26.7%, 17,8%) compared with that in group F and EL (9.1, 4.5%) (χ² = 10.254; P = 0.016). The findings indicated that the dischargeable time was significantly shorter for patients in group EM compared with that of subjects in group F, group EL and group EH.

Conclusions

The findings of the present study showed that single-dose esketamine (0.25 mg kg^− 1) effectively decreased incidence of hypotension and total adverse events and reduced the frequency of additional propofol dose required for patients undergoing painless abortion with preservation of physician-patient satisfaction.

Continuous intra-arterial versus intermittent oscillometric arterial pressure monitoring and hypotension during induction of anaesthesia: the AWAKE randomised trial

BACKGROUND

Hypotension during induction of anaesthesia is associated with organ injury. Continuous arterial pressure monitoring might help reduce hypotension. We tested the hypothesis that continuous intra-arterial compared with intermittent oscillometric arterial pressure monitoring reduces hypotension during induction of anaesthesia in noncardiac surgery patients.

METHODS

In this single-centre randomised trial, 242 noncardiac surgery patients in whom intra-arterial arterial pressure monitoring was planned were randomised to unblinded continuous intra-arterial or to intermittent oscillometric arterial pressure monitoring (with blinded intra-arterial arterial pressure monitoring) during induction of anaesthesia. The primary endpoint was the area under a mean arterial pressure (MAP) of 65 mm Hg within the first 15 min of induction of anaesthesia. Secondary endpoints included areas under MAP values of 60, 50, and 40 mm Hg and durations of MAP values <65, <60, <50, and <40 mm Hg.

RESULTS

There were 224 subjects available for analysis. The median (25th-75th percentile) area under a MAP of 65 mm Hg was 15 (2-36) mm Hg • min in subjects assigned to continuous intra-arterial monitoring and 46 (7-111) mm Hg • min in subjects assigned to intermittent oscillometric monitoring (P<0.001). Subjects assigned to continuous intra-arterial monitoring had smaller areas under MAP values of 60, 50, and 40 mm Hg and shorter durations of MAP values <65, <60, <50, and <40 mm Hg than subjects assigned to intermittent oscillometric monitoring.

CONCLUSION

Continuous intra-arterial arterial pressure monitoring reduces hypotension during induction of anaesthesia compared with intermittent oscillometric arterial pressure monitoring in noncardiac surgery patients. In patients for whom an arterial catheter is planned, clinicians might therefore consider inserting the arterial catheter before rather than after induction of anaesthesia.

CLINICAL TRIALS REGISTRATION

NCT04894019.

Effect of Preanesthetic Fluid Loading on Postinduction Hypotension and Advanced Cardiac Parameters in Patients with Chronic Compressive Cervical Myelopathy: A Randomized Controlled Trial

Purpose  Hypotension during the early intraoperative phase is common and can lead to adverse perioperative outcomes. Fluid preloading is one of the methods to limit its occurrence. Patients with chronic compressive cervical myelopathy may have autonomic dysfunction, which can aggravate hemodynamic alterations during anesthesia. This study compared the occurrence of postinduction hypotension and changes in cardiac dynamic indices in patients with and without crystalloid preloading undergoing decompressive cervical spine surgery.

Methods  This randomized controlled trial was conducted over 15 months after obtaining patient consent, approval of the institute ethics committee, and trial registration. We compared preanesthetic fluid loading with Ringer's lactate (20 mL/kg over 30 minutes) with no preloading (2 mL/kg/h maintenance) in 60 consecutive patients undergoing cervical spine surgery. The ANSiscope was used to determine baseline cardiac autonomic function. Noninvasive cardiac output monitor was used to assess changes in heart rate, mean arterial pressure, cardiac index (CI), stroke volume variation (SVV), and total peripheral resistance index during study intervention, anesthetic induction, tracheal intubation, and change in position from supine to prone.

Results  The incidences of postinduction hypotension were 26.7% (8/30) and 86.7% (26/30) and the median doses of mephentermine used were 0 and 6 mg, respectively, in patients with and without fluid preloading (both p  < 0.001). Preloading resulted in improvement in CI, reduction in SVV, and lesser vasopressor use.

Conclusion  Preloading reduced the occurrence of postinduction hypotension and vasopressor use, improved CI, and reduced SVV during the early intraoperative period.

Registration number of Clinical Trial  The trial was registered with Clinical Trial Registry of India (CTRI/2018/07/014970 on 19/07/2018).

End-tidal Carbon Dioxide for Diagnosing Anaphylaxis in Patients with Severe Postinduction Hypotension

BACKGROUND

Perioperative hypersensitivity reactions may be difficult to diagnose during general anesthesia. Postinduction hypotension is the most common sign but is not specific. It was recently suggested that low end-tidal carbon dioxide (ETco2) might be a marker of anaphylaxis (Ring and Messmer grades III to IV immediate hypersensitivity reactions) in hypotensive patients under mechanical ventilation. To test this hypothesis, the authors compared ETco2 in patients with a diagnosis of anaphylaxis and in patients with severe hypotension from any other cause after the induction of anesthesia.

METHODS

This was a retrospective single-center case-control study in which two groups were formed from an anesthesia data warehouse. The anaphylaxis group was formed on the basis of tryptase/histamine assay data and allergy workup data recorded over the period 2010 to 2018. The control (hypotension) group consisted of all patients having experienced severe hypotension (mean arterial pressure less than 50 mmHg for 5 min or longer) with a cause other than anaphylaxis after anesthesia induction in 2017.

RESULTS

The anaphylaxis and hypotension groups comprised 49 patients (grade III: n = 38; grade IV: n = 11) and 555 patients, respectively. The minimum ETco2 value was significantly lower in the anaphylaxis group (median [interquartile range]: 17 [12 to 23] mmHg) than in the hypotension group (32 [29 to 34] mmHg; P < 0.001). The area under the receiver operating characteristic curve (95% CI) for ETco2 was 0.95 (0.91 to 0.99). The sensitivity and specificity (95% CI) for the optimal cutoff value were 0.92 (0.82 to 0.98) and 0.94 (0.92 to 0.99), respectively. In multivariable analysis, minimum ETco2 was associated with anaphylaxis after adjusting for confounders and competing predictors, including arterial pressure, heart rate, and peak airway pressure (odds ratio [95% CI] for ETco2: 0.51 [0.38 to 0.68]; P < 0.001).

CONCLUSIONS

In case of severe hypotension after anesthesia induction, a low ETco2 contributes to the diagnosis of anaphylaxis, in addition to the classical signs of perioperative immediate hypersensitivity.

EDITOR’S PERSPECTIVE

Observer's Assessment of Alertness/Sedation-based titration reduces propofol consumption and incidence of hypotension during general anesthesia induction: A randomized controlled trial

Administration of a single propofol bolus dose for anesthesia induction causes hypotension. We included 160 patients (74 males and 86 females; mean age, 42.4 ± 10.7 [range: 18-60] years) with the American Society of Anesthesiologists status I-II undergoing elective surgery under general anesthesia. Using simple randomization, the patients were divided into a conventional group (n = 80; received 2 mg/kg propofol at a rate of 250 mg/min) and titrated group (n = 80; received propofol at a rate of 1 mg/kg/min until the Observer's Assessment of Alertness/Sedation scale score reached 1 point). Fentanyl (4 µg/kg) and cisatracurium (0.2 mg/kg) were administered, as appropriate. Systolic blood pressure, diastolic blood pressure, mean blood pressure, and heart rate were recorded at different time points. Propofol consumption, hypotension, and other adverse events were recorded. All the patients were intubated without awareness. Compared with the conventional group, the titrated group showed more stable blood pressure (p < 0.05), as well as a lower decrease in systolic blood pressure, mean blood pressure at 1 and 3 min, and diastolic blood pressure at 1 min after propofol administration (p < 0.01). Moreover, compared with the conventional group, the titrated group showed a lower post-intubation hypotension incidence (9 vs. 19 cases; p = 0.04), as well as lower total propofol dosage and propofol dose per kilogram of body weight (93.57 ± 14.40 mg vs. 116.80 ± 22.37 mg and 1.73 ± 0.27 mg/kg vs. 2.02 ± 0.08 mg/kg, respectively, p < 0.01). Compared with conventional propofol usage, titrated propofol administration can reduce the incidence of hypotension and propofol consumption during anesthesia induction.