Clinical predictors of apnoea-hypopnoea during propofol sedation in patients undergoing spinal anaesthesia*

Apnea during moderate to deep sedation using continuous infusion of remimazolam compared to propofol and dexmedetomidine: A retrospective observational study

Remimazolam's rapid onset and offset make it an innovative sedative for use during regional anesthesia. However, its respiratory safety profile is not well understood. We compared the continuous infusion of remimazolam with commonly used sedatives, propofol and dexmedetomidine, after regional anesthesia. In this retrospective study, the incidence of apnea (>10 seconds) was assessed in patients who underwent orthopedic surgery under regional anesthesia and received moderate to deep sedation using continuous infusion of remimazolam (group R: 0.1 mg/kg in 2 minutes followed by 0.5 mg/kg/hr). The incidence was compared with that of propofol (group P: 2-3 μg/mL target-controlled infusion) and dexmedetomidine (group D: 1 μg/kg in 10 minutes followed by 0.4-1 μg/kg/hr). Propensity score weighted multivariable logistic regression model was utilized to determine the effects of the sedative agents on the incidence of apnea. A total of 634 (191, 278, and 165 in group R, P, and D) cases were included in the final analysis. The incidence of apnea was 63.9%, 67.3%, and 48.5% in group R, P, and D, respectively. The adjusted odds ratios for apnea were 2.33 (95% CI, 1.50 to 3.61) and 2.50 (95% CI, 1.63 to 3.85) in group R and P, compared to group D. The incidence of apnea in patients receiving moderate to deep sedation using continuous infusion of remimazolam with dosage suggested in the current study was over 60%. Therefore, careful titration and respiratory monitoring is warranted.

Incidence and Nature of Respiratory Events in Patients Undergoing Bronchoscopy Under Conscious Sedation

BACKGROUND

During diagnostic bronchoscopies, conscious sedation improves patient tolerance, but it can contribute to hypercapnia and hypoxia by various mechanisms including depression of ventilatory drive. This prospective study was undertaken to determine the frequency of respiratory events and associated oxygen desaturations during bronchoscopy with conscious sedation.

PATIENTS AND METHODS

The Nox-T3 monitoring system was placed before starting the bronchoscopy and remained in place for 30 minutes following the procedure. The primary endpoint was the occurrence of obstructive and central apneic events during bronchoscopy under conscious sedation.

RESULTS

Obstructive events (apnea and hypopnea) occurred in 100% of patients (n=31), and central apneas occurred in 58% of patients (n=18) during the procedure with a median of 9 and 2 events per patient, respectively. During recovery, a significant proportion of patients had detectable obstructive (86%) and central (36%) events. Higher body mass index was associated with oxygen desaturation to <90% and with the need for escalation of care. Furthermore, a conscious sedation regimen that included propofol was significantly associated with central apneic events.

CONCLUSION

Respiratory events are common during and immediately postprocedure after conscious sedation for bronchoscopy. Most events are obstructive, and the use of propofol predisposes to central apneas during the procedure. Both types of events are associated with a higher body mass index. Oxygen desaturation to <90% triggers escalation of care. A further prospective study will be required to determine the clinical significance of these apneic events and whether alleviating these events will improve the safety and outcomes of bronchoscopic procedures performed under conscious sedation.

Supraglottic Airway Use for Transfemoral-Transcatheter Aortic Valve Replacement

OBJECTIVE

Examine outcome differences in patients managed either with a supraglottic airway or an endotracheal tube for general anesthesia during transcatheter aortic valve replacement. The authors hypothesized that patients managed with a supraglottic airway would have shorter post-anesthesia care unit and hospital stays and receive fewer opioids, norepinephrine equivalents, and neuromuscular blocking agents, without an increase in 30-day major adverse cardiovascular events.

DESIGN

Retrospective chart review with 1:2 supraglottic airway-to-endotracheal tube patient propensity score matching.

SETTING

Single, urban, tertiary care, academic medical center.

PARTICIPANTS

Patients undergoing transfemoral- transcatheter aortic valve replacement between 2017 and 2019.

INTERVENTIONS

Supraglottic or endotracheal tube airway management during general anesthesia.

MEASUREMENTS AND MAIN RESULTS

Thirty-one supraglottic airway patients were propensity score matched with 62 endotracheal tube patients. There was no significant difference for postanesthesia care unit (p = 0.58) or hospital (p = 0.16) lengths of stay. Supraglottic airway patients received significantly fewer neuromuscular blockers (p < 0.0001) and trended toward fewer opioids (p = 0.05), but received a similar number of norepinephrine equivalents (p = 0.76). The major adverse cardiovascular event odds ratio between groups was 1.39 (p = 0.51). The time under general anesthesia (p = 0.02) and total time in the operating room (p = 0.04) were significantly shorter for supraglottic airway patients.

CONCLUSIONS

Supraglottic airway management in transcatheter aortic valve replacement was feasible without an increase in major adverse cardiovascular outcomes compared with endotracheal tube management during general anesthesia. Supraglottic airway patients trended toward receiving fewer opioids and received significantly fewer neuromuscular blockers while also having significantly shorter time under general anesthesia and total time in the operating room.

Effects of continuous positive airway pressure in patients at high risk of obstructive sleep apnea during propofol sedation after spinal anesthesia

In patients with obstructive sleep apnea, short-term use of a continuous positive airway pressure mask improves oxygenation, decreases the apnea-hypopnea index, and reduces hemodynamic instability. In this study, we investigated the effects of use of a continuous positive airway pressure mask in patients at high risk of obstructive sleep apnea during propofol sedation after spinal anesthesia. Forty patients who underwent propofol sedation after spinal anesthesia for transurethral bladder or prostate resection with a STOP-Bang score of 3 or more were enrolled in this study. Patients were randomly divided into two groups: a simple oxygen mask group (n = 20) and a continuous positive airway pressure mask group (n = 20). After spinal anesthesia, propofol was injected at a target concentration of 1.3 mcg/ml via a target concentration control injector. ApneaLink™ was applied to all patients. Patients in the simple oxygen mask group were administered oxygen at a rate of 6 L/min through a simple facial mask. Patients in the CPAP mask group were connected to a pressurizer, and oxygen (6 L/min, 5-15 cm H₂O) was administered. Blood pressure, heart rate, respiratory rate, and oxygen saturation were recorded preoperatively, after spinal anesthesia, and every 5 min after the injection of propofol to observe hemodynamic changes. Apnea-hypopnea index was estimated using ApneaLink™. There were no significant differences in hemodynamic changes between the two groups. Apnea-hypopnea index was significantly reduced in the continuous positive airway pressure mask group compared to the simple facial mask group. Application of a continuous positive airway pressure mask in a patient at high risk of obstructive sleep apnea can lower the incidence of obstructive sleep apnea during sedation without a significant effect on hemodynamic stability.

An update on the various practical applications of the STOP-Bang questionnaire in anesthesia, surgery, and perioperative medicine

Purpose of review

The present review aims to provide an update on the various practical applications of the STOP-Bang questionnaire in anesthesia, surgery, and perioperative medicine.

Recent findings

The STOP-Bang questionnaire was originally validated as a screening tool to identify surgical patients who are at high-risk of obstructive sleep apnea (OSA). A recent meta-analysis confirmed that STOP-Bang is validated for use in the sleep clinic, surgical, and general population. Patients with a STOP-Bang score of 0--2 can be classified as low-risk for moderate-to-severe OSA. Those with a score of 5--8 can be classified as high-risk for moderate-to-severe OSA. In patients with a score of 3 or 4, a specific combination of a STOP score at least 2 + BMI more than 35 kg/m² or STOP score at least 2 + male or STOP score at least 2 + neck circumference more than 40 cm indicates higher risk for moderate-to-severe OSA. Further, patients with a STOP-Bang score at least 3 can be classified as high risk for moderate-to-severe OSA if the serum HCO₃^- at least 28 mmol/l. STOP-Bang can be used as a novel tool for perioperative risk stratification because it easily identifies patients who are at increased risk of perioperative complications.

Summary

STOP-Bang at least 3 was recommended previously to identify the suspected or undiagnosed OSA. To reduce the false positive cases and to improve its specificity, a stepwise stratification is recommended to identify the patients at high risk of moderate-to-severe OSA. Because of its practical application, STOP-Bang is a useful screening tool for patients with suspected or undiagnosed OSA.

Society of Anesthesia and Sleep Medicine Guidelines on Preoperative Screening and Assessment of Adult Patients With Obstructive Sleep Apnea

Supplemental Digital Content is available in the text.

The purpose of the Society of Anesthesia and Sleep Medicine guideline on preoperative screening and assessment of adult patients with obstructive sleep apnea (OSA) is to present recommendations based on the available clinical evidence on the topic where possible. As very few well-performed randomized studies in this field of perioperative care are available, most of the recommendations were developed by experts in the field through consensus processes involving utilization of evidence grading to indicate the level of evidence upon which recommendations were based. This guideline may not be appropriate for all clinical situations and all patients. The decision whether to follow these recommendations must be made by a responsible physician on an individual basis. Protocols should be developed by individual institutions taking into account the patients’ conditions, extent of interventions and available resources. This practice guideline is not intended to define standards of care or represent absolute requirements for patient care. The adherence to these guidelines cannot in any way guarantee successful outcomes and is rather meant to help individuals and institutions formulate plans to better deal with the challenges posed by perioperative patients with OSA. These recommendations reflect the current state of knowledge and its interpretation by a group of experts in the field at the time of publication. While these guidelines will be periodically updated, new information that becomes available between updates should be taken into account. Deviations in practice from guidelines may be justifiable and such deviations should not be interpreted as a basis for claims of negligence.

Validation of the STOP-Bang Questionnaire as a Screening Tool for Obstructive Sleep Apnea among Different Populations: A Systematic Review and Meta-Analysis

Background

Diagnosing obstructive sleep apnea (OSA) is clinically relevant because untreated OSA has been associated with increased morbidity and mortality. The STOP-Bang questionnaire is a validated screening tool for OSA. We conducted a systematic review and meta-analysis to determine the effectiveness of STOP-Bang for screening patients suspected of having OSA and to predict its accuracy in determining the severity of OSA in the different populations.

Methods

A search of the literature databases was performed. Inclusion criteria were: 1) Studies that used STOP-Bang questionnaire as a screening tool for OSA in adult subjects (>18 years); 2) The accuracy of the STOP-Bang questionnaire was validated by polysomnography—the gold standard for diagnosing OSA; 3) OSA was clearly defined as apnea/hypopnea index (AHI) or respiratory disturbance index (RDI) ≥ 5; 4) Publications in the English language. The quality of the studies were explicitly described and coded according to the Cochrane Methods group on the screening and diagnostic tests.

Results

Seventeen studies including 9,206 patients met criteria for the systematic review. In the sleep clinic population, the sensitivity was 90%, 94% and 96% to detect any OSA (AHI ≥ 5), moderate-to-severe OSA (AHI ≥15), and severe OSA (AHI ≥30) respectively. The corresponding NPV was 46%, 75% and 90%. A similar trend was found in the surgical population. In the sleep clinic population, the probability of severe OSA with a STOP-Bang score of 3 was 25%. With a stepwise increase of the STOP-Bang score to 4, 5, 6 and 7/8, the probability rose proportionally to 35%, 45%, 55% and 75%, respectively. In the surgical population, the probability of severe OSA with a STOP-Bang score of 3 was 15%. With a stepwise increase of the STOP-Bang score to 4, 5, 6 and 7/8, the probability increased to 25%, 35%, 45% and 65%, respectively.

Conclusion

This meta-analysis confirms the high performance of the STOP-Bang questionnaire in the sleep clinic and surgical population for screening of OSA. The higher the STOP-Bang score, the greater is the probability of moderate-to-severe OSA.

Effect of sedative-hypnotics, anesthetics and analgesics on sleep architecture in obstructive sleep apnea

The perioperative care of obstructive sleep apnea (OSA) patients is currently receiving much attention due to an increased risk for complications. It is established that postoperative changes in sleep architecture occur and this may have pathophysiological implications for OSA patients. Upper airway muscle activity decreases during rapid eye movement sleep (REMS). Severe OSA patients exhibit exaggerated chemoreceptor-driven ventilation during non-rapid eye movement sleep (NREMS), which leads to central and obstructive apnea. This article critically reviewed the literature relevant to preoperative screening for OSA, prevalence of OSA in surgical populations and changes in postoperative sleep architecture relevant to OSA patients. In particular, we addressed three questions in regard to the effects of sedative-hypnotics, anesthetics and analgesics on sleep architecture, the underlying mechanisms and the relevance to OSA. Indeed, these classes of drugs alter sleep architecture, which likely significantly contributes to abnormal postoperative sleep architecture, exacerbation of OSA and postoperative complications.