Non-invasive ventilation for preoxygenation before general anesthesia: a systematic review and meta-analysis of randomized controlled trials

Preoxygenation With and Without Positive End-Expiratory Pressure in Lung-Healthy Volunteers: A Randomized Clinical Trial

Importance

Optimal preoxygenation is critical in emergency medicine to prevent desaturation during airway management, especially in high-risk populations. Identifying the most effective preoxygenation device across diverse patient groups remains a clinical priority.

Objective

To compare the efficacy of 3 preoxygenation devices-nonrebreather mask (NRM), bag-valve mask (BVM), and BVM with positive end-expiratory pressure (BVM plus PEEP)-in lung-healthy volunteers.

Design, Setting, and Participants

This crossover randomized clinical trial was conducted from May 26 to 31, 2024, at Eurac Research, Bolzano, Italy. Volunteer participants included lung-healthy adults with normal weight (NM), adults with overweight or obesity (OW-OB), and children aged 6 to 12 years.

Exposures

Preoxygenation using each device (NRM, BVM, BVM plus PEEP) with 15 L/min of oxygen for a duration of 3 minutes in a randomized order.

Main Outcomes and Measures

The primary outcome was expiratory oxygen concentration (Feo2) at the end of preoxygenation. Secondary outcomes included ventilation in dependent lung regions assessed using electrical impedance tomography, noninvasive continuous monitoring of oxygenation status (oxygenation reserve index [ORI]) at the end of preoxygenation, and the time taken for ORI to return to baseline values.

Results

The study included 53 participants, 39 male (74%) and 14 female (26%), of whom 16 were adults with NW (mean [SD] age, 36 [11] years), 18 were adults with OW-OB (mean [SD] age, 45 [11] years), and 19 were children (mean [SD] age, 8 [3] years). Mean (SD) Feo2 at the end of preoxygenation was higher with BVM and BVM plus PEEP compared with NRM in adults with NW (72.1% [5.9%] and 75.6% [4.3%], respectively, vs 52.5% [6.1%]; P < .001), adults with OW-OB (65.8% [10.4%] and 73.0% [6.4%], respectively, vs 51.9% [6.1%]; P < .001), and children (64.6% [13.4%] and 67.5% [10.2%], respectively, vs 38.5% [7.5%]; P < .001). Ventilation in dependent lung regions was higher with BVM plus PEEP than NRM in adults with NW (BVM plus PEEP, 51.9 [9.3] vs NRM, 47.0 [5.7]; P = .03) and children (BVM plus PEEP, 53.0 [7.3] vs NRM, 47.7 [7.0]; P = .002). ORI at the end of preoxygenation was higher with BVM plus PEEP than with NRM in adults with OW-OB (BVM plus PEEP, 0.79 [0.13] vs NRM, 0.73 [0.13]; P < .001). Additionally, the mean (SE) time for ORI to return to baseline was longer with BVM plus PEEP compared with NRM in both adults with OW-OB (BVM plus PEEP, 196 [74] seconds vs NRM, 158 [53] seconds; P = .01) and children (BVM plus PEEP, 115 [59] seconds vs NRM, 62 [36] seconds; P < .001).

Conclusions and Relevance

In this crossover randomized clinical trial, preoxygenation with PEEP was more effective than preoxygenation without PEEP, resulting in higher Feo2 values and improved ventilation in dependent lung regions. These findings suggest that BVM plus PEEP should be prioritized for preoxygenation in emergency settings.

Trial Registration

ClinicalTrials.gov Identifier: NCT06370689.

Incidence and predisposing factors associated with peri-intubation cardiac arrest: A systematic review and meta-analysis

OBJECTIVES

Various studies have delved into its incidence and risk factors, but a comprehensive meta-analysis exploring this life-threatening complication during emergent endotracheal intubation has been lacking. This study quantitatively assesses the global incidence and associated risk factors of peri-intubation cardiac arrest (PICA).

METHODS

We conducted a systematic literature search on PubMed, Embase, Web of Science, and Cochrane Library from inception to October 28, 2024. Two independent authors searched, reviewed, and evaluated selected studies. Any peer-reviewed published studies reporting the incidence of PICA among adults (≥18 years) outside of the operating theater were included. Studies reporting incidence within heterogeneous populations or from overlapping groups were excluded. The primary outcome focused on determining the global incidence of PICA, while the secondary outcome addressed associated risk factors. A random-effects model was used to aggregate overall incidence rates. Subgroup analysis and meta-regression were conducted to examine PICA incidence in different locations and with the study's sample size. The publication bias was assessed via Egger's test and visualization of the funnel plot. The risk of bias was evaluated using the Joanna Briggs Institute Critical Appraisal Checklist.

RESULTS

Fifteen articles met the inclusion criteria for the meta-analysis. PICA incidence varied from 0.5% to 23.3%. The estimated pooled incidence was 2.7% (95% confidence interval [CI]: 1.9-3.6) across PICA in the emergency department (ED) (2.5%, 95% CI: 1.4-3.7) and outside of the ED (2.9%, 95% CI: 2.2-3.6). Egger's test yielded P = 0.009, indicating potential publication bias due to small-study effects, as suggested by the funnel plot. Meta-regression analysis revealed higher incidence in studies with smaller populations. Notably, preintubation hypotension, hypoxemia, and body mass index were found to be the most associated risk factors for PICA. Additionally, there was significant variability in PICA definitions, ranging from immediate to occurrences within 60 min after intubation.

CONCLUSION

PICA occurrences during emergent endotracheal intubation reached up to 3%, showing a similar rate both within and outside the ED. While limitations such as heterogeneity and potential bias exist, these findings underscore the imperative for prospective research. Prospective studies are warranted to further delineate this critical aspect of emergent intubation.

Preoxygenation strategies for intubation of patients who are critically ill: a systematic review and network meta-analysis of randomised trials

BACKGROUND

Preoxygenation is a crucial preparatory step for intubation. Several strategies for preoxygenation exist, including facemask oxygen, high-flow nasal cannula (HFNC), and non-invasive positive pressure ventilation (NIPPV). However, the comparative efficacy of these strategies remains largely uncertain. We aimed to compare the efficacy and safety of HFNC, NIPPV, and facemask oxygen for preoxygenation of patients who are critically ill requiring tracheal intubation.

METHODS

In this systematic review and network meta-analysis, we searched Embase, MEDLINE, Web of Science, Scopus, and Cochrane Central Register of Controlled Trials for randomised clinical trials published from database inception until Oct 31, 2024, with no language restrictions. We included randomised controlled trials that compared HFNC versus NIPPV, HFNC versus facemask oxygen, or NIPPV versus facemask oxygen in adult patients (age ≥18 years) who were critically ill requiring intubation in the intensive care or emergency department setting. We had no additional eligibility criteria for our network meta-analysis. We used Covidence software to screen eligible trials. Two reviewers independently screened trials for titles and abstracts, and then subsequently screened full-text reports. Discrepancies were resolved by discussion or a third party adjudicator. Summary-level data were extracted manually using a structured data collection form. Outcomes of interest were hypoxaemia during intubation, successful intubation on the first attempt, serious adverse events, and all-cause mortality. We performed a frequentist random-effects network meta-analysis. We assessed the risk of bias using the modified Cochrane tool (RoB 2.0) and the certainty of evidence using the GRADE approach. The protocol is registered on the Open Science Framework.

FINDINGS

We initially identified 6900 records, of which 48 were assessed via full-text screening, and 15 eligible studies with 3420 patients were included in our systematic review and network meta-analysis. Findings suggested that use of NIPPV for preoxygenation probably reduces the incidence of hypoxaemia during intubation versus HFNC (relative risk 0·73 [95% CI 0·55-0·98]; p=0·032; moderate certainty) and reduces the incidence of hypoxaemia versus facemask oxygen (0·51 [0·39-0·65]; p<0·0001; high certainty). HFNC for preoxygenation reduces the incidence of hypoxaemia during intubation versus facemask oxygen (0·69 [0·54-0·88]; p=0·0064; high certainty). None of the preoxygenation strategies affected the incidence of successful intubation on the first attempt (all low certainty). None of the preoxygenation strategies appeared to affect all-cause mortality (very low-to-moderate certainty). NIPPV probably reduces the risk of serious adverse events versus facemask oxygen (0·30 [0·12-0·77]; p=0·011; moderate certainty) and might reduce the risk of serious adverse events versus HFNC (0·32 [0·11-0·91]; p=0·035; low certainty). HFNC might not reduce the risk of serious adverse events versus facemask oxygen (0·95 [0·60-1·51]; p=0·83; low certainty).

INTERPRETATION

Preoxygenation with NIPPV or HFNC rather than facemask oxygen might prevent hypoxaemia during tracheal intubation of adults who are critically ill. Compared with HFNC, NIPPV probably decreases the incidence of hypoxaemia during intubation. Our findings will inform updated international guidelines on preoxygenation.

FUNDING

None.

Non-Invasive Ventilation as a Pre-Oxygenation Strategy During In-Flight Rapid Sequence Intubation: A Case Report

Noninvasive ventilation has been used as a pre-oxygenation strategy for rapid sequence intubation in the emergency department and the intensive care unit, yet, limited research has examined its use in the transport setting. These case reports discuss the use of noninvasive ventilation via a Hamilton T1 ventilator (Hamilton Medical) during transport by an air medical crew for pre-oxygenation before intubation in two cases. In both cases, a noninvasive, bilevel-positive airway pressure mode with a backup rate was used to achieve adequate airway pressures while allowing for a two-handed seal by one emergency medical services clinician as the other prepared the equipment and medications. This method of pre-oxygenation in a space and resource-limited setting was associated with first-pass success without hypoxia in both cases. This adds another method of pre-oxygenation to facilitate safe intubation in similar settings.

Pressure support ventilation improves ventilation during inhalational induction of anesthesia in children: A pilot study

STUDY OBJECTIVE

To evaluate the impact of positive end-expiratory pressure (PEEP) with or without pressure support ventilation (PSV) on the lung volume and the ventilation distribution during inhalational induction of anesthesia in children.

DESIGN

Prospective observational clinical pilot-study.

SETTING

University Children's Hospital of Lyon, France.

PATIENTS

Children without significant comorbidity (ASA 1 or 2) undergoing planned or unplanned surgery with inhalational induction of anesthesia.

INTERVENTION

After the beginning of Guedel's stage 3 of anesthesia, several settings were applied for 60 s in the following systematic order: spontaneous breathing when applying a facemask (SB-Mask), then PEEP 4 cmH2O, PSV 4 cmH2O above PEEP 4 cmH2O, and PSV 4 to 7 cmH2O above PEEP 4 cmH2O, at the anesthesiologist's discretion.

MEASUREMENTS

Children were monitored using Electrical Impedance Tomography (EIT; Pulmovista 500, Dräger, France). Tidal volume (TV), dorsal fraction of the ventilation, and end-expiratory lung impedance (EELI) were assessed with the ventilator and EIT.

MAIN RESULTS

Twenty-two patients were included (20 analyzed), their median [IQR] age was 21 [14-36] months. TV did not significantly differ between the settings. The increase in EELI was greater with PSV (+0.60 [0.48-0.91] arbitrary units) than with PEEP 4 cmH2O alone (+0.39 [0.20-0.06] arbitrary units, p = 0.005), and did not change with increased level of PSV (+0.66 [0.40-1.22] arbitrary units). The dorsal fraction of lung ventilation decreased using PSV, from 56 % [45-63] with SB-mask to 53 % [43-56] with PSV 4cmH2O (p = 0.002) and 47 % [40-55] with PSV 7cmH2O (p = 0.001).

CONCLUSION

The ventilator settings used during inhalational induction of anesthesia in children have an impact on lung ventilation. PSV during inhalational induction of anesthesia in children may restore the end-expiratory lung volume independently from the increase in TV.

Clinical application and progress in preoxygenation techniques

INTRODUCTION

Airway management is often a life-saving procedure for patients. However, during airway management, difficult ventilation and difficult intubation are not always predictable. Preoxygenation, a crucial technique to improve oxygen reserves, plays a vital role in preventing hypoxemia during anesthesia induction. Preoxygenation technology and equipment are not monolithic. With the development of preoxygenation equipment and technology, the effect of preoxygenation has been improved, and it can be applied to different clinical settings.

EVIDENCE ACQUISITION

We conducted a literature search (PubMed and Scopus) in October 2023 with a starting date of January 1985, repeated in August 2024, to identify relevant articles. Key search terms included: 'preoxygenation,' 'high-flow nasal oxygenation,' 'non-invasive ventilation,' 'obese patients,' 'pediatric patients,' and 'elderly patients.'

EVIDENCE SYNTHESIS

The abstracts of identified articles were assessed for relevance, along with screening of their references for further relevant publications. A full-text review of 219 articles was undertaken, of which 77 were included in the final review.

CONCLUSIONS

Preoxygenation is really effective, and different preoxygenation equipment and technology can be applied in different clinical settings to improve the oxygen reserve of patients, thereby ensuring patient safety and improving patient outcome.

The effects of anaesthesia on the cardiovascular, respiratory and nervous systems during inhalational anaesthesia: A case report

Our understanding of the effects of anaesthesia is incomplete. Anaesthesia works primarily by causing widespread depression of the central nervous system. This article will consider the anaesthesia provided for a patient undergoing a hysteroscopy, endometrial ablation and biopsy for abnormal uterine bleeding. The relationship between physiology and the effects of anaesthesia is discussed. Several effects of anaesthesia are observed during the case. Relating to the respiratory system, preoxygenation increased end tidal oxygen by 39%, delaying desaturation during apnoea. Propofol had a profound effect on the patient's respiratory rate by inhibiting the ventilatory drive, resulting in apnoea. The cardiovascular system was affected by tracheal intubation. Stimulation of the sympathetic nervous system caused a 96% increase in heart rate. Induction of anaesthesia resulted in hypotension, treated with the administration of ephedrine, causing vasoconstriction. Modified rapid sequence induction required an increased dose of rocuronium, resulting in an increased duration of action at the neuromuscular junction. The prolonging muscle paralysis required sugammadex as a reversal agent. This case demonstrated the effects of anaesthesia on the respiratory, cardiovascular and nervous systems.

Effectiveness of preoxygenation strategies: a systematic review and network meta-analysis

BACKGROUND

Preoxygenation is universally recommended before induction of general anaesthesia to prolong safe apnoea time. The optimal technique for preoxygenation is unclear. We conducted a systematic review to determine the preoxygenation technique associated with the greatest effectiveness in adult patients having general anaesthesia.

METHODS

We searched six databases for randomised controlled trials of patients aged ≥16 yr, receiving general anaesthesia in any setting and comparing different preoxygenation techniques and methods. Our primary effectiveness outcome was safe apnoea time, and secondary outcomes included incidence of arterial oxygen desaturation; lowest SpO2 during airway management; time to end-tidal oxygen concentration of 90%; and [Formula: see text] and [Formula: see text] at the end of preoxygenation. We assessed the quality of evidence according to Grading of Recommendations, Assessment, Development and Evaluation (GRADE) recommendations.

RESULTS

We included 52 studies of 3914 patients. High-flow nasal oxygen with patients in a head-up position was most likely to be associated with a prolonged safe apnoea time when compared with other strategies, with a mean difference (95% credible interval) of 291 (138-456) s and 203 (79-343) s compared with preoxygenation with a facemask in the supine and head-up positions, respectively. Subgroup analysis of studies without apnoeic oxygenation also showed high-flow nasal oxygen in the head-up position as the highest ranked technique, with a statistically significantly delayed mean difference (95% credible interval) safe apnoea time compared with facemask in supine and head-up positions of 222 (63-378) s and 139 (15-262) s, respectively. High-flow nasal oxygen was also the highest ranked technique for increased [Formula: see text] at the end of preoxygenation. However, the incidence of arterial desaturation was less likely to occur when a facemask with pressure support was used compared with other techniques, and [Formula: see text] was most likely to be lowest when preoxygenation took place with patients deep breathing in a supine position.

CONCLUSIONS

Preoxygenation of adults before induction of general anaesthesia was most effective in terms of safe apnoea time when performed with high-flow nasal oxygen with patients in the head-up position in comparison with facemask alone. Also, high-flow nasal oxygen in the head-up position is likely to be the most effective technique to prolong safe apnoea time among those evaluated. Clinicians should consider this technique and patient position in routine practice.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO CRD42022326046.

Noninvasive Ventilation for Preoxygenation during Emergency Intubation

BACKGROUND

Among critically ill adults undergoing tracheal intubation, hypoxemia increases the risk of cardiac arrest and death. The effect of preoxygenation with noninvasive ventilation, as compared with preoxygenation with an oxygen mask, on the incidence of hypoxemia during tracheal intubation is uncertain.

METHODS

In a multicenter, randomized trial conducted at 24 emergency departments and intensive care units in the United States, we randomly assigned critically ill adults (age, ≥18 years) undergoing tracheal intubation to receive preoxygenation with either noninvasive ventilation or an oxygen mask. The primary outcome was hypoxemia during intubation, defined by an oxygen saturation of less than 85% during the interval between induction of anesthesia and 2 minutes after tracheal intubation.

RESULTS

Among the 1301 patients enrolled, hypoxemia occurred in 57 of 624 patients (9.1%) in the noninvasive-ventilation group and in 118 of 637 patients (18.5%) in the oxygen-mask group (difference, -9.4 percentage points; 95% confidence interval [CI], -13.2 to -5.6; P<0.001). Cardiac arrest occurred in 1 patient (0.2%) in the noninvasive-ventilation group and in 7 patients (1.1%) in the oxygen-mask group (difference, -0.9 percentage points; 95% CI, -1.8 to -0.1). Aspiration occurred in 6 patients (0.9%) in the noninvasive-ventilation group and in 9 patients (1.4%) in the oxygen-mask group (difference, -0.4 percentage points; 95% CI, -1.6 to 0.7).

CONCLUSIONS

Among critically ill adults undergoing tracheal intubation, preoxygenation with noninvasive ventilation resulted in a lower incidence of hypoxemia during intubation than preoxygenation with an oxygen mask. (Funded by the U.S. Department of Defense; PREOXI ClinicalTrials.gov number, NCT05267652.).

The comparison of preoxygenation methods before endotracheal intubation: a network meta-analysis of randomized trials

Background

Preoxygenation before endotracheal intubation (ETI) maintains asphyxiated oxygenation and reduces the risk of hypoxia-induced adverse events. Previous studies have compared various preoxygenation methods. However, network meta-analyses (NMAs) of the combined comparison of preoxygenation methods is still lacking.

Methods

We searched for studies published in PubMed, Embase, Web of Science, Scopus, and the Cochrane Library. Review Manager version 5.3 was used to evaluate the risk of bias. The primary outcome of this meta-analysis was low oxygen saturation (SpO2) during ETI. The secondary outcomes included SpO2 <80%, SpO2 <90%, and apnea time during ETI. NMA was performed using R 4.1.2 software gemtc packages in RStudio.

Results

A total of 15 randomized controlled trials were included in this study. Regarding the lowest SpO2, the noninvasive ventilation (NIV) with high-flow nasal cannula (HFNC) group performed better than the other groups. For SpO2 <80%, the NIV group (0.8603467) performed better than the HFNC (0.1373533) and conventional oxygen therapy (COT, 0.0023) groups, according to the surface under the cumulative ranking curve results. For SpO2 <90%, the NIV group (0.60932667) performed better than the HFNC (0.37888667) and COT (0.01178667) groups. With regard to apnea time, the HFNC group was superior to the COT group (mean difference: -50.05; 95% confidence interval: -90.01, -10.09; P = 0.01).

Conclusion

Network analysis revealed that NIV for preoxygenation achieved higher SpO2 levels than HFNC and COT and offered a more significant advantage in maintaining patient oxygenation during ETI. Patients experienced a longer apnea time after HFNC preoxygenation. The combination of NIV with HFNC proved to be significantly superior to other methods. Given the scarcity of such studies, further research is needed to evaluate its effectiveness.

Systematic review registration

identifier CRD42022346013.

Risk factors for peri-intubation cardiac arrest: A systematic review and meta-analysis

BACKGROUND

Peri-intubation cardiac arrest (PICA) is an uncommon yet serious complication of intubation. Although some associated risk factors have been identified, the results have been inconsistent. The aim of this study was to systematically review the relevant research and examine the associated risk factors of PICA through meta-analysis.

METHODS

Studies examining the risk factors for PICA before 1 Nov. 2022 were identified through searches in MEDLINE (OvidSP) and EMBASE. The reported adjusted or unadjusted odds ratios (ORs) and risk ratios (RRs) were recorded. We calculated pooled ORs and created forest plots using a random-effects model to identify the statistically significant risk factors. We assessed the certainty of evidence for each risk factor.

RESULTS

Eight studies were included in the meta-analysis. Pre-intubation hypotension, with a pooled OR of 4.96 (95% confidence interval [C.I.]: 3.75-6.57), pre-intubation hypoxemia, with a pooled OR of 4.43 (95% C.I.: 1.24-15.81), and two or more intubation attempts, with a pooled OR of 1.88 (95% C.I.: 1.09-3.23) were associated with a significantly higher risk of PICA. The pooled incidence of PICA was 2.1% (95% C.I.: 1.5%-3.0%).

CONCLUSIONS

Pre-intubation hypotension, hypoxemia, and more intubation attempts are significant risk factors for PICA. The findings could help physicians identify patients at risk under the acute setting.

Spanish Society of Anesthesiology, Reanimation and Pain Therapy (SEDAR), Spanish Society of Emergency and Emergency Medicine (SEMES) and Spanish Society of Otolaryngology, Head and Neck Surgery (SEORL-CCC) Guideline for difficult airway management. Part I

The Airway Management section of the Spanish Society of Anesthesiology, Resuscitation, and Pain Therapy (SEDAR), the Spanish Society of Emergency Medicine (SEMES), and the Spanish Society of Otorhinolaryngology and Head and Neck Surgery (SEORL-CCC) present the Guide for the comprehensive management of difficult airway in adult patients. Its principles are focused on the human factors, cognitive processes for decision-making in critical situations, and optimization in the progression of strategies application to preserve adequate alveolar oxygenation in order to enhance safety and the quality of care. The document provides evidence-based recommendations, theoretical-educational tools, and implementation tools, mainly cognitive aids, applicable to airway management in the fields of anesthesiology, critical care, emergencies, and prehospital medicine. For this purpose, an extensive literature search was conducted following PRISMA-R guidelines and was analyzed using the GRADE methodology. Recommendations were formulated according to the GRADE methodology. Recommendations for sections with low-quality evidence were based on expert opinion through consensus reached via a Delphi questionnaire.

Pressure-controlled versus manual facemask ventilation for anaesthetic induction in adults: A randomised controlled non-inferiority trial

BACKGROUND

Pressure-controlled face mask ventilation (PC-FMV) with positive end-expiratory pressure (PEEP) after apnoea following induction of general anaesthesia prolongs safe apnoea time and reduces atelectasis formation. However, depending on the set inspiratory pressure, a delayed confirmation of a patent airway might occur. We hypothesised that by lowering the peak inspiratory pressure (PIP) when using PC-FMV with PEEP, confirmation of a patent airway would not be delayed as studied by the first return of CO2 , compared with manual face mask ventilation (Manual FMV).

METHODS

This was a single-centre, randomised controlled non-inferiority trial. Seventy adult patients scheduled for elective day-case surgery under general anaesthesia with body mass index between 18.5 and 29.9 kg m-2 , American Society of Anesthesiologists (ASA) classes I-III, and without anticipated difficult FMV, were included. Before the start of pre-oxygenation and induction of general anaesthesia, participants were randomly allocated to receive ventilation with either PC-FMV with PEEP, at a PIP of 11 and a PEEP of 6 cmH2 O or Manual FMV, with the adjustable pressure-limiting valve set at 11 cmH2 O. The primary outcome variable was the number of ventilatory attempts needed until confirmation of a patent airway, defined as the return of at least 1.3 kPa CO2 .

RESULTS

The return of ≥1.3 kPa CO2 on the capnography curve was observed after mean ± SD, 3.6 ± 4.2 and 2.5 ± 1.9 ventilatory attempts/breaths with PC-FMV with PEEP and Manual FMV, respectively. The difference in means (1.1 ventilatory attempts/breaths) had a 99% CI of -1.0 to 3.1, within the accepted upper margin of four breaths for non-inferiority.

CONCLUSION

Following induction of general anaesthesia, PC-FMV with PEEP was used without delaying a patent airway as confirmed with capnography, if moderate pressures were used.

Nasal continuous positive pressure versus simple face mask oxygenation for adult obese and obstructive sleep apnea patients undergoing colonoscopy under propofol-based general anesthesia without tracheal intubation: A randomized controlled trial

STUDY OBJECTIVE

To determine if a nasal positive airway pressure (nasal CPAP) mask would decrease the number of hypoxemic events in obese and obstructive sleep apnea patients undergoing colonoscopy.

DESIGN

Single-center prospective randomized controlled trial.

SETTING

Tertiary academic center.

PATIENTS

We enrolled 109 patients with diagnosis of obesity and/or obstructive sleep apnea scheduled to undergo colonoscopy under propofol general anesthesia without planned tracheal intubation.

INTERVENTION

Patients were randomly allocated (1:1 ratio) to receive supplementary oxygen at a flow of 10 L/min, either through a nasal CPAP or a simple facemask.

MEASUREMENTS

The primary endpoint was the difference in the mean percentage of time spent with oxygen saturation below 90% between the two groups. Secondary outcomes included the need for airway maneuvers/interventions, average SpO2 during the case, duration and severity of oxygen desaturation, incidence and duration of procedural interruptions, and satisfaction and tolerance scores.

MAIN RESULTS

54 were allocated to the simple face mask and 55 to the nasal CPAP mask arms, respectively. A total of 6 patients experienced a hypoxemic event. Among these patients, the difference in the percentage of time spent with oxygen saturation below 90% was not clinically relevant (p = 1.0). However, patients in the nasal CPAP group required less chin lift (20% vs. 42.6%; p = 0.01) and oral cannula insertion (12.7% vs.29.6%; p = 0.03). The percentage of patients with at least one airway maneuver was higher in the simple face mask arm (68.5% vs. 41.8%; p = 0.005). Patient tolerance to device score was lower in the nasal CPAP group (8.85 vs. 9.56; p = 0.003).

CONCLUSIONS

A nasal CPAP did not prevent hypoxemia and should not be used routinely for colonoscopy in obese or OSA patients if a simple face mask is an alternative therapy. However, potential advantages of its use include fewer airway maneuvers or interventions, which may be desirable in certain clinical settings.

TRIAL REGISTRATION

Clinicaltrials.gov, identifier: NCT05175573.

Day-surgery adult patients with obesity and obstructive sleep apnea: Current controversies and concerns

Obesity and obstructive sleep apnea are considered independent risk factors that can adversely affect perioperative outcomes. A combination of these two conditions in the ambulatory surgery patient can pose significant challenges for the anesthesiologist. Nevertheless, these patients should not routinely be denied access to ambulatory surgery. Instead, patients should be appropriately optimized. Anesthesiologists and surgeons must work together to implement fast-track anesthetic and surgical techniques that will ensure successful ambulatory outcomes.