Obstetric Anaesthetists' Association and Difficult Airway Society guidelines for the management of difficult and failed tracheal intubation in obstetrics

Rate of difficult intubation during caesarean delivery: A single centre before/after standardised airway management implementation study

BACKGROUND

The use of general anaesthesia (GA) for caesarean delivery (CD) introduces the risk of both difficult and failed intubation. Various strategies may be utilised to reduce this risk; however, not all are supported by evidence. We analysed the rate of difficult intubation following implementation of three recommendations specific to airway management in CD.

METHODS

This was a retrospective single-center study of CD cases performed under GA at a tertiary care center between January 2013 and December 2022. Cases with GA induced after delivery or with incomplete airway management records were not included in the analysis. We compared outcomes for cases before (2013-2018) versus after (2019-2022) implementation of three specific recommendations: (1) video laryngoscopy (VL) for the first intubation attempt; (2) the presence of a second anesthetist; (3) use of endotracheal tube size 6.5 mm. The primary outcome was difficult intubation, defined as a composite variable (> 1 intubation attempt, use of a rescue device, SpO2 < 90%). We conducted univariable and adjusted analyses of plausible variables associated with difficult intubation, including age, body mass index, predicted difficult airway, and each of three recommendations.

RESULTS

We identified 1462 cases, 922 before and 540 after implementation. The frequency of difficult intubation was similar with 239 (25.9%) before versus 135 (25.0%) after implementation (p = 0.71; 95% CI -0.03 to 0.05). The recommendations were not associated with a decreased likelihood of difficult intubation in the univariable and adjusted models. Adoption of all three recommendations was significantly more frequent in the post-implementation period.

CONCLUSION

Implementation of standardised airway management recommendations had no significant impact on difficult intubation rate, though adoption of all three recommendations was not universal.

Development of the obstetric unanticipated difficult video-laryngoscopy algorithm through a quality improvement randomized open-label in situ simulation study

BACKGROUND

Video-laryngoscopy is increasingly used during general anesthesia for emergency cesarean deliveries. Given the heightened risk of difficult tracheal intubation in obstetrics, addressing challenges in airway management is crucial. In this simulation study, we hypothesized that using a flexible bronchoscope would lead to securing the airway faster than the Eschmann introducer when either device is used in addition to video-laryngoscopy.

METHODS

Twenty-eight anesthesia trainees (n=14/group) were randomized to use either one of the rescue devices and video-recorded in a simulated scenario of emergency cesarean delivery. The primary outcome was the time difference in establishing intubation; secondary outcomes were the differences in incidence of hypoxemia, need for bag and mask ventilation, and failed intubation between the two rescue devices.

RESULTS

Mean (±SD) time to intubation using flexible bronchoscopy was shorter compared to using an Eschmann introducer (24 ± 10 vs 86 ± 35 s; P<0.0001; difference in mean 62 seconds, 95% CI 42 to 82 seconds). In the fiberoptic bronchoscopy group, there were no episodes of hypoxemia or need for bag and mask ventilation; in contrast both such events occurred frequently in the Eschmann introducer group (71%, 10/14); P=0.0002). All flexible bronchoscopy-aided intubations were established on the first attempt. The incidence of failed intubation was similar in both groups.

CONCLUSIONS

Our data from simulated emergency tracheal intubation suggest that flexible bronchoscopy combined with video-laryngoscopy results in faster intubation time than using an Eschmann introducer combined with video-laryngoscopy.

Pre-oxygenation using high flow humidified nasal oxygen or face mask oxygen in pregnant people - a prospective randomised controlled crossover non-inferiority study (The HINOP2 study)

BACKGROUND

Airway guidelines recommend pre-oxygenation of obstetric patients to an end tidal oxygen concentration (etO2) ≥90%. High flow nasal oxygen (HFNO) achieves this in 60% of pregnant people. However face mask (FM) pre-oxygenation also may not achieve this target in all patients. In this study we determined whether HFNO pre-oxygenation is non-inferior to FM pre-oxygenation.

METHODS

This randomised controlled crossover non-inferiority trial was conducted on healthy participants of gestational age ≥37 weeks in a simulated environment. Participants underwent pre-oxygenation for three minutes with HFNO and FM oxygen in randomised order. HFNO was delivered at a maximal flow of 70 l.min-1 and FM oxygen at 10 l.min-1. The primary outcome was etO2 on first expired breath after pre-oxygenation. Non-inferiority was defined as a mean difference in first etO2 between groups of ≤5%.

RESULTS

Seventy participants were randomised with 62 analysed. Age (mean (SD)), gestation (median (IQR)), and body mass index (median (IQR)), were 34.7 (4.6) years, 39 (38.4, 39.4) weeks, 29 (26.6, 32.4) kg.m-2 respectively. First etO2 after HFNO pre-oxygenation was greater than after FM pre-oxygenation (HFNO pre-oxygenation mean (SD) 90.2 (3.9)% versus FM pre-oxygenation 88.7 (3.0)%; mean difference = 1.45%, 95% CI 0.19 to 2.72%; p = 0.025. Forty-four (71%) participants achieved ≥90% first etO2 concentration after HFNO pre-oxygenation versus 27 (44%) after FM pre-oxygenation (p = 0.002).

CONCLUSIONS

In this cohort of pregnant people at term in a simulated environment, pre-oxygenation with HFNO was not inferior to FM pre-oxygenation. FM pre-oxygenation did not achieve pre-oxygenation targets in over 50% of participants.

Gastric emptying in pregnancy and its clinical implications: a narrative review

Delayed gastric emptying increases the risk of pulmonary aspiration during anaesthesia for Caesarean delivery. Our aim in conducting this narrative review was to consider the effect of pregnancy on gastric emptying. The indices of gastric emptying after liquids, solids, or both and when fasted in the various trimesters of pregnancy, at the time of Caesarean delivery, in labour, and the postpartum period were assessed. We considered 32 observational studies, one nonrandomised controlled study, and 22 randomised controlled trials. The evidence indicates that, compared with the nonpregnant state, gastric emptying is decreased in the first but not the second and third trimesters. Before elective Caesarean delivery, carbohydrate drink or tea with milk leads to no difference in gastric cross-sectional area at 2 h relative to fasting or water. Following a standard fast for elective Caesarean delivery, patients may still have high-risk gastric contents. Compared with the nonpregnant state and third trimester, gastric emptying is delayed in labour, although the choice of analgesia has modifying effects. Systemic opioids delay gastric emptying. Epidural analgesia increases gastric emptying, but not back to baseline. Intrathecal analgesia delays gastric emptying relative to epidural analgesia. Women in labour who have eaten solids in the last 8 h still have high-risk gastric contents present in the stomach. The evidence with respect to the postpartum period is conflicting. In conclusion, inconsistencies in the literature reflect the unpredictability of gastric emptying in pregnancy and underline the potential value of gastric ultrasound in women who are pregnant.

Airway management for patients with tracheal stenosis and severe scar contracture of the face and neck via bronchoscopy: a case report

Both anaesthesiologists and surgeons experience challenges in managing airway stenosis and scar contracture in the face and neck. Herein, we report the case of a 38-year-old woman (BMI 23.1 kg/m2, third-degree burns covering 40% of her body, an American Society of Anaesthesiologists physical status III) with an unusual case of airway constriction. This patient had a predictable difficult airway (mouth opening of 2 cm, bilateral nostril scar hyperplasia, Mallampatti score III, scarring of the head and neck, and severe tracheal stenosis). Tracheal stenosis measuring 5.5 mm in width as observed 8 cm below the glottis, and the bronchoscope could not pass through it. After two failed attempts at laryngeal mask insertion, we decided to instead insert a custom-made tracheal tube under the guidance of a fiberoptic bronchoscope. The operation was successful, and the patient was transferred to the intensive care unit (ICU).

The role of supraglottic airway devices for caesarean section under general anaesthesia. A scoping literature review with a proposed algorithm for the appropriate use of supraglottic airway devices for caesarean sections

This review aims to assess the published evidence on airway management with a supraglottic airway device (SGA) for general anaesthesia in patients requiring a caesarean section. Physiological changes during pregnancy can make airway management in parturients challenging. At the same time, pregnant patients are at risk of pulmonary aspiration due to hormonal and mechanical alterations. The standard airway management for parturients undergoing caesarean section is rapid sequence induction followed by tracheal intubation. Evidence exists that using second-generation SGA devices is well tolerated and effective in selected patients. In this review, we provide an overview of the existing evidence and provide an algorithm to make an evidence-based clinical decision on the use of SGA devices. An online literature search was performed in Medline, Embase, PubMed, Emcare, Cochrane Library and CINAHL. The search terms used were 'supraglottic airway', 'supraglottic airway device', 'supraglottic airway management', 'supraglottic tube', 'i-gel', laryngeal mask', 'laryngeal mask airway', 'LMA', 'SGA', 'Proseal', 'Supreme', 'obstetric surgery', 'obstetric operation', 'general anaesthesia', 'caesarean' or 'caesarean section', 'abdominal delivery'. Full-text articles in English, Dutch and French were included. Case reports and studies in which the surgery was not a caesarean section were excluded. The initial search yielded 815 results. Following screening, deduplication and removal of publications that were unrelated to the topic or did not fit the inclusion criteria, 13 manuscripts were included in our analysis. A total of 7722 patients were described in the articles included. In the majority of manuscripts, second-generation SGA devices were used. There were seven cases of failed insertion and a need for conversion to tracheal intubation; first-generation SGA devices were used in these cases. There were no cases of pulmonary aspiration, and only one case of gastric regurgitation was described. Growing evidence suggests that the use of second-generation SGA devices might be well tolerated as the primary method for securing the airway for caesarean sections requiring general anaesthesia, in selected patients with a low risk for aspiration and difficult intubation.

Anesthesia Management in Antenatal Care for Women With Chronic Kidney Disease: A Comprehensive Review

Chronic kidney disease (CKD) presents significant challenges in the management of pregnant women due to its impact on renal function and cardiovascular stability. This review examines the crucial role of anesthesia management in antenatal care for women with CKD, focusing on the complexities introduced by renal dysfunction and the implications for maternal and fetal health outcomes. The review discusses the physiological changes in CKD during pregnancy, highlighting the increased risks of hypertension, proteinuria, and adverse fetal outcomes. Anesthesia considerations, including the choice of anesthesia techniques (general anesthesia, regional anesthesia), perioperative monitoring, and management of fluid and electrolyte balance, are analyzed in the context of CKD-specific challenges. Clinical outcomes and current evidence regarding anesthesia efficacy and safety in CKD patients are reviewed, emphasizing the need for tailored anesthesia protocols to ensure optimal maternal comfort and fetal safety. The review concludes by identifying research gaps and proposing future directions to enhance anesthesia practices and improve outcomes for pregnant women with CKD undergoing surgical interventions or labor management.

Non-inferiority randomized controlled trial comparing CricOid pressure and para-laryngeal pressure in parturients undergoing cesarean delivery: NiCOP trial

BACKGROUND

Cricoid pressure has been surrounded with controversies regarding its effectiveness. Application of ultrasound-guided para-laryngeal (PL) force has been shown to occlude the esophagus effectively compared with cricoid pressure (CP) in awake patients. We hypothesized that there would be no meaningful difference in the change in antero-posterior esophageal diameter from with application of cricoid or para-laryngeal pressure in parturients undergoing cesarean delivery under general anesthesia.

METHODS

In this prospective, randomized, non-inferiority trial, 40 parturients scheduled for elective cesarean delivery under general anesthesia were randomized to receive rapid sequence induction with either cricoid pressure (n = 20) or para-laryngeal pressure (n = 20). The antero-posterior diameter of the esophagus, measured by sonography, was the primary outcome. Visualization of the esophagus, its position in relation to the glottic aperture, esophageal occlusion, percentage of glottic opening (POGO), time to intubation, first pass success rate, overall success rate and adverse events like desaturation or bronchospasm were secondary outcomes.

RESULTS

The mean change in anterior-posterior diameter in the CP group was 0.17 ±0.1 cm vs. 0.28 ±0.1 cm in the PL group. The mean difference (CP-para-laryngeal pressure) between the groups was -0.11 (95% CI -0.17 to -0.1) cm. As the upper limit of the 95% CI was lower than the prespecified non-inferiority margin (δ = -0.2), non-inferiority was established (P <0.001]. There was no significant difference in the POGO score (P = 0.818), time to intubation (P =0.55), or intubation attempts (P = 0.99).

CONCLUSIONS

Para-laryngeal pressure was non-inferior to CP in occluding the esophagus in parturients undergoing cesarean delivery under general anesthesia and furthermore, no significant deterioration in intubation parameters was seen.

Eliminating residual neuromuscular blockade: a literature review

Background and Objective

Although millions of patients receive neuromuscular blocking agents (NMBAs) each year as part of an anesthetic, residual neuromuscular blockade (NMB) remains a too-frequent occurrence and its adverse consequences continue to negatively impact patient outcomes. The goal of this manuscript is to provide clinicians with the information they need to decrease the incidence of residual NMB.

Methods

Published literature was reviewed and incorporated into the narrative as appropriate. Search terms for articles included nondepolarizing NMBAs, residual NMB, monitoring depth of NMB, qualitative monitoring, quantitative monitoring, reversal agents, sugammadex, and anticholinesterases.

Key Content and Findings

This review will define what is currently considered adequate recovery of neuromuscular function, discuss and compare the different modalities to determine the depth of NMB, discuss the currently available NMBAs-including their durations of action and dosing, describe the incidence and complications associated with residual NMB, and discuss reversal of nondepolarizing NMB with neostigmine or sugammadex. Nondepolarizing NMBAs are commonly used as part of a general anesthetic. Understanding the pharmacology of the neuromuscular blocking and reversal agent, in combination with quantitative monitoring of depth of NMB is essential to avoid residual paralysis.

Conclusions

Quantitative monitoring and dosing of either neostigmine or sugammadex based on the results of monitoring is essential to eliminate residual NMB associated with the use of nondepolarizing NMBAs.

National variation in guidance for the management of pregnant women presenting with major trauma

INTRODUCTION

The initial assessment of pregnant women presenting with significant injuries is more complicated than that of non-pregnant women because of physiological and anatomical changes, and the presence of the fetus. The aim of this study was to determine whether guidelines for the early management of severely injured pregnant women exist, which aspects of assessment/management they cover and to what extent there is national consistency.

METHODS

A freedom of information request was submitted to 125 acute National Health Service trusts in England and six in Wales. The trusts were asked to confirm whether they have a guideline for the management of major trauma in pregnant women presenting to the emergency department and what the guidelines were.

RESULTS

In total, 96.2% of trusts responded, of which 19% have a specific guideline and 7.9% have a generic guideline for assessing pregnant women in the emergency department, irrespective of injury severity. Of the responding trusts, 19.8% have a protocol that specifies when an obstetric trauma call should be put out by the emergency department and when a pregnant woman should be transferred to a major trauma centre for definitive management. Our results found that 69.8% routinely call obstetrics or gynaecology to the trauma call compared with 36.5% calling paediatrics.

CONCLUSIONS

The heterogeneity evident across trusts necessitates the establishment of national guidelines for the assessment of pregnant women with major trauma to standardise communication and delivery of care.

Anesthetic dilemmas in an achondroplastic patient undergoing elective cesarean section

Achondroplasia is a genetic condition characterized by skeletal dysplasia that results in characteristic craniofacial and spinal abnormalities. It is the most common form of short-limbed skeletal dysplasia. Additionally, a pregnant patient who is morbidly obese warrants specific anatomical and physiological considerations, such as a difficult airway with potential hypoxia, full stomach precautions, and a reduced functional residual capacity. Achondroplasia increases the risks of maternal and fetal complications. Although neuraxial techniques are generally preferred for cesarean sections, there is no consensus among patients with achondroplasia. We aimed to discuss the anesthetic challenges in an achondroplastic patient and report our regional anesthesia approach for an elective cesarean section.

Airway management and pulmonary aspiration during surgical interventions in pregnant women in the 2nd/3rd trimester and immediate postpartum - a retrospective study in a tertiary care university hospital

BACKGROUND

Pregnancy is associated with an increased risk of pulmonary aspiration during general anaesthesia, but the incidence of this complication is not well defined.

METHODS

We performed a retrospective database review in a tertiary care university hospital to determine the incidence of pulmonary aspiration in pregnant patients undergoing endotracheal intubation, with and without Rapid Sequence Induction (RSI), as well as face-mask ventilation and supraglottic airway devices. We included Patients in the 2nd or 3rd trimester of pregnancy and immediate postpartum undergoing surgical procedures. The primary endpoint was the occurrence of pulmonary aspiration.

RESULTS

Data from 2,390 patients undergoing general anaesthesia for cerclage of cervix uteri, manual removal of retained placenta, repair of obstetric laceration, or postpartum bleeding were retrospectively evaluated. A supraglottic airway device or face-mask ventilation was used in 1,425/2,390 (60%) of patients, while 638/2,390 (27%) were intubated. RSI was used in 522/638 (82%) of patients undergoing tracheal intubation, or 522/2,390 (22%) of the entire cohort. In-depth review of the charts, including 54 patients who had been initially classified as "possible pulmonary aspiration" by anaesthetists, revealed that this adverse event did not occur in the cohort.

CONCLUSIONS

In conclusion, in this obstetric surgery patient population at risk for pulmonary aspiration, supraglottic airway devices were used in approximately 60% of cases. Yet, no aspiration event was detected with either a supraglottic airway or endotracheal intubation.

Anesthetic Practices for Lower Segment Cesarean Section in the Sultanate of Oman: A National Survey

Background Over the years, obstetric anesthesia has evolved into a comprehensive sub-specialty. Several countries have their guidelines and recommendations for obstetric anesthesia. This survey aimed to describe the current obstetric anesthesia practices in the Sultanate of Oman by performing a questionnaire-based survey. Methods The Ministry of Health-Centre approved the survey for Studies and Research, Sultanate of Oman (MOH-CSR/25057). A Google Form with 25 questions (seven general questions and 18 specific questions) was initially shared in a WhatsApp group of members of the Oman Society of Anaesthesia and Critical Care (OSACC). Anesthesiologists who were not members were contacted directly and responses were recorded. Results Responses were accepted until midnight on December 31, 2023. The number of responses received was 66. Variations in practices like less compliance to Enhanced Recovery After Surgery (ERAS) pathways, use of oxytocin, and choice of intrathecal opioids were observed. Labor analgesia was not practiced by 30.3% of respondents. The majority of respondents did not follow international recommendations regarding the use of the uterotonic drug oxytocin. Conclusion A lot of heterogeneity in the practice of obstetric anesthesia in the Sultanate of Oman was observed. The limitations included the relatively low number of responses and many aspects that were missed in the survey. The findings of this survey will help in establishing a national task force for obstetric anesthesia, which will guide the members of the task force to develop practice guidelines based on international recommendations and the latest evidence.

The impact of general anesthesia on the outcomes of preterm infants with gestational age less than 32 weeks delivered via cesarean section

Background

Recent advancements in China's perinatal and neonatal intensive care have significantly reduced neonatal mortality, yet preterm births before 32 weeks remain the primary cause of neonatal fatalities and contribute to long-term disabilities. The prognosis of very preterm infants (VPIs) is significantly affected by factors including the intrauterine environment, delivery method and neonatal intensive care. Cesarean section which often used for preterm births has implications that are not fully understood, particularly concerning the type of anesthesia used. This study examines the impact of general anesthesia (GA) during cesarean delivery on VPI outcomes, aiming to identify strategies for mitigating GA-associated risks.

Methods

This cohort study analyzed 1,029 VPIs born via cesarean section under 32 weeks' gestation at our single-center from 1 January 2018, to 31 December 2022. Detailed medical records, encompassing perioperative information, maternal data and neonatal outcomes were meticulously examined. The primary aim of this investigation was to compare maternal characteristics and neonatal outcomes between VPIs delivered under GA and neuraxial anesthesia (NA). A significance level of p < 0.05 was established.

Results

Of the 1,029 VPIs analyzed, 87.95% (n = 905) were delivered via NA and 12.05% (n = 124) via GA. Mothers with hypertensive pregnancy diseases and emergency operations were more inclined to choose GA. VPIs delivered under GA showed a lower Apgar score at one and 5 minutes (p < 0.01), increased need for tracheal intubation resuscitation (32.2% vs. 12.2%, p < 0.01) and a greater incidence of severe neurological injury (SNI) (14.5% vs. 5%, p < 0.01). Multivariable analysis revealed GA was significantly associated with lower Apgar scores at one (OR 6.321, 95% CI 3.729-10.714; p < 0.01) and 5 minutes (OR 4.535, 95% CI 2.975-6.913; p < 0.01), higher risk of tracheal intubation resuscitation (OR = 3.133, 95% CI = 1.939-5.061; p < 0.01) and SNI (OR = 3.019, 95% CI = 1.615-5.643; p < 0.01). Furthermore, for VPIs delivered under GA, a prolonged interval from skin incision to fetus delivery was associated with a lower 5-min Apgar score (p < 0.01).

Conclusion

This study revealed the significant impact of GA on adverse outcomes among VPIs. In cases when GA is required, proactive measures should be instituted for the care of VPIs such as expediting the interval from skin incision to fetal delivery.

Rapid sequence induction of anesthesia: works in progress and steps forward with focus to oxygenation and monitoring techniques

The description of the main scientifically consolidated innovations in recent years on Rapid Sequence Induction have been the subject of this narrative review. Data sources were PubMed, EMBASE, Web of Science, the Cochrane Central Register of Controlled Trials, and ClinicaTrials.gov, searched up to March 21st, 2023; rapid sequence induction and anesthesia were used as key word for the research. In recent years at least three significant innovations which have improved the procedure: firstly the possibility of using drugs which rapidly reverse the action of the myorelaxants and which have made it possible to give up the use of succinylcholine, replaced by rocuronium; secondly, the possibility of using much more effective pre-oxygenation methods than in the past, also through apneic oxygenation techniques which allow longer apnea time, and finally new monitoring systems much more effective than pulse oximetry in identifying and predicting periprocedural hypoxemia and indicating the need for ventilation in patients at risk of hypoxemia and preventing it. The description of three main scientifically consolidated innovations in recent years, in pharmacology, oxygen method of administration and monitoring, have been the subject of this narrative review.

Narrative Review and Consensus Recommendations for the Use of Transnasal Humidified Rapid-Insufflation Ventilatory Exchange in Modified Electroconvulsive Therapy

Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) is a safe, effective, and novel technique that is currently being used in electroconvulsive therapy (ECT). This study aimed to summarize the clinical practices of THRIVE use in ECT to aid physicians and institutions in implementing the best practice guidelines for ECT. Thus, we reviewed the current literature and presented our consensus on the application of THRIVE in ECT in daily clinical practice. This consensus provides information regarding THRIVE use in ECT, including its safety, effectiveness, procedures, precautions, special case management, and application in special populations. Moreover, it guides the standardized use of THRIVE in ECT.

Novice learners' perspectives on obstetric airway crisis decision-making training using virtual reality simulation

BACKGROUND

Current training on managing an obstetric difficult airway crisis is likely inadequate, as real-life opportunities to practice are rare. Frequent simulation training sessions could be helpful but are resource intensive. Virtual reality (VR) simulation training may be a potential tool to complement existing simulation curricula.

METHODS

In this pilot qualitative study, a VR simulation scenario of an obstetric airway crisis was designed to test the decision-making of novice learners rotating through obstetric anesthesia training. Individual interviews were conducted pre-VR to assess learning needs and post-VR to assess perspectives on utilizing the VR teaching tool. The interviews were transcribed and thematically analyzed.

RESULTS

Twenty-one residents were recruited and participated in the study. Analysis of pre-VR interviews identified three major themes, including gaps in the current curriculum, lack of confidence in managing obstetric difficult airway crises, and recognition that simulation is resource intensive. Post-VR interview themes revealed that VR could be helpful in learning decision-making under stress. Suggested improvements included better video and audio quality, and adding haptic feedback and potential multiplayer features in the future.

CONCLUSION

We identified the advantages of VR simulation and its potential as an intervention to address gaps in our curriculum. Areas of improvement were identified for more effective future implementation.

Management of the Difficult Airway: An Appraisal of Clinical Practice Guidelines

OBJECTIVE

Management of the difficult airway can be a challenging process, which necessitates actionable recommendations from well-established guidelines. Herein, clinical practice guideline (CPG) quality is evaluated using the Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument.

STUDY DESIGN

A systematic literature search was performed using Scopus, EMBASE, and MEDLINE via PubMed.

SETTING

Literature database.

METHODS

Data were abstracted from relevant guidelines and appraised by 4 expert reviewers in the 6 domains of quality defined by AGREE II. Intraclass correlation coefficients (ICC) were calculated across domains to quantify interrater reliability.

RESULTS

Twelve guidelines met the inclusion criteria. With a mean quality score of 83.1%, the highest quality guideline was authored by the American Society of Anesthesiologists (ASA). Low-quality content was observed in CPGs authored by the Japanese Society of Anesthesiologists (JSA) and the Chinese Collaboration Group for Emergency Airway Management (CCGEAM). Overall, deficits were most pronounced in domains describing the involvement of stakeholders, developmental rigor, and editorial independence. These findings were consistent among the panel of independent reviewers, with high ICC inter-rater reliability scores of 58.0% to 70.0% for the referenced domains.

CONCLUSION

By providing a comprehensive appraisal of guidelines, this report may serve as a reference for clinicians seeking to understand and improve upon the developmental quality of difficult airway management resources. According to AGREE II criteria for the quality of the guideline creation process, the 2022 ASA guideline outperforms its predecessors.

From Brobdingnag to Lilliput: Gulliver's travels in airway management guidelines

Neonatal airway management comes with exclusive anatomical, physiological, and environmental complexities, and probably higher incidences of accidents and complications. No dedicated airway management guidelines were available until the recently published first joint guideline released by a task force supported by the European Society of Anaesthesiology and Intensive Care and the British Journal of Anaesthesia and focused on airway management in children under 1 yr of age. The guideline offers a series of recommendations based on meticulous methodology including multiple Delphi rounds to complement the sparse and scarce available evidence. Getting back from Brobdingnag, the land of giants with many guidelines available, this guideline represents a foundational cornerstone in the land of Lilliput.

Validating Parallel-Forms Tests for Assessing Anesthesia Resident Knowledge

We created a serious game to teach first year anesthesiology (CA-1) residents to perform general anesthesia for cesarean delivery. We aimed to investigate resident knowledge gains after playing the game and having received one of 2 modalities of debriefing. We report on the development and validation of scores from parallel test forms for criterion-referenced interpretations of resident knowledge. The test forms were intended for use as pre- and posttests for the experiment. Validation of instruments measuring the study's primary outcome was considered essential for adding rigor to the planned experiment, to be able to trust the study's results. Parallel, multiple-choice test forms development steps included: (1) assessment purpose and population specification; (2) content domain specification and writing/selection of items; (3) content validation by experts of paired items by topic and cognitive level; and (4) empirical validation of scores from the parallel test forms using Classical Test Theory (CTT) techniques. Field testing involved online administration of 52 shuffled items from both test forms to 24 CA-1's, 21 second-year anesthesiology (CA-2) residents, 2 fellows, 1 attending anesthesiologist, and 1 of unknown rank at 3 US institutions. Items from each form yielded near-normal score distributions, with similar medians, ranges, and standard deviations. Evaluations of CTT item difficulty (item p values) and discrimination (D) indices indicated that most items met assumptions of criterion-referenced test design, separating experienced from novice residents. Experienced residents performed better on overall domain scores than novices (P < .05). Kuder-Richardson Formula 20 (KR-20) reliability estimates of both test forms were above the acceptability cut of .70, and parallel forms reliability estimate was high at .86, indicating results were consistent with theoretical expectations. Total scores of parallel test forms demonstrated item-level validity, strong internal consistency and parallel forms reliability, suggesting sufficient robustness for knowledge outcomes assessments of CA-1 residents.

Placenta accreta spectrum care infrastructure: an evidence-based review of needed resources supporting placenta accreta spectrum care

The incidence of placenta accreta spectrum, the deeply adherent placenta with associated increased risk of maternal morbidity and mortality, has seen a significant rise in recent years. Therefore, there has been a rise in clinical and research focus on this complex diagnosis. There is international consensus that a multidisciplinary coordinated approach optimizes outcomes. The composition of the team will vary from center to center; however, central themes of complex surgical experts, specialists in prenatal diagnosis, critical care specialists, neonatology specialists, obstetrics anesthesiology specialists, blood bank specialists, and dedicated mental health experts are universal throughout. Regionalization of care is a growing trend for complex medical needs, but the location of care alone is just a starting point. The goal of this article is to provide an evidence-based framework for the crucial infrastructure needed to address the unique antepartum, delivery, and postpartum needs of the patient with placenta accreta spectrum. Rather than a clinical checklist, we describe the personnel, clinical unit characteristics, and breadth of contributing clinical roles that make up a team. Screening protocols, diagnostic imaging, surgical and potential need for critical care, and trauma-informed interaction are the basis for comprehensive care. The vision from the author group is that this publication provides a semblance of infrastructure standardization as a means to ensure proper preparation and readiness.

Anesthetic challenges of pregnant obesity women

Obesity causes significant morbidity and increases the mortality risk for both mother and fetus. With an increasing projected prevalence, it is vital that the obstetric anesthetist is equipped with the knowledge and tools to manage these women. A multi-disciplinary team approach and early planning is required. Neuraxial analgesia for labor helps to negate the need for general anesthesia, which is associated with increased risk in this subset of women. Catheter techniques for neuraxial anesthesia allow for titration, manipulation, and prolongation of the anesthetic block to reduce the risk of conversion to general anesthesia.

Videolaryngoscopy as a primary intubation modality in obstetrics: A narrative review of current evidence

Pregnancy-related physiologic and anatomic changes affect oxygenation and airway management, and it is widely believed that airway difficulty may be more common in obstetric patients as a result. In addition, most obstetric intubations are performed under emergency conditions, and preoperative airway assessment poorly predicts airway management outcomes. These considerations necessitate special protocols for airway care in the obstetric population, and the evolution of the videolaryngoscope represents one of the most important milestones in recent decades. However, recommendations for the use of videolaryngoscopy in obstetrics remain unclear. A considerable body of evidence affirms that videolaryngoscopy improves laryngeal visualisation, increases first-attempt and overall intubation success rates, shortens intubation time, and facilitates team communication and education. In contrast, a significant number of studies have also reported conflicting results regarding comparative clinical outcomes and have highlighted other limitations regarding the adoption of videolaryngoscopy in routine obstetric care. Nevertheless, considering the peculiarities of obstetric intubation, the Macintosh-style videolaryngoscope can be suggested as the primary intubation device as it offers the benefits of both videolaryngoscopy and direct laryngoscopy. However, more rigorous evidence is needed to clarify the current blind spots and controversies regarding the role of videolaryngoscopy in obstetrics.

Analysis of anaesthesia incidents during caesarean section reported to webAIRS between 2009 and 2022

Anaesthesia for caesarean section occurs commonly and places specific demands on anaesthetists. We analysed 469 narratives concerning anaesthesia for caesarean section, entered by Australian and New Zealand anaesthetists into the webAIRS incident reporting system between 2009 and 2022. As expected, compared with the remaining 8978 database entries, the 469 incidents were more likely to be emergency cases (relative risk (RR) 1.95), more likely to occur between 18:00 and 22:00 hours (RR 1.81) and between 22:00 and 07:59 hours (RR 4.40) and more likely to be undertaken using neuraxial anaesthesia (RR 9.18). Most incidents involved more than one event. The most commonly reported incidents included intraoperative neuraxial anaesthesia complications (180, 38%), medication errors or issues (136, 29%), equipment issues (49, 10%), obstetric haemorrhage (38, 8%), maternal cardiac arrests (28, 6%), endotracheal tube issues (28, 6%) and neonatal resuscitation (24, 5%). Inadequate neuraxial block, reported in 95 incidents, was the most common intraoperative neuraxial complication. Allergic reactions, reported in 30 incidents, were the most common medication issue, followed by 17 associated with oxytocin and 16 syringe swaps. Thirty-eight reports included significant maternal haemorrhage, with eight of those incidents including maternal cardiac arrest. There was one maternal death and eight incidents with neonatal deaths reported, affecting nine neonates. Problems with intraoperative neuraxial anaesthesia were the most commonly reported events. Implementation of specific strategies are encouraged to enhance preparation for conversion to general anaesthesia and to mitigate medication errors, particularly those relating to oxytocic use and neuraxial anaesthesia medications.

Simple steps towards improving safety in obstetric airway management: A quality improvement project

BACKGROUND

Guidelines from the Obstetric Anaesthetists' Association and Difficult Airway Society state that 'a videolaryngoscope should be immediately available for all obstetric general anaesthetics'.

OBJECTIVE

To report the incidence of videolaryngoscopy use, and other airway management safety interventions, in an obstetric population before and after various quality improvement interventions.

DESIGN

Prospective data collection was undertaken over 18 months, divided into three separate 6-month periods: June to November 2019; March to August 2021; January to June 2022. These periods relate to evaluation of specific quality improvement interventions.

SETTING

The project was carried out in a large tertiary referral obstetric unit.

PATIENTS

We identified 401 pregnant women (> 20 weeks' gestation) and postnatal women (up to 48 h post delivery) undergoing an obstetric surgical procedure under general anaesthesia.

INTERVENTIONS

To standardise practice, an intubation checklist was introduced in December 2020 and multidisciplinary staff training in August 2021.

MAIN OUTCOME MEASURES

Primary outcome measures were use of a Macintosh-style videolaryngoscope and tracheal intubation success. Secondary outcome measures were use of an intubation checklist; low flow nasal oxygen; and ramped patient positioning.

RESULTS

Data from 334 tracheal intubations (83.3% of cases) were recorded. Videolaryngoscope use increased from 60% in 2019, to 88% in 2021, to 94% in 2022. Tracheal intubation was successful in all patients, with 94% first pass success overall and only 0.9% requiring three attempts. Use of secondary outcome measures also increased: low flow nasal oxygen from 48% in 2019 to 90% in 2022; ramped positioning from 95% in 2021 to 97% in 2022; and checklist use from 63% in 2021 to 92% in 2022.

CONCLUSIONS

We describe the successful adoption of simple safety measures introduced into routine practice. These comprised videolaryngoscopy, ramped positioning and low flow nasal oxygen. Their introduction was supported by the implementation of an intubation checklist and multidisciplinary team training.

High-Flow Oxygen Therapy in the Perioperative Setting and Procedural Sedation: A Review of Current Evidence

High-flow oxygen therapy (HFOT) is a respiratory support system, through which high flows of humidified and heated gas are delivered to hypoxemic patients. Several mechanisms explain how HFOT improves arterial blood gases and enhances patients' comfort. Some mechanisms are well understood, but others are still unclear and under investigation. HFOT is an interesting oxygen-delivery modality in perioperative medicine that has many clinical applications in the intensive care unit (ICU) and the operating room (OR). The purpose of this article was to review the literature for a comprehensive understanding of HFOT in the perioperative period, as well as its uses in procedural sedation. This review will focus on the HFOT definition, its physiological benefits, and their mechanisms, its clinical uses in anesthesia, and when it is contraindicated.

Otolaryngology and the Pregnant Patient

Importance

Pregnancy may result in physiologic and pathologic changes in the head and neck. Otolaryngologists may need to intervene medically or surgically with pregnant patients. Careful consideration of risks to both the gravid patient and the developing fetus is vital.

Observations

Patients may present with otolaryngologic complaints exacerbated by or simply occurring during their pregnancy. Symptoms of hearing loss, vertigo, rhinitis or rhinosinusitis, epistaxis, obstructive sleep apnea, sialorrhea, voice changes, reflux, subglottic stenosis, and benign and malignant tumors of the head and neck may prompt evaluation. While conservative measures are often best, there are medications that are safe for use during pregnancy. When required, surgery for the gravid patient requires a multidisciplinary approach.

Conclusions and Relevance

Otolaryngologic manifestations in pregnant patients may be managed safely with conservative treatment, medication, and surgery when necessary. Treatment should include consideration of both the pregnant patient and the developing fetus.

Anesthetic Management for Cesarean Delivery in a Patient With a Difficult Airway and Risks for Postpartum Hemorrhage: A Case Report

Neuraxial anesthesia is the preferred anesthesia technique for cesarean delivery, however, conversion to general anesthesia may be required for a variety of clinical scenarios, including massive post-partum hemorrhage. Obstetric patients are known to have otherwise more difficult airways and emergent situations can increase the likelihood of failed intubation with potentially disastrous consequences. We describe a novel anesthesia technique for cesarean delivery using neuraxial anesthesia as the primary anesthetic technique and electively securing the airway for a patient with multiple risk factors for post-partum hemorrhage and features concerning difficult intubation.

Global obstetric anaesthesia: bridging the gap in maternal health care inequities through partnership in education

Maternal mortality rates are unacceptably high globally. Low- and middle-income countries (LMICs) face challenges of an inadequate anaesthesia workforce, under-resourced healthcare systems and sub-optimal access to labour and delivery care, all of which negatively impact maternal and neonatal outcomes. In order to effect the changes in surgical-obstetric-anaesthesia workforce numbers advocated by the Lancet Commission on Global Surgery to support the UN sustainable development goals, mass training and upskilling of both physician and non-physician anaesthetists is imperative. The implementation of outreach programmes and partnerships across organisations and countries has already been shown to improve the provision of safe care to mothers and their babies, and these efforts should be continued. Short subspecialty courses and simulation training are two cornerstones of modern obstetric anaesthesia training in poorly resourced environments. This review discusses the challenges to accessing quality maternal healthcare in LMICs and the use of education, outreach, partnership and research to protect the most vulnerable women from coming to harm in the peripartum period.

Supreme laryngeal mask airway for cesarean section under general anesthesia: a 10-year retrospective cohort study

Background

Previous research showed the use of supraglottic airways in obstetric anesthesia. The relevant evidence of laryngeal mask airway (LMA) on maternal and neonatal outcomes is still limited. We aimed to assess the maternal and neonatal outcomes when the LMA Supreme was used for cesarean section under general anesthesia.

Methods

We included all patients who underwent general anesthesia for cesarean section between January 2010 and December 2019. Propensity score matching was used to reduce potential bias from non-random selection of airway intervention. The primary outcome was adverse maternal and neonatal outcomes defined as maternal regurgitation, aspiration, hypoxemia, and low neonatal Apgar scores. Secondary outcomes included patient admission to the intensive care unit, neonate required tracheal intubation, external cardiac massage, and admission to the neonatal intensive care unit.

Results

A total of 723 patients were included in the analysis; of whom, 221 received Supreme laryngeal mask airway (LMA group) and 502 were intubated with an endotracheal tube (ETT group). After propensity score matching, 189 patients remained in each group. No episode of regurgitation and aspiration occurred in both groups. There was no difference in the rates of Apgar score below 7 at 1 min (14.3% LMA group vs. 15.3% ETT group, OR 0.931, 95% CI 0.574 to 1.510, P = 0.772) and 5 min (3.7% vs. 4.2%, OR 0.875, 95% CI 0.324 to 2.365, P = 0.792). No difference was observed in the secondary outcomes between the two groups.

Conclusion

The LMA Supreme was not associated with higher adverse maternal and neonatal outcomes when compared to an endotracheal tube for cesarean section under general anesthesia. It might be considered an alternative to tracheal intubation in obstetric practice.

A Systematic Review and Meta-Analysis of Randomized Controlled Trials on Supine vs. Nonsupine Endotracheal Intubation

Background

This systematic review and meta-analysis of randomized controlled trials (RCTs) was performed to compare the safety and efficacy of supine vs. nonsupine positions during intubation.

Methods

Based on the literature from inception to October 2020, 13 studies with nonemergent intubation in supine and nonsupine positions were chosen using PRISMA and MOOSE protocols. Pooled estimates were calculated using random-effects models with 95% confidence interval (CI). The primary outcome was a successful intubation, attempt, and duration of intubation. The secondary outcome was adverse events (trauma and hypoxia). Bias was evaluated qualitatively, by visual analysis, and quantitatively through the Egger test.

Results

The final analysis included 13 clinical trials with 1,916 patients. The pooled success rates in the supine vs. lateral positions were 99.21% and 98.82%. The supine vs. semierect positions were 99.21% and 98.82%. The 1st attempt success rate in the supine vs. lateral position was 85.35% and 88.56% compared to 91.38% and 90.76% for the supine vs. semierect position. The rate of total adverse events in the supine position was 3.73% vs. 6.74% in the lateral position, and the rate of total adverse events in the supine position was 0.44% vs. 0.93% in semierect position. Low to substantial heterogeneity was noted in our analysis. Discussion. There is no significant difference between total successful intubations and success from 1st intubation attempt between supine and nonsupine positions. However, there are slightly higher rates of adverse events in nonsupine position. Addition of more recent studies on supine vs. nonsupine intubations would improve this study. Given these findings, it is important to develop more studies regarding different intubation positions and techniques with the aim of improving efficacy and decreasing adverse outcomes. Other. This review is not registered in a public database. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

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.

The role of supraglottic airway devices in obstetric anaesthesia

PURPOSE OF REVIEW

To discuss the role of supraglottic airway devices as rescue and primary airway devices in pregnant patients.

RECENT FINDINGS

General anaesthesia in pregnant patients is associated with increased incidence of difficult and failed intubation, especially when performed for caesarean deliveries. The Difficult Airway Society and the Obstetric Anaesthetists' Association guidelines for the management of failed intubation recommend the use of second-generation supraglottic airway devices as a rescue airway strategy when failed intubation occurs. This practice is now widely accepted and embedded in routine teaching and clinical practice. On the other hand, there is little but growing evidence describing the use of supraglottic airway devices as the primary airway device and an alternative to endotracheal intubation for patients undergoing elective and emergency caesarean deliveries under general anaesthesia. Most of the published research supporting this practice was done on carefully selected patients who were nonobese and who did not have gastroesophageal reflux or anticipated difficult airway. Despite demonstrating high insertion success rates and low complication rates, these studies were underpowered and have thus far, failed to provide robust data on the true risk of aspiration in this setting.

SUMMARY

Based on current scientific data, the evidence for the safe use of supraglottic airway devices as primary airway devices during general anaesthesia for caesarean deliveries is not compelling. However, their use as rescue airway devices remains a well established strategy supported by international guidelines.

Trauma in Pregnancy

Trauma is the leading cause of nonobstetric maternal death. Pregnant patients have a similar spectrum of traumatic injuries with a noted increase in interpersonal violence. A structured approach to trauma evaluation and management is recommended with several guidelines expanding on ATLS principles; however, evidence is limited. Optimal management requires understanding of physiologic changes in pregnancy, a team-based approach, and preparation for interventions that may including neonatal resuscitation. The principles of trauma management are the same in pregnancy with a systematic approach and initial maternal focused resuscitation..

The Management of Pregnant Trauma Patients: A Narrative Review

Trauma is the leading nonobstetric cause of maternal death and affects 1 in 12 pregnancies in the United States. Adhering to the fundamentals of the advanced trauma life support (ATLS) framework is the most important component of care in this patient population. Understanding the significant physiologic changes of pregnancy, especially with regard to the respiratory, cardiovascular, and hematologic systems, will aid in airway, breathing, and circulation components of resuscitation. In addition to trauma resuscitation, pregnant patients should undergo left uterine displacement, insertion of 2 large bore intravenous lines placed above the level of the diaphragm, careful airway management factoring in physiologic changes of pregnancy, and resuscitation with a balanced ratio of blood products. Early notification of obstetric providers, initiation of secondary assessment for obstetric complications, and fetal assessment should be undertaken as soon as possible but without interference to maternal trauma assessment and management. In general, viable fetuses are monitored by continuous fetal heart rate for at least 4 hours or more if abnormalities are detected. Moreover, fetal distress may be an early sign of maternal deterioration. When indicated, imaging studies should not be limited out of fear for fetal radiation exposure. Resuscitative hysterotomy should be considered in patients approaching 22 to 24 weeks of gestation, who arrive in cardiac arrest or present with profound hemodynamic instability due to hypovolemic shock.

AIRWAY MANAGEMENT GUIDELINES IN OBSTETRICS

Anatomic and physiologic changes during pregnancy make it more difficult to establish a safe airway in pregnant women in case of the need for surgery under general anesthesia than in the non-obstetric population. The inability to ventilate and oxygenate is one of the most common causes of morbidity and mortality associated with general anesthesia for cesarean section. The aim of this paper is to present and analyze modern guidelines and algorithms for the management of difficult airway in obstetrics as an important segment of anesthesiology practice. Modern difficult airway management guidelines for pregnant women describe the procedure of difficult facemask ventilation, difficult airway management by using supraglottic devices, difficult endotracheal intubation, and emergency cricothyrotomy or tracheotomy in a situation where oxygenation and ventilation are impossible. Algorithms describe the procedures and equipment for each variant of difficult airway and decision-making strategies in situations when neither airway nor adequate oxygenation can be provided. Croatian anesthesiologists in most obstetric departments have appropriate equipment, as well as necessary experience in difficult airway management for pregnant women, and modern algorithms from the most developed countries can be adopted and accommodated to our daily practice, as well as incorporated into the training curricula of residents.

What we need to know and do on sugammadex usage in pregnant and lactating women and those on hormonal contraceptives

Sugammadex is a chemically modified γ-cyclodextrin that is used as a selective reversal agent for steroidal neuromuscular blockade. The use of sugammadex has greatly increased globally; however, little is known about its potential adverse effects in pregnant and lactating women or those using hormonal contraceptives. There are three important theoretical assumptions. Firstly, pregnancy-related physiological changes involve most organs and affect the pharmacokinetic profiles of medications. Considering the physiological changes in pregnant women and the pharmacokinetic properties of sugammadex, alterations in the dosage and safety profiles of sugammadex may occur during pregnancy. Secondly, very large and polarized sugammadex molecules are expected to have limited placental transfer to the fetus and excretion into breast milk. Finally, sugammadex can bind to steroidal neuromuscular blocking agents as well as other substances with similar structures, such as progesterone. As a result of using sugammadex, progesterone levels can be reduced, causing adverse effects such as early pregnancy cessation and failure of hormonal contraceptives. This narrative review aims to demonstrate the correlations between sugammadex and pregnancy, lactation, and reproductive potential based on previously published preclinical and clinical studies. This will bridge the gap between theoretical assumptions and currently unknown clinical facts. Moreover, this review highlights what anesthesia providers should be aware of and what actions to take while administering sugammadex to such patients.

High-Flow Nasal Cannula for Apneic Oxygenation in Obese Patients for Elective Surgery: A Systematic Review and Meta-Analysis

BACKGROUND

Obese patients desaturate rapidly during the apneic period after induction of anesthesia for elective surgery. Administration of oxygen using high-flow nasal cannulae (HFNCs) may prevent desaturation in nonobese patients compared to facemask (FM) preoxygenation. The aim of this meta-analysis was to compare the effectiveness of HFNC to FM preoxygenation techniques in reducing preintubation desaturation in obese patients undergoing elective surgery.

METHODS

This study protocol was registered on PROSPERO (CRD42022309391). Adult studies that compared HFNC and FM preoxygenation in obese patients requiring general anesthesia for elective surgery were included. The primary outcome was desaturation resulting in oxygen saturation of <92% from induction of anesthesia until intubation. Secondary outcomes included the lowest arterial oxygen content before intubation expressed in mm Hg, safe apnea time expressed in seconds, the lowest oxygen saturation before intubation expressed as a percentage, patient-reported discomfort, the need for rescue ventilation, and the incidence of aspiration of gastric contents during intubation. Risk of bias was assessed using the Cochrane Collaboration tool. Certainty was assessed following the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

Six studies including 351 participants were eligible for analysis. There was no difference in odds of oxygen desaturation <92% between HFNC and FM (odds ratio [OR], 0.49; 95% confidence interval [CI], 0.15-1.63; P = .24). The HFNC group had a significantly longer safe apnea time (mean difference [MD], -124.20 with 95% CI, -200.47 to -47.93; P = .001). There was no difference between HFNC and FM in the lowest arterial oxygen content (MD, -23.90; 95% CI, -88.64 to 40.85; P = .47) and the lowest peripheral oxygenation saturation (MD, -0.47 with 95% CI, -5.07 to 4.12; P = .84). HFNC had a lower odd of discomfort than FM (OR, 0.13; 95% CI, 0.03-0.52; P = .004). There was no difference in the odds of aspiration of gastric contents between HFNC and FM (OR, 0.33; 95% CI, 0.01-8.21; P = .50). The risk of bias for our primary and secondary outcomes was low. The GRADE assessment for our primary outcome indicated a low level of certainty. For secondary outcomes, the GRADE assessment indicated a very low certainty for all outcomes except for patient discomfort, which was indicated as a moderate level of certainty.

CONCLUSIONS

There may be no difference between HFNC and FM preoxygenation in preventing oxygen desaturation <92% or the lowest oxygen saturation before intubation. Preparation remains important to prevent and manage desaturation during induction of obese patients.

Acute Respiratory Distress Syndrome in Pregnancy: Updates in Principles and Practice

Acute respiratory failure occurs in 0.05% to 0.3% of pregnancies and is precipitated by pulmonary and nonpulmonary insults. Acute respiratory distress syndrome (ARDS) is the rapid onset of hypoxemic respiratory failure associated with bilateral pulmonary opacities on chest imaging attributed to noncardiogenic pulmonary edema. The pathophysiological features of ARDS include hypoxemia, diminished lung volumes, and decreased lung compliance. While there is a paucity of data concerning ARDS in the pregnant individual, management principles do not vary significantly between pregnant and nonpregnant patients. The following review will discuss the diagnosis and management of the pregnant patient with ARDS.