Choice of anaesthesia for category-1 caesarean section in women with anticipated difficult tracheal intubation: the use of decision analysis

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.

Comparative Evaluation of Direct Laryngoscopy Versus GlideScope for the Purpose of Laryngoscopy Management and Intubation in Candidates of Cesarean Delivery with General Anesthesia

Background

The present study aimed at comparing the hemodynamic responses to laryngoscopy and initiation of intubation with either direct or video-assisted laryngoscopy.

Materials and Methods

This double-blind clinical trial was performed on 90 pregnant women candidates for cesarean section under general anesthesia. The participants were divided into two groups. In the first group, intubation was performed using direct Macintosh laryngoscope (MCL group). The second group underwent intubation using the GlideScope video laryngoscope (GSL group). Then, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), the percentage of the saturation of peripheral oxygen (SpO2), the time-to-intubation (TTI), and the number of intubation attempts were recorded.

Results

SBP, DBP, and MAP in the MCL group were significantly higher than GSL group 1, 3, and 5 min after laryngoscopy (P < 0.05). HR in the MCL group with the mean of 118.44 ± 15.53 bpm was significantly higher than that the GSL group with the mean of 110.11 ± 16.68 bpm only 3 min after laryngoscopy (P = 0.016). The TTI in the MCL group was significantly longer than that of the GSL group (12.80 ± 1.86 vs. 10.15 ± 2.61; P = 0.001). The frequency of the first intubation attempt in the GSL group with 91.1% was significantly higher than that the MCL group with 84.4% (P = 0.003).

Conclusion

It seems that the GSL technique is a better choice to conduct laryngoscopy with more success in intubation and a higher stability of the patients' hemodynamic status.

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.

General Anesthesia for Cesarean Delivery for Thrombocytopenia in Hypertensive Disorders of Pregnancy: Findings From the Obstetric Airway Management Registry

BACKGROUND

In resource-limited environments, spinal anesthesia (SA) is preferred for cesarean delivery. In women at risk of spinal epidural hematoma, particularly those with hypertensive disorders of pregnancy, thrombocytopenia should be excluded before neuraxial blockade. In the context of emergency surgery for fetal distress, this investigation may be hampered by laboratory services being unavailable or off-site.

METHODS

The Obstetric Airway Management Registry (ObAMR) is currently active across all anesthesia training institutions affiliated with the University of Cape Town. This multicenter observational study aimed to estimate the proportion of patients receiving general anesthesia (GA) for either confirmed or suspected thrombocytopenia, which was not excluded due to unavailability of laboratory results. To establish the number of GA uses that may have been avoided if platelet counts were available, we retrospectively searched for subsequent platelet counts in patients for whom thrombocytopenia was suspected. An algorithm was proposed, including a simple decision aid for estimating risk versus benefit of SA versus GA, to be followed in the setting of hypertensive disorders of pregnancy and thrombocytopenia.

RESULTS

Thrombocytopenia was the indication for GA in 100 of 591 patients (16.9%) captured in the registry. In total, 48 of 591 (8.1%) had confirmed thrombocytopenia, and 52 of 591 (8.8%) had suspected thrombocytopenia. Of these patients, 91 of 100 had a hypertensive disorder of pregnancy. In the confirmed thrombocytopenia group, the indication for GA was a platelet count <75 × 109/L. In the suspected thrombocytopenia group, 46 of 52 (88.5%) platelet counts could be retrospectively traced. The median (interquartile range) platelet count was 178 × 109/L (93 - 233 × 109/L), and platelets exceeded 75 × 109/L in 41 of 46 patients (89.1%). In the 5 of 46 patients with retrospectively confirmed thrombocytopenia, 2 had hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome, 2 had antepartum hemorrhage with preeclampsia, and 1 had isolated thrombocytopenia with preeclampsia.

CONCLUSIONS

In 17% of patients, the indication for GA was thrombocytopenia. Of these, 52 of 100, or nearly 9% of the total of 591, received GA because a platelet count was unavailable at the time of surgery. The importance of early laboratory assessment, when available, should be emphasized. Overall, 41 of 591 (6.9%) had a platelet count >75 × 109/L and would not have needed GA if their platelet count had been known. After following the constructed algorithm and applying the decision aid to assess risk and benefit, there may be circumstances in which the clinician justifiably opts for SA when a platelet count is indicated but unavailable.

Analysis of Airway Management for Cesarean Delivery: Use of Risk and Proportion Differences

OBJECTIVES

Securing the parturient airway is essential during general anesthesia for cesarean delivery. The purpose of this study was to compare inferior airway views provided by the use of three commonly available laryngoscopy blades-Macintosh, Miller, or Glidescope Mac-Style-to the incidence of difficult orotracheal intubation.

METHODS

Following institutional review board approval, data from 449 electronic medical records in parturients undergoing general anesthesia for cesarean delivery were extracted during a 6-year period. The association of these blades with difficult orotracheal intubation was analyzed with risk and proportion differences measures of effect size.

RESULTS

The overall incidence of difficult orotracheal intubation was 4.2% (95% confidence interval 2.7 - 6.5%), with 6 failed orotracheal intubations (5 laryngeal mask airways rescues and 1 mask rescue). Clinically important increases in risk differences for difficult orotracheal intubation were observed in parturients with restricted mouth openings, modified Mallampati III and IV views, and reduced thyromental distances. When modified Cormack-Lehane views were grouped into III and IV versus I and II cohorts; proportion differences for difficult orotracheal intubation were dependent upon the type of blade used, with the Miller blade providing the lowest proportion difference.

CONCLUSIONS

Miller blade laryngoscopy provided the lowest proportion difference for difficult orotracheal intubation during general anesthesia for cesarean delivery. Miller blade laryngoscopy provides effective procurement of the parturient airway.

Comparison of videolaryngoscopy and direct laryngoscopy for tracheal intubation in obstetrics: a mixed-methods systematic review and meta-analysis

PURPOSE

The incidence of difficult and failed intubation is higher in obstetrical patients than in the general population because of anatomic and physiologic changes in pregnancy. Videolaryngoscopy improves the success rate of intubation and reduces complications when compared with direct laryngoscopy in adults; however, it is not known whether this extends to obstetrical surgery. The aim of this study was to examine the efficacy, efficiency, and safety of videolaryngoscopy compared with direct laryngoscopy in obstetrics.

SOURCE

Central, CINAHL, Embase, MEDLINE and Web of Science databases were searched from inception to 27 May 2020 with no restrictions. Inclusion criteria included randomized-controlled trials (RCTs), observational studies, case series, and case reports that reported the application of videolaryngoscopy to intubate the trachea in pregnant patients having general anesthesia.

PRINCIPAL FINDINGS

Overall, four RCTs with 428 participants, nine observational studies, and 35 case reports/series with 100 participants were included. On meta-analysis of three trials, the co-primary outcomes of first-attempt success rate (risk ratio, 1.02; 95% confidence intervals [CI], 0.98 to 1.06; P = 0.29; I2 = 0%) and time to tracheal intubation (mean difference, 1.20 sec; 95% CI, -6.63 to 9.04; P = 0.76; I² = 95%) demonstrated no difference between videolaryngoscopy and direct laryngoscopy in parturients without difficult airways. Observational studies and case reports underline the role of videolaryngoscopy as a primary choice when difficulty with tracheal intubation is expected or as a rescue modality in difficult or failed intubations.

CONCLUSIONS

Evidence for the utility of videolaryngoscopy continues to evolve but supports its increased adoption in obstetrics where videolaryngoscopes should be immediately available for use as a first-line device.

TRIAL REGISTRATION

PROSPERO (CRD42020189521); registered 6 July 2020.

Comparison of postoperative pulmonary outcomes in patients undergoing cesarean section under general and spinal anesthesia: A single-center audit

Introduction:

Regional anesthesia (RA), i.e., spinal or epidural anesthesia when performed for lower segment cesarean section (LSCS) provides excellent surgical conditions, avoiding manipulation of the maternal airway, maternal satisfaction, and good postoperative analgesia. However, in situations like fetal distress (fetal heart rate abnormalities), obstetric indications (abruption of placenta, antenatal placental bleeding, cord prolapse), maternal refusal for RA, contraindications to neuraxial anesthesia (anticoagulation, coagulopathy), and at times failed RA general anesthesia (GA) is administered. Several studies have demonstrated greater mortality and morbidity when LSCS is done under GA when compared to neuraxial block.

Methods:

After necessary approval, we retrospectively reviewed data over a period of 1 year (January 1, 2020–December 31, 2020) of LSCS under GA versus RA. The aim was to compare immediate postoperative complications, postoperative pulmonary complications up to 4 weeks from the time of elective and emergency LSCS under either RA or GA.

Results:

Of the 753 patients who underwent LSCS in one calendar year, there were 272 (36.12%) elective and 481 (63.87%) emergency LSCS. The number of elective LSCS under neuraxial block was 219 (29.09%) and under GA were 53 (7.03%). Emergency LSCS done under neuraxial block were 268 (35.59%) and under GA were 213 (28.28%). There were no adverse pulmonary complications at the end of 4 weeks in either group.

Conclusion:

RA provides maternal satisfaction and excellent perioperative analgesia in LSCS. Safe GA can be achieved with proper airway planning, if case is attended by at least two anesthesiologist with adequate preoperative fasting, and postoperative monitoring.

Hypoxaemia during tracheal intubation in patients with hypertensive disorders of pregnancy: analysis of data from an obstetric airway management registry

BACKGROUND

In South Africa, hypertensive disorders of pregnancy are the leading cause of maternal mortality. More than 50% of anaesthesia-related maternal deaths are attributed to complications of airway management. We compared the prevalence and risk factors for hypoxaemia during induction of general anaesthesia in parturients with and without hypertensive disorders of pregnancy. We hypothesised that hypertensive disorders of pregnancy are associated with desaturation during tracheal intubation.

METHODS

Data from 402 cases in a multicentre obstetric airway management registry were analysed. The prevalence of peri-induction hypoxaemia (SpO₂ <90%) was compared in patients with and without hypertensive disorders of pregnancy. Quantile regression of SpO₂ nadir was performed to identify confounding variables associated with, and mediators of, hypoxaemia.

RESULTS

In the cohort of 402 cases, hypoxaemia occurred in 19% with and 9% without hypertension (estimated risk difference, 10%; 95% CI 2% to 17%; P=0.005). Quantile regression demonstrated a lower SpO₂ nadir associated with hypertensive disorders of pregnancy as body mass index increased. Room-air oxygen saturation, Mallampati grade, and number of intubation attempts were associated with the relationship.

CONCLUSIONS

Clinically significant oxygen desaturation during airway management occurred twice as often in patients with hypertensive disorders of pregnancy, compounded by increasing body mass index. Intermediary factors in the pathway from hypertension to hypoxaemia were also identified.

The effects of labor on airway outcomes with Supreme™ laryngeal mask in women undergoing cesarean delivery under general anesthesia: a cohort study

BACKGROUND

Pregnancy is associated with higher incidence of failed endotracheal intubation and is exacerbated by labor. However, the influence of labor on airway outcomes with laryngeal mask airway (LMA) for cesarean delivery is unknown.

METHODS

This is a secondary analysis of a prospective cohort study on LMA use during cesarean delivery. Healthy parturients who fasted > 4 h undergoing Category 2 or 3 cesarean delivery with Supreme™ LMA (sLMA) under general anesthesia were included. We excluded parturients with BMI > 35 kg/m2, gastroesophageal reflux disease, or potentially difficult airway (Mallampati score of 4, upper respiratory tract or neck pathology). Anesthesia and airway management reflected clinical standard at the study center. After rapid sequence induction and cricoid pressure, sLMA was inserted as per manufacturer's recommendations. Our primary outcome was time to effective ventilation (time from when sLMA was picked up until appearance of end-tidal carbon dioxide capnography), and secondary outcomes include first-attempt insertion failure, oxygen saturation, ventilation parameters, mucosal trauma, pulmonary aspiration, and Apgar scores. Differences between labor status were tested using Student's t-test, Mann-Whitney U test, or Fisher's exact test, as appropriate. Quantitative associations between labor status and outcomes were determined using univariate logistic regression analysis.

RESULTS

Data from 584 parturients were analyzed, with 37.8% in labor. Labor did not significantly affect time to effective ventilation (mean (SD) for labor: 16.0 (5.75) seconds; no labor: 15.3 (3.35); mean difference: -0.65 (95%CI: - 1.49 to 0.18); p = 0.1262). However, labor was associated with increased first-attempt insertion failure and blood on sLMA surface. No reduction in oxygen saturation or pulmonary aspiration was noted.

CONCLUSIONS

Although no significant increase in time to effective ventilation was noted, labor may increase the number of insertion attempts and oropharyngeal trauma with sLMA use for cesarean delivery in parturients at low risk of difficult airway. Future studies should investigate the effects of labor on LMA use in high risk parturients.

TRIAL REGISTRATION

The study was prospectively registered at clinicaltrials.gov ( NCT02026882 ) on 3 January 2014.

Rescue supraglottic airway devices at caesarean delivery: What are the options to consider?

Tracheal intubation is considered the gold standard means of securing the airway in obstetric general anaesthesia because of the increased risk of aspiration. Obstetric failed intubation is relatively rare. Difficult airway guidelines recommend the use of a supraglottic airway device to maintain the airway and to allow rescue ventilation. Failed intubation is associated with a further increased risk of aspiration, therefore there is an argument for performing supraglottic airway-guided flexible bronchoscopic intubation (SAGFBI). The technique of SAGFBI has a high success rate in the non-obstetric population, it protects the airway and it minimises task fixation on repeated attempts at laryngoscopic tracheal intubation. However, after failed intubation via laryngoscopy, there is a lack of specific recommendations or indications for SAGFBI in current obstetric difficult airway guidelines in relation to achieving tracheal intubation. Our narrative review explores the issues pertaining to airway management in these cases: the use of supraglottic airway devices and the techniques of, and technical issues related to, SAGFBI. We also discuss the factors involved in the decision-making process as to whether to proceed with surgery with the airway maintained only with a supraglottic airway device, or to proceed only after SAGFBI.

Anesthesia for Urgent Cesarean Section

Cesarean section (CS) is a common surgical procedure worldwide. The anesthesiologist is responsible, together with obstetrician and neonatologist, for safe perioperative management. A continuum of risk exists for urgent CS. The decision-to-delivery interval is an important audit tool, to ensure international standards are upheld and good outcomes for mother and neonate are achieved. Urgent CS may be performed under either GA or RA, with benefits and risks attributable to each. Specific clinical scenarios require an individualized approach to anesthesia, including hemorrhage, hypertensive disorders, cardiac disease, the difficult airway and fetal compromise. Ongoing training is integral to the provision of safe anesthesia.

The decision to delivery interval in emergency caesarean sections: Impact of anaesthetic technique and work shift

Background: One important task of the emergency anaesthesia service is to provide rapid, safe and effective anaesthesia for emergency caesarean sections (ECS). A Decision to Delivery Interval (DDI) <30 minutes for ECS is a quality indicator for this service. The aim of this study was to assess the DDI and the impact of chosen anaesthetic technique (general anaesthesia (GA), spinal anaesthesia (SPA) with opioid supplementation, or "top-up" of labour epidural analgesia (tEDA) with local anaesthesia and fentanyl mixture) and work shift for ECS at Danderyds Hospital, Sweden. Methods: A retrospective chart review of ECS at Danderyds Hospital was performed between January and October 2016. Time between decision for CS, start of anaesthesia, time for incision and delivery, type of anaesthetic technique, and time of day, working hours or on call and day of week, Monday - Friday, and weekend was compiled and analysed. Time events are presented as mean ± standard deviation. Non-parametric tests were used. Results: In total, 135 ECS were analysed: 92% of the cases were delivered within 30 minutes and mean DDI for all cases was 17.3±8.1 minutes. GA shortened the DDI by 10 and 13 minutes compared to SPA and tEDA (p<0.0005). DDI for SPA and tEDA did not differ. There was no difference in DDI regarding time of day or weekday. Apgar <7 at 5' was more commonly seen in ECS having GA (11 out of 64) compared to SPA (2/30) and tEDA (1/41) (p<0.05). Conclusion: GA shortens the DDI for ECS, but the use of SPA as well as tEDA with opioid supplementation maintains a short DDI and should be considered when time allows. Top-up epidural did not prolong the DDI compared to SPA. The day of week or time of ECS had no influence on the anaesthesia service as measured by the DDI.

The decision to delivery interval in emergency caesarean sections: Impact of anaesthetic technique and work shift

Background: One important task of the emergency anaesthesia service is to provide rapid, safe and effective anaesthesia for emergency caesarean sections (ECS). A Decision to Delivery Interval (DDI) <30 minutes for ECS is a quality indicator for this service. The aim of this study was to assess the DDI and the impact of chosen anaesthetic technique (general anaesthesia (GA), spinal anaesthesia (SPA) with opioid supplementation, or "top-up" of labour epidural analgesia (tEDA) with local anaesthesia and fentanyl mixture) and work shift for ECS at Danderyds Hospital, Sweden. Methods: A retrospective chart review of ECS at Danderyds Hospital was performed between January and October 2016. Time between decision for CS, start of anaesthesia, time for incision and delivery, type of anaesthetic technique, and time of day, working hours or on call and day of week, Monday - Friday, and weekend was compiled and analysed. Time events are presented as mean ± standard deviation. Non-parametric tests were used. Results: In total, 135 ECS were analysed: 92% of the cases were delivered within 30 minutes and mean DDI for all cases was 17.3±8.1 minutes. GA shortened the DDI by 10 and 13 minutes compared to SPA and tEDA (p<0.0005). DDI for SPA and tEDA did not differ. There was no difference in DDI regarding time of day or weekday. Apgar <7 at 5' was more commonly seen in ECS having GA (11 out of 64) compared to SPA (2/30) and tEDA (1/41) (p<0.05). Conclusion: GA shortens the DDI for ECS, but the use of SPA as well as tEDA with opioid supplementation maintains a short DDI and should be considered when time allows. Top-up epidural did not prolong the DDI compared to SPA. The day of week or time of ECS had no influence on the anaesthesia service as measured by the DDI.