Obstetric General Anaesthesia Research Articles

Are opioids safe for use in obstetric general anaesthesia?

The use of opioids during caesarean section has historically been avoided because of concerns regarding neonatal compromise. There is now more evidence regarding the safety and benefits of opioids in obstetric general anaesthesia, so should opioids be used during induction of anaesthesia for caesarean section?

Safe caesarean sections in South Africa: Is internship training sufficient?

Background. In Africa, the maternal mortality rate after caesarean section (CS) is 50 times higher than that in high-income countries. In South Africa (SA), women who undergo CS have a three times higher mortality rate than those who deliver vaginally. Anaesthetic complications and obstetric haemorrhage are major drivers of poor outcomes, and the case fatality rate for CS at district hospitals is particularly high. Objectives. To assess the adequacy of anaesthetic and obstetric internship training in preparing interns to perform CS independently and safely. Methods. This was an observational cross-sectional survey of all community service officers (CSOs) in KwaZulu-Natal (KZN), SA, in 2020. Data were collected via an electronic survey that comprised 68 questions in 4 domains, covering personal information, obstetric surgical training, obstetric anaesthetic training and support received as a CSO. Results. Surveys were sent to 228 CSOs in KZN, with 160 responses received (70% response rate). Respondents included participants from 8 medical schools and 33 internship facilities across the country. One in 8 interns (n=21/160) did not perform the required 10 CSs. Supervision in theatre was provided by an obstetric specialist for at least 1 CS in n=57/160 (35.62%; 95% confidence interval (CI) 28.54 - 43.39) participants, and n=45/160 (28.13%; 95% CI 21.66 - 35.64) interns never performed an emergency CS. Interns had limited opportunity to be the primary surgeon for complicated cases. Only 1/5 interns performed >5 obstetric general anaesthetics. Conclusions. This survey showed that there are deficiencies in the current CS-related training of interns in SA. A lack of exposure to adequate obstetric surgical training and obstetric general anaesthesia is likely to impact on the performance of CSOs and on the safety of the CS service provided at district hospitals. The content and quality of the CS-related intern training programme needs to be enhanced to improve the competence of CSOs. The Health Professions Council of South Africa (HPCSA)’s stipulations for internship training must be adhered to and should look to include simulation training, basic surgical skills courses and prioritisation of exposure to complicated surgical scenarios

Enhancing knowledge, skills, and comfort in providing anesthesia assistance during obstetric general anesthesia for operating room nurses: a prospective observational study.

Due to a nationwide shortage of anesthesia assistants, operating room nurses are often recruited to assist with theinduction of obstetric general anesthesia (GA). We developed and administered a training program and hypothesized there would be significant improvements in knowledge and skills in anesthesia assistance during obstetric GA by operating room nurses following training with adequate retention at six months. Following informed consent, all operating room nurses at our institution were invited to participate in the study. Baseline knowledge of participants was assessed using a 14-item multiple choice questionnaire (MCQ), and skills were assessed using a 12-item checklist scored by direct observation during simulated induction of GA. Next, a 20-min didactic lecture followed by a ten-minute hands-on skills station were delivered. Knowledge and skills were immediately reassessed after training, and again at six weeks and six months. The primary outcomes of this study were adequate knowledge and skills retention at six months, defined as achieving ≥ 80% in MCQ and ≥ 80% in skills checklist scores and analyzed using longitudinal mixed-effects linear regression. A total of 34 nurses completed the study at six months. The mean MCQ score at baseline was 8.9 (95% confidence interval [CI], 8.5 to 9.4) out of 14. The mean skills checklist score was 5.5 (95% CI, 4.9 to 6.1) out of 12. The mean comfort scores for assisting elective and emergency Cesarean deliveries were 3.6 (95% CI, 3.2 to 3.9) and 3.1 (95% CI, 2.7 to 3.5) out of 5, respectively. There was a significant difference in the mean MCQ and skills checklist scores across the different study periods (overall P value < 0.001). Post hoc pairwise tests suggested that, compared with baseline, there were significantly higher mean MCQ scores at all time points after the training program at six weeks (11.9; 95% CI, 11.4 to 12.4; P < 0.001) and at six months (12.0; 95% CI, 11.5 to 12.4; P < 0.001). The knowledge and skills of operating room nurses in providing anesthesia assistance during obstetric GA at our institution were low at baseline. Following a single 30-min in-house, anesthesiologist-led, structured training program, scores in both dimensions significantly improved. Although knowledge improvements were adequately retained for up to six months, skills improvements decayed rapidly, suggesting that sessions should be repeated at six-week intervals, at least initially.

Incidence of Accidental Awareness During General Anesthesia in Obstetrics: A Multicenter, Prospective Cohort Study

(Anaesthesia. 2021;76:759–776. [Epub January 12, 2021]) The occurrence of accidental awareness during general anesthesia (AAGA) for obstetric patients appears to be influenced by multiple factors. Underreporting may be at play when patients self-report AAGA while, conversely, overreporting may be happening following a “Brice” interview method due to potential oversensitivity of the tool. This study aimed to describe the occurrence, nature of, risk-factors, and psychological implications of AAGA for obstetric patients requiring surgery.

From Hypnos to Ephialtes: Waking Up to the Consequences of Accidental Awareness During Obstetric General Anaesthesia

(Anaesthesia. 2021;76:736–739. [Epub February 9, 2021]) This editorial discusses accidental awareness during general anesthesia (AAGA). A recent study on AAGA by Odor et al is not only praised for its thorough investigation of AAGS using a large sample size, but its findings are emphasized: AAGA occurrence was 3 times higher than self-reported rates have indicated. The study of interest also found posttraumatic stress disorder (PTSD) in one third of AAGA patients (42 times more likely than non-AAGA patients). The authors point out that future studies could include a larger-sample, international trial, however, the study investment may not be worth the study outcomes. Instead, a focus should be placed on changing health care management patterns associated with AAGA.

P.32 Evaluating the role of local ODP teaching sessions in improving the provision of general anaesthesia in obstetrics

P.32 Evaluating the role of local ODP teaching sessions in improving the provision of general anaesthesia in obstetrics

Comparison of the median effective concentration (EC50) and effect of sevoflurane with or without remifentanil in cesarean section with supreme laryngeal mask under narcotrend monitoring: a randomized trial.

Remifentanil combined with sevoflurane is a standard protocol for obstetric general anesthesia (GA). In this study, we performed a randomized clinical trial to evaluate whether remifentanil has an effect on the median effective concentration (EC50) of sevoflurane and compare anesthetic outcomes of them in cesarean section with Supreme™ laryngeal mask airway (SLMA) under narcotrend monitoring. Ninety parturients with singleton births undergoing elective cesarean delivery (CD) with initial inhaled 1.0 minimum alveolar concentration (MAC) sevoflurane for anesthesia maintenance were assigned to three groups randomly and evenly: Group A (0.05 µg·kg-1·min-1 remifentanil combined with sevoflurane), Group B (0.1 µg·kg-1·min-1 remifentanil combined with sevoflurane), and Group C (normal saline combined with sevoflurane). Narcotrend was used to monitor the depth of anesthesia during the operation, with the level of anesthesia depth controlled within the D-E stage. The EC50 of sevoflurane was determined by Dixon's sequential method. The Narcotrend index, amount of bleeding, neonatal Apgar score, and corresponding treatment measures in the three groups were recorded. The results showed that the estimated EC50 of sevoflurane for obstetric GA was 0.80 MAC (95% CI: 0.63-0.95 MAC) in group A, 0.82 MAC (95% CI: 0.63-0.96 MAC) in group B, and 0.80 MAC (95% CI: 0.63-0.95 MAC) in group C. There was no statistically significant difference in the estimated EC50 of sevoflurane, time to wakefulness, Apgar score, amount of intraoperative bleeding, and postoperative bleeding within 24 hours between the three groups (all P>0.05). The addition of remifentanil at 0.05-0.1 µg·kg-1·min-1 did not change the EC50 of sevoflurane and anesthetic quality. The concentration of inhaled anesthetics can be minimized with Narcotrend monitoring. Chinese Clinical Trial Registry ChiCTR2000034512.

Difficult and Failed Tracheal Intubation in Obstetrics: A Seven-year Review in a Saudi Maternity Hospital

Background: Airway difficulty is a major contributor to mortality and morbidity during caesarean section (CS) under general anaesthesia. Though general anaesthesia is safe, the changes associated with pregnancy make securing airway more difficult. The purpose of this study was to investigate the pattern and factors associated with airway difficulty in the parturient in the region. Methods: This was a retrospective, descriptive study of parturients who suffered airway difficulty during caesarean section under general anaesthesia over seven-year period. Their medical records were reviewed and data collected included total CS done under general anaesthesia, age, weight, nature of airway difficulty, coexisting diseases, and timing of surgery, outcomes and Apgar scores. Data was analysed using SPSS version 23 for Windows®. Results: General anaesthesia was used in 51.3% of 10,275 CS with 42 documented as “difficult airway” giving 0.8% incidence and incidence ratio of 1:125. Failed intubation was recorded in 58% while difficult intubation was 42% of those with difficult airway. Among these, the CS was in 55% of cases “emergent”. The mean age was 33.32±5.96 years. The weight ranged from 60 to 163kg. Over 58% weighed more than 90kg. In 50% of cases, the airway was rescued with LMA and in 50%, reintubation succeeded. Outcome was good for mother and fetus in all cases. Conclusion: Obstetric airway difficulty remains a valid concern. Effort should be made to use regional anaesthesia to reduce the risk. High awareness and preparation during obstetric general anaesthesia are recommended.

P.92 Keep it simple!

Introduction: Obstetric general anaesthesia (OGA) comes with the possible risk of aspiration. The gold standard for airway management is a rapid sequence induction and tracheal intubation. While failed intubation in obstetrics is uncommon (1 in 443) the consequences are serious. [1] Kinsella SM, Winton Al, Mushambi MC, et al. Failed tracheal intubation during obstetric general anaesthesia: a literature review. Int J Obstet Anesth 2015; 24::356-74. Google Scholar The use of a supraglottic airway device (SAD) in obstetrics as rescue allows for ventilation/oxygenation and it can be used as a route to securing the airway. 2 Wong P, Sng BL, Lim WY. Rescue supraglottic airway devices at caesarean delivery: What are the options to consider? Int J Obstet Anesth 2020; 42:65-75. Google Scholar , 3 Metodiev Y, Mushambi M. Supraglottic airway devices for Caesarean delivery under general anaesthesia: for all, for none, or for some? Br J Anaesth 2020; 125: e7ee11. Google Scholar Our aims were to observe local approaches to failed intubation in OGAs and standardise the use of fibreoptic intubation (FOI) through SAD in a cannot intubate/can ventilate scenario.

P.105 Survey of drugs used in obstetric emergency general anaesthesia in South Yorkshire Teaching Hospitals

P.105 Survey of drugs used in obstetric emergency general anaesthesia in South Yorkshire Teaching Hospitals

P.79 A care bundle to improve perioperative care of women having caesarean section under general anaesthesia using appreciative methodology

Introduction: Two failed intubations at our Trust highlighted the need to examine current practice for obstetric general anaesthesia. The aim of this medical student project was to examine the entire care pathway of women undergoing a general anaesthetic for caesarean section (CS) and introduce interventions to improve care. The first element included optimising rates of first-time intubation;the second involved optimisation of post-op analgesia;the third investigated follow-up for women who had difficult/failed intubations perinatally. Methods: A blended methodology was used: traditional ’PDSA’ quality improvement methods were employed with appreciative inquiry (AI). AI is an approach to organisational improvement that focuses on strengths and assets, rather than the traditional approach of focussing only on adverse incidents or failures. On account of COVID, planned face-to- face interviews and direct observation of practice could not proceed. Questions where therefore emailed to all staff. Questions were appreciative and thus focussed the responder on situations where care had gone well, as well as identifying areas for improvement. Stakeholders were actively encouraged to be creative and submit their ideas for improvement as part of the co-development of the service. Results: Regarding improving rates of successful intubation, 23 anaesthetists and ODP’s responded. The most important factors in successful intubation were thought to be: systematic approach, patient positioning;equipment preparation and a calm environment. Interestingly, ’leadership’ and ’procedural skill’ were mentioned least frequently. Suggestions for enhancing safety included clearly communicated plans for difficult/failed intubations. Sixty-five percent of respondents requested further teaching on obstetric difficult airway management;with suggestions such as 30 second simulation drills, revision of OAA/DAS and changing attitudes towards obstetric anaesthesia so that trainees are less fearful. The post-operative questionnaire gained 31 responses. The current post-CS advice and leaflet was felt to be inadequate (58%). The need for improved advice on pain management and activity was highlighted. Common practice following difficult intubation included face-to-face discussions with the patient and logging on the Difficult Airway Society database. Some wrote to the GP. Discussion: Based on the findings, a number of action plans have been implemented: 1) Regular 30 second MDT simulated intubation drills 2) new easy-read, obstetric intubation prompt (to be used in conjunction with OAA/DAS flowchart) to be visible in maternity theatres 3) Generation of rapid pre- intubation checklist 4) Publication of a new leaflet to address pain control and activity post LSCS, to include helpful quotes from past patients. 5) Production of a checklist to ensure standardisation of process for women who have had difficult/failed intubation.

P.47 Airway assessment on the labour ward

Introduction: The incidence of difficult intubation in the obstetric population is 1 in 250. [1] McDonnell NJ, Paech MJ, Clavsi OM, et al, the ANZCA Trails Group. Difficult and failed intubation in obstetric anaesthesia: an observational study of airway management and complications associated with general anaesthesia for caesarean section. Int J Obstet Aneth 2008;17:292-7. Google Scholar With the infrequent use of general anaesthesia, the anaesthetist must be prepared for potential difficulty. [2] Searle RD, Lyons G. Vanishing experience in training for obstetric general anaesthesia: an observational study. Int J Obstet Anesth 2008;17:233-7. Google Scholar This includes performing a detailed airway assessment prior to administering labour analgesia or anaesthesia. Previous departmental data found that 70% of patients undergo a comprehensive airway assessment. Recently the anaesthetic chart was modified to specifically indicate the presence or absence of a potentially difficult airway. We aimed to re-audit how comprehensive the initial airway assessment was, and whether potentially difficult airways were being highlighted.

P.95 Trends in rocuronium use in obstetric anaesthesia and monitoring and documentation of neuromuscular block

Introduction: Since the recommendations of NAP4, NAP5 and the joint OAA/DAS difficult airway guidelines, many aspects of the traditional obstetric general anaesthesia (GA) have been challenged. Alongside the availability of the rapidly acting reversal agent sugammadex, the use of rocuronium for RSI in obstetric patients has increased significantly. Prior to extubation, patients should have a train of four ratio of ⩾ 90%. Qualitative neuromuscular monitors cannot detect this degree of recovery and quantitative neuromuscular monitors should be used.

Anticipated Difficult Airway During Obstetric General Anesthesia: Narrative Literature Review and Management Recommendations

(Anaesthesia. 2020;75:945–961) The Obstetric Anaesthetists’ Association (OAA) and the Difficult Airway Society (DAS) issued guidelines for difficult tracheal intubation in pregnant women in 2015. Many other organizations have published guidelines for difficult intubation in non-obstetric patients. This report aimed to review literature on difficult intubation in pregnant women and specifically address antenatal multidisciplinary planning for patients with anticipated and/or known difficult airway including awake tracheal intubation.

Choice of Hypnotic Drug for Obstetric and Non-obstetric General Anaesthesia. Comment on Br J Anaesth 2020; 125: e81-7

(Br J Anaesth. 2020;125:e452–e453) Airway management conditions are affected by many factors, including the anesthetic induction drugs used. A recent study by Bonnett and colleagues in patients undergoing non-elective Cesarean delivery found co-administering propofol with succinylcholine resulted in superior intubating conditions compared with the co-administration of thiopental with succinylcholine. These results support the use of propofol rather than thiopental in obstetric general anesthesia.

Incidence of accidental awareness during general anaesthesia in obstetrics: a multicentre, prospective cohort study.

General anaesthesia for obstetric surgery has distinct characteristics that may contribute towards a higher risk of accidental awareness during general anaesthesia. The primary aim of this study was to investigate the incidence, experience and psychological implications of unintended conscious awareness during general anaesthesia in obstetric patients. From May 2017 to August 2018, 3115 consenting patients receiving general anaesthesia for obstetric surgery in 72 hospitals in England were recruited to the study. Patients received three repetitions of standardised questioning over 30days, with responses indicating memories during general anaesthesia that were verified using interviews and record interrogation. A total of 12 patients had certain/probable or possible awareness, an incidence of 1 in 256 (95%CI 149-500) for all obstetric surgery. The incidence was 1 in 212 (95%CI 122-417) for caesarean section surgery. Distressing experiences were reported by seven (58.3%) patients, paralysis by five (41.7%) and paralysis with pain by two (16.7%). Accidental awareness occurred during induction and emergence in nine (75%) of the patients who reported awareness. Factors associated with accidental awareness during general anaesthesia were: high BMI (25-30kg.m-2 ); low BMI (<18.5kg.m-2 ); out-of-hours surgery; and use of ketamine or thiopental for induction. Standardised psychological impact scores at 30days were significantly higher in awareness patients (median (IQR [range]) 15 (2.7-52.0 [2-56]) than in patients without awareness 3 (1-9 [0-64]), p=0.010. Four patients had a provisional diagnosis of post-traumatic stress disorder. We conclude that direct postoperative questioning reveals high rates of accidental awareness during general anaesthesia for obstetric surgery, which has implications for anaesthetic practice, consent and follow-up.

General anaesthetic and airway management practice for obstetric surgery in England: a prospective, multicentre observational study.

There are no current descriptions of general anaesthesia characteristics for obstetric surgery, despite recent changes to patient baseline characteristics and airway management guidelines. This analysis of data from the direct reporting of awareness in maternity patients' (DREAMY) study of accidental awareness during obstetric anaesthesia aimed to describe practice for obstetric general anaesthesia in England and compare with earlier surveys and best-practice recommendations. Consenting patients who received general anaesthesia for obstetric surgery in 72 hospitals from May 2017 to August 2018 were included. Baseline characteristics, airway management, anaesthetic techniques and major complications were collected. Descriptive analysis, binary logistic regression modelling and comparisons with earlier data were conducted. Data were collected from 3117 procedures, including 2554 (81.9%) caesarean deliveries. Thiopental was the induction drug in 1649 (52.9%) patients, compared with propofol in 1419 (45.5%). Suxamethonium was the neuromuscular blocking drug for tracheal intubation in 2631 (86.1%), compared with rocuronium in 367 (11.8%). Difficult tracheal intubation was reported in 1 in 19 (95%CI 1 in 16-22) and failed intubation in 1 in 312 (95%CI 1 in 169-667). Obese patients were over-represented compared with national baselines and associated with difficult, but not failed intubation. There was more evidence of change in practice for induction drugs (increased use of propofol) than neuromuscular blocking drugs (suxamethonium remains the most popular). There was evidence of improvement in practice, with increased monitoring and reversal of neuromuscular blockade (although this remains suboptimal). Despite a high risk of difficult intubation in this population, videolaryngoscopy was rarely used (1.9%).

A prospective, up-down sequential allocation study investigating the effectiveness of vital capacity breaths using high-flow nasal oxygenation versus a tight-fitting face mask to pre-oxygenate term pregnant women

BackgroundThe role of high flow nasal oxygenation (HFNO) for pre-oxygenation before obstetric general anaesthesia remains unclear. This study aimed to determine the number of vital capacity breaths using HFNO required to pre-oxygenate 90% of parturients to an end-tidal oxygen concentration fraction (FETO2) of ≥0.90 (termed EN90). MethodsUsing up-down, sequential allocation trial design, volunteer term parturients undergoing caesarean delivery were investigated with HFNO with their mouth closed, followed by mouth open, and if FETO2 ≥0.90 was not achieved after a maximum of 20 vital capacity breaths, pre-oxygenation was attempted with a face mask. The primary outcome was the number of vital capacity breaths required using HFNO (mouth open and closed) to achieve EN90. Secondary outcomes included assessment of EN90 using mouth open versus mouth closed and face mask pre-oxygenation, maternal satisfaction and evaluation of fetal cardiotocography. ResultsTwenty women at term were recruited. Successful pre-oxygenation occurred in 4 (20%), 3 (15%) and 14 (70%) women with HFNO mouth closed, HFNO mouth open, and via face mask respectively. At up to 20 vital capacity breaths, face mask pre-oxygenation was more successful at achieving EN90 compared with both HFNO with a closed (P=0.006) or open (P=0.001) mouth. Closed mouth HFNO did not outperform open mouth pre-oxygenation. ConclusionFace mask pre-oxygenation is more effective at achieving EN90 compared with to HFNO within a clinically acceptable number of vital capacity breaths. Further studies are needed to determine the role of HFNO in optimising the time before desaturation and for apnoeic oxygenation in term parturients.

Implementation and initial validation of a multicentre obstetric airway management registry

Background: In Africa, maternal mortality after caesarean delivery is 50 times greater than in high-income countries. In South Africa, more than 50% of anaesthesia-related maternal mortality is attributed to failure to protect the airway. We implemented an obstetric airway management registry, to facilitate future improvements in management and outcomes. Methods: A prospective electronic registry was established at three obstetric sites in Cape Town, recording airway management for all general anaesthetics from 20 weeks gestation to seven days post-partum. Perioperative descriptive data are entered using a web-based smartphone-enabled platform. To quantify the reliability of capture, we compared the first 200 records in the registry to theatre logbooks. We used summary statistics to describe our obstetric anaesthesia population, and details relevant to airway management. Results: The first 200 cases were recorded from September 2018 to January 2019. According to theatre logbooks, this represented 80% of cases performed. Major indications for general anaesthesia included severe fetal distress/bradycardia (21%), failed neuraxial technique (19%), coagulopathy (19%), and abnormal placentation (12%). A third of patients had hypertensive disorders of pregnancy, and 6% had imminent/confirmed eclampsia. Forty per cent were in active labour. On airway assessment, Mallampati grade was 3 or 4 in 29% of patients, and mouth opening, thyromental distance and mandibular protrusion limited in 10%, 8% and 8% respectively. Cormack-Lehane grade IIb and III views were encountered in 6% and 2% respectively, with no grade IV views. Desaturation below 90% occurred in 12% of patients. There were two cases (1%) of failed intubation with supraglottic airway rescue, and no emergency surgical airways performed. Conclusion: An obstetric airway management registry was successfully implemented. Clinically significant hypoxaemia occurred commonly during general anaesthesia, with a high incidence of difficult intubation predictors and desaturation. The registry will guide research aimed at improving safety during general anaesthesia in obstetrics.

Anticipated difficult airway during obstetric general anaesthesia: narrative literature review and management recommendations.

We reviewed the literature on management of general and regional anaesthesia in pregnant women with anticipated airway difficulty. We identified 138 publications comprising 158 cases; these either described equipment or techniques for the provision of general anaesthesia, or the management of women with regional analgesia or anaesthesia, with the aim of avoiding general anaesthesia. Most of the former group described women requiring caesarean section alone, or in combination with other surgery, which was sometimes airway-related. Management techniques were largely similar to those in non-obstetric patients requiring surgery who have airway difficulties, although suggested differences related to physiological changes of pregnancy and avoidance of nasal intubation. In the reports discussing regional anaesthesia, consideration was often given to the possible requirement for urgent out-of-hours anaesthetic intervention, and the predicted difficulty of management of general anaesthesia should it be required. In a number of reported cases, multidisciplinary planning led to the conclusion that elective caesarean section should be performed in order to avoid emergency airway management. Based on this literature review, we advise antenatal planning that includes: assessment of the patient's clinical characteristics; consideration of the equipment and personnel available to provide safe airway management out-of-hours; and elective caesarean section should these be lacking. If general anaesthesia is required, a risk assessment must be made as to the probability of safe airway management after the induction of anaesthesia, and awake tracheal intubation should be used if this cannot be assured. Decision aids are provided to illustrate these points. Online appendices include a comprehensive compendium of case reports on the management of a number of rare syndromes and airway conditions.