Anaesthesia for ‘stat’ caesarean sections

One of the greatest challenges for the obstetric anaesthetist is to be called upon to provide support for an immediate caesarean delivery, typically in the situation of impending maternal–foetal demise. The potential problems here are legion; the unprepared anaesthetist may be compelled to administer general anaesthesia under less than ideal conditions to an unfasted patient. Indeed, data from the United Kingdom demonstrate that the rate of caesarean section for the indication of ‘foetal distress’ has escalated dramatically over the past 2 decades, from 6.4% in 1980 to 13% in 1999, and up to 24% in 2001. This could have been attributed in part to the greater ability to diagnose intra-partum foetal compromise rendered by the enhanced sophistication of modern peri-partum monitoring. The current obstetric practice, when taking the medico-legal environment into account, may preclude a more conservative approach in the management of pregnancies with potential maternal–foetal complications. Regardless of cause, the urgency of which the situation is undertaken will undoubtedly have repercussions on the practice of anaesthesia; some degree of pressure to speedily, or worse, hastily administer general anaesthesia may be inevitable. This predicament can often be avoided if anaesthetists are informed earlier about the existence of such ‘high-risk’ cases before the rapid deterioration of the maternal–foetal clinical state and the decision for caesarean section is finally made. This would serve to enhance the preparedness of the anaesthetist and operating theatre staff in the eventuality of caesarean section.

Admittedly, some ‘stat’ caesarean sections may not be easily predicted and may present suddenly, such as a collapsed pregnant patient who requires a peri-mortem caesarean delivery when time is of the greatest essence. In this respect, previous audits have revealed that the longest delay in the decision-to-delivery interval is the time taken to transfer the patient to the operating theatre and the timely assembly of staff. This will continue to be a challenge but the principles of good clinical practice, including good teamwork, presence of well-trained staff and the implementation of a well-drilled system could potentially enhance the outcome of mother and baby. Our institution uses a public announcement system, a ‘stat’ caesarean section code activated only in the most desperate situation when an emergent caesarean section is required. This allows us to immediately mobilise the team members (comprising obstetricians, anaesthetists, neonatologists, nurses and health attendants) plus equipment for the processes of preparing and proceeding with surgery. Logistics aside, with the application of such a system, made possible only with appropriate training and drills, a remarkably short decision-to-delivery time could be potentially achieved.

In many other situations, such as the condition of a ‘non-reassuring foetal status’, it may be unnecessary, indeed undesirable, to rush the patient to an abdominal delivery. It is imperative for caregivers to recognise the urgency for a caesarean section, stratify risks accordingly and weigh the risk–benefit ratio before proceeding to deliver the baby without undue delay. Attempts have been made in the United Kingdom (UK) to classify the urgency of caesarean sections into 4 grades — (i) immediate threat to life of woman or foetus; (ii) maternal or foetal compromise which is not immediately life-threatening; (iii) needing early delivery but no maternal or foetal compromise; (iv) at a time to suite the patient and maternity team. This was found to be well accepted by both obstetricians and anaesthesiologists, thus enhancing multidisciplinary teamwork. However, the pathogenesis of intra-partum hypoxia, a common cause for making the call for a caesarean section in this case, is not yet fully understood and methods for its diagnosis are not without their limitations. Ironically, continuous intra-partum cardiotocographic monitoring could lead to an increase in caesarean sections and instrumental deliveries without apparent benefit in long-term neonatal outcomes. A maximum decision-to-delivery interval of 30 min for urgent caesarean sections has been adopted in the UK and North America as the minimum acceptable standard of care, although it is not apparent that neonates delivered beyond this time limit are always associated with a poorer outcome. However, conditions such as placental abruption or uterine rupture would necessitate an immediate delivery of the neonate, as any delay would, intuitively, result in a poor outcome for the baby. In other situations, the severity and gravity of the extent of maternal foetal insult may not be so apparent; hence, the need for good communication among caregivers is ever more vital to ensure patient-centric decision making and timely delivery. Active measures, such as positioning the mother in full left lateral position, giving oxygen, intravenous fluids and stopping the syntocinon infusion, might ameliorate foetal compromise, perhaps even avert a caesarean section.

In short, preparing a woman for emergency caesarean section is a multi-disciplinary task involving multiple steps and processes, including the timely assembly of staff. Good communication among obstetricians, midwives and anaesthetists, and early involvement of senior staff for high-risk cases may prevent a ‘crash’ caesarean section. In the most recent report on the confidential enquiry in maternal and child health (CEMACH), general anaesthesia for caesarean section in the emergency setting constituted the major direct cause of maternal death due to anaesthesia. We could infer that it is desirable to avoid a ‘stat’ caesarean section if possible. Rushing the process of performing a caesarean section may unduly place the mother and the foetus under unnecessary risks; particularly, it might pressurise the anaesthetist to be inclined to administering a hurried general anaesthetic against his/her better judgement of providing a regional technique instead. Ideally, anaesthetists should be informed early if there are problems such as high-risk pregnancies, patients with co-existing morbidities or a poor cardiotocographic trace so that anaesthetic management plans can be made in advance, or a functioning epidural catheter inserted early in labour. Though it is important to audit performance indicators such as decision-to-delivery times, it might be more useful to look for ways and means to constantly improve upon the process and pathway of care in urgent caesarean sections.

General anaesthesia for emergency caesarean section–a vanishing art?

In spite of the increasing popularity of regional anaesthesia, general anaesthesia for an emergency caesarean section continues to be an important, direct cause of maternal mortality and morbidity. Since 1979, results from CEMACH reports for direct maternal deaths show a greater risk from general anaesthesia than from regional anaesthesia. Hawkins and colleagues also report these findings in North America. The American Society of Anesthesiology (ASA) Closed Claims Study has attributed many of these deaths to the inability to establish or maintain a patent airway during general anaesthesia. Maternal death in this instance is commonly attributed to the high incidence of difficult airway and aspiration pneumonitis. It is still mandatory for one to perform tracheal intubation when administering general anaesthesia to ‘protect’ the airway; tracheal intubation in these patients can be a very daunting task for anaesthetist. Soft-tissue oedema and the accumulation of adipose tissue around the airway in pregnancy may render the visualisation of the larynx very challenging during laryngoscopy. Mask ventilation is difficult, and the pregnant patient, particularly if obese, is very prone to rapid oxygen desaturations on induction of general anaesthesia. Even though the difficult airway can often be anticipated by clinical features such as a large neck circumference, thyromental distance and a high Mallampati score, none of these is completely reliable. Caregivers of the parturient (e.g., midwives, obstetricians and anaesthetic personnel) could be trained to be alert and recognise the presence of risk factors that place the parturients at increased risk for complications from general anaesthesia, and alert the anaesthetist when identified. Hence, it is important for institutions that provide obstetric anaesthesia to have appropriate ‘unanticipated difficult airway’ and ‘failed intubation’ protocols. One could potentially decrease maternal morbidity and mortality associated with the provision of general anaesthesia for caesarean section by calling for organised drills and mock airway codes specific for the obstetric population to enable caregivers to function as a team.

The issue of difficult airway during general anaesthesia has largely been circumvented by the increasing use of regional anaesthesia. Even though trainees may be very proficient in the conduct of spinal or epidural anaesthesia, they are usually not as familiar with handling a real-life difficult airway for caesarean section. Many anaesthetists may encounter a difficult airway for the first time when called upon to anaesthetise such a patient in an emergency. The challenge is in the difficulty to ramp up one’s capability to handle these cases when the exposure to general anaesthesia is limited in the normal situation. There is a constant struggle to maintain safety of general anaesthesia with the lack of experienced anaesthetists to undertake the task, especially in remote areas and developing countries where the overall numbers of trained anaesthetists are few, and regional techniques are widely used as it is deemed safer and cheaper for the parturient. The safety of anaesthesia will certainly be enhanced with the more widespread availability of critical monitoring tools, such as pulse oximetry, and the training of their usage in developing countries.

Indeed, there are some positive signs on the horizon. For example, the recent ASA closed claims analysis found that there were no fatalities due to failed intubation since 1999. This state of affairs could be attributed to an increased awareness of potential airway catastrophes at the time of general anaesthesia, more frequent usage of regional anaesthesia, improvements in the difficult airway algorithm and of the use of the laryngeal mask airway (LMA) as a ‘rescue’ airway in the event of a failed intubation. The usefulness of the LMA in this situation is generally very well accepted and has been incorporated into the ASA difficult airway protocol. The LMA has also been used selectively for elective caesarean section even though there is no evidence to support its routine use at this point in time. Although the LMA is easy to insert, there are potential issues with its use in obstetric anaesthesia, principally related to the potential risk of regurgitation and aspiration of gastric content. The LMA ProSeal™, which has a port that allows drainage of gastric contents apart from affording a better oropharyngeal seal, has been shown to be effective as a temporary airway for post-partum patients. There have also been several reports of the successful use of the ProSeal™ as the rescue airway for failed intubation during general anaesthesia for caesarean section, even though there are no reports of properly performed randomised controlled trials to examine its safety in this context. Nevertheless, it is important to include tools such as the LMA and ProSeal™ (among others such as intubating fibre-optic bronchoscope, gum elastic bougie and cricothyroidotomy set) in the ‘difficult airway’ trolley, in the event of unexpected difficult intubation. Novel video-laryngoscopic devices have also been shown to either shorten the time to tracheal intubation or improve the quality of oxygenation when compared with the traditional direct laryngoscope, although that there is a significant learning curve involved and experience is limited in maternity patients.

Moreover, the incidence of maternal mortality due to aspiration during delivery is now rare; this could be attributable to a heightened awareness of the increased risk, enforcement of fasting guidelines, institution of aspiration prophylaxis and the increasing trend for use of regional anaesthesia for caesarean section delivery. Even though there has been a drastic reduction in maternal deaths from aspiration over the past few decades (from 1:42000 births in the USA in the 1950s, to only two closed claims in the ASA database since the 1990s), it is still a potential risk that the obstetric anaesthetist should not dismiss.

General anaesthesia for emergency caesarean section–a vanishing art?

In spite of the increasing popularity of regional anaesthesia, general anaesthesia for an emergency caesarean section continues to be an important, direct cause of maternal mortality and morbidity. Since 1979, results from CEMACH reports for direct maternal deaths show a greater risk from general anaesthesia than from regional anaesthesia. Hawkins and colleagues also report these findings in North America. The American Society of Anesthesiology (ASA) Closed Claims Study has attributed many of these deaths to the inability to establish or maintain a patent airway during general anaesthesia. Maternal death in this instance is commonly attributed to the high incidence of difficult airway and aspiration pneumonitis. It is still mandatory for one to perform tracheal intubation when administering general anaesthesia to ‘protect’ the airway; tracheal intubation in these patients can be a very daunting task for anaesthetist. Soft-tissue oedema and the accumulation of adipose tissue around the airway in pregnancy may render the visualisation of the larynx very challenging during laryngoscopy. Mask ventilation is difficult, and the pregnant patient, particularly if obese, is very prone to rapid oxygen desaturations on induction of general anaesthesia. Even though the difficult airway can often be anticipated by clinical features such as a large neck circumference, thyromental distance and a high Mallampati score, none of these is completely reliable. Caregivers of the parturient (e.g., midwives, obstetricians and anaesthetic personnel) could be trained to be alert and recognise the presence of risk factors that place the parturients at increased risk for complications from general anaesthesia, and alert the anaesthetist when identified. Hence, it is important for institutions that provide obstetric anaesthesia to have appropriate ‘unanticipated difficult airway’ and ‘failed intubation’ protocols. One could potentially decrease maternal morbidity and mortality associated with the provision of general anaesthesia for caesarean section by calling for organised drills and mock airway codes specific for the obstetric population to enable caregivers to function as a team.

The issue of difficult airway during general anaesthesia has largely been circumvented by the increasing use of regional anaesthesia. Even though trainees may be very proficient in the conduct of spinal or epidural anaesthesia, they are usually not as familiar with handling a real-life difficult airway for caesarean section. Many anaesthetists may encounter a difficult airway for the first time when called upon to anaesthetise such a patient in an emergency. The challenge is in the difficulty to ramp up one’s capability to handle these cases when the exposure to general anaesthesia is limited in the normal situation. There is a constant struggle to maintain safety of general anaesthesia with the lack of experienced anaesthetists to undertake the task, especially in remote areas and developing countries where the overall numbers of trained anaesthetists are few, and regional techniques are widely used as it is deemed safer and cheaper for the parturient. The safety of anaesthesia will certainly be enhanced with the more widespread availability of critical monitoring tools, such as pulse oximetry, and the training of their usage in developing countries.

Indeed, there are some positive signs on the horizon. For example, the recent ASA closed claims analysis found that there were no fatalities due to failed intubation since 1999. This state of affairs could be attributed to an increased awareness of potential airway catastrophes at the time of general anaesthesia, more frequent usage of regional anaesthesia, improvements in the difficult airway algorithm and of the use of the laryngeal mask airway (LMA) as a ‘rescue’ airway in the event of a failed intubation. The usefulness of the LMA in this situation is generally very well accepted and has been incorporated into the ASA difficult airway protocol. The LMA has also been used selectively for elective caesarean section even though there is no evidence to support its routine use at this point in time. Although the LMA is easy to insert, there are potential issues with its use in obstetric anaesthesia, principally related to the potential risk of regurgitation and aspiration of gastric content. The LMA ProSeal™, which has a port that allows drainage of gastric contents apart from affording a better oropharyngeal seal, has been shown to be effective as a temporary airway for post-partum patients. There have also been several reports of the successful use of the ProSeal™ as the rescue airway for failed intubation during general anaesthesia for caesarean section, even though there are no reports of properly performed randomised controlled trials to examine its safety in this context. Nevertheless, it is important to include tools such as the LMA and ProSeal™ (among others such as intubating fibre-optic bronchoscope, gum elastic bougie and cricothyroidotomy set) in the ‘difficult airway’ trolley, in the event of unexpected difficult intubation. Novel video-laryngoscopic devices have also been shown to either shorten the time to tracheal intubation or improve the quality of oxygenation when compared with the traditional direct laryngoscope, although that there is a significant learning curve involved and experience is limited in maternity patients.

Moreover, the incidence of maternal mortality due to aspiration during delivery is now rare; this could be attributable to a heightened awareness of the increased risk, enforcement of fasting guidelines, institution of aspiration prophylaxis and the increasing trend for use of regional anaesthesia for caesarean section delivery. Even though there has been a drastic reduction in maternal deaths from aspiration over the past few decades (from 1:42000 births in the USA in the 1950s, to only two closed claims in the ASA database since the 1990s), it is still a potential risk that the obstetric anaesthetist should not dismiss.

Central neuraxial anaesthesia in the pregnant patient