Anaesthesia for emergency caesarean section using the brain laryngeal airway

Equipment to manage a difficult airway during anaesthesia

Airway complications are a leading cause of morbidity and mortality in anaesthesia. Effective management of a difficult airway requires the timely availability of suitable airway equipment. The Australian and New Zealand College of Anaesthetists has recently developed guidelines for the minimum set of equipment needed for the effective management of an unexpected difficult airway (TG4 [2010] www.anzca.edu.au/resources/professionaldocuments). TG4 [2010] is based on expert consensus, underpinned by wide consultation and an extensive review of the available evidence, which is summarised in a Background Paper (TG4 BP [2010] www.anzca.edu.au/ resources/professional-documents). TG4 [2010] will be reviewed at the end of one year and thereafter every five years or more frequently if necessary. The current paper is reproduced directly from the Background Paper (TG4 BP [2010]).

Maternal morbidity, mortality, and risk assessment

Maternal deaths in developed countries continue to decline and are rare. Maternal mortality statistics are essentially similar in the United States and United Kingdom. However, the situation is completely different in developing countries, where maternal mortality exceeds 0.5 million every year. This article not only assesses morbidity risks in some of the leading causes of maternal death but also highlights strategies to minimize the risks and to prevent maternal morbidity and mortality.

Carotid artery puncture, airway obstruction and the laryngeal mask airway in a preeclamptic patient

We report a case of a preeclamptic patient with a difficult airway in whom attempted central venous cannulation led to inadvertent carotid artery puncture and dilatation causing immediate life threatening upper airway obstruction. The use of the laryngeal mask airway was life-saving on two occasions when other techniques of airway management had failed. We discuss the series of events that led to this critical incident and suggest areas in which management might have been improved.

Failed tracheal intubation in obstetrics: no more frequent but still managed badly

In the South-West Thames region of the United Kingdom, during a 5-year period from 1999 to 2003, there were 20 failed tracheal intubations occurring in 4768 obstetric general anaesthetics (incidence 1 : 238). In half of the 16 cases for which the patient's notes could be examined there was a failure to follow an accepted protocol for failed tracheal intubation.

Airway problems in pregnancy

Obstetric anesthesia is considered to be a difficult, high-risk practice that exposes the anesthesiologist to increased medicolegal liability. Anesthetic management of parturient patients is a challenge, as it involves simultaneous care of two lives. The anesthesia practitioner has a duty to provide safe anesthetic care, including effective airway management when providing regional or general anesthesia. The potential need to manipulate the airway is perhaps the leading cause of concern among obstetric anesthesiologists.

Difficult Airway Society guidelines for management of the unanticipated difficult intubation

Problems with tracheal intubation are infrequent but are the most common cause of anaesthetic death or brain damage. The clinical situation is not always managed well. The Difficult Airway Society (DAS) has developed guidelines for management of the unanticipated difficult tracheal intubation in the non-obstetric adult patient without upper airway obstruction. These guidelines have been developed by consensus and are based on evidence and experience. We have produced flow-charts for three scenarios: routine induction; rapid sequence induction; and failed intubation, increasing hypoxaemia and difficult ventilation in the paralysed, anaesthetised patient. The flow-charts are simple, clear and definitive. They can be fully implemented only when the necessary equipment and training are available. The guidelines received overwhelming support from the membership of the DAS.

DISCLAIMER

It is not intended that these guidelines should constitute a minimum standard of practice, nor are they to be regarded as a substitute for good clinical judgement.

Failed obstetric tracheal intubation and postoperative respiratory support with the ProSeal laryngeal mask airway

The ProSeal laryngeal mask airway (ProSeal LMA) provides a better seal and probably better airway protection than the classic laryngeal mask airway (classic LMA). We report the use of the ProSeal LMA in a 26-yr-old female with HELLP syndrome for failed obstetric intubation and postoperative respiratory support. Both laryngoscope-guided tracheal intubation and face mask ventilation failed, but a size 4 ProSeal LMA was easily inserted and high tidal volumes obtained. A gastric tube was inserted through the ProSeal LMA drain tube and 300 mL of clear fluid was removed from the stomach. There were no hemodynamic changes during ProSeal LMA insertion. Postoperatively, the patient was transferred to the intensive care unit, where she was ventilated via the ProSeal LMA for 8 h until the platelet count had increased and she was hemodynamically stable. Weaning and ProSeal LMA removal were uneventful. There is anecdotal evidence supporting the use of the LMA devices for failed obstetric intubation (19 cases) and for postoperative respiratory support (8 cases). In principle, the ProSeal LMA may offer some advantages over the classic LMA in both these situations.

IMPLICATIONS

We report the successful use of the ProSeal laryngeal mask airway for failed obstetric intubation and postoperative respiratory support in a patient with HELLP syndrome.

Airway problems and new solutions for the obstetric patient

Anesthesia-related complications are the sixth leading cause of pregnancy-related maternal mortality in the United States. Difficult or failed intubation following induction of general anesthesia for cesarean delivery remains the major contributory factor to anesthesia-related maternal complications. Although the use of general anesthesia has been declining in obstetric patients, it may still be required in selected cases. Because difficult intubation in obstetric anesthesia practice is frequently unexpected, careful and timely preanesthetic evaluation of all parturients should identify the majority of patients with difficult airway and avoid unexpected difficult airway management.

Failed tracheal intubation in obstetrics: a 6-year review in a UK region

In the South Thames (West) region of the United Kingdom, during a 6-year period from 1993 to 1998, there was a significant increase in the Caesarean section rate accompanied by a significant decrease in the use of general anaesthesia for operative delivery. During this time, there were 36 failed tracheal intubations occurring in 8970 obstetric general anaesthetics (incidence 1/249). There was no significant difference in the incidence of failed tracheal intubation in each of the six years. In 24 of the 26 cases for which the patients' notes could be examined, there was either no recording of preoperative assessment, a failure to follow an accepted protocol for failed tracheal intubation, or no follow-up.

The laryngeal mask airway reliably provides rescue ventilation in cases of unanticipated difficult tracheal intubation along with difficult mask ventilation

In 1995, our department of anesthesiology established an airway team to assist in treating unanticipated difficult endotracheal intubations and an airway quality improvement (QI) form to document the use of emergency airway techniques in airway crises (laryngeal mask airway [LMA], flexible fiberoptic bronchoscopy, retrograde intubation [RI], transtracheal jet ventilation [TTJV], and cricothyrotomy). Over a 2-yr period, team members and staff anesthesiologists completed airway QI forms to document the smallest peripheral SpO2 during an airway crisis, the number of direct laryngoscopies (DL) performed before using an emergency airway technique, and the emergency airway technique that succeeded in rescue ventilation. Team members agreed to use the LMA as the first emergency airway technique to treat the difficult ventilation/difficult intubation scenario. A SpO2 value < or =90% during mask ventilation defined difficult ventilation. Inability to perform tracheal intubation by DL defined difficult intubation. An increase in the SpO2 value >90% defined rescue ventilation. Review of airway QI forms from October 1, 1995 until October 1, 1997 revealed 25 cases of difficult ventilation/difficult intubation. Before airway rescue, the median SpO2 was 80% (range 50%-90%), and there were four median attempts at DL (range one to nine). The LMA had a success rate of 94% (95% confidence interval [CI] 77-100). Flexible fiberoptic bronchoscopy, TTJV, RI, and surgical cricothyrotomy had success rates of 50% (95% CI 0-100), 33% (95% CI 0-100), 100% (95% CI 37-100), and 100% (95% CI 37-100), respectively. LMA insertion as the first alternative airway technique was useful in dealing with unanticipated instances of simultaneous difficulty with mask ventilation and tracheal intubation.

IMPLICATIONS

Twenty-five cases of simultaneous difficulty with mask ventilation and tracheal intubation occurred after the induction of general anesthesia during the study period. The laryngeal mask was used in 17 cases, and it provided rescue ventilation without complication in 94% of these cases (95% confidence interval 77-100).

The unanticipated difficult airway with recommendations for management

PURPOSE

To review the current literature and generate recommendations on the role of newer technology in the management of the unanticipated difficult airway.

METHODS

A literature search using key words and filters of English language and English abstracted publications from 1990-96 contained in the Medline, Current Contents and Biological Abstracts databases was carried out. The literature was reviewed and condensed and a series of evidence-based recommendations were evolved.

CONCLUSIONS

The unanticipated difficult airway occurs with a low but consistent incidence in anaesthesia practice. Difficult direct laryngoscopy occurs in 1.5-8.5% of general anaesthetics and difficult intubation occurs with a similar incidence. Failed intubation occurs in 0.13-0.3% general anaesthetics. Current techniques for predicting difficulty with laryngoscopy and intubation are sensitive, non-specific and have a low positive predictive value. Assessment techniques which utilize multiple characteristics to derive a risk factor tend to be more accurate predictors. Devices such as the laryngeal mask, lighted stylet and rigid fibreoptic laryngoscopes, in the setting of unanticipated difficult airway, are effective in establishing a patient airway, may reduce morbidity and are occasionally lifesaving. Evidence supports their use in this setting as either alternatives to facemask and bag ventilation, when it is inadequate to support oxygenation, or to the direct laryngoscope, when tracheal intubation has failed. Specifically, the laryngeal mask and Combitube have proved to be effective in establishing and maintaining a patent airway in "cannot ventilate" situations. The lighted stylet and Bullard (rigid) fibreoptic scope are effective in many instances where the direct laryngoscope has failed to facilitate tracheal intubation. The data also support integration of these devices into strategies to manage difficult airway as the new standard of care. Training programmes should ensure graduate physicians are trained in the use of these alternatives. Continuing medical education courses should allow physicians in practice the opportunity to train with these alternative devices.

The laryngeal mask airway in obstetrical anaesthesia

The laryngeal mask airway (LMA) has been used extensively to provide a safe airway in spontaneously breathing patients who are not at risk from aspiration of gastric contents. The role of the LMA in the event of a failed intubation in an obstetrical patient, and its place in a failed intubation drill remains unclear. Two hundred and fifty consultant obstetric anaesthetists in the United Kingdom were asked to complete an anonymous questionnaire regarding their views about using the laryngeal mask airway (LMA) in obstetrical anaesthesia. The LMA was available in 91.4% of obstetric units. Seventy-two per cent of anaesthetists were in favour of using the LMA to maintain oxygenation when tracheal intubation had failed and ventilation using a face mask was inadequate. Twenty-four respondents had had personal experience with the LMA in obstetrical anaesthesia, eight of whom stated that the LMA had proved to be a lifesaver. We believe that the LMA has a role in obstetrical anaesthesia when tracheal intubation has failed and ventilation using a face mask proves to be impossible, and it should be inserted before attempting cricothyroidectomy.

Anaesthesia and mucopolysaccharidoses. A review of airway problems in children

The airway problems encountered during anaesthesia in all children with mucopolysaccharidoses presenting for a surgical procedure from 1988 to September 1991 are reviewed. Thirty-four patients underwent 89 anaesthetics for 110 procedures. The results reveal a high incidence of airway problems. The overall incidence of difficult intubation was 25% and failed intubation 8%. In those children with Hurler's syndrome, the difficult intubation incidence was 54% and failed intubation incidence 23%. Other potential anaesthetic problems such as cardiac anomalies and obstructive sleep apnoea are also reviewed.

The laryngeal mask airway: its features, effects and role

The laryngeal mask airway was designed as a new concept in airway management and has been gaining a firm position in anaesthetic practice. Numerous articles and letters about the device have been published in the last decade, but few large controlled trials have been performed. Despite widespread use, the definitive role of the laryngeal mask has yet to be established. In some situations, such as after failed tracheal intubation or in anaesthesia for patients undergoing laparoscopic or oral surgery, its use is controversial. There are a number of unresolved issues, for example the effect of the laryngeal mask on regurgitation and whether or not cricoid pressure prevents placement of the mask. We review the techniques of insertion, details of misplacement, and complications associated with the use of the laryngeal mask. We discuss the features and physiological effects of the device, including the changes in intra-cuff pressure during anaesthesia and effects on blood pressure, heart rate and intra-ocular pressure. We then attempt to clarify the role of the laryngeal mask in airway management during anaesthesia, based on the current knowledge, by discussing the advantages and disadvantages as well as the indications and contraindications of its use. Lastly we describe the use of the laryngeal mask in circumstances other than airway maintenance during anaesthesia: fibreoptic bronchoscopy, tracheal intubation through the mask and its use in cardiopulmonary resuscitation.

Does the laryngeal mask airway compromise cricoid pressure?

The laryngeal mask airway was inserted in 10 cadavers. At postmortem the chest was opened and an infusion set primed with a dilute barium solution was inserted into the oesophagus and ligated in place. A cricoid force of 43 N was then applied and the infusion set was positioned so that when the clamp was opened it generated a pressure of 7.8 kPa within the oesophagus. The cricoid pressure was able to stop the flow of fluid into the oesophagus. This demonstrates that cricoid pressure is effective in preventing reflux at intragastric pressures which are encountered clinically and the presence of the laryngeal mask airway does not compromise this.

Management of a suspected and unsuspected difficult laryngoscopy with the laryngeal mask airway

The laryngeal mask airway (LMA) is a new development in airway control. Presented here are two cases of difficult airway management--one anticipated, the other not anticipated--during which the LMA was used effectively.

[Difficult intubation managed by laryngeal mask and fibroscopy]

A case is reported of a patient due to undergo a combined kidney and pancreas transplant who proved to be difficult to intubate. This diabetic hypertensive 35-year-old male patient also had ankylosing spondylitis. Mouth opening was normal (more than fingers' breadth), the chin-sternum distance was 4 cm on full cervical flexion, and cervical extension was only slightly impaired. The Mallampati score was 1. Anaesthesia was induced with thiopentone, fentanyl and 6 mg of pancuronium. Mask ventilation was quite satisfactory. However, on laryngoscopy, the vocal cords could not be seen. Several attempts to carry out endotracheal intubation, including with a stylet, failed. A laryngeal mask (LM) was therefore applied to ventilate the patient correctly. It was not possible to pass a small endotracheal tube (6 mm diameter) through the LM tube, probably because of a small malposition of this latter. A paediatric fibroscope, passed through the LM tube, served as guide for the endotracheal tube. The mask was not removed, although its cushion was slightly deflated, so as not to extubate the patient. The benefits and usefulness of a laryngeal mask in predictable and unpredictable cases of difficult intubation are discussed.

The use of a laryngeal mask airway in spontaneously breathing patients

The Laryngeal Mask Airway (LMA) is a new type of oropharyngeal airway that provides an alternative to endotracheal intubation and standard mask anaesthesia in certain cases. Once the patient is adequately anaesthetised, it can be inserted blindly, without recourse to laryngoscopy or muscle relaxants. Anaesthetists of all grades, given minimum instruction, were able to provide a clinically satisfactory airway in 49 out of 50 spontaneously breathing, anaesthetised patients. The advantages over standard mask anaesthesia are: better airway control, minimal leakage of anaesthetic gases, secure airway during transport to the recovery ward, and it frees the anaesthetist's hands, as no mandibular support is needed. Postoperative problems were minimal and 97.6% of our patients said that they would prefer a similar anaesthetic in future. LMA does not guarantee against the risk of aspiration and it is not recommended for use in patients who may have a full stomach.

The Brain laryngeal mask airway. An alternative to emergency tracheal intubation

The laryngeal mask airway was used to resuscitate a patient in whom direct and fibreoptic laryngoscopy were impossible because of cervical pathology and pulmonary oedema. The laryngeal mask airway may be an alternative to tracheal intubation in emergency resuscitation.

[The laryngeal mask]

A new type of airway has been widely used for two years, throughout hospitals in the United Kingdom. Designed and created since 1983 by Dr AIJ Brain, the Laryngeal Mask Airway (LMA) is a compromise between the endotracheal tube and the face-mask. Blindly inserted in an anaesthetized patient, without either a laryngoscope or neuromuscular blockade, it provides a good airway in almost all cases. It is often able to offer an effective alternative to difficult intubation. The LMA can be used with either spontaneous or positive pressure ventilation. Because it doesn't provide a reliable protection of the airway from aspiration, it should never be used in the patient with a full stomach. The spontaneously breathing patient, undergoing elective surgery for 15 to 60 minutes, in supine position, who would ordinarily be managed with a face-mask is the more likely candidate for the LMA. But, longer procedures, in lateral or prone position, with controlled ventilation can usually be carried out using the Brain's device. More effective and less demanding than the facial-mask, much less hurtful than the endotracheal tube, the Laryngeal Mask is potentially an important and valuable addition to anaesthetic care.