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Correspondence - Failed intubation in a parturient with spina bifida
International Journal of Obstetric Anesthesia (2000) 9, 290–296 © 2000 Harcourt Publishers Ltd
CORRESPONDENCE
The need for operation was not so urgent, because the life of neither mother nor baby was in immediate danger. It was surprising that the authors were trying to justify the use of LMA by stating that the competence of the upper oesophageal sphincter is maintained during LMA anaesthesia and the risk of aspiration was not great even without cricoid pressure. But the fact is that it is lower oesophageal sphincter (gastroesophageal) and the barrier pressure between the stomach and oesophagus that determine the risks of regurgitation.4 We believe that the risk of regurgitation and aspiration was significant in this case because of positive pressure ventilation in a partially obstructed airway. This may be due to gas entry into the stomach and the partially inflated stomach predisposing towards regurgitation and aspiration.4,5 Thus the described management of this case does not fit with standard algorithms.5,6 N. G. Mandal, J. Wilson, N. J. Hollis Department of Anaesthetics, Dorset County Hospital, Williams Avenue, Dorchester, UK
Failed intubation in a parturient with spina bifida We were interested to read the case report entitled ‘Failed intubation in a parturient with spina bifida’ by Anderson et al.1 The authors should be congratulated for keeping the patient alive without any obvious complication. However, we would like to comment on aspects of clinical management and on some points mentioned in their text. While we certainly agree with the complexity of the situation, we can not agree with the sequence of events that took place. We were surprised to note that a Mallampati class I airway had converted into class III over a span of 10 days. It would be interesting to note her Mallampati class now while she is not pregnant. As the authors anticipated a difficult intubation after their second preanaesthetic assessment and neither maternal nor fetal life was at risk, then an alternative technique to standard rapid sequence induction such as awake fibreoptic intubation could have been tried. We think it would have been a safer option. It is very surprising that only one attempt to intubate was made. It is not clear from the article who attempted it. If it was the anaesthetic registrar then it makes sense for a trial by the consultant after improvement in oxygen saturation. We see no reason why a McCoy laryngoscope blade was not used as the first choice in view of anticipated difficulty. This blade is normally available in every maternity unit’s anaesthetic trolley in the United Kingdom. It could convert Cormack & Lehane grade III laryngoscopy to grade II and thus an endotracheal tube could have been passed more easily with or without a bougie.2 The authors claimed that regional anaesthesia was contraindicated. In this particular situation we believe that regional anaesthesia would have been a safer option than continuing general anaesthesia using laryngeal mask airway (LMA™) with an unprotected airway risking pulmonary aspiration of gastric contents. That the patient did not have any obvious sign of regurgitation is fortunate when positive pressure ventilation had been used for a difficult and partially obstructed airway. Although the patient did not eat anything for 8 h before anaesthesia, it was not unlikely that some solid food still remained in the stomach. On ultrasound examination of the stomach, Carp et al. detected solid food in 41% of pregnant patients even though they had eaten 8–24 h before the examination.3
Editor’s Note The lower oesophageal sphincter prevents reflux, while the upper prevents regurgitation. FR REFERENCES 1. 2. 3. 4.
5. 6.
Anderson K J, Quinlan M J, Popat M, Russell R. Failed intubation in a parturient with spina bifida. International Journal of Obstetric Anesthesia 2000; 9: 64–68. Chisholm D G, Calder I. Experience with MacCoy laryngoscope in difficult laryngoscopy. Anaesthesia 1997; 52: 906–908. Carp H, Jayaram A, Stoll M. Ultrasound examination of the stomach contents of parturients. Anesth Analg 1992; 74: 683–685. Gibbs C P, Modell J H. Pulmonary aspiration of gastric contents: pathophysiology, prevention, and management. In: Miller RD ed. Anesthesia, 4th edn. New York, Churchill Livingstone, 1994: pp 1437–1464. Shinder S M, Levinson G. Anesthesia for Obstetrics. In: Miller R D ed. Anesthesia, 4th edn. New York, Churchill Livingstone, 1994: pp 2031–2076. Benumof J L. Laryngeal mask airway and the ASA difficult airway algorithm. Anesthesiology 1996; 84: 686–699.
In reply We thank Drs Mandal, Wilson and Hollis for their interest in our case report. Hindsight is a wonderful 290
CORRESPONDENCE
The need for operation was not so urgent, because the life of neither mother nor baby was in immediate danger. It was surprising that the authors were trying to justify the use of LMA by stating that the competence of the upper oesophageal sphincter is maintained during LMA anaesthesia and the risk of aspiration was not great even without cricoid pressure. But the fact is that it is lower oesophageal sphincter (gastroesophageal) and the barrier pressure between the stomach and oesophagus that determine the risks of regurgitation.4 We believe that the risk of regurgitation and aspiration was significant in this case because of positive pressure ventilation in a partially obstructed airway. This may be due to gas entry into the stomach and the partially inflated stomach predisposing towards regurgitation and aspiration.4,5 Thus the described management of this case does not fit with standard algorithms.5,6 N. G. Mandal, J. Wilson, N. J. Hollis Department of Anaesthetics, Dorset County Hospital, Williams Avenue, Dorchester, UK
Failed intubation in a parturient with spina bifida We were interested to read the case report entitled ‘Failed intubation in a parturient with spina bifida’ by Anderson et al.1 The authors should be congratulated for keeping the patient alive without any obvious complication. However, we would like to comment on aspects of clinical management and on some points mentioned in their text. While we certainly agree with the complexity of the situation, we can not agree with the sequence of events that took place. We were surprised to note that a Mallampati class I airway had converted into class III over a span of 10 days. It would be interesting to note her Mallampati class now while she is not pregnant. As the authors anticipated a difficult intubation after their second preanaesthetic assessment and neither maternal nor fetal life was at risk, then an alternative technique to standard rapid sequence induction such as awake fibreoptic intubation could have been tried. We think it would have been a safer option. It is very surprising that only one attempt to intubate was made. It is not clear from the article who attempted it. If it was the anaesthetic registrar then it makes sense for a trial by the consultant after improvement in oxygen saturation. We see no reason why a McCoy laryngoscope blade was not used as the first choice in view of anticipated difficulty. This blade is normally available in every maternity unit’s anaesthetic trolley in the United Kingdom. It could convert Cormack & Lehane grade III laryngoscopy to grade II and thus an endotracheal tube could have been passed more easily with or without a bougie.2 The authors claimed that regional anaesthesia was contraindicated. In this particular situation we believe that regional anaesthesia would have been a safer option than continuing general anaesthesia using laryngeal mask airway (LMA™) with an unprotected airway risking pulmonary aspiration of gastric contents. That the patient did not have any obvious sign of regurgitation is fortunate when positive pressure ventilation had been used for a difficult and partially obstructed airway. Although the patient did not eat anything for 8 h before anaesthesia, it was not unlikely that some solid food still remained in the stomach. On ultrasound examination of the stomach, Carp et al. detected solid food in 41% of pregnant patients even though they had eaten 8–24 h before the examination.3
Editor’s Note The lower oesophageal sphincter prevents reflux, while the upper prevents regurgitation. FR REFERENCES 1. 2. 3. 4.
5. 6.
Anderson K J, Quinlan M J, Popat M, Russell R. Failed intubation in a parturient with spina bifida. International Journal of Obstetric Anesthesia 2000; 9: 64–68. Chisholm D G, Calder I. Experience with MacCoy laryngoscope in difficult laryngoscopy. Anaesthesia 1997; 52: 906–908. Carp H, Jayaram A, Stoll M. Ultrasound examination of the stomach contents of parturients. Anesth Analg 1992; 74: 683–685. Gibbs C P, Modell J H. Pulmonary aspiration of gastric contents: pathophysiology, prevention, and management. In: Miller RD ed. Anesthesia, 4th edn. New York, Churchill Livingstone, 1994: pp 1437–1464. Shinder S M, Levinson G. Anesthesia for Obstetrics. In: Miller R D ed. Anesthesia, 4th edn. New York, Churchill Livingstone, 1994: pp 2031–2076. Benumof J L. Laryngeal mask airway and the ASA difficult airway algorithm. Anesthesiology 1996; 84: 686–699.
In reply We thank Drs Mandal, Wilson and Hollis for their interest in our case report. Hindsight is a wonderful 290