Frederic J. Gerges

Preoperative caudal block prevents emergence agitation in children following sevoflurane anesthesia

Background:  The frequency of emergence agitation in children is increased following sevoflurane anesthesia. However, controversies still exist concerning the exact etiology of this postanesthetic problem. Although this phenomenon is present with adequate pain relief or even following pain‐free procedures, pain is still regarded as a major contributing factor.

Prophylactic methylene blue in a patient with congenital methemoglobinemia.

PurposeTo report the beneficial effect of prophylactic methylene blue administration before induction of anesthesia in a patient with congenital methemoglobinemia.Clinical featuresA 26-yr-old male patient known to have congenital methemoglobinemia was scheduled forturbinectomy under general anesthesia. The patient was clinically cyanotic with a pulse oximetry of 91 %. Arterial blood gas analysis showed a partial pressure of oxygen (PaO2) of 81.3 mmHg associated with a fractional oxyhemoglobin of 80.7%, and a methemoglobin fraction of 0.159. Preoperativeiv administration of 1 mg·kg-1 of methylene blue resulted, within five minutes, in a decrease of methemoglobin fraction down to 0.05 associated with an increase of the fractional oxyhemoglobin saturation up to 94.7%. After two hours, the methemoglobin fraction decreased to 0.01 and the fractional oxyhemoglobin concentration increased to 97.7%. Induction of anesthesia as well as intraoperative and postoperative course were uneventful without any episode of hypoxemia. Postoperatively, the methemoglobin fractions remained low for 24 hr, to be followed by a gradual increase up to 0.02 on the second day to reach 0.094 on the fifth day.ConclusionThe prophylactic preoperative methylene blue administration in a patient with congenital methemoglobinemia significantly decreased the methemoglobin level and increased the fractional oxygen saturation with a consequent increase of the safety margin against perioperative hypoxemia.RésuméObjectifSignaler l’effet bénéfique de l’administration prophylactique de bleu de méthylène avant l’induction de l’anesthésie chez un patient atteint de méthémoglobinémie congénitale.Éléments cliniquesUn homme de 26 ans atteint de méthémoglobinémie congénitale devait subir une turbinectomie sous anesthésie générale. Le patient était cyanosé et présentait une sphygmo- oxymétrie de 91 %. L’analyse des gaz artériels a montré une pression partielle d’oxygène (PaO2) de 81,3 mmHg associée à une oxyhémo- globine fractionnelle de 80,7 % et à une fraction de méthémoglobine de 0,159. L’administration iv préopératoire de 1 mg·kg-1 de bleu de méthylène a donné, en moins de cinq minutes, une baisse de la frac- tion de méthémoglobine jusqu’à 0,05, et une hausse de la saturation d’oxyhémoglobine fractionnelle jusqu’à 94,7 %. Après deux heures, la fraction de méthémoglobine a baissé à 0,01 et la concentration d’oxy- hémoglobine fractionnelle a augmenté à 97,7 %. L’induction de l’anesthésie et l’évolution peropératoire et postopératoire ont été sans incident et sans épisode d’hypoxémie. Après l’opération, les fractions de méthémoglobine sont demeurées basses pendant 24 h et ont été suivies d’une hausse graduelle jusqu’à 0,02 le deuxième jour et 0,094 le cinquième jour.Conclusion : L’administrationprophylactique préopératoire de bleu de méthylène chez un patient atteint de méthémoglobinémie con-génitale a significativement réduit le niveau de méthémoglobine et augmenté la saturation en oxygène fractionnée, ce qui a augmenté la marge de sécurité contre l’hypoxémie périopératoire.PURPOSE To report the beneficial effect of prophylactic methylene blue administration before induction of anesthesia in a patient with congenital methemoglobinemia. CLINICAL FEATURES A 26-yr-old male patient known to have congenital methemoglobinemia was scheduled for turbinectomy under general anesthesia. The patient was clinically cyanotic with a pulse oximetry of 91%. Arterial blood gas analysis showed a partial pressure of oxygen (PaO(2)) of 81.3 mmHg associated with a fractional oxyhemoglobin of 80.7%, and a methemoglobin fraction of 0.159. Preoperative iv administration of 1 mg.kg(-1) of methylene blue resulted, within five minutes, in a decrease of methemoglobin fraction down to 0.05 associated with an increase of the fractional oxyhemoglobin saturation up to 94.7%. After two hours, the methemoglobin fraction decreased to 0.01 and the fractional oxyhemoglobin concentration increased to 97.7%. Induction of anesthesia as well as intraoperative and postoperative course were uneventful without any episode of hypoxemia. Postoperatively, the methemoglobin fractions remained low for 24 hr, to be followed by a gradual increase up to 0.02 on the second day to reach 0.094 on the fifth day. CONCLUSION The prophylactic preoperative methylene blue administration in a patient with congenital methemoglobinemia significantly decreased the methemoglobin level and increased the fractional oxygen saturation with a consequent increase of the safety margin against perioperative hypoxemia.

Resistance to cisatracurium in a patient with MELAS syndrome

There are conflicting reports on the response of mitochondrial myopathy patients to the neuromuscular blocking drugs, showing either normal response or marked sensitivity. We present a patient with MELAS syndrome who underwent Nissen fundoplication and gastrojejunostomy. Marked resistance to the nondepolarizing muscle relaxant, cisatracurium was observed. The anesthesia management, as well as the various causes of resistance to cisatracurium in this patient are discussed.