Severity and duration of hypoxemia during outpatient endoscopy in obese patients: a retrospective cohort study.

PURPOSE: We sought to quantify the severity and duration of hypoxemic events in morbidly obese patients during outpatient endoscopy procedures performed under deep sedation. METHODS: This was a retrospective cohort study using intraprocedural pulse oximetry readings from 11,595 American Society of Anesthesiologists physical status score I-III adult patients who underwent deep sedation for elective endoscopy at free standing ambulatory centres between June 2015 and June 2016. Unadjusted and risk-adjusted logistic regression analyses explored the relationship between increasing categories of body mass index (BMI) and intraoperative hypoxemia, severe hypoxemia, and prolonged hypoxemia. RESULTS: Hypoxemia occurred in 600 (13%) patients with normal BMI, 314 (18%) with class I obesity, 159 (27%) with class II obesity, and 24 (19%) with class III obesity. Adjusted odds ratio (AOR) for any occurrence of intraoperative hypoxemia increased from 1.61 (95% confidence interval [CI], 1.35 to 1.90; P < 0.001) in the class I obesity group to 2.61 (95% CI, 2.05 to 3.30; P < 0.001) in patients with class II obesity, when compared with patients with normal BMI. Adjusted odds ratio of severe hypoxemia were significant in the class I obesity group (AOR, 1.47; 95% CI, 1.13 to 1.89; P = 0.003), and the class II obesity group (AOR, 2.59; 95% CI, 1.86 to 3.57; P < 0.001). Adjusted odds ratio of prolonged hypoxemia increased with each category of BMI from 1.97 (95% CI, 1.08 to 3.69) in the overweight group to 9.20 (95% CI, 4.74 to 18.03) in patients with class III obesity. CONCLUSIONS: The incidence of severe hypoxemia increased nearly six-fold in obese patients and 8.5-fold in class III obese patients when compared with those of normal BMI. Intravenous fentanyl was associated with intraoperative hypoxemia independent of BMI. Patients who represent the highest risk for hypoxia should be stratified to procedure locations with adequate resources for the safest care.

RéSUMé: OBJECTIF: Nous avons tenté de quantifier la gravité et la durée des complications hypoxémiques chez les patients obèses morbides pendant les interventions endoscopiques ambulatoires réalisées sous sédation profonde. MéTHODE: Nous avons réalisé une étude de cohorte rétrospective en nous fondant sur les relevés d'oxymétrie de pouls intra-procéduraux de 11 595 patients adultes de statut physique ASA (American Society of Anesthesiologists) I-III ayant subi une sédation profonde pour une endoscopie non urgente dans des centres ambulatoires indépendants entre juin 2015 et juin 2016. Les analyses de régression logistique non ajustées et ajustées en fonction du risque ont examiné la relation entre des catégories croissantes d'indice de masse corporelle (IMC) et l'hypoxémie, l'hypoxémie sévère et l'hypoxémie prolongée peropératoires. RéSULTATS: L'hypoxémie a touché 600 (13 %) patients ayant un IMC normal, 314 (18 %) patients souffrant d'une obésité de classe I, 159 (27 %) patients avec une obésité de classe II, et 24 (19 %) patients souffrant d'obésité de classe III. Le rapport de cotes ajusté (RCA) pour tout épisode d'hypoxémie peropératoire a augmenté de 1,61 (intervalle de confiance [IC] 95 %, 1,35 à 1,90; P < 0,001) dans le groupe obésité de classe I à 2,61 (IC 95 %, 2,05 à 3,30; P < 0,001) chez les patients présentant une obésité de classe II, par rapport aux patients avec un IMC normal. Les rapports de cotes ajustés pour l'hypoxémie sévère étaient significatifs dans le groupe de patients obèses de classe I (RCA, 1,47; IC 95 %, 1,13 à 1,89; P = 0,003) et dans le groupe de patients obèses de classe II (RCA, 2,59; IC 95 %, 1,86 à 3,57; P < 0,001). Les rapports de cotes ajustés pour l'hypoxémie prolongée ont augmenté avec chaque catégorie d'IMC, passant de 1,97 (IC 95 %, 1,08 à 3,69) dans le groupe en surcharge pondérale à 9,20 (IC 95 %, 4,74 à 18,03) chez les patients atteints d'obésité de classe III. CONCLUSION: L'incidence d'hypoxémie sévère a augmenté de près de six fois chez les patients obèses et de 8,5 fois chez les patients obèses de classe III par rapport aux patients ayant un IMC normal. L'administration intraveineuse de fentanyl était associée à une hypoxémie peropératoire indépendante de l'IMC. Les patients qui présentent le risque le plus élevé d'hypoxie devraient être stratifiés à être pris en charge dans des établissements disposant des ressources nécessaires pour offrir les soins les plus sécuritaires possibles.

General anesthesia in a patient with citrullinemia using Precedex as an adjunct to prevent delayed emergence.

Citrullinemia type I is a rare autosomal recessive genetic condition that causes reduced activity of the enzyme, argininosuccinate synthase, which is needed for proper urea metabolism. The end result is hyperammonemia which can cause life-threatening neurologic symptoms and global developmental delay. Previous case reports of the anesthetic management of patients with citrullinemia describe delayed recovery possibly related to elevated ammonia levels postoperatively or choice of intraoperative anesthetics which have included narcotics. In this case report, we present the anesthetic management of a 16-year-old adolescent girl with citrullinemia type I undergoing a vagus nerve stimulator revision. We used the α-2-adrenergic agonist, dexmedetomidine, as an adjunct to avoid narcotics to prevent delayed emergence. She was admitted for hydration the night before the procedure and had a baseline ammonia level of 33 µmol/L (reference, 9-33 µmol/L). Anesthetic maintenance consisted of 2% sevoflurane, dexmedetomidine 0.5 µg/kg per hour, and intravenous acetaminophen given toward the conclusion of the surgery. The patient awoke immediately at the end of the procedure and was extubated in the operating room. Postprocedure, her ammonia level was less than 9 µmol/L. She appeared to be free of pain, was tolerating gastric tube feeds postprocedure, and was discharged to home on the day of surgery. Effective management of ammonia levels in this patient using preoperative hydration and dexmedetomidine as an adjunct to general anesthesia may have helped to prevent delayed emergence.

A prospective, randomized, placebo-controlled study evaluating the efficacy of dexmedetomidine for sedation during vascular procedures.

OBJECTIVE: To examine the efficacy of dexmedetomidine (DEX) as a primary sedative during vascular procedures performed under monitored anesthesia care (MAC). A total of 55 patients were randomized in a 2:2:1 ratio to receive either DEX 1.0 microg/kg load or DEX 0.5 microg/kg load versus midazolam (MDZ) boluses, the current standard of care. This was followed by a maintenance infusion of DEX versus a normal saline infusion for the control group. Midazolam was given in 0.5 mg increments to maintain an equivalent target level of sedation among the 3 study groups. Fentanyl was given in 25 microg increments to treat pain as needed. The percentage of DEX patients not requiring MDZ and the total dose of MDZ and fentanyl were compared to the control. Dexmedetomidine was efficacious as a sole sedative for 50% of patients. The total dose of MDZ and fentanyl was significantly less during the DEX infusions. Patient satisfaction was superior with DEX.