(2) Dexmedetomidine With Ketamine in Procedural Sedation of Obese Patients Suppresses the Decline in Oxygen Saturation

Abstract:

Background: Obesity is rapidly increasing in many countries and is a major public health concern. Obesity is generally defined as a body mass index ≥30 kg/m2 and is further categorized as Class I (BMI: 30-34.9 kg/m2), Class II (BMI:35-39.9 kg/m2) and Class III (BMI: >40kg/m2). Other than morbidity of obesity, sedation in obese patients is challenging due to airway obstruction and rapid oxygen desaturation as a result of respiratory depressant effects of sedatives. Obesity compromises multiple systems and is a risk factor for GERD and metabolic and cardiovascular diseases. As lipophilic sedative agents accumulate in adipose tissues, pharmacokinetics and pharmacodynamics of drugs are altered in obese patients. As a result, anesthesiologists face significant challenges, and the primary aim of the project is to determine the optimal drug agent and strategy for target sedation.
Materials and

Method: A retrospective study of patients ≥12 years old who were sedated for elective dental procedures at Oral and Maxillofacial Surgery, LSU Health Shreveport was performed. Patients were stratified by BMI Class I ( < 35 mg/kg2), Class II (35 to < 40 mg/k2), and Class III (>40 mg/kg2). The primary outcome was the sedative strategy to achieve ideal level of oxygen saturation through the procedure.
Results and

Discussion: In our study, 368 patient records of procedural sedation at one of the oral and maxillofacial surgery clinics at LSU Health Shreveport were reviewed. Based on BMI, 114 patients were determined to be obese (BMI >30). Of these, 27 patients were severely obese (BMI >35) and 25 patients were morbidly obese (BMI >40). The common combination of anesthetics for procedural sedation in patients included midazolam, fentanyl, and propofol with dexmedetomidine alone or in combination with ketamine. The assessment of oxygen saturation during the procedure identified 13 patients (11.4%) in whom SpO2 < 95% during the sedation. In 6 of 13 patients (46.2%), dexmedetomidine was used alone, while dexmedetomidine with ketamine was used in 3 of 13 (23.1%). Dexmedetomidine causes bradycardia and hypotension in patients and our results show that patients administered dexmedetomidine were more likely to show a reduction in blood oxygen saturation than with dexmedetomidine in combination with ketamine. Ketamine induces a transient increase in blood pressure, heart rate, and cardiac output by its sympathomimetic action and could counteract bradycardia and hypotension of dexmedetomidine. Our results suggest that dexmedetomidine be complemented with ketamine for use in obese patients.