The Influence of Induction Anesthetic Agents on Serum Cortisol Concentration in Morbidly Obese Patients.
Condition: Obesity
Study type: Interventional

Summary: 
      The effect of etomidate administration on the adrenal cortex in obese patients is still
      unclear. The objective of the study was to determine the influence of single dose of
      etomidate on cortisol secretion in morbidly obese. The participants were divided equally into
      etomidate and thiopental groups, depending on kind of intravenous anesthetic used for
      induction of anesthesia.

      Healthy patients in ASA class I and II awaiting elective abdominal laparoscopic surgery were
      included in the study. The participants were initially divided into two groups: the first
      group included patients with morbid obesity (BMI > 40), and the second group included
      patients with normal body weight (BMI < 25). All the patients inside the two groups were
      subsequently randomly and divided into etomidate and thiopental groups, according to the
      intravenous anesthetic used as the induction agent for general anesthesia. Finally, four
      groups of patients were analyzed: 1. obese, in which etomidate was used (OE group), 2. obese,
      in which thiopental was used (OT group), 3. patients with normal body mass, in which
      etomidate was used (NE group), and 4. patients with normal body mass, in which thiopental was
      used (NT group).

      The patients excluded from the study were those who: 1. did not agree to participate, 2. were
      treated with steroidal drugs, 3. had cortisol metabolism disorders or were treated with drugs
      with a potential impact on serum cortisol concentration, 4. had a preoperative risk
      assessment result of ASA class III, IV and V, 5. had an initial surgical laparoscopic
      technique converted to laparotomy, and 6. had surgical complications increasing the level of
      intraoperative stress.
    

Detailed description: 
      One hour before the induction of general anesthesia midazolam was administered orally as a
      premedication. After the patient's arrival in the operating theater, standard monitoring was
      commenced. All the patients were oxygenated. Depending on the study group, either etomidate
      or thiopental was used as an induction agent for general anesthesia. Both anesthetics were
      administered according to ideal body weight. When the ciliary reflex disappeared, either
      suxamethonium chloride or rocuronium bromide was administered, depending on the possible
      problems in endotracheal intubation. The general anesthesia was maintained with desflurane,
      continuous intravenous infusion of remifentanil, and repeated doses of rocuronium bromide as
      required.

      Each patient had their serum cortisol concentration level measured five times. The first
      measure was taken the afternoon of the day before surgery (A sample), and the second two
      hours after induction of anesthesia with etomidate or thiopental (B sample). Subsequently a
      short stimulation test with intravenous injection of 250 μg of tetracosactide, a synthetic
      analogue of adrenocorticotropic hormone (ACTH), was performed. The third sample was taken
      thirty minutes after the short stimulation test blood (C sample), and next, the fourth (D)
      sample was taken 24 hours after induction of anesthesia. Immediately afterwards, a second
      short stimulation test with 250 μg of tetracosactide was performed, and 30 minutes later, the
      fifth blood sample (E sample) was taken.

      The serum cortisol concentration was measured by electrochemiluminescence.

      The patients' participation of the study ended when the last, fifth blood sample was
      withdrawn.
    

Intervention name(s): Intravenous administration of the induction agent of general anesthesia (etomidate or thiopental)
Intervention type(s): Drug
Intervention MeSH terms: Thiopental; Etomidate
Allocation: Randomized
Intervention model: Factorial Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: etomidate,; thiopental,; serum cortisol concentration,