The circulatory stimulation accompanying laryngoscopy and tracheal intubation and its attendant potential hazards are well recognized. This study was perfomed to compare cardiovascular effects of rapid sequence induction with slow induction
during
induction of anesthesia and following tracheal intubation with laryngoscope.
Eighty six adult patients - ASA class I or II, ages 20-55, with no previous history of hypertension and pulmonary diseases - that undergoing elective surgery requiring intubation, were admitted to the study. These patients were randomly divided
into
four groups.
Group 1. Rapid sequence induction (n=20)
Group 2. Slow induction for 7min. (n=20)
Group 3. Slow induction for 10min. (n=21)
Group 4. Slow induction for 15min. (n=25)
Anesthesia was induced with lidocaine 1.5mg/kg and thiopental sodium 5mg/kg i.v. in a rapid sequence induction n group 1. Tracheal intubation with laryngoscope was facilitated with succinylcholine chloride 1mg/kg iv. Thereafter 50% nitrous oxide
in
oxygen, 2.0 vol% enflurane, and vecuronium bromide .01mg/kg was administered.
Group 2, 3, 4, patients received thiopental sodium 5mg/kg iv, vecuronium bromide 0.1mg/kg iv, 2.0 vol% enflurane and 50% nitrous oxide in oxygen with mask ventilation for 7 min, 10 min and 15 min before intubation with laryngoscope, respectively,
After
tracheal intubation inhalation of the anesthetic gases were administered. Blood pressure and heart rate measurements and electrocardiography were obtained throughout the study period.
Slow induction (Group 2, 3, 4) significantly blunted the increase in heart rate and blood pressure caused by laryngoscopy and endotracheal intubation than rapid sequence induction than rapid sequence induction (group 1). Less unwanted effects
were
observed in group 2 and 3.
Therefore, the author suggests that 7-10 minute of slow induction with volatile anesthetics following thiopental sodium injection is more effective in attenuating cardiovascular responses to tracheal intubation and laryngoscopy.
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