A comparative study of five different techniques to reduce left ventricular dysfunction during endotracheal intubation.
Thirty-five non-selected, consenting patients were studied during induction of anesthesia before coronary artery bypass grafting. Anesthesia was induced with diazepam, thiopentone and fentanyl, followed by pancuronium. Before induction, 200 MBq Tc 99 m - HSA was given i.v. and ejection fraction (EF) of the left ventricle was measured with a collimated single-crystal probe. The patients were allocated to five groups (seven patients in each) treated with: Group A: nitroglycerin i.v. bolus 4 micrograms x kg-1 given 30-60 s before laryngoscopy; Group B: nitroglycerin i.v. in continuous infusion, 1 micrograms x kg-1 x min-1 started before induction; Group C: two-stage topical anesthesia of the vallecula region and larynx with lidocain; Group D: a combination of nitroglycerin and topical anesthesia (as in Group B and C); and Group E: propranolol i.v. 0.01 mg x kg-1 given 5 min before intubation. All groups reacted in the same way during induction of anesthesia up to the point of laryngoscopy. End-diastolic volume and systemic arterial pressure decreased while cardiac index remained unchanged and EF increased. During laryngoscopy and intubation, however, differences between the groups were evident. Nitroglycerin i.v. as a bolus effectively prevented a reduction in EF and an increase in left ventricular volume. In addition to these beneficial hemodynamic effects, there was a moderate increase in heart rate and a reduction of stroke index. Continuous infusion of nitroglycerin and propranolol i.v. had no effect, since EF fell and left ventricular volume increased. Patients receiving topical anesthesia demonstrated a blunted response to endotracheal intubation with a moderate decrease in EF and an unchanged (Group C) or slightly increased (Group D) left ventricular volume.
Dahlgren
G
G
Department of Cardiothoracic Anaesthetics, Karolinska Hospital, Stockholm, Sweden.
Settergren
G
G
Ohqvist
G
G
Brodin
L A
LA
D000328:Adult; D000368:Aged; D000772:Anesthesia, Local; D002303:Cardiac Output, Low / Q000188:drug therapy / Q000209:etiology*; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007275:Injections, Intravenous; D007442:Intubation, Intratracheal / Q000009:adverse effects*; D007830:Larynx / Q000187:drug effects; D008012:Lidocaine; D008297:Male; D008875:Middle Aged; D005996:Nitroglycerin / Q000008:administration & dosage / Q000627:therapeutic use*; D010614:Pharynx / Q000187:drug effects; D011433:Propranolol; D014132:Trachea / Q000187:drug effects; D016277:Ventricular Function, Left / Q000502:physiology*
D008012:Lidocaine; D011433:Propranolol; D005996:Nitroglycerin