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A comparative study of five different techniques to reduce left ventricular dysfunction during endotracheal
G Dahlgren1, G Settergren, G Ohqvist
1Department of Cardiothoracic Anaesthetics, Karolinska Hospital, Stockholm, Sweden.
Acta Anaesthesiologica Scandinavica
|October 1, 1991
Summary
Intravenous nitroglycerin bolus effectively preserves left ventricular ejection fraction during anesthesia induction for coronary artery bypass grafting. Other treatments like continuous nitroglycerin, propranolol, or topical anesthesia were less effective.
Area of Science:
- Cardiology
- Anesthesiology
- Cardiovascular Surgery
Background:
- Coronary artery bypass grafting (CABG) surgery requires careful anesthetic management to maintain hemodynamic stability.
- Induction of anesthesia and endotracheal intubation can precipitate adverse cardiac events, particularly in patients with compromised cardiac function.
- Left ventricular ejection fraction (LVEF) is a critical indicator of cardiac performance during surgical procedures.
Purpose of the Study:
- To evaluate the efficacy of different anesthetic interventions in preserving left ventricular ejection fraction (LVEF) during induction for CABG.
- To compare the hemodynamic effects of intravenous nitroglycerin bolus, continuous nitroglycerin infusion, topical anesthesia, and propranolol.
- To assess the impact of these interventions on left ventricular volume and systemic arterial pressure.
Main Methods:
- Thirty-five patients undergoing CABG were studied during anesthetic induction.
- Left ventricular ejection fraction (LVEF) was measured using radionuclide ventriculography (Tc 99m - HSA).
- Patients were randomized into five groups receiving: IV nitroglycerin bolus, continuous IV nitroglycerin, topical anesthesia, combination therapy, or IV propranolol.
Main Results:
- An intravenous bolus of nitroglycerin effectively prevented the decrease in LVEF and increase in left ventricular volume during laryngoscopy and intubation.
- Continuous nitroglycerin infusion and propranolol administration did not preserve LVEF, with observed decreases and increases in ventricular volume.
- Topical anesthesia showed a blunted response, with a moderate decrease in LVEF and unchanged or slightly increased left ventricular volume.
Conclusions:
- A bolus of intravenous nitroglycerin is a superior method for maintaining left ventricular ejection fraction during anesthetic induction for CABG.
- Continuous nitroglycerin infusion and propranolol are less effective in preserving cardiac function during this critical period.
- Topical anesthesia provides some protection but is less effective than nitroglycerin bolus in preventing adverse hemodynamic changes.