Korean J Anesthesiol.  1987 Dec;20(6):814-823. 10.4097/kjae.1987.20.6.814.

The Effects of Propranolol on Hemodynamic Responaea and Intrapulmonary Shunting during Induced Hypotension with Sodium Nitroprussid in Pstiente Aneethetized with Halothane and Nitrous Oxide

• Lee YG
• Lee CS
• Yoo KY
• Ha IH

• KMID: 2090501
• DOI: http://doi.org/10.4097/kjae.1987.20.6.814

Abstract

Sodium nitroprusside hart become increasingly popular as a vasodilator due to its high potency, rapid onset and reversibility. However, it has some untoward effects including cyanide toxicity, tachyphylaxis, and rebound phenomenon. Accordingly, several attempts to dimmish such complications have been tried including the use propranolol, a possible direct cardiovascular depressant. Therefore, to determine whether propranolol makes a deleterious contribution to hemodynamic responses and impaired in pulmonary gas exchange during SNP in patients anesthetized with halothane-N2O (FiO2; 0.5), experiments were performed on 25 patients with deliberate hypotension scheduled for elective surgery. Thirteen patients were pretreated with divided doses of propranolo (320mg, b.i.d po) and the other twelve were controls. The results were as follows. 1) Cardiac index was significantly lower in pretreated with propranolol than the untreated control in the hypotensive period (3.45+/-0.16 vs 2.97+/-7.141/min/m2, p<0.05). 2) Heart rate increased by 20% in control group during the hypotensive period, but it remained unaltered in propranolol group at all times. 3) Hypotension induced by SNP, resulted from a marked decrease in systemic vascular resistance in both groups. 4) MPAP, PCWP, CVP, SVR, PVR significantly decreased after SNP infusion in both groups, but , they did not differ significantly between the groups at all times. 5) SNP caused a significant increase in intrapulmonary shunt fraction from 8.26+/-0.51 to 10.11+/-0.92%, but propranolo prevented it. 6) Mixed venous oxygen tension was significantly lower in propranolol group than in untreated control group at all times. 7) Patients who .received propranolo required less SNP than the untreated control. (2.51+/-0.22 vs 5.95+/-0.75 mcg/kg/min, p<0.001) These results indicate that propranolol required does not produce any unfavorable hemodynamic event and, furthermore, prevents impairment of pulmonary gas exchange during SNP induced hypotension in patients anesthetized with halothane and nitrous oxide. Therefore, premfdication with propranolol should be considered for patients who are supposed to receive SNP for deliberate hypotension.

MeSH Terms

Halothane*
Heart Rate
Hemodynamics*
Humans
Hypotension*
Nitroprusside
Nitrous Oxide*
Oxygen
Propranolol*
Pulmonary Gas Exchange
Sodium*
Tachyphylaxis
Vascular Resistance
Halothane
Nitroprusside
Nitrous Oxide
Oxygen
Propranolol
Sodium