A dose-response study of phenylephrine in critically ill, septic surgical patients.
OBJECTIVE
To determine the response of haemodynamic and oxygen-transport parameters to phenylephrine in a dose-response fashion in septic non-hypotensive, vasodilated surgical intensive care unit (ICU) patients.


METHODS
Prospective study.


METHODS
Surgical ICU of a tertiary care, university medical centre.


METHODS
Ten septic non-hypotensive, vasodilated surgical ICU patients.


METHODS
Routine ICU monitoring, including pulmonary and radial artery catheters.


METHODS
Haemodynamic and oxygen-transport measurements were taken at baseline and during-therapy. Phenylephrine was infused intravenously for 3 h at progressively increasing doses of 0.5, 1.0, 2.0, 3.0, 4.0, and 8.0 micrograms.kg-1.min-1 at 30-min intervals. Measurements were taken after each dose.


RESULTS
Mean arterial pressure (MAP) and systemic vascular resistance (SVRI) increased linearly with phenylephrine dose. Cardiac index and pulmonary artery occlusion pressures did not change. Statistically significant changes were observed in heart rate, MAP, stroke index, and systemic and pulmonary vascular resistance. Eight patients had a clinically significant increase (> 15%) in oxygen consumption (VO2I). Oxygen delivery (D2OI) increased in only three patients. Serum lactate concentrations were unchanged or lower at the end of the study in all eight patients, who displayed a 15% increase in VO2I.


CONCLUSIONS
Treatment with phenylephrine increased expected haemodynamic parameters in a linear fashion; however, clinical changes in VO2I occurred at variable doses. Dose-response trials are needed to determine the optimal dose of phenylephrine. Further study is needed to evaluate the clinical effects of phenylephrine in septic patients.
Flancbaum
L
L
Department of Surgery, Ohio State University, Columbus 43210, USA.
Dick
M
M
Dasta
J
J
Sinha
R
R
Choban
P
P
D018806:APACHE; D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D003422:Critical Care; D004305:Dose-Response Relationship, Drug; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007022:Hypotension / Q000188:drug therapy* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000187:drug effects; D010656:Phenylephrine / Q000008:administration & dosage / Q000627:therapeutic use*; D011446:Prospective Studies; D018805:Sepsis / Q000150:complications / Q000503:physiopathology*; D013514:Surgical Procedures, Operative
D000316:Adrenergic alpha-Agonists; D010656:Phenylephrine