CHARACTERISTICS OF ARTERIAL-HYPERTENSION IN RESPONSE TO BOLUS INJECTION OF PHENYLEPHRINE IN ATROPINIZED PATIENTS

The changes of arterial pressure promoted by bolus injection of 50 mg phenylephrine (PHE) were studied in 20 atropinized patients (5 normal subjects, 13 patients with mitral valve disease, 1 patient with essent ial arterial hypertension and 1 patient with hypertrophic cardiomyopat hy) submitted to routine catheterism. Patients with aortic valve disea se, left ventricular outflow tract obstruction and intracardiac shunt were excluded from the study. All patients were in sinus rhythm, witho ut heart failure. Arterial pressure started to increase at 14.8 +/- 5. 4 s (range, 5.6 to 27 s; mean +/- SD) after PHE. There was an increase of 37.8 +/- 16.7 mmHg (range, 12.5 to 70 mmHg) in systolic pressure a nd of 26.6 +/- 11.1 mmHg (range, 7.5 to 42.5 mmHg) in diastolic pressu re. Peak hypertension was attained at 36.6 +/- 16.4 s (range, 10.8 to 64.9 s) and hypertension continued for 176 +/- 92 s (range, 11 to 365 s). Heart rate was 114 +/- 21 bpm before PHE and 111 +/- 21 bpm (P<0.0 5) after PHE. There were no adverse events associated with intravenous PHE injection in any patient, in accordance with the general view tha t bolus injection of PHE is a safe and practical maneuver to promote a rterial hypertension.