THE EFFECTS OF ATRIAL-NATRIURETIC-PEPTIDE INFUSION ON HEMODYNAMIC, RENAL, AND HORMONAL RESPONSES DURING GASTRECTOMY

Atrial natriuretic peptide (ANP) antagonizes the reninangiotensin-aldo sterone, adrenocorticotropic hormone-cortisol, vasopressin, and endoth elin systems. Surgical injury stimulates these systems and causes vaso constriction and antidiuresis. We assessed the hemodynamic, renal, and endocrine effects of continuous intravenous infusion of ANP in patien ts anesthetized with sevoflurane undergoing gastrectomy. ANP (0.1 mu g .kg(-1).min(-1); ANP group, n = 9) or saline (control group, n = 9) wa s infused continuously for 3 h from the start of the operation. The AN P group showed much higher urinary volume and sodium, potassium, and c hloride excretion than the control group, although the former had lowe r arterial blood pressure. ANP infusion slightly inhibited aldosterone secretion and initially tended to inhibit renin secretion stimulated by surgery, but it did not affect surgery-induced increases in the pla sma concentrations of vasopressin, adrenocorticotropic hormone, cortis ol, or endothelin. Two patients in the ANP group experienced excessive hypotension, one experienced bradycardia, and two experienced mild hy poxemia, which required treatment but were resolved easily. These find ings suggest that ANP infusion may be used with caution for controllin g renal function and arterial blood pressure during surgery. Implicati ons: Continuous intravenous infusion of atrial natriuretic peptide, 0. 1 mu g.kg(-1).min(-1), during gastrectomy was associated with higher w ater and sodium excretion and lower arterial blood pressure. It tended to inhibit the renin-angiotensin-aldosterone system compared with sal ine infusion, which suggests that atrial natriuretic peptide may be us eful for intraoperative circulation control.