The Effects of Anesthesia and Pulmonary Ventilation on Blood Loss during Elective Therapeutic Abortion

Abstract

Uterine blood loss was measured in 87 healthy women undergoing elective therapeutic abortion while anesthetized with any of eight anesthetic or ventilatory techniques. A 1 per cent alveolar concentration of halothane produced the highest mean blood loss (283 ml); reduction of halothane to 0.5 per cent and addition of 75 per cent nitrous oxide decreased mean blood loss to 169 ml. Addition of thiopental and meperidine to the halothane–nitrous oxide mixture increased the blood loss to that seen with 1 per cent halothane. Blood loss with 5 per cent alveolar fluroxene was 233 ml. Eighty per cent nitrous oxide plus intravenous thiopental and meperidine yielded a blood loss of 58 ml. Blood losses with all anesthetics, except nitrous oxide plus adjuvants, were significantly larger than the 25-ml loss observed with paracervical-block anesthesia. Hyperventilation (PaCO2 less than 20 torr) did not reduce blood loss significantly in two groups of patients anesthetized with either 0.5 per cent halothane and nitrous oxide or 75 per cent nitrous oxide plus intravenous adjuvants.