RESUMO
OBJECTIVE: Spinal anesthesia is commonly used for cesarean section. Its major adverse effect is hypotension. The objective of this study is to determine the incidence and risk factors of hypotension during spinal anesthesia for cesarean section. MATERIAL AND METHOD: The authors retrospectively reviewed anesthetic records of 991 patients who received spinal anesthesia for cesarean section at Siriraj Hospital. Exclusion criteria were patients with pregnancy included hypertension, received combination of spinal block with other type of anesthesia. RESULTS: The incidence of hypotension (the lowest systolic blood pressure < or = 100 mm Hg) was 76.%. The parameter with increased incidence of hypotension included patient's height < 155 cm (adjusted odd ratio (OR) 1.93, 95%CI 1.19-3.14), baseline systolic blood pressure < or = 120 mmHg (OR 2.14, 95%CI 1.53-2.99) and analgesic level > or = T5 (OR 1.83, 95%CI 1.18-2.84). CONCLUSION: The risk factors associated with increased incidence of hypotension are the patient 's height, baseline systolic blood pressure and level of blockade.