The Thai Anesthesia Incidents Study (THAI Study) of morbidity after spinal anesthesia: A multi-centered registry of 40,271 anesthetics

Abstract

Background: The present study was part of the Thai Anesthesia Incidents Study (THAI Study) of anesthetic adverse outcomes. Objective: Study complications after spinal anesthesia. Material and Method: During the 12 month period (March 1, 2003 - February 28, 2004), a prospective multi-centered descriptive study was conducted in 20 hospitals comprised of seven university, five tertiary, four general and four district hospitals across Thailand. Anesthesia personnel filled up patient-related, surgical-related, and anesthesia-related variables and adverse outcomes of all consecutive patients receiving anesthesia on a structured data entry form. The data were collected during pre-anesthetic, intra-operative, and 24 hr post operative period. Adverse event specific forms were used to record when these incidents occurred. Data were reviewed by three independent reviewers and analyzed to identify contributing factors by consensus. Results: This was registry of 40,271 spinal anesthetics from 172,697 anesthetics. The incidence of total spinal anesthesia, neurological complications, suspected myocardial ischemia, or infarction and oxygen desaturation per 10000 spinal anesthetics were 3.48 (95% CI 1.66-5.30), 1.49 (95% CI 0.30-2.68), 2.73 (95% CI 1.12-4.35), 0.99 (95% CI 0.39-2.56), and 6.46 (95% CI 3.98-8.94) respectively. This was not different to the incidence in other countries. Risk factors of oxygen desaturation were shorter in height [OR 0.95 (95% CI 0.92-0.97); p < 0.001], higher ASA physical status [OR 3.37 (95% CI 1.98-5.72); p < 0.001], and use of propofol [OR 5.22 (95% CI 1.78-15.35); p = 0.003]. Other complications such as seizure, anaphylactic or anaphylactoid reaction, drug error, and pulmonary aspiration were scarce. There was no case of mismatched blood transfusion in the present study. Conclusion: Incidence of total spinal block, neurological complication, and suspected myocardial ischemia or infarction was uncommon. Risk factors of oxygen destruction were shorter in height, higher ASA physical status, and use of propofol. Some events were considered avoidable and preventable.