The Thai Anesthesia Incidents Monitoring Study (Thai AIMS) of Adverse Events after Spinal Anesthesia: An Analysis of 1,996 Incident Reports
Piyamart Sirivararom MD*, Tanit Virankabutra MD*, Nate Hungsawanich MD**, Porntep Premsamran MD***, Wimonrat Sriraj MD****
Affiliation : * Department of Anesthesiology, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand ** Department of Anesthesiology, Prasat Neurological institute, Ministry of Public Health, Bangkok, Thailand *** Department of Anesthesiology, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Chulalongkorn University, Bangkok, Thailand **** Department of Anesthesiology, Khon Kaen University, Khon Kaen, Thailand
Background : To study the incidents of complications, adverse events and anesthetic profiles of spinal anesthesia
from primary to tertiary hospitals across Thailand.
Material and Method: The present study is a descriptive research design. Participating anesthesia providers
are requested to report the standardized incident reporting form as soon as they find the predetermined
adverse or undesirable events during anesthesia until 24 hours after the operation. Data from the incident
report were reviewed and analyzed to identify contributing factors and preventive strategies by consensus by
three-peer reviewers. The objections were discussed and the decision was made in order to achieve general
agreement.
Results : One hundred and sixty-seven cases adverse events after spinal anesthesia were reported from fifty-one
hospitals across Thailand. Eighty-five cases (50.9%) were male; eighty-two cases (49.1%) were female. Seventy
cases (41.9%) occurred in patients whose age was more than 60 years. One hundred and thirty-one cases
(78.4%) had ASA I and II, seventy cases (41.9%) occurred spontaneously whereas ninety-seven cases (58.1%)
were considered as preventable. Most of the incidents (74.4%) were bradycardia (HR < 50 beats per minute).
The others were hypotension (18.6%), respiratory complications (hypoxia and pulmonary edema) (5.4%),
myocardial infarction (3.6%), and cardiac arrest (6.6%). Most of the incidents (88.6%) were detected by EKG,
pulse oximeter (64.7%), and NIBP (71.3%) respectively. Anesthetic factors and systemic factors that found to
be involved in all cases were high spinal block, inadequate prehydration and delayed resuscitation. Most
of the contributing factors were inappropriate decision making (45%), inexperienced performers (20%),
inadequate preoperative evaluation and preparation (19%). The incidents should be minimized by having
prior experience, high awareness and experienced assistants available.
For immediate outcome that occurred within 24 hours, eighteen cases (10.8%) had major
physiological change such as hypoxia, pulmonary edema, myocardial infarction or neurological deficit. Ten
cases (6%) died within 24 hours and one case (0.6%) had cardiac arrest intra-operative period. For long term
outcome within 7 days, one hundred and fifty-seven reported cases (94%) had complete recovery; fourteen
cases (8.4%) had prolonged hospital stay and ventilatory days.
Conclusion : To minimize the adverse events after spinal anesthesia, the authors suggest corrective strategies
which include established guideline practice, additional training, improved supervision and having quality
assurance activity in each hospital.
Keywords : Adverse events, Spinal anesthesia, Bradycardia, Cardiac arrest, Hypotension, Myocardial infarction
