The Thai Anesthesia Incidents Study (THAI Study) of Ambulatory Anesthesia: II Anesthetic Profiles and Adverse Events
Yodying Punjasawadwong MD*, Sureerat Srisawasdi MD**, Thewarug Werawatganon MD***, Kanok Taratarnkoolwatana MD****, Waraporn Chau-in MD*****, Mayuree Vasinanukorn MD******
Affiliation : * Department of Anesthesiology, Chiang Mai University, Chiang Mai ** Department of Anesthesiology, Ramathibodi Hospital, Mahidol University, Bangkok *** Department of Anesthesiology, Chulalongkorn University, Bangkok **** Department of Anesthesiology, Ratchaburi Hospital, Ratchaburi ***** Department of Anesthesiology, Khon Kaen University, Khon Kaen ****** Department of Anesthesiology, Prince of Songkla University, Songkhla
Background : There is a continuing trend to have more elective surgery performed on an outpatient basis.
Objective : To determine anesthetic profiles and adverse events in practice of ambulatory anesthesia for elective surgery in
different levels of hospitals across Thailand.
Material and Method: A prospective descriptive study was conducted in 20 hospitals comprising seven university, five
regional, four general and four district hospitals across Thailand. Consecutive patients undergoing anesthesia for elective
surgery were included. The included patients, classified as outpatients, were selected and extracted for summary of the result
by using descriptive statistics.
Results : The authors reported 7786 outpatients receiving anesthesia for elective surgery. The majority of patients were in ASA
class 1 and 2 (96.2%) while the rest were in ASA class 3 (3.8%). Nearly 90% of the ASA class 3 patients were in university
hospitals. The majority of patients (83.1%) did not receive premedication. Diazepam was used more frequently (11.5% vs.
0.1%) than other drugs. Noninvasive blood pressure monitoring and pulse oximetry were used in greater than 90%, while
electrocardiogram (EKG) was used in 67.2% and end tidal CO2 in only 6.8%. The three most common anesthetic techniques
were general anesthesia (including inhalation anesthetics), total intravenous anesthesia (TIVA), and monitored anesthesia
care (MAC). Regional anesthesia was performed in 12% of cases. The three most common regional anesthetic techniques
were brachial plexus block (7.1%), spinal anesthesia ( 2.21%), and other peripheral nerve blocks (2.06%). Propofol was the
most common drug for induction. Succinylcholine was used for intubation in 8.8%. The three most common nondepolarizng
neuromuscular blocking agents were atracurium, cisatracurium, and vecuronium. Fentanyl was the most common drug used
among opioids. The three most common volatile anesthetics were sevoflurane, halothane, and isolurane. Lidocaine was the
most frequently used in 29.76% of cases, while bupivacaine in 7.9% and ropivacaine only in 0.05%. The majority of the
events relating to respiratory system were hypoxia or oxygen desaturation (18:10,000), reintubation (2.6:10,000) and
difficult intubation (2.6:10,000), pulmonary aspiration (2.6:10,000), and esophageal intubation (1.3:10,000). Other adverse
events included awareness (1.3:10,000), suspected myocardial infarction or ischemia (1.3:10,000), and drug error (1.3:10,000).
Five patients (0.06%) received unplanned hospital admission. No patients developed cardiac arrest or died.
Conclusion : The incidence of major adverse events was low in ambulatory anesthesia for elective surgery when compared
to the incidence in general surgical population. The majority of the events occurred in the respiratory system. The authors did
not find any complications relating to regional anesthesia. Despite a low incidence of adverse events in ambulatory anesthe-
sia, anesthesia personnel who are responsible for ambulatory anesthesia should have adequate knowledge and skills in
selection and preparation of the patients. Therefore, a system of preanesthesia evaluation is very important.
Keywords : Ambulatory, Anesthesia, Outpatient
