Background and Goal of Study: The rapid recovery of patients and an efficient time management are the goals of ambulatory surgery, making patient selection key in the success of ambulatory surgery centres (ASC). Traditionally, ASA I-II are the most appropriate patients, nevertheless, due to constraints in national healthcare services programs, pressure has been done in order to change selection criteria policy to allow sicker patients (ASA III-IV) to undergo more extensive surgery.
The authors intend to verify if there is any difference in outcome between ASA I-II and ASA III-IV patients in an ambulatory surgery program.
Materials and Methods: A retrospective review was conducted using the database of the ASC, between May 2006 and December 2009.
The statistical analysis was made using the Stata 10.0 software. The averages and standard-deviations were calculated for continuous variables and frequencies for qualitative variables. The Chi-square test was used to compare the two groups.
Results and Discussion: The sample had a total of 4672 patients, with 89,6% in group 1 (ASA I-II) and 10,4% in group 2 (ASA III-IV). Out of the total sample, 38 patients (0,8%) were admitted to the hospital and 56 (2,0%) used a health service in the first 24hours after surgery, with no statistical differences between the groups.
Group 2 had a lower incidence of functional limitations 24hours after surgery than group 1, and this difference is statistically significant (p< 0,01). There is also a statistically significant difference (p< 0,001) between the types of anaesthesia used in both groups, group 1 with 77,7% of general anaesthesias and group 2 with 49,3% of sedation and regional anaesthesia. A statistically significant difference was also observed in terms of surgical specialty (p< 0,01), gynecology and orthopedics more present in group 1 and general and vascular surgeries in group 2.
Conclusion(s): The authors conclude that ASA III-IV patients have identical morbidity as ASA I-II patients, supporting the safety of the patient selection protocol of the ASC.
Nevertheless, ASA III-IV patients have fewer functional limitations post-operativelly and a greater number of sedations and regional anaesthesia, raising the question if they are not being subjected to less complex surgeries and using less aggressive anaesthetic techniques, thereby explaining their better outcome. Further studies to support these results will be needed.
Br J Anaesth 2004;92:71-4
Can J Anaesth 2004;51:782-94