Characteristic N Percent
Surgical intervention
Cardiothoracic surgery 34 9.1
Obstetrics 29 7.8
Vascular surgery 9 2.4
Orthopedic surgery 8 2.1
ENT 6 1.6
General surgery 5 1.3
Gynecology 1 0.3
Plastics 0 0
Neurology 0 0
Pain medicine 133 35.6
Multiple subspecialties 140 37.4
Other 9 2.4
Location
Europe 162 43.3
United States 90 24.1
Australia/Asia 49 13.1
Canada 46 12.3
South America 2 0.5
Africa 1 0.3
Multiple 24 6.4
First author anesthesiologist 171 45.7
Anesthesiology journal 146 39.1
ENT = Ear, Nose, and Throat.
Table 1: Characteristics of Included Studies.