f Anesthesiology increased from 65% in 1981 to 97% in 2002 (P
< 0.001). In 2002, 85% of all active ASA members were certified by the American Board of Anesthesiology. Table 1
shows that the percentage of respondents who render most of their anesthesia care in a subspecialty area is greater than in 1981 (P
= 0.017 for cardiac; P
< 0.001 for neurosurgical, obstetric, and pediatric). The major subspecialties were similarly represented in 2002: 9% cardiac, 9% neurosurgical, 10% obstetric, and 10% pediatric. The size of the primary hospitals where the anesthesiologists practice decreased, but the size of the populations in the areas where they practice increased (both P
< 0.001). The percentage of anesthesiologists who described their anesthesia practice as academic increased from 16% in 1981 to 23% in 2002 (P
< 0.001). According to ASA membership data, approximately 16% of active members belong to a university-associated group.
Seventy-eight percent of those surveyed in 1981 replied that their hospital had a transfusion committee, 11% said it did not, and 11% did not know. These responses differed from the 2002 responses of 82%, 6%, and 12%, respectively (P = 0.007). In 1981, 59% said there was an anesthesiologist on the committee; 65% replied affirmatively in 2002 (P < 0.001).
The percentage of anesthesiologists who responded that it is never or rarely (1% or less of the time) necessary to cancel elective surgery because of nonavailability of blood products was 96% in 2002 (table 2
). In 1981, 92% responded that it was rarely necessary, and 8% said that it was occasionally necessary. In 2002, 9% responded that platelets for intraoperative transfusion are never available unless arrangements are made preoperatively. In 1981, 31% indicated that it was difficult and 3% said that it was very difficult to obtain platelets for intraoperative transfusion in the absence of preoperative arrangements.
Use of Blood Conservation Techniques
The use of apparatus for intraoperative salvage and reinfusion of blood increased from 39% in 1981 to 95% in 2002 (P < 0.001). In 1981, 22% of the respondents replied that they had used acute normovolemic hemodilution; in 2002, 31% indicated that they had used the technique within the previous 12 months.
In 1981, 46% of respondents did not know whether a maximum surgical blood-ordering schedule (MSBOS) was used in their primary hospital; 52% did not know in 2002 (P
= 0.114). The use of a type and screen without crossmatch before surgical procedures in which transfusion might be required increased from 65% in 1981 to 87% in 2002 (P
< 0.001). The percentage of anesthesiologists who require patients undergoing elective surgery to have a hemoglobin concentration of at least 10 g/dl decreased from 65% in 1981 to 9% in 2002 (P
< 0.001). Table 3
shows that there were statistically significant differences in transfusion practices for all of the four case scenarios.
shows that the responses to the methods used for estimating blood loss during major abdominal surgery changed from 1981 to 2002. Measuring the contents of suction containers decreased from 95% in 1981 to 91% in 2002 (P
= 0.01). Visual estimation decreased from 88% in 1981 to 82% in 2002 (P
= 0.005). Use of serial hemoglobin and/or hematocrit determinations increased from 45% in 1981 to 81% in 2002 (P
< 0.001). Weighing sponges decreased from 48% in 1981 to 26% in 2002 (P
In the 1981 survey, erythrocytes were reported to be transfused by 15% of respondents only if vital signs changed (i.e., blood pressure decreased, pulse rate increased significantly). In 2002, 52% relied primarily on vital signs (P < 0.001). One third of anesthesiologists in 2002 transfused before estimated blood loss approached 20% of estimated blood volume; 42% used this criterion in 1981 (P = 0.002). A response indicating transfusion of erythrocytes to adults only if more than 1 U is required changed from 18% in 1981 to 12% in 2002 (P = 0.002). In 2002, 13% indicated that allogeneic whole blood was available in their institutions. Sixty-one percent of respondents to the 2002 sur