nfidence interval assuming a point estimate of 50%.
The percentages should total 100 within round-off error and excluded those who left the question unanswered or indicated that it was not applicable. In some questions, more than one answer could be given (Appendix 2
, questions 5, 7, 9, 10, 11, 13, 15, 23, 25, and 32). We analyzed those questions on an individual response basis, and the total percentage response may be greater than 100%. In cases where additional questions are asked after an initial response, the percentage responses for the follow-up question were reported based on the total number of initial question responses (Appendix 2
, questions 6, 8, 26, 27, and 28). For these follow-up questions, the total percentage may be less than 100% if responses were missing or greater than 100% if more than one answer could be given.
There were 389 respondents for the 1981 survey. Comparisons of 2002 to 1981 were made using the chi-square test for equality of endorsement percentages. In all cases, two-tailed P values of 0.05 or less were considered evidence of differences not attributable to chance.
Of the 2,500 questionnaires mailed, a total of 1017 surveys were returned, for a 41% response rate. Of these, 862 respondents provided or directly supervised anesthesia for patients who required transfusion. Further analysis was based on this population of 862 anesthesiologists. A copy of the questionnaire is attached as Appendix 2
The majority of respondents never or rarely (62%) or only one to five times a week (37%) transfused 3 or more units of blood to the same patient in a typical workweek. There was a change in the profile of the physician considered primarily responsible for ordering and administering blood products intraoperatively. In 1981, 53% said the anesthesiologist was responsible, 2% said it was the surgeon, and 45% considered it a joint responsibility. The responses in 2002 were 33%, less than 1%, and 67%, respectively (P < 0.001).
The percentage of survey respondents certified by the American Board of 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%