se when the hemoglobin concentration is less 10 g/dl, and 6% do not administer erythrocytes until the hemoglobin concentration is less than 6 g/dl. A greater number (52%) rely on changes in vital signs (i.e.
, decreased blood pressure, significant increases in pulse rate) when transfusing erythrocytes than in 1981 (15%). The use of lower transfusion triggers combined with clinical evaluation is consistent with the ASA Guidelines, as well as the recommendations of other organizations. 18,27,28
Coagulation testing is performed routinely (> 85% of the time) by 31% or sometimes (6–85% of the time) by 44% of anesthesiologists before administration of platelets, FFP, or cryoprecipitate in the OR. The responses indicate that transfusion of these components is generally consistent with the ASA Guidelines. Exceptions are the prophylactic administration of platelets to patients with idiopathic thrombocytopenic purpura and infusion of volumes of FFP different from those recommended in the ASA Guidelines. Many respondents cited the lack of readily available coagulation testing in the OR as a problem. Although combining coagulation test results with clinical evaluation is optimal, a limitation to the widespread use of point-of-care coagulation testing is infrequent use. In addition, many of these tests have a different normal range than the hospital laboratory tests do, potentially confusing interpretation of test results. Few of the responding anesthesiologists transfused large volumes of blood on a regular basis. Thus, point-of-care coagulation testing might rarely be used, bringing its cost effectiveness into question.
Autologous transfusion practices have changed. In 1981, only 49% of respondents indicated that a mechanism was established in their hospitals for patients to predonate blood for elective surgery. The same question was not repeated on the 2002 survey, but it is assumed that predonation is more widely available as a result of current requirements that patients undergoing elective surgery be offered alternatives to allogeneic transfusion. When predonated autologous blood is available, 61% use the same criteria for transfusion as for allogeneic blood, whereas 39% administer autologous blood more liberally. Although controversial, the ASA Guidelines support the latter practice. Ninety-five percent of respondents indicated that equipment is currently available for intraoperative autologous transfusion, whereas only 38% had such equipment for intraoperative blood salvage and reinfusion in 1981. The frequency of use of acute normovolemic hemodilution is unknown. However, the percentage of respondents indicating that they had used acute normovolemic hemodilution was 22% in 1981, and 31% of respondents to the 2002 survey indicated that they had used the technique within the previous 12 months.
There are multiple possible limitations to our study. Surveys measure people's perceptions and not necessarily reality. Respondents also may give responses that they consider correct or expected rather than indicating their actual practices. Because this survey was sponsored by the ASA, it is possible that respondents may have given answers consistent with ASA publications, rather than their actual behavior. It is of interest that the necessity to cancel elective surgery because of nonavailability of blood has decreased since 1981, although many of the anesthesiologists surveyed indicated that blood shortages were a major concern. As with all surveys, the data derived are only as good as the survey instrument and the sampling of the population. Our survey instrument was a modification of a previous survey to allow comparisons with the previous survey, and every effort was made to make it a valid survey tool. A randomization process was used to obtain a random sample of active ASA members. There is bias in our study population because only active members of the ASA were surveyed and a large percentage of academic anesthesiologists responded. Finally, the results of the survey only reflect the impressions of those who returned the survey,