The pre-operative electrocardiogram: an assessment

Current preoperative testing practices in ambulatory surgery are widely disparate: a survey of CAS members

PURPOSE

Routine preoperative testing has been criticized as having little impact on perioperative outcomes. The purpose of this study is to identify the current practice of preoperative testing in ambulatory surgery.

METHODS

A standard questionnaire was sent to all active members of the Canadian Anesthesiologists' Society (CAS). The study inquired into the anesthesiologist's preoperative testing practice in healthy patients and patients with stable medical conditions undergoing ambulatory surgery.

RESULTS

Of 1,335 mailed questionnaires, a total 617 respondents who reported their participation in ambulatory surgical care were received. Eighty percent [95% confidence interval (CI) 76.5-83.2] of the respondents indicated that, if testing had to be ordered in asymptomatic patients undergoing low-risk ambulatory surgery, it would be due to the patient's clinical indications while others indicated it would be the result of following institutional guidelines (15.1%, 95% CI 12.2-17.9), and even fewer attributed it to a "routine" testing practice (0.5%, 95% CI 0-1.14). Forty-four percent (95% CI 39.8-47.8) of the anesthesiologists indicated that age alone is not a criterion when they required a preoperative electrocardiogram (ECG) while others reported various cut-points (> 65; > 55; > 45; > 40 yr) for ECG ordering for asymptomatic patients undergoing the low-risk ambulatory surgery. About 40% (95% CI 35.7-43.5) of the anesthesiologists had no specific concern about eliminating preoperative testing in ambulatory surgery.

CONCLUSION

Our survey has documented marked disparities in the practices of preoperative testing. A large proportion of the anesthesiologists indicated that age alone is not a criterion for preoperative ordering of ECG. Many anesthesiologists had no concern about eliminating preoperative testing in low-risk ambulatory surgery.

[Cost analysis and potential savings related to the use of preoperative tests in the hospitals of the Canary Islands [Spain]]

OBJECTIVE

To estimate the potential cost savings that might take place in the Canary Islands Health Service (CHS) through the appropriate scientific use of preoperative tests, using information obtained from five public university hospitals.

METHODS

A questionnaire was completed by 55 anesthesiologists, representing 60% of the total in the CHS. The questionnaire paid special attention to the most frequently used preoperative tests: chest radiograph, electrocardiogram, laboratory tests, and spirometry. The mean unit costs for the various preoperative tests were obtained from the two hospitals participating in the study. To calculate the potential cost savings derived from the appropriate use of preoperative tests, several scenarios were considered. These were characterized by different hypotheses or degrees of fulfillment of a protocol based on scientific knowledge and considered as the gold standard.

RESULTS

In the ideal scenario in which the recommended scientific protocol was fulfilled in 100% of the 16 179 patients with an American Society of Anesthesiologists (ASA) grade of I-II, the economic impact would be notable, since it would free sensitive resources that could be used for other health programs. These figures could amount to approximately 1.02 million euros, without considering the cost of preoperative hospital stay. This figure could increase by up to approximately 2.13 million euros if one day of preoperative hospital stay were included and by up to 3.24 million euros if two days of preoperative hospital stay were included.

CONCLUSIONS

The recent literature review and the results of the questionnaire applied in the CHS indicate that preoperative tests are of greatest benefit to patients and to society if their use is guided by scientific knowledge. In addition, resources can be freed by better selection and utilization of preoperative tests.

Utilisation of the pre-operative ECG

The utilisation of the pre-operative ECG in patients undergoing routine surgery was investigated in 354 adult patients over a 2-week period. Sixty-four percent of patients had an ECG pre-operatively. An ECG was not performed in 17% of patients who, current hospital policy suggests, should have had one. In contrast, an ECG was performed in 33% of patients who, hospital policy suggests, have no need of one (all of which were normal), which represented 18% of the total number of pre-operative ECGs performed. In 62% of patients with known cardiac disease, and 44% of patients with strong risk factors for ischaemic heart disease (in the absence of known disease) the ECG was abnormal. This compares with only 7% of patients aged over 50 with no risk factors in whom the ECG was abnormal. These findings suggest that there is room for improvement in the utilisation of the pre-operative ECG, which may have cost implications.

Preoperative laboratory testing: should any tests be "routine" before surgery?

Routine preoperative testing of all patients before elective surgery is unjustified. The frequency of unanticipated abnormalities or abnormalities shown to change patient management is too low to justify a practice pattern of testing all patients. Furthermore, little evidence exists that test result abnormalities are associated with perioperative morbidity. Table 12 lists a compilation of the findings from this article and recommendations regarding routine testing.

[Evaluation of a protocol for selective ordering of preoperative tests in healthy subjects]

A protocol for selective ordering of 12 preoperative tests was prospectively evaluated during one year in a teaching hospital. 1600 consecutive healthy patients had an average of 2.4 tests each, but 270 of them had none. Usefulness of tests was assessed by taking into account not simply their abnormality yield, but also their impact on patient care during the whole hospital stay in the anaesthetist view. The possible value of tests omitted was assessed by anaesthetists at the end of hospital stay. As a consequence of test results, surgery was delayed in one patient, and a treatment was started or the anaesthetic management adapted in 16.7% of tests performed (279/3905) were found to be useful and 0.1% of tests not carried out (21/15295) would have been potentially useful. No complication inducing sequelae or death could be linked to tests not carried out. This study showed that routine preoperative investigations in healthy patients could be avoided without any adverse effects on patient care.

Rational preoperative evaluation

Clinical data from two hundred consecutive patients undergoing surgical procedures at the Salt Lake City VA Hospital form the basis of this study. Results of nine commonly ordered preoperative tests (blood count, differential, electrolytes, chemistry panel, urinalysis, prothrombin time, partial thromboplastin time, electrocardiogram, and chest X-ray) were matched with the preoperative history and physical examination and the outcome of surgery in each patient. Each test was examined by the frequency with which it was ordered, the frequency with which it was abnormal, and the frequency with which the abnormal result affected preoperative care. A prevalence of medical illness was found in this population, with 47.5% having a major cardiovascular diagnosis, 35.5% a metabolic or endocrine disease, and 28% a major pulmonary diagnosis. A total of 1271 tests were performed, with 477 (35.5%) showing some abnormality. However, only 76 (5.9%) changed the patient's management before surgery. All but five of these abnormalities were predictable from the clinical evaluation and these five were minor. The overall postoperative complication rate was 9%. No complication was attributed to the omission of a preoperative test. No surgical cases were cancelled during the study period based solely on a preoperative test. We conclude that many preoperative tests can be safely eliminated by ordering only those based on a specific abnormality in the history or physical examination, resulting in more cost-effective surgical care.