Update in hospital medicine: Studies likely to affect inpatient practice in 2011
KEY POINTS
- Dabigatran (Pradaxa) will likely start to replace warfarin (Coumadin) both to prevent stroke in patients with atrial fibrillation and to prevent recurrent venous thromboembolism.
- Using a checklist during insertion of central venous catheters can decrease the rate of catheter-related bloodstream infections in the intensive care unit.
- The overall survival rate of patients who undergo cardiopulmonary resuscitation in the intensive care unit is approximately 16%; the rate is lower in patients who are receiving pressor drugs and higher in those with ventricular tachycardia or ventricular fibrillation.
- Patients lacking follow-up with a primary care physician within 30 days of discharge are at high risk of readmission and have a trend for longer length of hospital stay.
- Preoperative stress testing for patients undergoing noncardiac surgery should be done selectively, ie, in patients at high risk.
Is cardiac testing necessary before noncardiac surgery?
Wijeysundera et al7 performed a retrospective cohort study of patients who underwent elective surgery at acute care hospitals in Ontario, Canada, in the years 1994 through 2004. The aim was to determine the association of noninvasive cardiac stress testing before surgery with survival rates and length of hospital stay. Included were 271,082 patients, of whom 23,991 (8.9%) underwent stress testing less than 6 months before surgery. These patients were matched with 46,120 who did not undergo testing.
One year after surgery, fewer patients who underwent stress testing had died: 1,622 (7.0%) vs 1,738 (7.5%); hazard ratio 0.92, 95% CI 0.86–0.99, P = .03. The number needed to treat (ie, to be tested) to prevent one death was 221. The tested patients also had a shorter mean hospital stay: 8.72 vs 8.96 days, a difference of 0.24 days (95% CI −0.07 to −0.43; P < .001).
However, the elderly patients (ie, older than 66 years) who underwent testing were more likely to be on beta-blockers and statins than those who did not undergo testing, which may be a confounding factor.
Furthermore, the benefit was all in the patients at intermediate or high risk. The authors performed a subgroup analysis, dividing the patients on the basis of their Revised Cardiac Risk Index (RCRI; 1 point each for ischemic heart disease, congestive heart failure, cerebrovascular disease, diabetes, renal insufficiency, and high-risk surgery).8 Patients with an RCRI of 0 points (indicating low risk) actually had a higher risk of death with testing than without testing: hazard ratio 1.35 (95% CI 1.03–1.74), number needed to harm 179—ie, for every 179 low-risk patients tested, one excess death occurred. Those with an RCRI of 1 or 2 points (indicating intermediate risk) had a hazard ratio of 0.92 with testing (95% CI 085–0.99), and those with an RCRI of 3 to 6 points (indicating high risk) had a hazard ratio of 0.80 with testing (95% CI 0.67- 0.97; number needed to treat = 38).
Comment. These findings indicate that cardiac stress testing should be done selectively before noncardiac surgery, and primarily for patients at high risk (with an RCRI of 3 or higher) and in some patients at intermediate risk, but not in patients at low risk, in whom it may be harmful. Stress testing may change patient management because a positive stress test allows one to start a beta-blocker or a statin, use more aggressive intraoperative and postoperative care, and identify patients who have indications for revascularization.
