Update in hospital medicine: Studies likely to affect inpatient practice in 2011

A number of studies published in the last few years will likely affect the way we practice medicine in the hospital. Here, we will use a hypothetical case scenario to focus on the issues of anticoagulants, patient safety, quality improvement, critical care, transitions of care, and perioperative medicine.

AN ELDERLY MAN WITH NEW-ONSET ATRIAL FIBRILLATION

P.G. is an 80-year-old man with a history of hypertension and type 2 diabetes mellitus who is admitted with new-onset atrial fibrillation. In the hospital, his heart rate is brought under control with intravenous metoprolol (Lopressor). On discharge, he will be followed by his primary care physician (PCP). He does not have access to an anticoagulation clinic.

1. What are this patient’s options for stroke prevention?

• Aspirin 81 mg daily and clopidogrel (Plavix) 75 mg daily
• Warfarin (Coumadin) with a target international normalized ratio (INR) of 2.0 to 3.0
• Aspirin mg daily by itself
• Dabigatran (Pradaxa) 150 mg daily

A new oral anticoagulant agent

In deciding what type of anticoagulation to give to a patient with atrial fibrillation, it is useful to look at the CHADS₂ score (1 point each for congestive heart failure, hypertension, age 75 or older, and diabetes mellitus; 2 points for prior stroke or transient ischemic attack. This patient has a CHADS₂ score of 3, indicating that he should receive warfarin. An alternative is dabigatran, the first new anticoagulant agent in more than 50 years.

In a multicenter, international trial, Connolly et al¹ randomized 18,113 patients (mean age 71, 64% men) to receive dabigatran 110 mg twice daily, dabigatran 150 mg twice daily, or warfarin with a target INR of 2.0 to 3.0. In this noninferiority trial, dabigatran was given in a blinded manner, but the use of warfarin was open-label. Patients were eligible if they had atrial fibrillation at screening or within the previous 6 months and were at risk of stroke—ie, if they had at least one of the following: a history of stroke or transient ischemic attack, a left ventricular ejection fraction of less than 40%, symptoms of congestive heart failure (New York Heart Association class II or higher), and an age of 75 or older or an age of 65 to 74 with diabetes mellitus, hypertension, or coronary artery disease.

At a mean follow-up of 2 years, the rate of stroke or systolic embolism was 1.69% per year in the warfarin group compared with 1.1% in the higher-dose dabigatran group (relative risk 0.66, 95% confidence interval [CI] 0.53–0.82, P < .001). The rates of major hemorrhage were similar between these two groups. Comparing lower-dose dabigatran and warfarin, the rates of stroke or systolic embolism were not significantly different, but the rate of major bleeding was significantly lower with lower-dose dabigatran.

In a trial in patients with acute venous thromboembolism, Schulman et al² found that dabigatran was not inferior to warfarin in preventing venous thromboembolism.

Guidelines from the American College of Cardiology Foundation and the American Heart Association now endorse dabigatran as an alternative to warfarin for patients with atrial fibrillation.³ However, the guidelines state that it should be reserved for those patients who:

• Do not have a prosthetic heart valve or hemodynamically significant valve disease
• Have good kidney function (dabigatran is cleared by the kidney; the creatinine clearance rate should be greater than 30 mL/min for patients to receive dabigatran 150 mg twice a day, and at least 15 mL/min to receive 75 mg twice a day)
• Do not have severe hepatic dysfunction (which would impair baseline clotting function).

They note that other factors to consider are whether the patient:

• Can comply with the twice-daily dosing required
• Can afford the drug
• Has access to an anticoagulation management program (which would argue in favor of using warfarin).

Dabigatran is not yet approved to prevent venous thromboembolism.

CASE CONTINUED: HE GETS AN INFECTION

P.G. is started on dabigatran 150 mg by mouth twice a day.

While in the hospital he develops shortness of breath and needs intravenous furosemide (Lasix). Because he has bad veins, a percutaneous intravenous central catheter (PICC) line is placed. However, 2 days later, his temperature is 101.5°F, and his systolic blood pressure is 70 mm Hg. He is transferred to the medical intensive care unit (ICU) for treatment of sepsis. The anticoagulant is held, the PICC line is removed, and a new central catheter is inserted.

2. Which of the following directions is incorrect?

• Wash your hands before inserting the catheter. The accompanying nurse is required to directly observe this procedure or, if this step is not observed, to confirm that the physician did it.
• Before inserting the catheter, clean the patient’s skin with chlorhexidine antiseptic.
• Place sterile drapes over the entire patient.
• Wear any mask, hat, gown, and gloves available.
• Put a sterile dressing over the catheter.

A checklist can prevent infections when inserting central catheters

A checklist developed at Johns Hopkins Hospital consists of the five statements above, except for the second to last one—you should wear a sterile mask, hat, gown and gloves. This is important to ensure that sterility is not broken at any point during the procedure.

Pronovost et al⁴ launched a multicenter initiative at 90 ICUs, predominantly in the state of Michigan, to implement interventions to improve staff culture and teamwork and to translate research into practice by increasing the extent to which these five evidence-based recommendations were applied. The mean rate of catheter-related blood stream infections at baseline was 7.7%; this dropped to 2.8% during the implementation period, 2.3% in the first 3 months after implementation, 1.3% in months 16 through 18, and 1.1% in months 34 through 36, demonstrating that the gains from this quality-improvement project were sustainable.

If this intervention and collaborative model were implemented in all ICUs across the United States and if similar success rates were achieved, substantial and sustained reductions could be made in the 82,000 infections, 28,000 deaths, and $2.3 billion in costs attributed to these infections annually.