A 55-year-old banker is driving back to work following a three-martini lunch when he is T-boned by a cement truck. On arrival in the emergency department he is hemodynamically stable and alert. He prides himself on never having graced a physician’s office and he is on no medications. FAST exam reveals fluid in the LUQ. During the next hour his blood pressure drifts down and you are forced to take him to the OR for a splenorrhaphy.
You are writing his postoperative orders using a template, and you arrive at the section with numerous possible options for postoperative β-blockade. As you write your postoperative orders, you wonder: “Should I put this guy on a β-blocker?”
1. Should you put this patient on a β-blocker?
2. If he instead took metoprolol 25 mg PO twice a day at home, what dose would you give him of IV metoprolol while he is NPO?
In 1999, Poldermans et al screened almost 800 high-risk vascular patients with dobutamine stress echocardiography. These investigations then culled approximately 200 very, very high-risk vascular patients formidably vulnerable to myocardial ischemia from the original high-risk group. Two weeks of β-blockade prior to the vascular surgical procedure cut the mortality from 34% (control) to 3.4% (β-blockers)—a huge difference.
However, is it permissible to extrapolate from this very, very high-risk vascular surgical group to just high-risk or even moderate-risk patients? Mangano previously stoked the confusion by prospectively randomizing 200 surgical patients into β-blocker and placebo groups. The 30-day mortality was the same, but 2-year mortality statistically favored β-blockade. Taken together, it began to look like preoperative β-blockers were certainly good for very high-risk patients, probably benefited moderate-risk patients, and might be good for everyone. Extending the tenets of a great American philosopher (Mae West opined that “Too much of a good thing is wonderful”) the PeriOperative ISchemic Evaluation (POISE) trial gave up to eight times the recommended dose of extended-release β-blockers to any patient with a heart rate over 60. In this huge study of 8351 patients in 23 countries (they could not talk any US investigators into participating), there was a reduction in myocardial infarction (5.7%-4.2%; P <.0017), but β-blocked patients with heart rates of 60 induced more strokes (0.5%-1.0%) and more deaths (2.3%-3.1%; P <.03). The investigators did not report whether they were surprised by the results of their pharmacological experiment.
Finally, Lindenaur et al retrospectively correlated cardiovascular events and in-hospital mortality with in-hospital β-blockers—another huge 663, 969-surgical-patient study in which β-blockers clearly benefited high-risk patients. Most low-risk patients were not on a β-blocker on hospital admission. This low-risk group did not receive a β-blocker until subsequent to their cardiovascular event, at which time they were statistically included in the β-blocker group. In fairness, this jaw-dropping experimental design flaw was emphasized in a companion editorial. From the flurry of studies examining perioperative β-blockade, several conclusions are permissible:
- Perioperative myocardial infarction, and probably death, is reduced by judicious use of low-dose, short-acting β-blockers (target a preoperative heart rate of ...