Learning Objectives: After reading this article, the physician should be able to:
1. Describe the risk of aggressive treatment of incidental or asymptomatic hypertension in the emergency department.
2. Summarize the need for caution when using the Broselow tape to estimate a child's weight, particularly with obese children.
3. Identify effective strategies used by hospitals and health care systems to reduce door-to-balloon time in acute myocardial infarction.
Release Date: April 2009
Article from the 2009 Reading List
Clinical Policy: Critical Issues in the Evaluation and Management of Adult Patients with Asymptomatic Hypertension in the Emergency Department
Decker WW, et al
Ann Emerg Med
Hypertension is the most common chronic disease of adults in the United States affecting up to 20 percent of the population. In many patients, hypertension is asymptomatic, and elevated blood pressure is an incidental finding during ED visits for other complaints. Blood pressure may be temporarily elevated by conditions such as pain, nausea, anxiety, or intoxication, all of which are highly prevalent in the emergency department. The authors of this clinical policy reviewed the relevant literature in an attempt to generate recommendations regarding the safe treatment of high blood pressure in the emergency department.
Researchers looked at whether ED blood pressure readings were accurate and reliable for screening asymptomatic patients for hypertension. Multiple observational studies of ED patients were reviewed, which consistently showed that initial blood pressure readings are often elevated in nonhypertensive individuals. Repeating BP measurements after a period of observation improved their specificity, but up to a third of patients with a diastolic blood pressure above 95 mm Hg on repeated ED measurements had normal blood pressure without treatment at a one-week follow-up. The authors recommend:
▪ If blood pressure measurements are persistently elevated above 140/90 mm Hg, the patient should be referred for follow-up of possible hypertension. (Level B)
▪ Patients with a single elevated blood pressure reading may require further screening as outpatients. (Level C)
Investigators also explored whether asymptomatic patients with elevated blood pressure benefit from rapid lowering of their blood pressure. The authors note that there are little data regarding lowering blood pressure in the ED, but earlier trials of antihypertensives versus placebo in severely elevated but asymptomatic hypertension failed to show any benefit during the first three months of treatment. Additionally, no difference between follow-up blood pressure was noted among those “loaded” on antihypertensives in the ED versus those discharged with a prescription for routine blood pressure medication. More importantly, the authors point to extensive literature regarding the potential harm in abruptly lowering chronically elevated blood pressure, including stroke, MI, and death.
The authors note that only patients with active end-organ damage should have blood pressure lowered emergently, but that no consensus exists regarding optimal screening for such damage, beyond a comprehensive history and physical examination. Their three Level B recommendations are:
▪ Initiating treatment for asymptomatic hypertension in the ED is not necessary when patients have follow-up.
▪ Rapidly lowering blood pressure in asymptomatic patients in the ED is unnecessary and may be harmful in some patients.
▪ When ED treatment for asymptomatic hypertension is initiated, blood pressure management should attempt to gradually lower blood pressure, and should not be expected to normalize the BP during the initial ED visit.
Article from the 2008 Reading List
Use of the Broselow Tape May Result in the Underresuscitation of Children
Nieman CT, et al
Acad Emerg Med
Resuscitation of the critically ill child presents many challenges for the emergency physician, one of the most important of which is the selection of appropriately-sized equipment and properly dosed medications. Most medications used in pediatric patients are based on weight, which cannot be easily measured in critical situations. Visual estimates, age-based estimates, and estimates from parents are not as accurate as length-based systems of weight estimation, the most common of which is the Broselow color-coded system. To estimate weight, the child's length is measured with a fold-out chart (the Broselow tape); the estimated weight, drug dosages, and color code for equipment are then noted. Previous studies have reported an error rate of up to 40 percent for the Broselow tape. In this study, the authors seek to further elucidate the accuracy of the Broselow tape, in light of the 2002 update to the system and the increasing incidence of childhood obesity.
The authors obtained height and weight data in an urban clinic and suburban school cohort. Each patient's height was then plotted onto the Broselow tape to determine the color-code assigned, the estimated weight, and the recommended endotracheal tube size. The investigators then compared these estimates with the actual observed weights and age-based endotracheal tube size recommendations. Outcomes included the percent difference in observed versus estimated weight and the rate of inaccurate ET size recommendation for all groups.
Overall, the authors found that only 55 percent to 60 percent of children had their weight estimated to within 10 percent accuracy by using the Broselow tape. The most common error was underestimation, with 31 percent of children's weight underestimated by more than 10 percent, and 15 percent of school-aged (5–11 years) children's weight underestimated by more than 20 percent. Additionally, 13 percent of infants (1–12 months of age) had their weight overestimated by more than 10 percent. The school-aged children in the urban clinic cohort were more likely to be obese than the suburban children (24% versus 14%), and were more likely to have their weight underestimated. In addition, the recommended endotracheal tube size was less than that estimated by PALS age-based guidelines in up to 30 percent of patients over 1 year.
In their discussion, the authors note the inferior performance of the Broselow tape in this population with that observed in prior studies in the United States and Europe and to studies of parental estimates of weight. They ascribe this increase in error to the rising rate of obesity, particularly in urban children. The significance of this error is not known, as many drugs used in resuscitation are not lipophilic, and lean body mass is likely a better dosing guide. It is not known whether a 10 percent over- or underdose of medication in these situations has any clinical importance, given that many of these drugs may be titrated to effect. The authors recommend considering additional measures for estimating the weight of an obese child, such as arm circumference, or better documentation of recent weights in a rapidly accessible electronic medical record.
Article from the 2008 Reading List
Strategies for Reducing the Door-to-Balloon Time in Acute Myocardial Infarction
Bradley EH, et al
N Engl J Med
Acute ST-segment elevation myocardial infarction (STEMI) is a true emergency requiring immediate intervention aimed at restoring myocardial perfusion and salvaging as much myocardial tissue as possible. Numerous studies have shown strong correlation between reduced time to reperfusion and improved clinical outcomes. The AHA/ACC consensus recommendation to limit door-to-balloon (DTB) time to less than 90 minutes has been adopted by the Centers for Medicare and Medicaid Services (CMS) as a core measure of hospital quality. Unfortunately, only a fraction of PCI-capable hospitals are able to meet this goal for the majority of their STEMI patients. Previous studies have demonstrated wide variability across hospitals and an overall median of 105 minutes for DTB time nationwide.
The authors selected 500 institutions from a CMS database of hospitals that report DTB time as a quality measure. A web-based survey was administered to a designee at each institution, asking about the presence or absence of 28 previously identified key clinical strategies for reducing DTB time. The survey results were then used to construct a multivariate model attempting to identify those interventions that predicted shorter DTB times as recorded in the CMS database.
Of the 28 strategies surveyed, six independently correlated with a significant decrease in DTB time in the multivariate model. The expected difference in time associated with each strategy was also reported with these results:
▪ The emergency physician rather than the cardiologist activates the catheterization laboratory: −8.2 minutes.
▪ The emergency department makes a single call to a central page operator to contact the interventional cardiologist and activate the catheterization laboratory: −13.8 minutes.
▪ The emergency department activates the catheterization laboratory while the patient is still en route to the hospital based on an EMS transmitted ECG: −15.4 minutes.
▪ The expected interval between page and arrival of catheterization laboratory staff is less than 20 minutes as opposed to 30 minutes or more: −19.3 minutes.
▪ An attending cardiologist is always at the hospital: −14.6 minutes.
▪ The hospital gives real-time feedback on DTB time to all staff involved: −8.6 minutes.
Hospitals that utilized two or more of the above key strategies had a median DTB time of 88 minutes; those that used none or one had medians of 110 and 100 minutes, respectively. Sites that involved activation of the catheterization laboratory by the emergency physician were associated with a slightly higher rate of unnecessary activations having two “false alarms” every six months as opposed to only one.
The authors note that some strategies are easier to implement than others. Twenty-four hours of cardiology attending coverage is expensive, and catheterization laboratory personnel may live more than 20 minutes from some hospitals. Emergency physicians should be responsible for activating the catheterization team, preferably based on the prehospital ECG while the patient is en route, to minimize door-to-balloon time. In some institutions, this will be a departure from standard practice. The authors also noted that the strategies may be surrogates for other unmeasured variables, and may not affect door-to-balloon time at all institutions given the observational nature of the study.
Luis M. Lovato, MD, an Associate Clinical Professor at the David Geffen School of Medicine at UCLA, the Director of Critical Care in the Department of Emergency Medicine at Olive View-UCLA Medical Center, and the Medical Editor of www.emcme.com, serves as the medical editor of this column.
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