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Forecasting the Impact of a Clinical Practice Guideline for Perioperative  -Blockers to Reduce Cardiovascular Morbidity and Mortality
Michael Schmidt, BS;
Peter K. Lindenauer, MD, MSc;
Jan L. Fitzgerald, MS, RN;
Evan M. Benjamin, MD
Arch Intern Med. 2002;162:63-69.
ABSTRACT
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Background  -Blockers reduce morbidity and mortality
when administered to high-risk patients undergoing major noncardiac surgery,
yet little is known about how often they are being prescribed. Clinical practice
guidelines are tools that can be used to speed the translation of research
into practice and may be one method to improve the use of -blockers.
Before implementing any guideline, it is important to forecast its potential
clinical and financial impact.
Methods We conducted a retrospective cohort study, using administrative and
medical record review data, of all adult patients undergoing major noncardiac
surgery at Baystate Medical Center, Springfield, Mass, during a 1-month period
in 1999. Patients with 2 or more cardiac risk factors or with documented coronary
artery disease were classified as high risk and were considered eligible for
treatment with a -blocker if they had no obvious contraindications to
its use. We estimated the potential clinical benefit of treating eligible
patients with a -blocker by extrapolating the treatment effect observed
in a previously reported randomized clinical trial.
Results Of 158 patients undergoing major noncardiac surgery, 67 (42.4%) seemed
to be ideal candidates for treatment with perioperative -blockers. Of
these 67 patients, 25 (37%) received a -blocker at some time perioperatively.
During the course of a year, we estimate that between 560 and 801 patients
who do not receive -blockers might benefit from treatment with these
medications. Full use of -blockers among eligible patients at our institution
could result in 62 to 89 fewer deaths each year at an overall cost of $33 661
to $40 210.
Conclusions There seems to be a large opportunity to improve the quality of care
of patients undergoing major noncardiac surgery by increasing the use of -blockers
in the perioperative period. A clinical practice guideline may be one method
to achieve these goals at little cost.
INTRODUCTION
PERIOPERATIVE myocardial ischemia and myocardial infarction are important
causes of morbidity and mortality among patients undergoing major noncardiac
surgery.1-4
At highest risk are the estimated 7 to 8 million patients with multiple cardiac
risk factors or with established coronary artery disease (CAD).1, 3
By slowing the heart rate, decreasing blood pressure, and moderating hemodynamic
stress responses, -blockers reduce the incidence of perioperative myocardial
ischemia.5-7 In
a recent Veterans Affairs hospital randomized controlled trial,8
the perioperative administration of the -blocker atenolol to high-risk
patients resulted in significant reductions in mortality and cardiovascular
complications beginning at 6 months and extending to 2 years following surgery.
Following this report, the American College of Physicians9
recommended that -blockers be considered for perioperative use in all
high-risk patients undergoing major noncardiac surgery. More recently, bisoprolol
was shown to reduce mortality when administered perioperatively to high-risk
patients undergoing vascular surgery.10 Although
we are not aware of any studies documenting how often perioperative -blockers
are used in routine practice, if practice patterns in patients with myocardial
infarction can serve as a guide, it is quite possible that these medications
are being underused.11-12
Clinical practice guidelines are "systematically developed statements
to assist practitioner decisions about appropriate health care for specific
clinical circumstances."13 They are one of
several tools intended to speed the translation of research findings into
routine clinical practice.14-19
While individual studies20-23
of the effectiveness of clinical practice guidelines have demonstrated mixed
results, a systematic review24 of the guidelines'
literature supports their continuing role in quality improvement initiatives.
We developed a clinical practice guideline, based on the eligibility criteria
and treatment protocol used in a recent randomized controlled trial,8 to improve the use of -blockers in patients
undergoing major noncardiac surgery at our institution. Before implementing
this guideline, we sought to forecast its clinical and financial impact.
Our main objective was to estimate the number of patients undergoing
major noncardiac surgery at our institution who might benefit from perioperative -blockers
but who do not receive these medications. We used this information to estimate
the clinical and financial impact if our guideline were reasonably successful
in meeting its goals.
PATIENTS AND METHODS
DESCRIPTION OF THE INSTITUTION
The study was performed at Baystate Medical Center, Springfield, Mass,
a 550-bed community-based teaching hospital that serves as the western campus
for Tufts University School of Medicine, Boston. The hospital is a regional
referral center for a population of almost 1 million residents of western
New England.
GUIDELINE AND STUDY DESIGN
Relying on information contained in prior clinical trials and incorporating
the input of a multidepartmental task force, we developed a practice guideline
for perioperative -blocker use. The guideline consists of a series of
treatment recommendations that include specific eligibility criteria, dosing
and monitoring recommendations, and a detailed treatment algorithm. Plans
for dissemination and implementation of the guideline included a mailing to
all anesthesiologists, surgeons, and internists on the medical staff; presentations
at appropriate grand rounds and noon conferences; and the development of an
online version of the recommended order set using the hospital's electronic
physician order entry system. Implementation plans called for providing partial
salary support to a faculty physician to serve as a "clinical champion" for
the project. This physician was expected to maintain awareness of the guideline
through lectures and informal discussions, through individualized academic
detailing, and by being available to discuss questions or problems related
to the guideline. As an additional implementation measure, we planned to have
the hospital case manager for surgery play an active role in identifying eligible
patients and reminding physicians about the availability of the guidelines.
The study was a retrospective cohort analysis using administrative and
medical record review data of patients undergoing major noncardiac surgery
at our institution.
DESCRIPTION OF THE PATIENTS
All patients undergoing surgery in the institution's main operating
suites between January 2, 1999, and February 2, 1999, were identified using
the hospital's computerized database to determine potential eligibility. Surgery
that took place outside this arena was limited to "day-stay" procedures. Patients
who were 18 years and older and who underwent major noncardiac surgery were
considered potentially eligible. Surgical procedures considered major for
this study were determined by a group of physicians and nurses representing
the departments of surgery, anesthesiology, and internal medicine. These procedures
include the following: orthopedic procedures, including total knee/hip replacement,
bipolar hip replacement, open reduction internal fixation (hip or pelvis),
and limb amputation; vascular procedures, including aortofemoral bypass, abdominal
aortic aneurysm repairs, and any other surgery on the aorta; intra-abdominal
procedures, including colectomy, splenectomy, pancreatoduodenectomy (Whipple
procedure), radical prostatotomy, radical hysterectomy, liver resection, nephrectomy,
and total abdominal hysterectomy/bilateral salpingo-oophorectomy; and intrathoracic
procedures, including all invasive noncardiac procedures. We excluded patients
undergoing day-stay surgery and those who underwent a second surgical procedure
during a single hospitalization. Demographic data, including age, sex, race,
type of surgery, length of hospital stay, and prior use of -blockers,
were collected for all potentially eligible patients.
ELIGIBILITY FOR TREATMENT WITH PERIOPERATIVE -BLOCKERS
A 2-step process was used to determine patient eligibility for treatment
with perioperative -blockers. The first step identified all patients
meeting the guideline definition of high perioperative risk. The eligibility
criterion was established CAD (including any one of the following: prior myocardial
infarction, classic angina, atypical angina with a positive stress test result,
history of coronary revascularization, or cardiac catheterization showing
significant stenosis) or being at high risk for CAD (including at least 2
of the following: 65 years or older, having hypertension, currently smoking,
having a total serum cholesterol level  240 mg/dL [6.21 mmol/L], or
having diabetes). The second step consisted of screening all high-risk patients
for conditions that might be a contraindication to -blocker use (including
poorly controlled reactive airway disease [asthma or chronic obstructive pulmonary
disease], decompensated congestive heart failure, bradyarrhythmia [heart rate
<55 beats/min without a pacemaker], sick sinus syndrome, second- or third-degree
heart block, a systolic blood pressure <100 mm Hg, or carotid hypersensitivity).
High-risk patients who had no obvious contraindications to -blocker
use were considered to be ideal candidates for treatment with perioperative -blockers
according to our guideline.
DATA COLLECTION AMONG IDEAL CANDIDATES
For those patients who seemed to be ideal candidates for treatment with
a -blocker, we recorded the following: whether a -blocker was
used at any time during the hospital course, the development of potential
contraindications to -blocker use postoperatively, the ability to take
oral medications following discharge from the postanesthesia critical care
unit, the prescription of a -blocker at discharge, the incidence of
postoperative tachycardia (defined as a recorded heart rate 100 beats/min
at any time during the postoperative course), and in-hospital death.
IMPACT ON MORBIDITY AND MORTALITY
In the clinical trial by Mangano et al,8
patients who received -blocker therapy had higher overall and event-free
survival at 6 months, 1 year, and 2 years compared with those receiving a
placebo. The 1-year mortality of 14% in the placebo group and 3% in the atenolol-treated
group results in a number needed to treat to prevent 1 death of 9. The 1-year
cardiovascular complication rate of 22% in the placebo group and 8% in the
atenolol-treated group results in a number needed to treat to prevent 1 cardiovascular
complication of 7. We extrapolated the results from that study to estimate
the potential impact the implementation of this guideline might have on morbidity
and mortality at our institution. Recognizing the limited effectiveness of
clinical practice guidelines, even when they are aggressively implemented
using proved methods, we estimated that only 50% of the patients who appeared
to be ideal candidates, and yet were not receiving -blockers, would
likely be administered a perioperative -blocker as recommended by our
guideline. In other words, we assumed that the guideline would be successful
in 50% of the cases.
CALCULATION OF COSTS AND POTENTIAL SAVINGS
To provide an estimate of the costs of developing and implementing this
guideline, we considered the medical and the administrative costs that would
likely be incurred. We also estimated the potential savings associated with
a forecasted reduction in cardiovascular events during the course of 1 year.
Estimates of medical costs were based on the marginal drug and telemetric
monitoring costs for the additional patients who we predicted might receive -blocker
treatment. Drug costs reflect pharmacy acquisition costs for generic oral
and intravenous atenolol at the study institution's pharmacy in February 2000.
Our guideline recommends intravenous atenolol for patients who are unable
to take oral medications postoperatively. Moreover, it is the clinical policy
at our institution that a patient undergo telemetry when intravenous -blockers
are used. We estimated the additional cost of telemetric monitoring by multiplying
the expected number of patient-days in which postoperative telemetry would
be required by the daily cost for telemetric monitoring. Costs were obtained
directly from the hospital's cost-accounting system (Health Management Systems,
El Segundo, Calif).
Estimates of the administrative costs incurred in developing and implementing
the guideline were based on several factors. These included the following:
the costs of supporting 10% of the annual salary of the physician who served
as the clinical champion during the program's first year and 5% during subsequent
years, the costs of supporting 20% of the salary of the surgical case manager
each year, the computer programming costs associated with developing online
versions of the recommended order sets, and the printing and mailing costs
to distribute the guideline to the medical staff.
We used the average cost of caring for a patient with an acute myocardial
infarction (International Classification of Diseases, Ninth
Revision, Clinical Modification code 410) at the study institution
in 1999 to estimate the potential cost savings associated with a reduction
in cardiovascular events that might be expected each year. The cost for caring
for patients within this International Classification of
Diseases, Ninth Revision, Clinical Modification code was obtained from
the hospital cost-accounting system. We multiplied this figure by the forecasted
number of cardiovascular events averted each year to estimate the potential
savings resulting from the guideline.
RESULTS
During the 1-month study period, 1132 patients were admitted to the
institution's main operating room. Of these patients, 212 met the age and
type of surgery inclusion criteria. Medical records were readily available
for 158 (75%) of these patients. Of the 158 study subjects, 81 (51%) were
found to have either established CAD or 2 or more major risk factors. Of these
81 patients, 14 (17%) had a contraindication to -blocker use. The remaining
67 patients (42% of the total study group) seemed to be ideal candidates for
treatment with -blockers according to our guideline (Figure 1).
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Overview of the study design and data collection decision tree.
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STUDY PATIENTS
Demographic information on the subgroup of patients who seemed to be
ideal candidates for -blocker treatment and on the patients not eligible
for treatment is presented in Table 1.
There is a significantly higher proportion of men among ideal patients compared
with those not eligible. The distribution of type of surgery also differs
significantly between the groups, with higher rates of vascular and orthopedic
surgery among the ideal patients and lower rates of abdominal and thoracic
surgery in this group.
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Characteristics of Patients Eligible for -Blockers and Those
Not Eligible or With Contraindications*
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As expected, based on eligibility criteria, ideal patients tended to
be older, with a higher proportion having established CAD and having more
CAD risk factors present. The one exception we found was smoking, which was
more common among the ineligible patients. Thirty-three patients overall (21%)
were taking -blockers before hospital admission.
PERIOPERATIVE -BLOCKER USE AND HOSPITAL COURSE AMONG IDEAL -BLOCKER
CANDIDATES
Of the 67 ideal patients, 25 (37%) who we predicted might benefit from -blocker
therapy had received a -blocker at some time perioperatively. If we
include use before admission, this increases to 31 (46%) of the ideal patients.
Of the 42 patients who were not taking -blockers before admission, 6
(14%) had them initiated during hospitalization. Another 6 patients (6 [24%]
of the 25 taking -blockers before admission) did not continue taking
them during the hospital stay. Almost all patients who were admitted to the
hospital while taking -blockers (30 [91%] of 33 patients) were prescribed
them at discharge.
Of the 67 ideal patients, 21 (31%) were unable to take medications by
mouth for an average of 3 days following surgery. Twenty (30%) of the ideal
candidates developed a new contraindication to -blocker use at some
time postoperatively. Of these contraindications, hypotension (1 reading
of a systolic blood pressure of <100 mm Hg) was the most common, and was
found in 17 (25%) of the eligible patients. Four patients had -blockers
discontinued secondary to a contraindication. Postoperative tachycardia was
observed in 25 (50%) of the 50 ideal patients who did not receive a -blocker
and in 12 (50%) of the 24 ideal patients who did receive -blocker treatment.
Of 42 eligible patients who did not receive a -blocker perioperatively,
5 (12%) died before hospital discharge compared with 0 of the 25 patients
who received treatment.
PROJECTED CLINICAL IMPACT OF THE PRACTICE GUIDELINE
A 95% confidence interval on the observed proportion (42%) of patients
eligible indicates that we can expect between 35% and 50% of patients undergoing
major noncardiac surgery to be eligible for treatment with perioperative -blockers.
In light of the annual number of these operations carried out at our institution,
we expect between 890 and 1272 patients per year to be eligible for treatment.
Based on our observations, we anticipate that only slightly more than one
third (25 [37%] of 67 patients) are already receiving a perioperative -blocker.
Therefore, each year, some 560 to 801 patients who seem to be ideal candidates
are not receiving treatment. If our guideline is 50% successful, then some
280 to 400 ideal candidates who are not receiving this therapy would begin
receiving -blocker therapy perioperatively each year. Twenty (30%) of
the 67 patients developed at least one potential contraindication to -blockers
postoperatively. Taking this into account, we estimate that approximately
196 to 280 patients would be able to tolerate treatment with -blockers
for the duration of their hospitalization.
Extrapolating the benefit observed in the Veterans Affairs' study, in
which the number of patients needed to treat to prevent a single death at
1 year was 9, we estimate that as many as 62 to 89 additional patients might
be alive at 1 year if all ideal candidates at our institution were to receive
this treatment. Taking into account the limited effectiveness of guidelines
in changing physician behavior, and the likelihood that some patients will
not tolerate -blocker therapy, we estimate 22 to 31 lives saved each
year. Similarly, if all ideal candidates were to receive -blocker treatment,
we would anticipate 80 to 114 fewer cardiovascular events each year (number
needed to treat, 7). Discounting the effectiveness of the guideline and the
tolerability of -blocker therapy, we predict 28 to 40 fewer cardiovascular
events during the course of each year as a result of our intervention.
PROJECTED COSTS AND POTENTIAL SAVINGS
Additional drug cost estimates for oral and intravenous atenolol are
$3087 to $4393 per year, and the cost for additional monitored beds is from
$15 399 to $21 948. Thus, the total medical cost of guideline implementation
at the study institution was estimated to be $18 486 to $26 348
per year.
Administrative costs included $12 000 in the first year for physician
salary support and $6000 per year in subsequent years, $10 000 per year
for nurse case management, and 1-time programming and printing and mailing
costs of $4185 and $1125, respectively. Thus, the total administrative costs
were projected to be $27 310 in the first year and $16 000 in subsequent
years. During the first 5 years, the average administrative cost of developing
and implementing this guideline is projected to be $18 262 per year.
Taking into account medical and administrative factors, we estimate $33 661
to $40 210 in annual costs attributable to the perioperative -blocker
guideline or $1297 to $1530 per life saved.
Given predictions of 28 to 40 fewer annual cardiovascular events and
an average cost per myocardial infarction at the study institution of $12 588,
we estimate annual savings of $352 464 to $503 520. Balancing these
savings against the costs of developing and implementing this guideline results
in overall savings of $318 803 to $463 310.
COMMENT
In a recent review, the American College of Physicians9
recommended that all high-risk patients undergoing major noncardiac surgery
be considered for treatment with a -blocker in the perioperative period.
We sought to forecast the impact of a clinical practice guideline designed
to assist clinicians in following these recommendations. We estimated the
proportion of patients undergoing major noncardiac surgery who were likely
to be classified as high risk using the criteria from our guideline and identified
practice patterns surrounding perioperative -blockade. We found that
51.3% of the patients undergoing major noncardiac surgery had either established
CAD or at least 2 major risk factors for CAD—and, thus, were classified
as being at high risk for major postoperative complications. After excluding
patients with known contraindications to -blocker therapy, we found
that 63% (n = 42) of this population did not receive a perioperative -blocker.
If all ideal candidates at our institution were to receive this treatment,
we estimate that an additional 62 to 89 patients might be alive at 1 year
and that 80 to 114 patients might survive 1 year without a major cardiovascular
complication. Taking into account the challenges of achieving full compliance
with any practice guideline and the tolerability of -blockers, we anticipate
28 to 40 fewer cardiovascular events and 22 to 31 fewer deaths each year.
The administrative and direct medical expenses required to fully implement
this guideline were estimated to be $33 661 to $40 210 per year.
Considering the potential savings associated with anticipated reductions in
cardiovascular complications such as acute myocardial infarction, use of this
guideline in the perioperative period would be anticipated to save between
$318 000 and $463 000 annually.
There are several limitations to the present study. First, patient eligibility
for treatment with -blockers was determined retrospectively via medical
record review. Retrospective classification of eligibility status may differ
from eligibility classification performed during real clinical time because
of, for example, incomplete patient histories in the medical record. However,
this is unlikely to be a major source of error in the present study, as most
of the CAD diagnosis and risk factor data came from preoperative anesthesia
records, which we believe reflect a reasonably accurate assessment of cardiovascular
risk. Second, the present study population includes only patients undergoing
major noncardiac surgery. We developed this definition after obtaining the
input of an internist, an anesthesiologist, a surgeon, and a nurse, but may
have excluded some procedures that could arguably be considered major. As
the definition of what constitutes major surgery changes, the proportion of
high-risk patients would change as well. For example, if total abdominal hysterectomy
and bilateral salpingo-oophorectomy—which are predominantly performed
on younger women without a history of CAD—were not considered major
surgery, the overall proportion of patients undergoing major surgery who are
eligible for the protocol would increase.
Our method for estimating the clinical impact of the proposed guideline
also has several significant limitations. First, evidence supporting the efficacy
of perioperative -blockers in reducing morbidity and mortality is not
extensive,5, 8, 10
and only 2 clinical trials8, 10
have examined the effects of -blocker therapy administered during the
entire hospital stay. Our forecast of clinical impact assumes that the effects
observed by Mangano et al8 are generalizable.
However, differences between the 2 study populations, such as in case mix
or severity, may result in differences in the impact of -blocker therapy
on mortality and morbidity. We used eligibility criteria to select patients
who were nearly identical to those used in the Veterans Affairs study. This
should have the effect of adjusting for some of the differences between a
veterans hospital's population and the population at an urban community-based
teaching hospital. This is supported by a similar distribution of CAD diagnosis
and CAD risk factors between the 2 studies. One notable difference between
the 2 study populations is the use of an all-male population in the veterans
hospital clinical trial. To the extent that sex modifies the beneficial effect
of -blocker therapy or significantly alters the risk of postoperative
mortality and morbidity, error in the present study's estimates would result.
We recognize that clinical practice guidelines are only one of several techniques
used to improve quality of care and that the effectiveness of such interventions
is often limited. We estimated that we would be successful in achieving 50%
compliance with our guideline by incorporating several proved implementation
techniques. Although this estimate may be either overly optimistic or alternatively
too pessimistic, it falls within the range of reported compliance in other
guideline trials25-26 that used
similar implementation techniques.
Our methods used to quantify the expected number of patients who will
develop a contraindication to -blockers have several limitations. Most
notably, our assessment of contraindications did not fully take into account
actual -blocker use (only 25 [37%] of 67 patients took a -blocker
at least once). Those patients who did take a -blocker in the present
study were more likely to have been taking a -blocker before hospital
admission and, thus, less likely to develop a new contraindication because
of use. By including these patients in our calculation, we may have significantly
underestimated the proportion of patients likely to develop a contraindication
after beginning treatment with a -blocker. Alternatively, our estimates
of new-onset contraindications may overestimate the number of patients who
would have to terminate treatment. For example, any study patient with a systolic
blood pressure lower than 100 mm Hg on a single measurement was considered
to have a new contraindication. However, it is unlikely that a single episode
of mild hypotension would always be viewed as clinically meaningful and result
in termination or suspension of treatment. Indeed, we found that many patients
who were taking a -blocker postoperatively continued to receive these
medications even after we noted a potential contraindication, such as a low
systolic blood pressure.
Owing to the retrospective nature of this study, we were unable to detect
subtle, yet important, clinical outcomes such as myocardial ischemia or subclinical
myocardial infarction. We found similar rates of tachycardia in the -blocker–treated
and the nontreated groups; however, we only measured the overall frequency
of postoperative tachycardia and were not able to quantify the time patients
spent tachycardic or the mean heart rate postoperatively. Although it is possible
that patients who received -blockers were suboptimally treated, our
methods of measuring the effect of -blockade were not sensitive enough
to detect clinically important differences between the 2 groups. Furthermore,
because treatment assignment was not random, we were not confident in attempting
to compare the clinical outcomes of the treated with those of the nontreated
patients.
A major contributor to our estimate of the cost of fully implementing
this guideline was the cost of telemetric monitoring for patients who receive
nothing by mouth following surgery—because these patients may require
treatment with intravenous -blockers. Although our hospital requires
that telemetric monitoring be used for patients taking intravenous -blockers,
this may not be the case at other institutions. Moreover, we assumed that
telemetric monitoring would be required for the entire time that patients
were to receive nothing by mouth, yet it is conceivable that this monitoring
could be limited to the first several doses of medication. In addition to
calculating drug and monitoring costs, we estimated the administrative costs
required to develop and implement this guideline. These included the costs
of a physician champion, a nurse case manager to provide real-time reminders
to clinicians, an electronic version of the guideline and order set programmed
into the hospital electronic physician order entry system, and printing and
mailing. While these techniques increase the likelihood that a guideline will
be adopted by clinicians,27 not all institutions
are likely to commit this level of support. Finally, we estimated potential
savings resulting from a reduced incidence of cardiovascular complications
during the course of 1 year using the cost of caring for a single episode
of myocardial infarction at our own institution. Although we considered these
savings taking the perspective of society, we recognize that many hospitals
would not reap any financial benefit from reducing the incidence of complications
6 months following discharge.
CONCLUSIONS
If -blocker therapy is a beneficial treatment for high-risk patients
in the perioperative period, enhancing -blocker use should be a priority.
The use of a clinical practice guideline is one possible technique for improving
the use of perioperative -blocker therapy in high-risk patients undergoing
major noncardiac surgery. Nevertheless, it is often difficult to foresee the
applicability and the likely costs and benefits of a practice guideline before
its implementation. For this reason, some researchers28-29
have suggested that retrospective analyses be used to forecast the impact
of clinical guidelines before their implementation. We believe that this study
provides a reasonable estimate of the clinical and financial impact of a perioperative -blocker
guideline by retrospectively applying guideline criteria to a population of
consecutive patients undergoing major noncardiac surgery. We found that many
of these patients (51%) are at high risk for perioperative complications and
that most do not receive perioperative -blockers. If practice at our
hospital reflects care occurring at similar institutions, then there is a
sizable opportunity to improve the care of patients undergoing major noncardiac
surgery nationwide. Based on this analysis, the use of a clinical practice
guideline or other measures intended to improve the use of perioperative -blockers
in high-risk patients should be strongly considered.
AUTHOR INFORMATION
Accepted for publication April 19, 2001.
We thank Penelope Pekow, PhD, for her advice and assistance, and Alan
Kulig, MD, for his leadership in developing and implementing the perioperative -blocker
guideline.
Corresponding author and reprints: Peter K. Lindenauer, MD, MSc,
Division of Healthcare Quality, Baystate Medical Center, 759 Chestnut St,
P-5928, Springfield, MA 01199 (e-mail: Peter.Lindenauer{at}bhs.org).
From the Department of Biostatistics and Epidemiology, University of
Massachusetts at Amherst (Mr Schmidt); the Department of Medicine, Tufts University
School of Medicine, Boston (Drs Lindenauer and Benjamin); and the Department
of Medicine (Drs Lindenauer and Benjamin) and the Division of Healthcare Quality
(Drs Lindenauer and Benjamin and Ms Fitzgerald), Baystate Medical Center,
Springfield, Mass.
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