Transcript Journal review July 2007 - Stellenbosch University

Journal review July 2007
Heike Geduld
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Journal Clubs in South Africa
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Highlight latest research
Improve clinical practice
Teach principles and practice of EBM
Senior staff should have minimal core understanding of principles of
research, epidemiology and biostatistics
Evaluated 4 JC in Pretoria with Standard Questionnaire - relating to
specific articles
Mean scores = 42%, 28%, 25%, 15 %
HOW WOULD WE SCORE?
Recommend a clearly defined curriculum teaching critical appraisal
skills, knowledge of basic epidemiology and biostatistics
Risk tolerance for the exclusion of potentially
life-threatening diseases in the ED
American Journal of Emergency Medicine (2007) 25, 540–544
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Objective: Given the same pretest probability (10%) for subarachnoid hemorrhage (SAH),
pulmonarymembolism (PE), and acute coronary syndrome (ACS), we determined if differences
exist in the risk tolerance for disease exclusion according to published guidelines given a negative
test result.
Methods: Published guidelines that make practice recommendations on the evaluation of ACS,
PE, and SAH were sought using the National Guideline Clearinghouse in low-risk settings.
Second-order Montem Carlo simulation was performed to determine point estimates and
confidence intervals (CIs) for posttest probabilities assuming a pretest probability of 10%.
Results: Guidelines recommend that patients with low-risk suspected ACS should undergo stress
testing. For SAH, computed tomography (CT) followed by lumbar puncture (LP) is recommended
without mention of pretest probability; and D-dimer testing is recommended to exclude PE in lowrisk patients. Test sensitivity for thallium-201 single photon emission computed tomography
(SPECT) was 89%, exercise echocardiogram was 85%, D-dimer testing was 95%, and CT/LP for
SAH was 100% (as a gold standard) and CT only was 97.5%. Given a negative test result, for PE,
posttest probability was 0.5% (95% CI 0.1%-0.9%); for SPECT, 1.1% (SD 0.5%-1.6%); and for
exercise echocardiogram, 1.5% (95% CI 0.5%-2.5%) compared with a posttest probability of 0%
for CT followed by LP for SAH. Using a CT-only approach gives a posttest probability of 0.2%
(95% CI 0.2%-0.4%).
Conclusions: Guidelines for suspected PE and ACS allow small but nonzero calculated risk end
points in low-risk settings, whereas SAH guidelines afford no misses. Because many gold
standard tests are more invasive and can have adverse effects, guideline authors should consider
adopting a standard acceptable miss rate as an end point for workups with low clinical suspicion
to avoid the overuse of invasive testing.
Risk Tolerance
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PE, ACS and SAH all have 10% pretest probability
Gold standard testing Pulmonary Angiography for PE,
Cardiac Catheterisation for ACS
CT Brain plus LP for SAH
Risk Tolerance =nonzero post test probability; level of uncertainty after diagnostic
testing that symptoms not due to disease
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Guidelines - PE = risk stratification, D-dimer, V/Q scan, CTPA
ACS = risk stratification,ECHO, SPECT
SAH = CT brain + LP
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Table 1 Expected posttest probabilities given negative testing at a pretest probability of 10%
Suspected disease/test
Posttest probability (95% CI)
SAH
CT followed by LP
0%
CT only
0.2% (0.0%-0.4%)
ACS
Exercise echocardiogram
1.5% (0.5%-2.5%)
Thallium-201 SPECT
1.1% (0.5%-1.6%)
PE
D-Dimer
0.5% (0.1%-0.9%)
Why are we willing to tolerate higher risks with ACS and PE?
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Frequency of presentation - familiarity breeds contempt
Higher clinical gestalt
Availability of Gold standard testing
Invasiveness and risks of invasive testing
Testing by ED staff only
Unable to risk stratify with SAH
Economic factors
Patient risk tolerance for investigation
Physician risk aversion
Test specificity- what to do with false positives
Problems - differences in sensitivity of CT with diff times and diff spectrum of
SAH
What is optimal risk tolerance for disease exclusion?
What is standard acceptable miss rate?
• Are Antibiotics Necessary After Incision and
Drainage of a Cutaneous Abscess?
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Annals of Emergency Medicine - Volume 50, Issue 1 (July 2007)
Our review of the literature found 5 studies and 1 abstract, spanning a 30-year period, which
address the issue of clinical outcomes of abscess incision and drainage with or without outpatient
oral antibiotics. Of the 3 randomized trials, 1 lacked a placebo group and was not blinded to either
the participants or the investigators; the 2 remaining studies, although double-blind placebocontrolled studies, used small study groups. None of the studies specifically addressed the issue of
abscesses with overlying cellulitis. Therefore, our conclusions cannot be extrapolated to those
cases in which there is a significant degree of overlying cellulitis. Although only 1 study excluded
patients with significant comorbidities and immunocompromised conditions, none of the other
studies specifically examined the impact of these comorbidities on clinical resolution. Finally, an
abscess was not explicitly defined in any of the studies.
Despite these limitations, each of the studies concluded that patients treated with incision and
drainage alone exhibit resolution of their infection at the same rate as patients who are treated with
incision and drainage plus antibiotic therapy. The data also demonstrate that both groups show a
greater than or equal to 90% frequency of full resolution without complications. Even when the data
from the most relevant and recent study are excluded because it is an abstract, the current
literature does not support the routine practice of prescribing antibiotics after incision and
drainage of simple cutaneous abscesses, even in high-MRSA-prevalence areas. A conclusive,
multicenter, double-blind, randomized, placebo-controlled clinical trial is lacking and sorely needed.
Antibiotics after Incision and Drainage
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1. Cephalosporin given - decreased recurrence in small RCT
2. No difference in RCT
3. No difference in RCT
4. Prospective - <5cms, children, including MRSA, incl
comorbidities
5. Large retrospective concordant vs discordant antibiotics, no
difference in resolution
Used clindamycin, different cephalosporins
Most excluded immunocompromised pts
Did not address issue of overlying cellulitis
Management of haemodynamically stable patients with abdominal stab
wounds Emergency Medicine Australasia (2007) 19, 269–275
Objectives: Australasian trauma centres receive relatively low numbers of penetrating injuries from
stabbings. There is limited agreement regarding protocols to guide the management of
haemodynamically stable patients with penetrating injuries. This has resulted in a wide
variation in practice with anecdotally high negative laparotomy rates. The aim of the
present study was to review the ED procedures, investigations and disposition of this
group of patients.
Methods: A retrospective review of all patients presenting with abdominal penetrating injury was
undertaken over a 5 year period. Data on demographics, presenting features and management
were collected.
Results: There were 109 patients who were haemodynamically stable (systolic blood pressure > 90)
on arrival to the trauma centre. Diagnostic ED procedures and investigations consisted of
wound exploration in 47 (43.1%) patients, focused abdominal sonography in trauma in 44
(40.4%) patients and a CT abdomen in 36 (33.0%) of patients. The sensitivity for focused
abdominal sonography in trauma and CT when used together was 77.8%. There were 39
laparotomies performed with a negative laparotomy rate of 23.1%. There were 10 laparoscopies
performed, none went on to require a laparotomy. Patients undergoing negative
laparotomies spent significantly longer times in hospital than patients managed conservatively
or those undergoing laparoscopies.
Conclusions: The number of penetrating abdominal injuries remains low. Imaging alone cannot reliably
exclude intraperitoneal injury. A greater utilization of ED wound exploration and laparoscopy
based on agreed guidelines could improve management. An algorithm for the management
of these patients is suggested.
Stable Abdominal stabs
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109 pts over 5 years - ? Major trauma centre
Stable - SBP> 90mmHg
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Wound exploration = 47 (36 repaired in ED, 2 + laps, 2 - laps, 3 lap scopes, 4 conservative Mx after CT)
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No wound exploration = 62 (34 laps 6-)
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Wound exploration techniques techniques described in J of E. medicine 1985
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In SA - high incidence
few adjunctive tests
laparotomy vs lap scope
Need for further studies
Do Children Require ECG Evaluation and Inpatient
Telemetry
After Household Electrical Exposures?
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[Ann Emerg Med. 2007;49:64-67.]
7 studies –all retrospective reviews 5-164 pts (less than 21 yrs)
• THE BOTTOM LINE
• Healthy children exposed to common household currents
• (120 to 240 V, no water contact), if asymptomatic at ED
• presentation and without a ventricular arrhythmia or cardiac
• arrest in the field, are at very low risk for developing cardiac
• arrhythmias. Patients with a normal initial ECG result do not
• develop late dysrhythmias, and those with nonfatal arrhythmias
• or nonspecific ECG abnormalities typically resolve
• spontaneously within 24 hours. Therefore, this review of
• available literature supports the practice of safely discharging
• these children without an initial ECG evaluation or inpatient
• cardiac monitoring after a common household current exposure.
• Our recommendations do not pertain to patients who might
• require admission for other injuries.
• The value of serum tau protein for the diagnosis of
intracranial injury in minor head trauma American Journal of
Emergency Medicine (2007) 25, 391–395
Abstract
Objective: Tau protein localizes in the axons of neuron cells, and it is released secondarily
from the central nervous system because of hypoxia and trauma. In the present study, it was
aimed to investigate the value of serum tau protein levels in diagnosing intracranial
pathologies in minor head trauma.
Methods: Patients were categorized into 2 groups: those without intracranial lesions in head
CTs (group1) and those with lesions in head CTs (group 2). Serum tau protein levels were
determined.
Results: Group 1 (n = 55) median serum tau protein level was 16.29 pg/mL (2.12-215.97
pg/mL) and group 2 (n = 33) median serum tau protein level was 18.39 pg/mL (2.19-714.47
pg/mL). Statistical analysis revealed no significant difference between the 2 groups for tau
protein values, sex, age, mechanism of trauma, and Glasgow Coma Scale score.
Conclusion: It is suggested that serum tau protein has limited value in minor head
trauma.
• Angiotensin II Receptor Blocker-Associated
Angioedema: On the Heels of ACE Inhibitor
Angioedema
Abstract
Angioedema and cough are known side effects of angiotensin-converting enzyme (ACE)
inhibitors. Angiotensin-converting enzyme is a potent inhibitor of kinase II, which facilitates
the breakdown of bradykinin. An increase in bradykinin levels results in continued
prostaglandin E2 synthesis, vasodilation, increased vascular permeability, and increased
interstitial fluid. In contrast, the angiotensin II receptor blockers (ARBs) do not increase
bradykinin levels. Angioedema as a complication of ACE inhibitor therapy is not widely
recognized; this complication is even less recognized with second-line ARBs. We report
angioedema associated with losartan (an ARB) in a patient who had experienced
angioedema secondary to enalapril (an ACE inhibitor). Almost half of patients with ARBassociated angioedema also had developed angioedema while receiving ACE inhibitor
therapy. Clinicians should exercise caution when using ARBs in patients with a history of
angioedema secondary to ACE inhibitors.
ARBs and Angiodema
Can angiotensin receptor antagonists be used safely in patients with previous
ACE inhibitor-induced angioedema?
Drug Saf. 2002;25(2):73-6
Angioedema is an uncommon but potentially life-threatening adverse event associated
with ACE inhibitor therapy which is believed to be due to potentiation of the vascular
effects of bradykinin. Angiotensin receptor antagonists were not expected to produce
angioedema, as they do not inhibit the catabolism of bradykinin. However, it is now
apparent that angioedema is occasionally associated with angiotensin receptor
antagonist therapy and may be more likely to occur in patients who have previously
experienced angioedema while receiving ACE inhibitors. Angiotensin receptor
antagonists cannot be considered to be a safe alternative therapy in patients who
have previously experienced ACE inhibitor-associated angioedema.
[Ann
Emerg
Med.
2007;49:717.]
A 19-year-old unrestrained male driver was being pursued by police and struck a telephone pole at a high rate of
speed. A 20-minute foot chase ensued. Once apprehended, he complained of back pain, was pale, was diaphoretic,
and
had
1
episode
of
bloody
emesis.
On physical examination, he had a respiratory rate of 16 breaths/min, pulse rate of 86 beats/min, blood pressure of
134/76, and oxygen saturation of 98% on a nonrebreather facemask. He was uncooperative and agitated and
complained only of back pain. On auscultation of his chest, his breath sounds were clear bilaterally. He had midthoracic
spine tenderness and diffuse abdominal tenderness to palpation. A supine chest radiograph (Figure 1) was performed
• IMAGES IN EMERGENCY MEDICINE
• DIAGNOSIS:
• Deep sulcus sign. First described by Gordon, the deep sulcus sign
may be the only evidence of a pneumothorax on a supine chest
radiograph. A deepening of the costophrenic angle occurs when air
tracks anteriorly and caudally along the pleural space when the
patient is lying supine.
• The arrows in Figure 2 highlight the hyperlucent area that is shown
as an anterior pneumothorax, which is revealed in Figure 3, the
computed tomography scan of the chest obtained immediately after
the chest radiograph.
• Figure 4 shows that the findings resolved after placement
• of the chest tube.
• False-positive examples of the deep sulcus sign have been
described in patients with chronic obstructive pulmonary disease
and those receiving mechanical ventilation with high tidal volumes.
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REFERENCES
1. Gorden R. The deep sulcus sign. Radiology. 1980;136:25-27.
2. Kong A. The deep sulcus sign. Radiology. 2003;228:415-416.
3. Tocino I, Armstrong JD. Trauma to the lung. In: Imaging of Diseases of the
Chest. St. Louis, MO: Mosby; 2000:770-771.
THE END