What is the sensitivity of CT to determine appendicitis?

The Bottom Line: The diagnostic accuracy of noncontrast CT for the diagnosis of acute appendicitis in the adult population is adequate for clinical decision making.

Reference: Hlibczuk V, Dattaro JA, Jin Z, Falzon L, Brown MD.  Diagnostic accuracy of noncontrast computed tomography for appendicitis in adults: a systematic review.  Ann Emerg Med. 2010 Jan;55(1):51-59.

Summary: The search for this review yielded 1,258 publications; 7 studies met the inclusion criteria and provided a sample of 1,060 patients. The included studies were of high methodological quality with respect to appropriate patient spectrum and reference standard. The pooled estimates for sensitivity and specificity were 92.7% (95% confidence interval 89.5% to 95.0%) and 96.1% (95% confidence interval 94.2% to 97.5%), respectively; the positive likelihood ratio=24 and the negative likelihood ratio=0.08.

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For patients with gastrointestinal bleeding, how do you decide which patients to send to the floor & which to send to the ICU?

BLEED tool
Kollef MH, et al. BLEED: a classification tool to predict outcomes in patients with
acute upper and lower gastrointestinal hemorrhage. Crit Care Med. 1997 Jul;25(7):
1125-32.

  • B visualized red blood (hematemesis, nasogastric lavage, or per rectum other than clinically assessed self-limited hemorrhoidal bleeding)
  • L low systolic blood pressure (< 100 mm Hg)
  • E elevated prothrombin time (>1.2 times the control value)
  • E erratic mental status
  • D unstable comorbid disease (i.e., any condition normally requiring admission to ICU

465 patients admitted through ER for upper or lower GI bleeding.  Classified as high or low risk based on these criteria.  Results include risk of in-hospital complications for high and low risk patients.

Repost from 9/25/09

How can you assess respiratory muscle function at the bedside?

Bottom line:  Measuring maximum inspiratory pressure and maximum expiratory pressure can provide information on respiratory muscle weakness and can be used at the bedside for monitoring patients who may be at risk for respiratory failure.

Table 24-10. In:  Murray and Nadel’s Textbook of Respiratory Medicine, 5th ed.
Summarizes methods for assessing respiratory muscle weakness.  PImax (maximal inspiratory pressure) and PEmax (maximal expiratory pressure) are two tests that can be performed at the bedside  that can provide some information about muscle function, but they have poor positive predictive value.

Video of procedure for measuring negative inspiratory force, also known as maximum inspiratory pressure.

Maximal Inspiratory and Expiratory Pressures.  In:  Murray and Nadel’s Textbook of Respiratory Medicine, 5th ed.
Describes the procedure and how monitoring can be used to monitor patients with neuromuscular discorders, such as GBS, to identify development of respiratory failure.

What blood pressure goals are recommended for a patient with acute aortic dissection?

Bottom line:  Acute management includes blood pressure goal of < 120mm Hg systolic or lowest BP that maintains end organ perfusion.

Summary: Joint guidelines (ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM) on managing aortic dissection recommends goal of systolic BP < 120 mm Hg or lowest BP that maintains end organ perfusion during initial management.  For blood pressure control in ongoing medical management, guidelines recommend antihypertensive therapy to achieve a goal of less than 140/90 mm Hg (patients without diabetes) or less than 130/80 mm Hg (patients with diabetes or chronic renal disease) to reduce the risk of stroke, myocardial infarction, heart failure, and cardiovascular death.

Summary of treatment in Hypertensive Emergency article in DynaMed.  Briefly describes initial treatment in the setting of aortic dissection, including target systolic BP < 120 mm Hg within 5-10 minutes; usually requires beta blocker and vasodilator (vasodilator used without beta blocker increases risk of reflex tachycardia); options for beta blocker: esmolol or metoprolol; for vasodilator: nicardipine, nitroprusside, or fenoldopam.

How are aortic dissections classified?

Bottom line:  Aortic dissections are classified according to location, nature and extent of tear.  The Stanford system is widely used, and describes tears according to involvement of ascending aorta, regardless of the origin of the tear.

Summary Thoracic aortic aneurysm and dissection.  In:  DynaMed.
For brief description of classification systems, click on General>Types on the menu of the DynaMed article.
Stanford system categorizes dissections into Type A (involves ascending aorta) and Type B (does not involve ascending aorta. See Illustration for further sub-categories according to more specific location. The DeBakey system describes dissections according to the origin and extent of the tear. Dissections can also be described by timecourse to presentation (acute/sub-acute/chronic) and nature of the intimal tear (classical dissection w/double lumen separated by septum; intramural hematoma; intimal tear without medial hematoma; penetrating atherosclerotic ulcer usually to adventitia with localized hematoma or saccular aneurysm; iatrogenic or traumatic dissection

Joint guidelines (ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM) include a management algorithm (p. e71-e72) that includes pathways for Type A and Type B dissections.

How can bicarbonate be used in management of rhabdomyolysis?

Bottom line: Although there is no good evidence to support this strategy, bicarbonate is employed by some clinicians to force alkaline dieresis after initial resuscitation with saline.

Summary:  For an overview of current opinion, see Rhabdomyolysis in DynaMed (Treatment Section.)
Also, see Bench-to-bedside review: Rhabdomyolysis — an overview for clinicians. Crit Care. 2005 Apr;9(2):158-69.

What is the algorithm for early goal-directed therapy for patients in septic shock and does it reduce mortality?

Bottom line: Use of early goal-directed therapy for management of septic shock or severe sepsis can reduce in-hospital mortality.

Summary:  Rivers E, et al.  Early goal-directed therapy in the treatment of severe sepsis and septic shock.  N Engl J Med. 2001 Nov 8;345(19):1368-77.

View the algorithm for early goal-directed therapy
263 patients with severe sepsis or septic shock randomized to 6 hours of early goal-directed therapy vs. standard therapy prior to admission to ICU.  Goal-directed therapy included
    • CVC  that measured CV oxygen sat
    • crystalloid 500 mg every 30 minutes as needed to maintain central venous pressure 8-12 mm Hg
    • vasoactive agents as needed to maintain mean arterial pressure 65-90 mm Hg
    • transfusion of red cells to hematocrit > 30%
    • inotropic agents as needed to maintain central venous oxygen saturation > 70%
RESULTS:  In-hospital mortality was 30.5% with early goal-directed therapy vs. 46.5% with standard therapy (NNT=7)

For which conditions are anticonvulsants typically prescribed?

Bottom line: Antiepileptic drugs (AEDs) are used in the setting of traumatic brain injury and intracerebral hemorrhage. Prophylactic AEDs for these indications are recommended by Brain Trauma Foundation and American Heart Association, respectively, although there is no strong evidence for benefit in the setting of intracerebral hemorrhage. 
Summary: For traumatic brain injury, there is evidence for up to 1 week use to prevent early post-traumatic seizures. Use with patients with aneurysmal subarachnoid hemorrhage and ichemic stroke is controversial with no evidence of benefit from prospective randomized trials. Other conditions for which there is demonstrated risk of seizures for which there is no evidence of efficacy of prophylactic AEDs include brain tumors, cerebral venous and sinus thrombosis and herpes simplex encephalitis.
Liu KC, Bhardwaj A. Use of Prophylactic Anticonvulsants in Neurologic Critical Care: A Critical Appraisal. Neurocritical care. 2007; 7(2): 175-184.

Repost of August 24, 2010

Evidence on physical capability and mortality, early use of palliative care, and tools for assessing delirium in ICU patients

Objectively measured physical capability levels and mortality: systematic review and meta-analysis. BMJ. 2010 Sep 9;341:c4467. doi: 10.1136/bmj.c4467.
Systematic review of studies on association of various measures of physical activity and mortality in community populations

Early palliative care for patients with metastatic non-small-cell lung cancer.  N Engl J Med. 2010 Aug 19;363(8):733-42.
RCT of patients with newly diagnosed non-small-cell lung cancer to receive standard care plus early palliative care or standard care alone.

Different assessment tools for intensive care unit delirium: which score to use? Crit Care Med. 2010 Feb;38(2):409-18.
Study comparing three instruments for assessing delirium in ICU patients.

Which patients should receive intravenous PPI therapy?

Bottom line:  In patients with nonvariceal upper gastrointestinal bleeding, intravenous PPIs should be used after successful endoscopic therapy in patients with high-risk stigmata (active bleeding, visible vessel, adherent clot.)
Summary: Dynamed cites evidence from International Consensus Recommendations on the Management of Patients With Nonvariceal Upper Gastrointestinal Bleeding.  Ann Intern Med.  2010; 152(2): 101-13. A systematic review of the literature revealed 6 RCTs (2223 patients) that included 5 studies that assessed intravenous PPIs.  See details of the meta-analysis under Statement A8 of this appendix.