From the 2010 LLSA Reading List
Thomsen TW, et al
N Engl J Med
This article from the New England Journal of Medicine Clinical Video Series reviews the indications for paracentesis: to evaluate new-onset ascites and to rule out spontaneous bacterial peritonitis (SBP). SBP is a common, sometimes life-threatening infection that should be suspected in patients with ascites and associated symptoms such as fever, abdominal pain, worsening encephalopathy or renal function, leukocystosis, acidosis, gastrointestinal bleeding, sepsis, or shock. (Clin Liver Dis 2005;9:715.) Large-volume paracentesis may alleviate abdominal discomfort or respiratory distress in patients with tense ascites.
The authors confirm the extremely low incidence of significant bleeding complications associated with paracentesis despite concomitant coagulopathy or thrombocytopenia often present in these patients. A large series reported severe hemorrhage in only 0.2 percent of 4,500 paracenteses performed. (Transfusion 1991;31:164.) Although not specific, the authors do recommend observing patients with markedly increased creatinine for an extended period post-paracentesis because of a higher risk of bleeding complications. Paracentesis should be done with caution in patients with pregnancy, organomegaly, bowel obstruction, intra-abdominal adhesions, or a distended urinary bladder, and it should be avoided in patients with disseminated intravascular coagulation. Ultrasound guidance minimizes the risk of iatrogenic complications from paracentesis. Care also should be taken to avoid passing through sites of infection, engorged vessels, surgical scars, or abdominal-wall hematomas.
Aspirated fluid should be placed in containers, and sent for analysis as soon as possible. Early on, SBP is suggested by the presence of a polymorphonuclear (PMN) cell count greater than 250 cells/mm3 in the absence of an alternative source of infection. SBP is confirmed by ascites culture. The serum ascites to albumin gradient (SAAG) can help determine the cause where the etiology is uncertain. The SAAG is calculated by subtracting the albumin concentration in the ascites fluid from the concurrently measured serum albumin. If the SAAG is greater than or equal to 1.1 g/dl, it indicates the ascites is associated with portal hypertension. A SAAG less than 1.1 g/dl indicates ascites is not associated with portal hypertension. (Clin Liver Dis 2005;9:715.)
Complications include persistent ascites leakage, localized skin infection, and abdominal-wall hematomas. Rare serious complications include life-threatening hemorrhage and intra-abdominal organ injury. The authors also review complications specific to large-volume paracentesis such as hypotension, hyponatremia, and rarely, hepatorenal syndrome and death. The use of albumin as a plasma expander remains controversial due to high cost and lack of evidence showing survival benefit. Many experts, however, recommend its use for patients who have more than 5 liters of ascites fluid removed.
Comment: Paracentesis is frequently performed in the ED, and is generally safe in the hands of a seasoned physician. A few salient points should be emphasized, however.
The authors note that ascitic fluid can be localized by either exam or ultrasound, but in 2010, ultrasonographic-guided paracentesis should be the standard of care. Ultrasound is now ubiquitous in the emergency department, and paracentesis is one of the easiest indications of emergency bedside ultrasound to incorporate into clinical practice. Ultrasound has been shown to increase the success of paracentesis, and decrease complications. It allows differentiation of free intra-abdominal fluid from fluid-filled bowel loops, and can help maximize therapeutic benefit by allowing one to aim for the largest pocket of fluid. In a recent prospective randomized study, 95 percent of patients undergoing ultrasound-guided paracentesis had successful aspiration of ascites compared with only 61 percent of those undergoing the traditional approach. (Am J Emerg Med 2005;23: 363.)
The authors mention that some experts recommend all patients with ascites requiring hospitalization undergo surveillance paracentesis to evaluate for occult SBP. A recent study of emergency patients indicates that occult SBP is not uncommon. (Ann Emerg Med 2008;52:268.) This prospective, observational study found that physician clinical impression for detecting SBP had a sensitivity of only 76%, suggesting that all patients undergoing ED-performed paracentesis, even if only for therapeutic reasons, should have ascitic fluid sent to the laboratory to rule out occult SBP. The authors recommend that patients with SBP receive appropriate antibiotics and intravenous albumin. Albumin therapy can be expensive, however, and no large randomized control trials show any mortality benefit from albumin therapy for SBP.
From the 2010 LLSA Reading List
Assessment of Patient's Competence to Consent to Treatment
N Engl J Med
This article from the clinical practice series in the New England Journal of Medicine reviews patients' competency to consent for treatment. The author notes that informed consent is valid because appropriate information is disclosed to a competent patient able to make a voluntary choice. An accurate assessment of competency is critical in balancing respect for a competent patient's autonomy and protection for a patient with cognitive impairment from a bad decision (or no decision at all). Although the author uses the term competence and capacity interchangeably, he clarifies that competence usually refers to legal judgments and capacity to clinical judgments.
Physicians are frequently unaware of a patient's incapacity for decision-making, and when incapacity is suspected, many physicians do not know what standards to apply when assessing capacity. Patients particularly at risk for incapacity are those with Alzheimer's disease and other forms of dementia. Psychiatric patients not aware of their illness and their need for treatment also have a high association with incapacity. (Br J Psychiatry 2005;187:379.)
The author recommends applying the legal criteria in a report endorsed by the President's Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research (“Making Health Care Decisions.” Washington, D.C.: U.S. Government Printing Office; 1982; http://bit.ly/HCdecisions.) The criteria for decision-making capacity include the ability to communicate a choice, to understand relevant information, to appreciate medical consequences of a decision, and to reason and deliberate about treatment options.
There is no brief neuropsychiatric screening that has yielded consistent findings of cognitive impairment. Although the Mini-Mental State Examination (MMSE) has been shown to correlate with clinical judgments of incapacity, there is no single score that is highly sensitive or specific for incompetence. (J Gen Intern Med 1999; 14:27; Neurology 2005;64:1027.) The MacArthur Competence Assessment Tool for Treatment also is widely used, and incorporates information specific to a given patient's decision-making situation. (Psychiatr Serv 1997;48:1415.)
The author said a physician's determination of incapacity should reflect societal and judicial judgments, and there is a presumption that the vast majority are capable of making their own decisions. Only patients in the very bottom end of the impairment curve should be considered to lack capacity. (Making Health Care Decisions  http://bit.ly/HCdecisions.)
Once a patient is determined to lack capacity, the physician should attempt to identify and treat any possible reversible causes of the impairment. If the patient continues to lack capacity despite treatment or urgent interventions are required, then the physician should seek out a family member or person specified in an advance directive. Many states have statutes indicating the order in which family members should be approached; generally, spouse, adult children, parent, sibling, other relative. In an emergency, a physician can provide appropriate care under the presumption that a reasonable person in that particular situation would have consented to such treatments. (Informed Consent: Legal theory and clinical practice. 2nd Ed. New York: Oxford University Press, 2001.)
Comment: Assessment of a patient's capacity to consent to treatment is an important legal and ethical matter in medicine. Capacity is usually not a concern in most patient encounters, but the physician should recognize certain patient populations in which capacity could be a problem.
In ED risk management, the concept of valid informed consent is central to mitigating risk. The need to formally assess capacity can be thought of as inversely proportionate to the degree of agreement with medical opinion. An option chosen by a patient that is largely disparate with medical recommendations is unexpected, carries a greater risk of harm, and necessitates a greater need for capacity assessment. (Emerg Med Clin North Am 2009;27:605.)
Accurate determination of incapacity can be a difficult task because no gold standard test is available. Studies have demonstrated difficulties with physician assessment when based on informal clinical impressions (J Am Med Dir Assoc 2005;6[3 Suppl]:S100), so one should have a low threshold to formally evaluate when there is any concern. This article correctly recommends a standardized, structured approach to capacity assessment, and offers a framework for capacity evaluation that the EP can perform quickly. Whether or not the patient agrees with medical recommendations, documenting the evaluation will likely serve to mitigate future risk.
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