Primecuts – This Week In The Journals

April 19, 2016


curryBy B. Corbett Walsh, MD 

Peer Reviewed

As many of us reflect on the Democratic Presidential Debate held this past Thursday in our backyard in Brooklyn, we prepare for the New York Primary scheduled for this Tuesday, April 19th. Across the coast, the Golden State Warriors broke the Chicago Bulls 1995-96 NBA record by having the most wins in any regular season, finishing 73-9. On that same night, Kobe Bryant retired from the Los Angeles Lakers after an illustrious 20-year professional NBA career resulting in 5 Championship titles. As votes are decided, records broken, and legends retire, we turn now to key medical news in this week’s Primecuts.

Do we still need Chest X-Ray after an ultrasound guided right internal jugular central line? [1]

Placement of central venous lines is a common procedure performed on critically ill patients to administer lifesaving medications. It is standard practice to obtain a chest x-ray post-procedure to ensure appropriate placement and assess for complications. However, a new study published in Critical Care Medicine challenges the need for routine chest x-rays to confirm placement. The study authors retrospectively chart reviewed 1322 right IJ central lines that were placed under ultrasound guidance in emergency departments, ICUs, and general wards at an academic tertiary hospital system. Procedures were performed by resident physicians and attending physicians in various specialties including critical care medicine, emergency medicine, anesthesia, internal medicine, and general surgery. Residents and fellows performed the majority of lines (75%), while interns performed 12%. Chest radiographs were obtained post-procedure to assess for misplacement (defined as any catheter tip position that was not in the SVC to upper RA confluence) and the presence of pneumothorax. The overall rate of success of ultrasound-guided right internal jugular vein central venous line placement was 96.9%, with 79% accomplished during the first attempt. Complications were limited to only one pneumothorax (0.1% [95% CI, 0–0.4%]), and the rate of catheter misplacement requiring repositioning or replacement was 1.0% (95% CI, 0.6–1.7%). Multivariate regression analysis showed no correlation between high-risk patient characteristics and composite complication rate. The authors note that routine chest radiograph after this common procedure is an unnecessary use of resources (costing approximately $200[2-3]) and may delay resuscitation of critically ill patients.

FDA revises warnings regarding the use of metformin for type 2 diabetes in certain patients with reduced kidney function [4]

In 2012, 29.1 million Americans were diagnosed with diabetes, with approximately 1.4 million new diagnosed each year.[5] Metformin is typically the first pharmacologic agent used when behavior modification for type-two diabetes has failed. Indeed, approximately 14.4 million patients received a prescription for metformin in 2014.[6] The FDA, however, has restricted its use in patients with kidney disease as the medication is renally cleared and may increase the risk of lactic acidosis. As these concerns have not been evident in the medical literature, the FDA conducted a literature review and has now revised its recommendations as below.

  • Before starting a patient on metformin and at least annually thereafter, obtain the patient’s estimated glomerular filtration rate (eGFR). Patients with other risk factors for kidney disease, such as advanced age, should have their eGFRs checked more frequently.
  • Metformin is contraindicated in patients with an eGFR below 30 mL/minute/1.73 m2 and shouldn’t be initiated in eGFRs of 30–45 mL/minute/1.73 m2. For patients whose eGFR declines into the 30–45 mL range while on treatment, clinicians should assess risks and benefits before continuing.
  • Metformin should be stopped at or before an iodinated contrast imaging procedure in patients whose eGFR is 30–60 mL/minute/1.73 m2; in those with a history of liver disease, alcoholism, or heart failure; or in those who will be given intra-arterial iodinated contrast. [7-10]

This will likely shift the focus towards using a patient’s calculated GFR rather than their serum creatinine to decide on the safety of using metformin, potentially allowing more patients to use and benefit from the medication.

Is it Ethical to Withhold Prevention? [11]

In a Perspective piece featured in the most recent issue of the New England Journal of Medicine, Dr. Thomas Farley describes how the medical profession conceptualizes the provision of highly advanced, often costly, medical care, but refrains from providing public health measures even when they are effective and low in cost. The author proposes two commonly encountered cases; an elderly woman with metastatic lung cancer who could undergo radiation & chemotherapy that might extend her life for a few months at a cost of over $100,000, or a proposal to help smokers quit smoking (and thereby reduce the incidence of lung cancer). The first case places emphasis on the value of extending human life while the second on the cost of the intervention. Dr. Farley points out that both scenarios expose complicated issues of ethics, cost, and cost-effectiveness and highlight a troubling structural bias against prevention inherent in the medical industry. The author notes two contrasting themes driving medical care between the two cases. The first is the nature of the patient. The woman with lung cancer will receive treatment regardless of cost because she is a human being with a name and a face with whom we can empathize, and whose suffering from lack of treatment we can see tangibly. The public health campaign, in contrast, prevents suffering in people who are unnamed and unseen, and thus easier to ignore. The second point is the manner in which our society pays for medical care. The woman receives treatment because as a society, we reimburse hospitals and doctors for the costs of her care (with government funding of uncompensated care). In contrast, we finance most primary preventive services through budgets for public health agencies, which are subject to fixed annual appropriations and must compete with budgets for schools, police, and other public needs. Recognizing that our ethical frameworks for weighing costs in the two scenarios are inconsistent is an important step in addressing what Dr. Farley calls “a systematic bias against prevention”.

Is Thrombocytopenia an Early Prognostic Marker in Septic Shock? [12]

Earlier this year, the sepsis guidelines were updated to take into account the latest understanding of its fundamental pathophysiology, abandoning the old SIRS criteria in favor of the “sepsis related organ failure score” (SOFA). One element of the SOFA score is platelet count, which is based on the belief that thrombocytopenia is indicative of the severity of illness in the patient. [13] In the latest issue of Critical Care Medicine, Thiery-Antier et al. designed a prospective multicenter observational cohort study at academic hospitals to assess if early thrombocytopenia during septic shock was associated with an increased risk of death at day 28 and to evaluate the risk factors associated with low platelet count. Of the 1486 patients studied, simplified Acute Physiology Score II score of greater than or equal to 56, immunosuppression, age of more than 65 years, cirrhosis, bacteremia (p ≤ 0.001 for each), and urinary sepsis (p = 0.005) were globally associated with an increased risk of thrombocytopenia within the first 24 hours following the onset of septic shock. Additionally, a platelet count of less than or equal to 100,000/mm3 was independently associated with a significantly increased risk of death within the 28 days following the onset of septic shock. The risk of death increased with the severity of thrombocytopenia (hazard ratio, 1.65; 95% CI, 1.31–2.08 for a platelet count below 50,000/mm3 vs > 150,000/mm3; p < 0.0001). Therefore, measuring platelet count can serve as a simple way for physicians to determine a prognosis for patients or their families if they are admitted to an ICU with septic shock. Also in the news, Among patients with AF with a single additional stroke risk factor (CHA2DS2-VASc score = 1 in men, 2 in women), oral anticoagulation use was associated with an improved prognosis for stroke/systemic thromboembolism/death. [14] The U.S. Preventive Services Task Force updates its 2007 and 2009 recommendations regarding aspirin for primary prevention of cardiovascular disease and colorectal cancer in some high-risk adults in their 50s and 60s. Low-dose aspirin is now recommended for adults aged 50–59 who have at least a 10% risk for a cardiovascular event in the next decade, low bleeding risk, and a life expectancy of at least 10 years; patients must also be willing to take aspirin daily for at least 10 years (grade B recommendation). [15] The CDC announced the first male-to-male sexual transmission of the Zika Virus.[16] Previously there had been one prior case report of a sexual transmission via vaginal intercourse.

Dr. B. Corbett Walsh is a medical intern at NYU Langone Medical Center 

Peer reviewed by Amar Parikh, MD, 2nd year medicine resident at NYU Langone Medical Center  

Image courtesy of The Associated Press

References:

[1] Hourmozdi JJ1, Markin A, Johnson B, Fleming PR, Miller JB. Routine Chest Radiography Is Not Necessary After Ultrasound-Guided Right Internal Jugular Vein Catheterization. Crit Care Med. 2016

[2] Pikwer A, Bååth L, Perstoft I, et al: Routine chest x-ray is not required after a low-risk central venous cannulation. Acta Anaesthesiol Scand 2009; 53:1145–1152 8.

[3] Lessnau KD: Is chest radiography necessary after uncomplicated insertion of a triple-lumen catheter in the right internal jugular vein, using the anterior approach? Chest 2005; 127:220–223

[4] http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm494829.htm

[5] http://www.diabetes.org/diabetes-basics/statistics/

[6] http://www.fda.gov/Drugs/DrugSafety/ucm493244.htm

[7] Rachmani R, Slavachevski I, Levi Z, Zadok B, Kedar Y, Ravid M. Metformin in patients with type 2 diabetes mellitus: reconsideration of traditional contraindications. Eur J Intern Med 2002;13:428.

[8] Kamber N, Davis WA, Bruce DG, Davis TM. Metformin and lactic acidosis in an Australian community setting: the Fremantle Diabetes Study. Med J Aust 2008;188:446-9.

[9] Roussel R1, Travert F, Pasquet B, Wilson PW, Smith SC Jr, Goto S, et al. Metformin use and mortality among patients with diabetes and atherothrombosis. Arch Intern Med 2010;170:1892-9.

[10] Ekström N, Schiöler L, Svensson AM, Eeg-Olofsson K, Miao Jonasson J, Zethelius B, et al. Effectiveness and safety of metformin in 51 675 patients with type 2 diabetes and different levels of renal function: a cohort study from the Swedish National Diabetes Register. BMJ Open 2012;2.pii:e001076

[11] Farley TA. When Is It Ethical to Withhold Prevention? N Engl J Med. 2016 Apr 7;374(14):1303-6. https://www.ncbi.nlm.nih.gov/pubmed/?term=Farley+TA.+When+Is+It+Ethical+to+Withhold+Prevention%3F+N+Engl+J+Med.+2016+Apr+7%3B374(14)%3A1303-6.

[12] Thiery-Antier N, Binquet C, Vinault S, Meziani F, Boisramé-Helms J, Quenot JP; EPIdemiology of Septic Shock Group. Is Thrombocytopenia an Early Prognostic Marker in Septic Shock? Crit Care Med. 2016 Apr;44(4):764-72.

[13] Singer M, Deutschman CS, Seymour CW, Shankar-Hari M, Annane D5, Bauer M, Bellomo R, Bernard GR, Chiche JD, Coopersmith CM, Hotchkiss RS, Levy MM, Marshall JC, Martin GS, Opal SM, Rubenfeld GD, van der Poll T, Vincent JL, Angus DC. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016 Feb 23;315(8):801-10.

[14] Fauchier L, Lecoq C, Clementy N, Bernard A, Angoulvant D, Ivanes F, Babuty D, Lip GY.Oral Anticoagulation and the Risk of Stroke or Death in Patients With Atrial Fibrillation and One Additional Stroke Risk Factor: The Loire Valley Atrial Fibrillation Project. Chest. 2016 Apr;149(4):960-8.

[15] Bibbins-Domingo K; U.S. Preventive Services Task Force. Aspirin Use for the Primary Prevention of Cardiovascular Disease and Colorectal Cancer: U.S. Preventive Services Task Force Recommendation Statement. Ann Intern Med. 2016 Apr 12.

[16] D. Trew Deckard, PA-C; Wendy M. Chung, MD; John T. Brooks, MD; Jessica C. Smith, MPH Senait Woldai, MPH; Morgan Hennessey, DVM; Natalie Kwit, DVM; Paul Mead, MD. Morbidity and Mortality Weekly Report (MMWR): Male-to-Male Sexual Transmission of Zika Virus. Weekly / April 15, 2016 / 65(14);372–374