Ultrasound machine number 3 had MRSA contaminate the probe handle before through cleaning.

Our study was conducted at a single urban teaching hospital, which may not be representative of MRSA and other pathogens in the community. In addition, swabs were obtained at random and on 3 separate dates. To minimize those effects, we collected samples at different times of the day. To eliminate variations in sample gathering, the same 2 individuals performed all sample collections. All cultures were processed in the same manner. We did not record several events such as the amount of times a particular ultrasound machine was used, the type of study conducted, and if it was cleaned. These events could affect the results of this study.

We expected increased use of ultrasound because the MRSA study required each abscess to be imaged. As a result, cleaning patterns might have changed. But our findings did not show increased MRSA growth as we anticipated. This does not reflect the increased prevalence of MRSA skin infections treated in EDs [2-5]. These findings were somewhat surprising because ultrasound machines were being used more frequently than usual for abscess assessment. On the other hand, no studies have reliably demonstrated the life span of MRSA on inanimate objects in the ED [3].

Our study indicates that bacterial pathogen growth on ED ultrasound machines is quite common. bacterial pathogens began to contaminate the machines 1 week after the initial cleaning. Almost all cultured sites grew some type of bacterial pathogen by the last culture, which raises concerns regarding Infection control in the ED. This indicates that ultrasound users are not using proper cleaning techniques. Clinicians must be vigilant to clean not only the transducer but also all areas of the equipment to decrease the spread of infection among patients. Guidelines for proper ultrasound machine cleaning should be developed to minimize cross contamination between patients.

Acknowledgments

The authors wish to thank Cheri Pantoja for her assistance with this project.

Gibrham Rodriguez MD

Dan Quan DO Department of Emergency Medicine Maricopa Medical Center

Phoenix, AZ 85008 E-mail address: [email protected]

doi:10.1016/j.ajem.2011.03.009

References

1. Kuo DC, Chasm RM, Witting MD. Emergency department physician ability to predict methicillin-resistant Staphylococcus aureus skin and soft tissue infections. J Emerg Med 2010;39(1):17-20.
2. Frazee BW, Lynn J, Charlebois ED, Lambert L, Lowery D. Perdreau- RemingtonF. High prevalence of methicillin resistant Staphylococcus aureus in emergency department skin and soft tissue infections. Ann Emerg Med 2005;45(3):311-20.
3. Kei J, Richards JR. The prevalence of methicillin resistant Staphylo- coccusAureus on inanimate objects in an urban emergency department. J Emerg Med 2008:24.
4. Shukla SK. Community-associated methicillin resistant Staphylococcus aureus and its emerging virulence. Clin Med Res 2005;3(2):57-60.
5. Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft-tissue infections. Clin Infect Dis 2005;41(10):1373-406.

Do we need echocardiography before commencing thrombolytic therapy also for pulmonary embolism?

To the Editor,

We read with great interest the letter by Dr Hasanin and Kinsara [1] in the February 2011 issue of the American Journal of Emergency Medicine, in which they described a case of fatal multiple infarcts 1 hour after initiation of thrombolytic therapy for acute ST-elevation myocardial infarction [1]. In their case report, echocardiography study disclosed a dilated left ventricle with severe global hypokin- esis suggestive of preexisting cardiomyopathy and a disintegrated Left ventricular apical thrombus pointing out to the source of the embolic complications. The authors raise the question whether echocardiography before initiating thrombolytic therapy would affect the decision of commenc- ing thrombolytic therapy and help avoiding complications.

Besides myocardial infarction, thrombolytic therapy is also indicated in patients with pulmonary embolism (PE) present- ing with hemodynamic instability, unless there are major contraindications owing to bleeding risk [2-3]. Furthermore, thrombolytic therapy may be indicated in selected patients with PE and right ventricular dysfunction. In any case, thrombolytic therapy must be avoided in patients without right ventricular dysfunction in consideration of scarce safety and effectiveness in these cases. We present a case of a patient presenting with shock in the emergency department (ED) and diagnosed with massive PE. An emergency ultrasound (US) examination excluded the presence of acute right ventricular dysfunction and allowed to avoid thrombolytic therapy and to perform appropriate therapy.

A 60-year-old woman presented to the ED because of malaise, oliguria, and dyspnea. Her medical history included hypertension, severe obesity, rheumatoid arthritis managed with long-term steroidal therapy, obstructive Sleep apnea syndrome requiring continuous positive airways pressure treatment, hypothyroidism treated with levothyroxine, and previous episodes of urinary tract infection and deep venous thrombosis. She had impaired mobility due to obesity and Musculoskeletal pain.

On arrival, the patient appeared in acute distress. On physical examination, the temperature was normal, blood

pressure was 80/50 mmHg, the pulse had a regular rhythm with a rate of 120 beats per minute, and the percutaneous peripheral oxygen saturation was 90% on air; lower extremities appeared cool and edematous, whereas the remainder of the examination was normal. The electrocar- diogram confirmed the presence of sinusal rhythm with no signs of Ischemic injury. Blood tests yielded leucocytosis, renal failure, and increased D-dimer levels. A chest computed tomography scan was obtained and showed the presence of massive PE. Saline solution was rapidly administered intravenously and the patient was quickly transferred in our unit to perform thrombolytic therapy. On arrival, the patient appeared in shock, notwithstanding a large amount of fluid had been administered. A bedside US examination was performed by the emergency physician. US disclosed a normokinetic and not dilated right ventricle and an inferior vena cava with small diameter collapsing completely during inspiration; left ventricle resulted mildly dilated, hypertro- phic, and hyperkinetic. In consideration of these findings, thrombolytic therapy was avoided and the patient underwent further fluid resuscitation and noradrenaline intravenous infusion after central venous catheter positioning. In the meanwhile, Urine analysis showed signs of urinary tract infection and antibiotic was started. Over the following days, the patient’s condition gradually improved and urine culture detected the presence of Escherichia coli. Noradrenaline was stopped on the third day, and antibiotic continued for 10 days. The patient was discharged without complications. PE is a common clinical diagnosis with different clinical presentations in ED. PE with hemodynamic instability is a life-threatening event requiring thrombolytic therapy. Obstruction of pulmonary arteries induces an increase of right ventricular afterload entailing right ventricular dys- function. The decreased right ventricular output reduces left ventricular preload and cardiac output causing hypotension and shock. US can easily detect the right ventricular dysfunction showing right ventricular enlargement, free wall hypokinesis with sparing of the apex, paradoxical septal motion, and inferior vein cava dilation without physiologic inspiratory collapse [4]. In patients with PE and normal hemodynamic parameters, US helps distinguish between subjects with intermediate and low risk. In patients with PE presenting with shock, the absence of echocardiographic signs of right ventricular dysfunction excludes PE as a cause of hemodynamic instability. In these patients, avoiding thrombolytic therapy and searching for alternative causes of shock are mandatory. US appears to be a useful tool in differential diagnosis of shock disclosing signs of cardiac tamponade, left ventricular hypokinesis, acute valvular

dysfunction, and hypovolemia.

In our case, the patient was diagnosed with PE but no echocardiographic signs of obstructive shock were discov- ered. On the contrary, US showed normal right ventricular dimensions and kinesis and normal left ventricular systolic function and signs of hypovolemia. A diagnosis of septic shock was made in consideration of history, clinical and US

findings, and the patient was correctly managed with aggressive hemodynamic approach and antibiotic therapy.

Determining the correct etiology and management of shock in ED patients is challenging. History and clinical findings may be scarce or misleading. Otherwise, emer- gency physicians are asked to take weighty decisions in a short time. Ultrasound is a goal-directed, rapid, and bedside technology widely available in ED and being able to resolve complicated clinical situations. As suggested by Hasanin and Kinsara [1], we pose the question whether US before initiating high-risk treatment (especially thrombolytic therapy) would affect the patient management and help avoiding complications.

Fabrizio Elia MD Giovanni Ferrari MD Franco Apra MD

high dependency unit San Giovanni Bosco Hospital Piazza Donatore del Sangue 3

10154 Torino, Italy E-mail addresses: [email protected] [email protected]

[email protected]

doi:10.1016/j.ajem.2011.03.021

References

1. Hasanin AM, Kinsara AJ. Do we need echocardiography before commencing thrombolytic therapy? Am J Emerg Med 2011;29(240): e1-e3.
2. Torbicki A, Perrier A, Konstantinides S, Agnelli G, Galie N, Pruszczyk P, et al. Guidelines on the diagnosis and management of acute pulmonary embolism: the Task Force for the Diagnosis and Manage- ment of Acute Pulmonary Embolism of the European Society of Cardiology (ESC). Eur Heart J 2008;29:2276-315.
3. Hirsh J, Guyatt G, Albers GW, Harrington R, Schunemann HJ. Antithrombotic and thrombolytic therapy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest 2008;133(6 Suppl):110S-2S.
4. Mookadam F, Jiamsripong P, Goel R, Warsame TA, Emani UR, Khandheria BK. Critical appraisal on the utility of echocardiography in the management of acute pulmonary embolism. Cardiol Rev 2010;18: 29-37.

Ondansetron as an effective antiemetic in the rural, out-of-hospital setting

To the Editor,

We write to you with the results of our investigation of ondansetron as an acceptable and efficacious antiemetic for the treatment of nausea and vomiting in the rural, out-of- hospital setting. Nausea is a commonly encountered patient complaint in both the out-of-hospital and emergency department (ED) settings [1]. Although a nonspecific