UMEM Educational Pearls - Critical Care

Question

In a study of alarms from 77 monitored ICU beds over the course of a month at the University of California, San Francisco, false alarms were common. Accellerated Ventircular Rhythms (AVRs) made up roughly one third of the alarms, and of the more than 4,361 AVRs, 94.9% were false while the remaining 5.1% did not result in a clinical action.

While this study had a majority of patients in the Med/Surg ICUs, a minority were from the cardiac and neurologic ICUs giving it some broad applicability. This study adds to the literature indicating there are subsets of alarms which may not be necessary or which may require adjustment to increase specificity.

Suba S, Sandoval CS, Zegre-Hemsey J, et al. Contribution of Electrocardiographic Accelerated Ventricular Rhythm Alarms to Alarm Fatigue. American Journal of Critical Care. 2019; 28(3):222-229

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Question

Don’t miss the injecting drug users with botulism!

Wound botulism presents as descending paralysis when Clostridium botulinum spores germinate in anaerobic necrotic tissue. There have been hundreds of cases in the last decade, but it is poorly reported outside of California.

Black tar heroin and subcutaneous injection (“skin popping”) carry the highest risk, but other injected drugs and other types of drug use suffice. C botulinum spores are viable unless cooked at or above 85°C for 5 minutes or longer and this is not achieved when cooking drugs. 

Early administration of botulism anti-toxin (BAT) not only saves lives but can prevent paralysis and mechanical ventilation. An outbreak of 9 cases between September 2017 and April 2018 cost roughly $2.3 million, in part because patients didn’t present on average until 48 hours after symptom onset and it took an additional 2-4 days before the true cause of their respiratory depression and lethargy were understood. One patient died.

PEARL: talk to your injecting drug users about the symptoms of botulism: muscle weakness, difficulty swallowing, blurred vision, drooping eyelids, slurred speech, loss of facial expression, descending paralysis, and difficulty breathing. Consider botulism early in your patients who inject drugs but who do not respond to naloxone or who exhibit prolonged symptoms. Testing at the health department is performed with mouse antibodies to Botulism Neurotoxin (BoNT) combined with the patient’s serum.

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Torsades de pointes and QT prolongation Associated with Antibiotics

Methods

The authors queried the United States FDA Adverse Event Reporting System (FAERS) from 01/01/2015 to 12/31/2017 for reports of Torsade de points/QT prolongation (TdP/QT).

Reporting Odd Ratio (ROR) was calculated as the ratio of the odds of reporting TdP/QTP versus all other ADRs for a given drug, compared with these reporting odds for all other drugs present in FAERS

Results

FAERS contained 2,042,801 reports from January 1, 2015 to December 31, 2017. There were 3,960 TdP/QTP reports from the study period (0.19%).

Macrolides               ROR 14 (95% CI 11.8-17.38)

Linezolid                  ROR 12 (95% CI 8.5-18)

Amikacin                 ROR 11.8 (5.57-24.97)

Imipenem-cilastatin ROR 6.6 (3.13-13.9)

Fluoroquinolones   ROR 5.68 (95% CI 4.78-6.76)

Limitations:

These adverse events are voluntary reports

There might be other confounded by concomitant drugs such as ondansetron, azole anti-fungals, antipsychotics.

Bottom Line:

This study confimed the previously-known antibiotics to be associated with Torsades de pointes and QT prolongation (Macrolides, Linezolid, Imipenem and Fluoroquinolones). However, this study  found new association between amikacin and Torsades de pointes/QT prolongation.

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Rapid Assessment of the RV on Bedside Echo

There are several causes of acute RV dysfunction resulting in a patient presenting to the ER with unstable hemodynamics. Some of these include acute cor pulmonale, acute right sided myocardial infarction and acute submassive or massive pulmonary embolism. While bedside assessment of the LV function is often performed by the ED physician, simultaneous evaluation of the RV can provide crucial information that can help guide therapeutic decisions to prevent worsening of the patient’s clinical condition. A rough guideline to determine RV size and function is below using the apical 4 chamber view.

Normal RV size :            <2/3 the size of the LV

Mildly enlarged RV :       >2/3 the size of the LV, but not equal in size

Moderately enlarged RV:  RV size = LV size

Severely enlarged RV:      RV size > LV size

Patients who are found to have RV dilation should be given fluids in a judicious fashion as the RV is not tolerant of fluid overload. Early diagnosis of the cause of acute RV failure should be sought to guide definitive therapy, but early institution of inotropic support should be considered. Frequent reassessments of biventricular function during resuscitation should be performed.

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Attachments

1911051940_Presentation2.pptx (178 Kb)

While chest X ray (CXR) is routinely obtained in the setting of traumatic injury, ultrasound (US) is a fast and reliable way to evaluate for life-threatening traumatic injuries requiring emergent intervention, and is supported by the Eastern Association for the Surgery of Trauma (EAST) guidelines. A recent Cochrane Review compared the test characteristics of chest US vs CXR for detection of traumatic pneumothorax when using Chest CT or thoracostomy as the gold standard.

• Primary end point: sensitivity and specificity for pneumothorax
• US performed by nonradiologists.
• 9 studies, 1271 patients, 410 of which had a pneumothorax
• Summary sensitivity: US 0.91 (95% CI 0.85-0.94), ranging from  0.82-0.98 in the included studies, vs. CXR 0.47 (95% CI 0.31- 0.63) ranging from 0.09 to 0.75
• Summary specificity: US 0.99 (95% CI 0.97-1.00, ranging from  0.96-1.00 vs. CXR 1.00 (95% CI 0.97- 1.00), ranging from 0.98 to 1.00

There possible weaknesses of this study, including blinding in the original studies, and several studies may or may not have been at risk for bias as their risk of bias was ‘unclear’.  However, the results were consistent across the studies analyzed and remained similar after sensitivity analysis.

Several anatomical as well as patient care issues may confound US findings for pneumothorax such as the presence of bleb, prior thoracic surgery or pathology, as well as main stem intubation.

Bottom line:  While the presence of pneumothorax is on either CXR or US is highly likely to represent the a true pneumothorax, ultrasound is a far superior screen for the detection of pneumothorax in the trauma patient.

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