UMEM Educational Pearls - Critical Care

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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