Conference Follow Up: September 4th 2013

Dr. Gatton's Trauma lecture:

1 - Hypothermia in trauma? We discussed how although we always learn that hypothermia is bad for trauma ... it is part of the deadly triad. However, there are some theories that it could improve outcomes, particularly in head trauma. See this cochrane review on hypothermia in head trauma. Although limited in study quality, and finding no statistically significant improved outcome, there was a trend toward mortality benefit. Take a look at it yourself.

"The review authors found that fewer people died or became severely disabled if they were treated with hypothermia, but this finding may be due to chance. It was also found that patients given hypothermia were more likely to develop pneumonia, and some patients died from pneumonia, but the increased risk of pneumonia could also be due to chance. "

2- Hyperventilation in ICH. We discussed the role of hyperventilation to decrease ICP and improv CPP in intracranial hemorrhage/trauma. Below are some resources on this debated topic.

Here is a great review article in CHEST. 

AHA Intracranial Hemorrhage GUIDELINES:

"Hyperventilation
Hyperventilation is one of the most effective methods available for the rapid reduction of ICP. The CO₂ reactivity of intracerebral vessels is one of the normal mechanisms involved in the regulation of CBF. Experimental studies using a pial window technique have clearly demonstrated that the action of CO₂ on cerebral vessels is exerted via changes in extracellular fluid pH.⁷⁴ Molecular CO₂ and bicarbonate ions do not have independent vasoactivity on these vessels. As a result, hyperventilation consistently lowers ICP. Despite the effectiveness of hyperventilation in lowering ICP, broad and aggressive use of this treatment modality to substantially lower PCO₂ levels has fallen out of favor, primarily because of the simultaneous effect on lowering CBF. Another characteristic of hyperventilation that limits its usefulness as a treatment modality for intracranial hypertension is the transient nature of its effect. Because the extracellular space of the brain rapidly accommodates to the pH change induced by hyperventilation, the effects on CBF and on ICP are short-lived. In fact, after a patient has been hyperventilated for >6 hours, rapid normalization of arterial PCO₂ can cause a significant rebound increase in ICP. The target levels of CO₂ for hyperventilation are 30 to 35 mm Hg. Lower levels of CO₂ are not recommended.^75"

Bites:

1- Study on primary vs secondary closure of dog bite wounds: Great discussion of dog bites. Study showed significant cosmetic improvement with early closure with no statistically significant change in infection rate.

2- Link on how and when to report animal bites to the NYC.gov health department.

Oncologic Emergencies

1- Attached are two awesome Evidence Based Medicine articles from 2010 on Oncologic Emergencies. 

2- We discussed the early ultrasonographic signs of pericardial tamponade. We can all easily see effusions, but which ones are resulting in tamponade physiology require some advanced echo techniques that we can all learn. This will make us rock stars when presenting the patient with greater urgency to our Cardiothoracic colleagues. See the below links for studies and tips.

 Probably the best ARTICLE on US Findings in Tamponade

Here is a fantastic review from Stanford's ICU with great diagrams, images and figures to explain the physiology. 

NEJM Review Article on Tamponade: 

n the absence of my- ocardial disease or injury, echocardiography dem- onstrates the usually circumferential fluid layer and compressed chambers with high ventricular ejection fractions.24 Doppler study discloses marked respiratory variations in transvalvular flows. One mechanism of pulsus paradoxus is visible: on inspi- ration, both the ventricular and atrial septa move sharply leftward, reversing on expiration1; in other words, each side of the heart fills at the expense of the other, owing to the fixed intrapericardial volume. The inferior vena cava is dilated, with little or no change on respiration.Among echocardiographic signs, the most char- acteristic, although they are not entirely specific, are chamber collapses, which are nearly always of the right atrium and ventricle. During early diastole, the right ventricular free wall invaginates, and at end di- astole, the right atrial wall invaginates.25 Right ven- tricular collapse is a less sensitive but more specific finding for tamponade, whereas right atrial col- lapse is more specific if inward movement lasts for at least 30 percent of the cardiac cycle. Right atrial collapse may be seen in patients with hypo- volemia who do not have tamponade. In about 25 percent of patients, the left atrium also collapses, and this finding is highly specific for tamponade. Left ventricular collapse usually occurs under spe- cial conditions such as localized postsurgical tam- ponade. These wall changes occur when respective chamber pressures temporarily fall below the peri- cardial pressure.24,25