Erik D. Barton

Prehospital needle aspiration and tube thoracostomy in trauma victims: A six-year experience with aeromedical crews

The use of prehospital tube thoracostomy (TT) for the treatment of suspected tension pneumothorax (TPtx) in trauma patients is controversial. A study is presented that reviews a 6-year experience with the use of needle catheter aspiration (NA) and chest tubes performed in the field by air medical personnel. Prehospital flight charts and hospital records from 207 trauma patients who underwent one or both of these procedures in the field were retrospectively reviewed. The clinical indications used to determine treatment are presented for both procedures. Improvement in clinical status of patients observed by flight personnel were similar for both treatment groups (54% for NA, 61% for TT). Thirty-two (38%) of the TT patients had failed NA attempts prior to chest tube placement. Average time on scene (T.O.S.) was significantly greater for the TT group (25.7 min versus 20.3 min for NA group). Fewer patients were pronounced dead on arrival (D.O.A.) with TT treatment compared to NA alone (7% versus 19%, respectively). Injury severity scores, number of hospital complications, length of stay (L.O.S.), and total hospital costs were not different between the two groups. There were no cases of lung damage or empyema formation associated with prehospital TT treatment. Overall mortality was similar for both groups. From these data, we conclude that NA is a relatively rapid intervention in the treatment of suspected TPtx in the prehospital setting; however, TT is an effective adjunct for definitive care without increasing morbidity or mortality. A better understanding of the physiology of intrapleural air masses is needed to determine the most effective decompression requirements prior to aeromedical transport.

Domestic violence in the emergency department: How do women prefer to disclose and discuss the issues?

The purpose of this study was to survey women presenting to the emergency department (ED) and determine from them how best to identify and discuss issues of domestic violence (DV). An anonymous 10-question survey was given to ambulatory females presenting to the ED. It was conducted at two affiliated university hospital EDs, one an urban trauma center (ED 1) and the other an ED in an affluent suburban setting (ED 2). Two hundred forty-three women responded (73% response), 153 (63%) from ED 1 and 90 (37%) from ED 2. There were 21 women (9%) currently being abused, and 109 (45%) were past victims. Of all victims, 40 (36%) would only divulge DV if asked directly, 28 (25%) would volunteer this information without being asked, and 12 (11%) would not report DV even if asked. Of women who would reveal DV only if asked directly, 52 (45%) felt very comfortable disclosing this to an ED physician, although only 27 (24%) would reveal DV at a triage encounter. Of past or current victims, 43 (39%) would not disclose DV if they knew that ED personnel were required to report it. In conclusion, the ED is an appropriate setting to discuss DV issues. A significant percentage of women will disclose DV only if asked directly about it. Many victims of DV feel very comfortable discussing DV with ED physicians and nurses, although they may be less likely to reveal DV incidents at a triage encounter. Mandatory reporting laws may be an impediment to identifying cases of abuse.

The pathophysiology of tension pneumothorax in ventilated swine.

It remains unclear as to whether the cardiovascular collapse observed in tension pneumothorax (TP) is strictly a mechanical pressure-related phenomenon or secondary to hypoxemia. This study describes the pathophysiologic changes associated with a surgically induced progressive TP in a ventilated swine model. With a balloon occlusion catheter surgically placed into the pleural space, progressive volumes of pneumothorax were created in six anesthetized pigs on positive-pressure ventilation. Air was introduced into the right hemithorax in 100-mL increments every 4-5 min, with measurements of heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), mean intrapleural pressure (MIP), oxygen saturation (O2%), arterial blood gas (ABG), and cardiac output (C.O.). With the induced progressive TP, results showed that O2% measures decreased immediately and continued to decline throughout the experiment to levels below 50% prior to cardiovascular collapse. The MAP and HR remained relatively stable until approximately 57% total lung capacity progressive TP (600 mL) was reached. At this point, a significant decline in MAP and increase in HR was noted, indicating tension physiology. The C.O. showed a small but significant decrease after 200 mL of air was injected, with a progressive decline after this point. At > 97% total lung capacity TP, lethal cardiovascular collapse occurred in all animals and was associated with an abrupt drop in C.O., HR, and MAP. There was a concurrent equalization of MIP with CVP at the point of collapse. Arterial blood gas measures correlated with O2% trends during the trials. We conclude that the findings of this study support the alternative hypothesis that significant hypoxemia occurs early and precedes hypotension in ventilated animals with TP. Occlusive mechanical compression, suggested by equalization of MIP and CVP, is probably a late event.

Stab wound to the chest with acute pericardial tamponade

A 21-year-old male presented to the trauma unit after he was stabbed once with a knife in the left anterior chest. The patient was awake and combative, very intoxicated, with a systolic blood pressure of 90 mmHg by palpation and a heart rate of 110 beats per min. Physical examination revealed distended neck veins, a single 1.5 cm stab wound to the left parasternal area at the third ICS (noted by clip on x-ray, Fig. 1), poorly auscultated heart sounds, and palpable femoral pulses that went away with inspiration. Chest radiograph (Fig. 1) showed a pear-shaped cardiac silhouette, though not markedly enlarged, and a significant left hemothorax. A diagnosis of acute pericardial tamponade was made, and the patient was taken immediately to the operating room for thoracotomy and successful repair of a stab wound of the right ventricle. Figure 2 (courtesy of Richard Wolfe, MD, Massachusetts General Hospital, Boston, MA) presents an example of an echocardiogram depicting a pericardial effusion. Pericardial fluid is imaged as a black (hypoechoic) crescent area separating the apex of the heart from the pericardium, seen as a white ring (arrow) at the inferior aspect of the scan. Tamponade is defined sonographically as the presence of both pericardial effusion (PE) and diastolic collapse of the right ventricle. Figure 3 (courtesy of Michael H. Picard, MD, of Harvard Medical School, Boston, MA) demonstrates the collapse of the right ventricular outflow track (RVOT) and its position relative to the left ventricle (LV), the left atrium (LA), and the aortic valve (AV).

Airbag safety: Deployment in an automobile crash with a fall from height

Airbag restraint systems have demonstrated a significant reduction in mortality in motor vehicle crashes (MVCs). While airbag devices are effective primarily in frontal or near-frontal impacts, little is known about the efficacy of these devices in nonfrontal types of collisions. Moreover, there are reports of injuries specific to airbag deployment that have led some investigators to question the benefit of such devices. This article reports a rollover MVC with a considerable fall from height in which lap/shoulder belts were used in addition to airbag deployment that resulted in protection of the driver from injury. The outcome of this case continues to support the combination of belt and airbag restraint systems as the most effective occupant protection in both frontal and nonfrontal types of MVCs.