Bigger is better: Comparison of alternative devices for tension hemopneumothorax and pulseless electrical activity in a Yorkshire swine model.

BACKGROUND: Tension pneumothorax is a cause of potentially preventable death in prehospital and battlefield settings and 14-gauge angiocatheter (14G AC) decompression remains the current treatment standard, despite its high incidence of failure. Traumatic pneumothorax is often associated with hemothorax, but 14G AC has no proven efficacy for associated hemothorax. We sought to compare the 14G AC to three alternative devices for treatment of tension hemopneumothorax (t-H/PTX) in a positive-pressure ventilation swine model. METHODS: Our tension model was modified to incorporate a persistent air leak and pleural blood. Tension physiology was achieved with escalating carbon dioxide insufflation via transdiaphragmatic trocar, and 10% estimated blood volume was instilled into each chest. Intervention was randomized between 14G AC, 10-gauge angiocatheter (10G AC), modified Veress-type needle (mVN), and 3-mm laparoscopic trocar (LT). After recovery, serial tension-induced pulseless electrical activity (PEA) events were induced and decompressed. Success of rescue, time to rescue, and physiologic data were recorded. RESULTS: One hundred ninety-five t-H/PTX and 88 PEA events were conducted in 25 swine. Laparoscopic trocar and 10G AC were more successful and had faster median time to rescue for t-H/PTX compared with 14G AC, whereas mVN performed comparably. Following PEA, 14G AC and mVN succeeded at rescue only 50% and 57% of the time, whereas 10G AC and LT had 100% success at return of spontaneous circulation. Time to successful return of circulation following PEA did not differ between devices; however, there was a noticeable difference in the rate of meaningful hemodynamic recovery following PEA favoring LT and 10G AC. There were no significant injuries noted. CONCLUSIONS: While mVN performed comparably to 14G AC, both have unacceptable failure rates. Ten-gauge AC and LT performed superiorly in both t-H/PTX and PEA. We believe there is now ample evidence supporting replacement of the 14G AC with 10G AC in current treatment recommendations.

Use of a low-concentration heparin solution to extend the life of central venous catheters in African green monkeys (Chlorocebus aethiops).

Normal hematologic values for African green monkeys have been reported, but these results are confounded by the effect of chemical restraint (for example, ketamine), physical restraint, and capture stress. The dual-lumen central venous catheter, jacket, and tether combination we describe here allows intravenous fluid administration and repeated blood sampling without the use of anesthesia or inducing capture-related stress. The use of a low-concentration heparin solution for catheter maintenance significantly increased the mean patency time, compared with a saline-only catheter flush solution. Adding a low-concentration heparin solution creates a suitable system for serial blood collection in the African green monkey for as long as 25 d.

Short-course postexposure antibiotic prophylaxis combined with vaccination protects against experimental inhalational anthrax.

Prevention of inhalational anthrax after Bacillus anthracis spore exposure requires a prolonged course of antibiotic prophylaxis. In response to the 2001 anthrax attack in the United States, approximately 10,000 people were offered 60 days of antibiotic prophylaxis to prevent inhalational anthrax, but adherence to this regimen was poor. We sought to determine whether a short course of antibiotic prophylaxis after exposure could protect non-human primates from a high-dose spore challenge if vaccination was combined with antibiotics. Two groups of 10 rhesus macaques were exposed to approximately 1,600 LD50 of spores by aerosol. Both groups were given ciprofloxacin by orogastric tube twice daily for 14 days, beginning 1-2 h after exposure. One group also received three doses of the licensed human anthrax vaccine (anthrax vaccine adsorbed) after exposure. In the ciprofloxacin-only group, four of nine monkeys (44%) survived the challenge. In contrast, all 10 monkeys that received 14 days of antibiotic plus anthrax vaccine adsorbed survived (P = 0.011). Thus postexposure vaccination enhanced the protection afforded by 14 days of antibiotic prophylaxis alone and completely protected animals against inhalational anthrax. These data provide evidence that postexposure vaccination can shorten the duration of antibiotic prophylaxis required to protect against inhalational anthrax and may impact public health management of a bioterrorism event.

Fungal diseases of rabbits.

Although fungal diseases in rabbits are reported, they are encountered infrequently in clinical practice. The most common fungal disease is a superficial dermatophytosis, with deep mycotic infections being rare. Rabbits can be asymptomatic carriers of dermatophytes and should be considered a potential source of zoonotic exposure. Treatment protocols often are based on common small animal regimes. Rabbits also have normal gastrointestinal yeast that often is found on routine fecal examinations.