Fraction of Inspired Oxygen Delivered by Elisée™ 350 Turbine Transport Ventilator With a Portable Oxygen Concentrator in an Austere Environment.

BACKGROUND: Management of critically ill patients in austere environments is a logistic challenge. Availability of oxygen cylinders for the mechanically ventilated patient may be difficult in such a context. One solution is to use a ventilator able to function with an oxygen concentrator (OC). METHODS: We tested two Elisée™ 350 ventilators paired with SeQual Integra 10-OM oxygen concentrators (OC) (Chart Industries, http://www .chartindustries.com) and evaluated the delivered fraction of inspired oxygen (Fio2). Ventilators were connected to a test lung and Fio2 was measured and indicated by the ventilator. Continuous oxygen was generated by the OC from 0.5L/min to 10L/min, and administered by the specific inlet port of the ventilator. Several combinations of ventilator settings were evaluated to determine the factors affecting the delivered Fio2. RESULTS: The Elisée 350 turbine ventilator is able to deliver a high Fio2 when functioning with an OC. However, modifications of the ventilator settings such as an increase in minute ventilation, inspiratory-to-expiratory ratio, and positive end-expiratory pressure affect delivered Fio2 despite steady-state oxygen flow from the concentrator. CONCLUSION: OCs provide an alternative to oxygen cylinders for delivering high Fio2 with a turbine ventilator. Nevertheless, Fio2 must be monitored continuously, since it decreases when minute ventilation is increased.

Experience Of A US Air Force Surgical And Critical Care Team Deployed In Support Of Special Operations Command Africa.

An eight-person team of conventional US Air Force (USAF) medical providers deployed to support US Special Operations Forces (SOF) in North and West Africa for the first time in November 2014. The predeployment training, operations while deployed, and lessons learned from the challenges of performing surgery and medical evacuations in the remote desert environment of Chad and Niger on the continent of Africa are described. The vast area of operations and far-forward posture of these teams requires cooperation between partner African nations, the French military, and SOF to make these medical teams effective providers of surgical and critical care in Africa. The continuous deployment of conventional USAF medical providers since 2014 in support of US Special Operations Command Africa is challenging and will benefit from more medical teams and effective air assets to provide casualty evacuation across the vast area of operations.

Comparative testing of new hemostatic agents in a swine model of extremity arterial and venous hemorrhage.

OBJECTIVE: To compare advanced hemostatic dressings: HemCon (HC), QuikClot ACS+ (advanced clotting sponge, and two granular agents: Celox (CX) and WoundStat (WS), with a standard field dressing in a swine model of extremity hemorrhage. METHODS: We randomized 30 animals to treatment with a standard dressing or a hemostatic agent applied to a 2 x 6-mm injury in the femoral artery and vein after 45 s of free bleeding. Animals received 500 mL Hextend 15 min after the bleeding commenced without further resuscitation. End point was survival to 120 min or non-survivable blood pressure. RESULTS: Survival to 120 min among treatment groups was 100% (WS), 83% (CX), 67% (HC), and 50% (ACS+). No control animals survived. Postinjury blood loss (mL/kg) was 4.6 (WS), 12.9 (CX), 10.0 (HC), and 15.8 (ACS+) compared to 27.0 for controls. CONCLUSION: All hemostatic dressings result in significantly less blood loss and improved survival over standard gauze dressing.

Magnamosis: magnetic compression anastomosis with comparison to suture and staple techniques.

PURPOSE: An ideal anastomosis between hollow viscera should be easily performed, strong, and operator independent. We hypothesized that transluminal attraction between magnets in the intestine could be harnessed to create an intestinal compression anastomosis (magnamosis) with these characteristics. We further hypothesized that variation of attraction force and geometry of compression would affect the quality of the intestinal anastomosis. METHODS: We designed a self-orienting device composed of 2 neodymium-iron-boron magnets affixed to polytetrafluoroethylene moldings. Two topologies were evaluated: one designed with 'uniform' compression and the other with 'gradient' compression. Sixteen young adult pigs (Sus scrofa) underwent laparotomy with creation of a magnetic side-to-side anastomosis: 8 with the uniform device and 8 with the gradient device. Each also had a stapled anastomosis, and 5 had an additional hand-sutured anastomosis. Animals were euthanized at 1, 2, and 3 weeks after operation, then anastomoses were compared on the basis of gross appearance, histology, functional radiography, and mechanical integrity. RESULTS: All magnetic devices formed patent anastomoses without leak. One stapled anastomosis resulted in a contained leak. Mechanical integrity of magnetic anastomoses was not statistically significantly different from staple or suture counterparts, and there was a trend toward greater strength with magnetic anastomoses. Comparison between device types revealed the gradient device trended toward greater strength and earlier patency (67% vs 33% at 1 week). There was no evidence of stenosis, and histologic examination demonstrated tissue remodeling with mucosal and serosal apposition across the magnamoses. CONCLUSIONS: The magnetic compression anastomosis (magnamosis) device is a safe and effective means of sutureless full-thickness intestinal anastomosis with serosal apposition in a pig model. Gradient compression is superior to uniform compression. This technique is compatible with endoscopic and natural orifice approaches.

Dextran polymer hemostatic dressing improves survival in liver injury model.

BACKGROUND: Improvements in early hemorrhage control could result in more favorable outcomes. Several advanced hemostatic dressings are available; however, none meets the ideal characteristics defined by the United States Army. We studied the effects of a new dextran polymer hemostatic dressing on survival, blood loss, and blood pressure in a swine model of severe liver injury. METHODS: We randomized 12 Yorkshire swine to treatment with either standard laparotomy pads or laparotomy pads coated with a dextran polymer (Bloxx). These dressings are visually identical, and investigators were not informed of the dressing assignment. We transected the left medial lobe of the liver in the anesthetized swine with a large knife, applied dressings immediately, and held pressure for 7 min. The animals received a weight-based maintenance crystalloid infusion without further resuscitation. Endpoints were blood loss, blood pressure, early mortality (120 min), and tissue histology. RESULTS: Baseline and pre-injury characteristics were similar between all animals. Three of six animals in the control group survived for 2 h while all six animals treated with Bloxx survived (P=0.05). Similarly, animals in the Bloxx group experienced less blood loss (10.4+/-8.8 mL/kg versus 28.3+/-13.0 mL/kg, P=0.025) and higher post-injury blood pressure than the control group. Bloxx was not associated with macroscopic or microscopic tissue damage. CONCLUSIONS: Bloxx is superior to standard laparotomy sponges in this model of lethal liver injury. Further study of this dressing is warranted to determine its potential for use in civilian and military trauma.

Nonoperative management of bronchial injury in a 21-month-old child.

Bronchial laceration is an uncommon complication of blunt trauma in children. Treatment of bronchial laceration has involved thoracotomy with primary repair of the bronchial injury or nonoperative management with tube thoracostomy. We report a 21-month-old boy who sustained a large tear of the right upper lobe bronchus after an automobile/pedestrian accident in whom nonoperative management resulted in a favorable outcome. The relevant literature is reviewed, and an algorithm for management is proposed.