Randomised controlled trial comparing marksmanship following application of a tourniquet or haemostatic clamp in healthy volunteers.

BACKGROUND: In a care under fire situation, a first line response to haemorrhage is to apply a tourniquet and return fire. However, there is little understanding of how tourniquets and other haemorrhage control devices impact marksmanship. METHODS: We compared the impact of the iTClamp and the Combat Application Tourniquet (CAT) on marksmanship. Following randomisation (iTClamp or CAT), trained marksmen fired an AR15 at a scaled silhouette target in prone unsupported position (shooting task). Subjects then attempted to complete the shooting task at 5, 10, 15, 30 and 60 min post-haemorrhage control device application. RESULTS: All of the clamp groups (n=7) completed the 60 min shooting task. Five CAT groups (n=6) completed the 5 min shooting task and one completed the 5 and 10 min shooting task before withdrawing. Four CAT groups were stopped due to unsafe handling; two stopped due to pain. When examining hits on mass (HOM) for the entire shooting task, there was no significant difference between tourniquet and iTClamp HOM at 5 min (p=0.18). However, there was a significant difference at 10 min, p=0.003 with tourniquet having significantly fewer HOM (1.7±2.7 HOM) than the iTClamp (8.1±3.3 HOM) group. The total effective HOM for the entire 60 min shooting task showed that the iTClamp group achieved significantly (p=0.001) more HOM than the tourniquet group. Over the entire 60 min shooting exercise, the iTClamp group achieved a median 72% (52/72) of available HOM while the tourniquet group obtained 19% (14/72). CONCLUSIONS: Application of a tourniquet to the dominant arm negates effective return of fire in a care under fire setting after a brief time window. Haemorrhage control devices that preserve function may have a role in care under fire situations, as preserving effectiveness in returning fire has obvious operational merits.

Asymmetric recovery in cerebellar-deficient mice following unilateral labyrinthectomy.

The term "vestibular compensation" refers to the resolution of motor deficits resulting from a peripheral vestibular lesion. We investigated the role of the cerebellum in the compensation process by characterizing the vestibuloocular reflex (VOR) evoked by head rotations at frequencies and velocities similar to those in natural behaviors in wild-type (WT) versus cerebellar-deficient Lurcher (Lc/+) mice. We found that during exploratory activity, normal mice produce head rotations largely consisting of frequencies < or =4 Hz and velocities and accelerations as large as 400 degrees/s and 5,000 degrees/s2, respectively. Accordingly, the VOR was characterized using sinusoidal rotations (0.2-4 Hz) as well as transient impulses (approximately 400 degrees/s; approximately 2,000 degrees/s2). Before lesions, WT and Lc/+ mice produced similar VOR responses to sinusoidal rotation. Lc/+ mice, however, had significantly reduced gains for transient stimuli. After unilateral labyrinthectomy, VOR recovery followed a similar course for WT and Lc/+ groups during the first week: gain was reduced by 80% for ipsilesionally directed head rotations on day 1 and improved for both strains to values of approximately 0.4 by day 5. Moreover, responses evoked by contralesionally directed rotations returned to prelesion in both strains within this period. However, unlike WT, which showed improving responses to ipsilesionally directed rotations, recovery plateaued after first week for Lc/+ mice. Our results show that despite nearly normal recovery in the acute phase, long-term compensation is compromised in Lc/+. We conclude that cerebellar pathways are critical for long-term restoration of VOR during head rotation toward the lesioned side, while noncerebellar pathways are sufficient to restore proper gaze stabilization during contralesionally directed movements.

Ozone uptake in healthy adult males during quiet breathing.

Experimental measurements of ozone (O3) uptake are needed for validation of dosimetry model parameters and in predictions as well as for determining factors affecting uptake and for making comparisons between subpopulations or across species. In this study, 10 healthy adult male subjects were exposed to 0.3 ppm O3 while seated and breathing naturally through the nose or mouth. Total respiratory tract O3 uptake, spontaneous breathing parameters, and respiratory gas exchange were measured for 10 min under steady-state conditions. The exposure protocol was replicated in each subject approximately 2 weeks after the first visit. On each visit, health exams were performed and spirometric lung measurements were obtained. The experimental design provided comparisons of total O3 uptake during nasal and oral breathing, differences in uptake in an individual at two time points, and an examination of between-subject variability in O3 uptake. Exposure to O3 had no effect on the breathing parameters or gas exchange. Oral and nasal breathing frequency averaged 16.2 +/- 1.1 (SE) and 16.0 +/- 1.2 breaths per minute with tidal volumes averaging 651 +/- 46 and 669 +/- 67 ml, respectively. A significant correlation (p < 0.01) was found for the minute volume during resting breathing with the percentage of uptake. The percentage of O3 uptake was consistently higher (p = 0.02) during oral breathing (76.5% +/- 3.3) than during nasal breathing (73.1% +/- 3.0) although this difference may not be biologically significant. The variability in percentage of uptake between subjects was substantial with calculated uptakes ranging from 51 to 96%, a difference of about 45%. Variability in percentage of uptake for an individual was less with the maximal difference between the first and second visits being about 20%; the average difference, however, was only about 3%. We conclude that total percentage of O3 uptake is approximately 75% in adult males during resting breathing. It is slightly greater during oral than during nasal breathing, will vary considerably among subjects, and is moderately reproducible within a subject.

Air medical transport: what the family wants to know.

INTRODUCTION: The needs of family members of intensive care unit patients are well-documented, but there is little published about the specific needs of family members of air medical patients. PURPOSE: This study was devised to identify family member's information needs regarding air medical transport. METHODS: Using a descriptive correlational design, 100 family members of air medical patients completed a 14-item Likert-format questionnaire. Each item addressed an information need and asked how important the information was to the family member and how much of this information they received. RESULTS: The information needs most frequently ranked as very important related to the patient's condition, the patient's admitting unit at the receiving hospital, and being able to see the patient prior to flight. Information most frequently received by the family related to the patient's condition. CONCLUSION: Flight crews need to be cognizant of families' needs and develop ways to improve communication with the family to meet those needs.

Fractal and morphometric analysis of lung structures after canine adenovirus-induced bronchiolitis in beagle puppies.

Acute viral respiratory infections are commonly associated with alteration in lung growth and with chronic obstructive disease. However, it is difficult to quantify these changes in lung function. We determined that the recently described techniques of fractal analysis gave additional information about the changes in lung function after viral illness compared to standard morphometric techniques. Fractal and morphometric parameters change with lung growth after acute infection with canine adenovirus type 2 (CAV2, n = 5) or no infection (controls, n = 6) in beagle puppies. Lung pathological studies showed areas of obliterative bronchiolitis and chronic small airways inflammation but no emphysema in the CAV2-infected puppies. Morphometric studies at approximately 236 days of age demonstrated accelerated lung growth in the CAV2-infected dogs as evidenced by significant increases in lung volume (VL) and internal surface area (ISA). Fractal analysis showed an increased fractal dimension (Df) of the alveolar perimeter length in the CAV2 group associated with increased growth that was similar to the percentage change in VL and ISA. These data suggest that a single infection with CAV2 in beagle puppies accelerates lung growth and increases the complexity (Df) of the alveolar structure.