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At least 325 records · Page 18Linked to original sources
PubMed1981

Use of military antishock trouser in a child.

Angiographic localization and embolization has emerged as the preferred mode of therapy for arterial bleeding associated with pelvic fractures but is not always definitive. Our experience demonstrates the use of an external counter pressure device (MAST) as an essential part of the pediatric surgeon's armamentarium and suggests the need for concurrent venography during angiographic localization of pelvic bleeding sites.

Child↗
PubMed1991

Intraosseous infusion of fluids in the initial management of hypovolemic shock in young subjects.

Immediate aggressive fluid resuscitation of a child with life-threatening hemorrhagic shock provides the difference between life and death. Obtaining venous access in the hypovolemic child sometimes is difficult and time consuming. In order to evaluate the benefit of prehospital administration of intraosseous fluids into the tibial bone marrow as a method of gaining quick access to the systemic circulation and in resuscitating victims from severe hypovolemic shock, 13 puppies weighing 4.6 to 10 kg were subjected to progressive, controlled exsanguination until their mean arterial pressure (MAP) was 20% or less of their baseline MAP for 5 minutes (maxishock). Then an 18-gauge intraosseous needle was inserted into the tibial bone marrow and lactated Ringer's solution was infused at 300 mm Hg of pressure until a volume three times the blood loss had been administered. The MAP, central venous pressure, arterial blood gases, hematocrit, serum lactate, and urine output were recorded at 10, 20, 30, 45, 60, 90, and 120 minutes after the onset of maxishock. At the end of the experiment the left lung of each animal was sent to the pathology department to investigate the possibility of bone marrow emboli. The results were compared with a group of control dogs with maxishock and no treatment, and a group of dogs with maxishock treated with a canine military antishock trousers inflated to 50 to 55 mm Hg and no fluids. The average needle insertion time was 16 seconds; the rate of infusion of fluids varied from a maximum of 25.7 mL/min to a minimum of 4.5 mL/min, with a mean of 10.6 mL/min.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Thromboembolic complications following radical retropubic prostatectomy. Influence of external sequential pneumatic compression devices.

The influence of external sequential compression devices (SCD) on the development of postoperative thromboembolic events was studied in 1,300 consecutive men undergoing radical retropubic prostatectomy. Of the 784 men whose perioperative management did not involve the SCD, in 9 (1.1%) thromboembolic complications developed: 7 (0.9%) pulmonary emboli (PE), and 2 (0.3%) deep venous thrombosis (DVT). In the 516 patients with SCD prophylaxis there were 12 (2.3%) thromboembolic complications: 9 (1.7%) PE, and 3 (0.6%) DVT. In patients with SCD prophylaxis, the delay from the time of surgery to the onset of thromboembolic symptoms averaged 20 +/- 12 days, and all but 1 patient suffered the complication while an outpatient; this was significantly longer than in men without SCD (11 +/- 5 days; p < 0.05). This delay in thromboembolic events was the only benefit we could demonstrate with SCD. Recognizing that most thromboembolic complications occur after discharge, new strategies for prophylaxis may be needed during this period, and patients should be well informed about the signs and symptoms of PE and DVT to avoid a delay in diagnosis and treatment.

Gravity Suits↗
PubMedDate not supplied

An objective determination of +Gz acceleration tolerance.

Until recently, human +Gz acceleration tolerance has relied solely on subjective criteria relating to loss of vision. By use of newly developed noninvasive instrumentation using a transcutaneous Doppler flow system, objective end point criteria have been developed based on measured blood flow to the head. The system consists of miniature 8 MHz Doppler sensors (2 x 1 x 0.5 cm) placed on the forehead over both frontal branches of the temporal arteries to detect blood flow velocity from back scattered ultrasound. Its use has allowed for correlation of altered, decreased and actual reversal of eye level blood flow with subsequent central light loss. Over 100 subjects have now been studied during more than 2,000 centrifuge runs. Objective changes in temporal artery flow velocity consistently preceded visual degradation for each subject during all acceleration profiles. No subject has gone unconscious without first exhibiting a minimum 6 sec of total flow cessation. Retrograde flow followed by complete flow cessation always preceded central light loss. Results indicate that this method can be successfully used with a wide variety of tasks during exposure to +Gz acceleration. It is recommended for use during evaluation of protective maneuvers or devices on the centrifuge or during actual flight in high performance aircraft. It may also serve as a potential safety monitor during space Shuttle re-entry if there is doubt about a passenger's cardiovascular status.

Acceleration↗
PubMed1988

The prevention of adverse physiological change in Space Station crewmembers.

Various physiological countermeasures, consisting primarily of isotonic and isometric exercises but also including prescribed nutrient intake, have been used in all manned spaceflights exceeding about one month in duration. So consistent has been this practice that the effects of weightlessness on the human, unconfounded by the use of countermeasures, are difficult to discern. Equally elusive, in the absence of control studies conducted in weightlessness, is an accurate assessment of the efficacy of the countermeasures themselves. Changes in body composition occurring during and following flights from Gemini through Shuttle, when compared with changes during and following bedrest, demonstrate certain mitigating effects that may be attributable to countermeasures and which provide some rationale for the choice of countermeasures in the Space Station.

Adaptation, Physiological↗
PubMed1988

Radiation dose and shielding for the Space Station.

Significant differences in dose prediction for Space Station arise depending on whether or not the magnetic field model is extrapolated into the future. The basis for these calculations is examined in detail, and the importance of the residual atmospheric layer at altitudes below 1000 km, with respect to radiation attenuation is emphasized. Dosimetry results from Shuttle flights are presented and compared with the computed results. It is recommended that, at this stage, no extrapolation of the magnetic field into the future be included in the calculations. A model adjustment, to replace this arbitrary procedure is presented. Dose predictions indicate that, at altitudes below 500 km and at low inclination, and with nominal module wall thickness (0.125 in. aluminum), orbit stay times of 90 days in Space Station would result in quarterly radiation doses to the crew, which are well within present limits both for males and females. Countermeasures would be required for stay times of a year or more and the measure of increasing shielding is examined.

Aluminum↗
PubMed1992

Radiation situation determining the possibility of a manned flight to Mars and back.

Possible manned flights toward Mars are discussed from the viewpoint of radiation hazard. A standard situation is considered for the fast two times crossing of the Earth radiation belts. The flight to Mars is shown to be practically impossible without a special system of radiation shelters, because of the effect of penetrating galactic and solar radiations which are responsible for almost maximum permissible doses. But even in case there were radiation shelters on board the spacecraft their flights are undesirable in the periods of maximum and minimum solar activity. It would obviously be worthwhile to schedule Martian flights for intervals in between minima and maxima of 11-year cycles of solar activity when primary cosmic rays levels are considerable reduced and flare activity is not yet sufficiently high. It should be mentioned that it would not be easy to select such allowed intervals. Further studies of that aspect are discussed.

Astronauts↗
PubMed1989

Transcutaneous oxygen tension measurements during hemorrhagic hypoperfusion using Trendelenburg and the pneumatic antishock garment.

Transcutaneous oxygen tension (PtCO2) was observed during hemorrhagic hypoperfusion using four therapeutic modalities: pneumatic antishock garment (PASG), 20 degrees Trendelenburg positioning, combined PASG-Trendelenburg, and whole blood infusion. Anesthetized mongrel dogs were mechanically ventilated. A heated transcutaneous oxygen sensor was applied to the skin overlying the sternum. Animals were bled over 10 min of 25% of their calculated blood volume. A therapeutic intervention was applied at the onset of hemorrhage (PASG, Trendelenburg, PASG-Trendelenburg or control). All animals were observed for 20 min, then during a 10-min shed blood reinfusion period, and for 20 min thereafter. PtCO2 was measured continuously and the following were measured serially: cardiac output, mean arterial pressure (MAP), mixed venous oxygen tension (MvO2), and arterial oxygen tension (PaO2). Cardiac index (CI) and the oxygen extraction ratio were calculated. PtCO2 decreased immediately after hemorrhage in all animals. Control values remained consistently below values for active interventions during this time. All groups regained baseline levels of PtCO2 after reinfusion of shed blood volume. PaO2 remained nearly constant during all experiments. MAP and CI fell in all groups following hemorrhage but did so less precipitously in the PASG group. The PASG and PASG-Trendelenburg groups showed the greatest increase in CI during reinfusion. These results suggest that when PtCO2 is relied upon as an indicator of adequacy of resuscitation during moderate hemorrhagic shock, that cutaneous perfusion may be improved by the PASG or Trendelenburg position, and that perfusion is most effectively restored by blood infusion.

Animals↗
PubMed1992

Influence of pressure supports on joint range of motion.

Burn patients often complain of restricted mobility following application of elasticized nylon anti-burn-scar supports. This study was designed to analyse the influence of this type of pressure garment on joint range of motion (ROM). Data were compiled from 80 burn-affected joints of 17 burn patients placed in a support for the first time. Joint ROM was measured directly prior to, and again immediately following, the donning of the pressure support. ROM was measured using standard goniometric techniques. Range of motion increased in 26 joints (32.5 per cent), decreased in 26 joints (32.5 per cent) and showed no change in 28 joints (35 per cent) after application of the pressure garment. There were no correlations between ROM results and age, time postburn and per cent TBSA in this population. Patients were also asked if movement felt any different after the support was applied. Their varied comments, such as movement felt easier or more difficult, were consistent with the actual ROM data. It appears that there is no predictably detrimental change in joint ROM due to the application of pressure garments.

Adult↗
PubMed1983

Venous return in hemorrhagic shock after application of military anti-shock trousers.

UNLABELLED: The effect of Military Anti-Shock Trousers (MAST) on inferior vena cava blood flow was studied during graded hypovolemia using a pump reservoir system and an in-line electromagnetic flowprobe. During hemorrhagic shock MAST inflation increased cardiac output 25.4% ( CONTROL: 0.92 +/- 0.09 l/min) and arterial pressure 50% ( CONTROL: 60 +/- 2 mmHg). The so-called "autotransfusion" effect due to blood displacement from the lower part of the body into the central circulation was found to be only 4.3 +/- 0.6 ml/kg, a volume much less than previously estimated in the literature. We conclude that MAST inflation reliably improves cardiac output and systemic blood pressure above the diaphragm in dogs subjected to hemorrhagic shock. This effect is mainly due to a diversion of the cardiac output to the upper half of the body due to impedance of flow to the abdomen and lower extremities, rather than to a significant volume shift constituting an autotransfusion of blood from the lower part of the body.

Animals↗