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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The potential for hypothermia to prevent or ameliorate ischemic injury to the central nervous system is well known. To determine if a more prolonged period of metabolic suppression with blood substitution is possible, a method was developed to lower body temperature to near the freezing point. Eight adult mongrel dogs underwent closed-chest extracorporeal circulation with both external and internal body cooling. As they were cooled, progressive hemodilution was employed until complete exsanguination and blood substitution with an aqueous solution was accomplished. Continuous circulation and a core temperature at a mean of 1.7 degrees C were maintained from 2 1/2 to 3 hours. After rewarming to 20 degrees C, the animals were autotransfused and allowed to recover. Of the eight animals, two died due to technical factors related to cardiac defibrillation. Of the six surviving animals, five survived over a long period and one died on the 10th postoperative day with hepatorenal failure resulting from a presumed blood transfusion incompatability reaction. All six showed normal neurological function and kennel behavior, except one dog with mild weakness of a hindlimb. When the dogs were sacrificed 1 to 2 months postoperatively, all organs were histologically normal. Specifically, there was no gross or microscopic evidence of ischemic or hypoxic injury to any central nervous system structures. This pilot study demonstrates that it is possible to successfully achieve complete exsanguination, blood substitution, and ultraprofound body temperature, while continuous circulation of the blood substitute is maintained. With the capability of controlling and repeatedly performing washout of the extracellular environment and by reaching lower temperatures, it may be possible to attain greater cellular metabolic suppression. This perhaps will extend the allowable times for circulatory arrest procedures. In addition, "bloodless ischemia" may be beneficial in removing both blood substances and formed elements which may mediate organ ischemia. With replacement of blood at warm temperatures, coagulopathy is avoided. This preliminary evidence demonstrates potential in the combination of ultraprofound hypothermia and complete blood component substitution. However, further study is required to confirm the potential of achieving circulatory arrest of longer duration.
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PMID:Ultraprofound hypothermia with complete blood substitution in a canine model. 201 79

Four newborns with adenovirus infection are described, and the profile of neonatal adenovirus disease is outlined based on the cases of these newborns and nine previously described. Characteristic historical features included prolonged rupture of membranes, maternal illness, vaginal delivery, and onset of illness within the first 10 days of life. Clinical findings included lethargy, fever or hypothermia, anorexia, apnea, hepatomegaly, bleeding, and progressive pneumonia. Thrombocytopenia, coagulopathy, and hepatitis were typical laboratory manifestations. Illness was severe and generally unremitting; only two survivors have been reported. Pathologic changes were prominent in lung, liver, and brain. Virus isolates, predominantly serotypes 3, 7, 21, and 30 were obtained from multiple sites and organs. Epidemiologic evidence suggests that viral acquisition from the mother, perhaps via the birth canal, is a major mode of transmission. Neonatal adenovirus infection, which is frequently disseminated and generally fatal, should be considered in the differential diagnosis of neonatal sepsis and pneumonia.
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PMID:Neonatal adenovirus infection: four patients and review of the literature. 203 95

Planned relaparotomy (temporary abdominal closure) was studied prospectively in 20 trauma patients. Four died in the first 24 hours from hypothermia, coagulopathy, shock (three), and septic shock (one). The 16 survivors had a Velcro-like prosthetic placed to facilitate abdominal closure and re-entry. Prosthetic was necessary in eight because bowel edema precluded fascial closure, and useful for removal of packing (three) and for the management of peritonitis (five). The prosthetic did not open spontaneously, nor was it associated with evisceration or bowel fistula. Temporary abdominal closure (TAC) permitted reappraisal and staged repair of intra-abdominal pathology, including bowel resection and anastomosis. TAC identified 14 problems early: bleeding (five), bile leaks (two), GI complications (six), liver necrosis (one). Five patients developed superficial wound infections, and three went on to develop fascial necrosis.
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PMID:Temporary abdominal closure (TAC) for planned relaparotomy (etappenlavage) in trauma. 219 Nov 42

Massive transfusion, or the rapid administration of a quantity of blood products that approximates an individual's blood volume, is associated with many potentially lethal complications. If the need for transfusion is immediate, ie, before adequate typing and crossmatching procedures can be completed, O negative RBCs can be given safely in the interim. Hypothermia caused by cold banked blood is aggravated by multiple environmental factors and should be aggressively avoided through the use of heat lamps, warming coils, blankets, and other warming devices. The coagulopathy seen in massive transfusion probably has a mixed etiology involving dilution and consumption of clotting factors and platelets. Although fresh frozen plasma and platelets both play a critical role in blood replacement, deficiencies should be treated with appropriate component therapy dictated by coagulation studies rather than by protocol. Transfusion reactions, the most serious type of which is the hemolytic reaction, may go unrecognized in the bleeding patient in critical condition. Hemolytic reactions can usually be prevented by careful attention to administrative and clerical accuracy. Although the overwhelming majority of the 10 million units of blood transfused annually are uncontaminated, transmission of hepatitis and the human immunodeficiency virus through blood products remains a significant screening problem. Posttransfusion hyperkalemia and acidosis are more likely to be related to inadequate resuscitation from shock than to administration of blood. Citrate toxicity and hypocalcemia are usually self-limiting disturbances. Prophylactic use of calcium chloride is dangerous and unnecessary. The complexity of the conditions necessitating massive transfusion demands frequent reevaluation of multiple laboratory and clinical factors for effective resuscitation and for safe administration of blood.
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PMID:Massive transfusion: complications and their management. 220 22

Packing the abdomen can be lifesaving when severe hepatic trauma is complicated by refractory hypothermia, coagulopathy, and continuing hemorrhage requiring large-volume transfusion. This report describes the successful use of abdominal packs and a modified silo in a child following blunt liver injury.
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PMID:Pediatric blunt liver injury and coagulopathy managed with packs and a silo: case report. 223 11

Massive transfusion may cause abnormalities of electrolytes, clotting factors, pH, and temperature and may occur in a scenario of refractory coagulopathy and irreversible shock. Identification of correctable variables to improve survival is complicated by the interplay of this pathophysiology. Temperature may be an under-appreciated problem in the genesis of coagulopathy. In vitro studies have demonstrated that platelet function and vascular response are critically temperature-dependent. We reviewed the records of 45 trauma patients without head injury or co-morbid medical illness who required massive transfusions. The mean Injury Severity Score was 55 +/- 6, a mean of 22.5 +/- 5 units of blood was transfused, and mortality was 33%. Nonsurvivors were more likely to have had penetrating injury (88% versus 55%), received more transfusions (26.5 +/- 9 versus 18.6 +/- 1, p less than 0.05), had lower pH (pH 7.04 +/- 0.06 versus 7.18 +/- 0.02, p less than 0.05), had lower core temperature (31 +/- 1 degree C versus 34 +/- 1 degree C, p less than 0.01), and had a higher incidence of clinical coagulopathy (73% versus 23%). Severe hypothermia (temperature less than 34 degrees C) occurred in 80% of the nonsurvivors and in 36% of survivors. Patients who were hypothermic and acidotic developed clinically significant bleeding despite adequate blood, plasma, and platelet replacement. Avoidance or correction of hypothermia may be critical in preventing or correcting coagulopathy in the patient receiving massive transfusion.
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PMID:Hypothermia and acidosis worsen coagulopathy in the patient requiring massive transfusion. 224 Mar 86

Previous studies of hypothermia and blood coagulation have focused on alterations in the levels of blood clotting elements using coagulation tests performed under normothermic conditions. However, because of the enzymatic nature of activated clotting factors, hypothermia should also be expected to affect clotting factor activities. Multiple determinations of activated partial thromboplastin times (APTT), prothrombin times (PT), and thrombin times (TT) were performed on commercially available normal human plasma at assay temperatures similar to those encountered clinically (25-37 degrees C). Both the APTT and the PT were significantly prolonged at temperatures below 35 degrees C (P less than 0.05). Clotting time correlated significantly with assay temperature in a negative exponential fashion for all three tests (r = -0.97 for APTT, -0.93 for PT, -0.71 for TT, P less than 0.001 for all regressions). Clotting time prolongation appears proportional to the number of enzymatic steps involved. These data indicate that the coagulopathy observed during hypothermia is, in part, independent of clotting factor levels.
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PMID:Hypothermia and blood coagulation: dissociation between enzyme activity and clotting factor levels. 225 17

Massive nonmechanical bleeding following severe liver injury is a difficult problem. Placement of intra-abdominal packs tamponades this nonmechanical bleeding and allows time for correction of various metabolic disturbances (ie, hypothermia, hypotension, acidosis, and coagulopathy). The purpose of this retrospective study was to evaluate the severity of these metabolic disturbances at the time of pack placement and the sequential improvement. It was found that most life-threatening disturbances that developed during the initial operative procedure could be corrected within 18 hours after pack placement and aggressive resuscitation. We concluded that the onset of nonmechanical bleeding and a coagulopathy marks a grave prognosis for the patient, and consideration should be given at this time for pack placement. Patients can then be aggressively resuscitated and returned to the operating room within 24 hours for pack removal if stability is achieved.
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PMID:Benefits of intra-abdominal pack placement for the management of nonmechanical hemorrhage. 229 76

Additive red blood cells (RBCs) have replaced packed RBCs for treatment of massive hemorrhage in many medical centers. Modifications in transfusion apparatus and RBC viscosity were tested for their ability to provide rapid flow of additive RBCs. Infusions through standard transfusion tubing and three types of large-bore transfusion tubing were compared using three large-bore catheters, two infusion pressures, and additive RBCs of three different viscosities. More than 13 minutes were required to infuse 1 unit 4 C RBCs using current accepted practice (16-gauge catheter, standard tubing, gravity flow). The most rapid technique resulted in an infusion time of 20 +/- 1 seconds for 22 C blood. The addition of pressure infusion, large-bore tubing, or an 8F catheter to a transfusion system reduced infusion times up to 74%, 82%, and 85%, respectively. The combination of all three techniques resulted in a maximum improvement of 96%. Saline predilution and warming did not consistently provide clinically important differences in infusion time but may be important for avoidance of hypothermia. Spectrophotometric measurement of free hemoglobin demonstrated no clinically significant hemolysis secondary to rapid infusion. Clinical management should address potential hypocalcemia and coagulopathy. We conclude that large-bore tubing, pressure infusion, and an 8F catheter can provide important decreases in infusion time of additive RBCs without evidence of significant hemolysis.
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PMID:Rapid infusion of additive red blood cells: alternative techniques for massive hemorrhage. 239 76

Subclinical plasma coagulation during cardiopulmonary bypass has been associated with marked platelet and clotting factor consumption in monkeys. To better define subclinical coagulation in man, we measured plasma fibrinopeptide A concentrations before, during, and after cardiopulmonary bypass. Patients were assigned to one of three groups of heparin management: group 1 (n = 10)--initial heparin dose 300 IU/kg, with supplemental heparin if the activated coagulation time fell below 400 seconds; group 2 (n = 6)--initial heparin dose 250 IU/kg, with supplemental heparin if activated coagulation time was less than 400 seconds; and group 3 (n = 5)--initial heparin dose 350 to 400 IU/kg, with supplemental heparin if whole blood heparin concentration was less than or equal to 4.1 IU/ml. Activated coagulation time and heparin concentration were measured every 30 minutes during cardiopulmonary bypass, and fibrinopeptide A was measured at hypothermia, normothermia, and whenever activated coagulation time was less than 400 seconds. Quantitative and qualitative blood clotting competence was assessed after cardiopulmonary bypass, including mediastinal drainage for the first 24 hours. Fibrinopeptide A values were markedly elevated during cardiopulmonary bypass but were well below the levels present before and after cardiopulmonary bypass. Fibrinopeptide A correlated inversely with heparin concentration during cardiopulmonary bypass (r = -0.46, p = 0.03), but higher fibrinopeptide A levels during cardiopulmonary bypass did not correlate with post-cardiopulmonary bypass coagulopathy. Group 3 patients received the highest heparin doses (p less than 0.05) and had the greatest postoperative blood loss (p less than 0.05). Protamine dose and heparin concentration during cardiopulmonary bypass correlated best with postoperative mediastinal drainage. Our findings support the following conclusions: (1) compensated subclinical plasma coagulation activity occurs during cardiopulmonary bypass despite activated coagulation time greater than 400 seconds or heparin concentration greater than or equal to 4.1 IU/ml; (2) post-cardiopulmonary bypass mediastinal drainage correlates strongly with increased heparin concentration during cardiopulmonary bypass (p less than 0.05) and protamine dose (p less than 0.05); and (3) during cardiopulmonary bypass at both normothermia and hypothermia, activated coagulation times greater than 350 seconds result in acceptable fibrinopeptide A levels and post-cardiopulmonary bypass blood clotting.
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PMID:Heparin dosing and monitoring for cardiopulmonary bypass. A comparison of techniques with measurement of subclinical plasma coagulation. 230 70


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