Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Rewarming”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 721 records · Page 40Linked to original sources
PubMed1996

Thermography of hands after a radial forearm flap has been raised.

To evaluate possible circulatory changes in the donor hand 18 patients underwent cold stress testing and thermography of both hands a mean of 13 months after a radial forearm flap had been harvested. Temperatures were measured with a computed Inframetrics 600L infrared thermocamera, and the images were videotaped at room temperature and after a cold challenge (immersion in a water bath at 15 degrees C for five minutes). Temperatures were measured on the volar aspect of each fingertip, and rewarming curves were plotted for both hands. The patients could be divided into three groups according to the rewarming pattern: mean temperature of the donor hand was more than 0.5 degree C warmer than that of the other hand (n = 7), rewarming was similar in both hands (n = 6), and the mean temperature of the donor hand was less than 0.5 degree C colder than that of the other hand (n = 5). Patients with a colder donor hand had significantly wider (Pearson's r = 0.62, p = 0.005) and longer (r = 0.71, p = 0.001) defects. The rewarming pattern did not correlate with subjective cold intolerance, but the temperature of the donor hand was a mean of 0.5 degree C less than that of the other hand in room temperature in subjects who experienced cold intolerance (p = 0.019). We conclude that the raising of a radial forearm flap, particularly a large one, affects the thermoregulatory system of the donor hand, results in abnormal rewarming, and can cause subjective cold intolerance.

Adult↗
PubMed2002

Intraoperative mild hypothermia therapy in patients scheduled for neurosurgical procedures.

BACKGROUND: Deliberate mild hypothermia has been proposed as a means of providing cerebral protection during neurosurgicals procedures complicated by cerebral ischaemia. Our prospective study was designed to examine the safety of deliberate mild hypothermia and to evaluate our techniques for cooling and rewarming. MATERIALS AND METHODS: With institutional approval, 20 patients scheduled for elective neurosurgery were enrolled into our prospective study. After the induction of anaesthesia, the core temperature was measured by urinary catheters with probes (Kendall). The patients were cooled (temperature of blankets set at 15 degrees C) and rewarmed (temperature set at 40 degrees C) by two circulating water blankets (Blanketrol III, Cincinnati Sub-Zero, Cincinnati). The variables are expressed as a mean +/- standard deviation. RESULTS: The time of anaesthesia was 316+/-53 min. The core temperature was 36.5+/-0.4 degrees C at the start of anaesthesia. The minimal temperature reached 34.4+/-0.4 degrees C. The patients were cooled at a rate of 1.1+/-0.3 degrees C/h and rewarmed at a rate of 0.9+/-0.4 degrees C/h. The temperature was 35.8+/-0.5 degrees C after the neurosurgical procedure. Deliberate mild hypothermia with rewarming did not cause delays in emerging from anaesthesia. On the control CT scan, no ischaemic changes were observed after surgery. CONCLUSIONS: Our findings indicate that patients can be cooled and rewarmed by two circulating water blankets, and core temperatures about 34 degrees C were easily achieved. The deliberate mild hypothermia is together with careful anaesthesia management a safe technique of cerebral protection from ischaemic insult during elective neurosurgical procedures. (Tab. 1, Ref. 11.).

Brain Ischemia↗
PubMed1992

Cardiopulmonary bypass for resuscitation of patients with accidental hypothermia and cardiac arrest.

Hypothermic patients have been successfully rewarmed by a number of methods. However, when cardiac arrest occurs, as it frequently does at core temperatures of less than 27 degrees C, prolonged cardiopulmonary resuscitation (CPR) is required, because defibrillation can rarely be achieved until the patient has been rewarmed to 30 degrees to 34 degrees C. Five cases of accidental hypothermia with cardiac arrest treated with cardiopulmonary bypass are discussed. The first patient died as a result of inadequate low-flow cardiopulmonary bypass by the femorofemoral route. The second patient had prolonged CPR by closed-chest cardiac massage and warm peritoneal lavage followed by transthoracic cardiopulmonary bypass. This patient regained consciousness but was found to be paraplegic and died from bowel infarction related to peritoneal rewarming without adequate perfusion. In the last three patients, high-flow cardiopulmonary bypass was rapidly achieved using a no. 28 French chest tube for femoral venous cannulation, and they recovered completely. In cases of accidental hypothermia with cardiac arrest, rapid institution of full cardiopulmonary bypass provides excellent circulatory support and rapid rewarming. This avoids the complications of prolonged inadequate circulation that occur when closed-chest cardiac massage and external rewarming are used.

Adult↗
PubMedDate not supplied

New determinants for tolerance of coffee (Coffea arabica L.) seeds to liquid nitrogen exposure.

The present work establishes for the first time that tolerance of coffee seeds to liquid nitrogen (LN) exposure depends on the initial quality of the seedlot and on the rewarming regime employed. Seedlot quality was estimated by the parameters of a quantal response model of desiccation sensitivity developed previously. The percentage of seedlings recovered from cryopreserved seeds was very well correlated with the relative humidity (RH) at which 90 percent of the initial viability was retained, RH90, as estimated by the model. Whatever the cooling regime employed, rewarming the seeds slowly by exposing them to ambient air was highly detrimental. Slow rewarming-induced viability loss was not due to imbibitional damage since seeds pre-heated at 37 degree C after slow rewarming to 0 degree C exhibited a survival percentage lower than seeds thawed rapidly to 0 degree C before sowing. The optimal hydration status for coffee seed cryopreservation was also re-examined. Drying seeds in 81 percent RH provided survival percentages considerably higher than those obtained using the drying RH always employed until now, i.e. 78 percent. A new procedure for slowly precooling the seeds prior to immersion in LN was also established. It consisted of placing the vials containing the seeds in a dry ice-bath for 25 min. Using this procedure in combination with seed drying in 81 percent RH and rapid rewarming in a 37 degree C water-bath for 30 min ensured the highest survival percentages ever obtained with coffee seeds, i.e. 89 percent, a value which was not significantly different from the initial viability percentage.

Coffea↗
PubMed1988

Correction of hypothermia by continuous pleural perfusion.

Hypothermia to less than 30 degrees C is associated with significant harmful effects, including ventricular fibrillation. None of the currently used techniques for core rewarming is entirely satisfactory. Continuous perfusion of the pleural space with warm saline solution has been studied as a method of core rewarming. Pigs were cooled to 28 degrees to 30 degrees C. The pleural space was continuously perfused with fluid at a temperature of 42 degrees C. Five hypothermic control pigs did not achieve a temperature of 32 degrees C in 3 hours of spontaneous rewarming. The rise in 1 hour was 0.34 degrees C. In 10 pigs that underwent continuous pleural perfusion the temperature exceeded 32 degrees C in a mean time of 56 minutes. The rise in temperature in the first hour of rewarming was 5.05 degrees C. Continuous pleural perfusion is a rapid and effective technique for core rewarming of the hypothermic pig.

Animals↗
PubMed1986

Accidental severe hypothermia.

Accidental hypothermia is a health problem with a scope which has been underestimated by the medical community. Limited awareness and limited diagnostic equipment, along with hospital coding inaccuracies, make calculation of the true number of instances of accidental hypothermia nearly impossible. Severe hypothermia occurs when body temperature falls below 28 degrees C. The patient may be unconscious, with such severely depressed vital signs that he appears to be dead. All such patients, regardless of extremis upon presentation, should undergo vigorous cardiopulmonary resuscitation in addition to rewarming, because a reliable determination of death is nearly impossible without the restoration of body temperature. Rewarming must follow the implementation of adequate cardiovascular support, maintaining serum acid base balance, arterial oxygenation and intravascular volume levels within the appropriate physiologic ranges; otherwise, the reawakening of metabolic needs will outpace the recovery of cardiac function, and the patient will die of multiple organ infarction. In addition, standard mechanical or manual CPR can furnish adequate cardiovascular support for the severely failing myocardium. When cardiovascular resuscitation is performed first, followed by rewarming with a continual maintenance of optimum cardiovascular function, then all standard methods of rewarming (external rewarming with a fluid-circulated blanket, peritoneal lavage or partial cardiac bypass) should give equally good results. The preceding guidelines are extrapolated from a retrospective review of available clinical material as well as controlled prospective animal studies. Prospective clinical studies should be performed to confirm the acceptability of these guidelines; an inter-institutional study may be the best way to glean such data and should be considered by researchers interested in this problem.

Accidents↗
PubMed1985

Fluid replacement during hypothermia.

Hypothermia produces acidosis, depressed cardiac function, hypovolemia and hypotension. This study was designed to examine the cardiovascular dynamics involved with restoration of the hypovolemia before rewarming. Mixed breed splenectomized adult dogs (n = 16) were anesthetized with pentobarbital and cooled to a right atrial temperature of 25 degrees C at a rate of 3 degrees C X h-1. The animals were maintained at 25 degrees C for 6 h and rewarmed at 3 degrees C X h-1. Group 1 was given no fluid, Group 2 was given saline (20% of plasma volume infused in 10 min). 2 h after reaching 25 degrees C and Group 3 received saline just prior to rewarming. The hematocrit was elevated in all groups (p less than 0.05) upon cooling, but did not differ between groups even after saline was given. Cardiac output (Co) at 25 degrees C was 35% of precooled values. Group 2 increased their Q by 15% with fluid and this Q was maintained at higher levels than Groups 1 or 3 for the next 4 h. Plasma volume, heart rate, and cardiac contractility returned to control levels upon rewarming, but Q remained low (less than 10%). The level of Q at the start of rewarming did not affect the final level of Q.

Acid-Base Equilibrium↗
PubMed1980

Accidental hypothermia treated without mortality.

Accidental hypothermia, a core temperature below 34 degrees C., is frequently fatal, particularly in the ill and elderly. Traditional treatment methods result in reported mortalities of between 45 and 100 per cent. Despite these terrible statistics, advocates of slow rewarming persist. They cite the shock and vascular collapse which can occur with peripheral dilation as reasons to avoid rapid external rewarming. Isolated successes using internal core rewarming, such as hemodialysis or cardiopulmonary bypass, are spectacular but not practical in the usual clinical situation. By combining methods used for the resuscitation of burn injury with the treatment principles for frostbite, a highly effective treatment protocol results. Agressive fluid resuscitation, rapid immersion rewarming and careful systematic monitoring have been used to treat ten consecutive patients without a single death. Concomitant problems of alcoholism, stroke, myxedema, tuberculosis and paraplegia were also treated. Rapid external rewarming by immersion can result in a low mortality in patients with severe hypothermia.

Acidosis↗
PubMed1997

Brain cooling efficiency with pH-stat and alpha-stat cardiopulmonary bypass in newborn pigs.

BACKGROUND: For infant cardiac surgery, recent studies suggest improved neurological outcome after deep hypothermic circulatory arrest when pH-stat cardiopulmonary bypass is used compared with alpha-stat cardiopulmonary bypass. The pH-stat method is hypothesized to protect the brain through improved cooling and/or rewarming. We examined brain cooling and rewarming during pH-stat and alpha-stat cardiopulmonary bypass in 12 newborn pigs. METHODS AND RESULTS: Microthermistors were inserted into the caudate and cortical gray and white matter, and a cranial window was created to map neocortical temperature gradients by using infrared imaging. Piglets were cooled with pH-stat or alpha-stat cardiopulmonary bypass until all brain regions were less than 20 degrees C; then they were subjected to 60 minutes of circulatory arrest, and afterward, rewarmed with cardiopulmonary bypass. During cardiopulmonary bypass cooling, cortical gray and white matter and caudate temperatures were up to 5 degrees C less in pH-stat than in alpha-stat (P<.05), although after 10 minutes of cooling, only cortical white matter temperature remained significantly less in pH-stat. Neocortical thermal gradients during cardiopulmonary bypass cooling were greater in pH-stat versus alpha-stat during the initial 8 minutes (4 degrees C to 5 degrees C versus 2 degrees C to 3 degrees C, P<.01) but were less by 18 to 20 minutes (0.9 degrees C versus 1.7 degrees C, P<.01). Cardiopulmonary bypass cooling time to less than 20 degrees C was shorter for pH-stat than for alpha-stat in cortical gray matter (14 versus 17 minutes, P<.05) and cortical white matter (17 versus 23 minutes, P<.001) but not in caudate (13 versus 16 minutes, P=NS). Cooling time to less than 1 degrees C neocortical thermal gradient was shorter in pH-stat than in alpha-stat (15 versus 23 minutes, P<.001). During rewarming, regional brain temperatures and neocortical thermal gradients were not different between groups. CONCLUSIONS: pH-stat improves brain cooling efficiency during cardiopulmonary bypass because all regions cooled more rapidly, especially cortical white matter, and less time was required to achieve uniform cerebral deep hypothermia. pH-stat and alpha-stat cardiopulmonary bypass rewarm the brain similarly after deep hypothermic arrest.

Animals↗
PubMed1998

ATP-sensitive potassium channel activation before cardioplegia. Effects on ventricular and myocyte function.

BACKGROUND: Pretreatment with potassium channel openers (PCOs) has been shown to provide protective effects in the setting of myocardial ischemia. The goal of the present study was to examine whether PCO pretreatment would provide protective effects on left ventricular (LV) and myocyte function after cardioplegic arrest. METHODS AND RESULTS: The first study quantified the effects of PCO pretreatment on LV myocyte contractility after simulated cardioplegic arrest. LV porcine myocytes were randomly assigned to 3 groups: (1) normothermic control: 37 degrees C x 2 hours (n = 116); (2) cardioplegia: K+ 24 mEq/L, 4 degrees C x 2 hours followed by reperfusion and rewarming (n = 62); and (3) PCO/cardioplegia: 5 minutes of PCO treatment (50 mumol/L, SR47063, 37 degrees C; n = 94) followed by cardioplegic arrest and rewarming. Myocyte contractility was measured after rewarming by videomicroscopy. The second study determined whether the effects of PCO pretreatment could be translated to an in vivo model of cardioplegic arrest. Pigs (weight 30 to 35 kg) were assigned to the following: (1) cardioplegia: institution of cardiopulmonary bypass (CPB) and cardioplegic arrest (K+ 24 mEq/L, 4 degrees C x 2 hours) followed by reperfusion and rewarming (n = 8); and (2) PCO/cardioplegia: institution of CPB, antegrade myocardial PCO perfusion without recirculation (500 mL of 50 mumol/L, SR47063, 37 degrees C), followed by cardioplegic arrest (n = 6). LV function was examined at baseline (pre-CPB) and at 0 to 30 minutes after separation from CPB by use of the preload-recruitable stroke work relation (PRSWR; x 10(5) dyne.cm/mm Hg). LV myocyte velocity of shortening was reduced after cardioplegic arrest and rewarming compared with normothermic control (37 +/- 3 vs 69 +/- 3 microns/s, P < 0.05) and was improved with 5 minutes of PCO treatment (58 +/- 3 microns/s). In the intact experiments, the slope of the PRSWR was depressed in the cardioplegia group compared with baseline with separation from CPB (1.07 +/- 0.15 vs 2.57 +/- 0.11, P < 0.05) and remained reduced for up to 30 minutes after CPB. In the PCO-pretreated animals, the PRSWR was higher after cessation of CPB when compared with the untreated cardioplegia group (1.72 +/- 0.07, P < 0.05). However, in the PCO pretreatment group, 50% developed refractory ventricular fibrillation by 5 minutes after CPB, which prevented further study. CONCLUSIONS: PCO pretreatment improved LV myocyte contractile function in an in vitro system of cardioplegic arrest. The in vivo translation of this improvement in contractile performance with PCO pretreatment was confounded by refractory arrhythmogenesis. Thus the application of PCO pretreatment as a protective strategy in the setting of cardiac surgery may be problematic.

Adenosine Triphosphate↗
PubMed2000

Restoration of body temperature to normothermia during resuscitation following trauma-hemorrhage improves the depressed cardiovascular and hepatocellular functions.

HYPOTHESIS: Rewarming the body to 37 degrees C during resuscitation following trauma-hemorrhage has salutary effects on cardiovascular and hepatocellular functions. DESIGN, INTERVENTIONS, AND MAIN OUTCOME MEASURES: Male rats underwent laparotomy (trauma induced) and were then bled to and maintained at a mean arterial pressure of 40 mm Hg until 40% of the maximum shed blood volume was returned in the form of Ringer lactate solution. Rats were exposed to ambient temperature and allowed to become hypothermic during hemorrhage. The animals were then resuscitated with 4 times the volume of shed blood with Ringer lactate solution for 60 minutes. In 1 group, the body temperature was rewarmed to 37 degrees C during resuscitation. In another group, the body temperature was maintained at hypothermia (32 degrees C) for 4 hours after resuscitation. In an additional group, the body temperature was kept at 37 degrees C during hemorrhage and resuscitation. At 4 hours after resuscitation, the rats were returned to a room with ambient temperature. Various in vivo heart performance variables (maximal rate of pressure increase and decrease), cardiac output, hepatocellular function, and plasma IL-6 level were determined at 24 hours after resuscitation. RESULTS: Either maintenance of normothermia during hemorrhage or prolonged hypothermia following resuscitation had deleterious effects on cardiovascular variables and hepatocellular function and up-regulated plasma IL-6 levels. In contrast, rewarming the body to 37 degrees C during resuscitation improved cardiac contractility, cardiac output, and hepatocellular function and reduced plasma IL-6 level. CONCLUSION: Since rewarming the body temperature to normothermia during resuscitation improved depressed cardiovascular and hepatocellular functions, this should be considered as a useful adjunct to fluid resuscitation after trauma-hemorrhage.

Animals↗
PubMed1995

The management of temperature during hypothermic cardiopulmonary bypass: I--Canadian survey.

During hypothermic cardiopulmonary bypass (CPB) patients are cooled, usually to between 30-32 degrees C, and, after myocardial blood flow is restored, they are rewarmed with blood heated in the pump-oxygenator. We audited our local practice by recording tympanic and nasopharyngeal temperatures in 11 patients undergoing hypothermic CPB. We found that, during rewarming, nasopharyngeal and tympanic temperatures commonly exceeded 38 degrees C although temperature measured in the bladder was < 37 degrees C. A survey of cardiac surgery centres in Canada suggested that most centres induce hyperthermia in highly perfused tissues during rewarming, sometimes inadvertently. This may be of some importance because it has become widely appreciated by neuroscientists that mild degrees of brain cooling (2-5 degrees C) are capable of conferring dramatic protection from ischaemic brain injury and, conversely, mild temperature elevation may be markedly deleterious. If control of brain temperature is considered desirable then we would suggest that nasopharyngeal temperature be monitored during rewarming on CPB.

Adult↗
PubMed1995

The management of temperature during hypothermic cardiopulmonary bypass: II--Effect of prolonged hypothermia.

In animals mild hypothermia (32-35 degrees C) reduces ischaemic brain injury, but this has not been investigated in humans. During hypothermic cardiopulmonary bypass (CPB) patients are made hypothermic (usually to 30-32 degrees C) but are then rewarmed at a time when they are still at risk of ischaemic brain injury. We investigated the feasibility and safety of maintaining mild hypothermia throughout the CPB period. Thirty adult cardiac surgical patients were randomized to either rewarming to 36-37 degrees C or to maintaining temperature at 34 degrees C without rewarming. On arrival in the recovery room, patients in the hypothermic group had a mean bladder temperature of 33.8 +/- 0.45 degrees C compared with 35.4 +/- 0.58 degrees C (mean +/- SD, P < 0.05) in the rewarmed patients. There were no differences between groups in intra- or postoperative blood loss or blood use, inotrope use, dysrhythmias, or myocardial infarction. The hypothermic group received more muscle relaxant for the treatment of shivering postoperatively. Our results suggest that mild hypothermia following CPB did not increase morbidity although larger studies are needed for confirmation.

Adult↗
PubMed1996

The effects of forced-air warming on postbypass central and skin temperatures and shivering activity.

STUDY OBJECTIVE: To test the hypothesis that forced-air skin-surface warming used prophylactically after hypothermic cardiopulmonary bypass (CPB) would: (1) decrease the incidence and severity of postbypass shivering, (2) rapidly increase skin-surface temperatures when compared with standard warmed cotton blankets, and (3) not contribute to excessive central temperature elevation. DESIGN: Prospective, randomized, nonblinded comparison of two rewarming techniques. SETTING: Multidisciplinary intensive care unit at a tertiary care, private teaching hospital. PATIENTS: Following hypothermic CPB, 47 patients underwent postoperative rewarming by using either conduction (warmed cotton blankets) or convection (forced-air cover) techniques. MEASUREMENTS AND MAIN RESULTS: Central and skin temperatures were measured at 30-minute intervals for 5.5 hours postoperatively. Four lead electromyographic recordings were used to objectively document shivering activity. Antihypertensives, opioids, sedatives, and muscle relaxants were administered per patient need and recorded. The forced-air cover markedly decreased the overall incidence, duration, and magnitude of significant shivering compared with the warmed cotton blankets. Forced-air therapy produced clinically significant increases in skin surface temperatures, but avoided excessive central temperature elevation when compared with passive rewarming with cotton blankets. CONCLUSION: Convection warming, when compared with conductive warming with cotton blankets, limited the incidence, magnitude, and duration of shivering following hypothermic cardiac surgery. This suggests an important role of cutaneous thermal input in the mediation of the shivering response. The central tissue compartment is buffered from the effects of skin-surface warming and, thus, forced-air therapy will not lead to excessive central temperature elevation in this patient population when compared with cotton blanket rewarming.

Aged↗
PubMed2004

Hemodilution elevates cerebral blood flow and oxygen metabolism during cardiopulmonary bypass in piglets.

BACKGROUND: Hemodilution continues to be widely used during cardiopulmonary bypass (CPB) for both adults and children. Previous studies with nonbypass models have suggested that an increase in cerebral blood flow (CBF) compensates for the reduced oxygen-carrying capacity; however, this increased CBF is achieved by an increase in cardiac output. We hypothesized that even with the fixed-flow perfusion of CPB, CBF would be increased during hemodilution. METHODS: Two experiments were conducted and analyzed separately. In each experiment, 10 piglets were randomized to two different groups, one with a total blood prime yielding a high hematocrit (25% or 30%), and the other with a crystalloid prime resulting in a low hematocrit (10% or 15%). Animals were cooled with pH-stat strategy at full flow (100 or 150 mL.kg(-1).min(-1)) to a nasopharyngeal temperature of 15 degrees C, a period of low flow (50 mL.kg(-1).min(-1)) preceding deep hypothermic circulatory arrest (45 or 60 minutes), and a period of rewarming at full flow. Cerebral blood flow was measured at the beginning of CPB, at the end of cooling, at the end of low flow, 5 minutes after the start of rewarming, and at the end of rewarming by injection of radioactive microspheres. RESULTS: Mean arterial pressure was significantly greater with higher hematocrit at each time point (p< 0.05). Cerebral blood flow and the cerebral metabolic rate of oxygen decreased during cooling and further during low flow bypass but were significantly greater with lower hematocrit during mild hypothermia and at the end of rewarming (p< 0.05). CONCLUSIONS: Hemodilution is associated with decreased perfusion pressure, increased CBF and increased the cerebral metabolic rate of oxygen during hypothermic CPB.

Animals↗
PubMed2004

Myocyte contractility with caspase inhibition and simulated hyperkalemic cardioplegic arrest.

BACKGROUND: Exposure of left ventricular (LV) myocytes to simulated hyperkalemic cardioplegic arrest (HCA) has been demonstrated to perturb ionic homeostasis and adversely affect myocyte contractility on rewarming. Altered ionic homeostasis can cause cytosolic activation of the caspases. While caspases participate in apoptosis, these proteases can degrade myocyte contractile proteins, and thereby alter myocyte contractility. Accordingly, this study tested the hypothesis that caspase inhibition during HCA would attenuate the degree of myocyte contractile dysfunction upon rewarming, independent of a loss in myocyte viability. METHODS: Porcine (n = 8) LV myocytes were isolated and assigned to the following treatment groups: normothermic control: incubation in cell culture media for 2 hours at 37 degrees C; HCA only: incubation for 2 hours in hypothermic HCA solution (4 degrees C, 24 mEq K(+)); or incubation in hypothermic HCA solution supplemented with 10 microM of the caspase inhibitor, z-VAD (z-Val-Ala-Asp-fluoromethyl-ketone, HCA+zVAD). Myocyte viability, assayed as a function of mitochondrial function, was determined to be similar in the normothermic and both HCA groups. RESULTS: The HCA caused a significant reduction in myocyte shortening velocity compared with normothermic control values (41 +/- 6 versus 86 +/- 8 microm/s, p < 0.05). The HCA+zVAD group had significantly improved myocyte shortening velocity compared with the HCA only group (63 +/- 7 microm/s, p < 0.05). CONCLUSIONS: Independent of changes in viability, caspase inhibition attenuated myocyte contractile dysfunction after HCA and rewarming. Thus, caspase activation during HCA contributes, at least in part, to impaired myocyte contractility with rewarming. Supplementation of HCA with caspase inhibitors may provide a means to preserve myocyte contractile function after cardioplegic arrest.

Amino Acid Chloromethyl Ketones↗
PubMed2006

The effect of temperature on the QTc interval in the newborn infant receiving extracorporeal membrane oxygenation (ECMO).

OBJECTIVE: To explore the changes in the QTc interval during mild hypothermia in neonates receiving extracorporeal membrane oxygenation (ECMO). DESIGN: Twenty seven neonates (median gestation 40 weeks; range 33-41 weeks) enrolled in a pilot study of mild hypothermia were studied during the first five days of ECMO. The first group (N=7) were maintained at 37 degrees C throughout the study period. Subsequent groups (N=5) were cooled to 36 degrees C, 35 degrees C and 34 degrees C respectively for twenty four hours and the final group to 34 degrees C for forty eight hours before being rewarmed to 37 degrees C. Using a 24 h digital monitor, the QT and QTc intervals were recorded continuously during the cooling and rewarming period and validated using standard 12 lead electrocardiograms. Patients were carefully assessed clinically and routine biochemistry (including magnesium and calcium) laboratory tests measured pre ECMO and at timed intervals during cooling and rewarming. RESULTS: The mean difference between the continuous digital and 12 lead ECG values for QTc was -13.3 ms. During the first 24 h of cooling, the mean (95th centile) values for the digitally measured QTc interval at 37 degrees C=431(506) milliseconds (ms); 36 degrees C=459(521) ms; 35 degrees C=445(516) ms; 34 degrees C=465(531) ms; 34 degrees C for 48 h=466(521) ms. During this period overall QTc increased by 3.12 ms (95% confidence intervals 6.17 to 0.84; p=0.04) for each degree fall in body temperature. During rewarming, there was no significant relationship between QTc and temperature change. No serious arrhythmias were during cooling. Using univariate analysis, no relationship was found between QTc and electrolytes, heart rate and blood pressure. CONCLUSIONS: QTc shows significant variability in individuals, and only a small proportion of this can be explained by rectal temperature. Mild hypothermia was not associated with serious cardiac arrhythmias.

Body Temperature↗
PubMed2005

Thoracic lavage in accidental hypothermia with cardiac arrest--report of a case and review of the literature.

BACKGROUND: Accidental hypothermia resulting in cardiac arrest poses numerous therapeutic challenges. Cardiopulmonary bypass (CPB) should be used if feasible since it optimally provides both central rewarming and circulatory support. However, this modality may not be available or is contraindicated in certain cases. Thoracic lavage (TL) provides satisfactory heat transfer and may be performed by a variety of physicians. This paper presents the physiological rationale, technique, and role for TL in accidental hypothermia with cardiac arrest. METHODS: A patient with hypothermic cardiac arrest, treated by the author using TL, serves as the basis for this report. A search of the English language literature using PubMed (National Library of Medicine, Bethesda, Maryland) was conducted from 1966 to 2003 and 13 additional patients were identified. Demographic information, lavage method, rewarming rate, complications, and neurological outcome were analysed. RESULTS: There were numerous causes for hypothermia, with drug and alcohol intoxication being the most common (n = 4; 28.6%). Patient age ranged from 8 to 72 years (median = 36 years). Mean core temperature was 24.5+/-0.60 degrees C. Most patients were without blood pressure or pulse upon presentation to the Emergency Department and the predominant cardiac rhythm was ventricular fibrillation (VF) (n = 9; 64.3%). Thoracic lavage was accomplished by thoracotomy in seven patients and tube thoracotomy in the remaining seven. Median rewarming rate was 2.95 degrees C/h. Median time until sinus rhythm was restored was 120 min. Median length of hospital stay was 2 weeks. Four (28.6%) patients died. Complications were seen in 12 (85.7%) patients. Among survivors, neurological outcome was normal in 8 (80%) while two were left with residual impairments. CONCLUSIONS: Patients presenting in cardiac arrest from accidental hypothermia may be rewarmed effectively using TL. Among survivors, normal neurological recovery is seen. Thoracic lavage should be strongly considered for these patients if CPB is not available or contraindicated.

Adult↗