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Gastroschisis: a 17-year experience.

From 1970 to 1987, 23 neonates with gastroschisis were treated at Kobe Children's Hospital. One patient died and 22 survived (96%). Seven patients were hypothermic upon arrival at the hospital, with body temperatures of 31.8 to 35.4 degrees C. Six patients were successfully managed by warm saline bathing (40 to 42 degrees C for one minute) to improve hypothermia. One patient who did not receive this rewarming procedure (body temperature, 31.8 degrees C) died of intractable metabolic disorders related to hypothermia. Ten patients were treated by primary fascial closure of the abdominal wall defect, eight by the skin flap method with secondary closure of the deliberately created abdominal hernia, and five by the silastic sac technique. Two patients required creation of intestinal stomas for ileal atresia. After surgery, 19 patients required ventilatory care with total paralysis (average 6.0 days). Nine patients required total parenteral nutrition (TPN), while 13 tolerated enteral feeding on days 3 to 11 (average, 6.0 days). In the latter 13 patients, intravenous fluid therapy was discontinued on day 11. Our experience suggests that (1) rewarming in a saline bath is effective treatment for hypothermia, (2) ventilatory assistance with total paralysis is mandatory, and (3) TPN can be avoided in 60% of the patients.

Abdominal Muscles↗

The dynamic air bubble trap reduces cerebral microembolism during cardiopulmonary bypass.

OBJECTIVE: Neuropsychologic disorders are common after coronary artery bypass operations. Air microbubbles are identified as a contributing factor. A dynamic bubble trap might reduce the number of gaseous microemboli. METHODS: A total of 50 patients undergoing coronary artery bypass operation were recruited for this study. In 26 patients a dynamic bubble trap was placed between the arterial filter and the aortic cannula (group 1), and in 24 patients a placebo dynamic bubble trap was used (group 2). The number of high-intensity transient signals within the proximal middle cerebral artery was continuously measured on both sides during bypass, which was separated into 4 periods: phase 1, start of bypass until aortic clamping; phase 2, aortic clamping until rewarming; phase 3, rewarming until clamp removal; and phase 4, clamp removal until end of bypass. S100 beta values were measured before, immediately after, and 6 and 48 hours after the operation and before hospital discharge. RESULTS: The bubble elimination rate during bypass was 77% in group 1 and 28% in group 2 (P <.0001). The number of high-intensity signals was lower in group 1 during phase 1 (5.8 +/- 7.3 vs 16 +/- 15.4, P <.05 vs group 2) and phase 2 (6.9 +/- 7.3 vs 24.2 +/- 27.3, P <.05 vs group 2) but not during phases 3 and 4. Serum S100 beta values were equally increased in both groups immediately after the operation. Group 2 patients had higher S100 beta values 6 hours after the operation and significantly higher S100 beta values 48 hours after the operation (0.06 +/- 0.14 vs 0.18 +/- 0.24, P =.0133 vs group 2). Age and S100 beta values were correlated in group 2 but not in group 1. CONCLUSION: Gaseous microemboli can be removed with a dynamic bubble trap. Subclinical cerebral injury detectable by increases of S100 beta disappears earlier after surgical intervention.

Aged↗

Conditioned blood reperfusion markedly enhances neurologic recovery after prolonged cerebral ischemia.

OBJECTIVES: To determine whether controlled reperfusion using conditioned leukodepleted blood can substantially limit cerebral reperfusion injury following prolonged ischemia. METHODS: Eighteen pigs (25-35 kg) underwent 90 minutes of hypothermic circulatory arrest (19 degrees C) to produce brain ischemia. At the start of rewarming, 10 pigs received uncontrolled reperfusion with unmodified (normal) blood. The other 8 pigs underwent 10 minutes of controlled reperfusion by selectively perfusing both common carotid arteries with blood passed through a CoBRA filter. This filter conditions the blood by removing white blood cells, platelets, and attenuating complement. Two other pigs underwent cooling and rewarming only (controls) without ischemia. Neurologic assessment was done using neurologic deficit scoring (0 = normal, 500 = brain death), and jugular venous samples were obtained for biochemical analysis postreperfusion. RESULTS: There were no statistical differences in hemodynamics between groups. At 6 hours postanesthesia, all animals receiving normal blood were substantially neurologically impaired. At 24 hours, they all had abnormal positioning and all but 1 were unable to sit or stand (neurologic score 124 +/- 19). In contrast, nonischemic controls and pigs receiving conditioned blood reperfusion showed only minor neurologic deficits at 6 hours, and at 24 hours all were considered normal (neurologic scores 0 and 6 +/- 5; P <.005 vs uncontrolled reperfusion). Compared with pigs receiving normal blood reperfusion, oxygen free radical formation (conjugated dienes 1.70 +/- 0.03 vs 1.60 +/- 0.02 Abs 240 nm; P <.05 vs uncontrolled reperfusion), and endothelin-1 release (2.12 +/- 0.09 vs 1.84 +/- 0.06 pg/mL; P <.05 vs uncontrolled reperfusion) were also significantly lower in animals receiving conditioned blood. CONCLUSIONS: Following prolonged cerebral ischemia, reperfusion injury is avoided by delivering conditioned blood, which is devoid of white cells, platelets, and membrane attack complex. These results suggest that this modality is clinically useful in situations where the brain is subjected to prolonged ischemia.

Animals↗

Profound systemic hypothermia inhibits the release of neurotransmitter amino acids in spinal cord ischemia.

Profound hypothermia induced with cardiopulmonary bypass has a protective effect on spinal cord function during operations on the thoracoabdominal aorta. The mechanism of this protection remains unknown. It has been proposed that the release of excitatory amino acids in the extracellular space plays a causal role in irreversible neuronal damage. We investigated the changes in extracellular neurotransmitter amino acid concentrations with the use of in vivo microdialysis in a swine model of spinal cord ischemia. All animals underwent left thoracotomy and right atrium-femoral artery cardiopulmonary bypass with additional aortic arch perfusion. Lumbar laminectomies were then done and microdialysis probes were inserted stereotactically in the anterior horn of the second and fourth segments of the lumbar spinal cord. The probes were perfused with artificial cerebrospinal fluid at a rate of 2 microliters/min and 15-minute samples were assayed by high-performance liquid chromatography. Group 1 animals (n = 6) underwent aortic clamping distal to the left subclavian artery and proximal to the renal arteries for 60 minutes at normothermia (37 degrees C) and group 2 animals (n = 5) were cooled to a rectal temperature of 20 degrees C before application of aortic clamps, maintained at this level during cardiopulmonary bypass until the aorta was unclamped, and then slowly rewarmed to 37 degrees C. Seven amino acids were studied, including two excitatory neurotransmitters (glutamate and aspartate) and five putative inhibitory neurotransmitters (glycine, gamma-aminobutyric acid, serine, adenosine, and taurine). Glutamate exhibited a threefold increase in extracellular concentration during normothermic ischemia compared with baseline values and remained elevated until 60 minutes after reperfusion. The increase in aspartate concentration was not significant. The extracellular concentrations of glycine and gamma-aminobutyric acid also increased significantly during ischemia and reperfusion. Hypothermia uniformly prevented the release of amino acids in the extracellular space. Glutamate levels remained significantly decreased even after rewarming to normothermia whereas glycine levels returned to baseline values. These results are consistent with a role for excitatory amino acids in the production of ischemic spinal cord injury and suggest that the mechanism of hypothermic protection may be related to decreased release of these amino acids in the ischemic spinal cord.

Analysis of Variance↗

Blood gas management and degree of cooling: effects on cerebral metabolism before and after circulatory arrest.

This study investigated the effects of different cooling strategies on cerebral metabolic response to circulatory arrest. In particular, it examined the impact of blood gas management and degree of cooling on cerebral metabolism before and after deep hypothermic circulatory arrest. Sixty-nine 1-week-old piglets (2 to 3 kg) were placed on cardiopulmonary bypass (37 degrees C) at 100 ml/kg per minute. Animals were cooled to 18 degrees or 14 degrees C as follows: alpha-stat strategy to 18 degrees C (n = 9) or 14 degrees C (n = 6), pH-stat strategy to 18 degrees C (n = 12) or 14 degrees C (n = 10). Animals underwent 60 minutes of circulator arrest followed by rewarming with alpha-stat strategy to 36 degrees C. Control animals were cooled with alpha-stat strategy to 18 degrees C (n = 10) or 14 degrees C (n = 3) and then maintained on cold cardiopulmonary bypass (100 ml/kg per minute) for 60 minutes. Three animals were excluded (see text). With the use of xenon 133 clearance methods, cerebral blood flow was measured at the following points: point I, cardiopulmonary bypass (37 degrees C); point II, cardiopulmonary bypass before circulatory arrest or control flow (18 degrees or 14 degrees C); and point III, cardiopulmonary bypass after rewarming (36 degrees C). Cerebral metabolic rate of oxygen consumption was calculated for each point. At point II, cerebral metabolism was more suppressed at 14 degrees C compared with that at 18 degrees C. At any given temperature (18 degrees or 14 degrees C), pH-stat strategy provided the greatest suppression of of cerebral metabolism. In control animals, cerebral metabolic oxygen consumption of point III returned to baseline values after 60 minutes of cold bypass. Sixty minutes of circulatory arrest resulted in a significant reduction in cerebral metabolic oxygen consumption at point III compared with that at point I regardless of cooling temperature or blood gas strategy. The amount of cerebral metabolic recovery was significantly reduced in the pH-stat 14 degrees C group compared with that in the pH-stat 18 degrees C group at point III. The use of pH-stat strategy followed by a switch to alpha-stat at 14 degrees C provided better cerebral metabolic recovery compared with either strategy used alone. The use of pH-stat strategy during initial cooling may provide the animal with maximal cerebral metabolic suppression. The cerebral acidosis produced with pH-stat cooling may worsen cerebral metabolic injury from circulatory arrest, but this affect is eliminated with the use of alpha-stat just before the period of circulatory arrest.

Animals↗

pH strategies and cerebral energetics before and after circulatory arrest.

The pH-stat strategy compared with the alpha-stat strategy provides more rapid recovery of brain high-energy phosphate stores and intracellular pH after 1 hour of hypothermic circulatory arrest in pigs. Possible mechanisms for this difference are (1) improved oxygen delivery and homogeneity of brain cooling before deep hypothermic circulatory arrest and (2) greater cerebral blood flow and reduced reperfusion injury owing to extracellular acidosis during the rewarming phase. To identify which of these mechanisms is predominant, we studied 49 4-week-old piglets undergoing 1 hour of deep hypothermic circulatory arrest. Four groups were defined according to cooling/rewarming strategy: alpha/alpha, alpha/pH, pH/alpha, and pH/pH. In 24 animals cerebral high-energy phosphate levels and intracellular pH were measured by magnetic resonance spectroscopy (alpha/alpha group 7, alpha/pH group 5, pH/alpha group 7, pH/pH group 5). In 25 animals cerebral blood flow was measured by labeled microspheres, cerebral metabolic rate by oxygen and glucose extraction, and the redox state of cytochrome aa3 and hemoglobin oxygenation by near infrared spectroscopy (alpha/alpha group 7, alpha/pH group 5, pH/alpha group 7, pH/pH group 6). Cerebral blood flow was greater with pH-stat than alpha-stat during cooling (56.3% +/- 3.7% versus 32.9% +/- 2.1% of normothermic baseline values, p < 0.001). Cytochrome aa3 values became more reduced during cooling with alpha-stat than with pH-stat (p = 0.049). Recovery of adenosine triphosphate levels in the initial 45 minutes of reperfusion was more rapid in group pH/pH compared with that in the other groups (p = 0.029). Recovery of cerebral intracellular pH in the initial 30 minutes was faster in group pH/pH compared with that in group alpha/alpha (p = 0.026). Intracellular pH became more acidic during early reperfusion only in group alpha/alpha, whereas it showed continuous recovery in the other groups. This study suggests that there are mechanisms in effect during both the cooling and rewarming phases before and after deep hypothermic circulatory arrest that could contribute to an improved cerebral outcome with pH-stat relative to more alkaline strategies.

Adenosine Triphosphate↗

Effect of sodium nitroprusside on complement activation induced by cardiopulmonary bypass: a clinical and experimental study.

Complement activation and leukocyte stimulation were prospectively studied during and after cardiopulmonary bypass in 16 children receiving sodium nitroprusside--a nitrovasodilator releasing nitric oxide--for vasodilation during the cooling and rewarming periods of extracorporeal circulation. Results were compared with those in 29 patients who were not treated with sodium nitroprusside during the operation. Patients treated with sodium nitroprusside had significantly less C3 conversion during cardiopulmonary bypass as measured by the ratio C3d/C3 (p <0.05) and significantly less C5a liberation immediately after cardiopulmonary bypass (p < 0.005) than patients not treated with sodium nitroprusside. C4 was not overtly consumed in our series. Leukocyte count during the rewarming period of cardiopulmonary bypass, but not leukocyte elastase release during cardiopulmonary bypass, was significantly reduced in patients treated with sodium nitroprusside (p <0.05). In vitro experiments were conducted to analyze the effect of sodium nitroprusside on complement hemolytic activity initiated by the classic and the alternate pathways and on zymosan-induced C3 conversion by the activation of the alternate pathway. The in vitro experiments clearly demonstrate inhibition of complement hemolytic activity by sodium nitroprusside in the sera tested. The 50% inhibitory concentration of sodium nitroprusside on the available complement hemolytic activity was less through the alternate pathway than through the classic one (4.2 +/- 0.8 mmol/L and 14.0 +/- 2.88 mmol/L, respectively). The decrease of complement hemolytic activity measured was dose-dependent and was enhanced by the sodium nitroprusside preincubation of the sera tested. This effect was related to the duration of preincubation. Sodium nitroprusside photodegradation (enhancing nitric oxide release) increased the anticomplementary effect of the drug, reducing the 50% inhibitory concentration on complement hemolytic activity to 0.24 to 0.02 mmol/L for the alternate pathway and 2.74 o 0.3 mmol/L for the classic pathway. the zymosan-induced C3 conversion was inhibited by sodium nitroprusside. Nitroglycerin and isosorbide dinitrate (other nitric oxide donors) had in vitro effects on complement hemolytic activity similar to those of nonphotodegraded sodium nitroprusside at similar concentrations (1 mmol/L). Our results suggest that sodium nitroprusside, both in vitro and in vivo, has an inhibiting effect on complement activation initiated by both classic and alternate pathways and that this effect is mediated by nitric oxide release from sodium nitroprusside. This is the first report on the anticomplementary effect of sodium nitroprusside by nitric oxide release.

Cardiopulmonary Bypass↗

Protein kinase C activation before cardioplegic arrest: beneficial effects on myocyte contractility.

OBJECTIVE: A potential intracellular mechanism for the protective effects of myocardial preconditioning is the activation of protein kinase C. The present study tested the hypothesis that a brief period of protein kinase C activation before cardioplegic arrest would provide protective effects on myocyte contractility with subsequent reperfusion and rewarming. METHODS: Left ventricular porcine myocytes were assigned to the following treatments: (1) Protein kinase C/cardioplegia: Protein kinase C activation in myocytes (n = 39) for 3 minutes with a phorbol ester (10(-9) mol/L of phorbol 12-myristate 13-acetate) in oxygenated, normothermic (37 degrees C) cell media. Protein kinase C activation was followed by 2 hours of cardioplegic arrest (K+, 24 mEq/L; HCO3-, 30 mEq/L; 4 degrees C) and a 5-minute reperfusion period (37 degrees C media). (2) Cardioplegia: Myocytes (n = 31), 2 hours of cardioplegic arrest, and a 5-minute reperfusion and rewarming period. Myocyte contractility was measured by means of high-speed videomicroscopy. For comparison purposes, contractile function was examined in myocytes (n = 70) under normothermic control conditions. RESULTS: Myocyte shortening velocity was reduced after cardioplegic arrest when compared with normothermic values (22.3 +/- 1.6 vs 48.8 +/- 2.0 microm/sec, p < 0.0001). Protein kinase C activation before cardioplegic arrest normalized myocyte shortening velocity (48.8 +/- 2.5 microm/sec). Co-incubation with phorbol 12-myristate 13-acetate and chelerythrine (10(-6) mol/L), an inhibitor of protein kinase C, before cardioplegic arrest abolished the protective effects of phorbol 12-myristate 13-acetate pretreatment. CONCLUSION: These results suggest that an endogenous means of providing improved myocardial protection during prolonged cardioplegic arrest can be achieved through a brief period of protein kinase C activation.

Animals↗

Oxygenation strategy and neurologic damage after deep hypothermic circulatory arrest. I. Gaseous microemboli.

OBJECTIVES: Recent studies suggest that myocardial reperfusion injury is exacerbated by free radicals when pure oxygen is used during cardiopulmonary bypass. Partial replacement of the oxygenator gas mixture with nitrogen, however, such as has already been adopted clinically in many centers, could increase the risk of gaseous nitrogen microembolus formation and therefore of brain damage because of the low solubility of nitrogen, particularly under conditions of hypothermia. METHODS: Ten 7- to 10-kg piglets were cooled for 30 minutes to 15 degrees C on cardiopulmonary bypass and then rewarmed for 40 minutes to 37 degrees C. In 5 piglets cardiopulmonary bypass was normoxic and in 5 it was hyperoxic. In each group 3 bubble oxygenators without arterial filters and 2 membrane oxygenators with filters were used. Cerebral microemboli were monitored continuously by carotid Doppler ultrasonography (8 MHz) and intermittently by fluorescence retinography. RESULTS: Embolus count was greater with lower rectal temperature (P <.001), use of a bubble oxygenator (P <.001), and lower oxygen concentration (P =.021) but was not affected by the temperature gradient between blood and body during cooling or rewarming. CONCLUSIONS: Gaseous microemboli are increased with normoxic perfusion, but this is only important if a bubble oxygenator without a filter is used.

Animals↗

A novel method of induced renal hypothermia.

When the kidney is removed from cold storage for implantation into the recipient it gradually rewarms (second warm ischaemic time) and a prolonged second warm ischaemic time is a risk factor for delayed graft function. A cooling jacket has been designed to prevent this rewarming during transplantation. This study evaluates the efficacy of this device. Surface and core temperatures of less than 15 degrees Centigrade were maintained for 120 minutes. Renal function was significantly better in cooled than in uncooled kidneys in a single kidney canine model. Induced renal hypothermia, using a device such as this, should be a routine manoeuvre in renal transplantation.

Animals↗

Normalization of aortic function during arousal episodes in the hibernating ground squirrel.

Hypothermia is commonly used to restrict organ damage during preservation of tissue, but does not offer complete protection. Organ damage after reperfusion/rewarming is amongst others caused by an impairment of vascular properties, particularly endothelium-dependent vasodilatation. We hypothesized that hibernating small animals, which frequently cycle through periods of deep cooling (torpor) and full rewarming (arousal), employ specific mechanisms to preserve vascular function after cooling and reperfusion. Therefore we measured contraction of aortic tissue of hibernating European ground squirrels after 24 h and 7 days of torpor, arousal (1.5 h) and in non-hibernating animals. To assess the role of nitric oxide (NO), experiments were performed in the absence and presence of the NO-synthesis inhibitor, L-NMMA (10(-4) M). Maximum contraction to phenylephrine and angiotensin II was doubled in 7-days torpid animals without a shift in EC50, compared to the other 3 groups. Maximum contraction to KCl was doubled in 7-days torpid animals compared to the arousal group and non-hibernating animals. Relaxation to acetylcholine (ACh) and sodium nitrite in phenylephrine precontracted rings did not differ between groups. In the presence of L-NMMA, the maximum of concentration-response curves for all three vasoconstrictors was increased by about 30% in the arousal group, but unaffected in other groups. L-NMMA completely inhibited ACh-induced relaxation in 24-h torpid animals and non-hibernating animals, but only partially in 7-days torpid animals and in the arousal group. From this we conclude that vascular adaptation proceeds during torpor. Further, increased contractility of aortic tissue during long torpor returns to normal within 1.5 hours of arousal, which is associated with an increased basal NO synthesis. In addition, involvement of NO in agonist-mediated relaxation differs between the various stages of hibernation.Thus, hibernating animals have effectively developed mechanisms to preserve vascular function after cooling and rewarming.

Animals↗

Comparison of brain tissue metabolic changes during ischemia at 35 degrees and 18 degrees C.

BACKGROUND: We evaluated brain tissue oxygen pressure (PO2), carbon dioxide pressure (PCO2) and pH during ischemia with brain temperature at 35 degrees and 18 degrees C in the same patient. METHODS: Surgery was performed in a 60-year-old woman to clip a large aneurysm in the left internal carotid artery (ICA). A Paratrend 7 probe measuring PO2, PCO2, and pH was inserted into tissue at risk for ischemia during ICA occlusion and brain protection was provided with 9% desflurane. One week later, hypothermic circulatory arrest with brain temperature at 18 degrees C was performed for aneurysm clipping and tissue measurements were obtained during ischemia and rewarming. RESULTS: At 35 degrees C, ICA occlusion for 16 minutes produced tissue hypoxia (PO2 = 0) and acidosis (pH = 6.70). The rate of increase of hydrogen ion (H+) reached 50 nEq.L(-1).min(-1) during ICA occlusion and there was a slow recovery of acidosis at the end of the ischemic period. During hypothermic circulatory arrest, tissue PO2 was sensitive to decreases in blood pressure and decreased rapidly during exsanguination. Although tissue pH decreased to 6.5 with 30 min of no pump flow, the rate of H+ increase during hypothermic arrest was one-third of that seen during ischemia at 35 degrees C. During rewarming from profound hypothermia, two phases of recovery from acidosis were observed, one during CO2 clearance and one after tissue reoxygenation. Recovery of acidosis occurred sooner at 18 degrees C than at 35 degrees C. CONCLUSIONS: These results show that tissue acidosis develops more slowly and recovers more rapidly with hypothermic ischemia. This may be an important mechanism of reduced ischemic injury during hypothermia.

Brain↗

Oesophageal ischaemia in motility disorders associated with chest pain.

The cause of chest pain in diffuse oesophageal spasm and "nutcracker" oesophagus is not clear. Spasm of the oesophageal muscle itself is probably not the cause, because pain and spasm are frequently not coincident. It is suggested instead that oesophageal ischaemia may be the cause of the pain, since the rewarming rate of the oesophagus after a standardised cold challenge was significantly longer in 9 patients with these motility disorders than in 21 normal controls. As rewarming time in other sites correlates with blood flow, these results are consistent with the hypothesis that the oesophagus is ischaemic in these patients.

Adult↗

Moderate hypothermia for uncontrolled intracranial hypertension in acute liver failure.

BACKGROUND: Increased intracranial pressure as a complication of acute liver failure has a mortality of about 90% in patients who do not respond to treatment with mannitol and ultrafiltration. We investigated the safety and efficacy of moderate hypothermia for uncontrolled increase in intracranial pressure in patients with acute liver failure. METHODS: We studied seven consecutive patients aged 16-46 years (five women, four candidates for orthotopic liver transplantation [OLT]) with acute liver failure who fulfilled criteria for poor-prognosis liver failure and had increased intracranial pressure that was unresponsive to two treatments with mannitol and ultrafiltration. We used cooling blankets to lower the patients' core temperature to 32-33 degrees C. Patients who were not suitable candidates for OLT (patients 1-3) were cooled for 8 h and then gradually rewarmed over 1 h to a baseline temperature of 37 degrees C. Patients who were suitable candidates for OLT (patients 4-7) were cooled before and during the OLT procedure. We measured cerebral blood flow and metabolic indices before and after cooling. FINDINGS: The four patients who were candidates for OLT were successfully maintained until transplantation with 13 (range 10-14) h of hypothermia. The three patients who were unsuitable candidates for OLT died after rewarming. Intracranial pressure before cooling was 45 (25-49) mm Hg and was reduced in all patients to 16 (13-17) mm Hg (p<0.05). Cerebral blood flow decreased from 103 (25-134) mL 100 g(-1) min(-1) before cooling to 44 (24-75) mL 100 g(-1) min(-1) after cooling (p<0.05). The corresponding changes for cerebral perfusion pressure was an increase from 45 (37-56) mm Hg to 70 (60-78) mm Hg (p<0.05) and for cardiac index a decrease from 9.8 (7-13) to 5.1 (4.3-6.1) L per min per m2 of body surface area. During hypothermia there was no significant relapse of increased intracranial pressure. Arterial ammonia and cerebral uptake of ammonia were significantly reduced with cooling. No adverse effects of hypothermia were observed. INTERPRETATION: Moderate hypothermia is useful in the treatment of uncontrolled increase in intracranial pressure in patients with acute liver failure and may serve as a bridge to OLT.

Acute Disease↗

Hypothermia.

Significant hypothermia is an increasing clinical problem that requires a rapid response with properly trained personnel and techniques. Although the clinical presentation may be such that the victim appears dead, aggressive management may allow successful resuscitation in many instances. Initial management should include CPR if the victim is not breathing or is pulseless. Further core heat loss should be prevented by removing wet garments, insulating the victim, and ventilating with warm humidified air/oxygen to help stabilize core temperature. Core temperature and cardiac rhythm should be monitored in the prehospital setting, if possible, and CPR should be continued during transport. In-hospital management should consist of rapid core rewarming in the severely hypothermic victim with heated humidified oxygen, centrally administered warm IV fluids (43 C), and peritoneal dialysis until extracorporeal rewarming can be accomplished. Postresuscitation complications should be monitored; they include pneumonia, pulmonary edema, cardiac arrhythmias, myoglobinuria, disseminated intravascular thrombosis, and seizures. The decision to terminate resuscitative efforts must be individualized by the physician in charge.

Body Temperature↗

Closed thoracic cavity lavage in the treatment of severe hypothermia in human beings.

Life-threatening hypothermia can be treated by active and passive rewarming techniques, the treatment of choice being partial cardiopulmonary bypass. The use of closed thoracic cavity lavage has been evaluated in animals, but no formal presentations in human beings have been reported. We report two cases in which rapid rewarming in severe hypothermia was accomplished when cardiopulmonary bypass was not available.

Adult↗

Severe exposure hypothermia: a resuscitation protocol.

Although hypothermia has been described as an emergency in suspended animation, severe degrees of hypothermia mandate appropriate aggressive intervention. Because of cardiac instability with core temperature below 28 C, aggressive invasive rewarming by F-F partial bypass is often ideal in this setting. In contrast, a gentle approach in other therapeutic maneuvers is equally important to prevent iatrogenic induction of VF in nonarrested victims. If the only definite criterion for diagnosis of death in hypothermia is failure to respond to resuscitation and rewarming, successful resuscitation must carefully balance aggressive and gentle interventions. Because CPR protocols involve legal as well as medical questions, additional prospective data are especially critical for resolving controversies in the initial management of profound exposure hypothermia.

Arrhythmias, Cardiac↗

Successful resuscitation of a severely hypothermic neonate.

A profoundly hypothermic 5-hour-old infant in cardiac arrest was brought to the emergency department by paramedics. The infant was found wrapped in a garbage bag inside a freezer. She had been in the freezer for approximately four hours. Her initial rectal temperature was 16.2 degrees C. Active external and core warming modalities, including warm blanket, radiant heat lamp, warm humidified air, heated gastric lavage, and heated bladder lavage, were used to rewarm the infant. Her temperature rose to 30.5 degrees C in three hours (4.8 degrees C/hr). The infant converted from a slow idioventricular rhythm to sinus bradycardia at 49 minutes (20.4 degrees C) into the resuscitation. At 53 minutes (21.5 degrees C), the infant moved both upper extremities. At the time of discharge from the hospital, she had no significant physical or neurologic problems. Neurologic examination at 4 months was normal. This report supports prior recommendations to aggressively rewarm severely hypothermic infants in cardiac arrest.

Cardiopulmonary Resuscitation↗