Temperature Variation After Rewarming from Deep Hypothermic Circulatory Arrest Is Associated with Survival and Neurologic Outcome.

Therapeutic hypothermia is recommended by international guidelines after cardio-circulatory arrest. However, the effects of different temperatures during the first 24 hours after deep hypothermic circulatory arrest (DHCA) for aortic arch surgery on survival and neurologic outcome are undefined. We hypothesize that temperature variation after aortic arch surgery is associated with survival and neurologic outcome. In the period 2010-2014, a total of 210 consecutive patients undergoing aortic arch surgery with DHCA were included. They were retrospectively divided into three groups by median nasopharyngeal temperature within 24 hours after rewarming: hypothermia (<36°C; n = 65), normothermia (36-37°C; n = 110), and hyperthermia (>37°C; n = 35). Multivariate stepwise logistic and linear regressions were performed to determine whether different temperature independently predicted 30-day mortality, stroke incidence, and neurologic outcome assessed by cerebral performance category (CPC) at hospital discharge. Compared with normothermia, hyperthermia was independently associated with a higher risk of 30-day mortality (28.6% vs. 10.9%; odds ratio [OR] 2.8; 95% confidence interval [CI], 1.1-8.6; p = 0.005), stroke incidence (64.3% vs. 9.1%; OR 9.1; 95% CI, 2.7-23.0; p = 0.001), and poor neurologic outcome (CPC 3-5) (68.8% vs. 39.6%; OR 4.8; 95% CI, 1.4-8.7; p = 0.01). No significant differences were demonstrated between hypothermia and normothermia. Postoperative hypothermia is not associated with a better outcome after aortic arch surgery with DHCA. However, postoperative hyperthermia (>37°C) is associated with high stroke incidence, poor neurologic outcome, and increased 30-day mortality. Target temperature management in the first 24 hours after surgery should be evaluated in prospective randomized trials.

Morbidity and mortality associated with rewarming hypothermic very low birth weight infants.

OBJECTIVES: In very low birthweight (VLBW) infants, hypothermia is associated with poor outcomes. The goal of this study is to assess the relationship between the rate of rewarming these babies and their outcomes. METHODS: This is a retrospective cohort study of 98 inborn VLBW infants who were hypothermic (<36°C rectally) upon admission to the NICU. A logistic regression model was used to examine the relationship between the rates of rewarming and time to achieve euthermia and the following outcomes: death, intraventricular hemorrhage, severe intraventricular hemorrhage, bronchopulmonary dysplasia, necrotizing enterocolitis and retinopathy of prematurity. RESULTS: Prolonged rewarming time was associate with increased odds of mortality (OR 1.273 95% CI 1.032-1.571). No associations between rewarming rates and any of the outcomes were seen. Once birthweight was included in a multiple logistic regression model, the association between mortality and rewarming time was no longer significant. Outcomes that were not associated with either rate or time of rewarming (even in a univariate model) were: bronchopulmonary dysplasia, intraventricular hemorrhage, severe intraventricular hemorrhage, necrotizing enterocolitis and retinopathy of prematurity. CONCLUSION: In moderately hypothermic VLBW infants, after accounting for birthweight, no association between rewarming and outcome is seen.

Intracranial Pressure Increases During Rewarming Period After Mild Therapeutic Hypothermia in Postcardiac Arrest Patients.

Elevation of intracranial pressure (ICP) may worsen brain injury and neurological outcome. Studies on the use of therapeutic hypothermia (TH) for traumatic brain injury suggests that rapid rewarming from TH is associated with elevated ICP and poorer outcomes. However, few studies describe the time course of ICP changes during TH/rewarming after cardiac arrest (CA). In this study, we observed the changes in ICP during mild TH and rewarming after CA. Secondarily, we examined whether ICP is related to outcome. We studied comatose patients resuscitated from CA, who were treated with TH and who had ICP monitored. Target core temperature was 34°C for 24 h and target rewarming rate was 0.25°C/h. ICP and cerebral perfusion pressure (CPP) were monitored during the period. Outcome was rated as cerebral performance category. In nine patients, ICP increased during TH and rewarming (6.0 [4.0-9.0] mmHg to 16.0 [12.0-26.0] mmHg, p = 0.008). CPP did not change during the period (83.3 [80.1-91.0] mmHg to 74.3 [52.0-87.3] mmHg). Higher ICP was associated with worse outcomes (p = 0.009). All the cases with ICP >25 mmHg or CPP <40 mmHg died. Major ICP increment was observed during the rewarming period, although, some increase of ICP occurred even during the mild TH. ICP increment was higher in patients with worse outcomes.

Controlled Oxygenated Rewarming of Cold Stored Livers Prior to Transplantation: First Clinical Application of a New Concept.

BACKGROUND: Abrupt temperature shift from hypothermia to normothermia incurred on reperfusion of organ grafts has been delineated as a genuine factor contributing to reperfusion injury and graft dysfunction after transplantation. METHODS: In a first clinical series of 6 patients, cold-stored livers, all allocated by the rescue offer mechanism by Eurotransplant, were subjected to machine-assisted slow controlled oxygenated rewarming (COR) for 90 minutes before engrafting. A historical cohort of 106 patients basically similar in graft (all rescue offer organs) and recipient factors was used for comparison. RESULTS: The clinical benefit of COR was documented by a significant reduction by approximately 50% in peak serum transaminases after transplantation compared to untreated controls (AST 563.5 vs. 1204 U/L, P = 0.023). After 6 months graft survival was 100% in the COR group and 80.9% in the controls (P = 0.24). Respective patient survival was 100% and 84.7% (P = 0.28). Real-time assessment of glucose concentration in the perfusion solution correlated well with postoperative synthetic graft function (r = 0.78; P < 0.02). All treated recipients had normal liver function after a 6-month follow-up and are well and alive. CONCLUSIONS: This first clinical application suggests that controlled graft rewarming after cold storage is a feasible and safe method in clinical praxis and might become an adjunct in organ preservation.

High resolution ECG-aided early prognostic model for comatose survivors of out of hospital cardiac arrest.

Out of hospital cardiac arrest (OHCA) has a high mortality despite modern treatment. Reliable early prognosis in OHCA could significantly improve clinical decision making. We explored prognostic utility of advanced ECG parameters, obtained from high-resolution ECG, in combination with clinical and OHCA-related parameters during treatment with mild induced hypothermia (MIH) and after rewarming in unconscious survivors of OHCA. Ninety-two patients during MIH and 66 after rewarming were included. During MIH, a score based on initial rhythm, QRS-upslope and systolic pressure resulted in an area under curve (AUC) of 0.82 and accuracy of 80% for survival. After rewarming, a score based on admission rhythm, sum of 12 lead QRS voltages, and mean lateral ST segment level in leads I and V6 resulted in an AUC of 0.88 and accuracy of 85% for survival. ECG can assist with early prognostication in unconscious survivors of OHCA during MIH and after rewarming.

Pediatric submersion injuries: emergency care and resuscitation.

Drowning and submersion injuries are highly prevalent, yet preventable, causes of childhood mortality and morbidity. Although much of the resuscitation of the drowning pediatric victim is basic to all respiratory and cardiac arrest situations, there are some caveats for treatment of this type of injury. Risk factors for drowning victims include epilepsy, underlying cardiac dysrhythmias, hyperventilation, hypoglycemia, hypothermia, and alcohol and illicit drug use. Prehospital care should focus on restoring normal ventilation and circulation as quickly as possible to limit the extent of hypoxic insult. Diagnostic testing for symptomatic patients may include blood glucose level, arterial blood gas level, complete blood count, electrolytes levels, chest radiography, and cardiorespiratory monitoring with pulse oximetry and a rhythm strip. In this review, passive external, active external, and active internal rewarming techniques for treatment of hypothermic patients are discussed. A systematic approach to treatment and disposition or admission of pediatric drowning victims is also included, with extensive clinical pathways for quick reference.

Improved outcomes of transported neonates in Beijing: the impact of strategic changes in perinatal and regional neonatal transport network services.

BACKGROUND: Infants born outside perinatal centers may have compromised outcomes due to the transfer speed and efficiency to an appropriate tertiary center. This study aimed to evaluate the impact of regional coordinated changes in perinatal supports and retrieval services on the outcome of transported neonates in Beijing, China. METHODS: Information about transported newborns between phase 1 (July 1, 2004 to June 30, 2006) and phase 2 (July 1, 2007 to June 30, 2009) was collected. The strategic changes during phase 2 included standardized neonatal transport procedures, skilled attendants, a perinatal consulting service, and preferential admission of transported neonates to the intensive care unit of the tertiary care center. Data from phase 2 (after-strategic changes) were compared with those of phase 1 (the period of pre-strategic changes) after a 12-month washout period, especially regarding the reduction in mortality and selected morbidity. RESULTS: There was a large increase in the number of transported infants in phase 2 compared with phase 1 (2797 vs. 567 patients). The average monthly rate of increase of transported infants was 383.3% (from 24 infants per month to 116 infants per month). The mortality rate of transported neonates reduced significantly from phase 1 to phase 2 (5.11% vs. 2.82%; P=0.005), particularly for preterm infants (8.47% vs. 4.34%; P=0.006). In addition, transported neonates during phase 2 had significantly decreased morbidities. CONCLUSIONS: Regional coordinated strategies optimizing the perinatal services and transport of outborn sick and preterm infants to tertiary care centers improved survival outcomes considerably. These findings have vital implications for health outcomes and resource planning.

Fever after rewarming: incidence of pyrexia in postcardiac arrest patients who have undergone mild therapeutic hypothermia.

BACKGROUND: Induction of mild therapeutic hypothermia (TH; temperature 32-34°C) has become standard of care in many hospitals for comatose survivors of cardiac arrest. Pyrexia, or fever, is known to be detrimental in patients with neurologic injuries such as stroke or trauma. The incidence of pyrexia in the postrewarming phase of TH is unknown. We attempted to determine the incidence of fever after TH and hypothesized that those patients who were febrile after rewarming would have worse clinical outcomes than those who maintained normothermia in the postrewarming period. METHODS: Retrospective data analysis of survivors of out-of-hospital cardiac arrest (OHCA) over a period of 29 months (December 2007 to April 2010). INCLUSION CRITERIA: OHCA, age >18, return of spontaneous circulation, and treatment with TH. EXCLUSION CRITERIA: traumatic arrest and pregnancy. Data collected included age, sex, neurologic outcome, mortality, and whether the patient developed fever (temperature > 100.4°F, 38°C) within 24 hours after being fully rewarmed to a normal core body temperature after TH. We used simple descriptive statistics and Fisher exact test to report our findings. RESULTS: A total of 149 patients were identified; of these, 82 (55%) underwent TH. The mean age of the TH cohort was 66 years, and 28 (31%) were female. In all, 54 patients survived for >24 hours after rewarming and were included in the analysis. Among the analyzed cohort, 28 (52%) of 54 developed fever within 24 hours after being rewarmed. Outcome measures included in-hospital mortality as well as neurologic outcome as defined by a dichotomized Cerebral Performance Category (CPC) score. When comparing neurologic outcomes between the groups, 16 (57%) of 28 in the postrewarming fever group had a poor outcome (CPC score 3-5), while 15 (58%) of 26 in the no-fever group had a favorable outcome (P = .62). In the fever group, 15 (52%) of 28 died, while in the no-fever group, 14 (54%) of 26 died (P = .62). CONCLUSION: Among a cohort of patients who underwent mild TH after OHCA, more than half of these patients developed pyrexia in the first 24 hours after rewarming. Although there were no significant differences in outcomes between febrile and nonfebrile patients identified in this study, these findings should be further evaluated in a larger cohort. Future investigations may be needed to determine whether postrewarming temperature management will improve the outcomes in this population.

Veno-venous perfusion to cool and rewarm in thoracic and thoracoabdominal aortic aneurysm repair.

BACKGROUND: Femoro-femoral veno-arterial perfusion is an established circulatory support and cooling method for thoracic- and/or thoracoabdominal aortic aneurysm repair. However, retrograde perfusion through femoral arteries can lead to retrograde cerebral embolization and neurologic dysfunction after surgery. To avoid these complications, we have established a femoro-femoral veno-venous perfusion technique and evaluated its safety and effectiveness in elective and nonelective patients. METHODS: Common femoral veins were cannulated bilaterally percutaneously following systemic low-dose heparinization (100 IU/kg body weight). Venous blood was drained from drainage of the inferior vena cava, and venous return followed through the superior vena cava. After proximal aortic cross-clamping, veno-venous perfusion was switched to veno-arterial antegrade perfusion through the distal descending thoracic aorta to achieve spinal and visceral perfusion or through iliac arteries for distal perfusion combined with selective renovisceral blood perfusion. After completion of aortic repair, the arterial cannula was removed and the patient rewarmed just by switching back to veno-venous perfusion. Gas and temperature exchange as well as relevant hemodynamic parameters were recorded prospectively and analyzed retrospectively in 25 consecutive patients including 15 nonelective cases. RESULTS: Percutaneous insertion of outflow (28F cannula) and inflow (18F cannula) venous cannulae was complication-free and allowed unrestricted perfusion in all 25 patients. Veno-venous perfusion allowed effective cooling (mean body temperature 36.6 ± 0.6°C to 31.6 ± 2.1°C, P = .001 compared with start of cooling) and re-warming (mean body temperature 30.5 ± 3°C to 36.3 ± 0.8°C, P = .03 compared with start of re-warming). Hemodynamic as well as pulmonary parameters remained remarkably stable during surgical dissection and single lung ventilation even in nonelective cases. There was no complication associated with the perfusion technique during surgery. CONCLUSIONS: Transfemoral veno-venous cooling and re-warming results in remarkable hemodynamic stability during open repair of thoracic- and/or thoracoabdominal aortic aneurysms and eliminates the need for retrograde arterial perfusion and its inherent risks.

When should cardiopulmonary bypass be used in the setting of severe hypothermic cardiac arrest?

A best evidence topic was written according to a structured protocol. The question addressed was regarding the indication and timing of the use of cardiopulmonary bypass (CPB), following severe hypothermic cardiac arrest. A total of 284 papers were found using the reported searches, of which nine represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. Reported measures were survival, rewarming speed, incidence of arrhythmia during rewarming, resolution of full neurological function, long-term neurological function, evidence of damage on neurological imaging and venous metabolic parameters in hypothermic patients. The most recent of the best evidence studies, a retrospective comparative study of 68 patients, demonstrated CPB rewarming to be far superior to conventional methods of rewarming, with mortality rates of 15.8 and 53.3%, respectively. Another study of similar size, comparing CPB with extracorporeal membrane oxygenation (ECMO) for rewarming, revealed superior survival rates with ECMO, 75 vs 34%. A systematic review of 68 patients demonstrated an overall survival of 60%, and 80% of survivors returning to a previous level of activity. Two smaller observational studies reported survival rates of 73.1 and 45.5%, respectively. A retrospective study analysing long-term neurological outcomes of survivors reported normal history and physical examination in 93.3%, normal neurovascular ultrasound in 100%, normal neuropsychological findings in 93.3% and normal brain magnetic resonance imaging in 86.7%. A small comparative study demonstrated a significant survival benefit when CPB was preceded with emergency thoracotomy, internal cardiac massage and warm mediastinal irrigation compared with CPB alone. We conclude that, following deep hypothermic circulatory arrest, the urgent use of cardiopulmonary bypass is widely indicated for rewarming where it has been shown to provide good survival and neurological outcomes far superior in comparison with conventional methods of rewarming.

Treatment of term infants with head cooling and mild systemic hypothermia (35.0 degrees C and 34.5 degrees C) after perinatal asphyxia.

OBJECTIVE: To assess the safety of selective head cooling in birth-asphyxiated term newborn infants while maintaining the rectal temperature at 35.0 degrees C or 34.5 degrees C. METHODS: Twenty-six term infants with Apgar