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- Interventions for treating inadvertent postoperative hypothermia. [JOURNAL ARTICLE]
- Cochrane Database Syst Rev 2014 Nov 20.:CD009892.
Inadvertent postoperative hypothermia (a drop in core body temperature to below 36°C) occurs as an effect of surgery when anaesthetic drugs and exposure of the skin for long periods of time during surgery result in interference with normal temperature regulation. Once hypothermia has occurred, it is important that patients are rewarmed promptly to minimise potential complications. Several different interventions are available for rewarming patients.To estimate the effectiveness of treating inadvertent perioperative hypothermia through postoperative interventions to decrease heat loss and apply passive and active warming systems in adult patients who have undergone surgery.We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2014, Issue 2), MEDLINE (Ovid SP) (1956 to 21 February 2014), EMBASE (Ovid SP) (1982 to 21 February 2014), the Institute for Scientific Information (ISI) Web of Science (1950 to 21 February 2014) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL), EBSCO host (1980 to 21 February 2014), as well as reference lists of articles. We also searched www.controlled-trials.com and www.clincialtrials.gov.Randomized controlled trials of postoperative warming interventions aiming to reverse hypothermia compared with control or with each other.Three review authors identified studies for inclusion in this review. One review author extracted data and completed risk of bias assessments; two review authors checked the details. Meta-analysis was conducted when appropriate by using standard methodological procedures as expected by The Cochrane Collaboration.We included 11 trials with 699 participants. Ten trials provided data for analysis. Trials varied in the numbers and types of participants included and in the types of surgery performed. Most trials were at high or unclear risk of bias because of inappropriate or unclear randomization procedures, and because blinding of assessors and participants generally was not possible. This may have influenced results, but it is unclear how the results may have been influenced. Active warming was found to reduce the mean time taken to achieve normothermia by about 30 minutes in comparison with use of warmed cotton blankets (mean difference (MD) -32.13 minutes, 95% confidence interval (CI) -42.55 to -21.71; moderate-quality evidence), but no significant difference in shivering was noted. Active warming was found to reduce mean time taken to achieve normothermia by almost an hour and a half in comparison with use of unwarmed cotton blankets (MD -88.86 minutes, 95% CI -123.49 to -54.23; moderate-quality evidence), and people in the active warming group were less likely to shiver than those in the unwarmed cotton blanket group (Relative Risk=0.61 95% CI= 0.42 to 0.86; low quality evidence). There was no effect on mean temperature difference in degrees celsius at 60 minutes (MD=0.18°C, 95% CI=-0.10 to 0.46; moderate quality evidence), and no data were available in relation to major cardiovascular complications. Forced air warming was found to reduce time taken to achieve normothermia by about one hour in comparison to circulating hot water devices (MD=-54.21 minutes 95% CI= -94.95, -13.47). There was no statistically significant difference between thermal insulation and cotton blankets on mean time to achieve normothermia (MD =-0.29 minutes, 95% CI=-25.47 to 24.89; moderate quality evidence) or shivering (Relative Risk=1.36 95% CI= 0.69 to 2.67; moderate quality evidence), and no data were available for mean temperature difference or major cardiovascular complications. Insufficient evidence was available about other comparisons, adverse effects or any other secondary outcomes.Active warming, particularly forced air warming, appears to offer a clinically important reduction in mean time taken to achieve normothermia (normal body temperature between 36°C and 37.5°C) in patients with postoperative hypothermia. However, high-quality evidence on other important clinical outcomes is lacking; therefore it is unclear whether active warming offers other benefits and harms. High-quality evidence on other warming methods is also lacking; therefore it is unclear whether other rewarming methods are effective in reversing postoperative hypothermia.
- Passive rewarming from torpor in hibernating bats: minimizing metabolic costs and cardiac demands. [JOURNAL ARTICLE]
- Am J Physiol Regul Integr Comp Physiol 2014 Nov 19.:ajpregu.00341.2014.
Endothermic arousal from torpor is an energetically costly process and imposes enormous demands on the cardiovascular system, particularly during early stage arousal from low body temperature (Tb). To minimize these costs many bats and other heterothermic endotherms rewarm passively from torpor using solar radiation or fluctuating ambient temperature (Ta). Because the heart plays a critical role in the arousal process in terms of blood distribution and as a source of heat production it is desirable to understand how the function of this organ responds to passive rewarming and how this relates to changes in metabolism and Tb. We investigated heart rate (HR) in hibernating long-eared bats (Nyctophilus gouldi) and its relationship to oxygen consumption (V̇O2) and subcutaneous temperature (Tsub) during exposure to increasing Ta in comparison to endogenous arousals at constant low Ta. During passive rewarming, HR and V̇O2 remained low over a large Tsub range and increased concurrently with increasing Ta (Q10 2.4 and 2.5, respectively). Absolute values were higher than during steady-state torpor, but below those measured during torpor entry. During active arousals, mean HR and V̇O2 were substantially higher than during passive rewarming at corresponding Tsub. In addition, partial passive rewarming reduced the cost of arousal from torpor by 53% compared to entirely active arousal. Our data show that passive rewarming considerably reduces arousal costs and arousal time; we suggest this may also contribute to minimizing exposure to oxidative stresses as well as demands on the cardiovascular system.
- [The use of intravascular hypothermia to correct intracranial hypertension in patients with severe traumatic brain injury.] [JOURNAL ARTICLE]
- Zh Vopr Neirokhir Im N N Burdenko 2014; 78(5):41-48.
Objective: Assess to impact hypothermia on ABP, CPP, ICP and cerebral autoregulation. Material and methods. 14 patients with TBI (GOS<9) underwent hypothermia by Thermogard system within 32-35 °C (Zoll, USA). ICP was measured intraparenchymal by Codman sensor. Cerebral autoregulation was estimated by correlation coefficient Prx (Soft ICM Plus, Cambridge, UK). Temperature was measured in urinary bladder. There were selected five time periods: 1 - phase of initial state, 2 - phase of induction hypothermia, 3 - phase of hypothermia, 4 - phase of rewarming, 5 - phase after finishing hypothermia. All data preset as Mediana (min; max). Stat analysis was perfomed using Soft Statistica 10.0. Results. Phase 1 lasted nearly 7 (2; 12) h, ABP 94 (81; 102), CPP - 73 (52; 87), ICP 27 (16; 45) mm Hg, Prx 0,25 (-0,15; 0,7), temperature 38,2 °C (37; 39,8). Phase 2: 5 (2; 12) h, ABP 95 (85; 114), CPP 80 (65; 96), ICP 18 (10; 22) mm Hg, Prx -0,055 (-0,15; 0,7), temperature 35,2 °C (34,5; 35,5). Phase 3: 55 (20; 100) h, there were not significant changed ABP, CPP, Prx, ICP 15 (10; 18) mm Hg, temperature was 33,5 °C (32; 34,7). Phase 4: 17 (8; 24) h, ABP 90 (70; 100), CPP 77 (55; 85), ICP 15 (9; 27) mm Hg and Prx 0,2 (-0,2; 0,32). Temperature 36,9 °C (35,9; 38,5). Phase 5: 20 (6; 240) h, ABP 87(53; 110), CPP 72 (47; 107), ICP 17 (10; 32) mm Hg and Prx 0,2 (-0,2; 0,6). Temperature 37,7 °C (36,7; 39,0). Conclusion. Hypothermia is an effective method for correction of intracranial hypertension. Hypothermia can use as a additional option of intensive care during refractory intracranial hypertension. Rewarming phase is the most dangerous time on the re-development of intracranial hypertension and disruption of autoregulation.
- Out in the cold: the hypothermic heart response. [JOURNAL ARTICLE]
- BMJ Case Rep 2014.
We present an interesting case of a 49-year-old woman with hypothermia and associated Osborn waves (also called J waves) on ECG. She was found on the floor of her home and difficult to arouse. On arrival to the emergency department (ED), her rectal temperature was 87.5°F. ECG showed Osborn waves in diffuse leads. She was intubated in the ED and was started on vasopressor support for hypotension refractory to intravenous fluid boluses. She was transferred to the critical care unit for continued respiratory and cardiovascular support. With active external rewarming her core body temperature continued to improve. Blood pressure also improved and vasopressor was tapered off. She was extubated and was transferred to the medical floor for continued supportive care. Osborn waves on ECG resolved within 12 h of achieving normal range body temperature. The patient was eventually discharged home with medical follow-up.
- A cardiopulmonary bypass with deep hypothermic circulatory arrest rat model for the investigation of the systemic inflammation response and induced organ damage. [Journal Article]
- J Inflamm (Lond) 2014.:26.
Cardiopulmonary bypass (CPB) is a commonly used technique in cardiac surgery. CPB is however associated with a strong induction of systemic inflammatory response syndrome (SIRS) which in conjunction with ischemia and reperfusion may lead to multiple organ failure. The aim of the study was to establish and characterize a CPB rat model incorporating deep hypothermic circulatory arrest with a specific focus on the extent of the inflammatory reactions and organ damage as a groundwork for novel therapeutics against SIRS and I/R induced organ injury.Male Wistar rats (n = 6) were cannulated for CPB, connected to a heart-lung-machine (HLM) and cooled to a temperature of 16°C before they underwent 45 minutes of deep hypothermic circulatory arrest with global ischaemia. Arrest was followed by rewarming and 60 minutes of reperfusion. Haemodynamic and vital parameters were recorded throughout the CPB procedure. Only animals displaying sinus rhythm throughout reperfusion were utilized for analysis. Rats were euthanized and tissue samples were harvested. Blood gas analysis was performed and blood samples were taken. Induction of organ damage was examined by analysis of protein levels and phosphorylation status of kinases and stress proteins. Results were compared to animals (n = 6) which did not undergo CPB.CPB induced leucocytosis and an increase of interleukin-6 and TNF-α plasma values indicating an inflammatory response. Markers of tissue damage and dysfunction, such as troponin T, creatinine and AST were elevated. Phosphorylation of STAT3 was induced in all examined organs. Activation of MAPK and induction of heat shock proteins occurred in an organ-specific manner with most pronounced effects in heart, lungs and kidneys.The presented CPB rat model shows the induction of SIRS and activation of specific signalling cascades. SIRS seems not to be provoked during DHCA and is elicited mainly during reperfusion. This model might be suitable to test the efficacy of therapeutics applied in major heart surgery with and without DHCA.
- Prognostication in comatose survivors of cardiac arrest: An advisory statement from the European Resuscitation Council and the European Society of Intensive Care Medicine. [JOURNAL ARTICLE]
- Intensive Care Med 2014 Nov 15.
To review and update the evidence on predictors of poor outcome (death, persistent vegetative state or severe neurological disability) in adult comatose survivors of cardiac arrest, either treated or not treated with controlled temperature, to identify knowledge gaps and to suggest a reliable prognostication strategy.GRADE-based systematic review followed by expert consensus achieved using Web-based Delphi methodology, conference calls and face-to-face meetings. Predictors based on clinical examination, electrophysiology, biomarkers and imaging were included.Evidence from a total of 73 studies was reviewed. The quality of evidence was low or very low for almost all studies. In patients who are comatose with absent or extensor motor response at ≥72 h from arrest, either treated or not treated with controlled temperature, bilateral absence of either pupillary and corneal reflexes or N20 wave of short-latency somatosensory evoked potentials were identified as the most robust predictors. Early status myoclonus, elevated values of neuron-specific enolase at 48-72 h from arrest, unreactive malignant EEG patterns after rewarming, and presence of diffuse signs of postanoxic injury on either computed tomography or magnetic resonance imaging were identified as useful but less robust predictors. Prolonged observation and repeated assessments should be considered when results of initial assessment are inconclusive. Although no specific combination of predictors is sufficiently supported by available evidence, a multimodal prognostication approach is recommended in all patients.
- Development of an encapsulation-vitrification protocol for Rubia akane (nakai) hairy roots: a comparison with non-encapsulation. [Journal Article]
- Cryo Letters 2014 Sep-Oct; 35(5):377-84.
A comparison of different cryopreservation techniques should be based on the characteristics of both the methodology and the material in question using an optimized procedure.This study aimed at developing an encapsulation-vitrification procedure for hairy roots of Rubia akane using alternative loading and vitrification solutions, based on the existing optimized droplet-vitrification procedure.Encapsulated roots were first precultured in liquid medium with 10% sucrose for 3 days, then with 17.5 % sucrose for 1 day, after which they were osmoprotected with solution C6-40 % (20 % glycerol + 20 % sucrose) for 50 min, cryoprotected with solution A3-90 % (37.5 % glycerol + 15 % DMSO + 15 % EG + 22.5 % sucrose, w/v) on ice for 40 min, cooled and warmed in 2 ml cryovials, and unloaded in 35% sucrose solution for 60 min.Through the application of this procedure to aged-clustered roots, up to 97.5 % post-cryopreservation regeneration was observed. In our previous study, droplet-vitrification of hairy roots of R. akane resulted in 83.8 % post-rewarming regeneration following preculture with 10 % sucrose for 2 days and 17.5 % sucrose for 4-5 h, and osmoprotection with solution C4-35 % (17.5 % glycerol + 17.5 % sucrose) for 30 min, and cryoprotection with solution A3-70 % (29.2 % glycerol + 11.7 % DMSO + 11.7% EG + 17.4% sucrose, w/v) on ice for 20 min. In the present study, higher post-cryopreservation regeneration was observed by using a higher concentration of vitrification solution (A3-70 % → A3-90 %, B5-80 % → B1-100 %) and/or a longer cryoprotection duration (A3-70 % at room temperature (RT) for 8 min → 15-30 min, on ice for 20 min → 40-80 min; B5-80 % for 15 min → 30-60 min).Even though encapsulation provided some degree of protection from the cytotoxicity of vitrification solutions to cytotoxicity-sensitive R. akane hairy roots, an overall higher post-cryopreservation regrowth was obtained using the droplet-vitrification procedure under optimized conditions. This result implies that this sensitive material was not sufficiently cryoprotected, and thus, rapid cooling and warming using foil strips was more efficient than cryopreservation of encapsulated samples.
- Comparison of two fluid warming devices for maintaining body core temperature during living donor liver transplantation: Level 1 H-1000 vs. Fluid Management System 2000. [Journal Article]
- Korean J Anesthesiol 2014 Oct; 67(4):264-9.
Rapid fluid warming has been a cardinal measure to maintain normothermia during fluid resuscitation of hypovolemic patients. A previous laboratory simulation study with different fluid infusion rates showed that a fluid warmer using magnetic induction is superior to a warmer using countercurrent heat exchange. We tested whether the simulation-based result is translated into the clinical liver transplantation.Two hundred twenty recipients who underwent living donor liver transplantation between April 2009 and October 2011 were initially screened. Seventeen recipients given a magnetic induction warmer (FMS2000) were matched 1 : 1 with those given a countercurrent heat exchange warmer (Level-1 H-1000) based on propensity score. Matched variables included age, gender, body mass index, model for end-stage liver disease score, graft size and time under anesthesia. Core temperatures were taken at predetermined time points.Level-1 and FMS groups had comparable core temperature throughout the surgery from skin incision, the beginning/end of the anhepatic phase to skin closure. (P = 0.165, repeated measures ANOVA). The degree of core temperature changes within the dissection, anhepatic and postreperfusion phase were also comparable between the two groups. The minimum intraoperative core temperature was also comparable (Level 1, 35.6℃ vs. FMS, 35.4℃, P = 0.122).A countercurrent heat exchange warmer and magnetic induction warmer displayed comparable function regarding the maintenance of core temperature and prevention of hypothermia during living donor liver transplantation. The applicability of the two devices in liver transplantation needs to be evaluated in various populations and clinical settings.
- Recent advances and future directions of hypothermia therapy for traumatic brain injury. [Journal Article]
- Neurol Med Chir (Tokyo) 2014 Nov 15; 54(11):863-9.
For severe traumatic brain injury (TBI) patients, no effective treatment method replacing hypothermia therapy has emerged, and hypothermia therapy still plays the major role. To increase its efficacy, first, early introduction is important. Since there are diverse pathologies of severe TBI, it is necessary to appropriately control the temperature in the hypothermia maintenance and rewarming phases by monitoring relative to the pathology. Currently, hypothermia is considered appropriate for severe TBI patients requiring craniotomy for removal of hematoma, while induced normothermia is appropriate for severe TBI patients with diffuse brain injury. Induced normothermia is expected to exhibit a cerebroprotective effect equivalent to hypothermia, as well as reduce the complexity of whole-body management and systemic complications. According to the Japan Neurotrauma Data Bank of the Japan Society of Neurotraumatology, the brain temperature was controlled in 43.9% of severe TBI patients (induced normothermia: 32.2%, hypothermia: 11.7%) in Japan. Brain temperature management was performed mainly in young patients, and the outcome on discharge was favorable in patients who received brain temperature management. Particularly, patients who need craniotomy for removal of hematoma were a good indication of therapeutic hypothermia. Improvement of therapeutic outcomes with widespread temperature management in TBI patients is expected.
- [Prognostic assessment as the basis for limiting therapy in unconscious patients after cardiopulmonary resuscitation.] [JOURNAL ARTICLE]
- Med Klin Intensivmed Notfmed 2014 Nov 5.
The prognosis of patients who have been resuscitated after cardiac arrest is still unfavourable and long-term results have only slightly improved. As a consequence, intensivists are frequently confronted with the question of limiting active therapeutic efforts for patients in prolonged coma. The history of the patient and circumstances of the resuscitation are of limited value with regard to reliable decisions.Clinical and electrophysiological neurologic techniques as well as biomarkers and diagnostic imaging are, therefore, the basis for prognostication and potential consecutive therapeutic decisions. Sedation, relaxation and particularly therapeutic hypothermia have great influence on the test results. These influences have to be excluded before results can be validated. With regard to therapeutic hypothermia a reliable neurologic evaluation as a basis for limiting treatment is only possible after rewarming. Moreover results of multiple tests should be in agreement before a decision to limit treatment can be made. Finally it must be kept in mind that the absence of unfavourable test results is not proof of a good prognosis.The decision to limit treatment can not be made on the basis of a single adverse prognostic sign, but requires a comprehensive clinical diagnostic assessment.