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Microcirculatory effects of rewarming in experimental hemorrhagic shock. Microvasc Res 2023; 147:104490. [PMID: 36736659 DOI: 10.1016/j.mvr.2023.104490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 01/15/2023] [Accepted: 01/23/2023] [Indexed: 02/04/2023]
Abstract
BACKGROUND Rewarming is a recommended therapy during the resuscitation of hypothermic patients with hemorrhagic shock. In experimental models, however, it increases inflammatory response and mortality. Although microcirculation is potential target of inflammation, the microvascular effects of rewarming during the resuscitation of hemorrhagic shock have not been studied. Our goal was to assess the systemic and microcirculatory effects of an increase in core temperature (T°) during the retransfusion of hemorrhagic shock in sheep. Our hypothesis was that rewarming could hamper microcirculation. METHODS In anesthetized and mechanically ventilated sheep, we measured systemic, intestinal, and renal hemodynamics and oxygen transport. O2 consumption (VO2) and respiratory quotient were measured by indirect calorimetry. Cortical renal, intestinal villi and sublingual microcirculation were assessed by IDF-videomicroscopy. After basal measurements, hemorrhagic shock was induced and T° was reduced to ~33 °C. After 1 h of shock and hypothermia, blood was retransfused and Ringer lactate solution was administered to prevent arterial hypotension. In the control group (n = 12), T° was not modified, while in the intervention (rewarming) group, it was elevated ~3 °C. Measurements were repeated after 1 h. RESULTS During shock, both groups showed similar systemic and microvascular derangements. After retransfusion, VO2 remained decreased compared to baseline in both groups, but was lower in the control compared to the rewarming group. Perfused vascular density has a similar behavior in both groups. Compared to baseline, it remained reduced in peritubular (control vs. rewarming group, 13.8 [8.7-17.5] vs. 15.7 [10.1-17.9] mm/mm2, PNS) and villi capillaries (14.7 [13.6-16.8] vs. 16.3 [14.2-16.9] mm/mm2, PNS), and normalized in sublingual mucosa (19.1 [16.0-20.3] vs. 16.6 [14.7-17.2] mm/mm2, PNS). CONCLUSIONS This is the first experimental study assessing the effect of rewarming on systemic, regional, and microcirculatory perfusion in hypothermic hemorrhagic shock. We found that a 3 °C increase in T° neither improved nor impaired the microvascular alterations that persisted after retransfusion. In addition, sublingual mucosa was less susceptible to reperfusion injury than villi and renal microcirculation.
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Increased PINK1/Parkin-mediated mitophagy explains the improved brain protective effects of slow rewarming following hypothermia after cardiac arrest in rats. Exp Neurol 2020; 330:113326. [DOI: 10.1016/j.expneurol.2020.113326] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 04/13/2020] [Accepted: 04/19/2020] [Indexed: 12/06/2022]
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Hypothermia-rewarming: A Double-edged sword? Med Hypotheses 2019; 133:109387. [PMID: 31541781 DOI: 10.1016/j.mehy.2019.109387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 08/27/2019] [Accepted: 08/29/2019] [Indexed: 01/05/2023]
Abstract
Hypothermia is a condition in which the body's core temperature drops below 35.0 °C. Hypothermia is the opposite of hyperthermia, which the metabolism and body functions are abnormal. Severe hypothermia is a life-threatening problem that may cause atrial and ventricular dysrhythmias, coagulopathy, cardiac, and central nervous system depression. What is worse, it is fatal when untreated or treated improperly. Accidental deaths due to hypothermia resulting from immersion in cold water, especially involving naval fighters and maritime victims have occurred continually in the past years. Currently, the treatment of hypothermia has become a research focus. Rewarming is the only approach that should be considered for hypothermia treatment. However, the treatment is of low efficiency, and few active rewarming cases have been reported. It is well known that timely reperfusion is the best way to save the lives of patients with ischemia. Similarly, reoxygenation is effective for hypoxia. However, several studies have identified that improper reperfusion of ischemic tissues and reoxygenation of hypoxic tissues give rise to further injury. Analogically, this study attempts to propose the hypothesis that hypothermia-rewarming injury may also exist. When suffered from hypothermia, both the blood circulation and the oxygen supply in the body will be affected in a deficient state, an injury may also appear in the improper rewarming process. In a word, hypothermia-rewarming may be a double-edged sword.
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Hifumi T, Inoue A, Kokubu N, Hase M, Yonemoto N, Kuroda Y, Kawakita K, Sawano H, Tahara Y, Nishioka K, Shirai S, Hazui H, Arimoto H, Kashiwase K, Kasaoka S, Motomura T, Yasuga Y, Yokoyama H, Nagao K, Nonogi H. Association between rewarming duration and neurological outcome in out-of-hospital cardiac arrest patients receiving therapeutic hypothermia. Resuscitation 2019; 146:170-177. [PMID: 31394154 DOI: 10.1016/j.resuscitation.2019.07.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 07/23/2019] [Accepted: 07/26/2019] [Indexed: 02/08/2023]
Abstract
AIM The European Resuscitation Council guidelines recommend a slow rate of rewarming of 0.25 °C/h-0.5 °C/h for out-of-hospital cardiac arrest (OHCA) patients receiving therapeutic hypothermia (TH). Conversely, a very slow rewarming of 1 °C/day is generally applied in Japan. The rewarming duration ranged from less than 24 h up to more than 50 h. No randomized control trials have examined the optimal rewarming speed for TH in OHCA patients. Therefore, we examined the association between the rewarming duration and neurological outcomes in OHCA patients who received TH. METHODS This study was a secondary analysis of the Japanese Population-based Utstein-style study with defibrillation and basic/advanced Life Support Education and implementation-Hypothermia (J-PULSE-HYPO) study registry, a multicenter prospective cohort study. Patients suffering from OHCA who received TH (target temperature, 34 °C) after the return of spontaneous circulation from 2005 to 2011 in 14 hospitals throughout Japan were enrolled. The rewarming duration was defined as the time from the beginning of rewarming at a target temperature of 34 °C until reaching 36 °C. The primary outcome was an unfavorable neurological outcome at hospital discharge, i.e., a cerebral performance category of 3-5. RESULTS The J-PULSE-HYPO study enrolled 452 OHCA patients. Of these, 328 were analyzed; 79.9% survived to hospital discharge, of which 56.4% had a favorable neurological outcome. Multivariable logistic regression analysis revealed that the rewarming duration was independently associated with unfavorable neurological outcomes [odds ratio (per 5 h), 0.89; 95% confidence interval, 0.79-0.99; p = 0.032]. CONCLUSION A longer rewarming duration was significantly associated with and was an independent predictor of favorable neurological outcomes in OHCA patients who received TH.
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Affiliation(s)
- Toru Hifumi
- Department of Emergency and Critical Care Medicine, St. Luke's International Hospital, Japan; Emergency Medical Center, Kagawa University Hospital, Japan.
| | - Akihiko Inoue
- Emergency Medical Center, Kagawa University Hospital, Japan; Department of Emergency and Critical Care Medicine, Hyogo Emergency Medical Center, Japan
| | - Nobuaki Kokubu
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University, Japan
| | | | - Naohiro Yonemoto
- Department of Biostatistics, Kyoto University School of Public Health, Japan
| | | | - Kenya Kawakita
- Emergency Medical Center, Kagawa University Hospital, Japan
| | - Hirotaka Sawano
- Senri Critical Care Medical Center, Saiseikai Senri Hospital, Japan
| | - Yoshio Tahara
- Division of Cardiovascular Care Unit, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Japan
| | - Kenji Nishioka
- Department of Cardiology, Hiroshima City Hospital, Japan
| | | | - Hiroshi Hazui
- Emergency Medicine, Osaka Mishima Emergency and Critical Care Center, Japan
| | - Hideki Arimoto
- Emergency and Critical Care Medical Center, Osaka City General Hospital, Japan
| | - Kazunori Kashiwase
- Department of Internal Medicine, Division of Coronary Heart Disease, Hyogo College of Medicine, Japan
| | - Shunji Kasaoka
- Department of Emergency and General Medicine, Kumamoto University Hospital, Japan
| | - Tomokazu Motomura
- Shock & Trauma Center, Chiba Hokusoh Hospital, Nippon Medical School, Japan
| | - Yuji Yasuga
- Department of Cardiology, Sumitomo hospital, Japan
| | | | - Ken Nagao
- Cardiovascular Center, Nihon University Hospital, Japan
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Hayek AJ, White HD, Ghamande S, Spradley C, Arroliga AC. Is Therapeutic Hypothermia for Acute Respiratory Distress Syndrome the Future? J Intensive Care Med 2017; 32:460-464. [PMID: 28343415 DOI: 10.1177/0885066617701117] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Severe acute respiratory distress syndrome (ARDS) has a high mortality, and there is limited knowledge about management of severe ARDS refractory to standard therapy. Early evidence suggests that therapeutic hypothermia (TH) could be a viable treatment for acute respiratory failure. We present 2 cases where TH was successfully used to manage refractory ARDS on extracorporeal membrane oxygenation (ECMO) and a review of the literature around TH and acute respiratory failure. RESULTS We present 2 cases of ARDS secondary to H1N1 influenza and human metapneumovirus. Both patients were treated with the current evidence-based therapy for ARDS. Venovenous ECMO was used in both patients for refractory hypoxemia. Therapeutic hypothermia was applied for 24 hours with improved oxygenation. We did a review of the literature summarizing 38 patients in 10 publications where TH was successfully utilized in the treatment of acute respiratory failure. CONCLUSION Therapeutic hypothermia may be a viable salvage therapy for ARDS refractory to the current evidence-based therapy but needs further evaluation.
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Affiliation(s)
- Adam J Hayek
- 1 Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Baylor Scott & White Health, Temple, TX, USA
| | - Heath D White
- 1 Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Baylor Scott & White Health, Temple, TX, USA
| | - Shekhar Ghamande
- 1 Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Baylor Scott & White Health, Temple, TX, USA
| | - Christopher Spradley
- 1 Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Baylor Scott & White Health, Temple, TX, USA
| | - Alejandro C Arroliga
- 1 Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Baylor Scott & White Health, Temple, TX, USA
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Kalimeris K, Briassoulis P, Ntzouvani A, Nomikos T, Papaparaskeva K, Politi A, Batistaki C, Kostopanagiotou G. N-acetylcysteine ameliorates liver injury in a rat model of intestinal ischemia reperfusion. J Surg Res 2016; 206:263-272. [DOI: 10.1016/j.jss.2016.08.049] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/07/2016] [Accepted: 08/10/2016] [Indexed: 02/07/2023]
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Jo YH, Kim K, Lee JH, Rim KP, Cho IS. Rapid rewarming after therapeutic hypothermia worsens outcome in sepsis. Clin Exp Emerg Med 2014; 1:120-125. [PMID: 27752563 PMCID: PMC5052836 DOI: 10.15441/ceem.14.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 07/05/2014] [Accepted: 07/17/2014] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE This study was performed to investigate the effect of the rewarming rate on survival and acute lung injury in sepsis. METHODS Male Sprague-Dawley rats underwent cecal ligation and incision. After 1 hour of sepsis induction, normothermia (37°C±0.5°C, NT group) or hypothermia (32°C±0.5°C) was induced. Hypothermia was maintained for 4 hours and rats were divided into two groups according to the rewarming rate: RW1 group, 1 hour of rewarming; and RW2 group, 2 hours of rewarming. In the survival study, rats were observed for 12 hours after sepsis induction (n=6 per group). In the second experiment, rats were sacrificed 7 hours after sepsis induction, and lung tissues and plasma were harvested (n=10 per group). RESULTS In the survival study, the RW2 group survived longer than the RW1 group (P<0.05), but the RW1 and NT groups showed no significant difference in survival duration (P>0.05). The histological lung injury score and malondialdehyde concentrations in the lung tissues were significantly higher in the RW1 group than in the RW2 group (P<0.05). Plasma interleukin (IL)-6 concentration and the ratio of IL-6 to IL-10 were higher in the RW1 group than in the RW2 group (P<0.05). CONCLUSION Rapid rewarming after therapeutic hypothermia results in a shorter survival period and acute lung injury in sepsis, which could be associated with the inflammatory responses.
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Affiliation(s)
- You Hwan Jo
- Department of Emergency Medicine, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Kyuseok Kim
- Department of Emergency Medicine, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Jae Hyuk Lee
- Department of Emergency Medicine, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Kwang Pil Rim
- Department of Emergency Medicine, St. Carollo General Hospital, Suncheon, Korea
| | - In Soo Cho
- Department of Emergency Medicine, Kepco Medical Center, Seoul, Korea
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Lee JH, Kim K, Jo YH, Kim MA, Rim KP, Kang KW, Rhee JE, Lee MJ, Lee HS, Kwon WY, Suh GJ. Therapeutic hypothermia attenuates liver injury in polymicrobial sepsis model of rats via Akt survival pathway. J Surg Res 2013; 181:114-20. [DOI: 10.1016/j.jss.2012.05.045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 05/03/2012] [Accepted: 05/10/2012] [Indexed: 01/09/2023]
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Rim KP, Kim K, Jo YH, Lee JH, Rhee JE, Kang KW, Suh GJ, Kwon WY, Lee MJ, Lee HS. Effect of therapeutic hypothermia according to severity of sepsis in a septic rat model. Cytokine 2012; 60:755-61. [PMID: 22980485 DOI: 10.1016/j.cyto.2012.08.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 07/26/2012] [Accepted: 08/13/2012] [Indexed: 11/19/2022]
Abstract
AIM OF STUDY The effects of therapeutic hypothermia (HT) during experimental sepsis may be influenced by disease severity. We experimentally investigated the effect of therapeutic HT on varying disease severity in a septic rat model. MATERIALS AND METHODS An adult male Sprague-Dawley rat model of intra-abdominal sepsis was used. To modify the disease severity, we used two different models; a moderate severe sepsis model (MSSM) and a severe septic shock model (SSSM). All rats were randomized to a hypothermia group (HT, 30-32°C) or a normothermia group (NT, 36-38°C) 1h after sepsis induction in each model. HT was maintained for 4h and rewarming was conducted for 2h. Survival time was recorded for up to 12h in the SSSM group and 24h in the MSSM group. Acute lung and liver injury, cytokine, and malondialdehyde (MDA) levels were investigated 7h after sepsis induction. Hemodynamic profiles were also evaluated. RESULTS In the SSSM, there were survival benefits and reduced acute lung and liver injury with therapeutic HT. Therapeutic HT was also associated with significantly reduced levels of plasma interleukin-6 and tissue malondialdehyde (MDA) levels in the liver and lung compared with the NT group in the SSSM. There was a tendency for the mean arterial pressure to be higher in the HT group compared to the NT group in the SSSM. In MSSM, however, there was no such beneficial effect. CONCLUSION In this rat model of severe septic shock, therapeutic HT showed beneficial effects. In contrast, therapeutic HT did not show protective effect in the moderate sepsis model.
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Affiliation(s)
- Kwang Pil Rim
- Department of Emergency Medicine, Seoul Medical Center, 316 Sinnae-dong, Jungnang-gu, Seoul 131-130, Republic of Korea
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Saad KR, Saad PF, Dantas Filho L, Brito JMD, Koike MK, Zanoni FL, Dolhnikoff M, Montero EFDS. Pulmonary impact of N-acetylcysteine in a controlled hemorrhagic shock model in rats. J Surg Res 2012; 182:108-15. [PMID: 22883437 DOI: 10.1016/j.jss.2012.07.037] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 06/28/2012] [Accepted: 07/13/2012] [Indexed: 02/06/2023]
Abstract
BACKGROUND Experimental hemorrhagic shock (HS) is based on controlling bleeding and the treatment of fluid resuscitation to restore tissue oxygenation and perfusion. The HS could promote ischemia/reperfusion injury, which induces a general exacerbation of the inflammatory process, initially compromising the lungs. N-acetylcysteine (NAC), an antioxidant, may attenuate ischemia/reperfusion injury. This study evaluated the effect of NAC in association with fluid resuscitation on pulmonary injury in a controlled HS model in rats. METHODS Male Wistar rats were submitted to controlled HS (mean arterial pressure of 35 mm Hg for 60 min). Two groups were constituted according to resuscitation solution administered: RLG (Ringer's lactate solution) and RLG+NAC (Ringer's lactate in association with 150 mg/kg NAC. A control group was submitted to catheterization only. After 120 min of resuscitation, bronchoalveolar lavage was performed to assess intra-alveolar cell infiltration and pulmonary tissue was collected for assessment of malondialdehyde, interleukin 6, and interleukin 10 and histopathology. RESULTS Compared with the RLG group, the RLG+NAC group showed lower bronchoalveolar lavage inflammatory cell numbers, lower interstitial inflammatory infiltration in pulmonary parenchyma, and lower malondialdehyde concentration. However, tissue cytokine (interleukin 6 and interleukin 10) expression levels were similar. CONCLUSION N-acetylcysteine was associated with fluid resuscitation-attenuated oxidative stress and inflammatory cell infiltration in pulmonary parenchyma. N-acetylcysteine did not modify cytokine expression.
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Affiliation(s)
- Karen Ruggeri Saad
- Department of Surgery, Medical School, Federal University of São Paulo, São Paulo, Brazil
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Scaravilli V, Bonacina D, Citerio G. Rewarming: facts and myths from the systemic perspective. Crit Care 2012. [PMCID: PMC3389485 DOI: 10.1186/cc11283] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Schmutzhard E, Fischer M, Dietmann A, Helbok R, Broessner G. Rewarming: facts and myths from the neurological perspectives. Crit Care 2012. [PMCID: PMC3389484 DOI: 10.1186/cc11282] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Facts and fiction: the impact of hypothermia on molecular mechanisms following major challenge. Mediators Inflamm 2012; 2012:762840. [PMID: 22481864 PMCID: PMC3316953 DOI: 10.1155/2012/762840] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Accepted: 01/02/2012] [Indexed: 01/02/2023] Open
Abstract
Numerous multiple trauma and surgical patients suffer from accidental hypothermia. While induced hypothermia is commonly used in elective cardiac surgery due to its protective effects, accidental hypothermia is associated with increased posttraumatic complications and even mortality in severely injured patients. This paper focuses on protective molecular mechanisms of hypothermia on apoptosis and the posttraumatic immune response. Although information regarding severe trauma is limited, there is evidence that induced hypothermia may have beneficial effects on the posttraumatic immune response as well as apoptosis in animal studies and certain clinical situations. However, more profound knowledge of mechanisms is necessary before randomized clinical trials in trauma patients can be initiated.
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Minor T, Lüer B, Efferz P. Dopamine improves hypothermic machine preservation of the liver. Cryobiology 2011; 63:84-9. [DOI: 10.1016/j.cryobiol.2011.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 05/15/2011] [Accepted: 05/20/2011] [Indexed: 12/14/2022]
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Singer AJ, Wang E, Taira BR, Steinhauff N, Rooney J, Zimmerman T. Controlled mild hypothermia prolongs survival in a rat model of large scald burns. Acad Emerg Med 2011; 18:287-91. [PMID: 21352400 DOI: 10.1111/j.1553-2712.2011.01016.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Early surface cooling of burns reduces pain and depth of injury and improves healing. However, there are concerns that cooling of large burns may result in hypothermia and worsen outcomes. In contrast, controlled mild hypothermia improves outcomes after cardiac arrest and traumatic brain injury. The authors hypothesized that controlled mild hypothermia would prolong survival in a rat model of large scald burns. METHODS Thirty-six Sprague-Dawley rats (250-300 g) were anesthetized with 40 mg/kg intramuscular ketamine and 5 mg/kg xylazine, with supplemental inhalational isoflurane as needed. A single full-thickness scald burn covering 40% of total body surface area was created on each of the rats using a Mason-Walker template placed in boiling water (100 °C) for a period of 10 seconds. The rats were then randomized to hypothermia (n = 18) or no hypothermia (n = 18). Core body temperature was continuously monitored with a rectal temperature probe. In the experimental group, mild hypothermia was induced by applying ice packs over the prone rats until their rectal temperature was reduced by 2 °C for a period of 2 hours. After 2 hours of hypothermia, the rats were rewarmed back to their baseline temperature with a heating pad. The control rats were not cooled. The rats were monitored until death or for a period of 7 days, whichever was greater. The primary outcome was time to death. The difference in survival between the groups was determined using Kaplan-Meier analysis and the log-rank test. RESULTS Hypothermia was induced in all experimental rats within a mean of 22 minutes (95% confidence interval [CI] = 17 to 27). The numbers of nonhypothermic and hypothermic rats that were dead at each time point were as follows: 2 hours, five versus none; 18 hours, 16 versus five; 24 hours, 18 versus eight; and 48 hours, 18 versus 13 (p = 0.05). There were no additional deaths after 48 hours. The mean time to survival of the hypothermic rats was significantly greater than that of the nonhypothermic rats (p < 0.001). CONCLUSIONS Induction of brief, mild hypothermia prolongs survival and increases the survival rate in nonresuscitated rats with large scald burns.
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Affiliation(s)
- Adam J Singer
- Department of Emergency Medicine, Stony Brook University, Stony Brook, NY, USA.
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Jo YH, Kim K, Rhee JE, Suh GJ, Kwon WY, Na SH, Alam HB. Therapeutic hypothermia attenuates acute lung injury in paraquat intoxication in rats. Resuscitation 2011; 82:487-91. [PMID: 21236547 DOI: 10.1016/j.resuscitation.2010.11.028] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 10/25/2010] [Accepted: 11/26/2010] [Indexed: 12/18/2022]
Abstract
AIM OF THE STUDY Paraquat intoxication induces acute lung injury and numerous fatalities have been reported. The mechanism of toxic effect of paraquat is oxidative injury and inflammation. Therapeutic hypothermia has been known to have antioxidant and anti-inflammatory effects. This study was designed to evaluate the effect of therapeutic hypothermia on paraquat intoxication. METHODS Male Sprague-Dawley rats were given 50 mg/kg of paraquat intraperitoneally and divided into the normothermia (36-38°C) group and the hypothermia (30-32°C) group after 1h of paraquat administration. The hypothermia group underwent 2 h of hypothermia followed by 2 h of rewarming. In the survival study, mortality was observed for 24 h after paraquat administration. An in the second experiment, lung tissues and plasma were harvested at 6 h after paraquat administration. RESULTS The 12 h survival rate was significantly higher in the hypothermia group than in the normothermia group (100% vs. 50%, p<0.05), but survival rates for 24 h were not different. Acute lung injury score was lower in the hypothermia group than in the normothermia group (p<0.05). Thmalondialdehyde contents of lung tissues, plasma interleukin-6 and nitrite/nitrate concentrations were significantly decreased in the HT group compared to the NT group (p<0.05). CONCLUSION Therapeutic hypothermia delayed early mortality and attenuated acute lung injury in paraquat intoxication.
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Affiliation(s)
- You Hwan Jo
- Department of Emergency Medicine, Seoul National University Bundang Hospital, 166 Gumi-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 463-707, Republic of Korea
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