Objective To systematically review the effectiveness of forced air warming for the maintenance of perioperative core temperature, so as to provide clinical evidence for an appropriate warming plan during the perioperative period. Methods We electronically searched PubMed, The Cochrane Library, EMbase, Web of Science, CBM and CNKI from 2000 to 2012, so as to comprehensively collect randomized controlled trials (RCTs) about the effectiveness of different warming methods for the maintenance of perioperative core temperature (including forced air warming, resistive-heating blanket/electric heating pad, circulating water mattress, and infrared ray radiant heating system) for maintenance of perioperative core temperature. References of the included studies were also retrieved. Two reviewers independently screened literature according to the inclusion and exclusion criteria, extracted data and assessed the quality of the included studies. Then, meta-analysis was performed using RevMan 5.1 software. Results Eleven RCTs involving 577 patients were included. The results of meta-analysis indicated that, in the maintenance of core temperature during the perioperative period, forced air warming was superior to resistive-heating blanket/electric heating pad (SMD= –0.40, 95%CI –0.73 to –0.06), circulating water mattress (SMD= –1.10, 95%CI –1.55 to –0.66), and infrared ray radiant heating system (SMD= –0.69, 95%CI –1.06 to –0.32). In the incidence of hypothermia during the perioperative period, the group of forced air warming was lower than the group of blanket/electric heating pad (RR=1.76, 95%CI 1.15 to 2.69), but it was the same as the group of infrared ray radiant heating system (RR=1.37, 95%CI 0.83 to 2.27). In the incidence of shivering during the perioperative period, the group of forced air warming was the same as the group of blanket/electric heating pad (RR=0.75, 95%CI 0.18 to 3.21) and the group of infrared ray radiant heating system (RR=0.8, 95%CI 0.19 to 3.36). Conclusion Compared with resistive-heating blanket/electric heating pad, circulating water mattress, and infrared ray radiant heating system, forced air warming maintains patients’ core temperature better during the perioperative period, with a lower incidences of hypothermia. Due to the limited quantity and quality of the included studies, more high quality RCTs with large sample size are needed to verify the above conclusion.
【Abstract】Objective To study the mechanisms of enhancing effect of mild hypothermia (MH) to ischemic preconditioning (IP) on hepatic ischemiareperfusion (I-R) injury. Methods To observe the content of the marker enzymes of liver damage (ALT,AST,LDH) and malondialdehyde (MDA), and activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPX), total antioxidase (TAX) in inferior vena cava blood above liver in nonischemic control group (n=6), I-R group (n=6), IP group (n=6) and mild hypothermic ischemic preconditioning (MHIP) group (n=6). Results After I-R the content of ALT,AST, LDH and MDA were significantly elevated (P＜0.01), SOD,CAT,GSH-PX,ACT activities were declined obviously (P＜0.01). The content of ALT,AST,LDH and MDA were significantly lower in IP group than those in I-R group, and in MHIP group than those in IP group (P＜0.01,P＜0.05), and the content of SOD, CAT,GSH-PX, ACT activities were significantly higher in IP group than those in I-R group, and in MHIP group than those in IP group (P＜0.01,P＜0.05). Conclusion Ischemic preconditioning may enhance the oxidation-resistance of liver, and reduce the oxygen free radical injury to liver after ischemia-reperfusion. Mild hypothermia may enhance the protective effect of IP on hepatic ischemiareperfusion injury.
OBJECTIVE: To investigate the mechanism and to explore the measures of prevention and treatment of hypothermal vasoconstriction. METHODS: By the techniques of endothelial cell culture and scanning electron microscopy, and vasomotor functional test of isolated vascular vessels, the relation of hypothermal vasoconstriction and the release of endothelium-derived contractile and vasodilative factors were observed. RESULTS: Hypothermia obviously induced vasoconstriction of isolated vascular vessels, whether endothelium was intact or removed, the lower the temperature, the higher the vascular tension. Removal of endothelium could decrease the effect of vasoconstriction by hypothermia. The conditioned medium of bovine aortic endothelial cell could induce significantly vasoconstriction of isolated rat common neck arterial ring in hypothermia. It indicated that the bovine aortic endothelial cells secreted contractile factors into the medium. Reheating to 37 degrees C or vasodilator or reheating plus vasodilator did not obviously influence the hypothermia-induced vasoconstriction within 2 hours. When reheating to 50 degrees C, vascular tension was decreased, but only changed in range of 28% to 42%. CONCLUSION: Hypothermia vasoconstriction is relative to vasoconstrictor factors secreted by endothelium. Reheating to 37 degrees C or vasodilator does not antagonize the constriction of vascular vessels. Reheating to 50 degrees C only partially eliminates the constrict effect of blood vessels, so the prevention of hypothermia vasoconstriction should be emphasized.
Local hypothermia as a preventive method to reperfusion injury of skeletal muscles was studied. Sixteen Japanese rabbits were divided into four groups at random. Before the tourniquet was inflated, a cold gel pack was applied to the right hind leg of each rabbit for 15 minutes to produce local hypothermic condition, without application of tourniquet the left hind limb was under local hypothermic condition as a control. The duration of tourniquet ischemia was 4 hours, and then reperfusion for one and two hours in the A and B groups respectively; in the C and D groups the duration of ischemia was 5 hours, and reperfusion for one and two hours, respectively. The muscle temperature averaged 16.6 degrees C with a needle thermocouple in the hind limb under local hypothermia. The serum K+, LA, SOD, LPO were determined from bilateral femoral veins, and electron and light microscopic studies of sural muscles were done in the post-reperfusion period. It was found that the K+, LA, LPO were lower than that of the control groups (P lt; 0.01), but SOD was higher than that of the control group (P lt; 0.01). Electron and light microscopic studies showed sight but reversible damage of muscular structure with the possibility of in the hypothermic groups cell regeneration. Basing on this experimental results, this method was applied in 45 cases reparative and reconstructive surgery of limbs. The duration of application of tourniquet averaged 2 hours and 57 minutes, the longest being 4 hours and 31 minutes, when the muscle temperature had reduced to 22.4 degrees C. There were no postoperative complications associated with this technique. Local hypothermia appeared to be a safe and effective method of decreasing the reperfusion damage after ischemia.
Objective To summarize the effect of mild hypothermia on post-cardiac surgery patients with multiple organ dysfunction system(MODS). Methods We retrospectively analyzed the clinical data of 90 patients with MODS after cardiac surgery under cardiopulmonary bypass(CPB) from May 2010 through June 2014 in our hospital. There were 57 males and 33 females at 61±6 years. The patients were divided into two groups including a NT group (without pre-hypothermia treatment,n=32) and a HT group(with pre-hypothermia treatment,n=58). Results Of the 90 patients, totally 18 patients died, 8 patients (13.8%) in the HT group, 10 patients (31.2%) in the NT group with a statistical difference (P<0.05). In the NT group, 12 patients (37.5%) were treated by intra-aortic balloon pump (IABP), and 9 patients (15.5%) in the HT group with a statistical difference between the two groups (P<0.05). The patients' heart rate (HR) decreased significantly after the application of hypothermia. The HR of difference between the two groups at 36 h was significant (P<0.05). The mean aortic pressure (MAP) in the HT group was lower than that of the NT group significantly at 0 h, because we used sedation and muscular relaxation agent. But the MAP in the HT group was significantly higher than that of the NT group after hypothermia 36 h (P<0.05). In the HT group, pressure of oxygen (PO2), mixed venous oxygen saturation (SvO2), and lactic acid (Lac) were improved significantly compared with those of the NT group significantly (P<0.05). There was no statistical difference in prothrombin time (PT) or activated partial thromboplastin time (APTT) between the two groups (P>0.05). But there was a statistical difference in platelet (PLT) between the two groups at 36 h (P<0.05). The aspartate aminotransferase (AST), alannine aminotransferase (ALT), creatinine (Cr) were improved significantly in the HT group (P<0.05). Conclusion Mild hypothermia can improve the organ function effectively. It can slow the MODS development speed and win the time of protection and further treatment for cells and organs. It is an effective and safety therapeutic technique for MODS after cardiac surgery.
ObjectivesTo systematically review the efficacy of hypothermia intervention on adult severe craniocerebral injury.MethodsCNKI, WanFang Data, VIP, CBM, PubMed, EMbase, Web of Science and The Cochrane Library databases were electronically searched to collect randomized controlled trials (RCTs) of hypothermia intervention on severe craniocerebral injury from the establishment of the database to July 2nd, 2020.Two reviewers independently screened literature, extracted data and assessed risk of bias of included studies, then, meta-analysis was performed by using RevMan 5.3 software.ResultsA total of 25 RCTs involving 2 949 patients were included. The results of meta-analysis showed that the mortality of hypothermia intervention group was lower than that of normal body temperature group (RR=0.72, 95%CI 0.58 to 0.89, P=0.003), and the prognosis of hypothermia intervention group was better than that of normal body temperature group (RR=1.29, 95%CI 1.15 to 1.46, P<0.000 1).ConclusionsCurrent evidence shows that the hypothermia intervention has a lower mortality rate and a higher prognosis rate in the treatment of adult severe brain injury. Due to limited quality and quantity of the included studies, more high quality studies are required to verify above conclusions.