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- Hypothermia-induced acute kidney injury in an elderly patient. [Journal Article]
- Korean J Intern Med 2014 Jan; 29(1):111-5.
Hypothermia, defined as an unintentional decline in the core body temperature to below 35℃, is a life-threatening condition. Patients with malnutrition and diabetes mellitus as well as those of advanced age are at high risk for accidental hypothermia. Due to the high mortality rates of accidental hypothermia, proper management is critical for the wellbeing of patients. Accidental hypothermia was reported to be associated with acute kidney injury (AKI) in over 40% of cases. Although the pathogenesis remains to be elucidated, vasoconstriction and ischemia in the kidney were considered to be the main mechanisms involved. Cases of AKI associated with hypothermia have been reported worldwide, but there have been few reports of hypothermia-induced AKI in Korea. Here, we present a case of hypothermia-induced AKI that was treated successfully with rewarming and supportive care.
- Cold-induced vasoconstriction may persist long after cooling ends: an evaluation of multiple cryotherapy units. [JOURNAL ARTICLE]
- Knee Surg Sports Traumatol Arthrosc 2014 Feb 23.
Localized cooling is widely used in treating soft tissue injuries by modulating swelling, pain, and inflammation. One of the primary outcomes of localized cooling is vasoconstriction within the underlying skin. It is thought that in some instances, cryotherapy may be causative of tissue necrosis and neuropathy via cold-induced ischaemia leading to nonfreezing cold injury (NFCI). The purpose of this study is to quantify the magnitude and persistence of vasoconstriction associated with cryotherapy.Data are presented from testing with four different FDA approved cryotherapy devices. Blood perfusion and skin temperature were measured at multiple anatomical sites during baseline, active cooling, and passive rewarming periods.Local cutaneous blood perfusion was depressed in response to cooling the skin surface with all devices, including the DonJoy (DJO, p = 2.6 × 10(-8)), Polar Care 300 (PC300, p = 1.1 × 10(-3)), Polar Care 500 Lite (PC500L, p = 0.010), and DeRoyal T505 (DR505, p = 0.016). During the rewarming period, parasitic heat gain from the underlying tissues and the environment resulted in increased temperatures of the skin and pad for all devices, but blood perfusion did not change significantly, DJO (n.s.), PC300 (n.s.), PC500L (n.s.), and DR505 (n.s.).The results demonstrate that cryotherapy can create a deep state of vasoconstriction in the local area of treatment. In the absence of independent stimulation, the condition of reduced blood flow persists long after cooling is stopped and local temperatures have rewarmed towards the normal range, indicating that the maintenance of vasoconstriction is not directly dependent on the continuing existence of a cold state. The depressed blood flow may dispose tissue to NFCI.
- [Anchor Fast endotracheal tube securing device for a pediatric patient during therapeutic hypothermia]. [English Abstract, Journal Article]
- Masui 2014 Jan; 63(1):84-7.
A 5-year-old girl was admitted to our hospital after resuscitation from cardiac arrest due to near-drowning accident in a river. On admission, Glasgow Coma Scale score was 7; arterial blood pressure was 113/73 mm Hg; heart rate was 157 beats x min(-1), and percutaneous oxygen saturation was 99% on 10 l x min(-1) of oxygen. The patient was intubated with a 5.0 mm internal diameter endotracheal tube, and therapeutic hypothermia was started for neural protection. Hypothermia in the target temperature of 34 degrees C was maintained for 24 hours using Arctic Sun System. Although the patient had been sedated with fentanyl 0.6-1.2 microg x kg(-1) x hr(-1), midazolam 0.2-0.4 mg x kg(-1) x hr(-1) and dexmedetomidine 0.6-1.0 mirog x kg(-1) x hr(-1), agitation increased during the rewarming period following hypothermia. To avoid accidental extubation, we used Anchor Fast as a device for securing oral endotracheal tube. Anchor Fast kept the tube position properly even though the patient was turned or moved. Seventy-two hours later, she was rewarmed and extubated as scheduled. Ten days after admission, she was discharged without any neurological deficits.
- The effect of deep hypothermia on the human pulmonary circulation. [Journal Article]
- J Therm Biol 2014 Feb.:20-4.
Acute rises in pulmonary artery pressures following complex cardiac surgery are associated with high morbidity and mortality. We hypothesised that periods of deep hypothermia predispose to elevated pulmonary pressures upon rewarming. We investigated the effect of this hypothermic preconditioning on isolated human pulmonary arteries and isolated perfused lungs.Isometric tension was measured in human pulmonary artery rings (n=24). We assessed the constriction and dilation of these arteries at 37°C and 17°C. Isolated perfused human lung models consisted of lobes ventilated via a bronchial cannula and perfused with Krebs via a pulmonary artery cannula. Bronchial and pulmonary artery pressures were recorded. We investigated the effect of temperature using a heat exchanger.Rewarming from 17°C to 37°C caused a 1.3 fold increase in resting tension (p<0.05). Arteries constricted 8.6 times greater to 30nM KCl, constricted 17 times greater to 1nM Endothelin-1 and dilated 30.3 times greater to 100μM SNP at 37°C than at 17°C (p<0.005). No difference was observed in the responses of arteries originally maintained at 37°C compared to those arteries maintained at 17°C and rewarmed to 37°C. Hypothermia blunted the increase in pulmonary artery pressures to stimulants such as potassium chloride as well as to H-R but did not precondition arteries to higher pulmonary artery pressures upon re-warming.Deep hypothermia reduces the responsiveness of human pulmonary arteries but does not, however, precondition an exaggerated response to vasoactive agents upon re-warming.
- Numerical simulation of the effect of superparamagnetic nanoparticles on microwave rewarming of cryopreserved tissues. [JOURNAL ARTICLE]
- Cryobiology 2014 Feb 13.
In this study, the microwave rewarming process of cryopreserved samples with embedded superparamagnetic (SPM) nanoparticles was numerically simulated. The Finite Element Method (FEM) was used to calculate the coupling of the electromagnetic field and the temperature field in a microwave rewarming system composed of a cylindrical resonant cavity, an antenna source, and a frozen sample phantom with temperature-dependent properties. The heat generated by the sample and the nanoparticles inside the electromagnetic field of the microwave cavity was calculated. The dielectric properties of the biological tissues were approximated using the Debye model, which is applicable at different temperatures. The numerical results showed that, during the rewarming process of the sample phantom without nanoparticles, the rewarming rate was 29.45°C/min and the maximum temperature gradient in the sample was 3.58°C/mm. If nanoparticles were embedded in the sample, and the cavity power was unchanged, the rewarming rate was 47.76°C/min and the maximum temperature gradient in the sample was 1.64°C/mm. In the presence of SPM nanoparticles, the rewarming rate and the maximum temperature gradient were able to reach 20.73°C/min and 0.68°C/mm at the end of the rewarming under the optimized cavity power setting, respectively. The ability to change these temperature behaviors may prevent devitrification and would greatly diminish thermal stress during the rewarming process. The results indicate that the rewarming rate and the uniformity of temperature distribution are increased by nanoparticles. This could be because nanoparticles generated heat in the sample homogeneously and the time-dependent parameters of the sample improved after nanoparticles were homogeneously embedded within it. We were thus able to estimate the positive effect of SPM nanoparticles on microwave rewarming of cryopreserved samples.
- Effect of temperature on thromboelastography and implications for clinical use in neonates undergoing therapeutic hypothermia. [JOURNAL ARTICLE]
- Pediatr Res 2014 Feb 12.
Background:Encephalopathic neonates undergoing therapeutic hypothermia have increased risk for coagulopathy secondary to perinatal asphyxia and effects of cooling on the coagulation enzyme cascade. Thromboelastography (TEG) allows for a comprehensive assessment of coagulation that can be regulated for temperature. TEG has not been previously evaluated in newborns undergoing hypothermia treatment.Methods:Encephalopathic neonates treated with systemic hypothermia were enrolled in this prospective observational study. Daily blood specimens were collected for standard coagulation tests and platelet counts during hypothermia and after rewarming. Concurrent TEG assays were performed at 33.5 and 37.0 °C for comparison.Results:A total of 48 paired TEGs from 24 subjects were performed. Forty percent of the subjects were males, the mean (± SD) birth weight was 3.2 ± 0.7 kg, and the mean gestational age was 38.4 ± 1.4 wk. TEG results differed significantly between assays performed at 37.0 vs. 33.5 °C, indicating more impaired coagulation at 33.5 °C. TEG parameters clot kinetics, angle, maximum amplitude (MA), and coagulation index were significantly associated with clinical bleeding (P < 0.05). These remained significant (except for MA) after controlling for transfusion therapy.Conclusion:TEG results are affected by temperature, consistent with the known association of hypothermia with coagulopathy. Several TEG parameters are predictive of clinical bleeding in newborns undergoing hypothermia. Selected cutpoints to predict bleeding risk are temperature dependent.Pediatric Research (2014); doi:10.1038/pr.2014.19.
- A double-blind, randomized, placebo-controlled crossover trial of the α2C-adrenoceptor antagonist ORM-12741 for prevention of cold-induced vasospasm in patients with systemic sclerosis. [JOURNAL ARTICLE]
- Rheumatology (Oxford) 2014 Jan 31.
Objectives. Our primary purpose was to evaluate the efficacy of the high-potency α2C-adrenoceptor antagonist ORM-12741 in the attenuation of a cold-induced reduction in finger blood flow and temperature in patients with RP secondary to SSc. Secondary objectives were to assess safety and tolerability.Methods. This was a phase IIa, randomized, double-blind, crossover, single-dose, placebo-controlled, single-centre study. Patients attended five times: initial screening, treatment visits 1-3 (each at least 1 week apart) and 1-2 weeks after the last treatment. At each treatment visit, each subject received a single oral dose of 30 mg or 100 mg of ORM-12741 or placebo. Thirty minutes later the subject underwent a cold challenge. Blood flow to the fingers was assessed by three methods [temperature by probe, laser Doppler imaging (LDI) and infrared thermography] performed before, during and after the cold challenge.Results. Twelve patients (10 female, mean age 58 years) were included. The area under the rewarming curve (LDI) of the right index finger (arbitrary flux units × time) was lower for both 30 mg (P = 0.043) and 100 mg (P = 0.025) of ORM-12741 compared with placebo, indicating delayed reperfusion. The time to 70% temperature recovery (middle finger probe) was longer with active than placebo treatment: mean (s.d.) values for placebo, 30 mg of ORM-12741 and 100 mg of ORM-12741 were 21.4 min (12.4), 25.7 min (12.2) and 26.9 min (13.9), respectively. Overall ORM-12741 was well tolerated.Conclusions. ORM-12741 did not expedite recovery from a cold challenge in the fingers of patients with SSc.Trial registration: https://www.clinicaltrialsregister.eu/; no. 2010-024005-13.
- Targeted temperature management after intracerebral hemorrhage (TTM-ICH): methodology of a prospective randomized clinical trial. [JOURNAL ARTICLE]
- Int J Stroke 2014 Jan 22.
Intracerebral hemorrhage causes 15% of strokes annually in the United States, and there is currently no effective therapy.This is a clinical trial designed to study the safety, feasibility, and efficacy of a protocol of targeted temperature management to moderate hypothermia in intracerebral hemorrhage patients.The targeted temperature management after intracerebral hemorrhage trial is a prospective, single-center, interventional, randomized, parallel, two-arm (1:1) phase-II clinical trial with blinded end-point ascertainment. Intracerebral hemorrhage patients will be randomized within 18 h of symptom onset to either 72 h of targeted temperature management to moderate hypothermia (32-34°C) followed by a controlled rewarming at of 0·05-0·1°C per hour or 72 h of targeted temperature management to normothermia (36-37°C) using endovascular or surface cooling.The primary outcome is the development of serious adverse events possibly and probably related to treatment. Secondary outcomes include in-hospital neurological deterioration between day 0-7, in-hospital mortality, functional outcome measured by the modified Rankin scale at discharge and 90 days, and effect of treatment allocation on cerebral edema and hematoma volume.Intracerebral hemorrhage remains the most severe form of stroke with limited options to improve survival. As the early resuscitation phase in the intensive care unit represents the greatest opportunity for impact on clinical outcome, it also appears to be the most promising window of opportunity to demonstrate a benefit when investigating aggressive treatments.More research of novel therapies to improve outcomes after intracerebral hemorrhage is desperately needed. The results of the targeted temperature management after intracerebral hemorrhage clinical trial may provide additional information on the applicability of targeted temperature management after intracerebral hemorrhage.
- Cerebral blood flow autoregulation is preserved after hypothermic circulatory arrest. [Comparative Study, Journal Article, Research Support, Non-U.S. Gov't]
- Ann Thorac Surg 2013 Dec; 96(6):2045.
Patients undergoing aortic operations with hypothermic circulatory arrest (HCA) may require prolonged rewarming, a maneuver associated with impaired cerebral blood flow (CBF) autoregulation. The purpose of this study was to determine the effects of HCA on CBF autoregulation with a validated method based on near-infrared spectroscopy.Regional cerebral oxygen saturation (rSco2) was monitored in 25 patients undergoing aortic reconstructive operations. HCA was used in 13 patients. Autoregulation was measured continuously during the operation by calculating the linear correlation coefficient between low-frequency changes in rSco2 and mean arterial pressure (MAP), generating the variable cerebral oximetry index (COx). When CBF autoregulation is functional, COx is near 0, because CBF and MAP are not correlated, but approaches 1 when autoregulation is impaired (ie, CBF is pressure passive). On the basis of prior studies, impaired autoregulation was defined as COx exceeding 0.3.COx did not differ between HCA and non-HCA groups before cardiopulmonary bypass or during the cooling phase of the operation, although the lower limit of autoregulation tended to be lower in patients before HCA (p = 0.053). During patient rewarming, COx was lower in the HCA group (p = 0.045), and abnormal COx was less frequent (31% vs 75%, p = 0.047) compared with the non-HCA group.During aortic reconstructive operations, CBF autoregulation is preserved during the cooling phase of the procedure in patients undergoing HCA. Perfusion maneuvers associated with HCA may be protective against impaired autoregulation during rewarming compared with the non-HCA group.
- Platelet dysfunction as measured by a point-of-care monitor is an independent predictor of high blood loss in cardiac surgery. [Journal Article, Research Support, Non-U.S. Gov't]
- Anesth Analg 2014 Feb; 118(2):257-63.
Excessive bleeding carries a heavy burden of illness in cardiac surgery. Although platelet dysfunction is considered to be an important cause, it is not routinely measured. Our objective was to explore the relationship between platelet dysfunction and blood loss in cardiac surgery.In 100 consenting patients undergoing cardiac surgery requiring cardiopulmonary bypass, platelet function was measured before, during, and after bypass with a point-of-care device that compares platelet counts before and after exposure to an agonist. Clinicians were blinded to the results of testing. Patients whose calculated blood loss was part of the highest quartile for the cohort were classified as having had high blood loss. The independent relationship between platelet function and high blood loss was measured with the aid of multivariable Poisson regression modeling (with a robust error variance) that controlled for patients' overall risk of high blood loss.Calculated blood loss was negatively skewed with a median of 798 mL (25th and 75th percentiles of 380 and 1775 mL). Patients whose blood loss exceeded 1770 mL were classified as having had high blood loss, and 25 patients met this criterion. There was 1 death in the high blood loss group unrelated to hemorrhage. After adjusting for bleeding risk, each 10 × 10/L increase in collagen-activated functional platelet count during rewarming and postprotamine, respectively, was associated with a relative risk of 0.89 (95% confidence interval, 0.82-0.97; P = 0.006) and 0.87 (95% confidence interval, 0.78-0.98; P = 0.02) for high blood loss.Platelet dysfunction, as measured by a point-of-care method during rewarming and postprotamine, is independently associated with high blood loss in cardiac surgery. Additional studies are needed to determine whether the incorporation of this assay into blood management algorithms might help rationalize blood transfusion therapy, potentially reducing blood loss and improving clinical outcomes.