Acute kidney failure in hypothermia

Two cases with acute renal failure after prolonged hypothermia are presented. Both patients were found in come, became rapidly uremic and required hemodilaysis treatment. Although the laboratory findings were typical of severe muscle damage, e.g. elevated levels of serum creatinine phosphokinase, serum lactic dehydrogenase and serum aldolase activities, visible "crush-injuries" were not found. Acute renal failure was characterized by extreme catabolism and severe metabolic acidosis. After 4 and 10 hemodialyses respectively, the patients became polyuric and finally were discharges with normal renal and muscle function. Hypotension with diminished renal perfusion and nontraumatic rhabdomyolysis due to prolonged hypothermia are regarded as the dominant pathogenetic factors in the acute renal failure.     

EEG evaluation of patients undergoing extracorporeal circulation under analgesic and electrohypoalgesia with auricular acupuncture

Electroencephalograms recorded 12 hours before and 12 hours after heart surgery in ECC and moderate hypothermia (30 degrees) are evaluated. Two groups of patients were studied: - the first group was composed of those undergoing analgesic anaesthesia; - the second group of those undergoing electroencephalograms by means of auricular acupuncture. In the first group the postoperative EEG was dominated by long "theta" and "delta" waves characteristic of the deep sedation of analgesic anaesthesia. In the second the EEG displayed a "theta" rhythm interspersed with trains of "alpha" waves, similar to that of a tired, but alert person. The pathological traces with signs of diffused, hemispheric or cerebral distress, do not bear any relationship to the type of anaesthesia, but to the type of disease, which had increased the probability of thrombo-embolic, and/or ischaemic risk.     

Electrocardiographic abnormalities in combined hypercalcaemia and hypokalaemia--case report

A 47-year-old woman presented with extreme hypercalcaemia due to a parathyroid carcinoma. An electrocardiogram which was recorded when the hypercalcaemia was associated with hypokalaemia showed absence of the ST segment, prolonged T wave, a shortened QTac interval and prominent U waves.     

Review of Reinventing government.

Reviews the book, Reinventing government by David Osborn and Ted Gaebler (1992). This is a "must read" book for any consultant who works with or for government. The focus is on how government operates, the means of governing. Osborn and Gaebler point out that government cannot be run like a business, because they are fundamentally different institutions; their missions, motives and procedures being quite opposite. However, the differences between them do not mean that government cannot be more entrepreneurial, and that idea gets to the heart of the book. Control needs to be replaced by flexibility and adaptability. This can only happen if the environment is characterized by "entrepreneurship", which means "shifting economic resources out of an area of lower productivity into an area of higher productivity and greater yield". The authors propose 10 principles of new government, and the meat of the book is found in the ten chapters which expand on these ideas and offer a variety of examples. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bedside monitoring of the QT interval

Cardiac repolarization, represented on the ECG by the QT interval, is of particular clinical interest in critical care. Once it is measured and corrected for changes in heart rate, the QT interval is known as the QTc. Measurement of the QT interval is important because a prolonged QT interval is associated with ventricular tachycardia and sudden cardiac death. Despite the serious complications associated with a prolonged QT interval, the interval is not routinely measured because a standardized method for measuring it has not been established and the length of QT interval critical to the development of ventricular tachycardia has not been determined. Much has been written about the conditions associated with prolonged QT intervals and specific actions to take when complications appear. Guidelines to be used for QT analysis in the clinical area, based on currently available information, include (1) procedures for measuring QT interval and calculating QTc, (2) procedures for QT analysis, (3) warning signs that indicate increased risk of ventricular tachycardia associated with a prolonged QT interval, and (4) actions to consider once increased risk is determined.     

Human atrial repolarization: effects of sinus rate, pacing and drugs on the surface electrocardiogram

OBJECTIVES: We studied the effects of rate and some cardioactive drugs on the atrial surface electrocardiogram (ECG). BACKGROUND: In atrioventricular block, atrial surface ECG is unmasked. The effect of rate alone permits detection of the effect of other exogenous stimulations such as drugs in the presence of rate alterations. METHODS: High fidelity, high gain ECG leads I, II and III were recorded from 51 patients with heart block. Durations of P and Ta waves and the total PTa interval were measured from nonconducted atrial events. RESULTS: No relationship was found between sinus cycle length and PTa, P or Ta in 31 patients. In 20 patients, progressively decreasing the atrial pacing cycle length from 853 ms to 381 ms resulted in a linear reduction of the PTa interval from 444 to 291 ms (rho = 0.76, slope = 0.24). This was largely due to shortening of Ta. A linear rate correction formula was derived: corrected PTa = PTa - 0.24 (PP - 1000). Atropine (0.02 mg/kg) shortened the PP interval (p < 0.001) and the PTa interval (p < 0.01). Propranolol (0.1 mg/kg) prolonged the PP interval (p < 0.001) but did not alter the PTa interval. Neither disopyramide (2.0 mg/kg) nor flecainide acetate (2.0 mg/kg) altered the PP interval, but both prolonged the PTa interval (p < 0.001). This was largely due to P wave lengthening after flecainide (p < 0.001) and to Ta prolongation after disopyramide (p < 0.001). CONCLUSIONS: In heart block, PTa, P and Ta waves can be measured reliably. The effects of pacing and some antiarrhythmic drugs on the atrial myocardium are similar to those known at the ventricular level.     

Effect of the no-flow interval and hypothermia on cerebral blood flow and metabolism during cardiopulmonary resuscitation in dogs

BACKGROUND and PURPOSE: We sought (1) to determine the effect of brief periods of no flow on the subsequent forebrain blood flow during cardiopulmonary resuscitation (CPR) and (2) to test the hypothesis that hypothermia prevents the impact of the no-flow duration on cerebral blood flow (CBF) during CPR. METHODS: No-flow intervals of 1.5, 3, and 6 minutes before CPR at brain temperatures of 28 degreesC and 38 degreesC were compared in 6 groups of anesthetized dogs. Microsphere-determined CBF and metabolism were measured before and during vest CPR adjusted to maintain cerebral perfusion pressure at 25 mm Hg. RESULTS: Increasing the no-flow interval from 1.5 to 6 minutes at 38 degreesC decreased the CBF (18. 6+/-3.6 to 6.1+/-1.7 mL/100 g per minute) and the cerebral metabolic rate (2.1+/-0.3 to 0.7+/-0.2 mL/100 g per minute) during CPR. Cooling to 28 degreesC before and during the arrest eliminated the detrimental effects of increasing the no-flow interval on CBF (16. 8+/-1.0 to 14.8+/-1.9 mL/100 g per minute) and cerebral metabolic rate (1.1+/-0.1 to 1.3+/-0.1 mL/100 g per minute). Unlike the forebrain, 6 minutes of preceding cardiac arrest did not affect brain stem blood flow during CPR. CONCLUSIONS: Increasing the no-flow interval to 6 minutes in normothermic animals decreases the supratentorial blood flow and cerebral metabolic rate during CPR at a cerebral perfusion pressure of 25 mm Hg. Cooling to 28 degreesC eliminates the detrimental impact of the 6-minute no-flow interval on the reflow produced during CPR. The brain-protective effects of hypothermia include improving reflow during CPR after cardiac arrest. The effect of hypothermia and the impact of short durations of no flow on reperfusion indicate that increasing viscosity and reflex vasoconstriction are unlikely causes of the "no-reflow" phenomenon.     

Mammalian embryo: a model for congenital prolonged QT syndrome

The QT interval has been studied in ECG in mouse and rat embryos during two stages of development. The QT interval during the early stage of development is prolonged and an ST segment clearly exists. Both disappear during fetal development and do not exist in adult animals in which the T wave immediately follows the QRS. Mammalian embryos have therefore been proposed as a model for the study of QT prolongation. It is suggested that the origin of the QT prolongation in the young embryos is caused by the prolonged duration of the action potentials of the primordial cardiac tissue. During embryonic development this tissue becomes organized as a conductive system surrounded by "neomyocardial" tissue with a shorter duration of action potential, which causes the shorter QT interval at this stage. Our working hypothesis is that the pathogenesis of the prolonged QT syndrome in children could be interpreted as an incomplete or delayed differentiation between the primordial or primordial-like myocardium retaining prolonged action potential duration, and "neomyocardium" with short duration.     

Cause of death in men diagnosed with prostate carcinoma

Interrelations between QRS morphology, duration, and HV interval changes in a model of "complete" bundle branch block following right bundle branch radiofrequency ablation have not been subjected to systematic study. This article describes these interrelations in patients who underwent right bundle ablation. Over a period of 42 months, 16 patients underwent radiofrequency ablation of the right bundle for treatment of bundle branch reentrant tachycardia. All 16 patients had prolonged HV interval at baseline (minimum = 60 ms; mean = 68 +/- 8 ms). After ablation, one patient developed complete heart block; the remaining 15 patients developed complete right bundle branch block (RBBB) and further prolongation of the HV interval (increment = 24 +/- 16 ms). In 14 of these 15 patients, QRS duration was 138 +/- 26 ms before ablation and increased to 168 +/- 13 ms after ablation. In the remaining patient, the QRS duration was 160 ms before ablation and shortened to 144 ms following ablation despite further HV prolongation. Larger increases of HV interval after ablation were associated with smaller or negative changes in QRS duration (r = -0.77). Three was a direct relationship between QRS duration at baseline and the increment in HV interval after ablation (r = 0.70), and an inverse relationship between QRS duration before and after ablation (r = 0.84). Radiofrequency ablation of right bundle may be associated with an increase in HV interval and QRS duration. However, HV interval prolongation is not necessarily associated with QRS duration widening. A large change in HV interval is more likely to be associated with an already prolonged QRS duration before ablation and a lesser increase or even decrease in QRS duration after ablation. A shorter QRS duration before ablation is associated with a smaller HV interval increase following ablation but a greater increment in QRS duration. These findings are consistent with the concept that narrowness of QRS duration is due to synchronized activation of ventricular endocardium; whereas, QRS duration widening seen with His-Purkinje damage is due to reduced synchronization of endocardial activation.     

Flow cytometry in cervical adenocarcinoma. Correlating DNA content analysis with the clinical picture

A case is presented in which prolonged resuscitation and rewarming was performed following post-rescue cardiopulmonary arrest in severe immersion hypothermia. The rescue and resuscitation techniques necessary to optimise outcome in such cases are described.     

Effective sunscreen ingredients and cutaneous irritation in patients with rosacea

Hypothermia is a potentially life-threatening emergency. This article examines the case of a 34-year-old, mentally retarded man who experienced three episodes of hypothermia during recurrent exposure to pipamperone. After the pipamperone dose was largely reduced, no further hypothermic episodes occurred. Nine other cases of hypothermia with neuroleptic treatment were reported to the German Federal Institute of Drugs and Medical Devices from 1988 to 1997. A review of the cases revealed that nine of ten patients were treated with drugs that are potent antagonists of 5-HT2 receptors. In conjunction with experimental data, this suggests that antipsychotics with a strong 5-HT2 antagonistic component might be associated with hypothermia. Most of the newly developed "atypical" neuroleptic drugs belong to this group. Therefore, special attention for hypothermia is warranted during the use of "atypical" neuroleptics.     

Changes in perfusion and blood flow distribution following normo- and hypothermic ischemia of the kidneys

Experimental examinations were performed in 22 dogs to find out the mechanism which leads to a permanent or a reversible damage of the renal parenchyma after normo- and hypothermic ischemia. For this reason the perfusion and the distribution were examined with 133Xe, the vascular changes by angiography, and the parenchymal function with 131I-Hippuran. After normothermic ischemia a short-term reactive hyperemia appeared, which however could not compensate the damage of the renal tubular cells and the resulting excretory insufficiency. After hypothermic ischemia the perfusion was reduced, probably as a consequence of a vasconstriction by cold, however, the function of the tubular cells remained intact, because of the protective mechanism of the hypothermia. The importance of these findings for the development of the so-called "shock-kidney" (acute tubular necrosis) and for the conservative renal surgery in hypothermia is discussed and the application of measures beneficial to perfusion, are suggested.     

The impact of hypothermia on dilutional coagulopathy

The control of hemorrhage in hypothermic patients with platelet and clotting factor depletion is often impossible. Determining the cause of coagulopathic bleeding (CB) will enable physicians to appropriately focus on rewarming, clotting factor repletion, or both. Objective: To determine the contribution of hypothermia in producing CB and ascertain if simultaneous hypothermia and dilutional coagulopathy (DC) interact synergistically. Method: Prothrombin time, partial thromboplastin time, and platelet function were determined at assay temperatures of 29 degrees to 37 degrees C on normal and critically ill, noncoagulopathic (NC) individuals. Dilutional coagulopathy was created using buffered saline and the assays repeated. Results: Hypothermic assay at < or = 35 degrees C significantly prolonged coagulation times. The effect of hypothermia on NC and DC samples was not different. Conclusion: Assays performed at 37 degrees C underestimate coagulopathy in hypothermic patients. The effect of hypothermia on NC and DC is not different, indicating the lack of a synergistic effect. Normalization of clotting requires both rewarming and clotting factor repletion.     

Bisexuality in homosexual pedophilia

During the 9-year period from 1967 through 1975, 124 open-heart operations were performed on infants less than 1 year of age with 35 operative deaths (28%). Ninety-seven of these procedures used continuous cardiopulmonary bypass with normothermia or mild hypothermia, and 27 were done under deep hypothermia and circulatory arrest. Mortality and morbidity were similar regardless of the operative technique, although deep hypothermia facilitated the repair of complex lesions. The highest mortality occurred in infants less than 3 months of age. Respiratory insufficiency, usually requiring prolonged ventilatory support, occurred only among infants who had pulmonary overcirculation or congestion prior to operation. Adequacy of intraoperative repair and postoperative care were the major determinants of survival.     

The effect of raised hydrostatic pressure on heart rate variability during breath holding in man

Changes in cardiac interval (difference between two consecutive R waves of the ECG) during an expiratory breath hold (16 s) were examined in four divers during a saturation dive to 450 msw (metres of seawater). At 450 msw, breath hold caused a progressive shortening of cardiac interval that was significantly different from the changes seen at surface. The cause and significance of this shortening is unknown, but it might serve to maintain normal cardiovascular dynamics under hyperbaric conditions.     

Gain-induced oscillations in blood pressure

"Mayer waves" are long-period (6 to 12 seconds) oscillations in arterial blood pressure, which have been observed and studied for more than 100 years in the cardiovascular system of humans and other mammals. A mathematical model of the human cardiovascular system is presented, incorporating parameters relevant to the onset of Mayer waves. The model is analyzed using methods of Liapunov stability and Hopf bifurcation theory. The analysis shows that increase in the gain of the baroreflex feedback loop controlling venous volume may lead to the onset of oscillations, while changes in the other parameters considered do not affect stability of the equilibrium state. The results agree with clinical observations of Mayer waves in human subjects, both in the period of the oscillations and in the observed age-dependence of Mayer waves. This leads to a proposed explanation of their occurrence, namely that Mayer waves are a gain-induced oscillation.     

Propagated and nonpropagated calcium transients during egg activation in the annelid, Chaetopterus

Transient waves of Ca2+ release cross-fertilizing deuterostome eggs from the point of sperm entry to its antipode and provide much of the activating stimulus for the egg. Based on several indirect lines of experimental evidence, it was proposed that protostome eggs are activated by a prolonged uptake of Ca2+ from the medium due to sperm-induced membrane depolarization and that this uptake then starts an activation wave similar to those in deuterostomes, except that it moves inward from the whole surface rather than through the egg from pole to pole. To test these hypotheses, we microinjected oocytes of the polychaete annelid, Chaetopterus pergamentaceus, with semisynthetic recombinant aequorins and measured light emission in response to both fertilization and artificial activation by excess K+. Both fertilization and K(+)-activation induced multiple, brief Ca2+ transients in the eggs. The first transient did not propagate, but it was followed by a series of globally propagated Ca2+ waves interspersed with additional nonpropagated pulses. The waves traversed the egg at about 30 micrometer/sec. Sequential propagated waves and nonpropagated pulses generally originated at different regions of the egg surface, except the last few, which originated in the same "pacemaker" region. These new data are consistent with the hypothesis that the activation of protostome eggs is initiated by Ca2+ waves. However, the fact that these waves propagated from pole to pole like those in deuterostome eggs refutes the notion that Ca2+ waves in activating protostome eggs move inward from the whole surface.     

Extracorporeal circulation for warming in severe accidental hypothermia. 3 cases

BACKGROUND: Severe accidental hypothermia with central temperature below 28 degrees C can result from prolonged cold exposure and lead to a fatal outcome by spontaneous or provoked ventricular fibrillation. CASE REPORT: Three patients were referred for central temperature below 24 degrees C. At admission, the patients had major ventricular rythm disorders (two were in a state of circulatory arrest and the third had auricular fibrillation and circulatory collapse). Emergency care associated internal warning using extracorporeal circulation via the femoro-femoral route with a centrifuge pump. Outcome was favorable in 2 cases. DISCUSSION: Prognosis is very poor in patients who experience severe accidental hypothermia (< 28 degrees C) with circulatory collapse. Death often results from major rhythm disorders. Optimal emergency rewarming and oxygenation using extracorporeal circulatory assistance can be successful.     

Use and effectiveness of hypothermia blankets for febrile patients in the intensive care unit

We performed a prospective observational (noninterventional) study of hypothermia blanket use in a population of adult intensive care unit patients with body temperatures of > or = 102.5 degrees F. Thirty-nine of ninety-four febrile episodes (in 83 patients) were treated with hypothermia blankets. Logistic regression revealed that the strongest independent predictors of hypothermia blanket use were a temperature of > or = 103.5 degrees F (odds ratio [OR] = 17), mechanical ventilation (OR = 25), and acute central nervous system illness (OR = 7.5). Hospitalization in the medical intensive care unit was strongly associated with avoidance of this therapy (OR = 0.023). Treatment with a hypothermia blanket was ordered by a physician in only 15% of cases. The mean cooling rate was the same (0.028 degree F/h) for blanket-treated and control patients. Multivariate Cox regression and factorial and repeated measures of analysis of variance revealed that blanket treatment was not more effective than other cooling methods. However, this treatment was associated with more "zigzag" temperature fluctuations of > or = 3 degrees F (56% of blanket-treated patients vs. 18% of control patients; P < .001) and rebound hypothermia (18% vs. 0; P = .001). Hypothermia blanket therapy is primarily a nursing decision. We conclude that in addition to being no more effective than other cooling measures, hypothermia blanket therapy was associated with more temperature fluctuations and with more episodes of rebound hypothermia.     

Mild hypothermia after cardiac arrest in dogs does not affect postarrest cerebral oxygen uptake/delivery mismatching

PURPOSE: To compare measurements of cerebral arteriovenous oxygen content differences (oxygen extraction ratios, oxygen utilization coefficients) in dogs after cardiac arrest, resuscitated under normothermia vs. mild hypothermia for 1-2 h or 12 h. METHODS: In 20 dogs, we used our model of ventricular fibrillation (no blood flow) of 12.5 min, reperfusion with brief cardiopulmonary bypass, and controlled ventilation, normotension, normoxemia, and mild hypocapnia to 24 h. We compared a normothermic control Group I (37.5 degrees C) (n = 8); with brief mild hypothermia in Group II (core and tympanic membrane temperature about 34 degrees C during the first hour after arrest) (n = 6); and with prolonged mild hypothermia in Group III (34 degrees C during the first 12 h after arrest) (n = 6). RESULTS: In Group I, the cerebral arteriovenous O2 content difference was 5.6 +/- 1.6 ml/dl before arrest; was low during reperfusion (transient hyperemia) and increased (worsened) significantly to 8.8 +/- 2.8 ml/dl at 1 h, remained increased until 18 h, and returned to baseline levels at 24 h after reperfusion. These values were not significantly different in hypothermic Groups II and III. The cerebral venous (saggital sinus) PO2 (PssO2) was about 40 mmHg (range 29-53) in all three groups before arrest and decreased significantly below baseline values, between 1 h and 18 h after arrest; the lowest mean values were 19 +/- 19 mmHg in Group I, 15 +/- 8 in Group II (NS), and 21 +/- 3 in Group III (NS). Postarrest PssO2 values of < or = 20 mmHg were found in 6/8 dogs in Group I, 5/6 in Group II and 4/6 in Group III. Among the 120 values of PssO2 measured between 1 h and 18 h after arrest, 32 were below the critical value of 20 mmHg. CONCLUSIONS: After prolonged cardiac arrest, critically low cerebral venous O2 values suggest inadequate cerebral O2 delivery. Brief or prolonged mild hypothermia after arrest does not mitigate the postarrest cerebral O2 uptake/delivery mismatching.