Biomedical subjects

A Kurz

Publications and source records attributed to A Kurz.

At least 127 records · Page 7Linked to original sources

PubMed1996

Cerebrospinal protein tau is elevated in early Alzheimer's disease.

Protein tau concentration was determined by an enzyme linked immunoassay (ELISA) in cerebrospinal fluid (CSF) of 22 patients with clinically diagnosed Alzheimer's disease (AD), in three patients with dementia caused by other neurological disorders (OND) and in 19 cognitively healthy controls. A significantly elevated protein tau concentration was found in AD patients as compared with controls, even in 11 patients with very mild dementia. There was no correlation between protein tau and the severity of cognitive impairment as assessed with the Mini Mental State Examination (MMSE). Tau concentrations were not or only slightly elevated in OND. We conclude that protein tau in CSF might be helpful as a biological marker for the early diagnosis of AD.

Aged↗

PubMed1996

Perioperative normothermia to reduce the incidence of surgical-wound infection and shorten hospitalization. Study of Wound Infection and Temperature Group.

BACKGROUND: Mild perioperative hypothermia, which is common during major surgery, may promote surgical-wound infection by triggering thermoregulatory vasoconstriction, which decreases subcutaneous oxygen tension. Reduced levels of oxygen in tissue impair oxidative killing by neutrophils and decrease the strength of the healing wound by reducing the deposition of collagen. Hypothermia also directly impairs immune function. We tested the hypothesis that hypothermia both increases susceptibility to surgical-wound infection and lengthens hospitalization. METHODS: Two hundred patients undergoing colorectal surgery were randomly assigned to routine intraoperative thermal care (the hypothermia group) or additional warming (the normothermia group). The patient's anesthetic care was standardized, and they were all given cefamandole and metronidazole. In a double-blind protocol, their wounds were evaluated daily until discharge from the hospital and in the clinic after two weeks; wounds containing culture-positive pus were considered infected. The patients' surgeons remained unaware of the patients' group assignments. RESULTS: The mean (+/- SD) final intraoperative core temperature was 34.7 +/- 0.6 degrees C in the hypothermia group and 36.6 +/- 0.5 degrees C in the normothermia group (P < 0.001) Surgical-wound infections were found in 18 of 96 patients assigned to hypothermia (19 percent) but in only 6 of 104 patients assigned to normothermia (6 percent, P = 0.009). The sutures were removed one day later in the patients assigned to hypothermia than in those assigned to normothermia (P = 0.002), and the duration of hospitalization was prolonged by 2.6 days (approximately 20 percent) in hypothermia group (P = 0.01). CONCLUSIONS: Hypothermia itself may delay healing and predispose patients to wound infections. Maintaining normothermia intraoperatively is likely to decrease the incidence of infectious complications in patients undergoing colorectal resection and to shorten their hospitalizations.

Adult↗

PubMed1996

[Prognostic aspects of panic disorder].

Panic disorder is considered as a qualitatively distinct form among the anxiety disorders. Follow-up studies have demonstrated that the course of panic disorder may be chronic. Only one out of ten patients remains completely free of symptoms within an observational period of 3 to 7 years. The majority of patients suffer long-standing anxiety symptoms which do not significantly interfere with working performance or social relationships. Another ten percent of the patients are continuously impaired in everyday living by severe symptoms. Long duration and severe degree of symptoms at the initial assessment, as well as coexistent depression are associated with a poor outcome. There is evidence of an increased mortality in patients with panic disorder. Suicides are overrepresented among the causes of death. It is not clear whether this is due to the frequent comorbidity between panic disorder, major depression, and substance abuse.

Activities of Daily Living↗

PubMed1996

Mild hypothermia increases blood loss and transfusion requirements during total hip arthroplasty.

BACKGROUND: In-vitro studies indicate that platelet function and the coagulation cascade are impaired by hypothermia. However, the extent to which perioperative hypothermia influences bleeding during surgery remains unknown. Accordingly, we tested the hypothesis that mild hypothermia increases blood loss and allogeneic transfusion requirements during hip arthroplasty. METHODS: Blood loss and transfusion requirements were evaluated in 60 patients undergoing primary, unilateral total hip arthroplasties who were randomly assigned to normothermia (final intraoperative core temperature 36.6 [0.4] degrees C) or mild hypothermia (35.0 [0.5] degrees C). Crystalloid, colloid, scavenged red cells, and allogeneic blood were administered by strict protocol. FINDINGS: Intra- and postoperative blood loss was significantly greater in the hypothermic patients: 2.2 (0.5) L vs 1.7 (0.3) L, p < 0.001). Eight units of allogeneic packed red cells were required in seven of the 30 hypothermic patients, whereas only one normothermic patient required a unit of allogeneic blood (p < 0.05 for administered volume). A typical decrease in core temperature in patients undergoing hip arthroplasty will thus augment blood loss by approximately 500 mL. INTERPRETATION: The maintenance of intraoperative normothermia reduces blood loss and allogeneic blood requirements in patients undergoing total hip arthroplasty.

Adult↗

PubMed1996

Apolipoprotein E type 4 allele and Alzheimer's disease: effect on age at onset and relative risk in different age groups.

The effect of the apolipoprotein E (apoE) genotype on the age at onset of Alzheimer's disease (AD) and the relative risk conferred by the apoE epsilon 4 allele were studied in 91 patients and 69 healthy age-matched controls. According to the age of presentation, which varied from 44 to 95 years, subjects were divided into four groups. The inheritance of at least one epsilon 4 allele was associated with a significant reduction of the age at onset by 7.7 years among patients who were 83 years or older when examined. A weaker inverse relationship between the epsilon 4 allele and the age at onset was also observed among patients who were aged 44-63 years at presentation. The effect of the epsilon 4 allele was minimal or absent in the two intermediate age categories. The relative risk of AD conferred by the inheritance of at least one epsilon 4 allele showed no consistent age-related pattern. The overall risk expressed as an odds ratio was 5.0 (95% CI 2.4-10.5). With respect to the limitations of the study, we tentatively conclude (1) that the effect of the apoE epsilon 4 allele on the age at onset is not restricted to AD patients of a particular age, in accordance with current hypotheses on the role of apoE gene products in the biology of AD; (2) that the relative risk of AD associated with the epsilon 4 allele is not significantly modulated by age. Although the apoE epsilon 4 allele is an important susceptibility factor for AD occurring in middle age as well as in later life, it is of limited value in routine clinical diagnosis and should not be used for predictive testing in asymptomatic individuals.

Age Factors↗

PubMed1996

Active and inactive genes localize preferentially in the periphery of chromosome territories.

The intranuclear position of a set of genes was analyzed with respect to the territories occupied by the whole chromosomes in which these genes are localized. Genes and their respective chromosome territories were simultaneously visualized in three-dimensionally preserved nuclei applying dual color fluorescence in situ hybridization. Three coding (DMD, MYH7, and HBB) and two noncoding sequences (D1Z2 and an anonymous sequence) were analyzed in four different cell types, including cells where DMD and MYH7 are actively transcribed. Spatial analysis by confocal laser scanning microscopy revealed that the genes are preferentially located in the periphery of chromosome territories. This positioning was independent from the activity of the genes. In contrast, the non-expressed anonymous fragment was found randomly distributed or localized preferentially in the interior of the corresponding chromosome territory. Furthermore, the distribution of the analyzed genes within the territorial peripheries was found to be highly characteristic for each gene, and, again, independent from its expression. The impact of these findings with regard to the three-dimensional arrangement of the linear DNA string within chromosome territories, as well as with respect to a putative nuclear subcompartment confining gene expression, are discussed.

Cells, Cultured↗

PubMed1996

Mild intraoperative hypothermia reduces production of reactive oxygen intermediates by polymorphonuclear leukocytes.

Mild hypothermia directly impairs numerous immune functions in vitro. However, the in vivo effects of mild hypothermia on neutrophil phagocytosis and oxidative killing remain unknown. We tested the hypothesis that mild intraoperative hypothermia decreases neutrophil phagocytic capacity and generation of reactive oxygen intermediates (a measure of oxidative killing). Additionally, we evaluated the effects of in vitro temperature manipulations on each function. Thermal management was randomly assigned in 10 surgical patients, causing intraoperative core temperatures to range from 33 to 37 degrees C. Production of reactive oxygen intermediates and neutrophil phagocytosis were evaluated using flow cytometry at ambient temperature. Phagocytic capacity was assessed by uptake of fluorescein isothiocyanate-labeled Escherichia coli. Reactive oxygen production was estimated by the intracellular conversion of dihydrorhodamine 123 to rhodamine 123. Blood samples were obtained preoperatively, 1 h after surgery started, and 2 h postoperatively. Blood was also obtained from 10 matched control subjects and tested at 32, 37, and 40 degrees C. Neutrophil oxidative and phagocytic capacities were significantly reduced intraoperatively, compared with preoperative and postoperative values. Intraoperative production of reactive oxygen species was linearly related to core temperature. In contrast, there was no correlation between core temperature and phagocytic activity. In vitro production of reactive oxygen intermediates increased sixfold from 32 to 40 degrees C. In vitro phagocytic capacity increased fourfold in this temperature range. Production of oxidative intermediates was most closely related to intraoperative core temperature, decreasing nearly fourfold over a 4 degree C range. This in vitro temperature dependence was matched in vitro. Impaired neutrophil oxidative killing may contribute to the observed hypothermia-induced reduction in resistance to infection.

Acute-Phase Proteins↗

PubMed1996

Isoflurane produces marked and nonlinear decreases in the vasoconstriction and shivering thresholds.

BACKGROUND: Desflurane decreases the vasoconstriction and shivering thresholds disproportionately at high anesthetic concentrations. This result contrasts with the authors' previous report that isoflurane decreases the vasoconstriction threshold linearly. It is surprising that the basic shape of the concentration-response curve should differ with these two otherwise similar anesthetics. Therefore, the hypothesis that isoflurane produces a nonlinear reduction in the vasoconstriction threshold was tested. Because the effect of isoflurane on shivering remains unknown, the extent to which isoflurane reduces the shivering threshold also was determined. METHODS: Eight men volunteered to be studied on four randomly ordered days: (1) a target end-tidal isoflurane concentration of 0.55%, (2) a target concentration of 0.7%, (3) control (no anesthesia) and a target end-tidal concentration of 0.85%, and (4) a target end-tidal concentration of 1.0%. Volunteers were surface-cooled until peripheral vasoconstriction and shivering were observed. We arithmetically compensated for changes in skin temperature using the established linear cutaneous contributions to control for each response. From the calculated thresholds (core temperatures triggering responses at a designated skin temperature of 34 degrees C), the concentration-response relation was determined. RESULTS: Isoflurane administration produced a dose-dependent reduction in the vasoconstriction and shivering thresholds, decreasing each approximately 4.6 degrees C at an end-tidal concentration of 1%. Residual analysis indicated that the vasoconstriction and shivering thresholds were decreased in a nonlinear fashion during isoflurane administration. The vasoconstriction-to-shivering range was 1.5 +/- 0.8 degree C without isoflurane, and did not change significantly during isoflurane administration. CONCLUSIONS: The vasoconstriction-to-shivering range remained unchanged by isoflurane administration. In this regard, the effects of isoflurane are similar to those of desflurane, propofol, and alfentanil. The current data differ from the authors' previous report, in that the dose-dependence for vasoconstriction was nonlinear, with isoflurane reducing the threshold disproportionately at higher anesthetic concentrations. Differing dose-dependence in the two studies may result either because the current study's volunteers were not exposed to surgical stimulation and were given less isoflurane, or because of design limitations in the previous protocol.

Adult↗

PubMed1996

Thermoregulatory vasoconstriction does not impede core warming during cutaneous heating.

BACKGROUND: Although forced-air warming rapidly increases intraoperative core temperatures, it is reportedly ineffective postoperatively. A major difference between these two periods is that arteriovenous shunts are usually dilated during surgery, whereas vasoconstriction is uniform in hypothermic postoperative patients. Vasoconstriction may decrease efficacy of warming because its major physiologic purposes are to reduce cutaneous heat transfer and restrict heat transfer between the two thermal compartments. Accordingly, we tested the hypothesis that thermoregulatory vasoconstriction decreases cutaneous transfer of applied heat and restricts peripheral-to-core flow of heat, thereby delaying and reducing the increase in core temperature. METHODS: Eight healthy male volunteers anesthetized with propofol and isoflurane were studied. Volunteers were allowed to cool passively until core temperature reached 33 degrees C. On one randomly assigned day, the isoflurane concentration was reduced, to provoke thermoregulatory arteriovenous shunt vasoconstriction; on the other study day, a sufficient amount of isoflurane was administered to prevent vasoconstriction. On each day, forced-air warming was then applied for 2 h. Peripheral (arm and leg) tissue heat contents were determined from 19 intramuscular needle thermocouples, 10 skin temperatures, and "deep" foot temperature. Core (trunk and head) heat content was determined from core temperature, assuming a uniform compartmental distribution. Time-dependent changes in peripheral and core tissue heat contents were evaluated using linear regression. Differences between the vasoconstriction and vasodilation study days, and between the peripheral and core compartments, were evaluated using two-tailed, paired t tests. Data are presented as means +/-SD; P < 0.01 was considered statistically significant. RESULTS: Cutaneous heat transfer was similar during vasoconstriction and vasodilation. Forced-air warming increased peripheral tissue heat content comparably when the volunteers were vasodilated and vasoconstricted: 48 +/- 7 versus 53 +/- 10 kcal/h. Core compartment tissue heat content increased similarly when the volunteers were vasodilated and vasoconstricted: 51 +/- 8 versus 44 +/- 11 kcal/h. Combining the two study days, the increase in peripheral and core heat contents did not differ significantly: 51 +/- 8 versus 48 +/- 10 kcal/h, respectively. Core temperature increased at essentially the same rate when the volunteers remained vasodilated (1.3 degrees C/h) as when they were vasoconstricted (1.2 degrees C/h). CONCLUSIONS: The authors failed to confirm their hypothesis that thermoregulatory vasoconstriction decreases cutaneous transfer of applied heat and restricts peripheral-to-core flow of heat in anesthetized subjects. The reported difference between intraoperative and postoperative rewarming efficacy may result from nonthermoregulatory anesthetic-induced vasodilation.

Adult↗

PubMed1996

Risk of dementia among relatives of Alzheimer's disease patients in the MIRAGE study: What is in store for the oldest old?

Despite recent advances in the molecular genetics of Alzheimer's disease (AD), several fundamental questions concerning risk of illness are unresolved, namely, if Mendelian factors account for the incidence of the disease, and if AD is an inevitable consequence of the aging process. This study was designed to address these issues and other aspects of familial aggregation of the disorder. A consecutive sample of 1,694 patients who met criteria for a diagnosis of probable or definite AD were ascertained in 13 centers participating in the Multi-Institutional Research in Alzheimer Genetic Epidemiology (MIRAGE) project. Lifetime risk and age at onset of AD among various strata of 12,971 first-degree relatives was estimated using survival analysis procedures. The lifetime risk of AD in first-degree relatives was 39.0% +/- 2.1% by age 96 years. Age-specific risk of AD declined after age 90 and the data set included 61 apparently unaffected persons who survived to age 96 without becoming demented. Female relatives had a higher risk of AD than male relatives at all ages. By age 80, children of conjugal AD couples had a cumulative risk of 54%, 1.5 times greater than the sum of the risks to children having affected mothers or fathers, and nearly 5 times greater than the risk to children having normal parents. Children of affected fathers had a cumulative risk that was 1.4 times the corresponding risk to children of affected mothers. Risk assessment in early-onset and late-onset families, using various strategies for determining the age cut-off, yielded contradictory results. These data suggest the following: (1) the lifetime risk among relatives does not support a simple autosomal dominant inheritance pattern of disease; (2) women are innately more susceptible to AD than men; (3) the proportion of hereditary cases may be higher in men than women; (4) distinction between early- onset and late-onset forms of AD has little meaning in the absence of a biological marker; (5) the risk of AD decreases after age 90; and (6) AD therefore may not be an inevitable concomitant of the aging process, a conclusion that has profound implications for basic and applied AD research. The age- and sex-specific lifetime risks derived from this study are sufficiently robust to be a reliable source of information for counseling relatives of AD patients.

Age Factors↗

PubMed1996

Apolipoprotein E epsilon 4 allele, cognitive decline, and deterioration of everyday performance in Alzheimer's disease.

Many studies have demonstrated an association between the apolipoprotein E (apoE) epsilon 4 allele and Alzheimer's disease (AD). The present study is concerned with the relationship between the apoE epsilon 4 allele and the progression of symptoms in AD. We determined rates of cognitive decline and deterioration in everyday performance prospectively over 3 years in 64 patients with clinically diagnosed AD using the Cambridge Cognitive Examination (CAMCOG), the Mini-Mental State Examination (MMSE), and the Dementia Scale (DS) included in the Cambridge Mental Disorders of the Elderly Examination (CAMDEX). Carriers and noncarriers of the epsilon 4 allele did not significantly differ in cognitive functioning and everyday performance at baseline measurements. The time that had elapsed since the estimated onset of symptoms was also not different between the two groups. This suggested that the clinical progression of AD was not associated with the epsilon 4 status before the patients entered the study. On prospective observation, the rate of cognitive decline assessed with the CAMCOG and the MMSE and the rate of deterioration in everyday performance rated with the DS were also not different between carriers and noncarriers of the epsilon 4 allele. We conclude that the clinical course of AD is independent of the apoE epsilon 4 allele.

Age of Onset↗

PubMed1996

Lack of association between alpha 1-antichymotrypsin polymorphism, Alzheimer's disease, and allele epsilon 4 of apolipoprotein E.

We investigated the possibility that a polymorphism of alpha 1-antichymotrypsin modifies the risk for Alzheimer's disease (AD). Testing 147 AD patients and 74 controls, we did not find evidence of an association between alpha 1-antichymotrypsin polymorphism and AD and also failed to detect a modifying effect of this polymorphism in patients carrying at least one epsilon 4 allele of apolipoprotein E.

Alleles↗

PubMed1996

Evidence for major gene inheritance of Alzheimer disease in families of patients with and without apolipoprotein E epsilon 4.

Apolipoprotein E (APOE) genotype is the single most important determinant to the common form of Alzheimer disease (AD) yet identified. Several studies show that family history of AD is not entirely accounted for by APOE genotype. Also, there is evidence for an interaction between APOE genotype and gender. We carried out a complex segregation analysis in 636 nuclear families of consecutively ascertained and rigorously diagnosed probands in the Multi-Institutional Research in Alzheimer Genetic Epidemiology study in order to derive models of disease transmission which account for the influences of APOE genotype of the proband and gender. In the total group of families, models postulating sporadic occurrence, no major gene effect, random environmental transmission, and Mendelian inheritance were rejected. Transmission of AD in families of probands with at least one epsilon 4 allele best fit a dominant model. Moreover, single gene inheritance best explained clustering of the disorder in families of probands lacking epsilon 4, but a more complex genetic model or multiple genetic models may ultimately account for risk in this group of families. Our results also suggest that susceptibility to AD differs between men and women regardless of the proband's APOE status. Assuming a dominant model, AD appears to be completely penetrant in women, whereas only 62%-65% of men with predisposing genotypes develop AD. However, parameter estimates from the arbitrary major gene model suggests that AD is expressed dominantly in women and additively in men. These observations, taken together with epidemiologic data, are consistent with the hypothesis of an interaction between genes and other biological factors affecting disease susceptibility.

Adult↗

PubMed1996

Thermoregulatory vasoconstriction and perianesthetic heat transfer.

Heat transfer between the core and its environment in normothermic and slightly hypothermic situations is determined largely by the influence of vasomotion on convection. Tonic vasoconstriction, the normal barrier to heat loss from the core, is impaired upon induction of anesthesia. The resulting dilation of the arteriovenous shunts leads to redistribution of heat from the core to the periphery, diminishing the temperature gradient between the two compartments. With reemergence of thermoregulatory vasoconstriction at core temperatures near 34 degrees C, the core and the periphery are again separated, with metabolic heat being largely constrained to the core. Under normal conditions of mild thermal stress, thermoregulatory vasoconstriction is thus able to protect core temperature by reducing cutaneous heat transfer and functionally isolating the peripheral and core thermal compartments. Consequently, anesthetic-induced alterations in vasomotor tone is one of the major factors influencing core temperature in patients who are not actively cooled or warmed. In contrast, thermoregulatory tone is insufficient to prevent core temperature perturbations in patients undergoing vigorous cutaneous cooling or warming.

Anesthesia, General↗

PubMed1996

Thermoregulation and hyperthermia.

Despite minor daily and monthly cyclical variations, body temperature remains relatively constant. Core temperature is maintained by thermoregulatory responses such as sweating, vasoconstriction and shivering, which are largely controlled by the hypothalamus. Within the hierarchy of neural structures regulating autonomic thermoregulatory responses, the preoptic area of the anterior hypothalamus plays a dominant role. In contrast, the posterior hypothalamus mediates behavioral defenses. Neurons in both regions sense core temperature and integrate central and peripheral thermal information. The setpoint temperature is then determined by relative synaptic inputs to warm-sensitive, cold-sensitive, and temperature-insensitive neurons. Fever is a regulated elevation in the preoptic setpoint temperature. Endogenous pyrogens and other fever mediators inhibit preoptic warm-sensitive neurons that normally facilitate heat loss and suppress heat production. This elevates the setpoint temperature for all thermoregulatory responses and activates cold-defenses such as vasoconstriction (which decreases heat loss) and shivering (which increases metabolic heat production). When pyrogen concentrations decrease, the setpoint temperature returns towards normal, triggering active vasodilation and sweating, which increases heat loss from the skin surface. The increasing phase of fever is often associated with shivering, which can markedly increase heart rate and cardiac output. Defervescence (and passive hyperthermia) is also often accompanied by tachycardia resulting from active precapillary vasodilation. Thus, cardiovascular complications are common throughout the febrile course and constitute the major clinical consequence of fever.

Body Temperature↗

PubMed1995

Apolipoprotein E genotype in patients with Alzheimer's disease: implications for the risk of dementia among relatives.

Numerous studies have shown that the risk of Alzheimer's disease (AD) is associated with the dose of the epsilon 4 allele of apolipoprotein E (ApoE). However, more than one third of AD patients lack epsilon 4 and many persons having epsilon 4 survive cognitively intact to old age. We evaluated the lifetime risk of disease in 3,999 first-degree relatives of 549 probands who met the criteria for probable or definite AD and whose ApoE genotypes were known. ApoE genotypes for relatives were not determined. After age 65 the risk among relatives was proportional, as much as 7 to 10% at age 85, to the number of epsilon 4 alleles present in the proband. Risks to relatives of ApoE 2/2 and 2/3 probands were nearly identical at all ages to risks for relatives of ApoE 3/3 probands. The expected proportion of relatives having at least one epsilon 4 allele was calculated for each genotype group based on the distribution of parents, sibs, and offspring in the sample. Among relatives in the ApoE 3/3 group, the lifetime risk for AD by age 90 was three times greater than the expected proportion of epsilon 4 carriers, suggesting that factors other than ApoE contribute to AD susceptibility. Furthermore, the 44% risk of AD by age 93 among relatives of ApoE 4/4 probands indicates that as many as 50% of people having at least one epsilon 4 allele do not develop AD. We also found that among male relatives, risk of AD in the ApoE 3/4 group was similar to that for the ApoE 3/3 group but significantly less than the risk for the ApoE 4/4 group. In contrast, among female relatives the risk for the ApoE 3/4 group was nearly twice that for the ApoE 3/3 group and identical to the risk for the ApoE 4/4 group. These findings are consistent with a sex-modification effect of the E4 isoform on disease susceptibility.

Age of Onset↗

PubMed1995

Postoperative hemodynamic and thermoregulatory consequences of intraoperative core hypothermia.

STUDY OBJECTIVE: To evaluate the postoperative hemodynamic and thermoregulatory consequences of intraoperative core hypothermia. DESIGN: Prospective, randomized clinical trial. SETTING: Operating room and postanesthesia care unit of a university hospital. PATIENTS: 74 healthy, ASA status I, II, and III patients (average age 58 yrs) undergoing elective colon surgery. INTERVENTIONS: Patients were randomly assigned to be kept normothermic or approximately 2.5 degrees C hypothermic during surgery. Anesthesia was maintained with isoflurane, nitrous oxide, and fentanyl. Postoperatively, surgical pain was treated with patient-controlled analgesia (PCA) opioid. MEASUREMENTS AND MAIN RESULTS: An observer blinded to group assignment and core temperatures evaluated shivering, thermal comfort, surgical pain, heart rates (HRs), and blood pressures (BPs) during the first six postoperative hours. Morphometric characteristics, oxygen saturation, fluid balance, PCA-administered opioid, and visual analog pain scores were comparable in the two groups. Hypothermic patients felt uncomfortably cold during recovery, and their postoperative core temperatures remained significantly less than in the normothermic patients for more than four hours. Peripheral vasoconstriction and shivering were common in the hypothermic patients but rare in those kept normothermic. HRs and BPs were comparable in the two groups. CONCLUSIONS: These data confirm that the effects of intraoperative hypothermia on postoperative HR and BP are modest in relatively young, generally healthy patients. In contrast, intraoperative hypothermia caused substantial postoperative thermal discomfort, and full recovery from hypothermia required many hours. Delayed return to care normothermia apparently resulted largely from postoperative thermoregulatory impairment.

Analgesia, Patient-Controlled↗

PubMed1995

Morphometric influences on intraoperative core temperature changes.

Intraoperative core hypothermia develops in three characteristic phases: 1) core-to-peripheral redistribution of body heat that is most prominent during the first hour after induction of anesthesia; 2) subsequent slow linear decrease in core temperature resulting largely from heat loss exceeding metabolic heat production; and 3) core temperature plateau resulting when thermoregulatory vasoconstriction decreases cutaneous heat loss and constrains metabolic heat to the core thermal compartment. Accordingly, we tested the hypotheses that: 1) core cooling does not depend on body fat (BF) or the ratio of weight-to-surface area (Wt/SA) during the initial redistribution phase; 2) the core cooling phase; 2) the core cooling rate is a function of the Wt/SA ratio during the second phase; and 3) the rate of core cooling during the plateau phase (after vasoconstriction) will be determined by the percentage of BF. In 40 patients undergoing elective colon surgery, the amount of redistribution hypothermia was inversely proportional to the percentage of BF (delta TC = 0.034.BF-2.2, r2 = 0.63) and the Wt/SA ratio (delta TC = 0.052.Wt/SA-3.35, r2 = 0.66). The core cooled linearly during the second phase, and the cooling rate was inversely proportional to the Wt/SA ratio (rate = 0.035.(Wt/SA)-2.2, r2 = 0.29). Thermoregulatory vasoconstriction was effective in virtually all patients independent of their morphology, and produced a four-fold reduction in the core cooling rate. These results indicate that patient morphometric characteristics substantially influence intraoperative core temperature changes, and that the effect depends on the hypothermia phase.

Adult↗