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At least 1,261 records · Page 70Linked to original sources
PubMed1996

Methohexital infusion technique for conscious sedation.

PURPOSE: The purpose of this study was to evaluate a methohexital infusion technique for conscious sedation in oral surgical procedures. Patients were evaluated for recall, comfort, recovery, and surgeon's estimate of cooperation. MATERIALS AND METHODS: Twenty adult (mean age, 29 years) ASA I or II patients requiring various dentoalveolar procedures were entered into the study. Administration of 1.5 micrograms/kg fentanyl and 1 mg midazolam were given until sedation was achieved. An infusion of methohexital was started using 50 micrograms/kg/min and increased as needed to 75 micrograms/kg/min. Postoperatively, visual analog scales were used to evaluate the efficacy of the technique. RESULTS: The average total amount of methohexital infused was 257 mg for an average surgical time of 88 minutes. Recovery times were short and uneventful. Patients were cleared for discharge in under 35 minutes. No cardiac or respiratory side effects were noted other than a mild increase ( < 15%) in heart rate. Shivering and hiccoughing were noted in two and four cases, respectively. Recall of surgical events reported by patients was low and patient cooperation was high as reported by surgeons. CONCLUSION: The continuous infusion of methohexital for conscious sedation has been shown to be safe, effective, inexpensive, and well accepted by patients and surgeons.

Adolescent↗
PubMed1997

The efficacy of tepid sponge bathing to reduce fever in young children.

Tepid sponge baths distress febrile children, and their efficacy at reducing fever has not been established. This study compared fever reduction and with (1) acetaminophen alone and (2) acetaminophen plus a 15-minute tepid sponge bath. Twenty children, ages 5 to 68 months, who presented to the emergency department or urgent care center with fever of > or = 38.9 degrees C were randomized to receive (1) acetaminophen alone or (2) acetaminophen plus a 15-minute tepid sponge bath. All subjects received a 15-mg/kg dose of acetaminophen. Tympanic temperature was monitored every 30 minutes for 2 hours. Subjects were monitored for signs of discomfort (crying, shivering, goosebumps). Sponge-bathed subjects cooled faster during the first hour but there was no significant temperature difference between the groups over the 2-hour study period (P = .871). Subjects in the sponge bath group had significantly higher discomfort scores (P = .009).

Acetaminophen↗
PubMed2002

[Severe hypothermia associated with cesarean section under spinal anesthesia].

Temperature monitoring and prevention of hypothermia are rarely used during spinal anaesthesia for caesarean section because hypothermia risk is considered very low. However, in same conditions, we observed two cases of severe hypothermia. We report these two cases and discuss the effects of spinal anaesthesia on thermoregulatory system. Hypothermia seems explained by the effects of perimedullar anaesthesia that decrease the shivering and the vasoconstriction thresholds. These effects are potentiated by morphinomimetic adjunction. At last, we recall prophylactics measures.

Adult↗
PubMed1990

[Value of continuous venous blood oxygen measurement during external circulatory assistance].

A case is reported of a 40 year-old man, on the waiting-list for heart transplantation, who developed terminal heart failure. Using an Opticath catheter and a radial artery catheter, SV(-)O2 was monitored continuously, and cardiac output, pulmonary arterial and wedged pressures, and right atrial pressure were repeatedly measured. Despite appropriate treatment (adrenaline, dobutamine, glyceryl trinitrate), the patient remained in anuria and cardiogenic shock. External circulatory support (ECS) (BVS 5000 Abiomed) was therefore used as a bridge to cardiac transplantation. The resultant increase in systemic blood flow led to an early and fast rise in SV(-)O2, from 40% to 73%, with a decrease in the oxygen extraction ratio (ERO2) from 50 to 30%. Serum lactate concentrations returned to normal within the first six hours of ECS (less than 120 mg.l-1). During the first 24 h of ECS, SV(-)O2 decreased and ERO2 rose significantly on two occasions: during an episode of shivering, and another of restlessness during nursing. An attempt at weaning the patient from the ventilator at the 39th h also led to a sudden decrease in SV(-)O2, with a rise in ERO2. The Opticath catheter was finally removed after 150 h of ECS because of a decrease in reflected light intensity.

Adult↗
PubMed2000

A multicenter comparison of isoflurane and propofol as adjuncts to remifentanil-based anesthesia.

STUDY OBJECTIVE: To compare recovery, hemodynamics, and side effects of remifentanil-based anesthesia with hypnotic concentrations of isoflurane or propofol. DESIGN: Multicenter, prospective, randomized, two-group study. SETTING: 15 university and 5 municipal hospitals. PATIENTS: 249 ASA physical status I, II, and III adult patients scheduled for elective gynecological laparoscopy, varicose vein, or arthroscopic surgery of at least 30 minutes' duration. INTERVENTIONS: Anesthesia was induced in the same manner in both groups: remifentanil-bolus (1 microg/kg), start of remifentanil-infusion (0. 5 microg/kg/min), followed by propofol as needed for induction. Five minutes after intubation, remifentanil was reduced to 0.25 microg/kg/min, and it was combined with either a propofol-infusion (0.1 mg/kg/min) or with isoflurane (0.6 vol% end-tidal) in O(2)/air. Adverse hemodynamic responses of heart rate and systolic blood pressure were recorded and treated according to a predefined protocol. With termination of surgery, anesthetic delivery was discontinued simultaneously without tapering, and recovery times were recorded. MEASUREMENTS AND MAIN RESULTS: No significant differences were observed between the remifentanil-isoflurane or remifentanil-propofol treatment regimens. Recovery times (means +/- SD) were similar for spontaneous ventilation (5.8 +/- 3.2 min vs. 6. 3 +/- 3.7 min), extubation (7.6 +/- 3.5 vs. 8.5 +/- 4.2 min), eye opening (6.8 +/- 3.2 vs. 7.5 +/- 3.8 min), and arrival to the postanesthesia care unit (16.5 +/- 7.0 vs.18.0 +/- 7.2 min). There were no significant differences in adverse hemodynamic responses, postoperative shivering, nausea, or vomiting between the groups. CONCLUSIONS: Emergence after remifentanil-based anesthesia with 0.6 vol% of isoflurane is at least as rapid as with 0.1 mg/kg/min propofol. Both isoflurane and propofol are suitable adjuncts to remifentanil, and the applied dosages are clinically equivalent with respect to emergence and recovery. Therefore, both combinations should be appropriate, particularly in settings in which rapid recovery from anesthesia is desirable, such as fast tracking and/or ambulatory surgery.

Adult↗
PubMed1998

Nonmalignant hyperthermia on induction of anesthesia in a pediatric patient undergoing bidirectional Glenn procedure.

We report a case of severe hyperthermia in a 6-month-old boy with a single ventricle, dextrocardia, asplenia, and transposition of the great arteries, during induction of anesthesia on three separate occasions. To our knowledge, this is the first case reported of repeated intraoperative hyperthermia not related to malignant hyperthermia, infection, neuroendocrine tumor, or iatrogenic causes (e.g., anticholinergic blockade or warming devices). The severe hyperthermia may be secondary to the medications given before and during induction and/or the stress of the induction. Among the induction medications given during the three episodes, fentanyl is the most likely contributing drug. Human data indicate that opioids increase the sweating threshold and decrease the vasoconstriction and shivering thresholds. The medications could cause a widening in the thermoregulation interthreshold and the stress could induce nonshivering thermogenesis.

Adjuvants, Anesthesia↗
PubMed1999

Effect of low-dose propofol infusion on total-body oxygen consumption after coronary artery surgery.

OBJECTIVE: To investigate the effect of low-dose propofol infusion on total-body oxygen consumption (VO2) after coronary artery bypass grafting (CABG) surgery. DESIGN: A prospective, randomized, placebo-controlled, double-blind study. SETTING: Cardiovascular intensive care unit in a university hospital. PARTICIPANTS: Thirty patients after elective, uncomplicated CABG surgery. INTERVENTION: Patients were administered a continuous infusion of propofol with a fixed rate of 1 mg/kg/h (n = 15) or placebo (n = 15) during the spontaneous rewarming period of approximately 5 hours after surgery. A light level of sedation (Ramsay sedation score > or =2) was maintained by administering small doses of diazepam, 0.1 mg/kg, as required. Morphine, 0.05 mg/kg, was administered for analgesia as required. MEASUREMENTS AND MAIN RESULTS: Total-body VO2 was measured by indirect calorimetry. In addition, shivering (on a five-grade scale), hemodynamics, and plasma catecholamine and serum cortisol concentrations were measured. Diazepam, 5.6+/-7.4 mg (mean +/- standard deviation), was administered to the patients receiving propofol, and 16.1+/-12.2 mg was administered to the patients receiving placebo (p < 0.05). There was no difference in the dose of morphine between the groups (3.2+/-3.9 v 4.2+/-5.5 mg in the propofol and placebo groups, respectively). At any time during the study, VO2 was not different between the groups. VO2 increased from 130+/-29 to 172+/-29 mL/min/m2 in the propofol group and from 118+/-24 to 167+/-27 mL/min/m2 in the placebo group. Mean arterial pressure and heart rate were lower in the propofol group (p < 0.05). Stress hormone levels did not differ between the groups. CONCLUSION: Low-dose propofol infusion and additional diazepam as required does not decrease total-body VO2 compared with a pure diazepam bolus-dose technique when administered for light sedation during the immediate recovery period after CABG surgery.

Adrenergic Agonists↗
PubMed2006

Oral misoprostol versus oxytocin in the management of the third stage of labour.

OBJECTIVE: To compare the effects of oral misoprostol 800 mug with intramuscular oxytocin 10 IU in routine management of the third stage of labour. METHODS: This randomized controlled trial was performed in a rural district hospital in Ghana, West Africa, and enrolled women in labour with anticipated vaginal delivery and no known medical contraindication to prostaglandin administration. Women were randomized to receive oral misoprostol 800 mug or intramuscular oxytocin 10 IU. Blood samples were taken to determine hemoglobin concentration before delivery and at 12 hours post partum. Treatment was administered at delivery of the anterior shoulder. The primary outcome was the change in hemoglobin concentration from before to after delivery. Secondary outcomes included other measures of blood loss and presumed medication side effects. RESULTS: In total, 450 women were enrolled in the study. Their baseline characteristics were similar. There was no significant difference between the groups in the change in hemoglobin concentration (misoprostol 1.07 g/dL and oxytocin 1.00 g/dL). The only significant secondary outcomes were shivering (80.7% with misoprostol vs. 3.6% with oxytocin) and pyrexia (11.4% with misoprostol, none with oxytocin). CONCLUSION: Routine use of oral misoprostol 800 microg appears to be as effective as 10 IU parenteral oxytocin in minimizing blood loss during the third stage of labour, as determined by change in hemoglobin concentration. Misoprostol appears to be a safe, inexpensive, and effective uterotonic for use in rural and remote areas, where intravenous oxytocin may be unavailable.

Administration, Oral↗
PubMed1999

Influence of platelet activating factor on gastrointestinal electrical activity and some haematological and clinical parameters in the conscious miniature pig.

The effects of intravenous (i.v.) infusion of platelet-activating factor (PAF), 100 ng/kg/min for 10 min, with and without pretreatment with a selective PAF-antagonist on gastrointestinal electrical activity, arterial pressure and clinical and haematological parameters were studied. Conscious miniature pigs with electrodes implanted in the wall of the antrum pylori and small and large intestine were used. Platelet-activating factor induced restlessness or depression, shivering, tachypnoea and coughing, retching and vomiting, hypotension and a delayed and sustained increase in leucocyte count with an increase in percentage of segmented neutrophils. The PAF-antagonist, SAH 63-675, administered at 10 mg/kg intravenously, inhibited these effects. Platelet-activating factor resulted in a decrease in electrical activity in the antrum and large intestine, whereas small intestinal activity was not significantly influenced. Pretreatment with the antagonist suppressed these inhibitory effects.

Animals↗
PubMed2001

Emergency treatment of hypothermia.

This review considers several recent concepts regarding aetiology and treatment of accidental hypothermia. The importance and effectiveness of shivering heat production in the attenuation and reversal of hypothermia is described. Immediately following removal from cold stress, the patient is in danger of a deteriorating condition that may be due to collapse of arterial pressure and/or continued decrease of core temperature. Several controversies are discussed. It is advised that, when possible, patients should be actively but gently warmed as soon as possible (especially if arrival at the emergency department will take greater than 45 min). Extra time should be taken to check for life signs before cardiopulmonary resuscitation is initiated. Chest compressions should proceed at regular normothermic rates and care should be taken to not overventilate the patient. In the emergency department, several factors should be considered before deciding on a treatment regimen. These factors include level of consciousness, cardiovascular stability, core temperature and the direction of change of core temperature. It may be advantageous to transport the more severely hypothermic patient to a more advanced care facility even though transport time may be greater.

Algorithms↗
PubMed1992

Acute exposure to cold air and metabolic responses to exercise.

Acute exposure of the whole body to cold air activates thermoregulatory mechanisms which may influence the physiological responses to exercise. Interactions between cold stress and exercise greatly depend on the intensity of cold stimulation. During exposure to moderate cold (MC) peripheral vasoconstriction shifts part of the blood from the periphery to the core, increasing the central volume and the ventricular filling. When an incremental exercise is performed in MC, the persistence of cutaneous vasoconstriction alters the cardiovascular pattern. Moreover, a delayed onset of the increase in plasma lactate concentration (LA) is found and LA remains lower for submaximum exercise intensities. Simultaneously a greater plasma norepinephrine (NA) response is observed. In addition to cutaneous vasoconstriction shivering thermogenesis occurs during exposure to severe cold (SC) which increases heat production. During incremental exercise, the oxygen consumption (VO2) and the expired minute ventilation (VE) are higher for each exercise intensity. However the ventilatory equivalent (VCO2/VO2) does not change significantly. The increased ventilatory response seems to remain a pure reaction to increasing metabolic demand. The ventilatory threshold occurs at the same exercise intensity but at a higher VO2 and VE than in warm conditions. According to the intensity of cold stress the VO2 level may be similar, increased or decreased at exhaustion. The LA is higher for light exercise intensities, lower for heavy exercise intensities and recovery. Simultaneously a greater NA was found with no change in plasma epinephrine response.

Adult↗
PubMed1992

Energy metabolism during cold exposure.

Recent advances on the influence of cold exposure on energy metabolism in animals and humans are summarized. Although the cold-induced enhancements in carbohydrate metabolism have been the focus of numerous studies, it was only recently that pieces of evidence from animal studies have suggested that cold exposure exerts an insulin-like effect on peripheral tissue glucose uptake, which appears to proceed primarily via insulin-independent pathways. Interestingly, this phenomenon was observed in insulin-sensitive tissues of warm- a well as cold-adapted rats. Whereas previous human studies have concentrated on the cold-induced changes in basal levels of hormones and metabolic substrates, recent work from our laboratory has demonstrated that exposure to cold at rest shifts substrate utilization from mainly lipids at thermal neutrality to carbohydrates, representing the main fuel for shivering thermogenesis. Further investigation has revealed that the marked increment in carbohydrate oxidation in cold-exposed humans is derived from a greater utilization of both circulating glucose and intramuscular glycogen. With respect to lipid metabolism, recent studies have shown that the cold-induced increase in lipid oxidation in man is fuelled primarily by the fatty acids released from white adipose tissue triglycerides (TG) and possibly intramuscular TG, not plasma TG. One practical application of this work on energy metabolism in the cold resides in the pharmacological approach to improve cold tolerance, where pharmacological agents that alter energy metabolism and substrate utilization could be used to enhance cold thermogenesis and produce warmer body temperatures.

Animals↗
PubMedDate not supplied

When nonshivering thermogenesis equals maximum metabolic rate: thermal acclimation and phenotypic plasticity of fossorial Spalacopus cyanus (Rodentia).

Many small mammals inhabiting fluctuating and cold environments display enhanced capacity for seasonal changes in nonshivering thermogenesis (NST) and thermoregulatory maximum metabolic rate (MMR). However, it is not known how this plasticity remains in a mammal that rarely experiences extreme thermal fluctuations. In order to answer this question, we determined body mass (m(b)), basal metabolic rate (BMR), NST, MMR, and minimum thermal conductance (C) on a Chilean fossorial caviomorph (Spalacopus cyanus) from a coastal population, acclimated to cold (15 degrees C) and warm (30 degrees C) conditions. NST was measured as the maximum response of metabolic rate (NST(max)) after injection of norepinephrine (NE) in thermoneutrality minus BMR. Maximum metabolic rate was assessed in animals exposed to enhanced heat-loss atmosphere (He-O2) connected with an open-flow respirometer. Body mass and metabolic variables increased significantly after cold acclimation with respect to warm acclimation but to a low extent (BMR, 26%; NST, 10%; and MMR, 12%). However, aerobic scope (MMR/BMR), calculated shivering thermogenesis (ST), and C did not change with acclimation regime. Our data suggest that physiological plasticity of S. cyanus is relatively low, which is in accordance with a fossorial mode of life. Although little is known about MMR and NST in fossorial mammals, S. cyanus has remarkably high NST; low MMR; and surprisingly, a nil capacity of ST when compared with other rodents.

Acclimatization↗
PubMed1994

The mathematical modelling of thermal responses of normal subjects and burned patients.

A model of the human thermoregulatory system has been developed for normal subjects and burned patients treated in the intensive care room at Aberdeen Royal Infirmary. The human body is split into eleven segments, each having core, muscle, fat and skin layers. Heat transport through blood flow and conduction are simulated, and surface heat loss is separated into radiative, convective and evaporative components. Measurement of skin temperature and evaporation of moisture have been made from all sections of the body for 22 normal subjects over a range of environmental temperatures from 20 degrees C to 40 degrees C. The model has been refined to fit the data through manipulation of heat flow commands and temperature set points controlling sweating and shivering. The model has been adapted to describe the responses of burn patients by the introduction of skin layer destruction, increased body metabolism and fluid loss from wounds. Predictions have been compared with measurements made on six patients. The model shows that the ambient temperature at which sweating occurs increases with the area of burn injury, which is confirmed by clinical observations. It has been used to predict optimum environmental temperatures for treatment of patients with burn wounds of varying extent.

Adult↗
PubMed1978

Heat loss during anaesthesia.

The superficial and deep body temperatures of 23 patients were studied during prolonged anaesthesia for microscopic surgery of the fallopian tubes. The patients were divided randomly into three groups, receiving either halothane 0.5%, halothane 1% or low-dose fentanyl as a supplement to nitrous oxide, oxygen and myoneural block. Other variables were kept constant, and the theatre temperature was maintained at 24 degrees C. Temperature changes were unrelated to both the type of anaesthesia and the percentage of subcutaneous fat to body weight. Halothane 1% decreased the rate of heat loss in the 3rd hour. Large heat losses occurred on transfer to the recovery room, where the total heat produced increased rapidly and was unrelated to shivering.

Adult↗
PubMed1991

Clonidine decreases postoperative oxygen consumption in patients recovering from general anaesthesia.

Twenty ASA I patients, undergoing thyroid surgery were allocated randomly to receive at the end of surgery either an isotonic saline solution or clonidine 2 micrograms kg-1 i.v. administered over 20 min. Oxygen consumption (VO2) and carbon dioxide production (VCO2) were measured during recovery in patients breathing spontaneously with a head canopy system. Clonidine was found to attenuate the increase in VO2 and VCO2 associated with recovery from anaesthesia. The effect of clonidine was associated with a reduction in shivering. Sedative and analgesic properties of clonidine may also contribute to the reduction in metabolic demand during recovery from anaesthesia.

Adult↗
PubMed1979

Side effects of long-term treatment with human leukocyte interferon.

Twenty-nine patients, 27 of them with osteosarcoma and two with juvenile laryngeal papilloma, were followed for an aggregate period of 365 months, during which time they received long-term treatment with human leukocyte interferon. The interferon was given by intramuscular injection either daily or three times a week; the dose was 3 x 10(6) standard units. During the course of the treatment, 12 distinct symptoms were recognized as possible side effects of the drug; the three most frequent symptoms occurring after injection were fever, local pain, and shivering. All but three of the patients reported between one and five symptoms. Partial purification of the interferon reduced or eliminated some, but not all, of the symptoms. All of the patients were treated on an ambulatory basis, and none had to discontinue the interferon therapy because of the side effects.

Adolescent↗
PubMed2001

Only UCP1 can mediate adaptive nonshivering thermogenesis in the cold.

Adaptive nonshivering thermogenesis may have profound effects on energy balance and is therefore therefore is a potential mechanism for counteracting the development of obesity. The molecular basis for adaptive nonshivering thermogenesis has remained a challenge that sparked acute interest with the identification of proteins (UCP2, UCP3, etc.) with high-sequence similarity to the original uncoupling protein-1 (UCP1), which is localized only in brown adipose tissue. Using UCP1-ablated mice, we examined whether any adaptive nonshivering thermogenesis could be recruited by acclimation to cold. Remarkably, by successive acclimation, the UCP1-ablated mice could be made to subsist for several weeks at 4C during which they had to constantly produce heat at four times their resting levels. Despite these extreme requirements for adaptive nonshivering thermogenesis, however, no substitution of shivering by any adaptive nonshivering thermogenic process occurred. Thus, although the existence of, for example, muscular mechanisms for adaptive nonshivering thermogenesis has recurrently been implied, we did not find any indication of such thermogenesis. Not even during prolonged and enhanced demand for extra heat production was any endogenous hormone or neurotransmitter able to recruit any UCP1-independent adaptive nonshivering thermogenic process in muscle or in any other organ, and no proteins other than UCP1-not even UCP2 or UCP3-therefore have the ability to mediate adaptive nonshivering thermogenesis in the cold.

Adaptation, Physiological↗