Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SHIVERING”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources
PubMed1976

Threshold temperatures for shivering in acute and chronic hypercapnia.

Threshold temperatures for shivering in acute and chronic hypercapnia were determined in guinea pigs by measuring the time course of cervical cord temperature, skin temperature, oxygen consumption (Vo2), and electrical muscle activity during cold exposure (15 degrees C). Prior to acute exposure to CO2, the shivering threshold was determined in each animal during control conditions breathing air. With increasing CO2 concentrations (5,7.5, and 15% CO2) the shivering thresholds fell to lower temperatures, decreasing by approximately 40 degrees C at 15% CO2. The shift of the shivering threshold to lower values found during acute exposure to 15% CO2 was reversed after chronic exposure to 15% CO2 for 3 days, which marks the time of metabolic adaptation to CO2.

Acute Disease↗
PubMed1990

Effect of adrenaline, fentanyl and warming of injectate on shivering following extradural analgesia in labour.

This prospective, controlled study was undertaken to determine whether addition of adrenaline or fentanyl to bupivacaine or warming of the injectate had any effect on the incidence of shivering following extradural analgesia in the labouring parturient. Eighty-four patients were sequentially allocated to four groups (control, warm injectate, extradural adrenaline and extradural fentanyl). The adrenaline group had the highest incidence of shivering, the warm injectate and fentanyl groups the lowest. Extradural fentanyl also seemed promising in reducing shivering in pre-block shiverers. This paper also explores the rapidity of temperature decay of solutions of bupivacaine in different clinical situations.

Adult↗
PubMed2004

Lower limb wrapping prevents hypotension, but not hypothermia or shivering, after the introduction of epidural anesthesia for cesarean delivery.

The decrease of arterial blood pressure and body temperature after epidural or spinal anesthesia is thought to be the result of sympathetic block, which could cause pooling and redistribution of blood into the lower extremities. Studies have demonstrated that leg wrapping with elastic bandages may reduce the incidence of hypotension after spinal anesthesia. We tried to extend these previous observations to epidural anesthesia by testing the hypothesis that leg wrapping with elastic bandages should decrease the incidence of hypotension in patients receiving epidural anesthesia. Moreover, we evaluated the effect of this maneuver as regards hypothermia and shivering. Sixty parturients were randomly allocated to receive either leg wrapping with tight elastic bandages (leg-wrapped group) or not (control group) before anesthesia. Sublingual temperature was observed at five periods: baseline, immediately after epidural anesthesia, abdominal skin disinfection, skin incision, and delivery. Hypotension and shivering during the observation periods were also recorded. The incidence of hypotension was significantly less frequent (P = 0.03) in the leg-wrapped group (23%) compared with the control group (50%). Shivering incidences were similar in both groups (70% versus 70%). Sublingual temperature decreased significantly (P < 0.001) throughout the procedure in each group. However, no differences were found between the two groups at each designated observation, even if compared by the magnitude of temperature decrease. We conclude that although leg wrapping with elastic bandages prevents maternal hypotension after epidural anesthesia, it does not reduce the incidence or magnitude of hypothermia or prevent shivering.

Adult↗
PubMed2001

Hypothalamic region facilitating shivering in rats.

Although the posterior part of the hypothalamus has long been considered important for thermoregulatory shivering, it is unknown whether the neurons there or the passing fibers are implicated in the response. Exposure of urethane-anesthetized rats to cold (15-21 degrees C) elicits shivering. An injection of muscimol (0.5 mM), a GABA(A) receptor agonist, into the medial part of the hypothalamus, including the dorsomedial and posterior nuclei, suppressed the cold-induced shivering. This result suggests that neurons having an excitatory effect on shivering are in this region of the hypothalamus.

Animals↗
PubMed1999

Anesthesia and postoperative shivering: its etiology, treatment and prevention.

Postoperative shivering following anesthesia varies between 5 and 65%. The etiology of postoperative shivering is unclear. Pharmacologic agents are still the most popular mode of treatment for postanesthetic shivering, such as meperidine, clonidine and physostigmine. Nonpharmacologic approaches such as maintaining ambient temperature and warming air blankets and intravenous infusions remain as effective preventive measures for postoperative shivering. This review will address its etiology, treatment and prevention.

Anesthesia↗
PubMed2003

Force control of isometric elbow flexion with visual feedback in cold with and without shivering.

BACKGROUND: Exposure to cold impairs manual performance through effects on muscle tissue and control mechanisms. The purpose of this study was to assess the influence of increased muscle tone and shivering on ability to maintain required force during isometric flexion over a wide range of effort levels. METHODS: Lightly clad male subjects (n = 6) were exposed to thermoneutral air (TN, 27 degrees C) for 30 min, or to cold air (CA, 10 degrees C) for 30 min followed by a cold drink (1 L, 8 degrees C) to cause vigorous shivering (SH). At the end of each condition, subjects performed isometric elbow flexion at 10, 20, 40, and 80% of individual maximal voluntary contraction (MVC) for 10 s each, using digital visual feedback to control the force. We analyzed mean force output (F), the coefficient of force variation (FCv), information transmission (F/SD), and the coefficient of force auto-correlation (Ra), and the averaged electromyogram (aEMG) from elbow flexors, elbow extensor, and pectoral girdle muscles. RESULTS: Compared with TN, CA with increased muscle tone raised the aEMG by 5-30% but did not impair any of the force characteristics. In SH, F was not affected, while FCv and Ra were significantly increased at 10% MVC, while aEMG increased by 30-400% depending on the specific muscle and MVC level. CONCLUSION: Neither thermoregulatory muscle tone nor shivering influenced the control of force output during isometric elbow flexion, except that at the lowest MVC (10%) the force output was more variable during shivering.

Adult↗
PubMed2002

[Incidence of postoperative shivering in relation to the time of sevoflurane discontinuation].

OBJECTIVES: We aimed to determine whether early termination of sevoflurane administration lowers the incidence of postanesthetic shivering. MATERIAL AND METHODS: Eighty ASA I-III patients were randomized to two groups of 40 (Group A and Group B). All were premedicated with oral bromazepam. Fentanyl (2 micrograms/Kg), propofol (2.5 mg/Kg) and atracurium (0.5 mg/Kg) were used for induction. Anesthesia was maintained with sevoflurane in 60% N2O in oxygen at 1 maximum alveolar concentration, with boluses of fentanyl and atracurium on demand. Sevoflurane administration was terminated 30 minutes before awakening in group A and 10 minutes before awakening in group B. After termination, 60% N2O in oxygen was used in both groups. Mean blood pressure, heart rate and peripheral and core temperatures were measured at 5 minutes intervals during surgery. Postoperative shivering was recorded until one hour after awakening. RESULTS: Patient characteristics and duration of anesthesia were similar in both groups. The incidence of shivering was significantly lower in group A (4%) than in group B (57%). No significant differences were observed in other variables. CONCLUSIONS: The important observation in this study was that the incidence of postoperative shivering in group A was lower than in group B and lower than the incidences reported in other similar studies.

Adult↗
PubMed2006

Total intravenous anesthesia with propofol and remifentanil is associated with a nearly twofold higher incidence in postanesthetic shivering than desflurane-fentanyl anesthesia.

BACKGROUND: Postanesthetic shivering (PAS) is a frequent side effect of general anesthesia. Previous reports on the incidence of PAS of propofol for the induction or maintenance of anesthesia have been controversial, but have not been studied in detail. The aim of the present study was to evaluate the incidence and severity of PAS in total intravenous anesthesia (TIVA) with propofol and remifentanil compared with an inhalative anesthesia. MATERIAL/METHODS: After ethics committee approval and written informed consent from the patients, 53 patients scheduled for urologic, gynecologic, or surgical operations were studied for shivering postoperatively using a five-point rating scale. They received desflurane-fentanyl based anesthesia (n=27) or TIVA with propofol and remifentanil (n=26). Hemodynamics and temperature were measured after induction of anesthesia (T0), and 5 min (T1), 15 min (T2), 30 min (T3), and 60 min (T4) after reaching the postanesthetic care unit (PACU). RESULTS: In the TIVA group, 18/26 (69.2%) patients suffered from PAS compared with 10/27 (37%) in the desflurane-fentanyl group (P<0.02). The severity of shivering was significantly higher with TIVA than with desflurane (P<0.02), whereas temperature showed no significant difference between the study groups. CONCLUSIONS: Postanesthetic shivering appears significantly more frequently and intensively after TIVA with propofol and remifentanil compared with an inhalative anesthesia with fentanyl and desflurane.

Aged↗
PubMed1991

A comparative study of pharmacological versus nursing interventions in the treatment of postanesthesia shivering.

Postanesthesia shivering (PS) is a potential complication for any surgical patient requiring anesthetic agents. PS has been shown to increase oxygen consumption up to sevenfold, compromising patient oxygenation in the postanesthesia period. The purpose of this study was to compare the effectiveness of radiant heat, radiant heat plus meperidine, and radiant heat plus fentanyl in the treatment of PS in PACU patients. An experimental design study using three groups was conducted using the Neuman Systems Model as a conceptual framework. Twenty-nine subjects were randomized into three groups and were blinded to the treatment, as was the investigator. All subjects received one blanket and radiant heat. Groups I, II, and III received the following respective treatments: normal saline, meperidine (12.5 mg every 5 minutes up to a maximum of 50 mg), and fentanyl (25 micrograms every 5 minutes up to a maximum of 100 micrograms). Data collection included surface electromyography, mean arterial pressure (MAP), heart rate (HR), rate-pressure product (RPP), respiratory rate, and oxygen saturation every 5 minutes until shivering stopped or maximum drug dosages were reached. Data showed no statistically significant differences among the three groups with regard to effectiveness of treatment (F = .507, P = .61). Significant reductions in MAP, HR, RPP, and respiratory rate were found (P = .001) at the end of shivering. Significant differences were also found between the shivering and nonshivering subjects with regard to length of anesthesia, age, body surface area (P less than .01), weight, body mass index (P less than .001), and intravenous fluid administration (P less than .05). Results suggest that radiant heat is as effective alone as it is in combination with pharmacological intervention for the treatment of PS.

Adolescent↗
PubMed1979

Bimodal relationship of human tremor and shivering on introduction to cold exposure.

Four subjects were exposed to an environmental challenge of -12 degrees C for 15 min in four conditions of exposure: 1) clothed body and clothed arm, 0.5 clo units: 2) clothed body and exposed arm, 0.4 col; 3) exposed body and exposed arm, 0.1 clo: 4) exposed body and clothed arm, 0.2 clo. Core temperature, surface temperature of the right arm, perceived thermal comfort, EMG indicated onset of shivering, and the frequency of tremor using accelerometry were monitored and data collected every 30 s. The results indicate that tremor frequency significantly increases with cold exposure, but that a significant drop in tremor frequency precedes the onset of shivering. It is suggested that pre-shivering tetany occurs prior to the onset of shivering, acts as a load upon the lever of the hand and reduces the oscillation of the limb.

Adult↗
PubMed1981

[Participation of the vestibular apparatus in regulating shivering].

Participation of the vestibular apparatus in the control of bioelectrical activity and function of muscle motor units was studied in experiments on cats with cold shivering. It was shown that the shivering was suppressed by limitation of the vestibulospinal effects whereas stimulation of the vestibular apparatus enhanced it. Suppression of the shivering after delabyrinthation manifested both in the increased frequencies of impulses in the active motor units and in the recruitment of new units, previously "silent". Participation of the vestibular apparatus in cold shivering control and the mechanism by which the animal's posture is formed thereby restricting the heat-release surface are discussed.

Animals↗
PubMed1993

Suppression of shivering by breath holding, relaxation, mental arithmetic, and warm water ingestion.

Four methods of suppressing cold-induced shivering were evaluated in 26 young male volunteers exposed to 0.0 +/- 1.0 degrees C air for 135 min. Voluntary relaxation of musculature (R), breath holding (BH), warm (50 degrees C) water ingestion (W), and performance of a mental arithmetic task (MA) were applied in a counterbalanced order following 2 h of cold exposure. Surface electromyograms of seven muscles were recorded and converted to root mean square voltage (RMS) as a measure of shivering intensity. Mean skin and rectal temperatures decreased significantly, 4.9 degrees C and 0.3 degrees C, respectively (p < or = 0.01). Mean reduction of EMG activity was 35% during R, 24% during BH, 18% during MA, and 5% during W. R was significantly more effective than BH, MA, and W, and BH and MA were significantly more effective than W in reducing shivering. These results indicate that, at small decreases in rectal temperature, shivering can be voluntarily suppressed to some extent during relaxation, breath holding, and mental arithmetic.

Adult↗
PubMed1998

Postanaesthetic shivering--a comparison of thiopentone and propofol.

One hundred and sixty patients undergoing minor surgical procedures were randomly allocated to receive either thiopentone or propofol for induction of anaesthesia. All patients were assessed in the recovery period for the development of postanaesthetic shivering. Twenty patients (25%) in the thiopentone group and 8 patients (10%) in the propofol group developed postanaesthetic shivering (p < 0.05). There was no statistically significant difference in tympanic temperature between shivering and nonshivering patients. Propofol as an induction agent is associated with a lower incidence of postanaesthetic shivering as compared to thiopentone.

Adult↗
PubMed2002

CNS myelinogenesis in vitro: myelin basic protein deficient shiverer oligodendrocytes.

The shiverer mutant mouse is an autosomal recessive mutant characterized by incomplete myelin sheath formation in the central nervous system (CNS). Such mice contain a deletion in the MBP gene, do not produce MBP proteins, and have little or no compact myelin in the CNS. To investigate the myelin sheath formation in shiverer mutant mice resulting from the absence of compact myelin, firstly we developed new methods for generating oligodendrocyte precursor cells (OPCs) from an E17 mouse brain, and examined homozygous shiverer (shi/shi) OPCs with respect to myelinogenesis in vitro. After treatment of shi/shi OPCs in vitro with PDGF or bFGF, proliferation of shi/shi OPCs was enhanced similar to that observed in wild-type OPCs. The majority of cells from the shiverer mutant mouse, however, remained as A2B5-immunoreactive early OPCs. To determine which molecular events affect the differentiation of shi/shi OPCs, we determined the signaling pathway that could be responsible for activating myelin sheath-specific proteins. We found that the developmental schedule of shi/shi OPCs in vitro was accelerated by the addition of cyclic AMP analogs, dibutyryl cAMP (dbcAMP). Treatment of shi/shi OPCs with dbcAMP had significant effect on the differentiation of OPCs that became MAG-expressing oligodendrocytes. To further determine the possible mechanism involved in the activation of MAG by dbcAMP, we examined the cAMP-dependent signaling cascades. The activation of JNK was markedly stimulated by treatment with dbcAMP, and the phosphorylation of transcription factor ATF-2 was also stimulated by dbcAMP. We demonstrated that the MAG-positive shi/shi oligodendrocytes extend processes around axons and finally covered the axon, this was clearly observed by immunocytochemistry of shi/shi oligodendrocyte-DRG cocultures. These results suggest that ATF-2 coupled to specific signal transduction cascades plays an important regulatory role in MAG expression at a specific stage of shi/shi oligodendrocyte differentiation, and OPCs grow to become myelin-forming cells with numerous cell processes that wraps around an axon to form a thin myelin sheath.

Activating Transcription Factor 2↗
PubMed1996

Order-disorder phenomena in myelinated nerve sheaths. VI. The effects of quaking, jimpy and shiverer mutations: an X-ray scattering study of mouse sciatic and optic nerves.

We report the X-ray scattering study of sciatic and optic nerve myelin from shiverer, jimpy and quaking mice mutants and from the corresponding controls. These three mutations are known to affect dramatically central nervous system (CNS) myelin and to induce comparatively minor alterations in peripheral nervous system (PNS) myelin. Scattering experiments and data reduction were carried out using the techniques and algorithms developed in our laboratory and previously applied to several problems involving the structure of myelin. In sciatic nerve the fraction of myelin elementary pairs of membranes (total myelin) decreases in shiverer and quaking nerves (by approximately 30%) but not in jimpy nerves; in all three mutants the fraction of myelin membrane pairs that are not regularly stacked in the sheaths (loose myelin), the average number of membranes per sheath and the packing disorder are the same as in the control nerves; the repeat distance D and the membrane distance Dcyt across the cytoplasmic space increase in shiverer and decrease in jimpy; in quaking, D also decreases and the decrease is smaller than in jimpy and is not specific for Dcyt; small changes are also observed in the electron density profiles. As for the optic nerve the myelin content decreases dramatically in the three mutants; the very weak signal attests to a tiny amount of pairs of membranes structurally similar to normal CNS myelin. It is surprising that the structure of CNS myelin should be almost normal in the absence of the major structural components, namely myelin basic protein (MBP) for shiverer of proteolipid protein (PLP) for jimpy. The question arises whether the composition of the residual pairs of membranes, operationally identified as myelin in the X-ray scattering experiments, mirrors the composition determined by chemical means on the fraction of nerve tissue histologically identified as myelin, or whether in all circumstances it remains approximately the same.

Animals↗
PubMed1980

2'-3'-cyclic nucleotide 3'-phosphohydrolase activity in the central nervous system of a myelin deficient mutant (Shiverer).

Shiverer is a recessive autosomal mutant characterized by the deficiency of the myelin in the central nervous system. 2',3'-Cyclic nucleotide 3'-phosphohydrolase (CNPase) activity of the various parts of the central nervous system from the Shiverer did not differ significantly from those of the control. The analysis of the protein profiles of the purified myelin from the Shiverer showed a greatly decreased proportion of proteolipid protein, and almost complete absence of small and large basic proteins, and intermediate protein. Woldgram protein accounted for a much larger percentage of the total myelin protein than is the case in myelin from the control. Proteolipid protein, small and large basic proteins, and intermediate protein were found to be undetectable or decreased in various parts of the central nervous system from the Shiverer. Morphological observation by optic and electron microscope showed that the myelination of the optic nerve was equally affected as the spinal cord.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1984

Cell lineage analysis of Schwann cells in the PNS determined by shiverer-normal mouse chimeras.

The myelin of the peripheral nervous system from the shiverer mutant mice is characterized by the absence of myelin basic protein, while the other myelin protein components are present at normal levels. Myelin lamella formation is normal in the shiverer mutant. Therefore, by using antiserum against myelin basic protein, we can distinguish the shiverer from the wild-type control myelin immunohistochemically. To study the cell lineage of Schwann cells, chimeras produced by the aggregation of eight-cell embryos from wild-type mice and shiverer mice have been used. Using myelin basic protein as a marker, it was observed that Schwann cells in the sciatic nerve existed as patches of cells with like-genotype. The patches occurred in a linear array along the axons with some intermingling of Schwann cells. Complete randomization by intermingling of Schwann cells was not observed and clones of Schwann cells may persist as contiguous groups throughout peripheral nerve development.

Animals↗
PubMed1986

Alteration of the primary pattern of central myelin in a chimaeric environment--study of shiverer----wild-type chimaeras.

Using chimaeras produced from the shiverer mutant with a BALB/C background (white coat color) and normal mice of the C57BL/6N strain (black coat color) by the aggregation method, the morphological patterns of the central myelin sheaths were examined by electron microscopy, with special reference to the structure of the myelin lamellae of the one genotype in an environment dominated by the other genotype. The results obtained may be summarized as follows. The oligodendrocytic processes of both genotypes are able to interact independently with the axon unrelated to its genotype. The lamellar structure of the myelin sheath, i.e., whether or not it is composed of alternating major dense and intraperiod lines, is primarily determined by the genotypes of the oligodendrocytes concerned. The processes of shiverer oligodendrocytes can spirally enwrap axons in the chimaeric CNS which shows dominance of the normal genotype. In contrast, in the environment of shiverer dominance, the spiral arrangement of the oligodendrocytic processes of the normal genotype is often disturbed, probably by the oligodendrocytic processes of the shiverer genotype. Thus, the primary pattern of the myelin sheaths can be altered under the chimaeric condition, and the formation of the myelin sheaths depends essentially on the behavior of the oligodendrocytic processes, which is determined by the genetic specificity.

Animals↗