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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Control mechanism of the respiratory muscle during forced expiration was analyzed. Respiratory flow. EMG of the intercostal muscle (IC), external oblique (EO) and internal oblique (IO) abdominal muscle were analyzed in eleven healthy volunteers. The pattern of EMG activity during forced expiration could be classified according to its shape i.e., taper- or hill-shaped. The taper shape was found in 7 of 9 subjects for IC and in 8 of 11 subjects for EO. The hill shape was found in 4 of 6 subjects for 10. Twelve consecutive trials without intervals did not alter the pattern of flow-volume curve, activity of respiratory muscle and frequency component (i.e., H/L ratio). When the expiratory circuit was obstructed for a short interval during forced expiration, the rise in pleural pressure was slight but that in oral pressure was large, and the activity of respiratory muscle decreased for a short period. The latencies from the onset of expiratory circuit obstruction to the reduction in EMG activity were 61.5-100 msec. In IC, 61.5-106.5 msec in EO. and 58.0-92.3 msec in 10. These values did not differ significantly any given subject. Airway anesthesia with xylocaine did not alter latency. In conclusion, the pattern of respiratory muscle activity for forced expiration is predetermined and is specific for each muscle. Negative feedback from receptors in airway or in respiratory muscle was strongly suggested. Repetitive trials up to twenty times did not cause respiratory muscle fatigue.
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PMID:[Control mechanism of the respiratory muscle during forced expiration]. 217 Jul 26

L-Glutamate and related excitatory amino acids (EAA) are firmly established as major excitatory synaptic transmitter substances in the vertebrate central nervous system. Questions which have been addressed include: How many receptors are there for the EAAs?; What ion channels and/or 'second-messenger' systems are regulated by these receptors?; What are the roles of EAAs in higher neural functions?; Are they involved in neurological disorders? EAA receptors appear not only to mediate normal synaptic transmission along excitatory pathways but also to participate in the modification of synaptic connections during development. However, overaction of receptors can also mediate neuronal degeneration and even cell death. NMDA receptor antagonists markedly attenuate neuronal necrosis. Therefore, it appears that ischemia- and hypoglycemia-associated brain damage results not from a lack of energy substrates but rather via the mediation of NMDA receptors and 'excitotoxic' mechanisms. The action of ketamine anesthesia is closely associated with a block of the NMDA receptor. Ketamine binds to a site within the lumen of the NMDA-activated channel and can become trapped there when the channel closes. Current evidence indicated that NMDA receptor antagonists will be of value for the treatment of delayed neuronal death. NMDA receptor will lead to understanding the mechanisms underlying learning and memory, the control of neuronal excitability and neuronal death.
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PMID:[Synaptic mechanisms of excitatory amino acids and NMDA receptor mediated brain excitability]. 217 10

Ultrasound is ideally suited for imaging of renal calculi for extracorporeal shock wave lithotripsy. Ultrasound can localize radiolucent stones, monitor fragmentation in real time, and differentiate the stone from a stent. Its use significantly reduces the radiation exposure to patient and operator, which is particularly desirable in the pediatric patient. Furthermore, sonography-guided lithotripsy can reveal any incidental finding in the affected kidney that may require further evaluation and familiarizes the operator with this increasingly useful imaging method. The ultrasound-guided Sonolith 3000 with its enlarged ellipsoid aperture has a decreased energy focus size and voltage, permitting fragmentation with reduced anesthesia requirements. The initial extracorporeal shockwave lithotripsy (ESWL) machine, the Dornier H3, uses fluoroscopy for stone localization and treatment monitoring. Although this imaging method has the benefit of being familiar to urologists, it has some drawbacks, such as difficulty in imaging some types of stones and the radiation exposure of the operator and the patient. We have been using the Technomed Sonolith 3000 ESWL machine, which uses ultrasound to localize stones. During this experience, we have found a number of obvious and not so obvious benefits. For example essentially all calculi are echogenic, irrespective of their radiologic density. Moreover, with ultrasound, fragmentation can be monitored by real-time imaging, making determination of the treatment end point easier, and the stone and stent can be differentiated clearly. Ultrasound also can reveal other pathology and eliminates radiation exposure. Moreover, an ultrasound-guided ESWL unit familiarizes the operator with ultrasound techniques, and the same machine can be used for biliary lithotripsy. All of these features make ultrasound imaging for ESWL desirable.
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PMID:Benefits of an ultrasound-guided ESWL unit. 220 66

Sixty patients who presented for day-case dilatation and curettage were allocated randomly to receive either thiopentone or propofol for induction and maintenance of anaesthesia. One anaesthetist administered all the anaesthetics whilst all assessments were made by one other. The results indicate that early recovery of memory function, critical flicker fusion frequency and subjective feelings of tiredness, drowsiness and alertness were superior in the propofol group. There was a significant difference in subjective feelings of tiredness and drowsiness recorded by the two study groups at 24 hours. Memory function assessed by Wechsler logical memory function passages at 24 hours was impaired in the propofol group in comparison to a group of 'reference' subjects.
Anaesthesia 1990 Nov
PMID:Recovery after day-case anaesthesia. A 24-hour comparison of recovery after thiopentone or propofol anaesthesia. 225 83

Anatomy, injury-mechanism and classification will be illustrated with a casuistry of the rate isolated luxation of the ulnar head. Diagnosis is established clinically and with comparative X-rays. In our case the luxation was irresponsible in general anaesthesia and had to be succeeded by open reposition with temporary pin-fixation. Postoperatively a cast up to the upper arm is necessary for six weeks. With the removal of the plaster the wire pins also must be immediately withdrawn, as to evade complications like fatigue-breakage of the implanted material. With adherence to this therapeutic scheme operative treatment is not problematic and - by means of posttraumatic physical therapy - shows a good functional result.
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PMID:[Isolated dislocation in the distal radio-ulnar joint]. 226 Feb 31

A model of hemorrhagic shock (arterial mean pressure = 40 mmHg) terminated by death in all cases was developed in 21 dogs. The study was addressed to investigate the central respiratory response, development of diaphragmatic fatigue (FD) and the influence of the suppression of spontaneous rhythmic respiratory muscle activity by mechanical ventilation during shock. We measured diaphragmatic force: transdiaphragmatic pressure (Pdi), spontaneous and stimulated electrical activity of the diaphragm (integrated and rectified electromyogram: Edi) tracheal occlusion pressure (P 0, 1) cardiac output (Q) and survival, ventilatory variables were also measured. We constructed Pdi/Frequency and Pdi/Edi curves. The phrenic nerves were stimulated: 1) by bipolar electrodes at the 5th cervical roots or 2) by a bipolar electrode catheter introduced through the left jugular vein. The animals were divided in 3 groups: 1) during spontaneous breathing (light pentobarbital anesthesia and positive corneal reflex) Pdi/Frequency curves and Pdi response to single twitch were measured (n = 9); 2) evolution of Edi and Pdi/Edi curves during spontaneous breathing (n = 6); 3) Pdi/Frequency curves (n = 6) during mechanical ventilation (ARM). We found (groups 1, 2) initially compensated (increased P 0, 1 and hyperventilation: table 1) metabolic acidosis, followed by mixed acidosis after FD (fall in Pdi/Frequency: Fig. 1, and Pdi/Edi: Fig. 2, 3, table 3) and associated with falling respiratory frequency (Fr). During hyperventilation, central respiratory drive/minute: Edi.Ti.Fr (Ti = inspiratory time, sec) increased and fell later during FD, remaining however higher than basal.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Diaphragmatic fatigue in hypovolemic shock]. 229 10

While the consequences of occupational exposure to anesthetic gases and volatile agents on morbidity in operating room staff are controversial (survey in Swiss investigations show a distinct correlation with subjective complaints, e.g. tiredness and headache on the day of exposure (Table 1). In Sweden, rigorous control of occupational exposure to anesthetic gases has prompted development of various scavenging systems, among which the double mask (Fig. 1) is the latest and most advanced. During mask anesthesia, escaping anesthetic gases are evacuated at the point of leakage via a thin slot between a flexible silicone inner mask and a rigid plastic outer mask. A small plate in the mask produces turbulence in the otherwise laminar flow of anesthetic gases, thus reducing the speed of gas leakage. A silicone chamber is mounted on the mask and connected to a fan, requiring a flow of 35 m3/h for optimal function. This chamber does, however, also associate the system with two practical problems: the system with its evacuation tube is heavier to hold than conventional masks, and it is associated with increased dead-space that is only partly minimized by a modification of the Y-connector. While the handling is largely a matter of routine and the weight of the system is minimized when the evacuation tube is arranged to draw slightly upward, the increased dead space may reduce the practicality of the double mask in infants.
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PMID:[The double mask]. 222 17

A questionnaire inquiring about existing and desirable work and rest patterns appeared in a newsletter mailed to about 22,000 anesthesiologists and anesthesiology residents and 24,000 nurse anesthetists (CRNA). Almost 3,000 anonymous replies were received and analyzed. Respondents reported mean work weeks of 47.5 h (CRNA) to 69.8 h (residents), longest continuous period of administering anesthesia without a break of 6.6 h (CRNA) to 7.7 h (residents), and longest period of administering anesthesia with or without breaks of 14.1 h (CRNA) to 20 h (resident). However, the respondents considered it safe to administer anesthesia without a break for 4.2 (CRNA) to 5.2 h (anesthesiologists) and with break for 12.8 h (CRNA) to 15 h (residents). A substantial number of respondents believed that they work at least occasionally beyond their perceived self-limitations. The majority of respondents recalled having made errors in the administration of anesthesia that they attributed to fatigue. These results may not be representative of work patterns or attitudes among American anesthesia providers because of the small sample size and the resultant potential for bias. Yet, the subject deserves attention and further study because fatigue can affect professional performance, ability to learn, and family life.
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PMID:Work and rest cycles in anesthesia practice. 232 88

The cutaneus trunci muscle reflex in guinea pigs was studied with a combination of video analysis, electromyography, lesioning, and light microscopy. The muscle forms a bilateral, subdermal sheet over much of the trunk. Local contractions of the dorsal part of the muscle are produced in response to brief tactile or electrical stimulation of the skin and consist of a twitch centered 1-2 cm rostral of the stimulus site. The reflex receptive field covers most of the thoracic and lumbar dorsal surface. The sensory information is carried via segmental dorsal cutaneous nerves. Receptive fields of adjacent nerves overlap and form rectangular areas perpendicular to the midline, at thoracic levels. Motor innervation projects through the lateral thoracic nerves of the brachial plexus. The motoneurons are located near the cervical thoracic junction (C7-T1). Lesions of the lower thoracic cord indicate that ascending sensory information is carried to the motor nuclei via the ventral half of the lateral funiculus. This pathway conveys information primarily from ipsilateral skin. There is a weaker input from contralateral skin, crossing at segmental levels. Electromyographic responses to brief electrical stimulation of lower thoracic skin occur usually as 10-12 msec bursts at latencies of 10-20 msec, and do not readily habituate or fatigue at stimulus frequencies below 10 Hz. The reflex persists under light pentobarbital anesthesia. This combination of characteristics makes the reflex useful for a variety of physiological and pathophysiological studies.
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PMID:Cutaneus trunci muscle reflex of the guinea pig. 235 54

During the past six years, the procedure now known as liposuction has revolutionized many aspects of cosmetic surgery, including the facelift, and is now finding applicability in other fields of medicine. The profound psychological benefits afforded to persons by facelifting have become increasingly available through the rapid public acceptance of outpatient surgery for this procedure. The latter has been assisted in no small way by the ancillary use of liposuction for facelifting, since liposuction has certainly made the facelift procedure easier and safer. Prior to the advent of liposuction, there were a number of reports in the medical literature about significant complication rates from facelifting, ranging in frequency from 1 to 8%. These included postoperative hematomas, infection, skin slough, significant hair loss, and nerve injury. The author has experienced none of these complications using adjunctive liposuction in over 100 facelifts. Liposuction has allowed treatment of facial areas previously almost unapproachable in facelifting, except perhaps by the most experienced hands. It has permitted the use of facial fat grafting, a further adjunct to the facelift procedure. Liposuction speeds the facelift procedure, lessening operator fatigue while shortening surgical and anesthesia time for the patient. These factors alone would provoke the rapid adoption of liposuction for facelifting, but its use is further solidified by the excellent results possible without resorting to the various complex and sometimes dangerous platysma-splitting and SMAS-undermining procedures often advocated in the past decade. Documentation of such results is provided by Figures 12 through 17. Thus, it seems reasonable to state that liposuction has had a tremendous and lasting impact on the surgical rejuvenation of the face and neck, whether used alone or in conjunction with facelift. It is in facelifting that the nuances and full potential of liposuction come to the fore.
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PMID:Liposuction with facelift surgery. 237 35


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