Resting muscle sounds in anesthetized patients

1998 ◽  
Vol 76 (4) ◽  
pp. 401-406 ◽  
Author(s):  
William P McKay ◽  
Peter H Gregson ◽  
Benjamin WS McKay ◽  
Travis Blanchet
Keyword(s):  
Informed Consent ◽  
Elective Surgery ◽  
Low Frequency ◽  
Muscle Relaxants ◽  
Signal Power ◽  
Contracting Muscle ◽  
Volar Forearm ◽  
Resting Muscle ◽  
Muscle Sounds ◽  
Made In

It is known that contracting muscle makes low frequency sound vibrations.Small vibrations of uncertain origin are found over resting muscle. These could be shown to beof muscle origin if they significantly diminish in response to agents expected to decrease muscleactivity. Thiopental, propofol, and neuromuscular-junction blocking muscle relaxants have suchproperties. Twenty-one subjects slated for elective surgery for which they would routinely beanesthetized and paralysed gave informed consent to having a small accelerometer taped upontheir supine biceps (9 subjects), or volar forearm (12 subjects). Recordings were made in fourstages while subjects: (i) lifted a 2-kg weight just off the sponge armrest on whichtheir outstretched arm lay; (ii) relaxed their arm in the awake state prior toanesthesia; (iii) had anesthesia induced with intravenous thiopental (n = 11)or propofol (n = 10); and (iv) were paralysed. Recordings were digitised at172-Hz and 6-s segments fast Fourier transformed (FFT). Total signal power, as determined bythe area under the power spectrum, was significantly different (p < 0.05) in all stages forthe biceps and in all but stages (iii) from (iv) in the forearm. It appearsthat resting muscle generates measurable vibrations.Key words: muscle sounds, accelerometer, anesthesia.

Resting Mechanomyography After Aerobic Exercise

2004 ◽  
Vol 29 (6) ◽  
pp. 743-757 ◽  
Author(s):  
William P.S. McKay ◽  
Philip D. Chilibeck ◽  
Karen E. Chad ◽  
Brian L.F. Daku
Keyword(s):  
Oxygen Consumption ◽  
Low Frequency ◽  
Young Male ◽  
Cycle Ergometer ◽  
Mechanical Activity ◽  
Biochemical Processes ◽  
Acoustic Myography ◽  
Resting Muscle ◽  
Excess Postexercise Oxygen Consumption ◽  
Muscle Sounds

A number of mechanisms have been proposed for the elevation in oxygen consumption following exercise. Biochemical processes that return muscle to its preexercise state do not account for all the oxygen consumed after exercise. It is possible that mechanical activity in resting muscle, which produces low frequency vibrations (i.e., muscle sounds: mechano-myographic [MMG] activity), could contribute to the excess postexercise oxygen consumption. Therefore the purpose of this study was to determine whether the resting MMG amplitude changes after exercise, and whether the change is related to the elevation in oxygen consumption [Formula: see text] Ten young male subjects (22.9 yrs) performed 30 minutes of exercise on a cycle ergometer at an intensity corresponding to 70%peak [Formula: see text] Oxygen consumption was measured by indirect calorimetry, and MMG by an accelerometer placed over the mid-quadriceps before exercise and for 5.5 hours after exercise. MMG activity, expressed as mean absolute acceleration, was significantly elevated for the 5.5 hours of measurement after exercise (p <  0.05). MMG and [Formula: see text] decayed exponentially after exercise with time constants of 7.2 minutes and 7.4 minutes, respectively. We conclude that muscle is mechanically active following exercise and that this may contribute to an elevated [Formula: see text] Key words: excess postexercise oxygen consumption, muscle sounds, acoustic myography

Blood flow, blood oxygen tension, oxygen uptake, and oxygen transport in skeletal muscle

1964 ◽  
Vol 206 (4) ◽  
pp. 858-866 ◽  
Author(s):  
Wendell N. Stainsby ◽  
Arthur B. Otis
Keyword(s):  
Blood Flow ◽  
Oxygen Uptake ◽  
Oxygen Tension ◽  
Capillary Density ◽  
Muscle Group ◽  
Blood Oxygen ◽  
Histological Techniques ◽  
Contracting Muscle ◽  
Resting Muscle

The effect of changes in blood flow and of blood oxygen tension on oxygen uptake of the in situ gastrocnemius-plantaris muscle group of the dog was examined. Oxygen uptake by resting muscle was not altered by changes in blood flow or blood oxygen tension except when these parameters were reduced below critical values. When the muscle group was contracting once per second, changes in blood oxygen tension were similarly without effect until a critically low value was reached. Although the contracting muscle used eight times as much oxygen per minute as resting muscle, the critical oxygen tension was lower than that for resting muscle. In an attempt to explain this observation the blood-tissue oxygen tension difference was estimated and used in the Krogh equation to calculate capillary density. The capillary density in contracting muscle was found to be much greater than in resting muscle and was about the same as the capillary density measured by others by histological techniques.

Exploring ethical aspects of elective surgery patients’ decision-making experiences

2012 ◽  
Vol 20 (6) ◽  
pp. 672-683 ◽  
Author(s):  
Mei-Ling Lin ◽  
Chuen-Teng Huang ◽  
Hsien-Hsien Chiang ◽  
Ching-Huey Chen
Keyword(s):  
Decision Making ◽  
Informed Consent ◽  
Healthcare Professionals ◽  
Elective Surgery ◽  
Phenomenological Approach ◽  
Healthcare Personnel ◽  
Decision Making Process ◽  
Ethical Aspects ◽  
Southern Taiwan ◽  
Colaizzi's Method

The practice of respecting patients’ autonomy is rooted in the healthcare professionals’ empathy for patients’ situations, without which appropriate supports to the patients during the informed consent process may be remarkably moderated. The purpose of this study was to explore elective surgery patients’ experiences during their decision-making process. This research was conducted using a phenomenological approach, and the data analysis was guided by Colaizzi’s method. A total of 17 participants were recruited from a hospital in southern Taiwan. Two major themes emerged from the analyses: (a) a voluntary yet necessary alternative—to undergo a surgery and (b) alternatives compelled by the unalterable decision—the surgery. It was concluded that unless healthcare professionals can empathize with the distressed situation of their patients who are facing elective surgery, the practice of informed consent may become merely a routine. Nurses can be the best advocates for patients and facilitators to enhance communication between patients and healthcare personnel.

Effects of an Intubating Dose of Succinylcholine and Rocuronium on the Larynx and Diaphragm 

1999 ◽  
Vol 90 (4) ◽  
pp. 951-955 ◽  
Author(s):  
Gilles Dhonneur ◽  
Krassen Kirov ◽  
Velislav Slavov ◽  
Philippe Duvaldestin
Keyword(s):  
Elective Surgery ◽  
Onset Time ◽  
Neuromuscular Blocking ◽  
Blocking Effect ◽  
Muscle Relaxants ◽  
Adductor Pollicis ◽  
Maximum Effect ◽  
Adductor Pollicis Muscle ◽  
Adductor Muscles ◽  
Before And After

Background Paralysis of the vocal cords is one objective of using relaxants to facilitate tracheal intubation. This study compares the neuromuscular blocking effect of succinylcholine and rocuronium on the larynx, the diaphragm, and the adductor pollicis muscle. Methods Electromyographic response was used to compare the neuromuscular blocking effect of succinylcholine and rocuronium on the laryngeal adductor muscles, the diaphragm, and the adductor pollicis muscle. Sixteen patients undergoing elective surgery were anesthetized with propofol and fentanyl, and their tracheas were intubated without neuromuscular blocking agents. The recurrent laryngeal and phrenic nerves were stimulated at the neck. The electromyographic response was recorded from electrodes placed on the endotracheal tube and intercostally before and after administration of 1 mg/kg succinylcholine or 0.6 mg/kg rocuronium. Results The maximum effect was greater at the adductor pollicis (100 and 99%) than at the larynx (96 and 97%) and the diaphragm (94 and 96%) after administration of succinylcholine and rocuronium, respectively (P &lt; or = 0.05). Onset time was not different between the larynx (58+/-10 s), the diaphragm (57+/-8 s), and the adductor pollicis (54+/-13 s), after succinylcholine (all mean +/- SD). After rocuronium, onset time was 124+/-39 s at the larynx, 130+/-44 s at the diaphragm, and 115+/-21 s at the adductor pollicis. After succinylcholine administration, time to 90% recovery was 8.3+/-3.2, 7.2+/-3.5, and 9.1+/-3.0 min at the larynx, the diaphragm, and the adductor pollicis, respectively. Time to 90% recovery after rocuronium administration was 34.9+/-7.6, 30.4+/-4.2, and 49.1+/-11.4 min at the larynx, the diaphragm, and the adductor pollicis, respectively. Conclusion Neuromuscular blocking effect of muscle relaxants on the larynx can be measured noninvasively by electromyography. Although the larynx appears to be resistant to muscle relaxants, we could not demonstrate that its onset time differed from that of peripheral muscles.

Drawing Distinctions Among Different Types of Research on Persons with Autism

2019 ◽  
pp. 229-232
Author(s):  
Deborah R. Barnbaum
Keyword(s):  
Informed Consent ◽  
Different Types ◽  
Made In

This commentary engages two aspects of Kenneth A. Richman’s chapter “Autism, Autonomy, and Research” (Chapter 5). First, several excellent points made in the chapter are discussed. Second, a distinction is introduced among types of research on persons with autism, a distinction that would strengthen his discussion. Drawing distinctions among the ways in which informed consent is confounded by symptoms of autism, as well as among types of research on autism, would further strengthen an already compelling chapter.

scholarly journals VLF surface-impedance measurements for ice-depth mapping — an assessment of some commonly encountered interference effects

1996 ◽  
Vol 42 (140) ◽  
pp. 33-36 ◽  
Author(s):  
David V. Thiel ◽  
Daniel James ◽  
Peter Johnson
Keyword(s):  
Surface Impedance ◽  
Apparent Resistivity ◽  
Low Frequency ◽  
Two Dimensional ◽  
Interference Effects ◽  
Impedance Measurements ◽  
Very Low Frequency ◽  
Dimensional Boundary ◽  
Lateral Variations ◽  
Made In

AbstractThe effects on very low-frequency surface-impedence measurements of lateral variations commonly found in ice environments have been measured and modelled numerically using die quasi-static two-dimensional boundary-element method. Results indicate that surface-impedance measurements made in the vicinity of crevasses oriented perpendicular to the plane Of incidence, and those made in the vicinity of moraines and melt streams, can all show significant changes to the measured apparent resistivity. It is, therefore, misleading to use such measurements in the interpretation of ice depth.

scholarly journals Obtenção de Consentimento Informado para Anestesia em Cirurgia Eletiva num Hospital Terciário: Práticas e Contexto Ético-Legal

2019 ◽  
Vol 32 (1) ◽  
pp. 53
Author(s):  
Luís Guilherme Casimiro ◽  
Sara Marisa Pereira ◽  
Sofia Cardoso Pires ◽  
Joana Mourão
Keyword(s):  
Informed Consent ◽  
Elective Surgery ◽  
University Hospital ◽  
Anesthetic Technique ◽  
Patient Relationship ◽  
Active Process ◽  
Legal Principles ◽  
American Society ◽  
American Society Of Anesthesiologists ◽  
Written Informed Consent

Introduction: Informed consent is an active process of the doctor-patient relationship, based on ethical and legal principles. The anesthetic act has inherent risks, which should be subject of specific consent. The aim of this study was to evaluate the degree of implementation of written specific informed consent for anesthesia in the context of elective surgery.Material and Methods: An observational prospective study, at a tertiary university hospital, in 230 patients aged 60 years or older, undergoing elective surgery between May and July 2017. Eligible patients who consented to participate were interviewed clinically on the day before surgery. In the postoperative period, the anesthetic technique and the existence of the written informed consent for the anesthetic and surgical procedures were assessed. Patients who were unable to give informed consent or those admitted in the Intensive Care Unit after surgery were excluded. Results: Written informed consent for the surgical procedure was obtained for 225 (97.8%), while it was obtained in just 96 (41.7%) patients for the anesthetic act. There was a higher prevalence of stroke, anemia, and higher Charlson and physical American Society of Anesthesiologists scores in patients without written informed consent for the anesthetic act.Discussion: We identified a low implementation of written informed consent for anesthesia. This situation may have important implications in the context of disciplinary, civil or criminal liability.Conclusion: Despite its importance, the practice of written informed consent for anesthesia in this institution is not yet implemented on a regular basis.

scholarly journals Observation of Global 160-min Infrared (Differential) Intensity Variation of the Sun

1983 ◽  
Vol 66 ◽  
pp. 21-35
Author(s):  
V.A. Kotov ◽  
S. Koutchmy ◽  
O. Koutchmy
Keyword(s):  
Low Frequency ◽  
Intensity Variation ◽  
Solar Limb ◽  
The Sun ◽  
Average Amplitude ◽  
Instrument Analysis ◽  
Limb Intensity ◽  
Limb Darkening ◽  
Global Fluctuations ◽  
Made In

AbstractThe method developed and the instrument designed for detecting variations of the solar limb darkening at the atmospheric transparency window of the solar opacity minimum region of λ 1.65 µ are described. This differential technique proved to be successful in rejecting undesirable low frequency noises due to the atmosphere and to the instrument. Analysis of observations made in 1977, 1978, and 1981 indicates the persistance of global fluctuations of the IR differential, center-to-limb intensity at the wellknown 160 min period with an average amplitude of about ± 2 x 10-4 in units of the ‘average Sun’ intensity near 1.65 µm.

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