On-line Monitoring of End-tidal Propofol Concentration in Anesthetized Patients

Background Propofol (2,6-diisopropylphenol) has some volatility, so it can be detected in expired breath of individuals receiving intravenous propofol. This study measured volatile propofol exhaled by patients and investigated the relation between exhaled and plasma propofol concentrations. Methods Nineteen patients with American Society of Anesthesiologists physical status I or II who were undergoing elective surgery participated in this two-part study. In study 1 (n = 11), anesthesia was induced with 2 mg/kg propofol, 0.1 mg/kg vecuronium, and 2 microg/kg fentanyl. After intubation, propofol was administered continuously for 60 min at each of three rates: 3, 6, and 9 mg x kg(-1) x h(-1). Blood samples were obtained just before each change in the infusion rate, and the plasma concentrations of propofol were measured. The exhaled propofol concentration was measured continuously by means of proton transfer mass spectrometry. End-tidal propofol concentrations during blood sampling were averaged and compared with plasma propofol concentrations. In study 2 (n = 8), after induction of anesthesia, patients received a bolus injection of 2 mg/kg propofol, and the exhaled propofol concentration was measured. Results Volatile propofol was detected in expired gas from all study patients. From study 1, the authors obtained 24 paired data points, i.e., concentrations of end-tidal and plasma propofol. With Bland-Altman analysis, bias +/- precision was 5.2 +/- 10.4 with 95% limits of agreement of -15.1 and 25.6. In study 2, the exhaled propofol concentration curve showed an obvious peak in all patients. Conclusions Agreement between plasma and exhaled propofol concentrations suggests that proton transfer mass spectrometry can be used for real-time propofol monitoring.

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The Combitube in Elective Surgery

Anesthesiology ◽

10.1097/00000542-200101000-00016 ◽

2001 ◽

Vol 94 (1) ◽

pp. 79-82 ◽

Cited By ~ 49

Author(s):

Luis A. Gaitini ◽

Sonia J. Vaida ◽

Somri Mostafa ◽

Boris Yanovski ◽

Milian Croitoru ◽

...

Keyword(s):

Elective Surgery ◽

Airway Device ◽

Spontaneous Ventilation ◽

Mechanically Ventilated ◽

Entire Duration ◽

Duration Of Surgery ◽

American Society ◽

End Tidal ◽

American Society Of Anesthesiologists ◽

Spontaneously Breathing

Background The Combitube has proved to be a valuable device for securing the airway in cases of difficult intubation. This study investigated the effectiveness of the Combitube in elective surgery during both mechanical and spontaneous ventilation. Methods Two hundred patients classified as American Society of Anesthesiologists physical status I and II, with normal airways, scheduled for elective surgery were randomly allocated into two groups: nonparalyzed, spontaneously breathing (n = 100); or paralyzed, mechanically ventilated (n = 100). After induction of general anesthesia and insertion of the Combitube, oxygen saturation, end-tidal carbon dioxide and isoflurane concentration, systolic and diastolic blood pressure and heart rate, as well as breath-by-breath spirometry data were obtained every 5 min. Results In 97% of patients, it was possible to maintain oxygenation, ventilation, and respiratory mechanics, as well as hemodynamic stability during either mechanical or spontaneous ventilation for the entire duration of surgery. The duration of surgery was between 15 and 155 min. Conclusions The results of this study suggest that the Combitube is an effective and safe airway device for continued management of the airway in 97% of elective surgery cases.

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Comparative Hemodynamic Depression of Sevoflurane versus Halothane in Infants

Anesthesiology ◽

10.1097/00000542-199710000-00012 ◽

1997 ◽

Vol 87 (4) ◽

pp. 795-800 ◽

Cited By ~ 102

Author(s):

Eric Wodey ◽

Patrick Pladys ◽

Catherine Copin ◽

Marie Madeleine Lucas ◽

Andre Chaumont ◽

...

Keyword(s):

Heart Rate ◽

Cardiac Index ◽

Elective Surgery ◽

Physical Status ◽

Inhalation Induction ◽

Cardiovascular Side Effects ◽

American Society ◽

End Tidal ◽

American Society Of Anesthesiologists ◽

To Receive

Background The cardiovascular side effects of volatile anesthetics are one of the chief causes of postoperative complications in children, and infants seem to be at the greatest risk for this. This study compared cardiovascular changes at equipotent concentrations of sevoflurane and halothane in infants. Methods Thirty infants classified as American Society of Anesthesiologists physical status I or II who required elective surgery were randomized to receive either halothane or sevoflurane for inhalation induction. Cardiovascular and echocardiographic data were recorded in both groups at baseline and at end-tidal concentrations of 1 and 1.5 minimum alveolar concentration (MAC). Results Sevoflurane did not alter heart rate or cardiac index at all concentrations compared with awake values. Sevoflurane significantly decreased blood pressure and systemic vascular resistance compared with awake values at all concentrations. Shortening fraction and rate-corrected velocity of circumferential fiber shortening decreased at 1.5 but not at 1 MAC. Myocardial contractility assessed by stress-velocity index and stress-shortening index decreased significantly at all concentrations, but did not fall into the abnormal range at any concentration. Halothane caused a greater decrease in heart rate, shortening fraction, stress-shortening index, velocity of circumferential fiber shortening, stress-velocity index, and cardiac index at all concentrations than did sevoflurane. Conclusion Sevoflurane causes a lesser decrease in cardiac output than does halothane in infants.

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Augmentation of the Rocuronium-induced Neuromuscular Block by the Acutely Administered Phenytoin

Anesthesiology ◽

10.1097/00000542-199906000-00009 ◽

1999 ◽

Vol 90 (6) ◽

pp. 1551-1555. ◽

Cited By ~ 19

Author(s):

Anna Spacek ◽

Stephan Nickl ◽

Franz X. Neiger ◽

Vladimir Nigrovic ◽

Odo-Winfried Ullrich ◽

...

Keyword(s):

Plasma Proteins ◽

Neuromuscular Block ◽

Plasma Concentrations ◽

Acute Administration ◽

Arterial Blood ◽

Evoked Electromyography ◽

American Society ◽

Neuromuscular Transmission Monitor ◽

End Tidal ◽

American Society Of Anesthesiologists

Background The effects of an acute administration of phenytoin on the magnitude of the rocuronium-induced neuromuscular block were evaluated. Methods Twenty patients (classified as American Society of Anesthesiologists physical status I or II) scheduled for craniotomy were studied: 15 received phenytoin during operation (10 mg/kg), and the others served as controls. Anesthesia was induced with thiopental and fentanyl and maintained with nitrous oxide (65%) in oxygen and end-tidal isoflurane (1%). The ulnar nerve was stimulated supramaximally and the evoked electromyography was recorded using a neuromuscular transmission monitor. Continuous infusion of rocuronium maintained the neuromuscular block with first twitch (T1) between 10 and 15% for 45 min before the start of an infusion of either phenytoin or NaCl 0.9%. Twitch recordings continued for 60 min thereafter. Arterial blood samples were collected at the predefined time points (four measurements before and four after the start of the infusion) to determine the concentrations of phenytoin and rocuronium and the percentage of rocuronium bound to plasma proteins. Results The first twitch produced by an infusion of rocuronium remained constant during the 15 min before and the 60 min after the start of the saline infusion. After the phenytoin infusion, the twitch decreased progressively, but the plasma concentrations and the protein-bound fraction of rocuronium did not change. Conclusion Phenytoin acutely augments the neuromuscular block produced by rocuronium without altering its plasma concentration or its binding to plasma proteins.

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Proton Transfer Reaction-Mass Spectrometry for On-line Analysis of Trace Volatile Organic Compounds

CHINESE JOURNAL OF ANALYTICAL CHEMISTRY (CHINESE VERSION) ◽

10.3724/sp.j.1096.2011.01611 ◽

2012 ◽

Vol 39 (10) ◽

pp. 1611-1618

Author(s):

Xue-Fang ZHAN ◽

Yi-Xiang DUAN

Keyword(s):

Mass Spectrometry ◽

Volatile Organic Compounds ◽

Proton Transfer ◽

Organic Compounds ◽

Transfer Reaction ◽

Proton Transfer Reaction ◽

Reaction Mass ◽

Volatile Organic ◽

On Line ◽

Line Analysis

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Comparison of Train of Four Measurements with Kinemyography NMT DATEX and Accelerography TOFscan

Medical Sciences ◽

10.3390/medsci9020021 ◽

2021 ◽

Vol 9 (2) ◽

pp. 21

Author(s):

Cyrus Motamed ◽

Migena Demiri ◽

Nora Colegrave

Keyword(s):

Neuromuscular Blockade ◽

Lower Limit ◽

Elective Surgery ◽

Orotracheal Intubation ◽

Neuromuscular Blocking ◽

Physical Status Classification ◽

Train Of Four ◽

Surgery First ◽

American Society ◽

American Society Of Anesthesiologists

Introduction: This study was designed to compare the Datex neuromuscular transmission (NMT) kinemyography (NMTK) device with the TOFscan (TS) accelerometer during the onset and recovery of neuromuscular blockade. Patients and methods: This prospective study included adult patients who were scheduled to undergo elective surgery with general anesthesia and orotracheal intubation. The TS accelerometer was randomly placed at the adductor pollicis on one hand, and the NMTK was placed on the opposite arm. Anesthesia was initiated with remifentanil target-controlled infusion (TCI) and 2.0–3.0 mg/kg of propofol. Thereafter, 0.5 mg/kg of atracurium or 0.6 mg/kg of rocuronium was injected. If needed, additional neuromuscular blocking agents were administered to facilitate surgery. First, we recorded the train of four (TOF) response at the onset of neuromuscular blockade to reach a TOF count of 0. Second, we recorded the TOF response at the recovery of neuromuscular blockade to obtain a T4/T1 90% by both TS and NMTK. Results: There were 32 patients, aged 38–83 years, with the American Society of Anesthesiologists (ASA) Physical Status Classification I–III included and analyzed. Surgery was abdominal, gynecologic, or head and neck. The Bland and Altman analysis for obtaining zero responses during the onset showed a bias (mean) of 2.7 s (delay) of TS in comparison to NMTK, with an upper/lower limit of agreement of [104; −109 s] and a bias of 36 s of TS in comparison to NMTK, with an upper/lower limit of agreement of [−21.8, −23.1 min] during recovery (T4/T1 > 90%). Conclusions: Under the conditions of the present study, the two devices are not interchangeable. Clinical decisions for deep neuromuscular blockade should be made cautiously, as both devices appear less accurate with significant variability.

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