Anesthetic Techniques

Anesthetic techniques for procedures performed outside the traditional operating room are varied. General anesthesia, sedation, and regional anesthesia can all be delivered in this venue. The choice of technique is based on safety considerations and patient comorbidities. Perioperative monitoring such as pulse oximetry, end-tidal carbon dioxide monitoring, and electrocardiography and blood pressure monitoring protocols must be consistent with American Society of Anesthesiologists guidelines. Common procedures include elective office-based anesthetics, emergency room sedations, endoscopic retrograde cholangiopancreatographies in the gastroenterology suite, and minimally invasive interventions in the radiology department. Because most of these locations have limited postanesthesia care unit capabilities, the patient’s rapid return to baseline functioning and the ability to be discharged quickly, safely, and comfortably are important goals. Thus, anesthetic technique and the pharmacokinetics and pharmacodynamics of the anesthetics, analgesics, antiemetics, and local anesthetics are of utmost importance.

Anesthetic Techniques

Anesthesia Outside of the Operating Room ◽

10.1093/med/9780195396676.003.0004 ◽

2011 ◽

pp. 28-36

Author(s):

Laurence M. Hausman ◽

Meg A. Rosenblatt

Keyword(s):

Anesthesia Machine ◽

Radiology Department ◽

Postanesthesia Care Unit ◽

Anesthetic Techniques ◽

Elective Office ◽

Emergency Interventions ◽

American Society ◽

The Many ◽

Safety Considerations ◽

Anesthetic techniques for procedures performed outside the traditional operating room (OOOR) are as varied as the surgeries themselves and wholly dependent upon the equipment available at each specific location as well as any patient comorbidities that may exist. General anesthesia (GA) may be delivered with or without an anesthesia machine, monitored anesthesia care (MAC) with or without infusion pumps, and regional anesthesia (RA) with or without a nerve stimulator (NS) or ultrasound (US). Whatever technique is chosen, safety considerations are paramount and perioperative monitoring must always be consistent with American Society of Anesthesiologists (ASA) guidelines (see Appendix for a list of useful ASA documents). OOOR procedures are widely varied and include elective office-based anesthetics and emergency room ones, endoscopic retrograde cholangiopancreatographies (ERCPs) in the gastroenterology suite, and emergency interventions in the invasive radiology department. Most of these locations have limited postanesthesia care unit (PACU) capabilities, so both rapid return to baseline functioning and the ability to discharge a comfortable patient are important goals with rare exceptions that will be discussed. This chapter will focus on the many anesthetic options available to the OOOR anesthesiology practitioner.

Surgeon-administered Conscious Sedation and Local Anesthesia for Ambulatory Anorectal Surgery

The American Surgeon ◽

10.1177/000313481408000114 ◽

2014 ◽

Vol 80 (1) ◽

pp. 21-25 ◽

Cited By ~ 4

Author(s):

Miss Hina ◽

Jon S. Hourigan ◽

Richard A. Moore ◽

J. Daniel Stanley

Keyword(s):

Local Anesthesia ◽

Conscious Sedation ◽

Outpatient Surgery ◽

Outpatient Setting ◽

Postanesthesia Care Unit ◽

Anesthetic Techniques ◽

Anorectal Surgery ◽

Degree Of Satisfaction ◽

American Society ◽

Anorectal procedures are often performed in an outpatient setting using a variety of anesthetic techniques. One technique that has not been well studied is surgeon-administered conscious sedation along with local anesthetic. The purpose of this study was to evaluate the use of this technique with emphasis on safety, efficacy, and patient satisfaction. Chart review was performed on 133 consecutive patients who had anorectal procedures at an outpatient surgery center. Additionally, 65 patients were enrolled prospectively and completed a satisfaction survey. Inclusively, charts of 198 patients who underwent outpatient anorectal surgery under conscious sedation and local anesthesia under the direction of a colorectal surgeon from 2004 through 2008 were reviewed. Parameters related to patient and procedural characteristics, safety, efficacy, and satisfaction were evaluated. Surgeon-administered sedation consisted of combined fentanyl and midazolam in 90 per cent. Eighty per cent of procedures were performed in the prone position and 23 per cent were in combination with an endoscopic procedure. Eighty-two per cent were classified as American Society of Anesthesiologists Grade 1 or 2. Transient mild hypoxemia or hypotension occurred in 4 and 3 per cent of the patients, respectively. Mean operative time was 29 minutes with a mean stay in the postanesthesia care unit of 37 minutes. There were no early major cardiac or respiratory complications. Ninety-seven per cent of the patients surveyed reported a high degree of satisfaction. Surgeon-administered conscious sedation with local anesthesia was well tolerated for outpatient anorectal surgeries. Additional studies are needed to confirm the safety and efficacy of this technique.

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

Acta Médica Portuguesa ◽

10.20344/amp.10592 ◽

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 ◽

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.

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 ◽

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.

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

Anesthesiology ◽

10.1097/01.anes.0000264745.63275.59 ◽

2007 ◽

Vol 106 (4) ◽

pp. 659-664 ◽

Cited By ~ 94

Author(s):

Akira Takita ◽

Kenichi Masui ◽

Tomiei Kazama

Keyword(s):

Mass Spectrometry ◽

Proton Transfer ◽

Elective Surgery ◽

Plasma Concentrations ◽

Paired Data ◽

Data Points ◽

On Line ◽

American Society ◽

End Tidal ◽

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.

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 ◽

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.

Evaluation of Differences between PaCO2 and ETCO2 by Age as Measured during General Anesthesia with Patients in a Supine Position

Journal of Anesthesiology ◽

10.1155/2015/710537 ◽

2015 ◽

Vol 2015 ◽

pp. 1-5

Author(s):

Kenichi Satoh ◽

Ayako Ohashi ◽

Miho Kumagai ◽

Masahito Sato ◽

Akiyoshi Kuji ◽

...

Keyword(s):

Carbon Dioxide ◽

Pressure Gradient ◽

Partial Pressure ◽

General Anesthesia ◽

Supine Position ◽

Physical Status ◽

American Society ◽

End Tidal ◽

Objective. The aim of this study was to evaluate the arterial to end-tidal partial pressure gradient of carbon dioxide according to age in the supine position during general anesthesia. Methods. From January 2001 to December 2013, we evaluated 596 patients aged ≥16 years who underwent general anesthesia in the supine position. The anesthetic charts of these 596 patients, all classified as American Society of Anesthesiologists physical status I or II, were retrospectively reviewed to investigate the accuracy of PaCO2 and ETCO2. Results. The a-ETCO2 was 3.0 ± 2.1 mmHg for patients aged 16 to <65 years and 4.1±3.1 mmHg for patients ≥65 years. The a-ETCO2 was 2.4±3.1 mmHg for patients aged 16 to 25 years, 3.1±2.2 mmHg for patients aged 26 to 35 years, 3.0±2.2 mmHg for patients aged 36 to 45 years, 3.4±2.0 mmHg for patients aged 46 to 55 years, 3.2±2.0 mmHg for patients aged 56 to 64 years, 4.3±3.2 mmHg for patients aged 65 to 74 years, and 3.7±2.8 mmHg for patients aged 75 to 84 years. Conclusion. The arterial to end-tidal partial pressure gradient of carbon dioxide tended to increase with increasing age.

Changes of Electroencephalographic Bicoherence during Isoflurane Anesthesia Combined with Epidural Anesthesia

Anesthesiology ◽

10.1097/00000542-200212000-00012 ◽

2002 ◽

Vol 97 (6) ◽

pp. 1409-1415 ◽

Cited By ~ 30

Author(s):

Satoshi Hagihira ◽

Masaki Takashina ◽

Takahiko Mori ◽

Takashi Mashimo ◽

Ikuto Yoshiya

Keyword(s):

Epidural Anesthesia ◽

Physical Status ◽

Isoflurane Concentration ◽

Frequency Space ◽

Isoflurane Anesthesia ◽

Restricted Region ◽

American Society ◽

End Tidal ◽

Two Peaks

Background The authors previously reported that, during isoflurane anesthesia, electroencephalographic bicoherence values changed in a fairly restricted region of frequency versus frequency space. The aim of the current study was to clarify the relation between electroencephalographic bicoherence and the isoflurane concentration. Methods Thirty elective abdominal surgery patients (male and female, aged 34-77 yr, American Society of Anesthesiologists physical status I-II) were enrolled. After electroencephalogram recording with patients in an awake state, anesthesia was induced with 3 mg/kg thiopental and maintained with oxygen and isoflurane. Continuous epidural anesthesia with 80-100 mg/kg 1% lidocaine was also administered. Using software they developed, the authors continuously recorded the FP1-A1 lead of the electroencephalographic signal and expired isoflurane concentration to an IBM-PC compatible computer. After confirming the steady state of each isoflurane (end-tidal concentration at 0.3, 0.5, 0.7, 0.9, 1.1, 1.3, and 1.5%), electroencephalographic bicoherence values were calculated. Results In a light anesthetic state, electroencephalographic bicoherence values were low (generally < or = 15.0%). At increased concentrations of isoflurane, two peaks of electroencephalographic bicoherence emerged along the diagonal line (f1=f2). The peak emerged at around 4.0 Hz and grew higher as isoflurane concentration increased until it reached a plateau (43.8 +/- 3.5%, mean +/- SD) at isoflurane 0.9%. The other peak, at about 10.0 Hz, also became significantly higher and reached a plateau (32.6 +/- 9.2%) at isoflurane 0.9%; at isoflurane 1.3%, however, this peak slightly decreased. Conclusion Changes in the height of two electroencephalographic bicoherence peaks correlated well with isoflurane concentration.

Incidence of Airway Complications Associated with Deep Extubation in Adults

10.21203/rs.3.rs-52114/v2 ◽

2020 ◽

Author(s):

Jeremy Juang ◽

Martha Cordoba ◽

Alex Ciaramella ◽

Mark Xiao ◽

Jeremy Goldfarb ◽

...

Keyword(s):

Prospective Observational Study ◽

Important Determinant ◽

Physical Status ◽

Respiratory Complications ◽

Airway Assessment ◽

Eye Opening ◽

American Society ◽

End Tidal ◽

Endotracheal Extubation

Abstract Background: Endotracheal extubation is the most crucial step during emergence from general anesthesia and is usually carried out when patients are awake with return of airway reflexes. Alternatively, extubations can also be accomplished while patients are deeply anesthetized, a technique known as “deep extubation”, in order to provide a “smooth” emergence from anesthesia. Deep extubation is seldomly performed in adults, even in appropriate circumstances, likely due to concerns for potential respiratory complications and limited research supporting its safety. It is in this context that we designed our prospective study to understand the factors that contribute to the success or failure of deep extubation in adults. Methods: In this prospective observational study, 300 patients, age ≥ 18, American Society of Anesthesiologists Physical Status (ASA PS) Classification I - III, who underwent head-and-neck and ocular surgeries. Patients’ demographic, comorbidity, airway assessment, O2 saturation, end tidal CO2 levels, time to exit OR, time to eye opening, and respiratory complications after deep extubation in the OR were analyzed. Results: Forty (13%) out of 300 patients had at least one complication in the OR, as defined by persistent coughing, desaturation SpO2 < 90% for longer than 10s, laryngospasm, stridor, bronchospasm and reintubation. When comparing the complication group to the no complication group, the patients in the complication group had significantly higher BMI (30 vs 26), lower O2 saturation pre and post extubation, and longer time from end of surgery to out of OR (p<0.05). Conclusions: The complication rate during deep extubation in adults was relatively low compared to published reports in the literature and all easily reversible. BMI is possibly an important determinant in the success of deep extubation.

Association of Ethnicity with the Minimum Alveolar Concentration of Sevoflurane

Anesthesiology ◽

10.1097/01.anes.0000267534.31668.62 ◽

2007 ◽

Vol 107 (1) ◽

pp. 9-14 ◽

Cited By ~ 19

Author(s):

Tiberiu Ezri ◽

Daniel Sessler ◽

Marian Weisenberg ◽

Gleb Muzikant ◽

Michael Protianov ◽

...

Keyword(s):

Selective Breeding ◽

Minimum Alveolar Concentration ◽

Skin Incision ◽

Physical Status ◽

The Caucasus ◽

Lifestyle Choices ◽

American Society ◽

End Tidal ◽

Animal Strains

Abstract Background: Selective breeding produces animal strains with varying anesthetic sensitivity. It thus seems unlikely that various human ethnicities have identical anesthetic requirements. Therefore, the authors tested the hypothesis that the minimum alveolar concentration of sevoflurane differs significantly as a function of ethnicity. Methods: The authors recruited 90 American Society of Anesthesiologists physical status I and II adult patients belonging to three Jewish ethnic groups: European, Oriental, and Caucasian (from the Caucasus Mountain region). All were scheduled to undergo surgery requiring a skin incision exceeding 3 cm. Without premedication, anesthesia was induced with 6–8% sevoflurane in 100% oxygen, and tracheal intubation was facilitated with succinylcholine. The skin incision was made after a predetermined end-tidal concentration of sevoflurane of 2.0% was maintained for at least 10 min in the first patient in each group. Blinded investigators observed the patient for movement during the subsequent minute. The concentration in the next patient was increased by 0.2% when patients moved, or decreased by the same amount when they did not. Results are presented as means [95% confidence intervals]. Results: Morphometric and demographic characteristics were similar among the groups; however, mean arterial pressure was slightly greater in European Jews. Minimum alveolar concentration for sevoflurane was greatest in Caucasian Jews (2.32% [2.27–2.41%]), less in Oriental Jews (2.14% [2.06–2.22%]), and still less in European Jews (1.9% [1.82–1.99%]) (P < 0.001). Conclusions: The results suggest that minimum alveolar concentration varies as a function of ethnicity. However, the extent to which confounding characteristics contribute, including lifestyle choices and environmental factors, remains unknown.