2020 AAHA Anesthesia and Monitoring Guidelines for Dogs and Cats*

VETERINARY PRACTICE GUIDELINES 2020 AAHA Anesthesia and Monitoring Guidelines for Dogs and Cats* Tamara Grubb, DVM, PhD, DACVAAy, Jennifer Sager, BS, CVT, VTS (Anesthesia/Analgesia, ECC)y, James S. Gaynor, DVM, MS, DACVAA, DAIPM, CVA, CVPP, Elizabeth Montgomery, DVM, MPH, Judith A. Parker, DVM, DABVP, Heidi Shafford, DVM, PhD, DACVAA, Caitlin Tearney, DVM, DACVAA ABSTRACT Risk for complications and even death is inherent to anesthesia. However, the use of guidelines, checklists, and training can decrease the risk of anesthesia-related adverse events. These tools should be used not only during the time the patient is unconscious but also before and after this phase. The framework for safe anesthesia delivered as a continuum of care from home to hospital and back to home is presented in these guidelines. The critical importance of client commu- nication and staff training have been highlighted. The role of perioperative analgesia, anxiolytics, and proper handling of fractious/fearful/aggressive patients as components of anesthetic safety are stressed. Anesthesia equipment selection and care is detailed. The objective of these guidelines is to make the anesthesia period as safe as possible for dogs and cats while providing a practical framework for delivering anesthesia care. To meet this goal, tables, algorithms, figures, and “tip” boxes with critical information are included in the manuscript and an in-depth online resource center is available at aaha.org/anesthesia. (J Am Anim Hosp Assoc 2020; 56:---–---. DOI 10.5326/JAAHA-MS-7055) AFFILIATIONS Other recommendations are based on practical clinical experience and From Washington State University College of Veterinary Medicine, Pullman, a consensus of expert opinion. Further research is needed to document Washington (T.G.); University of Florida Veterinary Hospitals, Gainesville, some of these recommendations. Because each case is different, vet- Florida (J.S.); Peak Performance Veterinary Group, Breckenridge, Colorado erinarians must base their decisions on the best available scientific ev- (J.S.G.); University of California, Davis, School of Veterinary Medicine, Davis, idence in conjunction with their own knowledge and experience. California (E.M.); Pima Pet Clinic, Tucson, Arizona (J.A.P.); Veterinary An- Note: When selecting products, veterinarians have a choice among esthesia Specialists, Clackamas, Oregon (H.S.); and Wheat Ridge Animal those formulated for humans and those developed and approved by Hospital, Wheat Ridge, Colorado (C.T.). veterinary use. Manufacturers of veterinary-specific products spend CONTRIBUTING REVIEWERS resources to have their products reviewed and approved by the FDA for Ralph Harvey, DVM, MS, DACVAA (Small Animal Clinical Sciences [Re- canine or feline use. These products are specifically designed and for- tired], College of Veterinary Medicine, University of Tennessee, Knoxville, mulated for dogs and cats and have benefits for their use; they are not TN); David D. Martin, DVM, DACVAA (Private consultant, Kalamazoo, MI). human generic products. AAHA suggests that veterinary professionals make every effort to use veterinary FDA-approved products and base Correspondence: [email protected] (T.G.); sagerj@ufl.edu (J.S.) their inventory-purchasing decisions on what product is most beneficial *These guidelines are supported by generous educational grants from to the patient. IDEXX Laboratories, Inc., Midmark, and Zoetis Petcare. They were AAFP (American Association of Feline Practitioners); ASA (American subjected to a formal peer-review process. Society of Anesthesiologists); BP (blood pressure); CRI (continuous rate † T. Grubb and J. Sager were cochairs of the Anesthesia and Monitoring infusion); ECG (electrocardiogram); ETCO2 (end-tidal carbon dioxide); task force. ETT (endotracheal tube); GER (gastroesophageal reflux); HR (heart rate); IM (intramuscular); NSAID (nonsteroidal anti-inflammatory drug); NRC These guidelines were prepared by a Task Force of experts convened (nonrebreathing circuit); PPV (positive pressure ventilation); RC (rebreath- by the American Animal Hospital Association. This document is inten- ing circuit); RR (respiratory rate); SpO (percentage of hemoglobin sat- ded as a guideline only, not an AAHA standard of care. These guidelines 2 urated with oxygen) and recommendations should not be construed as dictating an exclu- sive protocol, course of treatment, or procedure. Variations in practice may be warranted based on the needs of the individual patient, re- sources, and limitations unique to each individual practice setting. Evidence-based support for specific recommendations has been cited whenever possible and appropriate. ª 2020 by American Animal Hospital Association JAAHA.ORG 1 Introduction components to be particularly useful. Algorithms, figures, “tips” The statement “there are no safe anesthetic agents, there are no safe boxes, and tables provide quick access to the essential resources and anesthetic procedures, there are only safe anesthetists” should be the methods associated with anesthesia. An online resources center dictum for the entire anesthetic process in every practice.1 The (aaha.org/anesthesia) is also available for more detailed information. anesthesia team has the crucial role of identifying patient comor- bidities and procedure risks and minimizing the detrimental effects Phase 1: Preanesthesia of perioperative pain and stress in order to provide safe and effi- Individualized Anesthetic/Analgesic Plan and cacious anesthesia for each patient. In addition, “anesthesia” is not Client Communication limited to the period when the patient is unconscious but is a An individualized anesthetic plan with specific and sequential steps continuum of care that begins before the patient leaves home and ensures the continuum of care throughout the entire anesthetic ends when the patient is returned home with appropriate physio- process. A complete anesthetic plan must address all phases of an- logic function and absent or minimal pain levels. At home, the esthesia, with inclusion of perioperative analgesia throughout each continuum begins with the pet owner administering prophylactic phase. Although each patient should be treated as an individual, drugs like analgesics and anxiolytics as well as fasting the pet. In the having a set of anesthesia plans that are used repeatedly is appro- hospital, the anesthesia continuum includes all of the following four priate. This allows the anesthesia team a level of comfort with their phases of anesthesia: preanesthesia, induction, maintenance, and anesthesia protocols while adjusting plans based on individual pa- recovery. Anesthesia starts with a preanesthetic evaluation and sta- tient needs. bilization (if necessary) of the patient, preparation of all of the The preanesthesia phase includes not only the choice of anesthetic equipment, and selection of appropriate drugs with preanesthetic sedatives and analgesics but also a full preanesthetic precise calculation of drug dosages for all phases of anesthesia. In- evaluation and stabilization of the patient, if necessary. Categori- duction and careful intubation followed by intraoperative moni- zation of patients using the American Society of Anesthesiologists toring and physiologic support in the maintenance phase are the (ASA) Patient Status Scale (scoring of 1–5) provides a framework next steps, with continued monitoring and support into the re- for evaluation of patient health and determination of stabilization covery phase. Postanesthesia care, as communicated by the veteri- requirements prior to anesthesia (available at aaha.org/anesthesia). nary staff with the pet owner in the clinic and at home, completes An increase in ASA status from 1 or 2 to 3, or from 3 to 4 or 5, the continuum. Provision of analgesia and client/staff communica- increased the odds of anesthesia-related death in dogs and cats.4 tion and education are critical throughout the entire process. In another study, an ASA status of $3 increased the odds of The objective of these guidelines is to make the anesthesia anesthesia-related death when compared with an ASA status period as safe as possible for dogs and cats while providing a practical of #2, with cats having a higher odds ratio than dogs for anes- framework for delivering anesthesia care before, during, and after the thetic death.4,5 anesthetic procedure. The guidelines are intended to be compre- Risks specific to the patient’s size and age and the surgical or hensive but neither all-inclusive nor a single source for information medical procedure need to be considered.4–6 Disease-related risks and clinical recommendations. More detailed references are available should be corrected or minimized if possible (see textbox “Potential for pain management2 and cat-specific anesthetic and analgesic Anesthesia Risk Factors and Actions to Mitigate Risk”).6–8 needs,3 and academic anesthesia textbooks address disease-, breed-, Monitoring of physiologic parameters and provision of physi- and procedure-specific anesthesia recommendations and outcomes. ologic support are integral to the plan in order to reduce the like- However, the guidelines are designed to be as actionable as pos- lihood of adverse events.4–6 Also critical is a plan for anesthetic sible. With that in mind, readers will find the guidelines’ visual recovery and for postdischarge care.4–6 Resources such as staffing, Recommended Resources Related Resources 2015 AAHA/AAFP Pain Management Guidelines for Dogs and Cats (aaha.org/pain- 2015 AAHA Canine and Feline Behavior

Artificial Intelligence in Health Care: The Hope, the Hype, the Promise, the Peril Michael Matheny, Sonoo Thadaney Israni, Mahnoor Ahmed, and Danielle Whicher, Editors WASHINGTON, DC NAM.EDU PREPUBLICATION COPY - Uncorrected Proofs NATIONAL ACADEMY OF MEDICINE • 500 Fifth Street, NW • WASHINGTON, DC 20001 NOTICE: This publication has undergone peer review according to procedures established by the National Academy of Medicine (NAM). Publication by the NAM worthy of public attention, but does not constitute endorsement of conclusions and recommendationssignifies that it is the by productthe NAM. of The a carefully views presented considered in processthis publication and is a contributionare those of individual contributors and do not represent formal consensus positions of the authors’ organizations; the NAM; or the National Academies of Sciences, Engineering, and Medicine. Library of Congress Cataloging-in-Publication Data to Come Copyright 2019 by the National Academy of Sciences. All rights reserved. Printed in the United States of America. Suggested citation: Matheny, M., S. Thadaney Israni, M. Ahmed, and D. Whicher, Editors. 2019. Artificial Intelligence in Health Care: The Hope, the Hype, the Promise, the Peril. NAM Special Publication. Washington, DC: National Academy of Medicine. PREPUBLICATION COPY - Uncorrected Proofs “Knowing is not enough; we must apply. Willing is not enough; we must do.” --GOETHE PREPUBLICATION COPY - Uncorrected Proofs ABOUT THE NATIONAL ACADEMY OF MEDICINE The National Academy of Medicine is one of three Academies constituting the Nation- al Academies of Sciences, Engineering, and Medicine (the National Academies). The Na- tional Academies provide independent, objective analysis and advice to the nation and conduct other activities to solve complex problems and inform public policy decisions.

17 Patient-Monitoring Systems REED M. GARDNER AND M. MICHAEL SHABOT After reading this chapter,1 you should know the answers to these questions: ● What is patient monitoring, and why is it done? ● What are the primary applications of computerized patient-monitoring systems in the intensive-care unit? ● How do computer-based patient monitors aid health professionals in collecting, analyzing, and displaying data? ● What are the advantages of using microprocessors in bedside monitors? ● What are the important issues for collecting high-quality data either automatically or manually in the intensive-care unit? ● Why is integration of data from many sources in the hospital necessary if a computer is to assist in critical-care-management decisions? 17.1 What Is Patient Monitoring? Continuous measurement of patient parameters such as heart rate and rhythm, respira- tory rate, blood pressure, blood-oxygen saturation, and many other parameters have become a common feature of the care of critically ill patients. When accurate and imme- diate decision-making is crucial for effective patient care, electronic monitors frequently are used to collect and display physiological data. Increasingly, such data are collected using non-invasive sensors from less seriously ill patients in a hospital’s medical-surgical units, labor and delivery suites, nursing homes, or patients’ own homes to detect unex- pected life-threatening conditions or to record routine but required data efficiently. We usually think of a patient monitor as something that watches for—and warns against—serious or life-threatening events in patients, critically ill or otherwise. Patient monitoring can be rigorously defined as “repeated or continuous observations or meas- urements of the patient, his or her physiological function, and the function of life sup- port equipment, for the purpose of guiding management decisions, including when to make therapeutic interventions, and assessment of those interventions” (Hudson, 1985, p.

It’s Time to Start Using it! Capnography 101 Oxygenation and Ventilation What is the difference? Oxygenation and Ventilation Ventilation O Oxygenation (capnography) 2 (oximetry) CO Cellular 2 Metabolism Capnographic Waveform • Capnograph detects only CO2 from ventilation • No CO2 present during inspiration – Baseline is normally zero CD AB E Baseline Capnogram Phase I Dead Space Ventilation • Beginning of exhalation • No CO2 present • Air from trachea, posterior pharynx, mouth and nose – No gas exchange occurs there – Called “dead space” Capnogram Phase I Baseline A B I Baseline Beginning of exhalation Capnogram Phase II Ascending Phase • CO2 from the alveoli begins to reach the upper airway and mix with the dead space air – Causes a rapid rise in the amount of CO2 • CO2 now present and detected in exhaled air Alveoli Capnogram Phase II Ascending Phase C Ascending II Phase Early A B Exhalation CO2 present and increasing in exhaled air Capnogram Phase III Alveolar Plateau • CO2 rich alveolar gas now constitutes the majority of the exhaled air • Uniform concentration of CO2 from alveoli to nose/mouth Capnogram Phase III Alveolar Plateau Alveolar Plateau CD III AB CO2 exhalation wave plateaus Capnogram Phase III End-Tidal • End of exhalation contains the highest concentration of CO2 – The “end-tidal CO2” – The number seen on your monitor • Normal EtCO2 is 35-45mmHg Capnogram Phase III End-Tidal End-tidal C D AB End of the the wave of exhalation Capnogram Phase IV Descending Phase • Inhalation begins • Oxygen fills airway • CO2 level quickly

Analgesia and Sedation in Hospitalized Children By Elizabeth J. Beckman, Pharm.D., BCPS, BCCCP, BCPPS Reviewed by Julie Pingel, Pharm.D., BCPPS; and Brent A. Hall, Pharm.D., BCPPS LEARNING OBJECTIVES 1. Evaluate analgesics and sedative agents on the basis of drug mechanism of action, pharmacokinetic principles, adverse drug reactions, and administration considerations. 2. Design an evidence-based analgesic and/or sedative treatment and monitoring plan for the hospitalized child who is postoperative, acutely ill, or in need of prolonged sedation. 3. Design an analgesic and sedation treatment and monitoring plan to minimize hyperalgesia and delirium and optimize neurodevelopmental outcomes in children. INTRODUCTION ABBREVIATIONS IN THIS CHAPTER Pain, anxiety, fear, distress, and agitation are often experienced by GABA γ-Aminobutyric acid children undergoing medical treatment. Contributory factors may ICP Intracranial pressure include separation from parents, unfamiliar surroundings, sleep dis- PAD Pain, agitation, and delirium turbance, and invasive procedures. Children receive analgesia and PCA Patient-controlled analgesia sedatives to promote comfort, create a safe environment for patient PICU Pediatric ICU and caregiver, and increase patient tolerance to medical interven- PRIS Propofol-related infusion tions such as intravenous access placement or synchrony with syndrome mechanical ventilation. However, using these agents is not without Table of other common abbreviations. risk. Many of the agents used for analgesia and sedation are con- sidered high alert by the Institute for Safe Medication Practices because of their potential to cause significant patient harm, given their adverse effects and the development of tolerance, dependence, and withdrawal symptoms. Added layers of complexity include the ontogeny of the pediatric patient, ongoing disease processes, and presence of organ failure, which may alter the pharmacokinetics and pharmacodynamics of these medications.

COMMENTRY Handheld devices and informatics in anesthesia Prasanna Vadhanan,MD1, Adinarayanan S., DNB2 1Associate Professor, Department of Anaesthesiology, Vinayaka Missions Medical College & Hospital, Keezhakasakudimedu, Kottucherry Post, Karaikal, Puducherry 609609, (India) 2Associate Professor, Department of Anaesthesiology & Critical Care. The Jawaharlal Institute of Postgraduate Medical Education & Research, Dhanvantri Nagar, Gorimedu, Puducherry, 605006, (India) Correspondence: Dr. Prasanna Vadhanan, MD, No. 6, P&T Nagar, Mayiladuthurai 609001 (India); Phone: +919486489690; E-mail: [email protected] Received: 02 April 2016; Reviewed: 2 May 2016; Corrected: 02 June 2016; Accepted: 10 June 2016 ABSTRACT Handheld devices like smartphones, once viewed as a diversion and interference in the operating room have become an integral part of healthcare. In the era of evidence based medicine, the need to remain up to date with current practices is felt more than ever before. Medical informatics helps us by analysing complex data in making clinical decisions and knowing recent advances at the point of patient care. Handheld devices help in delivering such information at the point of care; however, too much reliance upon technology might be hazardous especially in an emergency situation. With the recent approval of robots to administer anesthesia, the question of whether technology can replace anesthesiologists from the operating room looms ahead. The anesthesia and critical care related applications of handheld devices and informatics

Sports Medicine Examination Content I. ROLE OF THE TEAM PHYSICIAN 1% A. Ethics B. Medical-Legal 1. Physician responsibility 2. Physician liability 3. Preparticipation clearance 4. Return to play 5. Waiver of liability C. Administrative Responsibilities II. BASIC SCIENCE OF SPORTS 16% A. Exercise Physiology 1. Training Response/Physical Conditioning a.Aerobic b. Anaerobic c. Resistance d. Flexibility 2. Environmental a. Heat b.Cold c. Altitude d.Recreational diving (scuba) 3. Muscle a. Contraction b. Lactate kinetics c. Delayed onset muscle soreness d. Fiber types 4. Neuroendocrine 5. Respiratory 6. Circulatory 7. Special populations a. Children b. Elderly c. Athletes with chronic disease d. Disabled athletes B. Anatomy 1. Head/Neck a.Bone b. Soft tissue c. Innervation d. Vascular 2. Chest/Abdomen a.Bone b. Soft tissue c. Innervation d. Vascular 3. Back a.Bone b. Soft tissue c. Innervation 1 d. Vascular 4. Shoulder/Upper arm a. Bone b. Soft tissue c. Innervation d. Vascular 5. Elbow/Forearm a. Bone b. Soft tissue c. Innervation d. Vascular 6. Hand/Wrist a. Bone b. Soft tissue c. Innervation d. Vascular 7. Hip/Pelvis/Thigh a. Bone b. Soft tissue c. Innervation d. Vascular 8. Knee a. Bone b. Soft tissue c. Innervation d. Vascular 9. Lower Leg/Foot/Ankle a. Bone b. Soft tissue c. Innervation d. Vascular 10. Immature Skeleton a. Physes b. Apophyses C. Biomechanics 1. Throwing/Overhead activities 2. Swimming 3. Gait/Running 4. Cycling 5. Jumping activities 6. Joint kinematics D. Pharmacology 1. Therapeutic Drugs a. Analgesics b. Antibiotics c. Antidiabetic agents d. Antihypertensives e.

Pathology and Laboratory Medicine 1 and hepatic pathology. The rotation consists of daily interpretation of Pathology and subspecialty biopsies, participation in subspecialty conferences, slide set study, and assigned readings. Students participate in their own Laboratory Medicine learning by setting their rotation objectives with faculty at the start of their elective and following through with a schedule of clinical, laboratory and core lecture conferences. Students will need to obtain the appropriate Pathologists play many roles in medicine, from interpreting surgical staff members' permission for the rotation as follows: dermatopathology biopsies to supervising clinical laboratory testing. It has been estimated (Garth Fraga); neuropathology (Kathy Newell); renal pathology (Timothy that 70% of all medical decisions are based on data generated by Fields); breast pathology (Fang Fan); hepatic pathology (Maura O'Neil). pathology departments. The department of Pathology and Laboratory Prerequisite: Completion of the core clinical clerkships and permission of Medicine at KUMC plays an integral role in the core curriculum and also the faculty. LEC. offers elective courses to medical students interested in learning more about laboratory practice. Students in elective rotations participate in daily teaching conferences and specimen “sign-out” at the University of Kansas Hospital. They receive hands-on exposure to pathology technical methodology in the surgical pathology suite, cytopathology and hematopathology. PAON 920. Molecular Medicine: Approaches & Ethics. 2 Hours. Molecular Medicine: Approaches Ethics is a two semester course for first year MD-PhD students taught by the Director of the MD- PhD Program, with other faculty from the basic science and clinical departments. Through lectures, small group discussion, online modules, evaluation of primary literature, and presentations/discussions with current KUMC faculty, students will be introduced to the process of scientific investigation.

Department of Oral- and Maxillofacial Surgery, Semmelweis University Budapest Head of Department: Dr. Németh Zsolt General anaesthesia in oral surgery and outpatient surgery History 1844 Horace Wells nitrous oxide extraction of one of his own wisdom teeth by a colleague 1846 William Morton (pupil of Wells) ether extraction 1946 introduction of lidocaine General anaesthesia should be strictly limited to those patients and clinical situations in which local anaesthesia (with or without sedation) is not an option. Bourne JG. General anaesthesia in the dental surgery. B Dental J 1962; 113: 54-7. Coleman F. The history of nitrous oxide anaesthesia. Dental Record 1942; 62: 143-9 Naveen Malhotra General Anaesthesia for Dentistry ndian Journal of Anaesthesia 2008;52:Suppl (5):725-737 Types of general anaesthesia Outpatient anaesthesia • Dental chair anaesthesia Relative analgesia for simple extraction • Day care anaesthesia Conscious sedation (Sedoanalgesia) for minor oral surgery In patient anaesthesia Intubation with or without neuromuscular blocking for complicated extractions, oral- and maxillofacial surgical procedures Indications of general anaesthesia • Acute infection (pain) • Children • Mentally challenged patients • Dental phobia • Allergy to local anaesthetics • Extensive dentistry & facio-maxillary surgery Equipments • anaesthesia machine, vaporizers • oxygen, nitrous oxide • breathing circuits (adult and pediatric) • nasal and facial masks • oral and nasal air-ways • different laryngoscopes with all sizes of blades • nasal and

1788 General Anaesthetics metabolic pathways include hydroxylation of the 3. Lökken P, et al. Conscious sedation by rectal administration of Methohexital Sodium (BANM, rINNM) midazolam or midazolam plus ketamine as alternatives to gener- cyclohexone ring and conjugation with glucuronic ac- al anesthesia for dental treatment of uncooperative children. Compound 25398; Enallynymalnatrium; Méthohexital Sodique; id. The beta phase half-life is about 2.5 hours. Keta- Scand J Dent Res 1994; 102: 274–80. Methohexitone Sodium; Metohexital sódico; Natrii Methohexi- 4. Louon A, et al. Sedation with nasal ketamine and midazolam for talum. mine is excreted mainly in the urine as metabolites. It cryotherapy in retinopathy of prematurity. Br J Ophthalmol crosses the placenta. 1993; 77: 529–30. Натрий Метогекситал 5. Zsigmond EK, et al. A new route, jet-injection for anesthetic in- C14H17N2NaO3 = 284.3. ◊ References. duction in children–ketamine dose-range finding studies. Int J CAS — 309-36-4; 22151-68-4; 60634-69-7. 1. Clements JA, Nimmo WS. Pharmacokinetics and analgesic ef- Clin Pharmacol Ther 1996; 34: 84–8. ATC — N01AF01; N05CA15. fect of ketamine in man. Br J Anaesth 1981; 53: 27–30. 6. Kronenberg RH. Ketamine as an analgesic: parenteral, oral, rec- tal, subcutaneous, transdermal and intranasal administration. J ATC Vet — QN01AF01; QN05CA15. 2. Grant IS, et al. Pharmacokinetics and analgesic effects of IM and Pain Palliat Care Pharmacother 2002; 16: 27–35. oral ketamine. Br J Anaesth 1981; 53: 805–9. Pharmacopoeias. US includes Methohexital Sodium for In- jection. 3. Grant IS, et al. Ketamine disposition in children and adults. Br J Nonketotic hyperglycinaemia.

Local Anaesthesia for Major General Surgical Postgrad Med J: First Published As 10.1136/Pgmj.72.844.105 on 1 February 1996

Postgrad Med J' 1996; 72: 105-108 C) The Fellowship of Postgraduate Medicine, 1996 Local anaesthesia for major general surgical Postgrad Med J: first published as 10.1136/pgmj.72.844.105 on 1 February 1996. Downloaded from procedures A review of 1 16 cases over 12 years A Dennison, N Oakley, D Appleton, J Paraskevopoulos, D Kerrigan, J Cole, WEG Thomas Summary ation was collated from medical notes, anaes- Between 1980 and 1992, 116 patients had thetic records and operation notes. Cases in either a simple mastectomy (32) or intra- which local anaesthesia was augmented by abdominal procedures (84) under local regional or intravenous techniques were exc- anaesthesia (0.5-1% lignocaine with luded from the study. Patients were not 1:200 000 adrenaline). A wide variety of included ifthey had neck/head or limb surgery, general surgical procedures were feasible abdominal hernia repair, simple drainage of using only supplementary intravenous intra-abdominal abscess or any minor proce- sedation (54%). Complications were un- dures including peritoneo-venous shunts, common and related to surgical proce- laparoscopic or endoscopic procedures. dure (three incorrect diagnoses, three The 116 patients presented in the study are procedures impossible) rather than the those who had intra-abdominal surgery (84; 53 anaesthetic technique. There were no women, 31 men) or simple mastectomy (32). anaesthetic toxicity or postoperative pro- The median age was 74 years (range 27-92) blems. Local anaesthesia is extremely and all the patients were grade III or worse on safe and facilitates larger surgical proce- the American Society of Anaesthesiologists dures than is generally appreciated.

ANESTHETIC MONITORING Lyon Lee DVM PhD DACVA MONITORING ANESTHETIC DEPTH • The central nervous system is progressively depressed under general anesthesia. • Different stages of anesthesia will accompany different physiological reflexes and responses (see table below, Guedel’s signs and stages). Table 1. Guedel’s (1937) Signs and Stages of Anesthesia based on ‘Ether’ anesthesia in cats. Stages Description 1 Inducement, excitement, pupils constricted, voluntary struggling Obtunded reflexes, pupil diameters start to dilate, still excited, 2 involuntary struggling 3 Planes There are three planes- light, medium, and deep More decreased reflexes, pupils constricted, brisk palpebral reflex, Light corneal reflex, absence of swallowing reflex, lacrimation still present, no involuntary muscle movement. Ideal plane for most invasive procedures, pupils dilated, loss of pain, Medium loss of palpebral reflex, corneal reflexes present. Respiratory depression, severe muscle relaxation, bradycardia, no Deep (early overdose) reflexes (palpebral, corneal), pupils dilated Very deep anesthesia. Respiration ceases, cardiovascular function 4 depresses and death ensues immediately. • Due to arrival of newer inhalation anesthetics and concurrent use of injectable anesthetics and neuromuscular blockers the above classic signs do not fit well in most circumstances. • Modern concept has two stages simply dividing it into ‘awake’ and ‘unconscious’. • One should recognize and familiarize the reflexes with different physiologic signs to avoid any untoward side effects and complications • The system must be continuously monitored, and not neglected in favor of other signs of anesthesia. • Take all the information into account, not just one sign of anesthetic depth. • A major problem faced by all anesthetists is to avoid both ‘too light’ anesthesia with the risk of sudden violent movement and the dangerous ‘too deep’ anesthesia stage.

Current Fluid Therapy Topics and Recommendations During Anesthetic Procedures Andrew Claude, DVM, DACVAA Mississippi State University Mississippi State, MS • Intravenous fluid administration is recommended during general anesthesia, even during short procedures. • The traditional IV fluid rate of 10 mls/kg/hr during general anesthesia is under review. • Knowledge of a variety of IV fluids, and their applications, is essential when choosing anesthetic protocols for different medical procedures. Anesthetic drug effects on the cardiovascular system • Almost all anesthetic drugs have the potential to adversely affect the cardiovascular system. • General anesthetic vapors (isoflurane, sevoflurane) cause a dose-dependent, peripheral vasodilation. • Alpha-2 agonists initially cause peripheral hypertension with reflex bradycardia leading to a dose-dependent decreased patient cardiac index. As the drug effects wane, centrally mediated bradycardia and hypotension are common side effects. • Phenothiazine (acepromazine) tranquilizers are central dopamine and peripheral alpha receptor antagonists. This family of drugs produces dose-dependent sedation and peripheral vasodilation (hypotension). • Dissociative NMDA antagonists (ketamine, tiletamine) increase sympathetic tone soon after administration. When dissociative NMDA antagonists are used as induction agents in patients with sympathetic exhaustion or decreased cardiac reserve (morbidly ill patients), these drugs could further depress myocardial contractility. • Propofol can depress both myocardial contractility and vascular tone resulting in marked hypotension. Propofol’s negative effects on the cardiovascular system can be especially problematic in ill patients. • Potent mu agonist opioids can enhance vagally induced bradycardia. Why is IV fluid therapy important during general anesthesia? • Cardiac output (CO) equals heart rate (HR) X stroke volume (SV); IV fluids help maintain adequate fluid volume, preload, and sufficient cardiac output.