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    Sevoflurane Anaesthesia in Dogs :

    Clinical Implications and Applications

    Ingeborgh Polis

    Proefschrift ter verkrijging van de graad van Doctor in de Diergeneeskundige

    Wetenschappen (PhD) aan de Faculteit Diergeneeskunde, Universiteit Gent

    Promotor: Prof. Dr. F. Gasthuys

    Co-promotors: Prof. Dr. L. Van Ham Prof. Dr. Y. Moens

    Department of Small Animal Medicine and Clinical Biology

    Faculty of Veterinary Medicine

    Ghent University

    ISBN 90-5864-019-1

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    DEDICATION

    To my parents, for their lifelong love and encouragement.

    To Geert, my support in bad days.

    To Bram, the twinkle in my eyes.

    Ingeborgh

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    CONTENTS

    List of abbreviations

    GENERAL INTRODUCTION 1

    SCIENTIFIC AIMS 5

    CHAPTER 1 SEVOFLURANE: PHYSICO-CHEMICAL PROPERTIES 9

    AND MAC

    Introduction 11 History of inhalant anaesthetic agents 11 Molecular structure and physical properties of sevoflurane 15 Anaesthetic properties of sevoflurane 18 Minimum alveolar concentration (MAC) 24 References 27

    CHAPTER 2 SEVOFLURANE: INFLUENCES ON BODY 35

    SYSTEMS AND ECONOMIC CONSIDERATIONS

    Summary 37 Introduction 37 Effects on central nervous system 38 Effects on cardiovascular system 42 Effects on respiratory system 45 Hepatic effects 47 Renal effects 50 Economic considerations 55 Conclusion 58 References 59

    INTRODUCTION TO CHAPTERS 3 AND 4 75

    CHAPTER 3 RECOVERY TIMES AND EVALUATION OF CLINICAL 79

    HEMODYNAMIC PARAMETERS OF SEVOFLURANE, ISOFLURANE AND HALOTHANE ANAESTHESIA IN

    MONGREL DOGS.

    Summary 81 Introduction 82 Materials and Methods 83

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    Results 86 Discussion 91 References 99

    CHAPTER 4 THE INFLUENCE OF VENTILATION MODE 103

    (SPONTANEOUS VENTILATION, IPPV AND PEEP) ON CARDIOPULMONARY PARAMETERS

    IN SEVOFLURANE ANAESTHETIZED DOGS.

    Summary 105 Introduction 106 Materials and Methods 107 Results 113 Discussion 119 References 126

    INTRODUCTION TO CHAPTER 5 131

    CHAPTER 5 THE EFFECTS OF INTRATHORACIC PRESSURE DURING 135

    CONTINUOUS TWO-LUNG VENTILATION FOR THORACOSCOPY ON THE CARDIORESPIRATORY

    PARAMETERS IN SEVOFLURANE ANAESTHETIZED DOGS.

    Summary 137 Introduction 138 Materials and Methods 140 Results 146 Discussion 154 References 161

    INTRODUCTION TO CHAPTERS 6, 7 AND 8 165

    CHAPTER 6 ARTERIAL CATHETERISATION AND VASCULAR 169

    ACCESS PORT IMPLANTATION FOR BLOOD SAMPLING AND CONTINUOUS BLOOD PRESSURE

    MEASUREMENT IN DOGS.

    Summary 171 Introduction 171 Materials and Methods 173 Results 180 Discussion 181 References 185

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    CHAPTER 7 PERIANAESTHETIC CARDIOPULMONARY, SEDATIVE 187

    AND ANTINOCICEPTIVE EFFECTS OF A LONG ACTING FORMULATION OF SUFENTANIL ADMINISTERED

    BEFORE SEVOFLURANE ANAESTHESIA IN DOGS.

    PART I. CARDIOPULMONARY EFFECTS 187

    Summary 189 Introduction 190 Materials and Methods 193 Results 199 Discussion 210 References 215

    CHAPTER 8 PERIANAESTHETIC CARDIOPULMONARY, SEDATIVE 221

    AND ANTINOCICEPTIVE EFFECTS OF A LONG ACTING FORMULATION OF SUFENTANIL ADMINISTERED

    BEFORE SEVOFLURANE ANAESTHESIA IN DOGS.

    PART II. SEDATIVE AND ANTINOCICEPTIVE EFFECTS 221

    Summary 223 Introduction 224 Materials and Methods 225 Results 231 Discussion 237 References 242

    GENERAL DISCUSSION 247

    References 260

    SUMMARY 265

    SAMENVATTING 271

    DANKWOORD 277

    CURRICULUM VITAE 281

    PUBLICATIONS 283

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    LIST OF ABBREVIATIONS AA % end tidal anaesthetic agent percentage AR artificial respiration ASA american society of anaesthesiologists BSA body surface area BWT body weight CBF cerebral blood flow CI cardiac index CO cardiac output CO2ET end tidal carbon dioxide percentage CPAP continuous positive airway pressure CV controlled ventilation DAP diastolic arterial blood pressure DPAP diastolic pulmonary artery pressure FA alveolar anaesthetic concentration Fi inspired concentration FiAA % inspiratory anaesthetic agent concentration FiO2 inspiratory oxygen fraction Halo halothane HCO3

    - plasma bicarbonate concentration HPV hypoxic pulmonary vasoconstriction HR heart rate ID internal diameter IM intramuscular IPPV intermittent positive pressure ventilation Iso isoflurane ITP intrathoracic pressure IV intravenous LA long acting LVSWI left ventricular stroke work index MAC minimum alveolar concentration MAP mean arterial blood pressure Min-max minimum and maximum MPAP mean pulmonary artery pressure MVV minute ventilation volume OLV one lung ventilation PA alveolar partial pressure PAP pulmonary artery pressure PaCO2 arterial carbon dioxide tension PCV packed cell volume PCWP pulmonary capillary wedge pressure

  • LIST OF ABBREVIATIONS

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    PEEP positive end expiratory pressure Pinsp inspiratory pressure PO per os PO2 arterial oxygen tension PVR pulmonary vascular resistance RAP right atrial pressure RR respiratory rate RVSWI right ventricular stroke work index SAP systolic arterial blood pressure SBC standard bicarbonate concentration SBE standard base excess SC subcutaneous Sevo sevoflurane SI stroke index SPAP systolic pulmonary artery pressure SpO2 % peripheral haemoglobin saturation SpV spontaneous ventilation SV stroke volume SVR systemic vascular resistance TLV two lung ventilation TV tidal volume VAP vascular access port

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    GENERAL INTRODUCTION

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  • GENERAL INTRODUCTION

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    The last decades a very impressive progress has been made

    in diagnostic as well as surgical techniques. As a consequence the

    need for a safe and stable long-standing anaesthesia during these

    procedures increases. Inhalation anaesthetics are very useful for this

    purpose. Halothane has being used for several decades in veterinary

    medicine and is still a valuable compound in many clinical settings.

    However, halothane is not an ideal anaesthetic drug. This is

    not surprising as an ideal volatile anaesthetic compound has to fulfil

    many criteria: minimal or no depressing effects on vital functions such

    as respiration and circulation, rapid onset of action, beneficial

    interaction with premedication and anaesthesia-inducing drugs, not to

    mention low health hazard for the anaesthetists, low flammability and

    the lack of need for expensive vaporizers.

    The last decades several new volatile anaesthetics have been

    developed such as isoflurane, desflurane and sevoflurane in order to

    obtain drugs with more beneficial and less side effects than the

    previous ones. Some of these drugs like isoflurane have been studied

    extensively in dogs, in experimental as well as clinical settings. The

    results of such studies indicate that new drugs may be superior for

    some but not all aspects leading to nuanced conclusions.

    Sevoflurane has been studied widely in humans. The findings

    are interesting in order to have an idea of the profile of this almost

    unknown drug in veterinary medicine. In humans its lack of airway

    pungency and mainly its low blood-gas solubility induce a fast

    induction and recovery from anaesthesia. Sevoflurane has little

    influence on cerebral perfusion and intracranial pressure. Depression

    of cardiac output is only reported at higher concentrations. Both

    characteristics make it the agent of choice in neurological and cardiac

  • GENERAL INTRODUCTION

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    patients. However one should be careful by extrapolating these

    results to canine medicine. Therefore several studies were undertaken

    in dogs in order to investigate some clinical implications and

    applications of sevoflurane.

    In the first part of this thesis (chapter 1 and 2)

    physicochemical and pharmacological properties of sevoflurane are

    extensively reviewed and compared with other inhalation

    anaesthetics.

    In the second part own studies on sevoflurane in dogs are

    described. These studies deal with several pharmacological and

    clinical aspects of sevoflurane anaesthesia: recovery times and

    haemodynamics in comparison to other anaesthetics (chapter 3);

    influence of ventilation mode (chapter 4) and thoracoscopy (chapter 5)

    on cardiopulmonary parameters; vascular access port implantation

    (chapter 6) in order to study the influence of sufentanil long-acting

    premedication on haemodynamics (chapter 7) and analgesic effects

    (chapter 8) of sevoflurane.

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    SCIENTIFIC AIMS

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  • SCIENTIFIC AIMS

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    1/ To compare the recovery times and clinical haemodynamic

    parameters of sevoflurane, isoflurane and halothane anaesthesia in

    mongrel dogs.

    2/ To investigate the influence of ventilation mode (spontaneous

    ventilation, IPPV and PEEP) on cardiopulmonary parameters in

    sevoflurane anaesthetized dogs.

    3/ To determine the effects of intrathoracic pressure elevation on

    cardio-respiratory parameters during sevoflurane anaesthesia with

    continuous two-lung ventilation for thoracoscopy in dogs.

    4/ To describe the vascular access port implantation for blood

    sampling and continuous blood pressure measurement in dogs.

    5/ To examine the haemodynamic influences of a long-acting

    formulation of sufentanil administered at different time