Epidural Technique In Obstetric Anesthesia

176 Pages·2020·11.931 MB·English

by  Giorgio Capogna

Epidural Technique In
Obstetric Anesthesia
Giorgio Capogna
123
Epidural Technique In Obstetric
Anesthesia
Giorgio Capogna
Epidural Technique
In Obstetric Anesthesia
Giorgio Capogna
European School of Obstetric Anesthesia
Rome
Italy
ISBN 978-3-030-45331-2 ISBN 978-3-030-45332-9 (eBook)
https://doi.org/10.1007/978-3-030-45332-9
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To Rita and Emanuele
Preface
èpi- [from the Greek. ἐπί “above, in, more”]
pèri- [from the Greek. περί, περι- “around”]
èxtra- [from the Latin. extra “outside”]
The terms “epidural,” “peridural,” and “extradural” are basically
synonyms.
To be anatomically precise, peridural should be the most correct term,
because it implies that the space is around the dura and therefore it envelops
the entire dural sac, while epidural refers to a space that is upon or on the
dural sac.
Peridural is most used in countries whose language comes from Latin,
extradural is the term currently used in British English-speaking countries,
and epidural is currently used in Standard English-speaking countries.
The term “space” is used to indicate the region lying between the dura and
the bony walls of the spinal canal. However, the term space is not completely
exact, because it is not an empty space, but a place that is filled mainly with
fat and with other anatomical structures, and therefore should be called
“region” rather than “space.” As we will discuss in the chapter devoted to the
anatomy, the most recent anatomical findings support the idea that the epi-
dural region is in part real and in part virtual.
In this text, I will use the most commonly used term: epidural space.
Epidural block is a form of peripheral nerve block accomplished by intro-
ducing local anesthetic agents into the epidural space. In this way, the local
anesthetic affects the nerve fibers beyond their arachnoid-dural coverings as
they lie in the intervertebral foramen, paravertebral space, or sacral canal.
Our masters J. J. Bonica and P. Bromage wrote everything that could be
said on the subject, for which I will necessarily refer to their teachings; how-
ever, more or less 70 years have passed from their cornerstone publications,
and some new things have been discovered, some others have been confirmed
with modern methods, and new techniques face the horizon. Clinical practice
has also slightly changed. For this reason, I wanted to write this book, to
transmit their knowledge and experience to the new generations, adding a
little of my updated practical experience.
This book is intended for all colleague anesthetists, but in particular those
who want to practice or who already practice analgesia in obstetrics, and
therefore it will exclusively describe the lumbar approach to the epidural
space which is the one used in obstetrics.
vii
viii Preface
The epidural block has been known universally for a long time; however,
its specific teaching is beginning to be lost, as this practice is mainly confined
within the scope of obstetric analgesia. For this reason, I hope this book will
help my young colleagues to learn and appreciate a fundamental technique
for the anesthesiologist and my older colleagues to review their technique to
better teach it to future generations.
Rome, Italy Giorgio Capogna
Contents
1 History of Lumbar Epidural Block . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Was the Very First a Spinal or an Epidural Anesthesia? . . . . . 1
1.2 The First Epidural Approach: The Caudal . . . . . . . . . . . . . . . . 4
1.3 Lumbar Epidural . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.4 Continuous Lumbar Epidural . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.5 Modern Epidural Analgesia . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2 Anatomy of the Lumbar Epidural Region . . . . . . . . . . . . . . . . . . 19
2.1 Vertebral Column . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.2 Lumbar Vertebra. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.3 Ligamentum Flavum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.4 Interspinous and Supraspinous Ligaments . . . . . . . . . . . . . . . . 23
2.5 Muscles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.6 Intervertebral Foramen and Its Ligaments . . . . . . . . . . . . . . . . 27
2.7 Epidural Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
2.7.1 Epidural Fat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
2.7.2 Nerve Roots and Nerve Root Cuff . . . . . . . . . . . . . . . . 31
2.7.3 Internal Vertebral Venous Plexus, Epidural
Arteries, and Lymphatics . . . . . . . . . . . . . . . . . . . . . . . 32
2.8 Dural Sac . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
2.8.1 Dura Mater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
2.8.2 Arachnoid Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
2.8.3 Subdural and Intradural Space . . . . . . . . . . . . . . . . . . . 35
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
3 Distribution of a Solution in the Epidural Space . . . . . . . . . . . . . 39
3.1 Sites of Action, Dynamics of Nerve Block,
and Physicochemical Properties of Local Anesthetics . . . . . . . 39
3.2 Local Tissue Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
3.3 Absorption and Elimination . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
3.4 Spread of a Solution in the Epidural Space . . . . . . . . . . . . . . . 42
3.4.1 Patient Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 42
3.4.2 Technical Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
3.4.3 Epidural Pressure and Adjacent Pressures . . . . . . . . . . 49
3.4.4 Composition of the Solution Injected: Dose,
Volume, and Concentration—Adjuvant Drugs . . . . . . 49
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
ix
x Contents
4 Fundamentals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
4.1 Epidural Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
4.1.1 Epidural Needles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
4.1.2 Epidural Syringes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
4.1.3 Epidural Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
4.1.4 Epidural Catheters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
4.1.5 Epidural Filters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
4.1.6 Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
4.2 Patient Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
4.2.1 Positioning the Patient . . . . . . . . . . . . . . . . . . . . . . . . . 67
4.3 Landmarks Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.3.1 Manual Palpation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.3.2 Ultrasound Identification . . . . . . . . . . . . . . . . . . . . . . . 69
4.4 Skin Disinfection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
4.5 Superficial Tissues’ Local Anesthesia . . . . . . . . . . . . . . . . . . . 72
4.5.1 Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
5 Epidural Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
5.1 Loss-of-Resistance-to-Saline Technique . . . . . . . . . . . . . . . . . 77
5.2 False or Pseudo-Loss of Resistance . . . . . . . . . . . . . . . . . . . . . 81
5.3 Bone Contact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
5.4 Observation and Aspiration of the Needle . . . . . . . . . . . . . . . . 84
5.5 Rebound Test and Partially Inserted Bevel
of the Needle in the Epidural Space . . . . . . . . . . . . . . . . . . . . . 85
5.6 Loss of Resistance to Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
5.7 Techniques Based on Epidural Negative Pressure . . . . . . . . . . 87
5.8 Paramedian Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
5.9 Forces Involved During Needle Insertion . . . . . . . . . . . . . . . . 88
5.10 Catheter Insertion, Needle Removal,
and Catheter Fixation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
5.11 Catheter Aspiration and Test Dose . . . . . . . . . . . . . . . . . . . . . . 92
5.12 Confirmation of Catheter Location in the Epidural Space . . . . 94
5.12.1 Epidural Stimulation Test. . . . . . . . . . . . . . . . . . . . . . . 94
5.12.2 Epidural Pressure Waveform Analysis . . . . . . . . . . . . . 94
Appendix 1: Epidural Technique in Five Steps . . . . . . . . . . . . . . . . 95
Appendix 2: Epidural Technique—The Three Immediate
Safety Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Appendix 3: Epidural Technique—Problem-Solving . . . . . . . . . . . 96
Doubtful Increase in Resistance/False Loss of Resistance . . . . . 96
Bone Contact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
6 New Techniques and Emerging Technologies to Identify
the Epidural Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
6.1 Guiding the Needle in the Epidural Space . . . . . . . . . . . . . . . . 99
6.1.1 Ultrasound-Guided Techniques . . . . . . . . . . . . . . . . . . 99
6.1.2 Augmented Reality System for Epidural Anesthesia . . 102
6.1.3 Acoustic Radiation Force Impulse Imaging . . . . . . . . 102
Contents xi
6.2 Identifying the Entry into the Epidural Space . . . . . . . . . . . . . 102
6.2.1 Epidural Pressure Checker . . . . . . . . . . . . . . . . . . . . . . 103
6.2.2 Continuous Real-Time Pressure-Sensing
Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
6.2.3 Bioimpedance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
6.2.4 Optical Reflectance Spectroscopy . . . . . . . . . . . . . . . . 106
6.2.5 Optical Coherence Tomography . . . . . . . . . . . . . . . . . 107
6.3 Confirming the Catheter Location in Epidural Space . . . . . . . 107
6.3.1 Near-Infrared Tracking System . . . . . . . . . . . . . . . . . . 108
6.3.2 Ultrasound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
6.3.3 Optical Fiber Technology for Epidural
Needle (OFTEN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
6.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
7 Combined Spinal-Epidural Technique . . . . . . . . . . . . . . . . . . . . . 111
7.1 History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
7.2 Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
7.3 Single-Interspace Technique . . . . . . . . . . . . . . . . . . . . . . . . . . 113
7.3.1 Two Needles in the Same Interspace . . . . . . . . . . . . . . 113
7.3.2 Needle-Through-Needle (Single Channel) . . . . . . . . . 113
7.3.3 Needle-Beside-Needle (Double Channel) . . . . . . . . . . 114
7.4 Double-Interspace Technique . . . . . . . . . . . . . . . . . . . . . . . . . 116
7.5 Optimal Length of the Spinal Needle Beyond
the Epidural Needle Tip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
7.6 Risk of Epidural Catheter Subarachnoid Migration . . . . . . . . . 116
7.7 Subarachnoid Spread of Epidurally Administered
Drugs and the Dural Puncture Technique (DPE) . . . . . . . . . . . 117
7.8 Failure/Problems with the Spinal Component . . . . . . . . . . . . . 117
7.9 Epidural Volume Extension Technique . . . . . . . . . . . . . . . . . . 119
7.10 Test Dose After CSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
8 Contraindications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
8.1 Skin and Soft-Tissue Alterations at the Site
of the Puncture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
8.1.1 Bacterial Infection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
8.1.2 Fungal Infection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
8.1.3 Viral Infections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
8.1.4 Tattoos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
8.2 Systemic Infection: Febrile Patient . . . . . . . . . . . . . . . . . . . . . 123
8.2.1 Systemic Viral Infections: HIV,
Herpes Simplex, Herpes Zoster
(Alpha Herpesvirus, HHV1, -2, and -3) . . . . . . . . . . . . 123
8.3 Patients Receiving Anticoagulants . . . . . . . . . . . . . . . . . . . . . . 124
8.4 Disorders of Coagulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
8.4.1 Inherited Coagulation Disorders . . . . . . . . . . . . . . . . . 124
8.4.2 Platelet Disorders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
8.5 Intracranial Lesions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126