NEURAXIAL ANESTHESIA Basic Overview
By: Ismail A. Mehr, M.D. December 29th, 2014
Disclosure
Ismail Mehr MD I have NO actual or potential conflict of interest in relation to this activity. I do not have any relevant financial relationships with any commercial interests.
Neuraxial Anesthesia
Epidural Intrathecal – “Spinal”
Neuraxial Anesthesia ď Ž
ď Ž
Neuraxial anesthesia had its greatest impact in obstetrics It was first used for surgical procedures at the turn of the last century
Neuraxial Anesthesia AKA
Spinal/Epidural Anesthesia
Blunts stress response Decreases intra-operative blood loss Decreases thromboembolic events Decreases morbidity and mortality
ANATOMY
The Spine
33 Vertebrae 7 CERVICAL 12 THORACIC 5 LUMBAR 5 SACRAL 4 COCCYGEAL
ANATOMY
ANATOMY
NEURAXIAL ANESTHESIA PHYSIOLOGY
Autonomic Nervous System
Parasympathetic Nervous System
Craniosacral outflow
Sympathetic Nervous System
Thoracolumbar outflow
T1 – L2
Site of Sympathetic Blockade
NEURAXIAL ANESTHESIA PHYSIOLOGY
Cardiovascular System:
Decreased PVR Decreased venous return Decreased HR
Profound hypotension in the setting of lost compensatory mechanisms with unopposed vagal tone can lead to cardiac arrest.
NEURAXIAL ANESTHESIA PHYSIOLOGY
Pulmonary System:
GI System
Increased peristalsis
Urinary System
Decreased vital capacity Decreased accessory muscle tone
Urinary retention
Neuroendocrine System
Stress response inhibition
NEURAXIAL ANESTHESIA PHARAMACOLOGY
Neuraxial opioids and local anesthetic synergy
Opioids:
Local anesthetics (epidural)
Fentanyl Morphine Sufentanil Bupivicaine Ropivicaine
Local anesthetics (spinal)
Lidocaine Tetracaine Bupivicaine
NEURAXIAL ANESTHESIA SPINAL ANESTHESIA-INTRATHECAL
In use since early 1900’s Reserved for surgeries below umbilicus
Hernia repairs Gynecological procedures Urological procedures Lower extremity procedures (vascular/ortho) Obstetrics
NEURAXIAL ANESTHESIA PROCEDURE
SPINAL
Positioning: lat decub, sitting Monitoring: BP & HR Approach: midline or paramedian Sterile technique Local skin infilteration Passage of spinal needle
+ CSF flow, no heme, no parasthesias
Injection of local/opioid mixture Supine positioning w/ left uterine tilt VS/block assessment
NEURAXIAL ANESTHESIA EPIDURAL ANESTHESIA
1921 – First epidural May be utilized as a primary anesthetic Adjuvant to general anesthesia Post-op pain management Best reserved for surgeries below the umbilicus
NEURAXIAL ANESTHESIA EPIDURAL ANESTHESIA
Post-op pain
Intra-abdominal procedures Thoracic surgery/trauma Vascular procedures Orthopedics – joint replacement
NEURAXIAL ANESTHESIA PROCEDURE
EPIDURAL
Positioning: lat decub, sitting Monitoring: BP & HR Approach: midline Sterile technique Local skin infilteration
NEURAXIAL ANESTHESIA PROCEDURE
EPIDURAL
Passage of epidural needle
Passage of epidural catheter ~ 4–5cm Test dose : local/epi
+ve LOR to saline/air without CSF/heme/parathesias
R/O intrathecal and intravascular placement
Bolus/continuous infusion
NEURAXIAL ANESTHESIA
SPINAL ANESTHESIA
Less time to perform Rapid onset Denser quality of block
EPIDURAL ANESTHESIA Continuous anesthetic Less sympathetic block Post-op analgesia
NEURAXIAL ANESTHESIA CONTRAINDICATIONS
RELATIVE
Sepsis Uncooperative patient Preexiting neurologic deficits Stenotic valvular heart lesions Severe spinal deformity
CONTROVERSIAL
Prior back surgery at the site of injection Inability to communicate with patient Complicated surgery
Prolonged operation Major blood loss Maneuvers that compromise respiration
NEURAXIAL ANESTHESIA CONTRAINDICATIONS
ABSOLUTE
Infection at site Patient refusal Coagulopathy or bleeding diathesis Severe hypovolemia Increased ICP Severe Aortic stenosis Severe Mitral Stenosis
NEURAXIAL ANESTHESIA COMPLICATIONS
Backache Post-Dural Puncture Headache Total spinal Neurological injury Infections Spinal/Epidural hematoma
Disclosure
Ismail Mehr MD I have NO actual or potential conflict of interest in relation to this activity. I do not have any relevant financial relationships with any commercial interests.