By Dr Sajida Pharm D 16 th May

 The first spinal analgesia was administered in 1885 by Leonard Corning (1855–1923), a neurologist in New York. [1] He was experimenting with cocaine on the spinal nerves of a dog when he accidentally pierced the dura mater.Leonard Corning [1]cocainespinal nervesdura mater  The first planned spinal anaesthesia for surgery in man was administered by August Bier (1861–1949) on 16 August 1898, in Kiel, when he injected 3 ml of 0.5% cocaine solution into a 34-year-old labourer. [2] After using it on 6 patients, he and his assistant each injected cocaine into the other's spine. They recommended it for surgeries of legs, but gave it up due to the toxicity of cocaine.August BierKiel [2] spine

Defination  local anesthetic injection into lumbar subarachnoid space. Site of action: ◦ Primary: preganglionic fibers leading the spinal cord in the anterior rami ◦ Secondary: superficial spinal cord layers  Mechanism  Regardless of the anaesthetic agent (drug) used, the desired effectanaesthetic agent  to block the transmission of afferent nerve signals from peripheral nociceptors.nociceptors  Sensory signals from the site are blocked, thereby eliminating pain.

Most commonly used agents: Tetracaine (pontocaine),  lidocaine (Xylocaine),  bupivacaine (Marcaine)  Characteristics of some drugs: Bupivacaine (Marcaine): More effective than tetracaine (pontocaine) in preventing lower-extremity tourniquet pain (orthopedic surgery cases) Chloroprocaine (Nesacaine)  Not placed in subarachnoid space due to neurotoxicity risk

 Specific gravity of the local anesthetic solution  Glucose addition: increased specific gravity above that of CSF (hyperbaric)  Distilled water addition: decreased specific gravity below that of CSF (hypobaric)

◦ Consequences of sympathetic blockade:  Arteriolar dilation  No significant effect on systemic BP due to compensatory upper extremity vasoconstriction.  No cerebrovascular vasoconstriction  Total sympathetic blockade due to spinal anesthesia: associated with a reduction in systemic vascular resistance of < 15%.  Rationale: arteriolar smooth muscle does not dilate maximally because of intrinsic tone  Many major cardiovascular response secondary to spinal anesthesia due to:  Effects on venous circulation  Venules: minimal intrinsic tone retention; maximal dilation during spinal anesthesia

  Reduced venous return to heart leads to decreased cardiac output and consequently decreased systemic blood- pressure  Severe systemic hypotension in hypovolemic patients  Treatment:  Alpha-adrenergic receptor agonist administration  Slightly-head down patient repositioning

 Cardiac slowing (bradycardia) secondary to blockade of preganglionic cardiac accelerator nerves (T1 to T4)  This bradycardia response may be worsened in the presence of reduced preload and as a result, reduce stimulation of atrial stretch receptors (which, when activated, cause cardioacceleration)  Management of bradycardia secondary to T1 to T4 blockade may include administration of low- dose epinephrine {Clark Albert, MD, personal communication}

 Non-availability of patient's consent, local infection or sepsis at the site of lumbar puncture, bleeding disorders, space occupying lesions of the brain, disorders of the spine and maternal hypotension.

 All surgical interventions below the umbilicus, is the general guiding principle:  Abdominal & vaginal hysterectomieshysterectomies  Laparoscopy Assisted Vaginal Hysterectomies (LAVH) combined with general anaesthesia Laparoscopy Assisted Vaginal Hysterectomies (LAVH) combined with general anaesthesia  Caesarean sections Caesarean sections  Hernia (inguinal or epigastric) Hernia  Piles fistulae & fissures Piles  orthopaedic surgeries on the pelvis, femur, tibia and the ankle orthopaedicpelvisfemurtibiaankle  nephrectomy nephrectomy  cholecystectomies cholecystectomies  trauma surgery on the lower limbs, especially if the patient is full-stomach trauma surgery on the lower limbs, especially if the patient is full-stomach  Open tubectomies Open tubectomies  Transurethral resection of the prostate Transurethral resection of the prostate

 Spinal anaesthetics are typically limited to procedures involving most structures below the upper abdomen. To administer a spinal anaesthetic to higher levels may affect the ability to breathe by paralysing the intercostal respiratory muscles, or even the diaphragm in extreme cases (called a "high spinal", or a "total spinal", with which consciousness is lost), as well as the body's ability to control the heart rate via the cardiac accelerator fibres.abdomendiaphragmheart rate  Also, injection of spinal anaesthesia higher than the level of L1 can cause damage to the spinal cord, and is therefore usually not done.L1

 Primary Reference:  Stoelting, R.K., "Local Anesthetics", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, pp ;Miller, R.D., Local Anesthesia, in  Basic and Clinical Pharmacology, (Katzung, B. G., ed) Appleton-Lange, 1998, pp