Spinal Anaesthesia Indications ( when to use ) Indications ( when to use ) Contraindications ( when not to use ) Contraindications ( when not to use ) Desired Effects Desired Effects Undesired Effects Undesired Effects Monitoring Monitoring Local Anaesthetic Drugs Used and Dosages Local Anaesthetic Drugs Used and Dosages Additive drugs used Additive drugs used Tips Tips

Spinal Anaesthesia : Indications ( when to use ) Suitable for surgeries below T-8 ( mid abdomen ) Suitable for surgeries below T-8 ( mid abdomen ) Examples include : Examples include : Cesarian section, hysterectomy, hernia repair, perineal surgery Cesarian section, hysterectomy, hernia repair, perineal surgery Bladder and lower urinary tract surgery, lower limb orthopaedic surgery and others …… It is considered the method of choice for Cesarian sections as it eliminates the need to manage high risk airways, and for TURP as it allows early recognition of symptoms of TURP syndrome It is considered the method of choice for Cesarian sections as it eliminates the need to manage high risk airways, and for TURP as it allows early recognition of symptoms of TURP syndrome

Spinal Anaesthesia : Indications ( when to use ) Considerations Considerations Duration of Surgery – even long acting agents regress after 2.5 – 3 hours despite epinephrine. Longest acting probably isobaric tetracaine / bupivicaine plus epi/fentanyl Duration of Surgery – even long acting agents regress after 2.5 – 3 hours despite epinephrine. Longest acting probably isobaric tetracaine / bupivicaine plus epi/fentanyl Site of Surgery – Some lower abdominal surgeries require higher blocks due to traction on pain sensitive visceral structures such as testicles and ovaries Site of Surgery – Some lower abdominal surgeries require higher blocks due to traction on pain sensitive visceral structures such as testicles and ovaries Hemodynamic Stability – spinals will cause a reduced venous return and blood pressure due to vasomotor paralysis Hemodynamic Stability – spinals will cause a reduced venous return and blood pressure due to vasomotor paralysis ( venodilatation )

Spinal Anaesthesia : Contra-iIndications ( when not to use ) Coagulopathic Patients – spinal needle may result in hematoma formation in pt on blood thinners, with low platelets ( generally < 50 as long as plts functional eg-not uremic ) or other coagulopathies. Coagulopathic Patients – spinal needle may result in hematoma formation in pt on blood thinners, with low platelets ( generally < 50 as long as plts functional eg-not uremic ) or other coagulopathies. –Wait atleast : –12 hours since last dose of heparin –24 hours since last dose of low molecular weight heparin –3-4 days since last dose of warfarin ( check INR ) –3-4 days since last dose of F10A inhibitors ( as long as renal function OK ) –7-10 days since last dose of platelet inhibitor ( cycloprigel, ticlidopine ) –ASA or Non steroidal anti-inflammatories OK !!!

Spinal Anaesthesia : Contra-indications ( when not to use ) Hypotensive or unstable patients – spinals reduce blood pressure Hypotensive or unstable patients – spinals reduce blood pressure Septic patients Septic patients Skin infection in path of needle Skin infection in path of needle Patients with fixed cardiac obstruction – Severe Aortic Stenosis or Pulmonary Hypertension – may not be able to compensate for venodilation Patients with fixed cardiac obstruction – Severe Aortic Stenosis or Pulmonary Hypertension – may not be able to compensate for venodilation Patients with seriously impaired ventricular function – these patients require adequate ventricular filling pressures to maintain cardiac output and spinals will decrease venous return Patients with seriously impaired ventricular function – these patients require adequate ventricular filling pressures to maintain cardiac output and spinals will decrease venous return Patients with Significant CNS Pathology – elevated ICP, arterio- venous malformations, spina bifida, ? previous spinal surgery and congenital problems Patients with Significant CNS Pathology – elevated ICP, arterio- venous malformations, spina bifida, ? previous spinal surgery and congenital problems

Spinal Anaesthesia : Desired Effects Spinals will result in a somatic and autonomic paralysis Spinals will result in a somatic and autonomic paralysis Typically sensory and motor function is abolished although one may lag behind the other Typically sensory and motor function is abolished although one may lag behind the other Dull sensation to pressure may persist but not painful Dull sensation to pressure may persist but not painful Generally, respiratory function is well maintained unless block is very high – loss of sensation of chest wall movement Generally, respiratory function is well maintained unless block is very high – loss of sensation of chest wall movement ( breathing ) may be alarming to patients Vasodilatation beneficial ( as with epidural ) for vascular procedures Vasodilatation beneficial ( as with epidural ) for vascular procedures Although insensate, patients may require some anxiolysis Although insensate, patients may require some anxiolysis

Spinal Anaesthesia : Undesired Effects Hypotension – leading to cardiac arrest Hypotension – leading to cardiac arrest Infection Infection Spinal Hematoma Spinal Hematoma Bradycardia - ( cardiac sympathetic T4 ) Bradycardia - ( cardiac sympathetic T4 ) Respiratory Distress – loss of abdominal and intercostal function in susceptible individuals Respiratory Distress – loss of abdominal and intercostal function in susceptible individuals Inadequate Anaesthesia – due to anatomical or post operative changes Inadequate Anaesthesia – due to anatomical or post operative changes Worsening of CNS pathology – bleed from AVM, aneurysm, brainstem herniation Worsening of CNS pathology – bleed from AVM, aneurysm, brainstem herniation Post Dural Puncture Headache – postural – rare over the age of 60 and minimized with the use of small ( 25-27g ) pencil point needles ( Whitacre ) Post Dural Puncture Headache – postural – rare over the age of 60 and minimized with the use of small ( 25-27g ) pencil point needles ( Whitacre ) Nerve Toxicity – with hyperbaric lidocine ( transient ), rare with others Nerve Toxicity – with hyperbaric lidocine ( transient ), rare with others –Use preservative free solutions only

Spinal Anaesthesia : Monitoring Standard monitoring applies Standard monitoring applies –Most catastrophic events will occur at 20 – 30 min but can occur up to 1 hour after the block – be vigilant !! BP, SaO2, ECG BP, SaO2, ECG Best way to determine dermatomal spread is light scratch or cold Best way to determine dermatomal spread is light scratch or cold T4 nipples T4 nipples T6costal margin T6costal margin T10umbilicus T10umbilicus

Spinal Anaesthesia : Drugs and Dosages Hyperbaric – heavier than CSF and migrates in CSF gravitationally Hyperbaric – heavier than CSF and migrates in CSF gravitationally Typically pools in thoracic kyphosis resulting in higher block Typically pools in thoracic kyphosis resulting in higher block T4-T6 usual – useful for mid and lower abdominopelvic procedures T4-T6 usual – useful for mid and lower abdominopelvic procedures Bupivicaine typically 12 – 15 mg less in pregnancy, obesity Bupivicaine typically 12 – 15 mg less in pregnancy, obesity Tetracaine diluted in D10W – mg Tetracaine diluted in D10W – mg Perineal ( saddle ) block if left sitting 1min post injection Perineal ( saddle ) block if left sitting 1min post injection

Spinal Anaesthesia : Drugs and Dosages Isobaric - Less cephalad spread – medication diffuses nearer injection site Isobaric - Less cephalad spread – medication diffuses nearer injection site Useful for lower extremity procedures Useful for lower extremity procedures Bupivicaine 12.5 – 20 mg lasts 3 – 3.5hrs Bupivicaine 12.5 – 20 mg lasts 3 – 3.5hrs Tetracaine diluted with saline 15 – 20 mg lasts 3 – 3.5 hrs Tetracaine diluted with saline 15 – 20 mg lasts 3 – 3.5 hrs Lidocaine 40 – 60 mg lasts 1 – 1.5 hrs Lidocaine 40 – 60 mg lasts 1 – 1.5 hrs 2-Chloroprocaine 40 – 60 mg lasts 45 min – 1 hr 2-Chloroprocaine 40 – 60 mg lasts 45 min – 1 hr

Spinal Anaesthesia : Additive drugs used All drugs must be preservative free All drugs must be preservative free Epinephrine 5 mcg/ml prolong lidocaine block ; less with bupivicaine Epinephrine 5 mcg/ml prolong lidocaine block ; less with bupivicaine Fentanyl 20 mcg potentiates block and may allow for less local anaesthetic Fentanyl 20 mcg potentiates block and may allow for less local anaesthetic Morphine 200 – 300 mcg provides long lasting analgesia but beware delayed respiratory depression ( 8 hrs ) and troublesome side effects such as pruritus and nausea Morphine 200 – 300 mcg provides long lasting analgesia but beware delayed respiratory depression ( 8 hrs ) and troublesome side effects such as pruritus and nausea

Spinal Anaesthesia : Tips Sitting positon preferred – if lateral, ensure good fetal position Sitting positon preferred – if lateral, ensure good fetal position Only use 22g on patients >60 or if urgent, or difficult Only use 22g on patients >60 or if urgent, or difficult –Otherwise 25 – 27 g through introducer to minimize PDPH –The smaller the better –Whitacre or Sprotte needles if possible Sedation helpful Sedation helpful Small dose ketamine useful for positioning # hip in lateral position Small dose ketamine useful for positioning # hip in lateral position Paramedian approach useful Paramedian approach useful