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Head Injury: An Anaesthesiologist’s Perspective

Head Injury: An Anaesthesiologist’s Perspective. Presenter: Dr. Ashish Chakravarty MD Student, 2 nd year Moderator: Dr. Kavita Sharma Professor, Dept. Of Anaesthesiology and Intensive care, MAMC. www.anaesthesia.co.in anaesthesia.co.in@gmail.com. Classification Of TBI.

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Head Injury: An Anaesthesiologist’s Perspective

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  1. Head Injury: An Anaesthesiologist’s Perspective Presenter: Dr. Ashish Chakravarty MD Student, 2nd year Moderator: Dr. Kavita Sharma Professor, Dept. Of Anaesthesiology and Intensive care, MAMC www.anaesthesia.co.inanaesthesia.co.in@gmail.com

  2. Classification Of TBI • PRIMARY INJURY #Contact #Inertial *Rotational: Diffuse *Translational: Focal • SECONDARY INJURY: Due to inflammatory mediators as a result of ischemia

  3. History • Time since injury • h/o LOC • h/o vomiting • ENT bleed or dripping of watery fluid from the ear or nose • h/o seizures in the past and if on treatment • h/o any other illness and treatment

  4. Response and ABC GCS, and classify TBI according to GCS: 13-15 Mild 09-12 Moderate <9 Severe Lacerated wd, open # or depressed # ENT bleed or CSF rhinorrhoea or otorrhoea Pupil size and rxn. Maxillary or Mandibular disruption Cervical spine CVS : HR, BP Resp: Tachypnoea, Crepts & Ronchi, Decreased air entry, Paradoxical movt. Abdominal girth Blood at the urethral meatus Bony injuries of the limbs Examination

  5. Immediate: X- ray: *cervical spine (lat.) *chest *pelvis CT Scan: To identify: *the nature of insult *if the ICP is raised *pneumocephalus *classify TBI Others: *hemogram *blood sugar *bleeding profile *KFT *S.E & S. osmol *ECG *ABG Investigations

  6. Indications of CT Scan • Severe TBI • Moderate TBI • Any GCS <15 • h/o LOC anytime even if GCS is 15

  7. Management • Scenarios: 1.In the ER 2.In the OT for craniotomies for other surgeries 3.In the ICU 4.While transporting the patient 5.h/o head injury, with its long term sequele, for some other surgery

  8. General principles of management • 1st priority: Airway – patency, protection, proper ventilation • GCS <=8 will always require ventilation • GCS >8 also may require ventilation owing to trauma related cardio-pulmonary dysfn. • Anticipate: • Full stomach, irrespective of NPO status • Head & neck injuries: skull base #, facio-maxillary, loose teeth, blood in airway, disruption of laryngo-arytenoid cartilage, cervical spine injury • Injury to the thorax leading to hypoxemia • Injury to the abdomen and leading to hypovolemia • Increased ICT • Combative patient

  9. …contd • Establishment of an airway: • Route: preferably oral • Tube: flexometalic or pvc • Tecnique: rapid sequence + MIST with hypnotic and muscle relaxant • Emergency airway devices must be at hand • 2nd priority:Maintenance of CPP: # CPP= MAP- ICP (aim: >60 mm Hg)

  10. …contd. MAINTENANCE OF MAP: 1) Fluid management: general principles: a) maintain normovolemia: *avoid dehydration, *correct shock aggressively b) avoid decrease in s. osmolarity: *avoid fluids providing free water (D-5 & D-10) *for ongoing free water loss use N/2 saline *for replacing iso-osmolar losses use NS / RL *for significant blood losses and in case of multiple trauma alternate each litre of NS with RL Role of colloids and hypertonic saline??!

  11. …contd. • B.P Management: • Edinburgh concept of ideal CPP (>70 mm Hg) • Birmingham concept of induced HTN • Lund concept of dehydration • Common to modification of these concept is to maintain a CPP b/w 60-70 mm Hg for a period of at least 48-72 hrs. when the CBF is low. In case of SAH this has to continue for a period of 10 days due to second period of low CBF due to vasospasm.

  12. …contd. • MAINTENANCE OF ICP: (< 20 mm Hg) • Monro Kelly doctrine: ICP is proportionally equal to the sum of vol of intracranial contents Control measures Contents Cells Surgical removal Diuertics- osmotic and loop Steroids Fluid (intra and extra cellular) CSF Decreased production Drainage Arterial blood Decreased CBF Venous blood Improved drainage

  13. Indications of ICP Monitoring • Severe TBI • Moderate TBI if abnormal CT • In comatose even if normal CT • Even in normal CT if 2 or more of the following: • Age > 40 yrs. • SBP < 90 mmHg • U/L or B/L posturing • SOL esp. lesions in the fronto-temporal or medial temporal regions • For Rx of Cushing’s reflex

  14. ICP Control Algorithm • R/O causes of decreased venous drainage • Sedation & paralysis • Intermittent CSF drainage • Mannitol • Decrease PaCO2 to 30 mm Hg ( prophylactic CI) • CT Scan and surgical intervention if needed • If surgical intervention not suggested by CT, go for high dose barbiturate until burst suppression • Induced hypothermia for 24-48 hrs. • Decompressive craniectomies in < 40 yrs old

  15. During surgery • Position of the patient 15-30º head up. • Premed: Short acting opioids if needed, consider problems of opioids • Induction agent: I.V agents, except ketamine • Maintenance: order of preference: IV agents> sevo>des>iso • Muscle relaxants: administer by watch; use NM monitor, not ETCO2; avoid histamine releasers. • Anticonvulsants: head injury, SAH, SDH, cortical incisions, retractors are all cortical irritants. Phenytoin to be administered for 7 days • N2O to use or not ??! Mannitol, how much??! • How much PaCO2 to be maintained??! • Role of steroids??!

  16. N2O and Mannitol controversy • N2O should not be used if significant pnemocephalus or VAE • Can be started after dural opening • Should be used up to the point of dural closure • Mannitol dose: 0.25 – 1 g/kg • Rebound swelling: Watch for brain edema, s.osmolality, S.Na+ • Use intermittently • Add a loop diuretic

  17. …contd. • Monitoring: • Preinduction: ECG, NIBP / IBP, SpO2, ETCO2 • Postinduction: Urine o/p, CVP, RBS, Temperature, SE, S. osmolarity, Blood loss, Inspection of the field, Surgeons assessment of the tightness of brain, Head position, Kinking of the ETT or loosening of tapes. • Other ‘trendy’ monitors: Sjvo2, Brain tissue PO2 • What if during a surgery close to a major venous sinus there is a sudden fall in BP with a rise in CVP, and ETCO2 falling to 0? • What if ECG shows inverted T waves? • Blood sugar to be maintained at what level?

  18. …contd. • Emergence from anaesthesia: • Decide whether to extubate • GCS<=8 - better not to extubate • GCS>8 – may be discussed with the surgeon • Smooth extubation • Hazards of coughing prior to extubation: Raised ICP, Bleeding, Recurrence of CSF rhinorrhoea • Hazards of coughing after extubation: Same as above + tension pneumocephalus if Sx for CSF Rhinorrhoea • Methods to decrease coughing: opioids and codein related compounds, withold reversal as long as possible, boluses of propofol and nitrous till the end of DRESSING, lignocaine 1.5 mg/kg at the start of DRESSING • To prevent rise in BP: NTG, SNP, Esmolol may be continued, prevent shivering, pain, and bladder distension. • No role for deep extubation • Tension pneumocephalus can cause delayed recovery, and severe head ache postop.

  19. Special considerations in the ICU • Respiratory System: likely problems :- • Nosocomial / ventilator associated pneumonia • Bronchoconstriction and absent HPV • Neurogenic pulmonary edema • ARDS • Fat and pulmonary embolism • Diaphragmatic paralysis: transient, permanent

  20. …contd. • CVS problems: • ECG changes: bradycardia, short QT, ST elevation, nodal rhythm, T waves amplification and inversion, Atrial fibrillation…even asystole • Due to vagal stimulation: Central autonomic stimulation at cortical, hypothalamic, and brain stem levels • Neurogenic shock (during change of bedding) • Cardiogenic shock • Effect of lo’ flo’ state on myocardial fn. • Sometimes elevated CK-MB and subendocardial hmgs. Might preclude consideration of these patients for transplant

  21. …contd. • Hematological problems: • Anemia: due to blood loss or nutritional • Coagulation abnormalities: • Good correlation b/w severity of trauma and decrease in platelets, clotting factors II and V, and plasminogen; and an increase in FDP. • Brain richest source of tissue thromboplastin after lung. Even mild cerebral trauma may lead to DIC. • Direct hypothalamic stimulation can lead to decreased clotting factor VIII • Abrupt rebound antifibrinolysis: adrenergic hyperactivity may trigger hypercoagulability. • Microthrombi may cause end-organ damage and increase in PVR • DVT due to immobility

  22. …contd. • Gastrointestinal problems: • Cushing’s ulcer: due to increased ICP & Steroids • Hypovolemic shock + sympathetic overactivity may lead to mucosal ischemia and erosion • Steroids retard the rate of renewal of surface epithelial cells and mucous production • GI hypomotility • Nutrition: • BMR increases by a factor of 1.4 • Increased requirement of Branched Chain Amino Acids (Val, Leu, Isoleucine) • Increased Nitrogen wasting • Enteral feeding is preferred • Where there is concern about regurgitation and silent aspiration, feeding jejunostomy is advocated

  23. …contd. • Glucose metabolism and Nonketotic Hyperosmolar Hyperglycemic Coma: Causes: • Adrenergic hyperactivity: gluconeogesis, glycogenolysis and inhibition of insulin release • Anti-insulinic effect of GH • Steroids: gluconeogesis, glycogenolysis, insulin resistance, exhaustion of ß cells • Phenytoin: glycogenolysis, insulin resistance • Others: thiazides, glycerol • Contributors of NHHC: above + prolonged mannitol Rx, Hyperosmolar feeding, inadequate hydration NHHC causes intracellular dehydration of brain

  24. …contd • Management: • RBS level to be kept below 150mg% • NHHC with Na and water deficit: NS • NHHC after Na & water deficit correction with stable BP & urine o/p: ½ NS • Large doses of Insulin should not be given in NHHC until correction of Na and water has been done otherwise rapid decrease in osmolality can cause cerebral edema • S.K+ is usually low in NHHC. K+ supplementation may be required

  25. …contd. • Hyponatremia: • May be associated with SIADH • May aggravate cerebral edema, and weakness and rhabdomyolysis –difficulty in weaning • Rx: 3% saline, frusemide, and free water restriction, demeclocyclin and lithium for SIADH • Na deficit: 0.6 x kg x [140 – Na+ ] • Rapid correction: 4 commandments: • U’ll not correct > 1 – 2 mEq/L/hr • U’ll not correct >12 mEq/L in 24 hrs • U’ll not correct >24 mEq/L in 48 hrs • U’ll not correct >130 mEq/L

  26. …contd. • Hypernatremia: • May be associated with DI • May lead to seizures, ICH and hyperreflexia • Rx: hypotonic fluids, and loop diuretics or dialysis • TBW Deficit: 0.6 x kg [ 1- (140/Na+) ] • Infections: • Ventriculitis & meningitis • Pulmonary: broncho-alveolar hygiene, gastric acidity • Maxillary sinusitis and otitis media: due to ETT or: RT • UTI • Sepsis • Hyperthermia detrimental for ICP

  27. …contd. • Sedation • GCS for assessing neurological status not for sedation • Use Ramsay Sedation Scale or Sedation Agitation Score instead • Midazolam and propofol ideal agents • Problems with propofol: • Hypertriglyceridemia if used for >3 days • Metabolic acidosis • Rhabdomyolysis and cardiovascular collapse • Problems with prolonged use of relaxants: • Critical illness myopathy • Problems with morphine: • Histamine release • Pupillary constriction • Depression of immune response

  28. While intra or inter hospital transport • Head-up position • Maintain airway patency & proper ventilation • Continue inotropes if on any • Monitor vitals

  29. Considerations for those with h/o head injury for some other surgery • R/O clinical features of ICSOL and raised ICT • Record any neurological deficits: MLC • If associated with myopathies: use scoline cautiously • If on Rx for seizures: obtain neurological opinion for feasibility of surgery, and continue the medications till the day of surgery • Drugs with epileptogenic potential eg. ketamine,, atracurium, flourinated inhalational agents esp. Enflurane, Sevo> Iso, methohexitone • Aspiration prophylaxis

  30. THANK YOU www.anaesthesia.co.inanaesthesia.co.in@gmail.com

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