Intra cranial pressure and Anaesthesia by Prof. mridul M. Panditrao
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This document discusses the management of increased intracranial pressure and its implications for anesthesia. It covers the physiology of intracranial pressure regulation, factors that can increase pressure, methods for monitoring pressure, complications of monitoring, and medical and surgical interventions to reduce pressure. It also addresses how anesthesia agents can impact intracranial pressure and the importance of preoperative optimization of patients at high risk for postoperative complications from increased intracranial pressure.
Intra cranial pressure and Anaesthesia by Prof. mridul M. Panditrao
- 1. MANAGEMENT OF RAISED ICP AND ANAESTHETIC IMPLICATIONS
- 2. Dr. M. M. PANDITRAO PROFESSOR/ HEAD & I/C SICU DEAN of Faculty of Medicine DEPT.OF ANAESTHESILOGY & CRITICAL CARE Pad. Dr. DY PATIL MEDICAL COLLEGE, HOSITAL & RESEARCH CENTER ( Dr. DY PATIL UNIVERSITY ) PIMPRI, PUNE 411018 MAHARASHTRA
- 3. Introduction • Physiology of ICP Maintenance Cranium: A Box with only one opening Opening at the base No possibility of expansion Primary Function: Protection of brain Also maintain an equilibrium
- 4. Cranium
- 5. Intracranial Contents • Brain 80 – 85 % • CSF 8 – 12 % • Cerebral blood volume 5–8% • Total Intra cranial volume 1500 ± 100ml
- 6. Compensatory Mechanisms • Autoregulation of cerebral blood flow • Regulation of CSF • Regulation with help of metabolic changes
- 7. Monro-Kellie Hypothesis Pathologic States that increase the volume of one component necessitate decrease in the volume of another to maintain normal Intra-Cranial Pressure
- 8. INTRA CRANIAL PRESSURE (ICP) • Measure of CSF Pressure within Cranium • Normal range 5 – 15 mm Hg
- 10. CONSEQUENCES • Internal herniation:- Temporal lobe is pushed down though Tentorium incisura • External herniation:- Cerebellar tonsills/ peduncle herniate through foramen magnum → Compressing over IV ventricle → ↓CPP → Death == “CONING”
- 11. CEREBRAL PERFUSION PRESSURE (CPP) • Effective pressure that allows the perfusion of blood through the brain • CPP = MAP – ICP • Mean arterial pressure (MAP) = DP+ (SP-DP) • DP + PP/3 3 • (ICP ≈ CVP) • CPP ≈ MAP – CVP
- 12. CEREBRAL BLOOD FLOW • Normal CBF 45 – 50 ml / 100 gm / min • Range 20 ml / kg / min to 70 ml / kg / min • CBF Highest Frontal region • CBF Medium Parietal region • CBF Lowest Temporal area
- 13. HAEMODYNAMIC AUTO REGULATION • Cerebral Autoregulation • Normal range MAP 50 – 150 mm Hg • In Head injured ~~ Failure of autoregulation • CBF = < 20ml / kg /min. • Adverse effect on ICP
- 14. FACTORS EFFECTING C.B.F. • Hypoxia • Hypercapnea • Inhalational anaesthetic agents • Acidosis
- 15. METABOLIC AUTOREGULATION OF C.B.F. • Hypercapnea • “Luxury perfusion syndrome”
- 16. METABOLIC AUTOREGULATION OF C.B.F. (Cont.) • “Steal syndrome” • “Inverse steal” • ↑ CBF – PaCO2 drops below 50 mm Hg
- 17. INCREASED I.C.P. • ICP <15 mmHg – Intracranial hypertension • Acute • Chronic ICP in mmHg Normal 5 – 15 Mild 16 - 20 Moderate 21 - 30 Severe 31 - 40 Very Severe 41 & Above
- 18. PATHO-PHYSIOLOGY OF INCREASED I.C.P. • CPP α CBF • CPP α 1/ICP • ↑ICP → ↓CBF, ↓Blood volume, ↑CO2
- 19. FACTORS CAUSING INCREASED I.C.P. • Cerebral Oedema Vasogenic Cytotoxic oedema Hypoxemia Hyponatremia/ Water Intoxication Post-Cardiac Arrest Inflammatory—Meningitis/Encephalitis Interstitial oedema • Intra Cranial Space Occupying Lesions • Enlarged ventricular system • Pneumocephalus • Increase in C.B.F. • Impaired cerebral venous drainage
- 20. FACTORS CAUSING INCREASED I.C.P. IN CHILDREN Neonates/Infants • Secondary cerebral oedema to peri-natal hypoxia or trauma • Congenital hydrocephalus Older Infants/Toddlers/Children • Meningitis • Brain tumors (Infra tentorial) • Pseudo tumor cerebrii • Trauma • Reye’s syndrome
- 21. ASSESSMENT OF ICP • Thorough clinical assessment • “WARNING SIGNS”: Confusion, agitation, restlessness, aggressiveness Personality changes Glasgow Coma Score (GCS)
- 22. GLASGOW COMA SCORE Findings Score Findings Score 1) Eye opening 3)Best motor response Spontaneous 4 Obeys Commands 6 To voice 3 Localizes pain 5 To Pain 2 Withdraws 4 None 1 Abnormal flexion 3 2) Best verbal response Extension 2 None 1 Oriented 5 Confused speech 4 Prognostic value as per Inappropriate words 3 GCSScore Percentage Incomprehensible sounds 2 GCS 3/ less 100 None 1 GCS 3 – 5 60 – 84 GCS 6 – 8 36 – 46
- 23. I.C.P. MONITORING (Cont.) • Pupillary light reflex • Corneal reflex • Occulocaloric reflex • Occulocephalic reflex
- 24. CUSHING’S TRIAD • ↑ Systolic blood pressure • Widening of pulse pressure • Bradycardia • Projectile vomiting • Irregular respiratory pattern
- 25. INTRACRANIAL PRESSURE MONITORING • Def: • Ventricular system • Sub-arachnoid space • Epidural space • Brain parenchyma
- 26. METHODS OF I.C.P. MONITORING • Intraventricular catheter • Subarachnoid screw or bolt • Epidural sensor
- 28. ICP WAVE FORMS • A, B, & C waves • Factors influencing waves Systolic blood pressure Alterations in respiration Deteriorating neurological status • Components of waves P1 (upward spike) P2 (tidal wave) P3 (small notch)
- 30. ICP WAVE FORMS (CONT.) A waves • Plateau waves • Most life threatening • Seen in 5-20 min intervals • Increased I.C.P. • CPP compromised • Amplitude 50 – 60 mmHg
- 32. ICP WAVE FORMS (CONT.) B waves • Saw toothed appearance • Occur every 30 – 60 sec • Amplitude 25 – 50 mmHg • Indicates Unstable ICP& unconsciousness • Stimulation ↑ amplitude
- 34. ICP WAVE FORMS (CONT.) C waves • Lowest amplitude • Occur in 4 – 8 min intervals • Never get elevated >20 – 25 mmHg • Clinical significance unknown
- 36. COMPLICATIONS OF ICP MONITORING • Infection • intracranial hemorrhage or haematoma • CSF Leakage • Mechanical failure or blockage • Over drainage of CSF
- 37. MANAGEMENT OF INCREASED I.C.P. “ABC” APPROACH (U.K.) • Airway • Breathing • Circulation • Drugs • Exposure • Fluids • Glucose • Haematology • Investigations
- 38. MANAGEMENT OF INCREASED I.C.P. (U.S.A.) • Airway • Breathing • Circulation • Disability • Exposure • Fluids • Glucose • Haematology • Investigations
- 41. SECOND TIER THERAPY • Optimized hyperventilation • Barbiturate coma • Decompressive craniectomy
- 42. OPTIMIZED HYPERVENTILATION • Increase minute ventilation • Maintain PaCO2 below 30 mm Hg • Monitor Jugular venous oxygen saturation Normal range 65 – 75%
- 43. BARBITURATES COMA Pentobarbitone Sodium • Loading dose:- 10 mg / Kg IV over 30 min • Infusion :- 5 mg / Kg / hour for 3 hrs • Maintenance :- 1 – 3 mg / Kg / hour, Titrated to burst suppression on continuous bedside EEG • Suppresses CMR02 & ↓ICP • Disadvantages
- 44. DECOMPRESSIVE CRANIECTOMY • Alternative therapy • Allow the brain to swell in a fashion not harmful to it • Uni / bilateral Fronto-Temporo-Parietal Craniectomies
- 45. INTERVENTION FOR REDUCING INCREASED ICP Preliminary Management • Maintain the patient’s head in midline to facilitate bilateral blood flow • Maintain head of bed (H O B) at 30 – 40° to facilitate venous drainage with minimal effect on arterial pressure • Avoid all the activities which will increase / worsen ICP excessive light / noise / interference / painful stimuli Suctioning • Decrease hyperthermia if present
- 46. INTERVENTION FOR REDUCING INCREASED ICP (Cont.) • Strict intake / output balance with specific stress on over hydration which can lead to cerebral edema. • Electrolyte monitoring: to avoid Na+ disturbances- hyper as well as hyponatremia, hypokalemia – especially if on diuretic therapy. • Glucose level monitoring to avoid hypoglycemia. • Avoidance of severe hypocapnia to maintain level of hyperventilation so as to maintain PaCO2 between 25-35 mmHg (≈ 30± 2 mmHg).
- 47. INTERVENTION FOR REDUCING INCREASED ICP (Cont.) Medical management • Anticonvulsant therapy for seizures. • DIURETIC therapy. • Mannitol, Glycerol, Urea, Hypertonic saline. • “Barbiturate Coma” Therapy. • 50% Dextrose for hypoglycemia. • ICP monitoring & drainage if required. • Surgical decompression ( Craniotomy ). • Controversial Corticosteroid Therapy.
- 48. DIURETIC THERAPY • Principle • Osmotic diuretic • Disadvantages • Mannitol 0.5 to 1.5 gm/kg I.V 4-5 hourly • Glycerol 1-2 gm/kg orally (loading),0.5 gm/kg every 4 hourly • Urea: not exceeding 120 gm/day • Hypertonic saline • Loop Diuretics
- 49. ANAESTHETIC MANAGEMENT OF PATIENTS WITH INCREASED I.C.P. • Polytrauma • Head injury • Long bone injuries • Intra abdominal visceral trauma
- 50. PRE-OPERATIVE ASSESSMENT AND PREPARATION “Patients Undergoing surgery at high risk for post-operative complication and death” • Poor pre-operative physiological condition • Age • Type surgery they are supposed to undergo
- 51. SHOEMAKER et al CRITERIA • Current /previous severe cardio respiratory illness • Acute abdominal catastrophe with haemodynamic instability • Acute renal failure • Severe multiple trauma (more than 3 major organs involved or more than 2 system or surgical opening of more than 2 body cavities) • Elderly patients (70 or more years of age)
- 52. SHOEMAKER et al CRITERIA (Cont.) • Shock (MAP < 60 mmHg & urine out put < 0.5 ml/kg/hr) • Acute respiratory failure • Evidence of septicemia, colo-rectal injury or peritoneal soiling, intra-abdominal surgery • Patients undergoing prolonged surgery > 1½ hrs. • Emergency surgery • Inexperienced surgeon • Lack of post operative I.C.U./critical care facility
- 53. GOAL DIRECTED CARDIO-RESPIRATORY OPTIMIZATION • Cardiac index. • Oxygen delivery. • Oxygen consumption continue till • Base Deficit ~~~ normal • Blood Lactate ~~~ normal • Mixed SVO2 > 70%
- 54. ANAESTHETIC CONSIDERATIONS • Inhalational drugs • Nitrous Oxide • Intravenous Induction agents • NMBDS • Opioids
- 55. Summary • I.C.P. is an important parameter • Physiology • Pathology related to increased ICP • Monitoring of ICP • Interaction between ICP and anaesthetic agents • Anaesthesiologist as Peri-operative Physician