Monitoring in anaesthesia ro

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1. MONITORING IN ANAESTHESIA NUR FARRA NAJWA BINTI ABDUL AZIM 082015100035

2. INTRODUCTION Monitoring is important to prevent anaethesia complication Sophisticated monitor available, only to aid not to fully dependent on them Anaesthetist vigilance is the best

3. BASIC MONITORING

4. BASIC MONITORING- Clinical Monitoring Pulse rate Color of skin Blood pressure Inflation of chest Precordial and esophageal stethoscopy Signs of sympathetic over activity Urine output (>0.5ml/min)

5. ADVANCE MONITORING- instrumental monitoring

6. 1. CARDIOVASCULAR MONITORING

7. 1.ECG Mandatory monitor to detect : Arrhythmia – lead II Ischemia – lead V5 cardiac arrest.

8. 2. NIBP Measure blood pressure at set intervals automatically by automated oscillometery . Cuff size should cover 2/3 of arm Small cuff for children Too large (underestimate) Too small (over estimate)

9. 2. SEMI-INVASIVE (TEE)

10. Transesophageal Echocardiography (TEE) Most sensitive to detect any wall motion abnormality ischemia , valvular dysfunction, air embolism

11. 1. IBP Required in patient mandates for beat to beat monitoring Gold standard Accuracy measure the difference in IBP & NIBP not more than 5-8mmHg Radial Artery Brachial Artery Femoral Artery Dorsalis Pedis Artery

12. Allen’s Test Normal - <7s Borderline – 7-14s >15s – contraindicated

13. > Cannulation complication Arterial injury, spasm, distal ischemia Thrombosis, embolization Sepsis Tissue necrosis Fistula and aneurysm formation *prevention : continuous flush with/out heparin

14. 2. CENTRAL VENOUS PRESSURE MONITORING (CVP)

15. > INDICATION Major surgeries where large fluctuations in haemodynamics are expected. Open heart surgeries . Fluid management in shock. As a venous access. Parenteral nutrition. Aspiration of air embolus. Cardiac pacing. Normal CVP is 3 to 10 cm of H20 (or 2-8 mmHg). In children CVP is 3 to 6 cm of H20. CVP more than 20 cm of H2O indicates right heart failure .

16. > Technique of CVP Catheterization (Through Internal Jugular Vein) Seldinger technique Patient lies in Trendelenburg position – to decrease chance air embolism The cannula with stylet is inserted at the tip of triangle formed by two heads of sternomastoid and clavicle. The direction of needle should be slightly lateral and towards the ipsilateral nipple. Once the internal jugular vein is punctured. Stylet is removed and a J wire is passed through cannula Now the CVP catheter is railroad over the J wire The tip of catheter should be at the junction of superior vena cava with right atrium – 15 cm from entry point

17. > CVP is Increased in : Fluid overloading Congestive cardiac failure. Pulmonary embolism Cardiac tamponade Intermittent positive pressure ventilation with PEE P Constrictive pericarditis Pleural effusion Hemothorax Coughing and straining

18. > CVP is Decreased in : Hypovolemia and shock Venodilator Spinal / epidural anaesthesia General anesthesia – by causing vasodilatation Low CVP + low BP = Hypovolemia High CVP + low BP = pump failure

19. X ray chest is performed to check the position of catheter and to exclude pneumothorax Complication Air embolism Thromboembolism Cardiac arrhymias Pneumothorax/ haemothorax /chylothorax Cardiac perforation/cardiac tamponade Sepsis – late complication Trauma to brachial plexus, carotid A,phrenic N,airway

20. 3. Pulmonary Artery Catheterization It is reserved only for very major cases in severely compromised patients because cost, technical fea sibility, complications Swan Ganz catheter - It is balloon tipped and flow directed by pressure recording,pressure tracing and catheter tip Indicated by sudden rise in diastolic pressure

21. > Indication : Measuring cardiac chambers pressure (except left ventricle). Calculating cardiac output Measuring pulmonary artery occlusion pressure (PAOP) Taking sample for mixed venous blood Titration of fluid infusion

22. > Complication Minor arrhymias – most common Pulmonary artery rupture Severe arrhymias Death

23. 2.RESPIRATORY MONITORING

24. Respiratory monitoring Pulse oximetry Capnography Blood gas analysis Lung volumes Oxygen analysers Airway pressure monitoring Apnea monitoring

25. 1. Pulse oximetry Oxygen saturation – SpO2 Normal SpO2 - 97 – 98 % Probe is applied at : finger nail bed, toe nail bed , ear lobule, tip of nose Uses : detection of hypoxia intra/post operative

26. > Errors Carboxyhaemoglobinemia Methhemoglobinemia Anemia Hypovolemia and vasoconstriction Nail polish Shivering spO2 below 60% Skin pigmentation Dyes

27. 2. Capnography It is the continuous measurement of end tidal (expired) carbon dioxide (ETCO2) and its waveform. Normal : 32 to 42 mmHg (3 to 4 mmHg less than arterial pCO2 which is 35 to 45 mmHg ). Principle : infrared light absorbed by carbon dioxide Important and sensitive monitoring

28. 3. Blood Gas Analysis Precaution Glass syringe is preferred for sampling Syringes should be heparinized Samples should be stored in ice Sample from radial or femoral Important in Thoracic surgery Hypothermia Hypotensive anaesthesia

29. Normal values on room air pH - 7.38 to 7.42 Partial pressure of oxygen ( p02 ) - 96 to 98 mmHg Partial pressure of carbon dioxide ( pCO2 ) - 35 to 45 mmHg Bicarbonate ( HCO3 ) - 24 to 28 mEq /L Oxygen saturation ( SpO2 ) - 95 to 98% Base deficit -3 to + 3

30. Cont Mixed venous oxygen in the best indicator of cardiac output i.e., tissue oxygenation Arterial oxygen is the better indicator of pulmonary function. pO2 -40 mmhg pCO2 -46 mmhg Oxygen saturation -75%

31. > Others LUNG VOLUMES – spirometer OXYGEN ANALYSERS Monitor actual value oxygen delivered Fitted in inspiratory in limb of breathing circuit Useful in closed circuit (use low flow oxygen) AIRWAY PRESSURE MONITORING It should less than 20 – 25cm H2O Low pressure – disconnection High pressure – obstruction in tube or circuit and bronchospasm

32. 4. APNEA MONITORING (MONITORING of RESPIRATION) Apnea is cessation of respiration for more than 10s. Intubated patients Capnography - Most sensitive and cost effective to detect apnea Airway pressure monitor Non intubated patients Monitoring the airflow at nostrils (acoustic probe) Detection of chest movements Impedence plethysmography – chest is encircled by a coil Transthoracic impedence pulmonometery For intubated and non intubated patient Pulse oximeter

33. 3. TEMPERATURE MONITORING

34. > Indication High incidence of intra-operative hypothermia Usually in Cardiac surgery Infant Children Adult with burns Febrile patient Malignant hyperthermia patient

35. > Temperature monitoring Core temperature monitoring sites : Esophagus Pulmonary artery Nasopharynx Tympanic membrane – most accurate for brain temperature

36. 1. Hypothermia Hypothermia may be defined as core temperature less than 35 ℃ . Mild : 28 – 35 ℃ Moderate : 21 – 27 ℃ Severe : < 20 ℃ Most common thermal perturbation seen in anaesthesia because : Most anaesthetics are vasodilators , causing heat loss and hypothermia Cool room temperature Cold intravenous fluids. Evaporation

37. > Systemic effects of hypothermia CVS Bradycardia Hypotension Ventricular arrhythmias if temperature is less than 28°C Respiratory system Respiratory arrest below 23°C O2 dissociation curve is shifted to left Blood Increased blood viscosity and platelet count

38. Acid base balance Increased solubility of blood gases Acidosis – increased lactic acid production d/t blood stasis Kidney Decresed GFR No urine output at 20 °C Endocrine system Decreased adrenaline and nor-adrenaline Hyperglycemia

39. > Treatment of lntraoperative Hypothermia Warm intravenous fluids Increase room temperature : The ideal operation theatre temperature for adults is 21°C and for the children 28°C Cover the patient with blankets Forced warm air by a special instrument ( Bair Hugger airflow device)

40. > Uses of Induced Hypothermia Brain protection in cardiac arrest or neurovascular surgeries. Brain can be protected for 10 minutes at 30°C For tissue protection against ischemia in cardiac surgeries done on heart lung machine

41. 4. NEUROMUSCULAR MONITORING

42. 1. Neuromuscular monitoring Adductor pollicis ( ulnar nerve) Others : Orbicularis oculi, Median nerve, Posterior tibial nerve , Peroneal nerve Required for : Myasthenia gravis Duchenne’s muscular dystrophy Train of four (TO4) is the most useful method for clinical monitoring. In this 4 stimuli, each of 2 Hz for 2 sec are given and recordings are taken. Normal : amplitude height of fourth and first response will be the same. T4/T1 = 1

43. Usage of depolarizing muscle relaxant – all 4 amplitude will be decrease Non depolarizing muscle relaxant – first there will be decrease in T4/T1 ratio followed by fading which means T4 response will disappear first then T3 and so on. Assess reversal Ratio 0.7 indicate adequate reversal Recovery guaranteed at ratio 0.9 Usefull in dx phase II block (patient on Sch show fading its pathgonominic of phase II block)

44. > Other stimuli used for neuromuscular monitoring Single twitch Tetanic stimulation Post tetanic facilitation Double burst stimulation (DBS 3,3 )

45. 5. CENTRAL NERVOUS SYSTEM MONITORING

46. MONITORING DEPTH OF ANAESTHESIA Clinically : Signs and symptoms of light anaesthesia are: Tachycardia. Hypertension. Lacrimation. Perspiration. Movement response to painful stimuli. Tachypnea , breath holding, coughing, laryngospasm, bronchospasm. Eye movements. Preserved reflexes

47. EEG Patient evoked response Bispectral index Entropy – detection of abnormalities in EEG at higher concentration of anaesthetic agents

48. Evoked response Assessing the integrity of neuronal tissues during surgeries Somatosensory evoked pontential ( SSEP) Any surgeries that can compromise vascular supply of sensory tract Spine surgeries, repair of thoracic and abdominal aorta aneurysm, brachial plexus exploration and surgery of brain area Auditory evoked potential (AEP) For procedures involving auditory pathways Resection of acoustic neuroma and posterior fossa surgeries Visual evoked potentials (VEP) For procedures involving visual tracts Optic glioma, pituitary tumours

49. Electrocephalogram (EEG) Other than measure depth of anesthesia , EEG also can asses cerebral ischemia during neurovascular surgeries – carotid endarterectomy Effect of anesthetic agents and modalities on EEG All inhalational and intravenous anesthetic agents produces biphasic pattern on EEG Lower dose – causing excitation( high frequency and low amplitude waves). High dose - causing depression (high amplitude and low frequency waves)

50. 6. Monitoring blood loss Estimation of blood loss is done by weighing blood soaked swabs , sponges (Gravimetric method) and estimation of blood loss in suction bottle (Volumetric method). Most accurate method is colorimetric method . On an average (a rough guide): Fully soaked swab means 20 ml of loss. Fully soaked sponge means 100 to 120 ml of loss. A fist of clots means 200 to 300 ml of loss.

51. 7. Expired Gas Analysis There is multigas analyzer which measures concentration of anaesthetic vapors like nitrous oxide and inhalational agents like halothane, isoflurane etc. These are mass spectrometers and Raman gas analyzers .

52. summary