IntraOperative Monitoring

Intraoperative Monitoring for BSc Nursing.

1. Intraoperative Monitoring By: Azhar Manzoor

2. Introduction Monitoring of patients during surgical procedure.

3. A patient undergoing surgery under anesthesia is usually experiencing a number of disturbances with regard to the normal functioning of several body systems. This means that the patient’s physiological status needs to be monitored at all times Various sensors and electrodes are attached to the patient to gather information. These measurements are displayed on monitors.

4. Routinely measured parameters The parameters measured in most surgical procedures include: The heart’s electrical activity via an electrocardiogram The respiratory rate The blood pressure, which can be measured by both invasive and non-invasive means The body temperature via thermometers, especially when general anesthesia lasts over 30 minutes in duration. The cardiac output

5. The arterial blood oxygen level measured by a pulse oximeter, a photoelectric sensor clipped over the finger or toe. Pulmonary functions such as end-tidal carbon dioxide (ETCO2). Intracranial pressure monitor in patients suffering from trauma to the head, or brain tumors, edema, or intracranial hemorrhage. The sensor is inserted through a burr hole made in the skull.

6. History The most primitive method of monitoring the patient 25 years ago was continuous palpation of the radial pulsations through out the operation.

7. Purpose To maintain the normal patient physiology & homeostasis throughout anesthesia and surgery. Surgery is a very stressful condition tachycardia, arrhythmias. Most drugs used for eneral & regional anesthesia cause cardiogenic shock , myocardial depression, hypotension & arrhythmias. Blood loss → anemia, hypotension. So it is necessary to recognize when the patient is in need of blood transfusion .

8. The FOUR basic monitors. We are not authorized to start a surgery in the absence of any of these monitors: ECG. SpO2: arterial O2 saturation. Blood Pressure: NIBP (non-invasive), IBP (invasive). ± [Capnography]. The most critical 2 times during anesthesia are: INDUCTION - RECOVERY. Exactly like “ flying a plane ” induction (= take off) & recovery (= landing). The aim is to achieve a smooth induction & a smooth recovery & a smooth intraoperative course.

9. (1) ECG Graphical representation of electrical activity of heart. The machine which is used to record the electrical activity of heart is ELECTROCARDIOGRAPH. The graph on which the electrical activity is recorded is called ELECTROCARDIOGRAM.

10. Significance of ECG EC G g i v es info r ma tion abou t rat e an d r h y t h m of the heart. It is a diagnostic tool for various heart conditions like hypertrophies , ischemia, infarction , arrhythmias and pace maker activity. Timing of ECG monitoring: Throughout the surgery: before induction until recovery

11. ECG Paper This is long role of paper ,composed of small squares . One square is 1mm wide and 1 mm high. On ECG paper there are thick lines, between two thick lines there are 5 small squares. The speed of ECG machine is 25 mm per second.

12. The time internal of each small square can be calculated as 25 small sqrs are equal to 1 second. 1 small sqr is equal to 1/25 second. i.e 0.04 seconds.

13. vertically the small square represent the amount of electrical potential. One small sqr represent the potential of 0.1 mv. 10 small squares represent the potential of 1 mv.

14. ECG Leads There are 10 electrodes in 12 lead ECG placed on patients limbs and on the surface of chest.

15. How to attach ECG electrodes: Prepare the skin Before placing your electrodes, it is very important to prepare the subject's skin by wiping the chest area thoroughly with skin cleansing (alcohol) swabs. This removes any oil that may be on the skin and which can cause drift in your ECG/EKG signals. Once the skin is clean, find and mark the placements for the electrodes...

16. Find and mark the placements for the electrodes:

17. Apply limb leads 

18. Wave Forms P wave Atrial depolarization QRS complex Ventricular depolarization T wave Ventricular repolarization

19. P Wave P Wave shows atrial depolarization.. Its duration is 0.1 sec (2 and half small sqr ) and height is 2.5 mv (2 and half small sqr ). Presence of p waves in ECG strip shows the sinus rhythm.

20. QRS Complex QRS complex represent the ventricular depolarization. its normal duration is about 0. 08 seconds ( less than 2 small sqr ) and hight is about 5 to 20 small sqrs . Q wave is first wave of this complex but often absent.

21. Q w a v e presen t the int e r v en t ricula r depolarization. It is first wave in ECG with negative deflection. Q wave greater than 1/3 the height of the R wave, greater than 0.04 sec are abnormal and may represent the old infarction.

22. T Wave it represent the ventricular repolarization. It is repolarizing wave but shows the upward deflection.

23. T wave should not be more than one third of R wave. T wave inversion represent ischemia of heart. Tall and peaked R wave is present in hyperkalemia.

24. (2) SpO2 SpO2, also known as blood oxygen saturation , is a measure of the amount of oxygen-carrying hemoglobin in the blood. The body needs there to be a certain level of oxygen in the blood or it will not function as efficiently. In fact, very low levels of SpO2 can result in very serious symptoms. This condition is known as hypoxemia. There is a visible effect on the skin, known as cyanosis due to the blue (cyan) tint it takes on. Hypoxemia (low levels of oxygen in the blood) can turn into hypoxia (low levels of oxygen in the tissue).

25. Timing of SpO2 monitoring: Throughout t he surgery: It is the LAST monitor to be removed off the pt before the pt is transferred outside the operating room to recovery room. SpO2 monitoring should be continued in recovery room.

26. Measuring SpO2 There are many ways that the blood can be tested to ensure it contains normal oxygen levels. The most common way is to use a pulse oximeter to measure the SpO2 levels in the blood. Pulse oximeters are relatively easy to use, and are common in health care facilities and at home. To use a pulse oximeter, simply place it on your finger. Can also be applied to the ear lobe . A percentage will be displayed on the screen. This percentage should be between 94 percent and 100 percent, which indicates a healthy level of hemoglobin carrying oxygen through the blood. If it is less than 90 percent, you should see a doctor.

27. Cyanosis of the tissue in the hand

28. Fallacies & Inaccuracies occur when: Misplaced on the pts finger, slipped. Pt movement, shivering. T issue perfusion (cold extremities) → warm the pt , put a glove filled with warm water in the pts hand (always avoid hypothermia). Cardiac arrest.

29. Rules Keep the sound of the pulse oximeter ON at all times. ALWAYS Remember that your clinical judgement is much more superior to the monitor. Check pt colour for cyanosis: lips, nails. If hypoxemia occurs immediately check the pts colour : nails & lips, then manage accordingly and call for help.

30. (3) Blood Pressure Timing of BP monitoring : throughout the surgery. Frequency of measurement : By default every 5 minutes. Every 3 minutes: immediately after spinal anesthesia. Every 10 minutes: eg . In awake pts under local anesthesia.

31. Reading errors/Failures Pressure line is disconnected. Leakage from damaged cuff. Line is compressed (under someone’s foot or under a weal). Line contains water from washing!

32. How to Attach Correct cuff size : width of the cuff should be 1.5 times limb diameter and should occupy at least 2/3 of the arm. 2 cuff sizes for adult: blue : for most adult individuals (60-90 Kg), red : for morbid obese. Selection of appropriate cuff size is important because a ti gh t cuff leads to false hi gh readings, while a L oose cuff gives false L ow readings.

33. IBP : It is beat to beat monitoring of ABP via an arterial cannula. Indicated in: major surgeries, cardiac surgery, in surgeries involving extreme hemodynamic changes/instability eg . Pheochromocytoma .

34. (4) Capnography Definition Continuous CO2 measurement displayed as a waveform sampled from the patient’s airway during ventilation. Normal range : 35-40 mmHg What is EtCO2? A point on the capnogram . It is the final measurement at the endpoint of the pts expiration before inspiration begins again. It is usually the highest CO2 measurement during ventilation.

35. Terminology Capnography :- A real time waveform recorded of the concentration of carbon dioxide in the respiratory gases. Capnogram :- it is waveform + numeric value.

36. Phases of the capnogram : A-B End of inspiration B-C Beginning of expiration C-D Alveolar plateau D-E Beginimg of new breath E-A End of inspiration

37. Factors that affect CO2 levels Increase in ETCO2 Decrease in ETCO2 Increased muscular activity Decreased muscular activity Increased cardiac output Decreased cardiac output hypoventilation Hyperventilation Partial airway obstruction Pulmonary embolism

38. Individual system monitering Respiratory System. CNS: Awareness. Temperature. Monitoring after Extubation & Recovery.

39. Respiratory monitoring Clinical monitoring: Colour : cyanosis : nails , lips , palms , conjunctiva. Chest rise & fall ( inflation ). Ventilator sound : during respiratory cycle. Abnormal sounds eg . leakage, disconnection, high airway pressure.

40. CNS Awareness Clinical monitoring: Signs of pt awareness: Movement, grimacing (facial expression) Pupils dilated. Lacrimation. T a c h yc a rd i a . HTN. Sweating : is always an alarming/warning sign. Causes H y p o g l y c e m i a . Hypercapnia . Thyroid storm ( thyrotoxic crisis). Fever.

41. Temperature monitoring Clinical monitoring : ur hands. Monitors : temperature probe: esophageal, nasopharyngeal .

42. Nasopharyngeal

43. Complications of hypothermia Cardiac arrhythmias: VT & cardiac arrest. Myocardial depression. Delayed recovery (delays drug metabolism). Coagulopathy.

44. How to avoid hypothermia : Warm IV fluids. Intermittently switching off air- c o n d i t i o n i n g e s p . t o w a r d s t h e e n d of surgery ( ↑ ambient room temp). Pediatrics: warming blanket.

45. Monitoring after extubation and recovery After extubation : immediately fit the face mask on the pt and observe the breathing bag Good regular breathing with adequate tidal volume transmitted to the bag. No transmission to the bag → respiratory obstruction SpO2: ˃ 92% Breathing : regular. Level of consciousness : fully conscious. 1) obeying orders, 2) eye opening, 3) purposeful movement. Most I MP: P t must b e a b l e t o p r o t e ct h i s o w n airway.

46. To summarize The 4 basic monitors displayed on the screen: ECG. BP. SpO2. ± Capnogram (EtCO2).