Objective Structured Clinical Examination

OSCE for Anaesthesia postgraduates

1. 1. What gas cylinder is this? 2. Where it is used? 3 What’s the PIN Index? 4. What is the Tare weight of “E type” Oxygen cylinder? 5. If weight of the liquid inside the cylinder is 3.4 kg The molecular weight of the gas is 44 Calculate of volume of the gas

2. 1. Aluminium N2O cylinder. 2. Used in MRI 3. Pin Index: 3:5 4. Tare weight of “E type” Oxygen cylinder is 5.4 kg 5. 44 gm(1mol) occupies = 22.4 L 3400 gm occupies = 22.4 x 3400 = 1730 L 44 OSCE 1: ANSWER

3. Ventilator graphic of a COPD patient on Volume A/C MODE. 1.Pick out the abnormality. 2. How will you confirm it? 3. What is Braschi valve? 4. How will you manage it? 5. How to eliminate it? OSCE 2

4. ANSWER: OSCE 2 1. Auto PEEP 2. End-expiratory pause: The exhalation valve is occluded for 1 - 2 sec. (some up to 4 sec) just prior to next inspiration; inspiration is delayed. As Palv equilibrates with the proximal Paw, the level of auto-PEEP is reflected on the pressure gauge during the pause (accuracy is questionable). Auto-PEEP = total PEEP - set PEEP PEEPI = PEEPtot - PEEPE 3. Braschi valve A T-piece adaptor with a one-way valve and cap. The cap is removed during expiration. While the next mechanical breath is diverted out the uncapped hole, the pressure equilibrates between the patient's lungs and circuit. Auto-PEEP pressure is read on a manometer proximal to the patient. 3. Look at the inspiratory/expiratory flow waveform: If the waveform does not return to baseline (still expiring when delivery of breath initiates), there’s probably auto PEEP! 4. Compare the inspiratory vs. expiratory volumes. If the inspiratory volumes are much higher then the expiratory volumes, consider auto PEEP. 4.Management of Auto PEEP To reduce the likelihood of auto-PEEP, the tidal volume or frequency may be reduced. The frequency during pressure support ventilation should be kept less than 20 breaths per minute if possible. 5. Two methods may be useful to reduce or eliminate the auto-PEEP, and they are (1) Improving ventilation and reducing air trapping by bronchodilators and (2) Prolonging the expiratory time by increasing the flow rate or reducing the tidal volume or frequency

5. 1. Which patient is most likely to desaturate? 2. Why? 3. What are the Factors Increasing the Risk of Hypoxemia During One- lung Ventilation? 4. What’s the role of Auto-PEEP in OLV? 5. Preferred method of lung isolation for ages: 2–8 yr ? OSCE 3

6. OSCE 3: ANSWER 1. The patient on the right is more likely to desaturate. 2. There are several factors that are predictive of the risk of hypoxemia developing during OLV. First, the side of lung collapse is important. The mean PaO2 level is 70 mmHg higher in patients undergoing left thoracotomies versus right. Second , counter intuitively, patients with good preoperative spirometric pulmonary function tests tend to have lower PaO2 values during OLV than patients with poor spirometry. This may be related to auto-PEEP in patients with poor spirometry. Other predictive factors include the A-aO2 gradient during two-lung ventilation which correlates inversely with the PaO2 during OLV; that is, the higher the A-aO2 gradient, the lower the PaO2 will be during OLV. Also hypoxemia occurs more frequently during OLV in the supine position6 than in the lateral position. Finally, if the preoperative V/Q scan reveals that a high percentage of the ventilation or perfusion is going to the operative lung, intraoperative hypoxemia is more likely to occur. 3. Summmary : Factors Increasing the Risk of Hypoxemia During One- lung Ventilation: • Right-sided surgery • Good preoperative spirometry (FEV1 or FVC) • Poor PaO2 during two-lung ventilation • Supine (vs. lateral) patient position • High percentage of ventilation or perfusion to the operative lung on preoperative V/Q scan 4. Auto-PEEP is considered detrimental in most ventilated patients. However, in the unusual situation of one-lung ventilation, Auto-PEEP can compensate for the weight of the mediastinum pressing down on the ventilated lung and restore the ventilated lung to its functional residual capacity (FRC), thereby decreasing atelectasis in the ventilated lung. 5. Endobronchial blocker (Preferred method for ages: 2–8 yr (coaxial technique)

7. A 29 year-old male with a history of Type I diabetes mellitus is seen in your office for a routine insurance examination. Laboratory Data shows:: OSCE 4 Chemistry Normal Values  Arterial Blood Gas Urine Sodium  140 136-146 mmol/L pH 7.35 P C02 30mmHg P 02 105mmHg bicarbonate 16mmol/L pH 5.5 Potassium  6.4 3.5-5.3 mmol/L Chloride 112 98-108 mmol/L Total C02  16 23-27 mmol/L BUN  44  7-22 mg/dl Creatinine  2.5 0.7-1.5 mg/dl Glucose  110 70-110 mg/dl What is the primary acid-base abnormality? Calculate his anion gap. Is there a compensatory mechanism for this abnormality? What is the predicted compensatory response? Is this disorder simple or mixed?

8. What is the primary acid-base abnormality? Metabolic acidosis Calculate his anion gap. 140 - (16 + 112) = 12 Is there a compensatory mechanism for this abnormality? Hyperventilation What is the predicted compensatory response? (25 - 16) x 1.2 = 10.8; expected PCo2 = 40mmHg - 10.8 mmHg) = 29.2 mmHg + 2 mmHg Is this disorder simple or mixed? Simple What is the respiratory compensation for chronic metabolic acidosis? How do you assess whether it is appropriate? Metabolic acidosis: Expected PaCO2 decrease: (Normal bicarb-Observed bicarb) x 1.2 Estimation of expected PaCO2 for a given acidic pH also enables us to determine whether respiratory compensation is appropriate. Compensation is never complete. If the pH is normal there is probably a superimposed second acid base disturbance. OSCE 4: ANSWER

9. Which patient is more hypoxemic, and why? Patient A: pH - 7.48, PaCO 2 - 34 mm Hg, PaO 2 - 85 mm Hg, SaO2 - 95%, Hemoglobin - 7 gm% Patient B: pH - 7.32, PaCO2 - 74 mm Hg, PaO2 - 55 mm Hg, SaO2 - 85%, Hemoglobin - 15 gm% Hint: Be specific -- this is not a question you guess at OSCE 5

10. OSCE 5. Which patient is more hypoxemic, and why? Patient A: pH 7.48, PaCO 2 34 mm Hg, PaO 2 85 mm Hg, SaO2 95%, Hemoglobin 7 gm % Patient B: pH 7.32, PaCO2 74 mm Hg, PaO2 55 mm Hg, SaO2 85%, Hemoglobin 15 gm % Hint: Be specific -- this is not a question you guess at. ANSWER: The body needs oxygen molecules, so oxygen content takes precedence over partial pressure in determining degree of hypoxemia. In this problem the amount of oxygen molecules contributed by the dissolved fraction is negligible and will not affect the answer. Also, the PaCO2 and pH are not needed to answer the question. Patient A: Arterial oxygen content = .95 x 7 x 1.34 = 8.9 ml O2/dl Patient B: Arterial oxygen content = .85 x 15 x 1.34 = 17.1 ml O2/dl Patient A, with the higher PaO2 but the lower hemoglobin content, is more hypoxemic.

11. A patient is admitted to the ICU with the following lab values: BLOOD GASES pH: 7.40 PCO2: 38 HCO3: 24 PO2: 72 ELECTROLYTES, BUN & CREATININE Na: 149 K: 3.8 Cl : 100 CO2: 24 BUN: 110 Creatinine : 8.7 What is(are) the acid-base disorder(s)? OSCE 6

12. OSCE 6: ANSWER First, note that pH, PCO2, calculated HCO3 and serum CO2 are all normal (and, in this case, the venous CO2 = arterial HCO3 -). At first glance it appears there is no acid-base disorder, and that the only obvious abnormality is the markedly elevated BUN and creatinine. However, by going through the steps outlined in this section, a different picture emerges. Step 1: Anion gap AG = Na + - ( Cl -+ CO2) = 149 - (100 + 24) = 25 This high an AG indicates an anion gap metabolic acidosis. Step 2: Delta anion gap Calculated AG 25 mEq /L normal AG = 12 mEq /L 25 - 12 = 13 mEq /L; this is the excess or delta anion gap Step 3: Delta serum CO2 = normal CO2 - measured CO2 =27 (average normal venous CO2) - 24 = 3 mEq /L Step 4: Bicarbonate Gap = delta AG - delta CO2 = 13 - 3 = 10 mEq /L (Normal BG is about + or - 6 mEq /L) This means the measured bicarbonate is 10 mEq /L higher than expected from the excess AG, indicating (in this case) a metabolic alkalosis. Thus this patient, with normal pH and PaCO2 , has BOTH metabolic acidosis and metabolic alkalosis. The patient was both uremic (causing metabolic acidosis) and had been vomiting (metabolic alkalosis). The bicarbonate gap: Useful in identifying mixed acid base disorders In single acid base disorder the difference between anion gap and the change in total CO2 should be negligible In other words change in total CO2 (Normal total CO2-observed total CO2) should be equal to anion gap. Excess bicarbonate gap suggests metabolic alkalosis Decrease in the gap suggests metabolic acidosis

13. Given the following set of electrolytes, calculate both the anion gap and the bicarbonate gap, then state the most likely acid-base disorder(s) from this information. Na: 153 K: 4.0 Cl : 100 CO2: 23 a) metabolic acidosis and metabolic alkalosis b) metabolic acidosis alone c) metabolic alkalosis alone d) chronic respiratory alkalosis e) normal acid-base state; need arterial blood gases to determine if there is an acid-base disorder OSCE 7

14. Metabolic acidosis and Metabolic alkalosis Anion gap = Na - ( Cl + CO2) = 153 - (100 + 23) = 30 mEq /L. Since normal anion gap is about 12 (+ or - 4) mEq /L, an AG of 30 indicates a definite anion gap metabolic acidosis. Delta AG = 30-12=18 mEq /L Delta CO2 = 27-23= 4 Bicarbonate Gap = 18-4=14 mEq /L Bicarbonate gap determines if the measured serum CO2 is appropriate for the measured anion gap. The shortcut to the BG gives the following answer: Na - Cl - 39 = 153 - 100 - 39 = 14 mEq /L. Normal BG is about + or - 6 mEq /L. A value of 14 mEq /L indicates a serum CO2 inappropriately elevated for this anion gap, and therefore a concomitant metabolic alkalosis. OSCE 7: ANSWER The bicarbonate gap: Useful in identifying mixed acid base disorders In single acid base disorder the difference between anion gap and the change in total CO2 should be negligible In other words change in total CO2 (Normal total CO2-observed total CO2) should be equal to anion gap. Excess bicarbonate gap suggests metabolic alkalosis Decrease in the gap suggests metabolic acidosis

15. Extremely SHORT and TITRATED analgesic. DON'T give in preoperative holding area! Class: Synthetic narcotic Dose: Recommended for infusion only. -Loading 1 mcg/kg slow bolus -Maintenance 0.25-2 mcg/kg/min - Postop analgesia/sedation 0.05-0.3 mcg/kg/min *Eliminated RAPIDY via ester hydrolysis *Once awake, pts have NO residual pain relief *Asset & Liability - if you want some narcotic on board for after the case for post-op pain relief b/c drug is so short acting. What drug is this? OSCE 8

16. OSCE 8: Answser : Remifentanil

17. IDENTIFY THE CAPNOGRAM WAVE FORM OSCE 9

18. A   , Prolonged phase II, increased α angle, and steeper phase III suggest bronchospasm or airway obstruction. B   , Expiratory valve malfunction resulting in elevation of the baseline, and the angle between the alveolar plateau and the downstroke of inspiration is increased from 90°. This is due to rebreathing of expiratory gases from the expiratory limb during inspiration. C   , Inspiratory valve malfunction resulting in rebreathing of expired gases from inspiratory limb during inspiration (reference 5 for details). D   , Capnogram with normal phase II but with increased slope of phase III. This capnogram is observed in pregnant subjects under general anesthesia (normal physiologic variant ). E   , Curare cleft: Patient is attempting to breathe during partial muscle paralysis. Surgical movements on the chest and abdomen can also result in the curare cleft. F   , Baseline is elevated as a result of carbon dioxide rebreathing . G   , Esophageal intubation resulting in the gastric washout of residual carbon dioxide and subsequent carbon dioxide will be zero. H, Spontaneously breathing carbon dioxide waveforms where phase III is not well delineated. I   , Dual capnogram in one lung transplantation patient. The first peak in phase III is from the transplanted normal lung, whereas the second peak is from the native disease lung. A variation of dual capnogram (steeple sign capnogram – dotted line) is seen if there is a leak around the sidestream sensor port at the monitor. This is because of the dilution of expired PCO 2 with atmospheric air. J   , Malignant hyperpyrexia where carbon dioxide is raising gradually with zero baseline suggesting increased carbon dioxide production with carbon dioxide absorption by the soda lime. K   , Classic ripple effect during the expiratory pause showing cardiogenic oscillations. These occur as a result of to-and-for movement of expired gases at the sensor due to motion of the heartbeat during expiratory pause when respiratory frequency of mechanical ventilation is low. Ripple effect like wave forms also occur when forward flow of fresh gases from a source during expiratory pause intermingles with expiratory gases at the sensor. L   , Sudden raise of baseline and the end-tidal PCO 2 (PETCO 2 ) due to contamination of the sensor with secretions or water vapor. Gradual rise of baseline and PETCO 2 occurs when soda lime is exhausted. M   , Intermittent mechanical ventilation (IMV) breaths in the midst of spontaneously breathing patient. A comparison of the height of spontaneous breaths compared to the mechanical breaths is useful to assess spontaneous ventilation during weaning process. N   , Cardiopulmonary resuscitation: capnogram showing positive waveforms during each compression suggesting effective cardiac compression generating pulmonary blood. O   , Capnogram showing rebreathing during inspiration. This is normal in rebreathing circuits such as Mapleson D or Bain circuit.

19. OSCE 10 1.What is a scalar and what do you mean by loop? 2.How do you identify the patient initiated breath in the ventilator graph? 3.What happens to PIP and Pplat in case of increased resistance? 4.When inspiratory flow takes longer to return to baseline, what does this indicate on a flow waveform? 5.When expiratory flow doesn’t return to baseline, what does this indicate on a flow waveform? 6. An increase in airway resistance causes the pressure-volume loop to do what? 7. What does a break in the loop indicate? 8.What does a shift upward indicate on a pressure-volume loop? 9.What indicates a leak on a flow-volume loop? 10.Which type of inspiratory flow pattern is most commonly used in the clinical setting?

20. OSCE- 10 Answer 1. Scalars-Plots of pressure, flow, or volume against time. Loops-Plots of pressure, flow, or time against each other. Time is not graphed. 2. A pressure deflection below baseline right before a rise in pressure. 3. The PIP will increase while the Pplat stays the same. 4. Airway obstruction. 5. Air trapping 6. It causes it to widen. 7. That a leak is present. 8. Increased compliance. 9. The expiratory part of the loop does not return to the starting point. 10. Square and decelerating

21. OSCE 11 1. Name 2 sites of invasive blood pressure monitoring? 2. What does Allans test confirm ? 3. What are the other uses of arterial cannulation ? 4. What are the two procedures you will do while setting up a transducer? 5. Dicrotic notch represents what event in cardiac cycle? 6. How will you identify under damped waveform? 7. State 2 differences between central and peripheral waveforms . 8. How is the Mean arterial pressure calculated from the waveform?

22. Name 2 sites of invasive blood pressure monitoring? RADIAL , FEMORAL 2 . What does Allans test confirm ? ULNAR COLLATERAL FLOW 3 . What are the other uses of arterial cannulation ? BLOOD GAS ESTIMATION , IABP insertion 4 .What are the two procedures you will do while setting up a transducer? Zeroing , leveling 5. Dicrotic notch represents what event in cardiac cycle? Closure of aortic valve 6.How will you identify under damped waveform? Excessive peaks in waveform 7. State 2 differences between central and peripheral waveforms PROMINENT SYSTOLIC, DIASTOLIC PEAKS , LATE DICROTIC NOTCH 8 .How is the Mean arterial pressure calculated from the waveform? AREA UNDER CURVE OF WAVEFORM OSCE 11: ANSWER

23. OSCE 12: 1. What test is predicted here? 2. It is done to test which component of Boyles apparatus? 3. Can we test each valve separately? 4.What are the other test available to test this system? 5. Can we use Universal Leak Test to test this system?

24. OSCE 12: ANSWER To test patency of Inspiratory and Expiratory valves and APL valve in circle system 2 1

25. OSCE 12: ANSWER 4. Positive pressure test can be used to test circle system up to CGO. 5. NO 3

26. OSCE 13: True or False: The PO2 in a cup of water open to the atmosphere is always higher than the arterial PO2 in a healthy person (breathing room air) who is holding the cup.

27. OSCE 13: ANSWER The PO2 in the cup of water is always higher. This is for several reasons. First, there is no barrier to oxygen diffusing into the water; thus the PO2 in the cup will be the same as the atmosphere, at sea level approximately 160 mm Hg. Second, there is no CO2 coming from the cup to dilute the oxygen, as there is in people. Third, there is no V-Q inequality or shunt; even healthy people have a difference between alveolar PO2 and arterial PO2 for this reason. Thus a healthy person and a cup of water exposed to the atmosphere at sea level would have PO2 values of about 100 mm Hg and 160 mm Hg, respectively.

28. OSCE 14: ECG A 39-year-old female patient presented to the emergency department with chest pain of 6 hours duration. This is the ECG recorded at the time of admission. 1. Heart rate in this ECG is about 75 beats per minute. TRUE/FALSE 2. This ECG is suggestive of an inferior infarction. TRUE/FALSE 3. A blood test on admission is likely to show elevated troponin-T levels. TRUE/FALSE 4. Aspirin should be given orally as soon as possible. TRUE/FALSE 5. An angiogram would show occlusion of the left anterior descending (LAD) artery. T/F

29. OSCE: 14 ECG ANSWER 1 . False . The heart rate in this ECG is about 120 per minute. The ECG is recorded at a speed of 25mm per second; one large square on the ECG recording paper represents 0.20 sec and 300 large squares represent one minute. In the given ECG there are 2.5 large squares between two consecutive R waves. Since the rhythm is regular, the rate is calculated as 300/2.5 =120. 2. False. There is ST segment elevation in V1-V4, lead I and Avl suggesting an anterolateral infarction. 3. True. Although troponin-T peaks after 12 hours of myocardial infarction, it is detectable in serum about 3-6 hours after an acute myocardial infarction. Its level remains elevated for 14 days. Creatine kinase-MB (CK-MB) levels begin to rise within 4 hours after injury, peak at 18-24 hours, and return to normal over 3-4 days. 4. True . Aspirin in a dose of 150-300mg should be administered on diagnosing acute MI. Aspirin interferes with function of the enzyme cyclo-oxygenase and inhibits the formation of thromboxane A2. Aspirin prevents additional platelet activation, and interferes with platelet adhesion and cohesion. 5. True . The circumflex artery branch of the left coronary artery (LCA) and diagonal branches of the LAD are involved in an anterolateral infarct.

30. What is this equipment? Name the various components of this system. What is the fresh gas flow (FGF) required during spontaneous ventilation? 4. What is the FGF required during controlled ventilation? 5. What are the advantages of this system? OSCE 15

31. Humphrey ADE system: The Humphrey ADE system can be converted into a Mapleson A to D or E by selecting the lever position. For spontaneous ventilation it is used as a Mapleson A and for controlled ventilation it is used as a Mapleson E system. - Inspiratory and expiratory tubing. - Humphrey block which consists of an APL valve with indicator and a reservoir bag. Lever to select a spontaneous or controlled mode. - Ventilator connection port and safety pressure relief valve. 50-60ml/Kg/min. 70ml/Kg/min. - It is an efficient system both for spontaneous and controlled ventilation. - A single system for adult and children. - Choice of technique: as a semi-closed system without the soda lime canister or, as a circle system with the canister. OSCE 15: ANSWER

32. A 70-year-old male patient is scheduled for repair of a left inguinal hernia. There is a history of angina and syncope on exertion. 1. The heart rate in this ECG is approximately 75 beats per minute. TRUE/FALSE 2. This ECG shows a first degree heart block. TRUE/FALSE 3. This could be due to fibrosis of the bundle of His. TRUE/FALSE 4. This could be due to block in the left anterior descending (left inter-ventricular artery) branch of the LCA. TRUE/FALSE 5 This patient may need cardiac pacing prior to surgery. T/F OSCE16

33. False. Ventricular rate is about 40/minute. False. Complete heart block. True. True. True. KEY POINTS In complete heart block, the P wave and QRS complex are independent of each other. A normal axis is between +90 to -30°. Left anterior hemi-block is suspected in the presence of left axis deviation. The left bundle branch usually receives blood from the left anterior descending artery. OSCE 16 ANSWER

34. A 57-year-old man is admitted for laparoscopic cholecystectomy. He has a history of COPD and shortness of breath on minimal exertion. Routine pre-operative blood tests reveal the following results. 1. Hb: 16.9g/dl, WCC: 11.8 x 109 cells/L, platelets: 479 x 109 cells/L, Hct : 0.54. 2. Na+: 136mmol/L, K+: 3.1mmol/L, urea: 8.7mmol/L, creatinine: 98 μ mol/L. 3. ABG in room air - pH: 7.33, PaO2: 58 mm of Hg, PaCO2: 55 mm of Hg, HCO3: 34mmol/L. 4. FEV1: 1.1L, FVC: 2.9L. 1.Name five abnormalities shown in the test results 2. What is the likely cause of this patient’s shortness of breath? 3. Name four physical signs you may find on examining this patient. 4. Name two changes you might expect to see on the chest X-ray 5. What two ECG changes might you expect to find in this patient? OSCE 17

35. Q1. Name five abnormalities shown in the test results. Polycythaemia , hypokalaemia , hypoxia, hypercarbia, compensated respiratory acidosis, obstructive lung disease or airflow limitation. 2. What is the likely cause of this patient’s shortness of breath? Chronic obstructive airway disease, Type 2 respiratory failure or cor pulmonale. 3. Name four physical signs you may find on examining this patient. Central cyanosis, clubbing, tremor, bounding pulse, tachypnoea, raised JVP, hyper-resonant percussion note, displaced apex, difficult to palpate apex, peripheral oedema , hepatomegaly, widespread wheeze, fine and/or coarse crackles. 4. Name two changes you might expect to see on the chest X-ray. Hyperinflation, flat diaphragm, enlarged hilar vessels, loss of peripheral vascular markings, emphysematous bullae and enlarged heart 5. What two ECG changes might you expect to find in this patient? Peaked P waves, right axis deviation, right ventricular hypertrophy (RVH), right bundle branch block (RBBB), atrial fibrillation (AF). OSCE 17: ANSWER

36. An elderly patient with a history of breathlessness in the past, now presenting for elective surgery. 1. The rhythm is sinus. TRUE/FALSE 2. The rate is 100 beats/minute. TRUE/FALSE 3. The PR interval is within the normal range. TRUE/FALSE 4. There is a left bundle branch block. TRUE/FALSE 5. The rhythm is suggestive of atrial pacing. TRUE/FALSE OSCE 18

37. The rhythm is sinus. False. Pacemaker rhythm. The rate is 100 beats/minute. False. 75/minute. The PR interval is within the normal rang e. False. The P wave is not seen and the pacemaker spike is followed by a QRS complex. There is a left bundle branch block. True. It is commonly present with a pacing rhythm. The rhythm is suggestive of atrial pacing. False. There are no P waves; it is suggestive of ventricular pacing. OSCE 18: ANSWER

38. A 75 year old lady(weight 52kg) receiving an oral hypoglycaemic drug and diet to control her diabetes is admitted following 24 hours of nausea & vomiting with abdominal pain suggestive of appendicitis. Lab.values for that patient: 1.The patient has combined metabolic and respiratory acidosis. True/False 2. How to calculate the normal anion gap? Write the formula. Calculate the anion gap in this case 3. How to calculate the dose of insulin needed here? 4.The diagnosis is non- ketotic hyperosmolar acidosis. True/False 5.A urine osmolarity of more than 500 mosmol /kg is found in pre-renal failure. True/False 98 mm Hg 18 mm Hg 540 mg% 270 mg% OSCE 19

39. 1.The patient has combined metabolic and respiratory acidosis. False 2. How to calculate the normal anion gap? Write the formula. Calculate the anion gap in this case. ( Na + K ) – ( Cl + HCO3) = 29meq/L 3. How to calculate the dose of insulin needed here? Blood sugar /150 = 540/150=3.6 units / hour 4.The diagnosis is non- ketotic hyperosmolar acidosis. False: (Non- ketotic Hyperosmolar status-Low anion gap with higher osmolarity of over 360mosmoles/L) 5.A urine osmolarity of more than 500 mosmol /kg is found in pre-renal failure. True OSCE 19: ANSWER

40. A 140 kg obese patient is posted for bariatric surgery-sleeve resection of stomach 1. How is BMI calculated? 2. Write the Broca's index to calculate the ideal body weight for males. 3. Tidal volume in morbid obesity: Increased/Decreased/ Nochange 4. What will happen to cardiac output in morbid obese patients? 5. Rapid sequence induction is an good option for this patient. True/false 6. Best way of identifying the correct endotracheal tube placement? 7. PCA is a good option for postoperative analgesia. True/false 8. For IPPV, calculation of TV to be based on lean body weight. True/false 9. A small BP cuff underestimates the BP reading. True/False 10. Titrated intravenous narcotics are better than intra muscular narcotics for post operative pain relief. True/false OSCE 20

41. How is BMI calculated? BMI=weight in kg/Height in m2 2. Write the Broca's index to calculate the ideal body weight for males. Broca's index: IBW in Males = Height in cm- 100. Females = Height in cm- 105 3. Tidal volume in morbid obesity: Increased 4. What will happen to cardiac output in morbid obese patients? Increased 5. Rapid sequence induction is an good option for this patient. False 6. Best way of identifying the correct endotracheal tube placement? Capnogram 7. PCA is a good option for postoperative analgesia. True 8. For IPPV, calculation of TV to be based on lean body weight. True 9. A small BP cuff underestimates the BP reading. False 10. Titrated intravenous narcotics are better than intra muscular narcotics for post operative pain relief. True OSCE 20: ANSWER

42. You are in the labour ward when a woman self presents at 37 weeks, bleeding heavily with known placenta praevia . Regarding massive haemorrhage and transfusion: Massive transfusion is defined as the replacement of the patient’s total blood volume in less than 24 hours. TRUE/FALSE Full blood count and clotting should not be taken until resuscitation with blood products has begun. TRUE/FALSE A platelet count of >75,000/ml should be targeted. TRUE/FALSE This patient should be taken immediately to theatre for caesarean section. TRUE/FALSE Cell salvage should not be used because of risk of amniotic fluid embolism. TRUE/FALSE OSCE 21

43. TRUE: There are a number of definitions for massive transfusion, including statement A. FALSE: Baseline FBC/clotting profiles should be taken with repeat samples and sent regularly to the blood bank to help guide transfusion requirements. TRUE: AAGBI guidance recommends targeting a platelet count of >75,000/ml. FALSE: This woman needs urgent delivery, but resuscitation should be started before induction, as this may precipitate hypovolaemic cardiac arrest with loss of sympathetic tone. FALSE: Cell salvage is not contraindicated in obstetric cases and is endorsed by NICE guidance. Leucocyte depletion filters should be used, with a separated suction system for liquor. OSCE 21 ANSWER

44. Identify the circuit & in which class of Mapleson classification it fits in? Its otherwise called as a controlled rebreathing circuit. True/False What is the fresh gas flow during controlled ventilation to prevent Rebreathing. (in ml/kg/min)? This is more efficient in retaining the moisture in the expired gas. True/False Rebreathing can happen if there is aleak in outer tube. True/False Increasing the length of the breathing tube will not affect the functional analysis. True/False During controlled ventilation with a fresh gas flow 70ml/kg/min, increasing the respiratory rate will proportionally decrease alveolar CO2 tension. True/False The APL valve has a maximum opening pressure of approximately 60 cm of H2O. True/False Venturi principle can be used to check the integrity of this circuit. True/False Increasing the length of the tube doesn’t affect the functional analysis of this circuit. True/False OSCE 22

45. Identify the circuit & in which class of Mapleson classification it fits in? Bain-Mapleson-D Its otherwise called as a controlled rebreathing circuit. True What is the fresh gas flow during controlled ventilation to prevent Rebreathing. (in ml/kg/min)? 100-150 ml/kg/min This is more efficient in retaining the moisture in the expired gas. False - Its a type of T piece Rebreathing can happen if there is aleak in outer tube. False Increasing the length of the breathing tube will not affect the functional analysis. True During controlled ventilation with a fresh gas flow 70ml/kg/min, increasing the respiratory rate will proportionally decrease alveolar CO2 tension. False The APL valve has a maximum opening pressure of approximately 60 cm of H2O. True Venturi principle can be used to check the integrity of this circuit. True Increasing the length of the tube doesn’t affect the functional analysis of this circuit. True OSCE 22: ANSWER

46. Regarding Midazolam The amnestic effects of midazolam are more potent than its sedative effects . TRUE/FALSE What is the effect-site equilibration time for Midazolam? Midazolam exhibits significant lipid solubility, following injection, because the previously open imidazole ring closes at physiological pH (7.4). TRUE/FALSE The principal metabolite of midazolam, 1-hydroxymidazolam is an active metabolite. TRUE/FALSE For reversal of benzodiazepine a single dose of Flumazenil is enough. TRUE/FALSE OSCE 23

47. The amnestic effects of midazolam are more potent than its sedative effects. TRUE (patients may be awake but remain amnestic for events and conversations such as postoperative instructions for several hours) What is the effect-site equilibration time for Midazolam? (0.9 to 5.6 minutes) Despite this prompt passage into the brain, midazolam is considered to have a slow effect-site equilibration time compared with other drugs such as propofol and thiopental. In this regard, IV doses of midazolam should be sufficiently spaced to permit the peak clinical effect to be appreciated before a repeat dose is considered. Midazolam exhibits significant lipid solubility, following injection, because the previously open imidazole ring closes at physiological pH (7.4). TRUE Midazolam has an imidazole ring that allows the drug to be water soluble in an acid pH (pH 3.5). When injected into the bloodstream, midazolam is exposed to the higher physiologic pH and the ring changes shape and the drug becomes lipid soluble. The lipid-soluble form readily crosses the blood-brain barrier to exert its pharmacologic effects. None of the other drugs change form with different pH The principal metabolite of midazolam, 1-hydroxymidazolam is an active metabolite. FALSE. Have no active metabolites. For reversal of benzodiazepine a single dose of Flumazenil is enough. FALSE Flumazenil's half-life is shorter than those exhibited by benzodiazepines. either repetitive flumazenil dosing or continues infusion (0.5-1 ug/kg/min.) may be required OSCE 23: ANSWER

48. Name the LMA. It has a pilot balloon and tube TRUE/FALSE Cuff Pressure fluctuates between inspiration and expiration TRUE/FALSE Head and neck extension is needed, so not ideal for cervical injury patients. TRUE/FALSE How many sizes are available? OSCE 24

49. Name the LMA. The Baska Mask® LMA It has a pilot balloon and tube FALSE It has a non-inflatable self recoiling thin membranous cuff balloon Cuff Pressure fluctuates between inspiration and expiration TRUE Pressure limited to maximum inspiratory pressure during IPPV; fluctuates with ventilatory cycle. Head and neck extension is needed, so not ideal for cervical spine injury patients. FALSE Insertion in neutral position so ideal for cervical spine injury patients How many sizes are available? OSCE 24: ANSWER

50. Name the equipment in Figure. How would you grade the laryngoscopic view? What maneuvers are useful in improving the laryngoscopic view? What signs would indicate that the bougie is in the trachea rather than in the oesophagus ? What should you do if the bougie is in the correct place, but the tube is caught at the laryngeal inlet? OSCE 25

51. Name the equipment in Figure. - Gum elastic bougie (Eschmann tracheal tube introducer). - Magill’s forceps. - Intubating stylet. How would you grade the laryngoscopic view? Cormack and Lehane’s classification of laryngoscopic view: Grade 1: most of the glottis is seen. Grade 2: only the posterior part of the glottis is seen. Grade 3: only the epiglottis is visible. Grade 4: even the epiglottis is not visible. What maneuvers are useful in improving the laryngoscopic view? - Optimum sniffing position. - BURP: backward, upward, right-ward pressure on the thyroid cartilage. - In rapid sequence induction, excessive force applied during cricoid pressure may worsen the laryngoscopic view; a transient release of cricoid pressure may improve the laryngoscopic view. What signs would indicate that the bougie is in the trachea rather than in the oesophagus ? When the angled tip of the bougie slides down the trachea, the tracheal rings can be felt as clicks. What should you do if the bougie is in the correct place, but the tube is caught at the laryngeal inlet? A 90° anticlockwise rotation of the tube facilitates passage of the tube into the trachea OSCE 25: ANWSER

52. How much local anesthetic should be administered per spinal segment to patients between 20 and 40 years of age receiving a lumbar epidural anesthetic? Define epidural test dose. An analgesic effect similar to the epidural administration of 10 mg of morphine could be achieved by which dose of intrathecal morphine? Which local anesthetic undergoes the LEAST hepatic clearance. The “snap” felt just before entering the epidural space represents passage through which ligament? OSCE 26

53. 1-2 mL of local anesthetic will anesthetize about one spinal segment in the 20 to 40-year-old Patient. As one gets older, the dose of local anesthetic mL/segment decreases (e.g., 80 year old may need 0.75-1.5 mL/segment). Also, pregnant patients are more sensitive to local anesthetics and reduced doses are needed. Lidocaine 1.5% with epinephrine 5µg/ml (1:2,00,000) = 3 ml. Intravascular: Increase in HR 20/ mt within one minute. Intrathecal : Motor blockade at 3-5 mts (Weakness in hip flexion) 1 mg. The ratio of epidural to intrathecal dose of morphine is approximately 10:1. Morphine is typically given in doses of 3 to 10 mg in the lumbar epidural space. Intrathecal morphine dosage is 0.2 to 1.0 mg Chlorprocaine . The esters group undergo plasma clearance by cholinesterases and have relatively short half-lives, whereas the amides undergo hepatic clearance and have longer half-lives The ligamentum flavum is tough and dense and a change in the resistance to advancing the needle is often perceived and to many feels like a “snap.” OSCE 26: ANSWER

54. 1. Simplified Acute Physiology Score(SAPS) is a first day scoring system. True/False 2. The orientation to the time and place is given the maximum score In Glascow coma scale. True/False 3. APACHE-II uses 17 physiological variables to a possible score of 0 to 299. True/False 4. SAPS score uses 12 physiological variables for the assessment. True/False 5. Sequential Organ Failure Assessment Score mainly assesses the 4 Important organ functions ( cardiac,renal,liver and CNS) True/False 6. qSOFA score helps to estimate the risk of morbidity and mortality due to sepsis. True/False 7. Unlike other ICU scoring system,SOFA score records the WORST score daily. True/False 8. PaO2 / FIO2 forms one of the variable in MODS score. True/False 9.Aldrete’s scoring system is used for the assessing the discharge fitness From ICU. True/False 10.Able to move all four limbs voluntarily or on command is Given 2 points in Aldrete’s score. True/False OSCE 27

55. 1. Simplified Acute Physiology Score(SAPS) is a first day scoring system. True 2. The orientation to the time and place is given the maximum score In Glascow coma scale. False 3. APACHE-II uses 17 physiological variables to a possible score of 0 to 299. False 4. SAPS score uses 12 physiological variables for the assessment. True 5. Sequential Organ Failure Assessment Score mainly assesses the 4 Important organ functions ( cardiac,renal,liver and CNS) False 6. qSOFA score helps to estimate the risk of morbidity and mortality due to sepsis. False 7. Unlike other ICU scoring system,SOFA score records the WORST score daily. False 8. PaO2 / FIO2 forms one of the variable in MODS score. True 9.Aldrete’s scoring system is used for the assessing the discharge fitness From ICU. False 10.Able to move all four limbs voluntarily or on command is Given 2 points in Aldrete’s score. True OSCE 27: ANSWER

56. What is the effect of the following on SpO2 readings? Methylene blue IV Blue, black, and green nail polish Ambient light, especially fluorescent light Vasoconstriction or hypotension COHb MetHb Pulsatile veins 8 What is the difference between the SpO2 measured by pulse oximetry and the SaO2 measured by the laboratory co-oximeter? 9. Pulse Oximeter is based on which Law? 10. How many wavelengths of light are required to distinguish HbO2 from reduced Hb? OSCE 28

57. 8. SpO2 uses two wavelengths and measures the “functional” saturation, which is given by the following equation: Laboratory co-oximeters use multiple wavelengths and measure the “fractional” saturation, which is given by the following equation: 9. Beer–Lambert law states that at a constant light intensity and hemoglobin (Hb) concentration, intensity of light transmitted through tissues is a logarithmic function of oxygen saturation of Hb. 10. Two different wavelengths, in the red (600–700 nm) and near-IR (800–940 nm) spectrum. 660/940 nm Methylene blue IV: - severe decrease in SpO2 Blue, black, and green nail polish: - absorbance near 660 nm may cause an artifactual decrease in SpO2 Ambient light, especially fluorescent light: - falsely elevate SpO2 reading Vasoconstriction or hypotension: - loss of SpO2 signal COHb : - interpreted as HbO2 and the SpO2 is artifactually raised toward 100% MetHb : - causes the SpO2 to trend toward 85%. Fetal and sickle Hbs have little effect Pulsatile veins: (i.e., tricuspid regurgitation) - cannot be distinguished from pulsatile arteries and can cause falsely low SpO2 readings OSCE 28:ANSWER

58. 1. What type of pacemaker is this ? 2. Enlist 3 indications for Permanent Pacing? 3. What does Position i,ii,iii in pacemaker coding Indicate ? 4. Mention 2 uses of Pacemaker Magnet ? 5. What are the precautions you will take for a patient with a pacemaker in perioperative period. OSCE 29

59. What type of pacemaker is this ? PERMANENT PACEMAKER 2. Enlist 3 indications for Permanent Pacing? COMPLETE HEART BLOCK SICK SINUS SYNDROME RECURRENT TACHYARRHYTHMIA STOKE ADAM ATTACKS 3. What does Position I,ii,iii in pacemaker coding Indicate ? CHAMBER PACED CHAMBER SENSED RESPONSE OF PACEMAKER 4. Mention 2 uses of Pacemaker Magnet ? ABOLISH PACING RESPONSE CHANGE TO ASYNCHRONOUS MODE INTEROGATION OF PACEMAKER 5. What are the precautions you will take for a patient with a pacemaker in perioperative period CHANGE TO ASYNCHRONOUS MODE / USE MAGNET USE BIPOLAR DIATHERMY IF NEEDED ECG MONITORING AND HANDS ON PULSE OSCE 29: ANSWER

60. 1. Name the Bronchial Blockers: A B C D 2. What are the advantages of endobronchial blockers? 3. What size of DLT is indicated for a male with 1.5 m height? 4. Name this tube. Where it is used? 5. Name this tube. Where it is used? OSCE 30

61. 1. Name the Bronchial Blockers: OSCE 30:ANSWER 2. Advantages of endobronchial blockers: Can be used in patients too small for double-lumen tubes, such as children Can be used in an emergency in a patient with an existing ETT Can be used for selective blockade of a specific lobe Safer for patients with a difficult airway No need to change to a different ETT if using postoperative mechanical ventilation 3. Male: 37 Fr if < 1.6 m 5. NARUKE DLT: Used in Tracheostomy patient 4. MARRARO'S BILUMEN PAEDIATRIC DLT (age 8-18 yrs )

62. What is the difference between the therapeutic effect of cardioversion and defibrillation to terminate tachycardias? List two important factors that affect the success of defibrillation. What factors affect transthoracic impedance? What is the optimal energy for open-chest defibrillation? Successful cardioversion of atrial flutter may occur at what energy level? OSCE 31

63. Cardioversion (synchronized DC shock on the R-wave peak of the QRS complex of a stable tachycardia) terminates repetitive reentry loops, whereas defibrillation (unsynchronized shock in the very unstable patient in ventricular fibrillation [VF] and pulseless VT) depolarizes the entire myocardium. Delivery of a shock during cardiac repolarization (T wave) may precipitate VF. 1. Energy output of the defibrillator 2. Resistance to current flow during shock delivery 1. Paddle size – resistance decreases with increasing electrode size (common paddle size 8–10 cm in diameter). 2. Use of gel or paste reduces impedance. 3. Transthoracic impedance decreases with successive shocks. 4. Impedance is slightly higher during inspiration than during exhalation (air is a poor conductor). 5. Firm pressure of at least 11 kg reduces resistance by improving paddle–skin contact. During cardiac surgery, internal paddles applied directly to the heart are used for direct defibrillation of the heart. Low energy levels, 5–25 J, are required since skin impedance is bypassed. 50 to 100 J. OSCE 31: ANSWER

64. Identify the problems in Figure 1 with regard to positioning of the patient What nerves are likely to be damaged in this position? What precautions would you take to avoid nerve damage? Fig 1 Fig 2 What nerves are likely to be damaged in the position shown in Figure 2? What is Seddon’s classification of Nerve Injury? OSCE 32

65. The arm is hyper abducted. The neck is rotated to the other side. Both these factors related to positioning can cause traction on the brachial plexus. Rotation of the neck results in stretch of roots of the brachial plexus, particularly the upper nerve roots. This causes sensory loss over the outer aspect of the arm. The ulnar nerve can be damaged at the elbow, behind the medial epicondyle (cubital groove). Head should be maintained in the neutral position. Arms should not be abducted >90°. Arms should be level with the shoulder. Elbows should be well padded. Forearm should be semi-pronated. This patient is in the prone position. The nerves that are likely to be damaged are: Supra-orbital nerve. Infra-orbital nerve. Ulnar nerve at the elbow. Femoral nerve in the inguinal region. 5. Seddon’s classification is a scheme for describing nerve injury: Neurapraxia: pressure on the affected nerve with no loss of continuity. Axonotmesis : neural tube intact, but the axons are disrupted. These nerves are likely to recover. Neurotmesis: the neural tube is severed. These injuries are likely to be permanent without repair and will likely only achieve partial recovery at best. OSCE 32: ANSWER

66. Can you identify this? What is the normal pulmonary capillary wedge pressure? Where will the proximal lumen open? How far is it from the tip and what does it measure? What is the volume of the balloon in the tip? State at least two uses of this catheter OSCE 33

67. Can you identify this? Pulmonary artery flotation catheter What is the normal pulmonary capillary wedge pressure? 4-12 mmHg. Where will the proximal lumen open? How far is it from the tip and what does it measure? Into the right atrium; 25cm from the tip; it measures CVP. What is the volume of the balloon in the tip? Approximately 1.5ml. State at least two uses of this catheter. - Assessment of volume status where the CVP is unreliable. - Sampling of mixed venous blood to calculate shunt fraction. - Measurement of cardiac output using thermodilution. - Derivation of other cardiovascular indices, such as the pulmonary vascular resistance (PVR), oxygen delivery and uptake. OSCE 33: ANSWER

68. Which nerve block is needed to repair this injury? Which nerve provides sensory innervation to the lateral forearm? Which cord(s) of the brachial plexus is responsible for sensory innervation of the skin over the extensor surface of the forearm to the wrist? Which portion of the upper extremity is NOT innervated by the brachial plexus? Which section of the brachial plexus is blocked with a supraclavicular block? Which nerve is likely to be spared in supraclavicular block? OSCE 34

69. Median and radial nerve blocks were used as anesthesia method for partial index finger amputation. The lateral cutaneous nerve of the forearm The radial nerve (arising from the posterior cord) is responsible for sensory innervation of the skin over the extensor surface of the forearm to the wrist. The arm receives sensory innervation from the brachial plexus except for the shoulder, which is innervated by the supraclavicular nerves from the cervical plexus, and the posterior medial aspect of the arm, which is supplied by the intercostobrachial nerve. The supraclavicular block is at the level of the trunks/divisions. Ulnar N sparing OSCE 34: ANSWER

70. What’s the diagnosis? This condition can be induced by which drugs? If a prolonged QT interval is present wht drug is used to threat the condition? What is the more definitive treatment? If the patient is hemodynamically unstable, what is the treatment? OSCE 35

71. The figure shows torsades de pointes. This condition can be induced by drugs (e.g., quinidine, procainamide, and phenothiazines such as droperidol ), electrolyte abnormalities (e.g., hypokalemia, hypomagnesemia) as well as acute cardiac ischemia or infarction. If a prolonged QT interval is present, the shortening of the QT interval is performed with isoproterenol. Magnesium sulfate has also been used and is recommended by many as the first line emergency drug. If the patient becomes hemodynamically unstable, unsynchronized shocks (defibrillation doses) should be delivered. OSCE 35: ANSWER

72. 1. Name the four nerves that innervate the anterior abdominal wall. 2. What is lumbar triangle of Petit? 3. Fascial planes are ____ echoic in an ultrasound. 4. How will you identify the peritoneal layer in the ultrasound? 5. What are the root values of ilio-inguinal and ilio-hypogastric nerves? 6. What are the nerves blocked by the Inguinal field block? 7. When is a subcostal TAP indicated? 8. Bilateral TAP block can be given for a day care tubectomy. True/False 9. If an extra amount of local anaesthetic solution is used, obturator nerve can be blocked by TAP block- True/False 10. Accidental intravascular injection in to the Inferior epigastric artery is a common complication of TAP block. True/False OSCE 36

73. 1. Name the four nerves that innervate the anterior abdominal wall ? ILIOHYPOGASTRIC , ILIOINGUINAL , SUBCOSTAL BRANCH OF INTERCOSTAL & GENITOFEMORAL 2 . What is lumbar triangle of Petit – ILIAC CREST , EXTERNAL OBLIQUE , LATTISMUS DORSI 3 . Fascial planes are HYPERECHOIC echoic in an ultrasound 4. How will you identify the peritoneal layer in the ultrasound ? SLIDING WITH RESPIRATION 5. LI & L2 6 . Ilio-inguinal, Ilio-hypogastric, Genital branch of genito -femoral 7 .When is a subcostal TAP indicated ? CHOLECYSTECTOMY 8. False 9. False 10. False OSCE 36: ANSWER

74. IDENTIFY THE PERSONALLITY AND THEIR INVENTION 1 2 3 4 5 OSCE 37

75. IDENTIFY THE PERSONALLITY AND THEIR INVENTION Horace Wells – N2O W.T.G. Morton -Ether James Young Simpson - Chloroform August Bier – Spinal John Lundy - Thiopentone OSCE 37: ANSWER

76. What is the diagnostic criteria for RDS? What is the OXYGENATION GOAL in ARDS? What is the PLATEAU PRESSURE GOAL? What is the pH GOAL? What is Berlin new criteria for ARDS? OSCE 38

77. Acute onse t 1.PaO2/FiO2≤ 300 (corrected for altitude) 2.Bilateral (patchy, diffuse, or homogeneous) infiltrates consistent with pulmonary edema 3.No clinical evidence of left atrial hypertension OXYGENATION GOAL: PaO2 55-80 mmHg or SpO2 88-95% PLATEAU PRESSURE GOAL: ≤ 30 cm H2O . pH GOAL: 7.30-7.45 Acidosis Management: The Berlin criteria declared new classification of ARDS; PaO2/FiO2 ratio ≤300 and >200 is mild ARDS; PaO2/FiO2 ratio100-200 is moderate ARDS; PaO2/FiO2 ratio <100 is severe ARDS. In this new criteria, the minimum level of PEEP required for diagnosing ARDS is 5cmH2O. This value excludes hypoxemia caused by atelectasis. OSCE 38: ANSWER

78. Identify this equipment What is the use of a Bourdon gauge? Can this be used for measuring blood pressure? What pressure does this measure - gauge or absolute? What pressure does a mercury barometer measure? What is the difference between absolute and gauge pressure? What is the principle of measuring pressure in a Bourdon gauge? What units are used to measure cylinder pressure? What is the pressure in a full oxygen cylinder? What factors affect the pressure in an oxygen cylinder? OSCE 39

79. This is a Bourdon gauge It is used for measuring the pressure in a cylinder. No, a Bourdon gauge has low precision; therefore it can be used only for measuring high pressures, i.e. above 1 bar. It measures gauge pressure . It measures absolute pressure . Gauge pressure is the measured pressure above the atmospheric pressure, whereas absolute pressure includes atmospheric pressure. Absolute pressure = gauge pressure + atmospheric pressure; at sea level, atmospheric pressure is 1 bar (100 kPa). It consists of a coiled tube, one end of the tube is connected to the source of pressure, whereas the other end is closed and attached to a needle pointer which moves across the dial. When pressure is applied, the tube expands and the curvature is partly straightened out, moving the needle across the dial. Bar, kilo Pascal (kPa), pounds per square inch (PSI). 2000 psi Pressure in the cylinder depends on the mass or weight of gas, ambient temperature and critical temperature. OSCE 39: ANSWER

80. Identify this nerve. It’s a branch of which card of BP? What is the cutaneous innervation of this nerve? What action of the arm will be lost by blocking this nerve? This nerve is spared in which approach of BP block? OSCE 40

81. Musculocutaneous nerve A branch of the lateral cord of the brachial plexus The nerve gives rise to the lateral cutaneous nerve of the forearm. Flexion at elbow will be lost. Axillar approach. PINCH/PINCH PUSH PULL Musculocutaneous N Radial N OSCE 40: ANSWER