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47 Cards in this Set
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ANZCA July 2007 Q118 |
ANSWER A
The blood supply to the spinal cord and the kidney is reduced by 84-90% after cross-clamping the descending thoracic aorta at the level of the left subclavian artery. Elective thoracic aortic repair has a 0.4% incidence of permanent cord injury, but emergency repair of an aortic rupture has a 24-40% incidence. The incidence of perioperative spinal cord injury is increased by: * cross-clamp times of greater than 30 mins, as the warm ischaemia time for the cord is 20-30 mins; * high level of thoracic cross-clamping; * emergency surgery (eg acute dissection or rupture when there are no collaterals); * greater longitudinal extent of the aneurysm; * patient age greater than 70 years; and, * no prophylactic measures undertaken Intraoperative methods of spinal cord protection include -swift surgery, with identification and preservation of vital cord supply blood vessels -cross-clamp times of less than 30 minutes -Lumbar CSF drainage to increase the spinal cord perfusion pressure -mild hypothermia (34-35 °C), which decreases the cerebral metabolic rate for oxygen by 20% -Preliminary reports suggest intrathecal papaverine may provide some cord protection, as a result of its arteriolar vasodilating, calcium channel blocking and oxygen free radical scavenging properties -Spinal cord somatosensory evoked potential (SSEP) monitoring has been recommended to detect spinal cord ischaemia , Shunts to improve perfusion distal to the cross-clamp have not influenced the incidence of paraplegia, due to the high resistance to retrograde flow in the ASA above the artery of Adamkiewicz inflow. |
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Describe the effect on ventilation/oxygenation with these misplaced DLT.
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AL = correct positioning of the a left sided DLT
BL = L DLT too far in, resulting in ventilation of left lower or left upper lobe through the bronchial lumen, hypoxemia CL = L DLT no for in enough, resulting in partial obstruction when ventilating through the tracheal lumen DL = intubation of operative lung, resulting in severe hypoxemia when ventilating through bronchial lumen, but improvement during ventilating through tracheal lumen. BR = introduced to far, resulting in ventilation of right middle and right lower lobe only, right upper is not ventilated, resulting in hypoxemia |
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AT08c [Apr97] [Jul98] [2001-Apr] Q50, [2001-Aug] Q31, [2003-Apr] Q3, [2003-Aug] Q54, [2005-Apr] Q38, [Jul05] [Mar06]
The most appropriate method for improving oxygenation during one lung anaesthesia, after institution of an FiO2 of 1.0, is application of A. 5cm H2O CPAP to the non-dependent lung B. 10cm H2O CPAP to the non-dependent lung C. 5cm H2O PEEP to the dependent lung D. 5cm H2O CPAP to the non-dependent and 5cm H2O PEEP to the dependent lung E. intermittent re-inflation to the non-dependent lung |
ANSWER C
OLV used for almost all thoracic operations : lung, esophageal, aortic or mediastinal surgery, to improve surgical access. Although one lung is ventilated, both lung are perfused. Resulting in -trans pulmonary shunting -impairment of oxygenation -hypoxemia Treatment of hyoxemia during OLV 1. Increasing FiO2 -effective in immediately treating -will not improve with shunt fractions > 40% 2. Check position of DLT (using FOB) 3. ensure adequate CO, reduce volatile to <1MAC 4. Apply recruitment maneouvre 5. Apply 5cm H2O PEEP to dependent lung 6. Apply 1-2cm H2O CPAP to non-dependent lung after recruitment maneouvre 7. Intermittent Reinflation 8. Partial ventilation techniques including oxygen insufflation, HFJV, mechanical obstruction of blood flow to non-dependent lung 9. clamp pulmonary artery of non ventilated lung (rare) |
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AT15 [Apr97] [Apr98] [Jul98] [Apr99] [Aug99] [2003-Apr] Q66, [2003-Aug] Q30, [Mar06] ANZCA version
Q42 The patient most likely to desaturate significantly during one lung anaesthesia is one who is having A. a left sided thoracotomy, has reasonable PaO2 values during two-lung ventilation, but poor pre-operative spirometry B. a right-sided thoracotomy, has relatively poor PaO2 values during two-lung ventilation but good pre-operative spirometry C. a left-sided thoracotomy and has diminished perfusion but not ventilation to the operative lung on a V/Q scan D. a right-sided thoracotomy, has relatively poor PaO2 values during two-lung ventilation and poor pre-operative spirometry |
ANSWER B
OLV used for almost all thoracic operations : lung, esophageal, aortic or mediastinal surgery, to improve surgical access. Although one lung is ventilated, both lung are perfused. Resulting in -trans pulmonary shunting -impairment of oxygenation -hypoxemia Prediction of Hypoxemia during OLV 1. Side of operation -size R>L -therefore operation on left lung (ei larger right lung is dependent and ventilated) results in better oxygenation -FiO2 1, results in 280mmHg for left sided operation and 170mmHg for right sided operations 2. Lung Function Abnormalities a. airway obstruction with low FEV1 results in better oxygenation during OLV, perhaps due to autoPEEP resulting in reduced atelecatasis and improving oxygenation b. low PaO2 on pre-operative ABG is a predictor for hypoxemia during OLV. 3. Distribution of perfusion - less perfusion of non ventilated lung and more to ventilated lung results in high PaO2 during OLV a. large tumors in non ventilated lung = better PaO2 as they present for lobectomies or pneumonectomies b. gravity, if ventilated lung is dependent = better PaO2; in one study in COAD pts, FiO2 1.0 resulted in PaO2 300mmHg in supine versus PaO2 490mmHg in lateral |
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AT23 [2003-Apr] Q105, [2003-Aug] Q86, [2004-Aug] Q95, [2005-Apr] Q86, [Jul05] [Mar06] ANZCA version
Q106 Complications, which usually present early following pneumonectomy, include all of the following EXCEPT A. Broncho-pleural fistula B. Respiratory failure C. Right heart failure D. Right to left shunt E. Supraventricular arrhythmia |
ANSWER A
Pneumonectomy is the surgical removal of an entire lung -mainly for bronchogenic carcinoma in main stem bronchus -rarely for pulmonary metastases, pulmonary tuberculos, fungal infections and broncheicatasis, traumatic lung injury, congential disease and bronchial obstruction IMMEDIATE Contralateral pneumonthorax Sputum retention Prolonged air leakage Haemorrage Phrenic nerve injury R-L shunt through PFO due to increase in PA pressures Acute respiratory insufficiency EARLY A. Respiratory : -ARDS/post pneumonectomy pulmonary oedma - treatment is supportive, mortality>50% -hemothorax, chylothorax -empyema B. Cardiac -arrthymias AF -AMI -PE -Cardiac herniation LATE A. postpneumonectomy syndrome -extrinsic compression of distal trachea and mainstem bronchus due to shifting of the mediastinum -progressive dyspnea, cough, inspiratroy stridor, recurrent pneumonia after 6 months of surgery -treatment surgical repositioning of mediastinum B. Bronchopleural fistula -1.5-4.5%, mortality of 30-70% -assocaited with empyema C. Esophagopleural fistula |
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SC13 [2003-Apr] Q89, [2003-Aug] Q58, [Jul05] [Mar06]
The most appropriate investigation to diagnose Type A aortic dissections in potentially unstable patients is A. angiography B. CAT scan C. magnetic resonance imaging (MRI) D. transoesophageal echocardiography E. transthoracic echocardiography |
ANSWER D
Patient is potentially unstable. |
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SC26 [Mar06] [Jul06] ANZCA version
Q147 A patient is scheduled for emergency coronary artery bypass surgery (CABG) 2 hours after receiving tirofiban (Aggrastat) during coronary angiography and an unsuccessful coronary stenting procedure. The most useful strategy to treat or prevent excessive perioperative bleeding is: A. administration of concentrated Factor VIII B. administration of cryoprecipitate C. delaying surgery another 2 hours D. haemofiltration during cardiopulmonary bypass E. platelet transfusion |
ANSWER E
Tibrofiban (Aggrastat) is an antiplatelet agent -Gycoprotein IIb/IIIa inhibitor (block the final common pathway of platelet aggregation) -does not block platelet adhesion, screction of platelet products, inflammatory effects or thrombin activation Used in the management of STEMI or unstable angina in patients awaiting PCI Parental dosage -2.5mg in 250ml NS (50mcg/ml) -Loading dose 0.4mcg/kg/min for 30 minutes -Maintenance of 0.1mcg/kg/min for up to 72 hours -Infusion should continue through PCI and 12-24 hours after -Stop for 8 hours prior to CABGs Rapid onset and short duration of action -coagulation returns to normal after 4-8 hours of ceassation -half life 2 hours Contraindications -hypersensitivity -active bleeding -history of ICH, AV malformation, aneurysm -thrombocytopenia induced by tibrofiban in past -CVA in last 30 days -recent surgery -suggestive funding of aortic dissection Complications -major bleeding : ICH, retroperiotoneal, pulmonary, spinal-epidural haematoma -anaphylaxis -thrombocytopenia |
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ANZCA March 2006 Q71.
During elective major vascular surgery the best way to reduce the risk of acute renal failure is to maintain a normal A. central venous pressure B. mean arterial blood pressure C. renal blood flow D. systemic vascular resistance E. urine output |
ANSWER C
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Describe the effects of the level of aortic occlusion on changes in CVS variables
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Proximal decending Aox
MAP : increased 35% CVP : increased 56% Mean PAP : increased 43% PWCP : increased 90% (due to blood volume distribution and increased afterload) CI : decreased 30% HR : no change LV stroke work : no change Supracaeliac AoX MAP : increased 54% PCWP : increased 38% EF : decreased by 38% LV end-systolic area : increased 69% LV end-diastolic area : increased 28% Wall motion changes in 92% New AMI : 8% Suprarenal AoX cause similar but smaller CVS changes. Infrarnal AoX associated with only minimal change and no wall motion abnormalities |
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Describe the cardiovascular response to aortic unclamping.
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Systemic hemodynamic response to aortic unclamping. AoX = aortic cross-clamping; Cven venous capacitance; R art = arterial resistance; Rpv = pulmonary vascular resistance; [arrow up] and [arrow down] = increase and decrease, respectively.
G. Response to unclamping -SVR and MAP decrease by 70-80% -CO may increase, decrease or remain unchanged -LV end-diastolic pressure decreases -myocardial blood flow increases -flow through the terminal aorta and femoral arteries increases -reactive hyperemia due to both metabolic and hormonal responses, lasting 15 minutes -washout distal to the AoX occurs returning vaso and cardio-depressant compounds -blood redistribution to vessels distal to AoX decrease venous return, cardiac output and MAP (hypovolemia) To minimize cardiovascular responses 1. Gradual release of aortic clamp and reapplication : slow down the washout 2. Volume replacement 3. Sodium bicarbonate adminstration |
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SZ18 [2004-Aug] Q147, [2005-Apr] Q76, [Mar06] ANZCA version
Q148 Infra-renal aortic cross-clamping usually results in A. decreased cardiac contractility B. decreased coronary blood flow C. decreased renal blood flow D. minimal change in cardiac output E. increased heart rate |
ANSWER D
Systemic haemodynamic response to aortic cross-clamping -preload does not always increase -infra-renal aortic cross-clamping blood volume shifts into splanchnic circulation and preload does not increase MAP : no change PAP : no change End-diastolic area : increase 9% End-systolic area : increases 11% Abnormal wall motion : 0 New AMI : 0 |
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Describe the cardiovascular response to aortic clamping.
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A. Primary variables
-MAP increases -SVR increases -HR no change -CO generally decreases, but increases in thoracic AoX B. Afterload, Preload and Blood volume redistribution -impedance to aortic flow : increased afterload in all Aox -preload changes depends on level of Aox -thoracic AoX : passive recoil and emptying of capacitance vessels (both splanchnic and lower limbs) into the systemic circulation results a marked increased in preload and therefore cardiac output -CVP, PWCP, LV end-diastolic area all increase depending on the level of AoX -this effect is abolished if the IVC is clamped or blood is removed from the system (ei. phebotomy) -differences in CVS response after AoX at difference levels is explained by different degrees and patterns of blood volume distribution -infracaelic Aox maintains the splanchnic circulation, blood is redistributed to these capacitance vessels and preload is not significantly changed -however this response depends on the sympathetic discharge to the splanchnic system, activation of the SNS may decrease venous capacitance resulting in increased preload 3. Metabolism -reduced total body oxygen consumption -thoracic AoX results in 55% reduction -anaerobic metabolism in tissues below Aox -reduced O2 uptake in tissues above AoX -proximal hypervolemia, vasodilation and increase in flow through these tissue may result in microcirculatory disturbances which jeopardize oxygen exchange -activation of SNS constricts arterioles and decrease capillary flow results in shunting of blood away from tissue beds (possibly similar to hyperdynamic state in sepsis) -Increase in mixed venous O2 sat (SVO2) D. Coronary blood flow and myocardial contractility -Aox increases both preload and afterload, leading to an increase in myocardial oxygen demand -autoregulation : an increase in demand is met by an increase in supply by increasing coronary blood flow -thoracic AoX 65% increase in CBF -myocardial contractility is initially increased due SNS stimulation and physiological repsonse to increases in preload and afterload -gradual decrease due to accumulation of cardiodepressant metabolites (H+, K+, adenosine) from ischaemic tissues E. Duration of AoX -with increased duration, SVR increases, while CO decreases -possibly explained by capillary leak and reduction in circulating blood volume -also release of cardiodepressant metabolites F. Haemodynamic response distal to AoX -aortic pressure decreases -distal pressure is directly dependent on proximal aortic pressure through existing collateral vessels, therefore, proximal and distal aortic pressures must be maintained as great as the heart can withstand, otherwise a temporary shunt inserted. -a decrease in arterial and subsequently, capillary pressure below AoX results in absorption of interstitial fluid (Starling's forces) -this mat increase venous return and circulating volume above AoX |
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Describe the non-cardiovascular responses to AoX.
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A. Hormoral changes
1. Metabolic Lactic Acidosis -degree of acidosis depends on degree of disease, time of AoX, level of AoX, collateral vessels 2. RAS -activation of renin-angiotension system -suprarenal AoX results in reduced perfusion pressure in the afferent arterioles of the kidney -infrarenal AoX also increases RAS but the mechanism is less clear -?activation of SNS -?effect of prostaglandins 3. Catecholamines and SNS -thoracic AoX is consistently associated with large increases in adr and norad concentration -lower levels are associated with smaller increases in blood catechols -adr increases during clamping -norad increases after unclamping -mechanism s complex and multifactoral : hypotension, shock, direct ischemic excitation of spinal cord and adrenal medulla. 4. Free oxygen radicals -hypoxic conditions, the metabolism of adenosine triphosphate produces adenosine, hypoxanthine, xanthine oxidase, purines, and oxygen free radicals. 5. Prostaglandins -increase during and after clamping -PGE, TXA A2 and TXA B2 -increased production of vasodilating prostaglandins during aortic cross-clamping -vasoconstricting prostaglandins during unclamping 6. Platelets and neutrophils -sequestration in lung -attributable to anaerobic metabolic products and microaggregates released from the ischemic tissues -Lymphocyte count decreases, whereas leukocyte and neutrophil counts increase, after unclamping of the aorta 7. Complement activation -concentrations of the anaphylatoxins C3a and C5a increased -Epidural anesthesia virtually prevented an increase in C5a and significantly modified an increase in C3a -mechanism is unclear 8. Other -increase in IL-1 and IL-6 due to increased sheer stress on endothelium -increase in TNF due to ischemia B. Respiratory -increase in PVR especially during thoracic AoX -mainly due to blood redistribution -neutrophil sequestration and accumulation of microaggregates results in pulmonary edema -can progress to ARDS which carries a high mortality C. Kidneys -infrarenal 5% incidence of renal failure requiring haemodialysis, associated large increase in renal vascular resistence and 30% decrease in renal BF -suprarenal 15% -thoracic 50% incidence of RF, severe 85-95% decrease in renal BF, GFR and UO -renal failure always results from ATN -ischemia-reperfusion insult D. Spinal Cord -incidence of paraplegia is 0.4-40% -depends on urgency of operation, the presence of aortic dissection, hypotension, the age of the patient, and the duration and level of the aortic cross-clamping (<30min prefered) -Approximately half of the patients with initial paraplegia make no neurologic recovery -mechanism is due to decrease in spinal perfusion pressure -survival depends on collaterial arteries and communications : Artery of Adamkewicz -spinal perfusion pressure is made worse by blood volume shifts, which increase cerebral blood volume = increase in ICP -therapeutic role of lumbar spinal drain to reduce CSF volume -cooling E. Abdominal viscera -The reported incidence of visceral ischemia varies from 1-10%, with mortality exceeding 50%. -The most common site of ischemia is the left part of the colon. -Hypovolemia, thrombosis, cardiac insufficiency, and microembolism should also be considered in the development of bowel ischemia |
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Classify aortic dissections.
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DeBakey
-based on where the original intimal tear is located and the extent of dissection * Type I – Originates in ascending aorta, propagates at least to the aortic arch and often beyond it distally. * Type II – Originates in and is confined to the ascending aorta. * Type III – Originates in descending aorta, rarely extends proximally but will extend distally. Standford * A – Involves the ascending aorta and/or aortic arch, and possibly the descending aorta. The tear can originate in the ascending aorta, the aortic arch, or, more rarely, in the descending aorta. It includes DeBakey type I, II and retrograde type III[6] (dissection originating in the descending aorta or aortic arch but extending into the ascending aorta). * B – Involves the descending aorta (distal to left subclavian artery origin), without involvement of the ascending aorta or aortic arch. It includes DeBakey type III without retrograde extension into the ascending aorta. |
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What are the advantages and disadvantages of a endoluminal AAA repair
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TBA
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SC28 ANZCA Version [Jul06]
Q143 A 25-year-old man with Marfan's syndrome is scheduled for aortic arch reconstruction under circulatory arrest. Cooling to 18 degrees is planned. The maximum time for circulatory arrest at this temperature after which the risk of long term neurological injury increases markedly is A. 15 minutes B. 25 minutes C. 35 minutes D. 45 minutes E. 55 minutes |
ANSWER B
Hypothermic cardiac arrest at18°C provided electrocerebral silence is obtained, rewarmed correctly and hemodynamic stablity <30 minutes : safe <40 minutes : safe or transient neurological dysfunction >40 minutes : neurological deficit is prone to occur especially in high risk (elderly, diabetes, hypertension) -further cooling of the brain to 13°C to 15°C reduces the risk again how careful rewarming with close monitoring must occur Oxford states -45 min in adults -60 min in neonates |
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SC29 ANZCA Version [Jul06] Q120
A 40-year-old man with Marfan's syndrome has undergone successful thoracoabdominal aortic reconstruction for aortic dissection. He has a CSF (cerebrospinal fluid) drain in situ. 48 hours post-operatively the CSF is noted to be bloodstained and he becomes obtunded. The most appropriate urgent investigation is A. CSF microscopy and culture B. MRI (magnetic resonance imaging) brain C. MRI spine D. non-contrast head CAT scan E. serum electrolytes |
ANSWER D
Decreased CSF pressure from drainage causing stretching then tearing of fragile subdural veins and consequent development of SDH Marfan is associated with intracranial aneurysms and lowering pressure in the CSF compartment via lumbar drain increases the transmural pressure gradient in the aneurysm (if there is one), hence increases the risk of rupture. |
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AC132 [2004-Aug] Q136, [Jul06] ANZCA version Q76
During surgery for tracheostomy insertion, surgical diathermy is being used at the tracheal incision. You are ventilating with 100% oxygen. As the trachea is opened you notice a blue flame shooting up from the incision. Your first action should be to A. disconnect the breathing circuit from the endotracheal tube B. douse the wound with saline C. insert a tracheostomy tube D. remove the endotracheal tube E. turn off oxygen and ventilate with air |
ANSWER A
Miller covers this under laser anaesthesia airway fire protocol chapter 67: 1. remove source of flame (Surgeon) 2. stop ventilation (Anaesthetic) 3. disconnect breathing circuit 4. extinguish with bucket of water, flood oropharynx, consider flushing saline down ETT to extinguish intraluminal fire 5. consider removing ETT and ventilate with 100% O2 via face mask (doesn't actually talk about removing the ETT but I got the impression this is when it would be taken out - when no flame, no gas to combust) 6. re-intubate and assess damage and remove debris - direct laryngoscopy, rigid bronchoscopy, +/- gentle lavage and distal FOB 7. If damage, retube and if severe damage may need low tracheostomy 8. Consider steriods and antiobitcs 9. Post event CXR Prevention of airway fires for surgeric tracheostomy insertion : The following anaesthetic and surgical recommendations are suggested. * Anaesthetic 1. Use the minimum concentration of oxygen to maintain arterial saturation. 2. Use other non-oxidizing agents such as helium, air or nitrogen in place of nitrous oxide. 3. Position the ETT near the carina to minimize exposure of the cuff to injury in opening the trachea. 4. A good seal on the cuff is essential to prevent leaking of anaesthetic gases. 5. Fill the cuff with water to act as a fire retardant. 6. Consider using fire resistant ETT (silicone/metallic) often used in laser surgery. * Surgical 1. Minimize use of diathermy particularly once the trachea is opened. 2. Use bipolar diathermy if bleeding occurs once the trachea is opened. 3. Use suction to remove oxygen rapidly from the field. 4. Surround the operating field with moist pack if diathermy has to be used. 5. Always have sterile saline at hand in case of fire. |
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AT20b ANZCA Version Jul06] Q77, [Apr07] Q73
Major complications of mediastinoscopy include all of the following EXCEPT A. compression of the great vessels B. air embolism C. pneumothorax D. major haemorrhage E. phrenic nerve damage |
ANSWER A
Complications of mediastinoscopy * Death * MAJOR complications Major haemorrhage Tracheobronchial laceration Oesophageal perforation Recurrent nerve paralysis Phrenic nerve paralysis Thoracic duct injury Cerebrovascular accident Mediastinitis Venous air embolism Tumour implantation * MINOR complications Pneumothorax Superficial wound infection Recurrent nerve paresis Minor bleeding Autonomic reflex braydcardia Mediastinal lymph node necrosis Compression of the great vessels occurs and warrents invasive blood pressure monitoring, however it is rarely a complications as it is transient. |
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AT26 ANZCA Version [Jul06] Q101, [Apr07] Q101
Following one-lung ventilation there is an increased risk of lung injury if plateau airway pressure (during one-lung ventilation) exceeds A. 20 cm water B. 30 cm water C. 40 cm water D. 50 cm water E. lung injury is not related to ventilation pressure |
ANSWER B
BJA CEPD article on OLV states that " tidal volume of 10ml/kg suggested , if airway pressure is excessively high (>30cmH20), the tidal volume should be reduced and respiratory rate increased...permissive hypernapnia to spare barotrauma should be considered |
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AT27 ANZCA March 2007 Q108.
Following a left sided pneumonectomy, a left intercostal drain is placed and connected to an underwater drainage system. In the postoperative period A. a leakage of air is expected from the drain B. the patient should be nursed in the right lateral decubitus position C. the underwater seal drain should be left on continuous free drainage D. the underwater seal drain should be left on continuous free drainage, and connected to wall suction for 5 minutes every hour E. the underwater seal drain should remain clamped and be released for a short period every hour |
ANSWER E
Post-pneumonectomy an ICC is rarely placed However, when an ICC is placed it should be clamped and release intermittently. -it should NEVER be placed on suction as it will cause mediastinal shift and cardiac herniation. If cardiac hernation should occur, patient should be turned non operative side down and chest drain open to air. |
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SC30 ANZCA March 2007 Q114.
In preparation for a posterior-lateral incision for a thoracotomy, a patient is placed in the left lateral decubitus position. In this position the A. axillary roll is placed under the chest to aid surgical exposure B. dependant leg should be extended and the superior leg flexed C. neck should be extended to allow access to the airway D. radial nerve is the most commonly injured nerve E. right brachial plexus is at risk of injury if the right arm is flexed at the shoulder to more than 90deg |
ANSWER B E
A. FALSE : axillary roll is placed to remove pressure of the humoral head and reduce the risk of brachial plexus injury B. FALSE : both hips flexed 30-40deg C. FALSE D. FALSE : Ulnar nerve E. TRUE : shoulders should be kept at 60-80deg RF in positioning for ulnar nerve injury include -abduction ->90deg shoulder flexion -shoulder extension |
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ANZCA March 2007 Q109.
Relative contra-indications to mediastinoscopy include A. cervical spondylosis B. emphysema C. mediastinal lymphadenopathy D. poor left ventricular function E. superior vena cava syndrome |
ANSWER E
Previous mediastinoscopy is a relatively strong contraindication to a repeat procedure because scar tissue eliminates the plane of dissection. Relative contraindications -Superior vena cava (SVC) syndrome increases the risk of bleeding from distended veins -severe tracheal deviation -cerebrovascular disease, -severe cervical spine disease with limited neck extension -stroke -previous chest radiotherapy -thoracic aortic aneurysm. |
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ANZCA July 2007 Q139
You have anaesthetised a patient with a partially obstructing right main bronchus tumour. You are using Heliox (28% 02/72% He) and sevoflurane. You secure the airway with an endotracheal tube and continue with the same gas mixture. After 20 minutes the end-tidal CO2 is 28 mmHg. The capnogram waveform is normal. This probably means the patient Is A. appropriately ventilated with a low cardiac output B. appropriately ventilated with a normal cardiac output C. hypothermic (340 C) D. hyperventilated E. hypoventilated |
ANSWER B
Helium absorption of IR light interferes with measured ETCO2. Therefore it underestimates. |
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FE32 [Jul07]
Post-thoracotomy the drain is leaking fluid with protein, fat, lymphocytes etc. What could be the cause? A. Bleeding B. Thoracic duct injury C. sympathectomy D. Pleural fluid E. ?? "something like CHF or pulmonary oedema" |
ANSWER B
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PP29 [Mar91] [Aug91] [Mar92] [Aug96] [Jul98]
Tracheo-oesophageal fistula: A. Diagnosed reliably by failure to pass a soft tube into the stomach B. Should all be intubated soon after birth to reduce aspiration C. Intercostal blocks are contraindicated for postop pain relief after repair because of local anaesthetic toxicity risk D. Associated with renal abnormalities |
A False because in H fistulas you still can pass the nasogastric tube
B False because aspiration can still occur following intubation - still have a fistula. Secondly intubation is indicated for respiratory failure (spontaneous breathing is the goal. IPPV can often leads to preferential insufflation of the gut due to lower resistance that leads to respiratory embarrassment), surgery or post surgical recovery for example. C False? I cannot see any contraindication if dosage is in the non toxic range. Also re above "pneumothorax would be a disaster"; if they had a TOF they would often approach with a R thoracotomy and usually an ICC is placed after a thoracotomy? D True. TOFS can be associated with renal abnormalities as in part of the VACTERAL syndrome - vertebral, anal, cardiac, TOF (or TE), renal AND limb anomalies |
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AT21 ANZCA version [2001-Apr] Q86, [2001-Aug] Q7, [2002-Aug] Q132, [2003-Apr]
During one-lung ventilation, hypoxic pulmonary vasoconstriction in the non-ventilated lung A. is increased with high pulmonary artery pressures B. is decreased by applying CPAP (continuous positive airway pressure) to the non-ventilated lung C. reduces the shunt fraction by approximately 40% D. is reduced significantly by isoflurane E. is unaffected by hyperventilation |
ANSWER B
* A. is increased with high pulmonary artery pressures - false * B. is decreased by applying CPAP to the non-ventilated lung - maybe true; CPAP will decrease the amount of shunted blood definitely, but does its application actually recruit alveoli and improve V/Q ratio?? * C. reduces the shunt fraction by approximately 40% - maybe true: 50% is quoted figure * D. is reduced significantly by isoflurane - false * E. is unaffected by hyperventilation - probably false: pulmonary vessel tone is affected by hyper/hypocapnoea. |
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AZ-12. April 2008
CT reprint showing large MNG. Uppermost concerns to anaesthetist is a. Involvement of the Right carotid artery b. Tracheal deviation to the left c. Tracheal deviation to the right d. Malignant involvement of the paratracheal nodes e. compression of upper lobe of rt.lung |
ANSWER B
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AT28 April 2009
You intubate a young male patient for a left thoracotomy with a 39FG Robert Shaw tube. When you inflate both cuffs and ventilate the bronchial lumen you get left sided ventilation. When you attempt to ventilate the tracheal lumen the pressures are very high and you get no air entry. Yet when you deflate both cuffs you can ventilate the patient through the tracheal lumen. The most appropriate step to take next is: A. Change to a 41FG tube B. Change to a 37FG tube C. Deflate both cuffs and insert further cm and recheck D. Deflate both cuffs and withdraw a few cm and recheck E. Pull ETT out and start again. |
ANSWER C or D
C. is true if the bronchial cuff has herniated into the carina. It needs to be pulled back. D. is true if the entire tube is endobronchial. It needs to be pulled back. |
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AT April 2009
A patient comes to see you in clinic for a pneumonectomy for SCLS. His spirometry shows an FEV1 of 2.5L (>40% predicted). What do you advise about his fitness for surgery? A. He is not fit for the procedure B. He is fit for the procedure C. He needs referral for formal exercise testing D. He needs a blood gas |
ANSWER C
ppoFEV1 = 2.5 x 0.5 = 1.25L -he requires further testing Algorithms from the British Thoracic Society and American College of Chest Physicians. -initial screening tool is preoperative FEV1 -FEV1 >2L for pneumonectomy -FEV>1>1.5L for lobectomy If these threshold lung volumes are not present -full respiratory testing to calculate ppoFEV1 and DCLO -both need to be >40% and O2 sat>90% on RA If both ppoFEV1 and DLCO are <40%, then CPX testing -VO2 max <15 ml/kg/min delineates between high and medium risk patients |
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Predictors from poor outcome for lung resection.
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1. Age
-more a factor in pneumonectomy 2. Cardiovascular fitness a. AHA/ACCF perioperative cardiovascular risk stratification b. further investigations and optimization 3. Nutrition -weight loss >10%, low BMI and low serum albumin are indicators advanced disease -increased risk of post operative complications 4. Performance status -Duke's socring system ->4 METS required 5. Respiratory function a. Spirometry to determine pre operative FEV1 and DCLO -calculate ppoFEV1 and ppoDCLO -threshold ppoFEV1 is 800ml for lung resection -mortality increases when ppoFEV and ppoDCLO is <40% predicted b. Ventilation/perfusion scanning -inhalation of radioactive xenon and IV adminstration of technetium labelled macroaggregrates -a gamma camera and computer determine the uptake of radiactive ions or perfusion of technetium -Postop FEV1 = Preop FEV1 x % radioactivity of the non-operated lung c. ABG -independent of PCO2 -preoperative hypoxaemia, O2 Sat<90% and desaturation>4% with exercise is associated with risk of complications. d. Exercise stress testing -VO2 max >20ml/kg/min indicated no risk of complications or death <15 ml/kg/min indicates increased risk of complications <10 ml/kg/min indicates mortality rates of 40-50% Equivalents 3 flights of stairs = FEV1>1.7L 5 flights of stairs = FEV1>2L = VO2 max >20ml/kg/min Unable to climb 1 flight = VO2max<10ml/kg/min |
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How would you calculate predicted postoperative lung value?
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Based on the numbers used in Miller -Total 42 segments
-22 segments in the right lung RUL=6 RML=4 RLL=12 -20 in the left lung LUL=10 LLL=10 A right lower lobectomy will remove 12 segments, and we will be left with 30. ppoFEV1=30/42 x 2.4L = 0.7143 x 2.4L = 1.71L. |
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Black bank April 2009
On bypass, for mitral stenosis repair immediately after cardioplegia the following happens: MAP to 25 SvO2 80% CVP1 Next step in management: A) metaraminol B) give volume C) increase pump flows D) adrenaline infusion E) |
ANSWER A
This scenario is common, it is all about finding the right balance in circulating volume, pump flow and vascular tone. At the time of cardioplegia, you should be running full flow and therefore volume status should be optimised. |
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Black Bank April 2009
Redo CABG following median sternotomy surgeon states he has accidentally cut a vein graft, immediately followed by ST elevation on ECG and VF, next action. A) External defibrillation 200J (Biphasic) B) Heparin IV then femoral cutdowns for bypass C) Hand ventilate with 100% oxygen D) GTN infusion E) metaraminol |
ANSWER ?B
Part of the heart is completely ischaemic. In this specific instance, crashing onto bypass is the most appropriate intervention. |
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Black bank April 2009
Mitral valve replacement for Mitral stenosis. Pulmonary artery catheter in situ. Following separation from bypass, copious frank haemoptysis via ETT. Next step in management" A) Insert double lumen tube B) Go back on bypass C) Give protamine D) Deflate and pull back PAC E) Perform fibreoptic bronchoscopy |
ANSWER B
Pulmonary artery rupture as a consequence of PAC. In this case going back on bypass to circumvent the lungs. Non surgical -Immedate treatment involves deflating the PAC ballon, withdrawing 1-2 cm and then reinflating to tamponade the bleed -A double lumen tube should be inserted for isolation and ventilation of the good lung. -Bronchoscopy and insertion of Fogerty cather tamponade -Injection of autologous blood clot through catheter to seal puncture Surgical options -thoracotomy with lobectomy, pneumonectomy, hilar clamping with direct arterial repair -haemothroax is a strong indication for surgical repair Risk factors for rupture ->60 years old -pulmonary hypertension -improper balloon inflation -improper catheter positioning -cardiopulmonary bypass -anticoagulation |
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Black Bank April 2009
70 year old man having lung resection for SCC of left lung FEV1 2.3L (? % predicted), FVC 3.5L (? % predicted). Do you... A. Accept for lobectomy or pneumonectomy B. Decline pneumonectomy, proceed to lobectomy C. Cardiopulmonary exercise testing D. Differential V/Q scan E. Decline both pneumonectomy and lobectomy |
ANSWER A
Algorithms from the British Thoracic Society and American College of Chest Physicians. -initial screening tool is preoperative FEV1 -FEV1 >2L for pneumonectomy -FEV>1>1.5L for lobectomy If these threshold lung volumes are not present -full respiratory testing to calculate ppoFEV1 and DCLO -both need to be >40% and O2 sat>90% on RA If both ppoFEV1 and DLCO are <40%, then CPX testing -VO2 max <15 ml/kg/min delineates between high and medium risk patients |
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Black bank March 2010 TMP-108
A 60yo Man with anterior mediastinal mass, during induction for mediastinoscopy....lose cardiac output, decreased saturations, drop in ETCO2. Management A. Adrenaline B. CPR C. CPB D. Place prone |
ANSWER D??
Immediate sternotomy and elevation of mediastinal mass would be the best answer if available. Management of mediastinal mass Preoperative -establish anatomy : CT chest -establish pathology : most likely lymphoma but also thymoma, germcell tumor granuloma, bronchogenic carcinoma, thryoid tumor, bronchogenic cyst and cystic hydroma -intended surgery : diagnostic or therapeutic; sternotomy, thoracotomy, cervical mediastinoscopy, anterior parasternal mediastinoscopy, VATS -occasionally maybe for ermergenct surgery such as AAA or LUSCS -signs or symptoms that include chest pain or fullness, dyspnea, cough, sweats, superior vena cava obstruction, hoarseness, syncope or dysphagia -increased perioperative risk are increased dyspnea (orthopnea) or cough when supine (increased risk of airway complications) and syncopal symptoms or pericardial effusion (increased risk of cardiovascular complications). -does this patient need a GA? LA for anterior mediastinoscopy, needle biopsy, thoracentesis Intraoperative -step-by-step induction and continuous monitoring of gas exchange and haemodynamics (IAL) -maintain breathing with inhalation induction with sevoflurane or propfol-remi TIVA -possible AFO if there is non compressed trachea -development of airway or vascular compression requires the patient to be awakened as rapidly as possible -intraoperative lifesaving techniques Airway : repositioning or rigid bronchoscopy and ventilation distal to obstruction CVS : immediate sternotomy and surgical elevation of mass off he great vessel |
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Black Bank March 2010
47.Inserted DLT. FOB down tracheal lumen. What feature is most helpful in identifying Left vs Right main bronchus A. Trachealis muscle B. "there are 3 lobes in right lung" C. LMB longer than right D. Angle of RMB vs left E. Three segments of RUL |
ANSWER E
* A - False. Trachealis muscle divides at carina and continues in each main bronchus, so not particularly helpful. BUT ..I thought trachealis was only located posteriorly connecting the ends of the C-shaped cartilage. If you know whats the front and whats the back wouldnt this make it easy to figure out L from R ? - Isoma * B - False. While there are indeed 3 lobes in the right lung, that fact is not helpful to determine which is right or left main bronchus. * C - True. The LMB is about 5cm long before it gives off any subsequent lobar bronchi, whereas the RMB gives off a lobar bronchus (the RUL bronchus) about 2.5cm from the carina. This can help to determine between RMB and LMB. * D - ? False. While there is a difference in the angle (from the vertical) of the LMB and RMB, I don't know if this would be significantly appreciable bronchoscopically. Anyone? * E - True. The RUL bronchus has a trifurcation for each of the RUL segments, and this may also be useful in determining which side you are on. |
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Black Bank March 2010
48.You are performing a bronchoscopy, but are unsure of your location. Then you see trifurcation of bronchi. Most likely location is: A. Right upper lobe B. RML C. RLL D. LUL E. Lingula |
ANSWER A
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March 2010
75.Which can deliver minute ventilation of greater than 5L/min using a 14 G cannula used for needle cricothyroidotomy A. jet ventilation using pressure 400KPA B. oxygen flush button on anaesthetic machine C. oxygen tubing on oxygen port on anaesthetic machine at 12L/min D. E. none of the above |
ANSWER A
The purpose of the study was to measure gas flow rates using different methods of transtracheal ventilation. Wall oxygen flow (WOF) at 10 and 15L/min, and a self-inflating ventilation bag (SIVB) were used to deliver gas flow through three transtracheal catheters: 13, 14, and 16 gauge (5 trials each). WOF mean gas flow rates (L/min) through the 16G, 14G, 13G catheters, respectively were: 15.7, 15.7, 16.8 at 15L/min, 10.5, 10.5, 10.3 at 10 L/min, and 5.7, 7.5, 7.7 via SIVB. SIVB gas flow was not continuous since it required the bag to reinflate, which reduces its calculated flow rate. A 500 cc tidal volume can be delivered within 3 seconds (WOF) and 5 seconds (SIVB). Catheter size did not substantially affect gas flow rates (Poiseuille's law not applicable). Transtracheal ventilation is best done by using WOF, but if a device to perform this is not available, then an SIVB may still be sufficient. |
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123. OLV hypoxaemia. After 100% O2 and FOB next step is: (rpt)
A. CPAP 5cm top lung B. CPAP 10cm top lung C. PEEP 5cm bottom lung D. CPAP 5cm top + PEEP 5cm bottom |
ANSWER C
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August 2010
25. [New] Advantages of bronchial blockers over double lumen tubes: A. Able to achieve lobar isolation B. Lower cuff pressure C. Quicker deflation of isolated lung D. Pneumonectomy E. Lower incidence of malposition |
ANSWER A
Advantages -do not need to change tube ; post op ventilation -use in kids -isolate lobes -no cuff damage -easier to fit in sick patient Disadvantage -smaller lumen -harder to switch bakc to OLV - 2LV -easily dislodged |
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August 201 Q26.
[New] Patient for pneumonectomy. Pre op FEV1 2.4. (Predicted 4.5L) FVC given as well. For R lower lobectomy. Postoperative predicted FEV1 ? A. 1.3 B. 1.5 C. 1.7 D. 1.9 E. 2.2 |
ANSWER C
ppoFEV1 = 2.4 x (44-12)/44 = 1.7 |
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March 2010 Q39.
[New] xray shown of patient post Left pneumonectomy with heart swung to left side. Management: A. Increase PEEP B. Roll onto right side C. Turn on suction to left pleural catheter D. Lung biopsy E. |
ANSWER B
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March 2010 Q28.
You intubate a young male patient for a left thoracotomy with a 39FG Robertshaw tube. When you inflate both cuffs and ventilate the bronchial lumen you get left sided ventilation. When you attempt to ventilate the tracheal lumen the pressures are very high and you get no air entry. Yet when you deflate BRONCHIAL cuff you can ventilate BOTH left and right lungs through the tracheal lumen. The most appropriate step to take next is: A. Change to a 41FG tube B. Change to a 37FG tube C. Deflate both cuffs and insert further cm and recheck D. Deflate both cuffs and withdraw a few cm and recheck E. Pull ETT out and start again. |
ANSWER C
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March 2011 14.
NEW. Post operative left pneumonectomy. What to do with underwater seal drain? A: Nurse patient in R lateral decubitus position B: Expect to see bubbles C: Suction every hour for 5 minutes D: Unclamp drain once an hour for 5 minutes, leave clamp on for the rest of the time E: Leave on free drainage |
ANSWER D
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AT25 ANZCA version [2005-Sep] Q114
In patients undergoing thoracotomy, techniques which reduce the incidence of intraoperative atrial fibrillation include A. hyperventilation B. pre-operative loading with digoxin C. rocuronium, rather than pancuronium D. thoracic epidural bupivacaine E. thoracic epidural morphine |
ANSWER D
Thoracic Epidural Bupivacaine Attenuates Supraventricular Tachyarrhythmias After Pulmonary Resection (Anesth Analg 2001;93:253–9) This reference only compares epidural bupivacaine and epidural morphine, no mention of any of the other options however. |
