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21 Cards in this Set
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[May09][Oct09]
Doing an awake CEA. Patient becomes confused & combative after carotid clamped and opened. Priority is... a) tell surgeon to release clamp b) tell surgeon to place shunt c) induce GA d) give midazolam |
B. Tell surgeon to place shunt
- Ref: OHA and see Anesthesiologist's Manual of surgical procedures. ----------- |
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SZ01 ANZCA version [2002-Mar] Q4, [2002-Aug] Q46, [2005-Apr] Q16, [Jul05] (Similar question reported in [1986] [1987] [1988] [Mar90] [Sep90])
In a patient who has had an arterial embolism in a limb A. it is important to keep the affected limb warm B. heparin should NOT be given C. surgery will almost certainly be required if the muscles of the limb are paralysed D. surgery should be deferred, whenever possible, for at LEAST twenty four hours E. it is important to localise the embolus precisely so that the arteriotomy can be performed directly over it |
C. surgery will almost certainly be required if the muscles of the limb are paralysed
A. it is important to keep the affected limb warm – FALSE - warming will increase metabolic requirements, worsening acidosis and ischaemic injury (remember AAA repair) B. heparin should NOT be given – FALSE - first line treatment iv theraputic C. surgery will almost certainly be required if the muscles of the limb are paralysed – TRUE - paralysis is an indication of severe disease necessitating immediate treatment. D. surgery should be deferred, whenever possible, for at LEAST 24 hours - Clearly not E. it is important to localise the embolus precisely so that the arteriotomy can be performed directly over it – FALSE - usually lodges in characteristic spots, and anyway the approach is usually to incise at a predetermined \spot and fish out whatever you can distally (don’t usually expose the embolus itself) ~~ ----------- H1436-7 ACUTE ARTERIAL OCCLUSION This results in the sudden cessation of blood flow to an extremity. The severity of ischemia and the viability of the extremity depend on the location and extent of the occlusion and the presence and subsequent development of collateral blood vessels. There are two principal causes of acute arterial occlusion: embolism and thrombus in situ. The most common sources of arterial emboli are the heart, aorta, and large arteries. Cardiac disorders that cause thromboembolism include atrial fibrillation, both chronic and paroxysmal; acute myocardial infarction; ventricular aneurysm; cardiomyopathy; infectious and marantic endocarditis; prosthetic heart valves; and atrial myxoma. Emboli to the distal vessels may also originate from proximal sites of atherosclerosis and aneurysms of the aorta and large vessels. Less frequently, an arterial occlusion results paradoxically from a venous thrombus that has entered the systemic circulation via a patent foramen ovale or other septal defect. Arterial emboli tend to lodge at vessel bifurcations because the vessel caliber decreases at these sites; in the lower extremities, emboli lodge most frequently in the femoral artery, followed by the iliac artery, aorta, and popliteal and tibioperoneal arteries. Acute arterial thrombosis in situ occurs most frequently in atherosclerotic vessels at the site of a stenosis or aneurysm and in arterial bypass grafts. Trauma to an artery may also result in the formation of an acute arterial thrombus. Arterial occlusion may complicate arterial punctures and placement of catheters. Less frequent causes include the thoracic outlet compression syndrome, which causes subclavian artery occlusion, and entrapment of the popliteal artery by abnormal placement of the medial head of the gastrocnemius muscle. Polycythemia and hypercoagulable disorders (Chaps. 110 and 118) are also associated with acute arterial thrombosis. Clinical Features ... severe pain, paresthesia, numbness, and coldness develop in the involved extremity within 1 h. Paralysis may occur with severe and persistent ischemia. Physical findings include loss of pulses distal to the occlusion, cyanosis or pallor, mottling, decreased skin temperature, muscle stiffening, loss of sensation, weakness, and/or absent deep tendon reflexes. If acute arterial occlusion occurs in the presence of an adequate collateral circulation, as is often the case in acute graft occlusion, the symptoms and findings may be less impressive. In this situation, the patient complains about an abrupt decrease in the distance walked before claudication occurs or of modest pain and paresthesia. Pallor and coolness are evident, but sensory and motor functions are generally preserved. The diagnosis of acute arterial occlusion is usually apparent from the clinical presentation. Arteriography is useful for confirming the diagnosis and demonstrating the location and extent of occlusion. TREATMENT Once the diagnosis is made, the patient should be anticoagulated with intravenous heparin to prevent propagation of the clot. In cases of severe ischemia of recent onset, and particularly when limb viability is jeopardized, immediate intervention to ensure reperfusion is indicated. Surgical thromboembolectomy or arterial bypass procedures are used to restore blood flow to the ischemic extremity promptly, particularly when a large proximal vessel is occluded. Intraarterial thrombolytic therapy is effective when acute arterial occlusion is caused by a thrombus in an atherosclerotic vessel or arterial bypass graft. Thrombolytic therapy may also be indicated when the patient's overall condition contraindicates surgical intervention or when smaller distal vessels are occluded, thus preventing surgical access. One approach for administering intraarterial urokinase is to give 240,000 IU/h for 4 h, followed by 120,000 IU/h for a maximum of 48 h. Intraarterial recombinant tPA may be administered at infusion rates of 1 mg/h or 0.05 mg/kg per hour. Meticulous observation for hemorrhagic complications is required during intraarterial thrombolytic therapy. If the limb is not in jeopardy, a more conservative approach that includes observation and administration of anticoagulants may be taken. Anticoagulation prevents recurrent embolism and reduces the likelihood of thrombus propagation. It can be initiated with intravenous heparin and followed by oral warfarin. Recommended dosages are the same as those used for deep vein thrombosis (see below). Emboli resulting from infectious endocarditis, the presence of prosthetic heart valves, or atrial myxoma often require surgical intervention to remove the cause. |
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SZ08 ANZCA version [2001-Aug] Q92, [2002-Mar] Q48
The LEAST effective method of protecting the spinal cord during surgery on the descending thoracic aorta is A. reducing the duration of ischaemia B. lowering the CSF (cerebrospinal fluid) pressure C. spinal cord hypothermia D. administration of thiobarbiturate E. use of shunts to bypass the aortic cross-clamp |
D. administration of thiobarbiturate
A. reducing the duration of ischaemia – not mentioned in Miller or Yao but seems obvious. B. lowering the CSF pressure – MAYBE - advocated, routinely used, controversial - Anecdotal reports have been published in which postoperative paraplegia was reversed with placement of a spinal drainage catheter and removal of CSF. C. spinal cord hypothermia – TRUE - reduces metabolic demand by 7% per degree – the most reliable method D. administration of thiobarbiturate – shown to provide significant protection in animal studies but human studies are conflicting E. use of shunts to bypass the aortic cross-clamp – TRUE - when cross clamp time is greater than 30 minutes. ~~ ----------- Paraplegia occurs in up to 10% in thoracic aneurysm repair, up to 40% of dissecting TAA repair. Distal perfusion with extracorporeal support has been shown to reduce the incidence of paraplegia. Some form of bypass is likely to be beneficial when the anticipated cross-clamp time is greater than 30 minutes but is probably not beneficial when cross clamp time is less than 20-30 minutes. CSF pressure often increases by 10-15 mmHg when application of cross clamps, which increases the likelihood of ischaemic spinal cord injury. Despite evidence from some animal studies, the clinical use of this technique is controversial. Hypothermia is probably the most reliable method of neuroprotection. A two fold prolongation of tolerated cross-clamp time is achieved by cooling even to mild hypothermia (34°C). Because the metabolic rate is linearly related to temperature, moderate or profound hypothermia provides even greater protection. Both systemic and local spinal cord cooling (e.g. epidural infusion of cold saline) have been shown to be beneficial. A variety of drugs have been the focus of lab investigation. Barbiturates have been shown to provide significant protection. Corticosteroids were shown to be beneficial in dogs, but only when combined with CSF drainage in humans. Ca channel blockers provided variable results. Other drugs showing promise are NMDA receptor antagonist, magnesium, naloxone (in traumatic injury) Yao p301 Hypothermia has been shown to be effective in protecting against organ ischaemia. Each degree drop in temperature reduces metabolism by 7%, allowing longer periods of ischaemia without significant neurologic sequelae compared with normothermia. Direct spinal cord cooling has also been attempted as a method of prolonging the duration of ischaemia before irreversible ischaemia occurs. Attempts to increase arterial blood flow can be directed at increasing pressure above the cross-clamp, increasing arterial blood pressure below the clamp, decreasing venous pressure or decreasing the compressive forces surrounding the spinal cord. Spinal cord perfusion = arterial blood pressure – cerebrospinal fluid pressure or CVP Decrease in cord compression can be accomplished with drainage of CSF. Placement of a spinal drain allows monitoring of spinal fluid pressure and the ability to drain fluid when the pressure rises. CSF drainage has been advocated for spinal cord protection. In a recent review, no conclusive data was found to support the use of CSF drainage. Among surgeons, CSF appears to be a routine arm of the multifactorial approach to spinal cord protection. Anecdotal reports have been published in which postoperative paraplegia was reversed with placement of a spinal drainage catheter and removal of CSF. Anastomosis of intercostal or lumbar arteries to the graft has been associated with a lower incidence of spinal cord ischaemia. Naloxone, methylprenisolone, magnesium and intrathecal papaverine have all been suggested to protect the cord. Elevated serum glucose leads to poorer neurologic outcome in patients with cerebral ischaemia. |
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SZ09 ANZCA version [2001-Aug] Q75, [2002-Mar] Q20, [2003-Aug] Q44, [2004-Apr] Q5
In cadaveric donor renal transplantation the intra-operative measure most likely to improve immediate graft function and transplant outcome is A. administration of 200 mg frusemide intravenously prior to unclamping of the newly grafted kidney B. aggressive intra-operative volume expansion to central venous pressures of 10-15 mmHg C. administration of 50 g mannitol intravenously prior to unclamping of the newly grafted kidney D. use of a low dose dopamine infusion (2 ug.kg-1.min-1) perioperatively E. administration of 0.8 g.kg-1 albumin intravenously prior to unclamping of the newly grafted kidney |
B. aggressive intra-operative volume expansion to central venous pressures of 10-15 mmHg
Probably the most important determinant of immediate renal function and avoidance of postoperative acute tubular necrosis is the adequacy of perfusion of the transplanted kidney at the time when the vascular clamps are released. CVP should be used to guide fluid therapy. Patients undergoing kidney transplantation tend to have a hypovolaemic state depite abnormally increased total body fluid. In addition, a cadaveric kidney seems to require higher arterial blood pressure and larger plasma volume to initiate diuresis than a normal kidney. Systolic BP is kept around 130-160 mm Hg and CVP around 10-15 cm H2O. Five percent albumin or normal saline can be used to expand plasma volume. Potassium containing solutions are avoided. Normal saline can be used to replace blood loss. Haemodialysis can be used effectively to remove excess fluid postoperatively. ----------- Ref: Anaesthesia for renal transplantation. CEPD Reviews 2001 Volume 1 Number 1 p24-27 Renal Transplant: Major contraindications are Active malignancy or infection, severe vascular disease, other endstage organ failure & recent MI. DM, followed by glomerulonephritis and polycystic kidney disease are the most common indications. 2 year survival of graft is 90% from living & 80% from cadaveric donors. Cross matching involves ABO compatibility, HLA matching & testing donor T cells against stored recipients serum. Preop preparation: * Dialyse patient to within 0.5 kg of ideal weight. * Correct hyperkalaemia & acid base balance. * Avoid hypovolaemia since increases risk of ATN. * Reflux is common so give H2 antagonist, Maxolon & Sodium citrate. * Often prescribed Cyclosporin, Azothioprine & Methylprednisolone ( on induction ) Anaesthetic technique: * GA is technique of choice since ops often take in excess of 2.5 h, CVC insertion may distress patient, regional technique may affect assessment of intravascular fluid status, & about 40% may need conversion to GA. * Protect AV fistula. * 5 Lead monitoring. * CVC essential to guide fluid Mx. MUST keep CVP > 10-12 mmHg. May need +++ fluid to achieve this hence importance of CVP monitoring ( best to use 0.9% Sodium chloride). * May need RSI since Uraemic hence risk of reflux. * Always ETT. Sux increases K by 0.5-0.7 mmol/l so avoid if K is > 5.5 ( may cause cardiac arrest ). Use atracurium or Cis. * Avoid morphine ( M-6-G ) & use fentanyl. * May be asked to give Mannitol 0.5-1g/kg, frusemide or dopamine. |
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SZ10 [Apr07][Jul07][Oct08][Oct09]
The absorption of fluid into the circulation during transurethral prostatectomy (TURP) is NOT related to A. prostate size B. height of the irrigation fluid bag C. duration of surgery D. surgical technique E. type of irrigation fluid |
E. type of irrigation fluid
➭ 20 ml/min of irrigant solution is normally absorbed (1 - 1.5 liters for the average case) ➭ Amount of fluid absorbed dependent on: - hydorstatic pressure (height of irrigation fluid bag) - venous pressure - duration of surgery / large prostate (>50g) - blood loss (implies large number of veins open) - surgical ability to preserve prostatic capsule TURP syndrome remains a significant complication of TURP. Patients are particularly at risk when * Resection time longer than 60 minutes * Resected prostatic weight heavier than 30 grams * Irrigant volume greater than 30 liters. The risk is enhanced when performed by inexperienced resectionists or residents in their early stage of training. ----------- |
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SZ11 [2003-Aug] Q111, [Mar06] [Jul06][Apr08][Oct08][Oct09][Aug10]
Lowering intra-ocular pressure by applying pressure to the globe (e.g. Honan balloon) is typically contraindicated in a patient having A. a revision corneal graft B. a revision trabeculectomy C. an extra-capsular lens extraction D. a redo vitrectomy E. repeat retinal cryotherapy |
B. a revision trabeculectomy
Flap has been created (eye is open) and pressure is likely not to be normal. All other surgeries should involve a normal eye. ----------- |
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SZ12 [2001-Apr] Q148
In patients with a single lung transplant, obliterative bronchiolitis 1. is a more common cause of death than either rejection or infection of the transplanted lung 2. is usually a complication occurring more than six months after transplantation 3. can also affect their native, non-transplanted lung 4. typically presents with a cough suggestive of a mild respiratory tract infection |
2. is usually a complication occurring more than six months after transplantation
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SZ14 [2004-Apr] Q103, [2004-Aug] Q81, [Apr07]
In the recovery room, following general anaesthesia for renal transplant surgery, your patient is found to have a serum potassium concentration of 6 mmol.l-1, despite having a normal potassium concentration pre-operatively. His oxygen saturation is 96% on approximately 40% oxygen via a Hudson mask. He is still unconscious, but breathing spontaneously at 8 breaths per minute. The most likely cause of his hyperkalaemia is A. beta-blockers which he received peri-operatively B. catabolic stress of surgery C. opioid induced narcosis causing carbon dioxide retention D. renal graft failure E. washed red blood cell transfusion, which he received intraoperatively |
C. opioid induced narcosis causing carbon dioxide retention
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SZ14b [2004-Aug] [Jul07][Apr08][Oct09][Mar10]
Following a cadaveric renal transplant under general anaesthesia, your patient's plasma K+ increases to 6.0 mmol.l-1 in recovery after being 5.0 mmol.l-1 pre and intra-operatively. This patient requires A. an intravenous infusion of CaCl2 (10 mls over 20 minutes) B. arterial blood gases to ascertain the acid/base status C. potassium exchange resins rectally D. sodium bicarbonate infusion (50- 100 mEq over 5- 10 minutes) E. urgent haemodialysis |
B. arterial blood gases to ascertain the acid/base status
only takes a few minutes and then best treatment is decided. ----------- |
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SZ14b [Aug10]
Management of rhabdomyolysis – best option? A. Haemodialysis B. Bicarbonate C. Frusemide D. IV fluids E. |
D. IV fluids
- From UTD 'Prevention and treatment of heme pigment-induced acute kidney injury (acute renal failure) Acute kidney injury can occur in patients who have rhabdomyolysis and, less commonly in patients with hemolysis. In both groups, AKI is due to the non-protein heme pigment that is released from either myglobin or haemoglobin and is toxic to the kidney. Prevention goals are two fold - correction of volume depletion if present - prevention of intratubular cast formation A. The use of dialysis to remove myoglobin, haemoglobin or uric acid to prevent the development of renal injury has not been demonstrated. Dialysis may be necessary to TREAT established AKI to control volume control, hyperkalaemia, severe academia and uraemia (i.e. would only dialyse if there was an indication) B. Bicarbonate - a forced alkaline diuresis, in which the urine pH is raised to above 6.5, may diminish the toxicity of heme. In theory, urine alkalisation prevents heme-protein precipitation with Tamm-Horsfall protein and therefore intratubular pigment cast formation. Alkalinization may also decrease the release of free iron from myoglobin and the formation of F2-isoprostanes, which may enhance renal vasoconstriction and decrease the risk for tubular precipitation of uric acid. HOWEVER there is no evidence to show that it is more effective than a saline diuresis in preventing AKI. C. Frusemide - The benefit of loop diuretics or mannitol in rhabdomyolysis is NOT established. D. IV fluids - TRUE. In addition to treating the underlying rhabdomyolysis, prevention of AKI requires early and aggressive fluid resuscitation. The goals of volume repleten are to maintain or enhance renal perfusion, thereby minimising ischemic injury and to increase the urine flow rate which will limit intratubular cast formation, wash out partially obstructing casts and increase urinary potassium excretiom. ----------- |
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SZ17 ANZCA version [2004-Apr] Q128, [2004-Aug] [Mar10][Sep11]
During surgery to repair an aneurysm of the aortic arch using circulatory arrest, the most effective method to minimise cerebral injury is A. antegrade cerebral perfusion via the carotid arteries during the arrest period B. retrograde cerebral perfusion via the internal jugular veins during the arrest period C. intravenous methyl prednisolone prior to the arrest period D. intravenous thiopentone prior to the arrest period E. systemic hypothermia to 20oC during the arrest period |
A. antegrade cerebral perfusion via the carotid arteries during the arrest period
OR E. systemic hypothermia to 20oC during the arrest period ?A>E (A must be done in conjunction with moderate hypothermia) Answer is A according to RPA course - Wiki debate. Controversial. See 2010 articles regarding which method is best? Depends on duration of surgery. Deep Hypothermic Cardiac Arrest (DHCA) only if repair is short. Selective Anterograde Cerebral Perfusion (SACP) seems to have better results? and can be used for longer (use with moderate hypothermia). From Cardiol Clin 28 (2010) 389-401: "The safety provided by SACP during a nonlimited time of arch exclusion makes it the gold standard in brain protection during arch surgery. This opinion has been strengthened by the publication of numerous clinical studies reporting excellent results with SACP associated with core moderate hypothermia (23–25C). In addition to our own experience, all those publications have reinforced our conviction that perfusing the cerebrum antegradely represents the best and safest way of preserving the complete integrity of the neurologic functions in terms of sensory-motor and cognitive faculties, as acknowledged recently by Griepp.72 This is particularly true in frail and aged patients or in patients requiring a long and difficult surgical procedure." Editorial comment of the same issue recommends SACP. ----------- |
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SZ18 ANZCA version [2004-Aug] Q147, [2005-Apr] Q76, [Mar06] [Apr07] [Sep11]
The physiological change most likely to be associated with infrarenal cross-clamping of the aorta is A. decreased coronary blood flow B. decreased renal blood flow C. increased cardiac output D. increased heart rate E. reduction in myocardial wall motion abnormalities |
B. decreased renal blood flow
“Regardless of the position of the aortic cross-clamp, RBF is decreased to 50% of normal during surgical preparation of the aorta, presumably because of direct compression or reflex spasm of the renal arteries. After release of the suprarenal cross-clamp, RBF increases above normal (reflex hyperemia), but the GFR remains depressed to a third of control for up to 2 hours.” Miller. Preload does not necessarily increase with infrarenal clamping (Miller fig 52-11). ----------- |
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SZ19 ANZCA version [2004-Aug] Q122, [2005-Apr] Q68, [Mar06] [Jul06]
The most correct statement regarding the Child-Pugh score for liver disease is that A. a high-risk score is not possible with normal aminotransferase levels B. a high-risk score is possible without encephalopathy C. a prothrombin time greater than 10 seconds above normal confers extra points to the raw score D. it has not been validated for non-shunt and non-transplant laparotomies E. it was originally developed for patients undergoing hepatic transplantation |
B. a high-risk score is possible without encephalopathy
Child-Pugh Score (up to 3 points each) 'A_ll A_lcoholics B_leed P_uke and E_xsanquinate' - Albumin - Ascites - Bilirubin - PT (INR) - Encephalopathy Points Class 1 year survival 2 year survival 5-6 A 100% 85% 7-9 B 81% 57% 10-15 C 45% 35% It was originally derived from patients undergoing portosystemic shunting for variceal hemorrhage; however, subsequent studies showed it to be useful in estimating risks for patients with liver disease undergoing hepatic and nonhepatic surgery (Garrison, 1984; Leonetti, 1984; Cryer, 1985; Mansour, 1997). ----------- |
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SZ20 ANZCA version [2004-Aug] Q100, [2005-Apr] Q84, [Apr07]
In a patient with an intra-orbital haemorrhage, following local anaesthetic injection, the adequacy of ocular perfusion is best assessed by A. angiography B. direct ophthalmoscopy C. indirect ophthalmoscopy D. intra-ocular pressure tonometry E. palpation of the globe by an experienced clinician |
B. direct ophthalmoscopy
vs C. indirect ophthalmoscopy B>C B will give you a view of the fundus to assess central artery C gives a wider field of view - Debated on wiki. B according to Cass. Anaesthesia for Eye Surgery Podcast. ANZCA 2009. ----------- |
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SZ21 ANZCA version [2004-Aug] Q144, [2005-Apr] Q80
In maxillo-facial trauma A. external soft tissue signs correlate with actual skeletal disruption B. Le Forte fractures rarely occur in combination (e.g. Le Forte 1 and 2) C. Le Forte 1 fractures should NOT be intubated nasally D. Le Forte 2 fractures require base of skull evaluation before nasal intubation E. Le Forte 3 fractures involve a fracture of the cribriform plate |
D. Le Forte 2 fractures require base of skull evaluation before nasal intubation
Miller p.2542 A Le Fort I fracture is a simple horizontal fracture of the lower part of the maxilla that produces only a mobile palate. A Le Fort II fracture, a triangular extension of a Le Fort I fracture, involves two oblique fracture lines along the malomaxillary suture to the floor of the orbit and the base of the tongue. A Le Fort III fracture is a transverse fracture above the malar bone and through the orbits. It is characterized by complete separation of the maxilla from the craniofacial skeleton, epistaxis, and a flat dish-face deformity. Tears in the dura occur in 25% of all Le Fort II and III fractures, along with leakage of cerebrospinal fluid. Orotracheal intubation is necessary with intranasal damage. Attempted passage of a nasogastric or nasotracheal tube may cause bleeding, mucosal dissection, and further damage. These tubes can enter the maxillary antrum, the orbit, the base of the skull, or the cranium. ----------- |
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SZ22 ANZCA version [2005-Apr] Q129, [Mar06] [Jul06][Apr08][Oct08]
Regarding a patient presenting for renal transplantation due to diabetic nephropathy, which of the following statements is LEAST correct? A. angiotensin-converting enzyme (ACE) inhibitors are probably best discontinued preoperatively B. dialysis is indicated if serum potassium concentration exceeds 6 mmol.1-l C. intravenous access should preferably be obtained in a forearm vein of the non-fistulous arm D. suxamethonium causes a rise in serum potassium concentration of up to 0.6 mmol.1-l E. temporomandibular joint rigidity may be present |
C. intravenous access should preferably be obtained in a forearm vein of the non-fistulous arm
- See long winded wiki debate - ultimately C. may need vein later if graft fails! ----------- |
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SZ23 [Mar06]
Regarding decontamination of anaesthetic equipment A. alcohol is an effective sporicidal agent B. disinfection is sporicidal C. phenol is an effective sporicidal agent D. sterilisation with ethylene oxide requires 5 to 12 hours to be effective E. sterilisation with glutaraldehyde requires 5 to 8 hours to be effective |
D. sterilisation with ethylene oxide requires 5 to 12 hours to be effective
- From wiki: A. alcohol is sporicidal - false: " A few disinfectants have sporicidal activity with prolonged exposure and are called high-level disinfectants. It is this level of disinfection that is commonly used for semi-critical anaesthetic and respiratory therapy equipment. High-level disinfectants include gluteraldehyde, stabilized hydrogen peroxide, peracetic acid, chlorine and chlorine-releasing compounds. Low-level disinfectants will kill most vegetative bacteria and some viruses and fungi. Examples include alcohols, sodium hypochlorite and iodophore solutions." (Continuing Education in Anaesthesia, Critical Care & Pain 2004 4(4):103-106) B. disinfection is sporicidal - false: See above C. phenol is sporicidal - false: See Table 2 D. sterilisation with ethylene oxide requires 5-12 hours to work - true: "In the US, ethylene oxide is used commonly for the sterilization of heat- and moisture-sensitive devices. It is a colourless gas and very flammable; risks of fire are reduced by dilution with inert gases such as carbon dioxide or hydroflurocarbons. Microbiocidal activity is thought to be the result of alkylation of protein, DNA and RNA. Temperatures of 29–65°C are employed and cycles are 5–12 h." E. sterilisation with glutaraldehyde requires 5-8 exposure hours to work - false: "Immersion in gluteraldehyde 2% is a form of sterilization and is used for optical instruments such as cytoscopes or bronchoscopes as it is non-corrosive and has no deleterious effects on lens cement. Immersion must be >10 h; less time will result in disinfection, not sterilization." ~~ ----------- Decontamination of anaesthetic equipment Continuing Education in Anaesthesia, Critical Care & Pain 2004 4(4):103-106 Bioburden: The population of viable infectious agents contaminating a medical device Cleaning: The physical removal of foreign material including infectious agents and organic matter. This does not necessarily destroy infectious agents Decontamination: A process that removes or destroys contamination so that contaminants cannot reach a susceptible site in sufficient quantities to initiate an infection or any other harmful response. It always involves cleaning followed by disinfection and/or sterilization Disinfection: A process that eliminates many or all pathogenic organisms except bacterial spores. Chemicals used to disinfect inanimate objects are called disinfectants. Chemicals used to disinfect body surfaces are termed antiseptics High-level disinfectant: A chemical agent that can kill bacteria, viruses and spores. It is only sporicidal under certain conditions Sterilization: A process that renders an object completely free of all viable infectious agents by eliminating all forms of microbial life |
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SZ24 [2004-Aug] Q101
Of the options below, the best anaesthetic method for ophthalmic examination under anaesthesia in a co-operative mentally retarded adult (without aspiration risk) is intravenous induction and A. intermittent positive pressure ventilation via endotracheal tube B. intermittent positive pressure ventilation via laryngeal mask airway C. spontaneous ventilation with inhalational agents via facemask D. spontaneous ventilation with inhalational agents via laryngeal mask airway E. ketamine and spontaneous ventilation via cut-down Hudson mask |
D. spontaneous ventilation with inhalational agents via laryngeal mask airway
~~ ----------- OHA p.656 ETT or LMA? Unless contraindicated, the LMA is ideal. It obviates laryngoscopy with the consequent adverse effects on IOP. It produces minimal stimulation once in situ and permits lighter anaesthesia. The quality of emergence is also superior (see below). IPPV or SV? For minor and extraoccular surgery spontaneous ventilation is acceptable. Controlled ventilation has a number of advantages in intraocular and more major surgery. It allows more precise control of CO2 (reducing IOP and desensitizing the oculomedullary reflex) and permits benefits of a balanced technique: - Ventilating via an LMA is usually uneventful. Avoid high airway pressures (>15 cmH2O, with the risk of gastric insuflation) if possible by adjusting the tidal volume and using a more symmetrical I:E ratio (i.e. 1:1.5 as opposed to 1:3). - Always monitor the CO2 waveform. Any change in the waveform usually heralds a change in ventilation before it is clinically apparent (malpositioned LMA, inadequate muscle relaxation). - Use a nerve stimulator routinely. Coughing and gagging are less well tolerated by ophthalmic surgeons than by their orthopaedic colleagues! |
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SZ25 [Apr07]
A patient comes back to theatre for control of bleeding post tonsillectomy. The most important aspect of his management is A. avoidance of premedication B. avoidance of volatile anaesthesia C. duplicate suctioning device and ETT's available D. E. RSI |
C. duplicate suctioning device and ETT's available
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SZ26 [Apr07]
A 40 pack year smoker complains of progressive dyspnoea. He has had stridor for the last 3 weeks, worsening in the last week. He is awoken at night with breathlessness. In the emergency department he has moderate stridor is sitting upright and has saturations of 95%. Your next step in management is: A. Awake fibreoptic B. CT neck C. Nasendoscopy with topical anaesthesia D. Assessment after gaseous anaesthetic induction E. Tracheostomy under local anaesthesia |
C. Nasendoscopy with topical anaesthesia
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SZ27 ANZCA version [2004-Mar] Q100
The following measures have been shown to reduce intraoperative blood loss in some surgical situations, EXCEPT A. arterial hypotension (MAP = 50 mmHg) B. controlled ventilation C. hypothermia (less than 34°C) D. maintenance of a low central venous pressure E. regional anaesthesia |
C. hypothermia (less than 34 degrees C)
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