2010.2 Flashcards
TMP-Jul10-001 Pre-eclamptic woman, BP 170/110, headache, proteinuria 1.2g. Which of the following NOT to use for control of her hypertension:
A. Magnesium B. SNP C. GTN D. Hydralazine E. Metoprolol
A. Magnesium
(Mg used for seizure prophylaxis, not for control of BP)
ANZCA says that SNP should be used only as “last resort”, and specifically states “MgSO4 does not reverse or prevent the progression of the disease, nor does it significantly lower BP and it is not recommended as an antihypertensive agent”
Medscape:
In a severe hypertensive emergency, when the above-mentioned medications (hydralazine, labetolol, nifedipine) have failed to lower BP, sodium nitroprusside may be given. Nitroprusside results in the release of nitric oxide, which in turn causes significant vasodilation. Preload and afterload are then greatly decreased. The onset of action is rapid, and severe rebound hypertension may result. Cyanide poisoning may occur subsequent to its use in the fetus. Therefore, sodium nitroprusside should be reserved for use in postpartum care or for administration just before the delivery of the fetus.
The basic principles of airway, breathing, and circulation (ABC) should always be followed as a general principle of seizure management.
Magnesium sulfate is the first-line treatment for the prevention of primary and recurrent eclamptic seizures. For eclamptic seizures that are refractory to magnesium sulfate, lorazepam and phenytoin may be used as second-line agents.
Hypertens Pregnancy. 2004;23(1):37-46.
The effect of glyceryl trinitrate on hypertension in women with severe preeclampsia, HELLP syndrome, and eclampsia.
In women with severe preeclampsia, eclampsia, and HELLP syndrome, infusion of GTN can be used as an alternative agent to well-known drugs and causes no significant adverse effect to the mother and fetus.
TMP-Jul10-002 Male with a Haemoglobin of 8 g/L and reticulocyte count 10%. Possible diagnosis:
A. Untreated pernicious anaemia B. Aplastic anaemia C. Acute leukaemia D. Anaemia of chronic disease E. Hereditary spherocytosis
E. Hereditary spherocytosis
Raised reticulocyte - usually indicates haemolysis
Normal reticulocyte count is 0.5-1.5%
The reticulocyte count is a good indicator of bone marrow activity.
Abnormally low numbers of retics can be attributed to chemo, aplastic anaemia, pernicious anaemia, bone marrow malignancies, decreased EPO, deficiencies (B12, folate, iron), anaemia of chronic disease….
When there is increased production of red cells to overcome loss (eg haemolytic anaemia), reticulocyte count is high.
TMP-Jul10-003 Commonest organism causing meningitis post spinal:
A. Staph epidermidis B. Staph salivarius C. Staph aureus D. Strep pneumoniae E. ?
B. Staph salivarius
IATROGENIC MENINGITIS AFTER SPINAL ANESTHESIA Acta Medica Iranica 2008; 46(5): 434-436.
Various strains of viridans streptococcus (a mouth commensal) are the dominant causative organism in post dural puncture meningitis (PDPM); other causal organisms found in PDPM include Staphylococcus aureus, Pseudomonas aeruginosa, and Enterococcus faecalis. However, in 36% of patients, no organism was isolated or reported.
Bacterial Meningitis After Intrapartum Spinal Anesthesia — New York and Ohio, 2008–2009 Centres for Disease Control and Prevention
Potential sources of bacterial introduction into the intrathecal space during spinal procedures include intrinsic or extrinsic contamination of needles, syringes, or injected medications; inadequately decontaminated patient skin; inadequately cleaned health-care provider hands; a contaminated sterile field; and droplet transmission from the health-care provider’s upper airway. S. salivarius and other viridans group streptococci, which are normal mouth flora, are the most commonly identified etiologies of meningitis after spinal procedures, accounting for 49% and 60% of cases in two literature reviews (2,6). Droplet transmission of oral flora has been suggested as the most likely route of transmission in reports of clusters associated with a single health-care provider (7,8).
In epidural abscess, the most common causative organism is Staph aureus.
TMP-Jul10-004 Exponential decline / definition of time constant (with various options)
A. time for exponential process to reach log(e) of its initial value
B. Time until exponential process reaches zero
C. Time to reach 37% of initial value
D. Time to reach half if its initial value
E. 69% of half life
C. Time to reach 37% of initial value
From BB:
Time constant is the time taken for the concentration/amount of something to fall to 1/e of the initial concentration/amount. The number “e” equals 2.718281828. 1/e = 0.368. Therefore the time constant is the time it takes for the concentration/amount to fall to 36.8% of the initial value (approx 37%). Clearly the time constant is longer than the half life, and there is a formula relating the two: half life = log(e)2 x time constant; thus half life = 0.693 x time constant.
TMP-Jul10-005 (This is a very old repeat) Relative humidity: air fully saturated at 20 degrees. What is the relative humidity at 37 degrees ?
A. 20 B. 30 C. 40 D. 50 E. 60%
C. 40%
From BB: “1m3 of air at 20˚C, 100% saturated, contains about 17g of water. If it is warmed to 37˚C, the mass of water vapour (or absolute humidity) is still the same but the relative humidity is only 39%. At 37˚C, 1m3 of air contains 44g of water vapour when fully saturated and the ratio of 17 to 44 gives a value of 39%.”
TMP-Jul10-006 A 50 year old man with multiple fractures. The BEST parameter to monitor volume resuscitation is:
A. Heart rate B. LVEDV C. PCWP D. RVEDV E. Changes in R atrial pressure during inspiration
E. Changes in R. atrial pressure during inspiration
From Stanford uni echo site:
Static indices
Central venous pressure (CVP), left ventricular end-diastolic area, E/Ea and wedge pressure are indicators of ventricular filling, but do not reliably predict volume responsiveness.
Ideally, the volume status is a “functional assessment”: to induce a change in cardiac preload and observe the effects on cardiac output and arterial pressure.
How to assess the hemodynamic response to volume challenge?
The objective is to distinguish responders (=patients who will benefit from volume expansion) from non-responders (=patients for whom volume expansion may be deleterious).
Clinical parameters can be used: blood pressure, heart rate, urine output… but are not sensitive nor specific.
1. If the ventricles are still pre-load dependant (steep portion of Frank-Starling curve), increase in right ventricle filling will lead to increased right ventricle output, which will increase the left ventricle filling and output. Thus the cardiac output will follow the variations in venous return, leading to respiratory variations of stroke volume.
It has been validated (5) that respiratory variations > 20% of stroke volume predict positive hemodynamic response to volume expansion. VTI or maximum velocity of LVOT flow can be used as surrogates of stroke volume.
2. Respiratory variations of IVC diameter will be observed only in patients in whom the right atrial pressure is not high, indicating right ventricle pre-load dependence. IVC diameter respiratory variations can therefore predict the hemodynamic response to volume challenge (6-7):
▪ respiratory variations of IVC diameter are greater in patients who will respond to fluid expansion
▪ after fluid infusion, respiratory variations of IVC diameter decreased significantly in these patients
▪ small IVC (
TMP-Jul10-007 Anaphylaxis to rocuronium. Which is most likely to cause coss-reactivity ?
A. Vecuronium B. Pancuronium C. Atracurium D. Cisatracurium E. None of the above -cross reactivity too variable to predict
A. Vecuronium
(from BJA paper 2013):
Anaphylaxis to roc –> cross reactivity to sux > vec > atrac > panc > cisatrac
Suspected anaphylactic reactions associated with anaesthesia. Anaesthesia 2009
Cross-sensitivity between different NMBAs is relatively common, probably because they share a quaternary ammonium epitope. If anaphylaxis to an NMBA is suspected, the patient should undergo skin prick testing with all the NMBAs in current use. If a patient demonstrates a positive skin prick test (SPT) to an NMBA, the patient should be warned against future exposure to all NMBAs if possible. If it is mandatory to use an NMBA during anaesthesia in the future, it would seem appropriate to permit the use of an NMBA which has a negative skin test, accepting that a negative skin test does not guarantee that anaphylaxis will not occur.
Allergy 2007; 62: 471-487 Review Article: Anaphylaxis during anaesthesia: diagnostic approach “Cross Reactivity between NMBA is said to be common because of ubiquitous ammonium groups in these drugs. The estimated prevalence of cross-reactivity between NMBA is about 65% by skin tests and 80% by radioimmuno assay inhibition tests. While some pairings are common, the patterns of cross-reactivity vary considerably between patients.”
TMP-Jul10-008 Hypotension post propofol induction in elderly patient. More pronounced / profound than in younger patient. Reason ?
A. Concentric LVH associated with ageing and therefore preload dependent
B. Because of increased lean body mass
C. Decreased cardiac output with ageing
D. Increased sensitivity to all anaesthetic agents, thus relative overdose is common
E. Decreased liver blood flow with ageing, decrease drug clearance and increased drug concentration
A. Concentric LVH associated with ageing and therefore preload dependent.
?D also correct (increased sensitivity to all anaesthetic agents)
Geriatric Anesthesiology, Rooke et al (google books)
“The brain becomes more sensitive to propofol with increasing age; Schnider et al reported that geriatric patients were approximately 30% more sensitive to pharmacodynamic effects of propofol than younger subjects, as measured by EEG changes.
The degree of hypotension is increased…in the geriatric patient, by several mechanisms. First propofol impairs the arterial baroreceptor reflex to hypotension, which is already decreased in the geriatric patient. Second, the geriatric patient is more likely to have ventricular dysfunction. A decrease in preload in these patients may result in a significant decrease in cardiac output…
TMP-Jul10-009 Predictive factors for mortality in elderly patient (except):
A. Aortic stenosis B. Diabetes mellitus C. Elevated Creatinine D. Cognitive dysfunction E. Type of surgery
???
Lots of references… all seem to have been shown to be associated with increased mortality by various people.
Am J Med. 2004 Jan 1;116(1):8-13.
Aortic stenosis: an underestimated risk factor for perioperative complications in patients undergoing noncardiac surgery
Aortic stenosis is a risk factor for perioperative mortality and nonfatal myocardial infarction, and the severity of aortic stenosis is highly predictive of these complications.
Minimizing perioperative adverse events in the elderly, BJA 2001
Predictive factors:
The function capacity of organs reduces with ageing, resulting in decreased reserve and ability to endure stress. Advanced age is, therefore, a significant risk factor for increased mortality. Co‐existing disease further depresses organ function and/or reserve, exacerbating risk. For example, pre‐existing hypertension, diabetes mellitus, or renal failure contributes to a higher incidence of perioperative myocardial infarction (MI) (5.1%), cardiac death (5.7%) or ischaemia (12–17.7%). Additional risk factors in the elderly include the need for emergency surgery, major surgical procedures, ASA physical status III or IV, and poor nutritional status.
The elderly surgical patient 2008
In 1999, Lee and colleagues developed a simplified index known as the Revised Cardiac Risk Index (RCRI), which included six variables that had been found to be independent predictors of cardiac complications. In the RCRI, one point is given for each of the following cardiac risk factors: (1) a history of CHF, (2) a history of ischemic heart disease, (3) a history of cerebrovascular disease, (4) preoperative treatment with insulin, (5) a preoperative serum creatinine level higher than 2.0 mg/dl, and (6) a high-risk surgical procedure.
Preoperative cognitive dysfunction has been associated with increased postoperative complications and worse survival in elderly surgical patients. Such dysfunction may take the form of either dementia or delirium. Dementia is a chronic baseline impairment of cognitive function. Demented patients are known to experience higher postoperative mortality than patients with intact cognitive function. Delirium is an acute confusional state associated with multiple possible causes. The incidence of postoperative delirium in older patients ranges from 20% to 60%. This state is associated with a prolonged hospital stay, functional decline, and increased mortality. Risk factors for the development of postoperative delirium include preexisting dementia, visual impairment, alcohol consumption, infection, narcotic use, and polypharmacy.
Complications and mortality in older surgical patients in Aus and NZ (the REASON study), Anaesthesia, 2010 (K Leslie et al)
Pre-operative factors associated with mortality included: increasing age (80-89 years: OR 2.1 (95% CI 1.6-2.8), p
TMP-Jul10-010 The best clinical indicator of SEVERE AS
A. Presence of thrill B. Mean Gradient 30mmHg C. Area 1.2 cm2 D. Slow rising pulse and ESM radiating to carotids E. Shortness of breath
A. Presence of a thrill
TMP-Jul10-011 Elderly patient. Indications for pre Femoro-Popliteal Bypass coronary angiogram include all EXCEPT:
A. Severe heart failure B. Suspicion of L main disease C. Symptomatic tachyarrhythmia D. Unstable angina E. Stable angina with positive thallium
? C. Symptomatic tachyarrhythmia
AHA/ACC 1999
Recommendations for Coronary Angiography in Perioperative Evaluation Before (or After) Noncardiac Surgery:
Class I: Patients with suspected or known CAD
- Evidence for high risk of adverse outcome based on noninvasive test results. (Level of Evidence: C)
- Angina unresponsive to adequate medical therapy. (Level of Evidence: C)
- Unstable angina, particularly when facing intermediate or high-risk noncardiac surgery. (Level of Evidence: C)
- Equivocal noninvasive test result in a high-clinical-risk patient undergoing high-risk surgery. (Level of Evidence: C)
Class IIa
- Multiple intermediate-clinical-risk markers and planned vascular surgery. (Level of Evidence: B)
- Ischemia on noninvasive testing but without high-risk criteria. (Level of Evidence: B)
- Equivocal noninvasive test result in intermediate-clinical-risk patient undergoing high-risk noncardiac surgery. (Level of Evidence: C)
- Urgent noncardiac surgery while convalescing from acute MI. (Level of Evidence: C)
Class IIb
- Perioperative MI. (Level of Evidence: B)
- Medically stabilized class III or IV angina and planned low-risk or minor surgery. (Level of Evidence: C)
TMP-Jul10-012 How do you minimise risk of intravenous cannulation with epidural insertion?
A. Injection saline through epidural needle before catheter insertion B. Lie patient lateral C. Do CSE D. Thread catheter slowly E.
A. Injection of saline through epidural needle before catheter insertion (OR 0.53)
B. Lie patient lateral (OR 0.49)
(Systematic review, Anesth Analg 2009)
TMP-Jul10-013 Timing of peak respiratory depression post intrathecal 300 mcg morphine:
A. 18 hours
B. 3.5-7.5 h
ANZCA Acute Pain: Scientific Evidence 3rd ed:
“Respiratory depression occurs in up to 1.2% to 7.6% of patients (Meylan et al, 2009 Level I) given intrathecal morphine. When measured in opioid-naive volunteers, respiratory depression peaked at 3.5 to 7.5 hours following intrathecal morphine at 200 to 600 mcg doses (Bailey et al, 1993 Level IV). Volunteers given 600 mcg had significant depression of the ventilatory response to carbon dioxide up to 19.5 hours later.
TMP-Jul10-014 Patient with aortic dissection. Blood pressure 150/90. Best drug to control BP:
A. Captopril B. Esmolol C. GTN D. Hydralazine E. SNP
B. Esmolol
(reduces force of LV contraction)
If beta-blocker alone not sufficient to control BP, add vasodilator
TMP-Jul10-015 Type of dissection – which is classically for NON-operative management:
A. DeBakey Type I B. DeBakey Type II C. Stanford A D. Stanford B E. Stanford C
C. Stanford A
Stanford classification
Type A — dissection extends to arch/ascending aorta –> needs operative repair
Type B — dissection of the descending aorta only (distal to L. subclavian artery) –> medical management with BP control
De Bakey classification
Type 1 — dissection of the entire aorta
Type 2 — dissection of the ascending aorta
Type 3 — dissection of the descending aorta
TMP-Jul10-016 TURP – patient under spinal. Confused. ABG: Na+ 117 / normal gas exchange. Treatment ?
A. 10 ml 20% Saline as fast push IV B. 3% NS 100 ml/h C. Normal saline 200 ml/h D. Frusemide 40 mg IV E. Fluid restrict 500 ml/day
B. 3% saline 100 mL/h
1.2-2.4ml/kg/hr of 3% saline until symptomatic improvement (this rate should increase serum Na+ by 1-2 mmol/h)
TMP-Jul10-017 Male undergoing trans-sphenoidal surgery. Now Na+ 155mmol/l and thirsty with polydipsia. Treatment:
A. Desmopressin (DDAVP) B. Fluid restrict C. Aldosterone D. E.
A. DDAVP
TMP-Jul10-018 The STRONGEST stimulus for ADH secretion:
A. High serum osmolality B. Low serum osmolality C. Hypovolaemia D. High serum Na E.
C. Hypovolaemia
From BB:
Osmoreceptor control is very sensitive, responding to 1-2% changes in plasma osmolality.
If hypovolaemia is present, this will ‘over-ride’ osmoreceptor control. Thus it is commonly said that volume is maintained at the expense of osmolality, or equivalently, that hypovolaemia will result in an increase in ADH level despite the inhibitory effect of hypo-osmolality.
The actual plasma levels that occur with hypovalaemia are much higher that those occurring with hyperosmolality, so volume control (of ADH secretion) is less sensitive, but much more powerful.
TMP-Jul10-019 Stellate ganglion block. Needle entry next to SCM muscle at C6. Which direction to advance needle ?
A. C3 B. C4 C. C5 D. C6 E. C7
D. C6
The patient is placed in the supine position with the neck slightly extended, the head rotated slightly to the side opposite the block, and the jaw open. The point of needle puncture is located between the trachea and the carotid sheath at the level of the cricoid cartilage and Chassaignac’s tubercle. Although the ganglion lies at the level of the C7 vertebral body, the needle is inserted at the level of C6 to avoid the piercing the pleura. Cutaneous anaesthesia is obtained with a skin wheal of local anaesthetic.
The sternocleidomastoid and carotid artery are retracted laterally as the index and middle fingers palpate Chassaignac’s tubercle. The skin and subcutaneous tissue are pressed firmly onto the tubercle to reduce the distance between the skin surface and bone, and in an attempt to push the dome of the lung out of the path of the needle. When properly performed, this manoeuvre is uncomfortable for the patient.
The needle is directed onto the tubercle, and then redirected medially and inferiorly toward the body of C6. After the body is contacted, the needle is withdrawn 1-2 mm. This brings the needle out of the belly of the longus colli muscle, which sits posterior to the ganglion and runs along the anterolateral surface of the cervical vertebral bodies. The needle is then held immobile.
Needle position is confirmed by fluoroscopy. Spread of radiocontrast is confirmed by both anteroposterior and lateral views. Failure of the solution to spread cephalad and caudad between tissue planes suggests intramuscular injection into the longus colli muscle. Immediate dissipation of the solution indicates intravascular placement of the needle orifice.
TMP-Jul10-020 20. Thermoneutral zone in 1 month old infant ?
A. 26 – 28 degrees Celcius B. 28 – 30 degrees Celcius C. 30 – 32 degrees Celcius D. 32 – 34 degrees Celcius E. 34-46 degrees celcius
C. 30-32C
(Term neonate has TNZ of 32-34C; TNZ is higher from premature neonates)
Thermoneutral zone = ambient temperature where minimal O2 consumption is required to maintain core temperature
Paediatric Surgery, diagnosis and management, 2009:
- Infants weighing 2 – 3kg have a TNZ of 31-34C at birth and 29-31C at 12 days.
Public Health Nutrition: 8(7A), 953–967
- In the first 24 hours after birth, this temperature is 34–36C for the naked infant and falls to 30–32C by 7–10 days of age.
TMP-Jul10-021 A 60 year old man describes orthopnoea. On examination: pansystolic murmur (at LSE)/ displaced apex beat. Likely diagnosis ?
A. Mitral regurgitation B. ? C. D. E.
A. Mitral regurgitation
TMP-Jul10-022 A 4 year old child with VSD (repaired when 2 years old) for dental surgery. What antibiotic prophylaxis do the guidelines recommend?
A. Amoxycillyn orally B. Amoxycillin IV C. Cephazolin IV D. Amoxycillin / gentamicin E. No antibiotics required
E. No antibiotics required
TMP-Jul10-023 A 4 year old child with Arthrogrophysis multiplex congenita for dental surgery. Jaw rigidity post induction. Likely cause?
A. Temporomandibular joint involvement/ TMJ rigidity
B. Inadequate depth of anaesthesia
C. Inadequate muscle relaxation/ inadequate sux
D. Masseter spasm
E. ?
A. TMJ involvement/rigidity
Arthrogryposis Multiplex Congenita is a rare congenital disorder that causes multiple joint contractures and can be associated with muscle weakness and fibrosis. It is a non-progressive disease. Anaesthetic issues include difficult IV access, airway and association with anterior horn cell disease. Although an association with MH has been suggested, this has not been confirmed…
Patients with arthrogryposis have micrognathia, a high arched palate, and a short and rigid neck making tracheal intubation difficult and at times impossible. The primary concern to the anesthesiologist is the potential for airway involvement thereby making direct laryngoscopy and endotracheal intubation difficult.
Direct laryngoscopy and intubation become more difficult as the patient ages because craniofacial involvement often progresses with growth. Alternatives to direct laryngoscopy and tracheal intubation, such as the use of the laryngeal mask airway, with or without the use of a tube exchanger, or fiberoptics, have been used successfully in this disorder. In such difficult airway scenario we decided to avoid intubation and maintained her on spontaneous ventilation. We kept difficult intubation cart ready in case required to secure airway in emergency.
The extensive contractures, tense skin, and minimal muscle mass and subcutaneous tissue pose challenges for intraoperative positioning and intravenous access. Children with arthrogryposis may have altered responses to neuromuscular relaxants and are akin to other patients with anterior horn cell diseases.
Response to nondepolarizing relaxants has been reported to be extremely variable, the use of short-acting nondepolarizing agents in association with careful monitoring of neuromuscular function has been advocated in these patients
TMP-Jul10-024
A 78 year old man with past history of a difficult intubation presents for arm surgery. Supraclavicular block with 25 mls 0.5% bupivacaine. Shortly after begins convulsing. INITIAL management?
A. Midazolam 5mg B. Intralipid 20% 1.5 ml/kg C. Thiopentone 150mg D. Suxamethonium 50mg E. Propofol 50mg
A. Midazolam 5 mg
ASRA Practice Advisory on Local Anesthetic Systemic Toxicity (Regional Anesthesia & Pain Medicine 2010)
• If seizures occur, they should be rapidly controlled to prevent injury to the patient and acidosis. The Panel recommends that benzodiazepines are the ideal drugs to treat seizures because they have limited potential for cardiac depression
(benzos also less likely to cause apnoea than propofol or thiopentone)
TMP-Jul10-025
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
A. Able to achieve lobar isolation
Curr Opin Anaesthesiol 2007
Bronchial Blockers
Advantages
o Easy recognition of anatomy if the tip of a single lumen tube is above carina
o Best device for pt with difficult airway
o No cuff damage during intubation
o No need to replace ETT if post-op ventilation required
o Selective lobar isolation is possible
Disadvantages
o Small channel for suctioning
o Conversion from 1- to 2- then to 1-lung ventilation (problematic for novice)
o High maintenance device (dislodgement or seal loss during surgery)
Double-Lumen ETTs
Advantages
o Large lumen facilitates suctioning
o Best device for absolute lung separation
o Conversion from 2- to 1-lung ventilation easy and reliable
Disadvantages o Difficulty selecting proper size o Difficult to place during laryngoscopy o Damage to tracheal cuff o Major tracheo-bronchial injuries
TMP-Jul10-026
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
C. 1.7
ppoFEV1 = pre-op FEV1 x (1 - proportion of functional lung tissue removed).
Removing RLL (= 12/42 of total lung)
ppoFEV1 = 2.4 x 30/42, = 1.7
Patients with a ppoFEV1 greater than 40% are at low risk for postresection respiratory complications. The risk of major respiratory complications is increased in the subgroup with a ppoFEV1 less than 40% (although not all patients in this subgroup develop respiratory complications), and patients with a ppoFEV1 less than 30% are at high risk.
TMP-Jul10-027
Post accidental dural puncture with epidural needle. Headache. Which does NOT fit?
A. Epidural blood patch 30-50% effective
B. Unlikely to be related to epidural if purely occipital headache
C. Caffeine mildly effective in reducing headache
D. Subdural haematoma can rarely occur with PDPH
E. (? something about photophobia)
B. Unlikely to be related to epidural if purely occipital headache (false - the headache does not occur in any specific distribution within the cranium)
C. Caffeine mildly effective (false - inconclusive evidence; although at the time of this paper it was believed to be mildly effective, so answer is probably B)
Accidental dural puncture and postdural puncture headache: best practice management (Paech)
• The most effective treatment is epidural blood patch, which completely relieves 90% of patients with post-spinal PDPH and 35-45% of obstetric patients with PDPH after accidental dural puncture
TMP-Jul10-028
Cell saver. Which does NOT get filtered?
A. Foetal cells B. Free Hb C. Platelets D. Clotting factors E. Microaggregates of leukocytes
A. Fetal cells
Cell salvage as part of a blood conservation strategy in anaesthesia (BJA 2010)
• There are three phases involved in cell salvage - collection, washing, and re-infusion. Collection of red blood cells (RBCs) from the operative field requires the use of a dedicated double-lumen suction device. One lumen suctions blood from the operative field and the other lumen adds a predetermined volume of heparinized saline to the salvaged blood. The anticoagulated blood is then passed through a filter and collected in a reservoir. Separation of the components is achieved by centrifugation. The RBCs are then washed and filtered across a semi-permeable membrane, which removes free haemoglobin, plasma, platelets, white blood cells, and heparin. The salvaged RBCs are then re-suspended in normal saline with a resultant haematocrit of 50-80%. The salvaged RBCs may be transfused immediately or within 6 h
• Processing of salvaged blood removes platelets and coagulation factors which can result in a coagulopathy
• It has been demonstrated that cell savers used in combination with a leucocyte depletion filter (LDF) can significantly reduce the levels of amniotic fluid, but not fetal RBCs, in salvaged blood. Cell savers are unable to differentiate fetal from maternal RBCs. The presence of fetal RBCs in the salvaged blood for re-infusion increases the risk of maternal alloimmunization if there is any incompatibility between maternal and fetal antigens. The risk of alloimmunization is unlikely to be greater than that incurred in a normal vaginal delivery
TMP-Jul10-029
You are on a humanitarian aid mission in the developing world. Drawover vaporiser apparatus described being used. Given 400 mm tubing, OMV (Oxford Miniature Vaporiser) or diamedica vaporiser, 200mm tubing attached to self-inflating bag. Which other ONE piece of equipment is ESSENTIAL to make this system functional?
A. Halothane B. In-line Waters' Canister C. Non-rebreathing valve D. Oxygen source E. Ventilator
C. Non-rebreathing valve
Some source from the internet…
The most simple form of modern drawover system consists of two reservoir tubes, a vaporizer and a non-rebreathing valve.
Oxygen not essential - can use air from atmosphere.
Halothane not essential - can use any agent.
The in-line Waters’ canister is a type of CO2 absorbent.
TMP-Jul10-030
Regarding post craniotomy pain:
A. Local infiltration proven to reduce long-term pain
B. Local infiltration more painful than discrete nerve blocks
C. Local infiltration more efficacious than discrete nerve blocks
D. Local infiltration more efficacious than opioid analgesia
E. Local infiltration more efficacious with clonidine included
B. Local infiltration more painful than discrete nerve blocks
APMSE - 3rd ed:
• A comparison between scalp nerve block and morphine showed no relevant differences in any analgesic parameters. Scalp infiltration was also no more effective that IV fentanyl
• A comparison between SC local anaesthetic infiltration and occipital/supraorbital nerve block showed no difference between groups in the postoperative period, but nerve blocks were less painful than infiltration analgesia
APMSE 4th edition doesn’t mention anything about reduction in long-term pain (although the 3rd edition did conclude that LA infiltration reduces the incidence of chronic pain), pain on injection or relative effiacy of LA compared to opioids (just says LA is opioid sparing)
APMSE - 4th ed:
Local anaesthetic scalp block
A meta-analysis found that regional scalp block improved pain scores up to 12 h postoperatively and reduced opioid requirements until 24 h postoperatively against placebo block (Guilfoyle 2013 Level I [PRISMA], 7 studies, n=325). An RCT performed after this meta- analysis confirmed not only better analgesia after aneurysm clipping but also improved outcome (reduced PCA consumption, requirement for a postoperative antihypertensive agent and PONV incidence) with scalp block (0.75% levobupivacaine compared to placebo) (Hwang 2015 Level II, n=52, JS 5). Scalp blocks have also been used in children following craniosynostosis repair (Pardey Bracho 2014 Level IV).
Clonidine did not improve analgesia after supratentorial craniotomy (APM).
Clonidine improves duration of analgesia and anaesthesia when used as an adjunct to local anaesthetics for peribulbar, peripheral nerve and plexus blocks (APM).
Key messages (4th ed):
1. Local anaesthetic infiltration of the scalp provides early analgesia after craniotomy (S) (Level I [PRISMA]).
2. Morphine is more effective than codeine and tramadol for pain relief after craniotomy (U) (Level II).
3. Craniotomy leads to significant pain in the early postoperative period (U) (Level IV), which is however not as severe as pain from other surgical interventions (U) (Level III-2).
4. Craniotomy can lead to significant chronic headache (U) (Level IV).
The following tick box represents conclusions based on clinical experience and expert
opinion.
Acute pain following craniotomy is underestimated and often poorly treated (N).
TMP-Jul10-031
A 60 year old female is undergoing hysterectomy. Gabapentin reduces postoperative:
A. Nausea B. Vomiting C. Sedation D. Pruritus E. Constipation
A. Nausea
After hysterectomy and spinal surgery specifically, gabapentin improved pain relief and was opioid-sparing, nausea was less in patients after hysterectomy, and there was no difference in sedation (APM)
Perioperative gabapentinoids (gabapentin/ pregabalin) reduce postoperative pain and opioid requirements and reduce the incidence of vomiting, pruritus and urinary retention, but increase the risk of sedation (APM)
TMP-Jul10-032
Burns dressings. The following is proven to be of analgesic benefit:
A. Morphine gel B. Biosynthetic dressings C. Dexmedetomidine D. Lignocaine IV E. Cognitive/Distraction technique
B. Biosynthetic dressings
APMSE 3rd ed:
The use of biosynthetic dressings is associated with a decrease in time to healing and a reduction in pain during burn dressings changes (Level I evidence)
Topical analgesic techniques, such as lignocaine or morphine-infused silver sulfadiazine cream may be effective, however a topical gel dressing containing morphine was no more effective than other gel dressing in reducing burn injury pain in the emergency department
IV Sedation, as an adjunct to analgesia, can improve pain relief. Dexmedetomidine may be effective for sedation in the intensive care unit for paediatric burn patients but further trials are required
Nitrous oxide (N2O), ketamine and IV lignocaine infusions have also been used to provide analgesia for burn procedures however a Cochrane review reported that more trials were required to determine the efficacy of lignocaine (APM)
Augmented reality techniques, virtual reality or distraction techniques (Level III evidence) reduce pain during burn dressings (APM)
TMP-Jul10-033
Subtenon’s block. What is the worst position to insert block?
A. Inferonasal B. Inferotemporal C. Superonasal D. Supertemporal E. Medial canthal
C. Superonasal
There is individual variation in the disposition of blood vessels, but they congregate in the apex of the orbit. There is a view that the inferotemporal and medial parts of the orbit are relatively poorly supplied with blood vessels, whereas the superonasal region is relatively vascular (CEACCP 2005)
TMP-Jul10-034
Liposuction. Infiltration of lignocaine with 1:200,000 adrenaline. Peak plasma concentration of lignocaine occurs at:
A. 1 hour B. 3 hours C. 18 hours D. 24 hours E. 30 mins
C. 18 hours
May peak more than 8 to 12 hours after infusion (Miller).
The peak serum levels of lidocaine occur 12 to 14 hours after injection (with 1:100,000 adrenaline) (Barash).
Infusion of lidocaine, by using the tumescent formula of 0.1% lidocaine with 1:1,000,000 epinephrine, into the subcutaneous tissues of a concentration of 35 mg/kg was safe. The maximum plasma level that was reached at 11-15 hours postoperatively was 0.8-2.7 mcg/mL, well below the toxic level of 5 mcg/mL (eMedicine).
TMP-Jul10-035
Child-Pugh score. Components?
A. Bilirubin / albumin / INR (yes INR, not PT), ascites, encephalopathy
B. Various other options including AST/ALT, GGT, PT
C. ?
D. ?
E. ?
A. Bilirubin, albumin, INR, ascites, encephalopathy
TMP-Jul10-036
Which is NOT a disadvantage of drawover vaporiser versus plenum vaporiser:
A. Temperature compensation B. Cannot use sevoflurane C. Small volume reservoir D. Flow compensation E.
D. Flow compensation
The OMV is reasonably accurate over a wide range of flow rates and tidal volumes and, in particular it performs well at small tidal volumes, making it suitable for paediatric anaesthesia (Update in Anaesthesia)
Disadvantages of drawover vaporiser:
- Decreasing familiarity with technique and equipment
- Lack of temperature compensation
- Filling systems not agent-specific
- Small volume reservoir (only 415 mL)
- Less easy to observe spontaneous ventilation with self inflating bag
- Cumbersome in paediatric use, unless lightweight tubing is available
Advantages:
- Simplicity of concept and assembly, with inherent safety
- No need for pressurised gas supply, regulators and flowmeters
- Minimum FiO2 is 0.21
- Robust, reliable, easily serviced equipment
- Low cost (purchase and maintenance)
- Portable, suitable for field anaesthesia
Sevoflurane has been used in draw-over, but its use is hampered by a need to deliver high percentages which are at the upper limits of simple vaporiser performance capabilities, as well as its high cost (Update in Anaesthesia), ie sevoflurane can be used
TMP-Jul10-037
Acute renal failure. Which is not an indication for dialysis?
A. Hyperkalaemia B. Metabolic alkalosis C. Hypernatraemia D. Uraemic pericarditis E. APO
B. Metabolic alkalosis
Indications for RRT (CEACCP 2006)
Classical:
- Volume overload
- Metabolic acidosis (pH 6.5)
- Symptomatic uraemia (pericarditis, encephalopathy, bleeding dyscrasia)
- Dialysable intoxications (lithium, ethylene glycol, methanol, aspirin, theophylline, vancomycin, procainamide)
- Hyperthermia (cooling)
Alternative:
- Endotoxic shock
- Hypothermia (rewarming)
- SIRS (pancreatitis, ARDS)
- Nutritional support
- Hepatic failure
- Deliberate hypothermia
- Severe dysnatraemia (Na 165)
- Traumatic rhabdomyolysis
- Plasmapheresis (GBS, MG, TTP)
TMP-Jul10-038
Chronic alcohol use. Which is not an associated complication?
A. Pancreatitis B. Atrial fibrillation C. Macrocytosis D. Nephrotic syndrome E. Hypertriglyceridaemia
D. Nephrotic syndrome
TMP-Jul10-039
Chest 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.
B. Roll onto right side
Turning suction on on the ICC will increase the tendency for mediastinal shift.
Increasing PEEP will further impede venous return.
Update on anesthetic management for pneumonectomy (Current Opinion in Anaesthesiology 2009)
• Acute cardiac herniation is an infrequent, but well described complication of pneumonectomy when the pericardium is incompletely closed or the closure breaks down. It usually occurs immediately or within 24h after chest surgery and is associated with more than 50% mortality. Cardiac herniation may also occur after a lobar resection with pericardial opening or in other chest tumor resections involving the pericardium or in trauma
Cardiac herniation following completion pneumonectomy for bronchiectasis (Annals of Cardiac Anaesthesia 2010)
• Heart-herniation may present when the patient is turned supine at the conclusion of the operation or in the very early postoperative period, usually within the first 24 hours. Factors precipitating it are application of negative pressure to the thoracostomy drainage tubes, positive pressure ventilation, coughing on extubation and positioning the patient with operated side dependent
• (In cardiac herniation)… three conservative measures to improve the cardio-respiratory function before patient transfer to the operation suite include repositioning the patient with nonsurgical side down, avoiding hyperinflation of the remaining lung and injecting 1-2 litres of air into the surgical hemithorax. Definitive treatment and prevention of recurrence require open surgery to reduce the hernia and repair the pericardial defect by prosthetic patch or autologous graft like fascia lata
TMP-Jul10-040
Salicylate poisoning:
A. Respiratory acidosis B. Metabolic acidosis C. Increased pCO2 (or increased CO2 production) D. High output renal failure E. Hypothermia
B. Metabolic acidosis
Salicylate poisoning can cause vomiting, tinnitus, confusion, hyperthermia, respiratory alkalosis (due to direct stimulation of central respiratory centres), metabolic acidosis, and multiple organ failure. Diagnosis is clinical, supplemented by measurement of the anion gap, ABGs, and serum salicylate levels. Treatment is with activated charcoal and alkaline diuresis or hemodialysis (Merck Manual)
TMP-Jul10-041
New onset atrial fibrillation in a 10 week pregnant lady. BP 150/90, HR 160, SaO2 92%. Moderate mitral stenosis on TTE, no thrombus seen. Emergency doctor gave her anticoagulant (not specified what). Most appropriate management:
A. Verapamil
B. Labetalol 20mg iv to 300mg
C. Amiodarone 300mg IV
D. Synchronised biphasic cardioversion with 70-100 Joule
E. Oral digoxin -1000mcg then 500mcg 6 hrs later
D. Synchronised biphasic cardioversion with 70-100 J
AF poorly tolerated in mitral stenosis (esp. in pregnancy). Cardioversion indicated if:
- Haemodynamically unstable
…or
- Onset
TMP-Jul10-042
Patient post anterior cervical fusion. Patient in recovery. Confused and combative. Nurse concerned about haematoma Taken to theatre: Most appropriate way of securing airway:
A. Gas induction / laryngoscopy / intubate
B. Awake tracheostomy
C. Awake fibreoptic intubation using minimal sedation
D. Thiopentone, suxamethonium, direct laryngoscopy and intubation
E. retrograde intubation
A. Gas induction/laryngoscopy/intubate
Cervical spine surgery - Postoperative airway obstruction (CEACCP 2007)
• Some degree of airway obstruction is not uncommon after anterior cervical surgery. It is sometimes because of a haematoma, but in many cases it is because of tissue swelling. It usually presents within 6 h, but can occur later. Airway obstruction is particularly likely after combined anterior–posterior cervical surgery.
• There are some important diagnostic points:
1. Stridor is unusual—the obstruction is because of swollen tissue in the supra and peri-glottic regions.
2. The patients say they ‘can’t breathe’ and want to sit up.
3. Oximetry may register almost normal values until very late.
4. The presence of a drain in the neck does not prevent swelling.
• Heliox, dexamethasone IV and nebulised epinephrine are all worth trying, but the priority is to open the wound, which may relieve tissue tension enough to restore an airway. Re-intubation may be difficult. The patients must be managed in a semi-sitting posture. Awake fibreoptic intubation is sometimes a good option, but direct laryngoscopy after sevoflurane and oxygen induction (with judicious doses of propofol) may be easier. The gum-elastic bougie is often vital and an LMA (± fibrescope, ± gum elastic bougie or Aintree catheter) or an ILMA-guided technique may save the day. The use of succinylcholine in myelopathic patients is hazardous because of abnormal potassium shifts.
• Airway obstruction because of bilateral recurrent laryngeal nerve palsy is rare, but unilateral nerve damage is seen from time to time and causes a ‘lowing’ cough and a weak voice.
TMP-Jul10-043
Young asthmatic male in emergency department. RR 26, pCO2 27, SAO2 92%, struggling talking in sentences. Given nebulised salbutamol, and ipratropium, 200mg IV hydrocortisone. After 30 minutes - no improvement. Further management:
A. IV salbutamol B. IV aminophylline C. IV magnesium D. Intubate and ventilate E. helium/oxygen mixture
C. IV magnesium
50 mg/kg over 20 mins followed by infusion at 30 mg/kg/h
TMP-Jul10-044
Called to emergency department to review a 20 y/o male punched in throat at a party. Some haemoptysis / hoarse / soft voice. Next step in management:
A. CT to rule out thyroid cartilage fracture
B. XR to rule out fractured hyoid
C. Rapid sequence induction / laryngoscopy / intubation
D. Awake fibreoptic intubation
E. Nasendoscopy by ENT in emergency department
E. Nasendoscopy by ENT surgeon in ED
TMP-Jul10-045 How quickly does the CO2 rise in the apnoeic patient?
A. 1 mmHg per min B. 2 mmHg per min C. 3 mmHg per min D. 4 mmHg per min E. 5 or ?8 mmHg per min
3-4 mmHg/min
TMP-Jul10-046 Long-standing T6 paraplegia. All present EXCEPT ?
A. Flaccid paralysis B. Poikilothermia C. Autonomic hypereflexia D. Labile BP E. Hyperkalaemia with suxamethonium
A. Flaccid paralysis
get spastic paralysis long-term
TMP-Jul10-047 Young female patient for tonsillectomy with history of bleeding tendency. Which is the most likely cause?
A. Factor V Leiden B. Protein C deficiency C. Haemophilia B (Christmas disease) D. Antithrombin III deficiency E. Lupus anticoagulant
C. Haemophilia B
all the others are procoagulant disorders
TMP-Jul10-048 Amniotic fluid embolism. Cause of death in first half hour?
A. Pulmonary hypertension B. Malignant arrhythmia C. Pulmonary oedema D. Hypovolaemic shock E.
A. Pulmonary hypertension
TMP-Jul10-049 Hypocalcaemia – earliest sign:
A. Tingling of face and hands B. Chvostek’s sign tapping of the inferior portion of the zygoma will produce facial spasms C. Carpopedal spasm D. E.
A. Tingling of face and hands
TMP-Jul10-051 Visual loss with pupillary reflexes retained. Likely cause?
A. Retinal detachment B. Occipital mass C. Frontal mass D. Chiasmal mass E. Optic neuritis
B. Occipital mass
Classic finding for cortical blindness (normal eyes, retinae and afferent and efferent pathways)
TMP-Jul10-052 Nerve block for anaesthesia over anterior 2/3 of ear?
A. C2 B. Mandibular nerve C. Maxillary nerve D. Ophthalmic nerve E. Vagus
B. Mandibular nerve
The auriculotemporal nerve (branch of V3) supplies sensation to the anterior portion of the external ear (including the tragus). The actual portion it covers is variable, depending on which picture you look at. Some pictures on google image show it covering the majority of the anterior ear, whereas others show it only covering a thin sliver.
The greater occipital nerve (from C2, C3) supplies the posterior portion.
The vagus nerve supplies the external auditory canal.
TMP-Jul10-053 Complex regional pain syndrome. What proportion of patients have motor involvement?
A. 0 % B. 25 % C. 50 % D. 75 % E. 100 %
D. 75%
?source
