Post-Written Los



PRIMARY LO OF THE DAY TRUE/FALSE QUESTIONS (In no particular order – sorry!)INHALATIONAL AGENTSTRUE/FALSE A partition coefficient of 1.4 means that at equilibrium the partial pressure in blood is 1.4 times that in the alveolus TRUE (if referring to blood gas partition coefficient, vs oil:gas)RememberHigher partition coefficient = higher lipophilicity = higher potency = higher solubilityHigher solubility = slower onsetFALSEPartial pressures are the same at equilibrium. It is the amount in each partition that is differentTRUE/FALSE Saturated vapour pressure increases with temperatureTRUESVP is measure of volatility of the liquid anaesthetic in the carrier gasIt is measured at 20 deg C and 760mmHg barometric pressureTRUE/FALSE Boiling point decreases with falling atmospheric pressureTRUEBoiling point is the point at which vapour pressure equals atmospheric pressure.Because at altitude, atmospheric pressure is lower, the vapour pressure of the liquid needs to be lower to reach boiling point. Therefore less heat is required to make the vapour pressure equal to the atmospheric pressure.TRUE/FALSE Maximum sevoflurane concentration at sea level is 33%FALSEMax conc % = (SVP / ATM pressure) x 100% 157/760 = .20657 = 21%Halothane is 33%; Isoflurane is 32%TRUE/FALSE Using desflurane in a sevoflurane vaporiser would result in a sub anaesthetic desflurane doseFALSEInitial overdose of anaesthetic, plus hypoxic gas mixture due to high SVP (669). Rapid CVS and CNS adverse effects due to low Blood:Gas partition coefficient. Would then have a rapid decrease in SVP due to temperature drop due to latent heat of vapourisation. TRUE/FALSE CYP3A4 is responsible for the oxidative metabolism of halogenated inhaled anaesthetic agentsFALSECytochrome P450 2E1TRUE/FALSE Desflurane is less likely to cause hepatitis than IsofluraneTRUEDesflurane has less metabolism by 2E1Halothane 20%, Sevoflurane 2% and Enflurane, 0.2 Isoflurane and 0.02 DesfluraneRare cases of isoflurane hepatotoxicity similar to that of halothane due to immunogenic reactive intermediates TRUE/FALSE Intrarenal metabolism of methoxyflurane can lead to oliguric renal failureFALSEHigh output renal failure with fixed specific gravity/poorly concentrated urine. Vasopressin resistant. TRUE/FALSE Compound A exposure during anaesthesia causes a transient rise in blood creatinine and urea in humansFALSECompound A is a dose-dependent nephrotoxin in rats however threshold in Humans is controversial. Some studies demonstrate tranisent changes, however bulk of studies do not. However, FDA recommends fresh FGF of 1L/min for up to 1 hour and 2L/min for >1hr to avoid clinically significant levels of compound ATRUE/FALSE Desflurane and Sevoflurane may produce signifcant quantities of carbon monoxide when used with dry CO2 absorbentsTRUECO2 absorbers contain strong bases that can extract labile protons from anaesthetic molecules resulting in CO. Soda Lime and Baralime can result in >30% CO.Des > enflurane > isoflurane > halothane > sevoAnd Baralyme > Soda limeTRUE/FALSE Nitrous oxide produces analgaesia through actions on opioidergic neurons in the periaqueductal gray matterTRUEN2O analgesic effect abolished by naloxone. Thought to stimulate encephalin which bind to opioid receptors that trigger descending noradrenergic pathwaysTRUE/FALSE Inhaled anaesthetic agents probably have their action through inhibition of axonal propagationTRUE (? Not completely explained)Molecular mechanisms still poorly understood. Evidence supports effects on membrane proteins including ligand and voltage gated ion channels of excitable cellsTRUE/FALSE Halogenated inhaled agents increase the affinity of the GABA receptor for GABATRUEHalogenated inhaled agents potentiate GABA A receptors and two-pore domain K channels. Whereas N2O and Xe inhibit NMDA channelsTRUE/FALSE Inhaled anaesthetics most likely have their action by perturbing the biophysical properties of lipid bilayersTRUE (? Not completely explained)According to the modern lipid hypothesis, anesthetics do not act directly on membrane protein targets but rather perturb specialized lipid matrices at the protein lipid interface which act as mediators. This then affects ion channel function.TRUE/FALSE Nitrous oxide has similar vasodilating effects to sevofluraneFALSETRUE/FALSE Desflurane abolished autoregulation of cerebral blood flow at 0.7 MACFALSEAt 0.7 MAC it is impaired but presentAt 1- 1.5MAC it is abolishedTRUE/FALSE Sevoflurane reduces pulmonary vascular resistanceTRUEN2O increases it. Others decrease it.TRUE/FALSE Sevoflurane should not be used above 1.3 MAC because of the risk of coronary stealFALSEVolatiles increase coronary blood flow many times beyond that of myocardial oxygen demand, thereby creating potential for steal. Coronary steal is diversion of blood from myocardial bed with limited or inadequate perfusion to a bed with more adequate perfusion (when autoregulation still present) TRUE/FALSE Sevoflurane causes a dose dependent decrease in hepatic arterial blood flowFALSEDecreases with halothane and enflurane onlyPRIMARY LO OF THE DAY – PHARMACOKINETICS & PHARMACODYNAMICSAntagonist drugs have no intrinsic activity TRUE/FALSETRUEHave affinity but no intrinsic activityQuantal dose response curves look at the response of an individual to varying doses of a drug TRUE/FALSEFALSEQuantal dose response curve is all or nothing. It describes the number of patients showing response at a SPEFICIC doseGraded dose response curve shows the relationship between the magnitude of effect of a drug in a patient and at the varying doses of a drugTherapeutic index is derived from quantal dose response curves TRUE/FALSETRUETherapeutic index is ratio of the dose that produces toxicity to the dose that produces clinically desirable response in a population of individuals. (TD 50 / ED 50)Both ED 50 and TD 50 are calculated from quantal dose response curves which represent the frequency with which each dose of drug elicits the desired response or toxic response in the population.Potency of a drug can be deduced from both a graded and quantal dose response curve TRUE/FALSETRUEPotency = amount of drug needed to produce a given effect. In Graded dose response curves the effect usually chosen is 50% of the maximal effect and the concentration that causes this effect, potency determined by the affinity of the receptor for the drug and number of receptors availableIn Quantal dose response curves, potency is measured by ED50, TD50 and LD50, ie. Median effective, toxic, and lethal doses respectively, in 50% population studied)A competitive antagonist will reduce the maximum efficacy of the agonist drug TRUE/FALSETRUEFALSE, see Peck and Hill p 35Only non-competitive antagnoists will reduce the maximum efficacyDiastereoisomers are two molecules that are mirror images of each other, because they have one chiral centre. TRUE / FALSEFALSEDiasteroisomers are stereoisomers with two or more stereocentres that are NOT mirror images of one another and are NOT superimposable on one another. Adrenaline preparations are racemic. They contain levo-adrenaline and dextro-adrenaline, which are equipotent. TRUE / FALSEFALSEIt is racemic – levo is 10 x more potent than dextroRopivacaine contains only the S isomer, which has lower toxicity than the R isomer. TRUE / FALSETRUEDue to different affinity on ion channelsIntravenous glucose solutions contain only D-glucose, because L-glucose cannot be used by cells. TRUE / FALSETRUEL – glucose cannot be phosphorylated to hexokinase which is the first enzyme in the glycolysis pathwayS-ketamine is not currently available in Australia. It would be advantageous, because the R enantiomer causes more hallucinations. TRUE / FALSEFALSE*The incidence of psychological side effects is the same with each at equal plasma concentrations.However, because S ketamine more potent, smaller dose used and therefore may have less hallucinations than R Monitoring of neuromuscular blockadeTRUE/FALSE Response to repeated single twitches at 1Hz is greater than at 0.1HzFalse ?- ?At frequencies above 0.15Hz, the response will gradually decrease and settle at a lower level ? agreesTRUE/FALSE In the late phase of recovery after muscle relaxant administration, tetanic stimulation can cause lasting antagonism of neuromuscular blockadeTRUEReference as aboveTRUE/FALSE The post tetanic count at which the first twitch on the train of four (TOF) appears is similar for both atracurium and cisatracuriumTrue - millerTRUE/FALSE To completely prevent the bucking response to carinal stimulation the post tetanic count needs to be zeroTRUE – Miller fig 53.6TRUE/FALSE If no fade is felt with dual burst stimulation the train of four ratio is above 0.7FALSE! Dual???MEASUREMENT OF BLOOD PRESSURETRUE/FALSE ?The natural resonant frequency of a system is proportional to the stiffness or tension in the system, and inversely proportional to the mass.TRUEHence – decreased compliance and increased density (ie. Clots) – decr natural frequency of arterial set upAlso Increased length decr nfTRUE/FALSE ?As in tightening a violin or guitar string, increasing the stiffness or tension will lead to an increase in the natural resonant frequency (a higher note on the instrument)TRUETRUE/FALSE ?Like the pendulum of a grandfather clock being slower than that of a cuckoo clock on the wall, the pulmonary artery tracing on the monitor is not as good as the arterial system, as the pulmonary artery system has a much longer system and as such more mass and a lower natural frequency?TRUEHas a lower natural frequency because LONGER tubing and hence INCR massTherefore high frequency artefactsTRUE/FALSE ?The ideal system for an arterial monitoring system has a large length and very stiff tubing to ensure that its natural frequency is close to the frequency of the system being monitoredFALSETRUE/FALSE ?The ideal frequency for a pressure monitoring system is determined by the pressure range being measured, rather than by the frequency of the system.TRUEArterial BP - Heart rates 30 ~ 180 bpm correspond to fundamental frequencies of 0.5 ~ 4 HzFALSE, the frequency characteristics are independent of the pressures measured. The natural frequency (resonant frequency) of the measuring system should be at least 8 times the fundamental frequency of that being measured. 180bpm = 3 hz * 8 = 24hzDynamic airways closureDynamic airways closure may occur during normal tidal breathing TRUE/FALSE TRUE?Dynamic airway closure accounts for the effort dependent portion of the expiratory limb of the flow-volume loop TRUE/FALSEFALSEEffort Independent component Starlings resistor – Alveolar pressure – INTRPLEURAL pressure (not mouth)During forced expiration, positive pressure generated will be transmitted equally across the respiratory system TRUE/FALSEFalseDecreases along length of airwayThe trachea is never subject to dynamic airway closure TRUE/FALSEFALSEExcessive dynamic airway collapse (EDAC) defines the pathological collapse and narrowing of the airway lumen by >50%, which is entirely due to the laxity of the posterior wall membrane : Pierdonato Bruno1During the effort independent part of an expiratory flow volume loop, maximum air flow rate is determined by lung volume TRUE/FALSETRUEMaximal flow decreases with lung volume – FIG 7.16 WESTMeasurement of blood pressureTRUE/FALSE ?System A is an example of a system where the natural resonance frequency of the system is similar to that being measured.TRUE?Underdamped definitelyAssuming higher amplitude in oscillationsAny further takes?FALSE, it’s just underdampedIf the natural frequency of the system was equal to the fundamental frequency of the measured waveform, it would continue to oscilate indefinitelyTRUE/FALSE ?System B is the most ideal for a blood pressure measurement response because it provides the most accurate reading.FALSEOverdampedTRUE/FALSE ?System C is an example of optimal damping as it provides a rapid response with minimal sacrificing of accuracyTRUEDamping coefficient 0.64TRUE/FALSE ?In all systems the eventual measured pressure will be accurate FALSEMAP will be accurateTRUE/FALSE ?Damping is a reduction in the amplitude of an oscillation as a result of energy being drained from the system to overcome frictional or other resistive forces.TRUEOXYGEN ANALYSISTRUE/FALSE An operating room paramagnetic analyser incorporates a pressure transducerTRUE - ?alternating pressure at the transducer, the magni- tude of which is a measure of the oxygen partial pressure in the sample gas. NOTE – old types had dumb bellTRUE/FALSE ?Pressure exerted on the side of a tube decreases as flow rate increasesTRUE ?Bernoulli’s principle?TRUE/FALSE ?Nitric oxide at clinically used concentrations will falsely increase oxygen concentration in a paramagnetic analyser used in theatreFALSENitric oxide and O2 measured using PMGANITROUS OXIDE or water vapour affects accuracy – Dr Podcast scriptTRUE/FALSE ?Paramagnetic analysis degrades oxygen molecules into free radicals so the gas cannot be returned to the circuitFALSETRUE/FALSE ?Oxygen tension can also be measured with infrared analysisFALSE ?- only diatomic moleculesOXIMETRYTRUE/FALSE ?Response time is faster when the oximeter is on the earlobe cf the fingerTRUETRUE/FALSE ?Bilirubinaemia can result in a falsely low oxygen saturation with pulse oximetryFalseTRUE/FALSE ?The percentage of the signal which is pulsatile in finger pulse oximetry is approximately 80%FALSEAbout 2% - TRUE/FALSE ?Anaemia may cause under-reading of oxygen saturations with pulse oximetryFALSEAnemia or polycythaemia does not affect pulse oximetry but needs to be considered as total O2 content may be lowTRUE/FALSE ?A pulse oximeter will detect a drop in oxygen tension from 600mmHg to 200mmHgFALSE ?OXIMETRYTRUE/FALSE A pulse oximeter radiating 2 wavelengths of light can only differentiate 2 different forms of Hb.TRUE TRUE/FALSE Oxygenated haemoglobin absorbs light at a wavelength of 660nm.TRUETRUE/FALSE The y axis on the plethysmograph is an estimate of arterial calibre and thus sympathetic tone.NOT SUREWTF? Any takersAC: yep, I think the width of the pulse wave correlates to arterial caliber, like with the art line. I have read this somewhere.TRUE/FALSE Methaemoglobin is strongly absorbed at 660 and 940nmTrueTRUE/FALSE An adult pulse oximeter cannot accurately read oxygen saturations when foetal haemoglobin is present.False – but may cause false low/No offect frca Anesthetics Part 1Duration of action of a local anaesthetic is primarily determined by the pKa of the agent ?TRUE/FALSEFALSE – protein binding Increasing the dose of local anaesthetic will increase the duration of action TRUE/FALSETRUEBenzocaine is only suited to topical anaesthesia due to its lipophilicity TRUE/FALSETrueAll local anaesthetics EXCEPT ropivicaine cause vasodilation TRUE/FALSEFALSE - cocaineAdding bicarbonate to a local anaesthetic solution hastens the onset of action TRUE/FALSETrueLocal Anaesthetic Part 2Early excitatory signs of neurotoxicity are due to activation of excitatory interneurons TRUE/FALSEFALSEInitial signs due to blocking CNS inhibitory pathwaysHigh foetal plasma concentrations of local anesthetic are a result of higher α1-acid glycoprotein concentrations in the foetus TRUE/FALSEFALSEAt term fetus contains higher levels of albumin than mum, but alpha 1 acid glycoprotein in fetus never attain maternal valuesMethaemaglobinaemia from prilocaine toxicity results in a right shift of the oxygen haemaglobin dissociation curve TRUE/FALSEFALSEMethb shifts to the leftAll local anesthetics exert dose-dependent negative inotropic action on cardiac muscle TRUE/FALSETRUEThe CNS effects of local anesthetics may contribute to the generation of arrhythmias TRUE/FALSE TRUEANALGESICSParacetamol and Ketamine both exert analgesic effects via NMDA receptors TRUE/FALSEFALSEParacetamol has poor bioavailabilityv TRUE/FALSEFALSEHepatotoxicity is an uncommon, immune mediated complication of paracetamol use TRUE/FALSEFALSESubanaesthetic doses of ketamine achieve analgesia via a specific competitive NMDABlockade TRUE/FALSE TRUENaloxone is minimally effective in reversing the effects of?tramadol TRUE/FALSE TRUEhe clinical usefulness of ketamine as an analgesic is limited by apnoea TRUE/FALSEFALSEmainly limited by dissociative/emergence effectsTRUE/FALSE Ketamine binds competitively to the phencyclidine recognition site on N-methyl- d-aspartate (NMDA) receptorsFALSETRUE/FALSE Ketamine is metabolised via the cytochrome p450 system to inactive metabolitesFALSEActive metabolitesTRUE/FALSE Ketamine has no pharmacological action on opioid receptorsFALSEActs on kappa receptorsTRUE/FALSE Ketamine may play a role in the modulation of spinal cord sensitization predominantly via its action on mu opioid receptorsFALSEVia NMDA receptor, not opioidANTIBIOTIC PROPHYLAXISTRUE/FALSE Clindamycin may cause foetal toxicity if given before delivery at Caesarean SectionFALSETRUE/FALSE A positive Coombs reaction with cephalosporins is associated with haemolysis in 10-20% of patients?TRUE/FALSE Cefazolin provides better prophylaxis than cephalothin because it has slower renalexcretionTRUETRUE/FALSE First generation cephalosporins are microbials of choice for uncomplicatedgenitourinary proceduresFALSENeed gram negative coverTRUE/FALSE Single dose antibiotic prophylaxis is the second most common cause of in hospitalmicrobial resistanceFALSEREVERSALSTRUE/FALSE?Maximum effect of neostigmine reversal of rocuronium occurs after 10 minutesTRUETRUE/FALSE?Neostigmine does not inhibit plasma (butyryl)cholinesteraseFALSETRUE/FALSE?Neostigmine can provoke bronchospasmTRUETRUE/FALSE?Sugammadex should be avoided in patients with creatinine clearance of < 30mL per minuteFALSE **Caution but still useTRUE/FALSE?4mg/kg of sugammadex is sufficient to reverse neuromuscular blockade with rocuronium if the post tetanic count is greater than 2FALSEPTC >2 need 16mg/kgAUTONOMIC NERVOUS SYSTEMTRUE/FALSE ?Acetylcholine is the neurotransmitter released from all pre-ganglionic autonomic neuronsTRUETRUE/FALSE ?Acetylcholine is released from all post-ganglionic parasympathetic neurons except those that innervate sweat glandsFALSETRUE/FALSE ?The adrenal medulla is innervated by inhibitory parasympathetic neuronsFALSETRUE/FALSE ?Plasma concentration of acetylcholine are low predominantly due to pseudocholinesteraseFALSETRUE/FALSE ?Nicotinic acetylcholine receptors mediate transmission at autonomic gangliaTRUEREGULATION OF OSMOLARITYThe factors that regulate vasopressin secretion also regulate thirst TRUE/FALSETRUEAng II, SNSVasopressin is synthesised in the posterior pituitary TRUE/FALSEFALSESynthesized in hypothalamusMost of plasma’s osmolality is due to Na+ and its accompanying ions, CL- and HCO3- TRUE/FALSETRUEHypovolaemia stimulates thirst via angiotensin II acting at sites outside the blood brain barrier TRUE/FALSETRUEAldosterone is responsible for regulating plasma osmolality TRUE/FALSETRUEFOETAL CIRCULATIONWithin the umbilical cord, there are two veins, and one artery. TRUE / FALSEFALSE1 umbilical vein, 2 umbilical arteriesFoetal blood returning from the placenta has an oxygen saturation of 80%. TRUE / FALSETRUEThe foramen ovale remains open in the foetus under the influence of prostaglandins. TRUE / FALSEFALSEThe ductus arteriosus adds blood into?the aorta distal to the vessels supplying the brain. TRUE / FALSETRUEFollowing delivery, there is a “transitional” circulation. Target SpO2 levels for a neonate are: 70-90% at 3 mins, and 85-90% at 10 mins. TRUE / FALSETRUEIt may take up to 1 hour to achieve sats >95%Found this in Circ (2005), Neonatal resusc guidelinesMUSCLE PHYSIOLOGYTRUE/FALSE?Most muscle fibres have only one neuromuscular junction.TRUEEach?muscle fiber has?one?neuromuscular junction, receiving input from?just one?somatic efferent neuron. TRUE/FALSE?Activation of skeletal muscle acetylcholine receptors caused depolarisation by efflux of K+ ions.FALSEThis would cause hyperpolarizationTRUE/FALSE?ATP can only supply energy for skeletal muscle contraction for 5-8 seconds.FALSE Only 1-2 s TRUE/FALSE?In the final stage of denervation atrophy, muscle cells have little capability to regenerate myofibrils.TRUETRUE/FALSE?Skeletal and cardiac muscle act as a functional syncytium during depolarisation.FALSEOnly cardiacAIRWAY PHYSIOLOGYNasal breathing provides better humidification than mouth breathing TRUE/FALSETRUEThe afferent impulses for lung reflexes are mediated via the vagus nerves TRUE/FALSETRUECough, hering -breuer reflexPharyngeal dilator muscles contract reflexively during normal inspiration to prevent pharyngeal obstruction TRUE/FALSETRUEThese impaired in OSAThe expiration reflex may be stimulated at the larynx and sites lower in the airway TRUE/FALSETRUEForced expiratory effort against a closed glottis that opens to eject laryngeal debris to prevent aspiration of material. Larynx, cords, tracheobronchial treePharyngeal reflexes are maintained, unchanged, during sleep TRUE/FALSEFALSECVS PHYSIOLOGYThe heart only has to work against afterload once the aortic and pulmonary valves are open and ejection of ventricular blood begins TRUE/FALSEFALSEIf afterload and contractility remain unchanged, increasing preload will result in a decreased end-systolic ventricular volume TRUE/FALSEFALSEWill result in increased stroke volume. But ESV will remain sameIn sinus rhythm, atrial contraction contributes about 30% to the end diastolic ventricular volume TRUE/FALSETRUEA Frank Starling curve relates ventricular end diastolic volume to left ventricular pressure TRUE/FALSEFALSEx axis is ventricular end diastolic volumey axis is stroke volumeIn normovolaemic patients, IPPV causes an increase in cardiac output TRUE/FALSEFALSEThe blood volume impacts on the cardiovascular responses of a patient undergoing the Valsalva Manoeuvre ?TRUE/FALSEFALSEPneumoperitoneum with an intraabdominal pressure of greater than 10mmHg is likely to result in an increase in cardiac output TRUE/FALSEFALSEOverall decrease CO by 10-30%Compensation which occurs following haemorrhage, aims to restore arterial blood pressure to normal TRUE/FALSEFALSEPrimary aim is to restore perfusion Sympathetic stimulation associated with major haemorrhage results in significant coronary artery constriction TRUE/FALSE? FALSEThe baroreceptor setpoint changes during excersice TRUE/FALSETRUERenalBT_PO 1.63 Describe glomerular filtration and tubular functionDaily glomerular filtration of potassium is?approximately 800 mmol/day. TRUE / FALSEFALSE600mEq/dayVander p 134 (4mEq/l and GFR 150 L/day)But Kam says 900Reabsorption of potassium in the proximal tubule is fixed at 65% of the amount filtered. TRUE / FALSEFALSE65% reabsorbed in proximal tubule, but the flux is unregulated and varies with how much sodium and water is reabsorbed (Vander p 134)Aldosterone controls potassium excretion by altering the amount reabsorbed in the distal tubule. TRUE / FALSETRUE?I think so, but Vander is unclear that the increase in N/K/ATPase and the epithelial sodium channel ENaC is in the distal tubule, p40An increase in plasma potassium concentration directly stimulates the Na-K pumps in the distal tubule, to increase potassium secretion. TRUE / FALSETRUEVander p138During hypokalaemia, the kidneys can achieve zero potassium excretion in the urine. TRUE / FALSE?FALSEVander says in potassium depletion 2% of filtered load is in urine p 135Physiology of the airwayBT_AM 1.2 Describe the physiology of the airway including airway reflexesNasal breathing provides better humidification than mouth breathing TRUE/FALSETRUENunn, p3The afferent impulses for lung reflexes are mediated via the vagus nerves TRUE/FALSETRUENunn p57Pharyngeal dilator muscles contract reflexively during normal inspiration to prevent pharyngeal obstruction TRUE/FALSETRUE? At least the first part isNunn p52 expiration reflex may be stimulated at the larynx and sites lower in the airway TRUE/FALSE?FALSE, definitely occurs from the larynx, not sure about belowNunn p56Pharyngeal reflexes are maintained, unchanged, during sleep TRUE/FALSEFALSE, Nunn p236BT_PO 1.37 The stressed respiratory systemTRUE/FALSE ?FRC in healthy adult males, is reduced by approximately 500ml when supineTrueNunn p29Range 500-1000mlTRUE/FALSE ?Ventilatory adaptation to high altitude takes approximately one weekTRUE,Nunn p 249 (graph)TRUE/FALSE ?During bag/mask ventilation, total dead space (apparatus and physiological) comprises approximately half the tidal volumeFALSE, 0.68Nunn p 306TRUE/FALSE ?FRC reduces with ageFALSENunn p27TRUE/FALSE ?Increased respiratory resistance in obesity is mostly due to increased airways resistanceFALSE, but I don’t have a reference, can’t be totally sureBT_PO 1.83 Describe the physiological consequences of starvationProlonged starvation reduces immune function TRUE/FALSEI can’t find shitBrain and nerves, renal medulla, red blood cells are obligate glucose consumers TRUE/FALSE?FALSE, brain can use ketone oxidationPower and Kam, p 375Renal medulla and RBCs use glucose, which can be synthesized via gluconeogenesis but not sure if obligateAdaptive reponses to starvation aim for conservation of energy and protein TRUE/FALSEI can’t find shitMuscle glycogen is freely available as a source of blood glucose TRUE/FALSEI can’t find shitDuring starvation, the gastrointestinal tract has an enhanced ability to digest food TRUE/FALSEI can’t find shitBT_PM 1.26 Describe the location and role of NMDA receptorsTRUE/FALSE The NMDA receptor is involved in development of tolerance to opioids.TRUE, ishPower and Kam p 402TRUE/FALSE Glutamate acts at NMDA receptors in the dorsal horn.TRUEPower and Kam p398TRUE/FALSE The resting NMDA receptor is blocked by magnesium.TRUEPower and Kam p400TRUE/FALSE Activation of postsynaptic NMDA receptors causes influx of sodium and calcium.TRUEPower and Kam p 400 diagramTRUE/FALSE Presynaptic NMDA receptor activation reduces cell excitability.???BT_PM 1.8 Pain in the ElderlySee acute pain manualTRUE/FALSE Opioid receptor density is decreased in the brain and spinal cord of the elderlyFALSE, decreased in brain not spinal cordTRUE/FALSE Older people have a reduced ability to tolerate intense painTRUETRUE/FALSE Autonomic responses to pain are blunted in dementiaTRUETRUE/FALSE There is a lower threshold for temporal summation of painful thermal stimuli in the elderly? TRUETRUE/FALSE Primary hyperalgaesia resolves more slowly in the elderly than the youngFALSEBT_RT 1.8 Outline the changes that occur in stored bloodTRUE/FALSE Granulocytes loose their antigenic properties within 4-6 hours of collectionTRUE/FALSE Plasma K+ concentration reaches approximately 30mmol/L at 28 daysTRUE/FALSE Factor VIII levels decrease to 50% at 21 daysFALSEDecrease to 50% at 24 hours: BrandisTRUE/FALSE 10-20% of red cells transfused at maximum storage time are destroyed within 24 hoursTRUERoughly, MillerTRUE/FALSE 2,3 DPG levels fall by 95% within 14 days of collectionBT_PO 1.37 Discuss the effect of the following on ventilation:TRUE/FALSE Periodic breathing while asleep leading to oxygen saturations of 50% is common when first ascending over 4000 mFALSEI don’t’ think so, Nunn was “Severe apneas can result in considerable additional hypoxeamia at high altitude, but in most cases mean SaO2 is maintained”.TRUE/FALSE Minute ventilation is proportional to oxygen consumption at all levels of exerciseFALSEMV increases disproportionally to Vo2 at Owles point. Nunn p 231TRUE/FALSE Response to hypoxaemia and hypercapnia are usually unaffected by obesityTRUE/FALSE FRC is reduced to a greater extent during anaesthesia, when a muscle relaxant is used than when one is not usedFALSENunn p 297TRUE/FALSE 1 MAC of anaesthesia preserves diaphragmatic function but can abolish EMG activity of other inspiratory muscles (If this is true how would this affect your anaesthesia plan for renal and ureteral lithotripsy?)TRUENunn 296Post-Written LosBT_SQ 1.6 Describe the methods of measurement applicable to anaesthesia, including clinical utility, complications and sources of error in particular:TRUE/FALSE If exhaled gas is not warmed to patient temperature in a pneumotachograph, volume will be underestimatedI guessTRUE/FALSE Volume is the area under a flow/time curveTRUE. Flow = Volume/Time, therefore Volume = Time *Flow = AUCTRUE/FALSE A pneumotachograph calculates flow from a known resistance and a measured pressure differenceYesTRUE/FALSE A pneumotachograph uses the hydraulic version of Ohms LawYesBT_GS 1.59 Describe the pharmacological principles of and sources of error with target controlled infusionTRUE/FALSE Inaccurate drug delivery from the infusion pump contributes to 55% of the overall inaccuracy of a TCI infusionTRUE/FALSE With most modern TCI algorithms actual plasma concentrations are within 20-30% of predicted concentrations 95% of the timeTRUE/FALSE The Marsh model uses age and weight to calculate the compartment sizeFalseTRUE/FALSE The Schnider model may calculate a negative lean body mass in very obese patientsTrue TRUE/FALSE The most clinically reliable method is to target the effect site concentration observed at loss of consciousness.? TrueBT_PM 1.18 Describe the pharmacology of opioids deposited in the epidural space or cerebrospinal fluidTRUE/FALSE The analgaesic effect from continuous epidural infusion of hydroPHILIC opioids is primarily from systemic absorptionFalse – only small amountTRUE/FALSE Intrathecal morphine provides analgaesia to more spinal levels than intrathecal fentanylTrue – decrease liophilicity = Incr potencyTRUE/FALSE Significant amounts of epidural morphine are sequestered in epidural fatFalse – more with fentanylTRUE/FALSE Epidural infusion of fentanyl may lead to systemic concentrations high enough to produce pharmacological effectsTRUE/FALSE The peak period for respiratory depression with intrathecal morphine is from 18-24 hours after injectionFalse – 12-16 hoursBT_GS 1.23 Describe the physical properties of inhalational agents, including the principles of vaporizationT / F At sea level the carrier gas leaving a sevoflurane vaporising chamber always contains approx. 21% sevoflurane.?False - AT 20 degrees and varries with splitting ratioT / F With increasing altitude, a vaporiser progressively delivers a lower partial pressure of anaesthetic than what is intended..False – only tec 6T / F At their boiling point, all substances have a saturated vapour pressure equal to the atmospheric pressure.TrueT / F A liquid becomes cold as it is vaporised, because heat energy contained in the liquid is converted to kinetic energy in the molecules which are escaping as a vapour.TrueT / F To maintain a constant temperature of the liquid anaesthetic, vaporisers are constructed of a good insulator such as copper.TrueOur vaporisers are often referred to as “plenum” vaporisers. What does plenum mean in this context?The anaesthetic apparatus shown above includes a vaporiser. How does it work in conjunction with the breathing system shown?BT_GS 1.23 Describe the physical properties of inhalational agents, including the principles of vaporisation BT_GS 1.26 Describe the toxicity of inhalational agentsPenthrane inhaler shownT / F Using the device shown above, a high inspired concentration of methoxyflurane can be achieved because it has a high saturated vapour pressure.FALSET / F Methoxyflurane is more potent than sevoflurane.TRUE, MAC 0.15%T / F Methoxyflurane produces analgesia at sub-anaesthetic concentrations.YEST / F The oil:gas partition coefficient is 950. This means, at equilibrium, the partial pressure of methoxyflurane in fat would be 950 times higher than in alveoli.FALSE, concentration would be, but partial pressure is the sameT / F Nephrotoxicity can occur with prolonged methoxyflurane use, due to intra-renal metabolism to inorganic fluoride (F?).TRUEBT_GS 1.23 Describe the physical properties of inhalational agents, including the principles of vaporizationFig 1. The above image shows an “open ether” anaesthetic (ether being dripped onto a wire mask covered with gauze).T / F It is possible to use ether as shown in Fig. 1 because it is very potent, with a low MAC.TRUET / F The patient in Fig. 1 is breathing room air. Administering open ether could cause the inspired oxygen concentration to be significantly reduced. (Can you explain your answer?)TRUE (SVP is 290.8T / F (If you understand the answers to the first 2 questions, this one should be easy!) The boiling point of ether is lower than sevoflurane.TRUE (34.6 vs 58.5Fig 2. Isoflurane vaporiserT / F This device might contain a bimetallic strip, to provide flow compensation.TRUET / F If you (hypothetically!!) filled this vaporiser with sevoflurane, the % shown on the dial would be lower than the % delivered to the patient.TRUE, Sevo SVP 170, Iso SVP 240BT_PO 1.126 Explain how the body defends against infectionT / F IgG antibodies are released from memory B cells (plasma cells) as part of a secondary (learned) immune response.TrueT / F “Innate” immunity would include intact mucosa, stomach acid, and lysozyme, but not neutrophils.False – Physical, humoral (complement), cellular (neutrophils)T / F Administering tetanus vaccine is an example of an “active” way of providing acquired immunity.True(Passive – antibodies trasferred from maternal through placenta to fetus)T / F The passive immunity provided to a neonate by trans-placental antibodies only lasts for about 1 month after birth.False – 3=6 monthsT / F The complement cascade results in lysis of bacteria. This can only be activated when IgG or IgM antibodies are bound to the bacteria.? trueBT_PO 1.99 Outline the pharmacology of anti-depressant, anti- psychotic, anti-convulsant, anti-parkinsonian and anti- migraine medicationFluoxetine significantly inhibits cytochrome P450 enzymes T/FTrueNortriptyline is usually better tolerated in the elderly than amitriptyline T/FTrue (secondary amine cf amitrip which is teritray)There is a significant risk of serotinergic syndrome when SSRIs are given with tapentadol T/FFalseChronic lithium therapy has no effect on MAC of inhaled anaesthetics T/FFalseHaemodyalisis is effective in the treatment of tricyclic antidepressant toxicity T/FFalseBT_GS 1.3 Define and explain dose-effect relationships of drugs with reference toA quantal dose-response curves has axes of dose and proportion of population responding ( or % responding) T/FTrueThe sigmoid shape of a quantal dose-response curve is because it is an example of a cumulative frequency distribution T/F ? MaybeQuantal dose response curves show a graded response in a population T/FFalseDrug potency can be assessed using quantal dose-response curves T/FTrue – eg. ED 50Muscle relaxant dosing, using 2xED95 is determined from the ED50 on a quantal dose-response curve, where the quantal response is 95% twitch height reduction T/FFalseWHY DO WE LOG quantal or graded curve for dose reponse? SO that responses are summated, to produce a cumulative frequency distribution sigmoid curve which is easier for comparison of potency 1.97 Describe the dynamics and metabolism of cerebrospinal fluidThe blue line represents CSF production, which is independent of intraventricular pressure T/FTrue Blue – production (independent on CIP, dependent on CPP)CSF reabsorption is zero when CSF pressure is low T/FTrue Red – absorption line, linearly increases with rise in ICPAt normal CSF presssure, production of CSF is greater than reabsorption T/FTrue (7 cm H2O); ABOVE 112 mm CSF or 11.2 cmH20 reabsorption greaterIncreased absorption of CSF is a indefinite means of compensating for rising ICP T/F?True CSF is a filtrate of plasma T/F (no help from the graph there ? )TrueSS_OB 1.9 Describe the influence of pregnancy on the pharmacokinetics and pharmacodynamics of drugs commonly used in anaesthesia and analgesiaTRUE/FALSE In pregnancy the average gain of 8 litres of total body water significantly increases the volume of distribution of hydrophilic drugs.TrueTRUE/FALSE Foetal and placental tissues provide another compartment for drug distribution.TrueTRUE/FALSE Pseudocholinesterase activity is decreased in pregnancy causing prolongation of succinylcholine block.FalseTRUE/FALSE Pregnancy reduces MAC by 25-30%.TrueTRUE/FALSE Nociceptive response thresholds are elevated in pregnancy.True - ?Incr endorphinsBT_PO 1.94 Outline the basis of the electroencephalogramT / F The frontal EEG is a mixture of electrical signals derived from the cerebral cortex as well as sub-thalamic structures and the limbic system.TrueT / F An “activated” EEG means that the amplitude of the EEG waveform is reduced.T / F The amplitude of an awake EEG is about the same as the p-wave on a standard ECG.T / F The amplitude of the EEG decreases with age.T / F “Burst suppression” is defined as periods of electrical activity alternating with periods of isoelectric EEG.TrueBT_GS 1.52 Explain the principles involved in the electronic monitoring of depth of sedation, including EEG analysis.T / F The EEG during sevoflurane anaesthesia has less “randomness” than when awake.TrueT / F Propofol causes burst-suppression of the EEG at levels which have little effect on spinal reflexes.T / F When burst-suppression is induced by propofol, total brain oxygen consumption is reduced by up to 90%.T / F Nitrous oxide causes similar changes to the EEG compared to sevoflurane.T / F Electrocortical silence cannot be produced with ketamine.TrueBT_GS 1.51 Describe the concept of depth of anaesthesia and how thismay be monitoredBT_GS 1.52 Explain the principles involved in the electronic monitoring ofdepth of sedation and anaesthesia, including the use of EEGanalysisWhat is “depth of anaesthesia”? How is it different from “level of consciousness”?Anaesthetic depth is the degree to which the central nervous system (CNS) is depressed by a general anaesthetic agent, depending on the potency of the anaesthetic agent and the concentration in which it is administered. The signs of this classical Guedel's classification depended on the eyelash reflex, respiration, eyeball movements, pupillary size, and muscular movements among others.Can you define these concepts in a way that does not rely on an electronic device?T / F Depth of anaesthesia refers to the effect of anaesthetic drugs on the brain only.T / F The BIS index is generated by combining together at least 3 different measures of EEG activity.T / F A BIS index under 60 means that a patient will not respond to voice.T / F The BIS index decreases during natural sleep, but not below 50.T / F Both the BIS and Entropy monitors analyse EEGs using frequencies at which muscle activity is significant.Placental Transfer of DrugsIonised drugs are more likely to cross the placenta compared with non-ionised drugs - FalseHeparin is safe to use in pregnancy because its large molecular size prevents it crossing the placenta T/FWeakly basic drugs, with a pKa less than 7.4, may become concentrated in the fetal compartment secondary to increased levels of ionisation FalseThe placenta is capable of metabolising some drugs presented to it T/FFor highly lipid soluble drugs, degree of protein binding is an important factor in the rate of placental drug transfer TrueOpioid ROUTESFentanyl undergoes significant first pass pulmonary uptake and metabolism False no metabolismThe cytochrome P450 3A4 (CYP3A4) is predominantly responsible for the metabolism of Alfentanil. TrueAlfentanil undergoes extensive hepatic metabolism that demonstrates extensive interindividual variability False, no variability, but extensive hepaticThe bioavailability of sublingual buprenorphine is similar to that of parenteral buprenorphine TRUE/FALSEEpidural fentanyl undergoes a biphasic absorption pattern TRUE/FALSE ................
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