Tests_B Flashcards
Write correct neurotransmitter
- Pre-ganglionic neurotransmitter for para$ and $
- Postganglionic for $
- Postganglionic for para$
- Ach
- NA
- Ach
Describe the changes in the resp system that take place in the elderly?
Lung elasticity
Elastic recoil
Vital capacity and residuel lung volume
Derc. Lung elasticity:
Incr. in compliance
Total pulm compliance remains the same due to
Fibrocalcification of the thoracic cage - leading
To reduced compliance of chest wall
Loses elastic recoil, this leads to early a/w closure during expiration
Thus closing volume will begin to exceed FRC: (65 yrs)
Lower V/Q ratios. And lower arterial O2 tension
Vital capacity: progressive erosion
Residual Lung volume: increase
Why is it prefered to admin GA to an obese pt with the aid of a ETT and controled ventilation? Only if a/ w can be safely established + need rapid seq induction.
Actually regional is prefered but spinal / epidural doses need to be 75-80% the normal dose.
Lung chest compliance is decreased: (35%)
- decr size of thorax, due to big abdomen -
diaphram splitting
- heavy chest wall
- all lead to incr in work of breathing
Decrease in FRC (normaly dcr in obesity)
- lowered lung chest compliance further incr. work of breathing
- decr in arterial oxygenation - low VQ units
- effective mx of a/w and preox very NB due to pt becoming hypoxic early due to incr. oxy demand
- effect of IAA
OSA more common in obese pts. ( obstructive slaap apnoea)
Sedative and anelgesic drugs may compromise
A/w - they need to sleep on added oxy in hosp.
Review textbook p.149
62 year old man weighs 80 kgs
He must undergo a hemicolectomy that will last 3 hours.
He is NPO since 22h00 and the procedure is scheduled for 8h00.
He had bowel prep.
Expected bloodloss is 500ml.
What is his intraoperative fluid req?
Preoperative
1-1.5 ml/kg/hr NPO
Normal saline= 360ml isotonic crystalloid
Maintenance: same as above
Third space loss: 1-6ml/kg/hr= 240-640ml Isotonic crystalloid (more because of large surg)
Blood loss:
75ml/kg x 80 = 60000ml, thus
List 5 drugs or classes that should be avoided in asthmatic?
Beta blocker NSAIDs Aspirine Adenosine Atracurium, Mivacurium
A pt with IHD must receive GA:
Which heamodynamic changes has been shown to be a specific risk?
Why?
Which drug will reduce risk of acute ischeamia?
Tachycardia.
During a tachy, diastolic time is decreased
Coronary flow is time dependant.
With decreased flow (stenosis)
Ischeamia and necrosis may result
Beta adrenergic receptor blockers
Clinical symptoms and signs of Malignant Hyperthermia?
THAT TRIM
Non specific - THAT Tachycardia HyperK Acidosis Tachypnoea
Specific - TRIM Temp incr Rhabdomyolysis Increased CO2 production Muscle rigidity
Early signs:
Masseter muscle spasm and other muscles
Tachycardia and HTN
One of the first signs if unexplained
PaCO2 incr production and
Metabolic acidosis. (Both due to incr
metabolism) and stimulate symp system.
Dysrythmia (hyperkaleamia)
Hyperthermia (exceed 43)
Hypercapnoea and tachypnoea
Late Warm to touch Cyanosis Metabolic acidosis - incr Peaked t waves - hyperkaleamia Darker blood
What is the drug of choice for MH?
Dantroline sodium
Why will elderly pts require reduced dosages of the following drugs?
Propofol
Opioid
Propofol:
Hepatic function declined, decr in clearance
And prolonged duration of action
Opioid:
Slow arm- brain circulation - give slowly
Longer half life and are more sensitive to effects
Morphine:
- Optimal route for morphine?
- Why would you use this route?
- What dose would you use for this route?
- What end point would be used to know when to stop admin the initial dose?
- IV
- Rapid onset of effect
- 1-2mg increments IVI every 5 min
OR 0.15mg/kg imi - Tolerance to pain
What are the sfx of morphine?
GIT : NVC
Drowsiness, sedation
Resp depression
CVS - hypoT
Name an alternative technique to achieve anelgesia other that IV morphine?
Patient controlled anelgesia (PCA)
Epidural
Femoral nerve block
Ketamine low dose
List the problems you can anticipate during an anesthetic for post-tonsillectomy bleeding?
Hypovoleamia Aneamia Swallowed blood and full stomach Oedema of a/w structures Lack of cooperation for LLposition RSI with cricoid pressure alternative Hypothermia. (Because of fluid rescuss)
Explain the concept of central venous pressure and how it is measured?
Used to:
Measure Right heart function
And intravascular blood volume
How it works:
Uses a manometer filled with IV fluid
Attached to central venous catheter
Placed into SVC (neck veins, arm, groin)
Electronic transducer may give continues CVP and waveforms.
What is measure by a capnograph and what is the importance of it in GA?
Measure End tidal CO2
Monitoring intubation (correct placement) Bronchospasm, rebreathing and circulatory collapse can be dx. NB
T/ F:
- Ethanol is used as an antidote to bothe methanol and ethelyne glycol poisoning.
- Toxic dose of salicylates are known to cause resp depression.
- Oral acetylcysteine is effective in the Rx of paracetemol poisoning.
- Major toxic effect of organophosphate poisoning is due to stimulation of the nicotinic cholinergic receptors.
- Effects of cocaine is due to direct stimulation of adrenergic receptors.
- Ketamine, a dissociative anesthetic agent, has similar effects to that of phynocyclidine (angel dust)
- Ecstasy (MDMA) is a hallucinogenic amphetamine.
- Methylamphetamine is also known as TIK
- Overdose with phenothiazine like agent cause EPSE.
- Resp failure is the most common death is scorpionism
- The toxic venom of cape cobra venom causes a curare like effect.
- Paracetamol is primarily a nephrotoxic agent in overdose.
1. 2. 3. False 4. True 5. 6. 7. True 8. True 9. 10. True 11. 12. False
What is absorbtion atelectasis?
By raising O2 content in alveolus the Hb molecules now have sufficient oxygen.
BUT nitrogen is being lost (normally 80% of normal alveolar volume)
Nitrogen is insoluble and remains in alveolus once oxygen removed, thus acting as structure to keep alveolus open.
By filling lung with 100% oxygen you remove nitrogen and as oxygen is removed the alveolus becomes “pap” - decreasing volume.
This aggrevates VQ pathology
List chieve toxic effects/ mechanism of:
- Cape cobra
- Boomslang
- Puff adder
- Button/ widow spider
- Parabuthus scorpion
- Neurotoxic - post synaptic adrenergic receptor
- Heamtotoxic - prothrombin and facto X affected
Bleeding - Neurotoxic - presynaptic peripheral nerve
endings, massive neurotransmitter release - Neurotoxic - Na channel depolarizor
Define osmolality?
What is the osmolality of the folowing pt:
Formula
Measure of the osmoles of a solute per kg solvent.
2Na + urea+ glucose
What is a third space loss? Review
At what rate must it be replaced?
Fluid loss due to oedoema or transcellulR fluid displacement. Thus cannot enter vascular compartment due to high Na content in injured area.
1-6ml/kg/hr
Name factors that can cause generalized tissue oedema?
Oncotic pressure decr. (Albumin)
Hydrostatic pressure increase. (HyperT)
Increase in permeability of membrane
Capp endothelial damage. (Inflammation)
T/F:
1. Sellicks manouvre is posterior pressure on the thyroid cartilage during the process of RSI, to prevent regurgitation in a pt with a full stomach.
- Inheritance of abnormal enz which is responsible for syx apnoea is autosomal dominant?
- ETT with internal diameter of 6.5mm would be correct for a 6yr
- A morbidly obese pt is not in danger of aspiration of stomach content, provided he/she has not taken anything orally for atleast 6 hours.
- Normal neonate will become hypoxic more rapidly after onset of apnoea than a normal adult.
- False - cricoid pressure
- True
- False (age /4 + 4)
- False
- True
What is the commonest blood gas abnormality seen ass with inadequate FgF when using a non- CO2 absorbant circuit?
Hypercapnia
Name 3 groups of effector organs predominantly influenced by the ANS?
Which 2 substances produced by adrenal medulla - name the one which is secreted in highest quantity in adult first
Heart, smooth muscle and glands
Adrenalin
Noradrenaline
Review breathing patterns.
Spontaneous
IPPV
IPPV and PEEP
CPAP
Explain how ill-considered ventilation can cause pneumathoracis (baro or volume trauma)?
Alveoli exhibit interdependance - pressure is distributed amongst them (they dont burts due to pressure)
Rupture of alveoli into the bronchovascular bundle - leads to interstitial oedoema, not the pleura.
Complications of alveoli rupture into bronchovascular sheath?
Interstitual emphysema Pneumothorax Pneumopericardium Pneumomediastinum Subcut emphysema
What are the CI to thiopentane?
Porphyria
CVS (tachycardia undesired -IHD and HTN)
Asthma
List 3 local blocks where adrenaline is CI?
Penis, tip of nose
Biers block
Unstable angina pectoris
Uncontroled HTN
5 advantages of effective pain mx?
Reduces suffering Resp - increase wall compliance CVS - oxygen comsumption less Coagulation (less adverse events) Immunity improved Prevent chronic pain Saves money
What are the 3 components of blanced anesthesia?
Anesthesia - Hypnosis
Anelgesia. - pain relief
muscle relaxation - curarization
Name structure that needle transverses during a lumbar puncture, to aspirate CSF?
Skin Subcut tissue Supraspinous ligament Interspinous ligament Ligamentum flavum Epidural space Dura mater Arachnoid mater
What is the importance of the ligamentum flavum during placement of the local anesthetic into the epidural space?
Epidural space is identified by the needle passage through an area of high resistance (ligamentum flavum) into th low- resistance epidural space.
What effect will hypoxia have on the heart rate of the neonate?
Bradycardia
Describe the pathophysiology of the aspiration of acidic stomach contents?
Aspirated fluid or acid spreads to the lung periphery within seconds (lavage does not help)
Surfactant loss leads to decr. In compliance
Inflammation leads to endothelial damage and incr. alveolar permeability
Fluid filled alveoli - leading to
Hypoxia
Pulmonary oedema
Stiff lungs
What is diffusion hypoxia?
Same mechanism as aspiration
T/F:
1. ET intubation is prefered during CPR.
2. During effective CPR, CO is normal.
3. Open cardiac massage is better that external cardiac.
4. During VF intial defib is at 5Joules/ kg
5. Capnograph reflects CO
6 . Capnograph reflects lung bloodflow.
7. Atropine is given in asystole
8. Bloodflow during CPR is the result of compression of heart bw the sternum an vertebrea only.
9. Ventilation of lungs and compression of chest during cardiopulmonary rescuss should not be done At the same time.
- True
- False
- True
- False
- False
- True
- False
- False
List all methods you can to prevent aspiration of stomach content into lungs?
- Prevent
- Prevent further aspiration
- Oxygenation
- Remove trachebronchial material/ suction
- Symptomatic supportive Rx
1. Reduce stomach volume Promote stomach emptying Stomach pH>2.5 Stomach oesophagus: Barries pressure= LESP - intragastric pressure Laryngeal reflex depressed: maintain protective reflex ID at risk pt RSI
- Head down (lateral position of a/w easy t mntn)
Suction pharynx
RSI
Intubate trachea - 100% o2 initially, later as needed to keep sats > 90%
PEEP>= 5cm H2O to maintain alveolar volume
Preventing alveolar flooding
IPPV because lungs are stuff - Suction trachea, DONT LAVAGE
Bronchoscopy if particulate matter - Rx: bronchospasm
NO routine AB initially (only w infection)
NO routine steroids
ICU, clinical evaluation, CXR, blood gasses
List safe drugs to use in PORPHYRIA
- Induction agent
- Muscle relaxant
- Maintenace of anesthesia
- Reversal of muscular relaxation
- Intra and post op pain
- Propofol
- Succinylcoline, alcuronium
- Sevoflurane
- Neostigmine
- Morphine
Macs for. HIESDN. Review lecture
- Halothane
- Isoflurane
- Enflurane
- Seveflurane
- Desflurane
- n2O
- 0.74
- 1.15
- 1.23
- 1.85
- 7.25
- 101
Define severe sepsis?
SIRS + proven infection + MOD
What differentiates severe sepsis from septic shock?
4 practical points that you can use to initially improve survival in septic shock?
Why is a pt in severe sepsis or septic shock at risk for resp failure?
The repsonse to IV fluids
Goal is to - maximise DO2 1. = CO x Oxygen content (Hb) 2. Requires 30% above physiological values Remove cause Support other organs - esp ventilation Steroids (only poor responders) Anti mediaters Heparin / activated protein C
ARDS
Basic preop evaluation of a pt aimed at ID potential problems with intubation? Face Mouth Neck Thoracoabdominal abnormalities Age Gender Other
Face: Trauma, deformity, stridor, hoarseness, mandible Mouth Macroglossia, protruding teeth, mallampati 3and4 Neck Short and thick Decr. ROM (arthritis, disk disease, spondylitis) Fracture (subluxation) Obvious trauma Thoracoabdominal abnormalities Kyphoscoliosis Prominent chest/ large breasts Morbid obese Term/ near term pregnancy Age - bw 40-59 Gender - male Other Snoring / sleep apnoea syndrome
Define the following:
1.Partial pressure of gas
2. Tension of a gas in liquid
3. Bloodgas partition coefficient of anes.gas
4. Rank order of their blood partition coef.
Halothane, N2O , Isoflurane
- the pressure exerted by a gas in a mixture, which is the pressure the gas would exert if it alone were in the container.
- Partial pressure of gas that would be in equilibrium with it
- The ratio of the amount of a substance at equilibrium which is defined in one phase compared with another - the 2 phase being of equal vol
- Lowest to highest
N2O, Isofluran, Halothane
Take note that the higher MAC is the lower partitioning coef
Name the 2 stimuli which can stimulate the ocular cardiac reflex during opthalmological surgery?
Pressure on the eyeball
Traction on the extraocular muscles
What will the oculo cardiac reflex do to the pulse rate?
Decrease it
Name the efferent and afferent limb of the oculo cardiac reflex?
What drug is used to block this reflex?
Trigeminal
Vagus
Atropine / glycopurylate
T/F:
- Suxamthonium cause depolirization of the postsynaptic membrane of the NMJ.
- Sux and ACh are both hydrolyzed by pseudocholinesterase
- Sux is the only muscle relaxant in use that has a very short onset of action
- Sux will cause a rise in serum K of 4-8mmol/l in a pt with kidney failure.
- Pancuronium will cause a rise in pulse rate and BP
- True
- False
3. - False
- True
What is the clinical picture of a berg adder bite?
Local oedema Opthalmoplegia Anosmia HypoNa Resp failure
ETT sizes for children Prem Neonate - 6mo 6mo - 1 yr 1 - 2 years Beyond 2
3.0
3.0- 3.5
3.5-4.0
4.0-4.5
Age/4+4
Uncuffed
Effect of CO poison?
OHEC left shift - thus oxygen carrying capacity
Hypoxia at tissues
Cytochrome enz bound - thus cannot oxidize
CVS - myocardial ischeamia and vasodilation
Direct effect on vascular SM = hypoT
For CO poisoning what test will you do and what will you see?
Low sats at normal partial pressures of O2
On blood gas
On which organs will the long term effects of CO poisoning be seem?
How will you mx such a pt?
Brain - neuro damage
Heart - myocardial infarction
100% oxygen - increase dissociation of CO-Hb complex
- tigh fitting mask and high flow oxygen
Hyperbaric oxygen therapy :
- unconscious pt
- neuro/ psych features
- COHb concentrations > 20%
Supportive care:
- cardiac monitoring
- Rx of cardiac dysrythmias
- correction of acidbase and electrolyte abnormalities
Give the chemical rxn for the absorbtion of CO2 by soda lime?
CO2 + H2O = H2 CO3
H2CO3 + 2NaOH = Na2CO3 + 2H2O + heat
Na2CO3 + Ca(OH)2 = CaCO3 + 2NaOH
