GA of the critical patient Flashcards
What should be done before GA on a critical patient?
Correct dehydration, hypovolaemia, BP, elctrolyte abnormalities
Ideally at least 2 catheters- ideally then place an arterial one once asleep
Aside from analgesia, what are some other useful properties of lidocaine?
Retard the effects of compromised viscera, reperfusion injury, venricular arrhythmias
Due to free radical scavenging abilities, analgesic effects, antiarrhythmic properties
WHat effects can anticholinergic agents (atropine/ glycopyrolate) have?
May make secretions more viscous
Increase anatomic dead space
Increase HR
Increase myocardial work and 02 consumption
What affects may dissociative agens (ketamine) have?
Salivation
Increase HR/ ICP/ intraoccular pressure
Analgesia
Renal elimination in cats
What effects can benzodiazepines have?
decrease other drug dosages
mild sedation and muscle relaxation
anticonvulsant
not analgesic
What effects can propofol have
rapid acting, short duration resp depression decreased ICP IOP caution with volume depletion or CV compromise, can be significant depression Peripheral vasodilation myocardial depressant heinz body anaemia in cats
When are arrythmias more prevalent during a GA?
Splenic disease
GDV
septic peritonitis
hypoxia
What levels should you act on BP?
< 60 mean, <90 systolic
What are the steps for low BP during GA?
decrease inhalational anaesthetic
fluid bolus
CRI of dobutamine or dopamine - monitor for tachycardia
If still low then inhalational GA may have to be swapped and switched to CRI
What id the use of monitoring lactate?
Indicator of poor perfusion as is a product of anaerobic respiration
Best to assess serial lactates to get an impression of lactate clearance - good lactate clearance suggests improving perfusion and better prognosis
How can lactate help give a prognosis for GVD?
Over 6 initially suggestive of gastric necrosis
WHat is the imporatance of a ventricular arrhythmia?
Normally a non perfusing rhythm
Can deteriorate to ventricular fibrillation
Tx when BP low, multiform complexes, R on T phenomenom
Tx with lidocaine
WHat are the types of capnography?
More common = side stream, delay of 1-2 sec
Less common = main stream, more expensive, instant, less prone to errors d/t condensation
What are the stages of a capnograph wave?
A-B = inspiratory pause B-C start of exhalation C-D alveolar plateau D - end tidal CO2 D-E start of inhalation
What happens in hypo or hyperventilation?
Hypoventilation - >45mmHg - vasodilation, hypotension, poor perfusion
Hyperventilation - <35mmHg, vasoconstriction, poor perfusion, resp alkalosis
What does it mean if the inspiratory flow is not O?
Leak or fresh gas flow not high enough
What does it mean if there is no alveolar plateau?
Obstruction (e.g. mucous in tube) or bronchoconstriction
What can it mean related to the heart if there is low CO2
Poor cardiac output - can suggest impending crash
How do you calculate BP?
BP = CO x vascular resistance
Compare oscillometric and doppler BP measures
Doppler - systolic, good for small patients
can under estimate BP when low, or over estimate it when high
Oscillometric - Systolic, mean, diastolic
>5kg
Compare warm and cold shock
Cold - classic shock signs, due to low volume
Warm - low vascular tone, when crt time v quick, injected mm
What SPO2 should you aim for in a hypoxaemic patient?
90-95%
What is the importance of glucosuria with normoglycaemia?
Suggestive of renal tubular injury
This can be due to ischaemia, toxins, drugs
Can be present days before azotaemia
