chapter 12 pt4 Flashcards
causes of hypoxia
asthma
drowning
airway obstruction
what are the features of severe asthma ?
history of requiring intubation and mechanical ventilation
emergency hospitalisation
increase use of beta blockers
adverse behavioural and psychological :alcohol or drug dependance / non adherence / depression / learning difficulties
causes of cardiac/ respiratory arrest due to asthma ?
1) bronchospasm , mucous pugging - asphyxia
2) hypoxic arrhythmia
3) beta blocker induced arrhythmia , amino-byline
4) electrolyte imbalance
5) dynamic hyperinflation can occur in mechanically ventilated patients - gradual pressure build up - decreased venous return
6) tension pneumothorax occasionally bilateral
initial treatment of severe asthma ?
1) oxygen support , target of 94 percent and above
2) nebuliser salbutamol 5 mg every 15-30 mins
3) add nebuliser ipratropium bromide 500mcg ever 4-6hr if acute or life threatening asthma
4) prednisiloe 40-50mg orally
hydrocortisone 100mg IV 6 hourly
5) single dose of IV magnesium sulphate 2g over 20 min to patient with acute severe asthma
PEF<50 percent
6) consider IV salbutamol 250mcg slowly - when inhaled not possible - patient recievingbag mask ventilation
- if used monitor serum lactate for evidence of toxicity
6)AFTER SENIOR ADVICE
STAT IV aminophyline 5mg /kg over 20 min
followed by IV 500-700mcg / kg/hr
serum theophylline conc below 20mcg/ml
7) beta blockers and steroids can induce hypokalaemia - electrolyte replacement
8) consider tracheal intubation for life threatening asthma for deteriorating peak flow , decreasing conscious level , persisting or worsening hypoxemia
resp acidosis not just pac02 rising
adverse effects of magnesium sulphate ?
flushing , hypotension
measurement for severity of asthma ?
acute severe asthma
PEF 33-50 percent
RR >- 25/min
HR >- 110min
unable to complete sentences
life threatening asthma
PEF <33percent
Sao2 = <92 percent
Po2 <8kpa
arrythmia
altered level of consciousness
silent chest
cyanosis
hypotension
poor respiratory effort
near fatal asthma
raised paC02
how to manage asthma associated arrest
early tracheal intubation - significant risk if gastric inflation and hypoventilation of the lungs when attempting to ventilate a patient sever asthmatic patient WITHOUT gastric tube
recommended resp rate is 10 per min
tidal volume for normal chest rise
CPR may cause dynamic hyperinflation - compressing chest wall and period of disconnecting tracheal tube may help
consider increasing defibrillates energy if first shock if unsuccessful
ALWAYS CONSIDER BILATERAL TENSION PNEUMOTHORAX in asthma - extracorporeal life support
what causes anaphylaxis?
food (nuts)
drugs - peaks in elderly due to poly pharmacy (muscle relaxants , antibiotics ,NSAIDS)
stinging insects
criteria for anaphylaxis ?
sudden onset and rapid progression of symptoms
life threatening / airway / breathing or circulation problem
skin and mucosal change - flushing , urticaria , angioedema / gastrointestinal changes
signs and symptoms of anaphylaxis ?
first features skin and mucosal changes - erythema , urticaria , angiodema (deeper tissues) - eyelids and lips
1) airway swelling / throat and tongue/pharyngeal and laryngeal edema - difficulty breathing and swallowing
2) hoarse voice
3) stridor
4) wheeze
5) cyanosis
6) tachycardia / hypotension
dd of anaphylaxis?
acute severe asthma
inducible laryngeal obstruction - vocal cord obstruction
ACE induced angioedema
panic attack(esp victims of previous anaphylaxis shock)
treatment of anaphylatic cardio resp arrest?
A-E
initially give the highest concentration of oxygen possible using NBM target sp02 94 percent and above
Consider early tracheal intubation - as may exacerbate laryngeal edema
as airway obstruction progresses - SUPRAGLOTTIC AIRWAY DEVICE = I-GEL
lying flat with or without elevating the leg
recovery position if unconscious - pregnant ladies lay on left side of aortavacal compression
sitting position can help the patient breath better
stop the trigger
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ADRENALINE -IM anterolateral middle third of thigh
adult 0.5mcg (0.5ml of 1:1000)
2 doses can be given
alpha agonist - reverse peripheral vasodilator and reduced edema
beta receptor activity - bronchial dilation , increases force of myocardial contraction
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refectory to two doses
establish IV or IO access
seek expert help
rapid iv fluid bolus - children 10ml/kg
adult 500-1000ml
start iv adrenaline (give IM adrenaline every 5 mins until until IV adrenaline has started)
start low dose - 1mg in 100 ml saline
prime and connect with an infusion pump
adult and children 0.1-1ml/kg/hr
continuous monitoring is mandatory = bp , use oximetry and ECG)
(high bp adrenaline overdose
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refectory to adrenaline infusion
add second vasopressor - noradrenaline , metaraminol , vasopressin
nebuliser adrenaline for laryngeal edema 5ml of 1mg per ml (1:1000)
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severe persistant bronchospasm - regular nebs, IV salbutamol or aminophyline
IM adrenaline dosage changes according to age ?
adult and children above 12 -
1mg per ml
0.5ml or 500mcg
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6-12 = 300mcg
6 months to 6years -150mcg
<6 months = 100-150mcg
investigation in cardiac arrest that might confirm anaphylaxis ?
mast cell tryptase - one sample within 2 HOURS no later than 4 HOURS OF SYMPTOM ONSET
ideally 3 timed
initial as soon as feasible after resus started
second sample in 2-4 hours no later than 4
third at 24 hours or convalescence
more than 2ml is preferred
BIGGEST COMPLICATION OF ANPHYLAXIS AND THAT NEEDS TO BE DISCUSSED DURING DISCHARGE
BIPHASIC REACTION
before d/c information given and clear instruction to return to hospital
consider adrenaline auto injector
