Tonsillectomy & paediatric respiratory Flashcards
What are the most common indications for adenotonsillectomy? What’s the most common of those?
Recurrent infection, airway obstruction resulting in sleep-disordered breathing/OSA
Now most common indication= OSA (indication for >75% of adenotonsillectomies)
What are the key issues making airway management for adenotonsillectomy particularly challenging?
-SHARED AIRWAY by anaes & surgeon; must protect from blood & secretions
-incidence of laryngospasm higher than during other surg procedures
-chn for whom the surgical indication= OSA are @ particularly HIGH RISK of significant postop resp complications
What are particular areas of focus in the pre-anaes evaluation of a child for tonsillectomy?
Hx of sleep-disordered breathing
bleeding risk
recent URTI
What is the risk with undergoing GA with a current or recent URTI & why?
Airway hyperreactivity= the risk & the risk of this decreases over time with a URTI- some sources show increased reactivity for up to 4/52 after URTI
Incr risk of periop resp adverse events if GA & current/recent RTI eg. laryngospasm, bronchospasm, atelectasis, coughing, airway obstruction (2-7x, intubation incr this 11x), hypoxia (intra- & post-op), stridor, breath holding.
May incr admission rates & cost of prop hospitalisation.
What are the most common causes of paediatric Periop cardiac arrests?
Cardiovascular causes
Respiratory causes (of which laryngospasm= the most likely to cause Resp-induced cardiac arrest)
What’s a simple way of considering risk of proceeding vs deferring in the setting of current/recent URTI?
C O L D S score:
current symptoms (mild-severe)
onset (>4/52= 1 point, 2-4 2 pts, <2/52= 5 pts)
lung disease
airway device planned (none/facemask, LMA, ETT)
airway surg? (no, minor (eg. T&A), major (eg. cleft))
hard signs= lethargy/unwell, febrile >38, productive cough, purulent green/yellow nasal discharge, active chest infection (eg. creps on lungs), if need to intubate, age <1
softer signs= degree of instrumentation of airway, passive smoking @ home, reliability of parents w postop care
UNWELL CHILD, DEFER 4-6wks
How much more common is laryngospasm in a pt with or without active URTI?
2x as common if current URTI
In ex-prem infants, what type of infection, @ the time of anaesthesia, is ass’d w incr risk of unplanned postop ICU admission?
RSV- so it MAY be useful to rule out RSV prior to elective procedures
For how long after a URTI should elective surgery be deferred?
2-4/52
For how long may airway reactivity persist following an URTI?
6/52
What’s the pre-op optimisation med for a pt with asthma/recurrent wheeze OR with a recent/current URTI but surg must proceed (3 classes)? dose?
AND what should all pts with a URI who are old enough use postop?
- short-acting B-agonist: salbutamol neb 2.5mg if <20kg, 5mg if >20kg, or via MDI w spacer (2-8 puffs)
- anti-sialagogue: glycol 4mcg/kg
- if significant rhinorrhoea, a nasal decongestant: oxymetazoline (sudafed) spray, 0.05%, max 2 sprays/nostril IF >=6yo, if 1-6yo, gentle half-spray/nostril, NOT to infants
All should use incentive spirometry
What’s the drug & dose as an anti-sialagogue for a child @ high risk of periop resp adverse events?
IV glyco, 4mcg/kg
What’s another potential measure for chn with signifiant bronchial secretions?
chest physio, encouraging cough, postop incentive spirometry
Should periop systemic glucocorticoids be given to pts w URTI?
Only for those w poorly controlled asthma
If a pt presents with partially controlled asthma could consider periop ICS in consultation w resp physician; systemic steroids if severe uncontrolled asthma in consultation w pulm physician (pred 1mg/kg (up to 50mg) for 3-10 days) or hydrocortisone 4mg/kg (max 100mg) every 6 hrs)
What premed should not be used with a URTI? why? what’s the best approach preop for such pts?
midaz or other BZD- delays wakening, prolong the excitatory phase of emergence from anaesthesia, reduce FRC & alter resp mechanics- ass’d w incr risk desats & airway obstruction & DON’T reduce laryngospasm or bronchospasm; they INCR RISK FOR POSTOP RESP COMPLICATIONS. Best to use distraction/parental presence & avoid premeds in pts w URI.
What are some considerations for the conduct of anaesthesia in a child w URTI where surg must proceed?
RA where possible
avoid sedative premedication
if GA, pre-op salbutamol, anti-sialagogue +/- nasal decongestant
use propofol vs sevo (less impairment of ciliary clearance of bronchial/tracheal secretions)
use lung-protective mech vent strategies (low TVs, PEEP, prol I:E ratio if necessary) BUT if bronchospasm develops, reduce air trapping via reduction in MV & I:E ratio
Use LMA vs ETT where possible (lower risk bronchospasm w LMA) but in young chn ETT may be safer. If an ETT used in an asthmatic, cuffed better (achieve higher peak airway pressures, less risk broncho or laryngospasm)
If intubating, IV better than inhalation induction for chn @ risk PRAEs (APRICOT study- inhalation induction ass’d w sig higher risk severe resp critical events), use a sufficiently large dose of induction agent & use a NMBD (less risk of PRAEs in chn w asthma)
Ventilatory strategy: lower MV by reducing rate & TV, low but some PEEP, adjust I:E ratio to ensure exp flows returning as close to baseline as possible
intermittent disconnection from ventilator may help if pt developing high Pit & reduced venous return
Use most experienced operator
What type of drug is oxymetaozline?
alpha agonist, promotes nasal VC hence decongestion
What is asthma?
a chronic inflammatory lung condition characterised by cough/wheeze/dyspnoea & chest tightness, partially or completely reversible airway narrowing & increased airway responsiveness to a variety of stimuli.
When are the most common points for wheezing during GA?
induction after endotracheal intubation
Whats the goal outcome of preop Ax of pts w asthma?
Reduction in risk of periop resp adverse events through optimising therapy
What factors on Hx are vital in the preop Ax of a pt w asthma or to screen a pt (esp child) for risk?
Risk screening:
FHx allergies/asthma/atopy
child Hx allergies atopy/rhinorrhoea/eczema/wheeze
Passive or active smoking
questions if Hx asthma:
Type & level of control
Triggering factors
Frequency & type of medication
Last flare, meds (eg. most recent use of glucocorticoids)
Hx of ED visits/hospitalisations & intubations
Recent URTI/sinus infection/nocturnal cough/fever
Baseline & current peak exp flow or FEV1
If ANY features suggesting partial control, the pt should be referred to primary care physician/specialist for optimisation prior to elective surgery
What are the types of asthma?
mild intermittent: symptoms mild & <2 days/week or <2 nights/month, FEV1 >80% pred
mild persistent: symptoms >2x/week but not daily, up to 4 nights/month, FEV1 >=80% pred
moderate persistent: symptoms daily & at least one night per week, may limit some daily activities, FEV1 >60-<80%, FEV1/FVC reduced by <5%
severe persistent: symptoms occur several times per day & most nights & ADLs extremely limited, FEV1 <60%, FEV1/FVC reduced by >5%
What are some features of asthma suggesting partial control? what is the Dx of poor control?
symptoms on waking
symptoms OR requiring use of reliever >2x/week
nocturnal symptoms
impairment to ADLs
days off work due to asthma
FEV1 <80% pred or PB
(any of the above= partial control, 3 or more features of partial control in one week= uncontrolled)
asthma attack (none=good control, partly controlled= annual, uncontrolled=weekly).
What’s a consideration for pts who have taken glucocorticoids for asthma?
May have HPA axis suppression; if they’ve taken >5mg/day pred for >3/52 in the past year, should have a stress dose of glucocorticoid prior to induction of anaesthesia.
From what age can children do PFTs/peak flow?
5
Are there any asthma medications that should not be taken up to & including the day of surgery? why?
only theophylline, which may cause cardiac arrhythmias. continue all others up to & including day of surgery as it reduces risk postop pulm complications.
How long before OT should children w asthma receive SABA?
20-30mins, neb (2.5mg salbutamol if <20kg, 5mg if >20kg) or MDI 2-8 puffs)
Have systemic glucocorticoids been shown to increase postop wound infections or delay wound healing?
no
What may be the benefit of giving preop salbutamol to children undergoing adenotonsillectomy who have a wheeze & are at increased risk for PRAEs (eg. mod-severe OSA, recent URTI <2/52, Hx asthma/eczema/hayfever/exposure to passive smoke)?
Reduced PRAEs
If any premed used for an asthmatic child, which ones?
clonidine (2.5mch/kg PO) or dexmed (intranasal 2mcg/kg), as they may blunt reflex BC
In addition to the list, what are some factors increasing the risk of bronchospasm during surg/anaesthesia?
histamine release or allergic reaction to meds given
vagal stimulus w surg (eg. pneumoperitoneum)
What are some benefits of using a cuffed ETT (w pressure monitored)?
less risk broncho or laryngospasm, less sore throat or hoarse voice, less cough
Should topical lignocaine be used prior to ETT in chn?
not without the use of NMBDs as it initially causes bronchoconstriction in pts w asthma, may risk cough & laryngospasm, it increases the risk of desaturation if used without NMBD
Might lignocaine help w risk of bronchial hyperactivity in adults?
Yes- 1mg/kg IV & 5mg in saline nebulised attenuate bronchial hyperactivity, including in pts w asthma
Is ketamine, in addition to standard asthma treatment, of benefit to chn w acute asthma exam in the ED?
No
