Status Asthmaticus and Pregnancy
8/10/10
- dangerous situation
- 2 patients
- complex
- need to call for help early
- pregnancy related issues are dependent on stage of pregnancy
-> first trimester: avoidance of teratogenicity
-> third trimester: management physiology of pregnancy
- requires rapid assessment, resuscitation, treatment and consideration of best disposition for mother and baby.
ASTHMA Management
- definition = acute asthma that is refractory to medical management.
- medical treatment:
-> hydration
-> beta agonists (inhaled and iv)
-> steroids
-> Mg - consider foetus
- non-invasive ventilatory support: CPAP and BIPAP
- indication for intubation: if respiratory failure, hypoxaemia, hypercapnia, exhaustion.
- high risk intubation: aspiration, difficult airway, narrow airway, worsening acidosis, cardiac arrest.
- difficulties ventilation and complication of ventilation: hyperinflation, pneumothorax, tension, cardiac arrest, increased airway pressures, need long expiratory time, watch intrinsic PEEP, high pressures may reflect raised intra-abdominal pressures.
Pregnancy related issues
- call for help early
- multidisciplinary team approach: O&G, NICU, anaesthetics, ICU
Mother
- physiologic changes of pregnancy: respiratory/cardiovascular, aortocaval compression syndrome.
- need to be aware of the changes in blood gas reference values.
- need to position carefully -> ideally left lateral position.
- pregnancy can worsen asthma – pulmonary congestion, reflux disease, low FRC
- reduced respiratory reserve - > decompensation can be rapid
- hx of pregnancy: gestational age, singleton?, size of baby / polyhydramnious?
- does baby impair mothers state/ventilation
- protective ventilation and permissive hypercapnoea -> significant foetal acidosis
Foetus
- viable?
- lung development possible / bethametasone considered?
- effect of medication given to mother:
-> Steroids – potential malformations in the first trimester (cleft lip)
-> Beta 2 agonists – risk of tocolytic pulmonary oedema - delay in onset of labour
-> Benzodiazepines – floppy infant syndrome
-> Opiates - fetal respiratory depression
-> Prolonged paralysis – risk of arthrogyphosis in the fetus
- maternal hypercapnia – reduces uteroplacental blood flow + shifts oxyHb dissociation curve in the fetus to the right -> thus impairing fetal oxygenation – fetal monitoring essential
- long term maternal hypoxia associated with IUGR
ENVIRONMENT
- adequate staff for moving of patient
- monitoring of baby (continuous CTG may be indicated)
- develop a plan for if mother or baby deteriorate.
Jeremy Fernando (2011)