Status Asthmaticus and Pregnancy

OVERVIEW

• 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.

STATUS ASTHMATICUS 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 / polyhydramnios?
• does baby impair mothers state/ventilation
• protective ventilation and permissive hypercapnoea -> significant foetal acidosis

Foetus

• viable?
• lung development possible / betamethasone 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 arthrogryposis 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.