H1N1 and Pregnancy
16/2/11
SPECIFIC CHALLENGES
- known high incidence of morbidity and mortality in mother and foetus in H1N1 infection and
severe community acquired pneumonia.
- multidisciplinary team approach: O&G, NICU, anaesthetics, ICU
- planned delivery of foetus (although the teams may have conflicting interests)
- 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: pneumothorax, tension, cardiac
arrest, increased airway pressures, watch intrinsic PEEP, high pressures may reflect raised
intra-abdominal pressures.
- importance of keeping family members well informed of considerations and likelihood of
possible poor foetal outcome as priority will be given to mother’s survival.
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 respiratory failure– 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
- safety of various drugs in pregnancy (antivirals, sedatives)
Foetus
- viable?
- lung development possible/bethametasone considered?
- effect of medication given to mother:
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Steroids – potential malformations in the fetus if used in the first trimester – cleft lip
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
Jeremy Fernando (2011)
MANAGEMENT
Resuscitate
A: secure early, RSI, anticipate that it may be difficult and prepare adequately including
calling for help
B: head up, protective lung strategy, but limiting hypercapnoea if possible (SIMV, FiO2 1.0,
TV 6-7mL/kg, low rate, I:E 1 to 3, PEEP 10-15cmH2O titrated to oxygenation, paralyse)
C: fluid resuscitate to clinical endpoints, invasive monitoring, vasoactive agents to maintain
MAP > 60mmHg, may require Q monitoring, left lateral position
Acid-base and Electrolytes
- respiratory acidosis -> manipulation of ventilation
- metabolic acidosis -> treatment of sepsis
Specific Therapy
-
oseltamivir
IV antibiotics to cover possible superinfection
steroids for baby
planned triggers for delivery -> may require it urgently
consideration for adjuncts: iNO, HFOV, (prone and ECMO contraindicated)
monitoring for pulmonary and extra-pulmonary complications
Jeremy Fernando (2011)