Influenza and Pregnancy
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 / polyhydramnios?
- 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/betamethasone considered?
- effect of medication given to mother:
-> 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 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
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
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.
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