Questions
You are called to assess a 38 year old female with respiratory failure in the Emergency Department. This is her first pregnancy and she is 28 weeks pregnant after several attempts at IVF. She is positive for Swine-Origin Influenza Virus (H1N1).
Arterial blood gas on a FiO2 of 0.8 shows:
pH 7.31
pCO2 48 mm Hg
pO2 55 mm Hg Bicarbonate 18 mmol/LEvaluation of the foetal heart reveals significant bradycardia.
a) Outline the specific challenges in this case that distinguish it from a similar illness in a previously healthy 38 year old male.
b) Outline your specific approach to the management of this case.
Answers
a) Outline the specific challenges in this case that distinguish it from a similar illness in a previously healthy 38 year old male.
- Precious pregnancy in older, primiparous patient.
- Known high incidence of morbidity and mortality in mother and foetus with H1N1 Influenza infection with severe CAP.
- Requirement to work closely with specialist obstetric team and rationalising potentially conflicting priorities eg. timing of delivery of foetus.
- Anatomical and Physiological considerations during pregnancy- elevated diaphragm and decreased FRC, decreased chest wall compliance, increased risk of aspiration during intubation, pressure of gravid uterus on IVC (and aorta) decreasing venous return (and increasing afterload) in the supine position.
- Maintaining effective foeto-placental circulation while optimising maternal outcome. Safety of various drugs in pregnancy eg. anti-virals, sedatives.
- History of severe asthma complicating current episode of severe CAP likely to make ventilatory strategy more complex.
- Importance of keeping family members well informed of considerations and likelihood of poor foetal outcome as priority will be given to mother’s survival.
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b) Outline your specific approach to the management of this case.
Immediate-
- Clinical scenario described requires rapid resuscitation.
- Airway- Secure early, rapid sequence induction. Anticipate difficult airway (ensure help and difficult airway equipment available).
- Breathing- Ventilate with protective lung strategy. Example of Settings – SIMV/PC, FiO2-1.0 PC to achieve Tidal Volumes of 6-8ml/kg, Low rate- 6-8/min I:E ratio 1:3-4 to allow adequate expiratory time, PEEP 10-15cm titrated to oxygenation. Close monitoring with regular blood gas evaluation. Tolerate hypercapnia (although not ideal for foetus) if poorly compliant lungs. Position at least 30 degrees head-up to optimise respiratory mechanics. Sedate heavily to minimise oxygen consumption. Neuromuscular blockade if required to facilitate ventilation.
- Circulation- Fluid resuscitate (likely to be volume depleted) to clinical endpoints, vasoconstrictors to maintain perfusion pressure (eg MAP>60mmHg). Assessment of cardiac output if unstable haemodynamics with these measures (eg. echocardiogram, PiCCO, PA catheter, ScVO2)- High cardiac output expected due to pregnancy and infection. Inotropes if cardiac output low. Position slightly left lateral to relieve IVC compression.
- Early specialist obstetric evaluation to determine foetal condition, position of placenta and risk versus benefit of delivery of foetus may need to be considered carefully taking into consideration maternal and foetal factors.
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Pass rate: 54%
CICM Fellowship Short Answer Questions (SAQ)
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