E-supplement

Royal Children’s Hospital Melbourne Approach to Management of Acute Lung Injury

  • Conventional ventilation: Tidal volume 6-8 ml/kg, peak pressure<30cm, PEEP 8-10 cm, Fio2 < 0.5-0.6; target SpO2 80-85 adequate in most situations and target pH~7.2 (accept pCO2 60-80 mmHg, if no brain injury)
  • Recruit collapsed alveoli: Use 30 sec inflation +10cm above PEEP; clamp ETT when reconnecting to ventilator
  • Ensure adequate analgesia and sedation with continuous morphine and midazolam infusion.
  • Pressure supported patient triggered mode of ventilation initially; if blood gases poor or ventilator-patient asynchrony, initiate neuromuscular paralysis
  • Early fluid restriction & pharmacological diuresis. Consider hemofiltration to achieve neutral to negative fluid balance
  • Consider trial of nitric oxide for worsening hypoxemia. Echocardiogram to check for pulmonary hypertension, patent foramen ovale and asses right ventricular function
  • Patient specific: Steroids, prone positioning and surfactant therapy
  • If blood gases not in target range with above measures  HFOV

Infant: MAP 5 above MAP for CMV: 16-25, delta-P 30-50 cmH2O, frequency 6-10 Hz, IT 33%

Child: MAP 5 above MAP for CMV: 18-30, delta-P 35-60 cmH2O, frequency 6-8 Hz, IT 33%

Adolescent: MAP 5 above MAP for CMV: 20-35, delta-P 35-70 cmH2O, frequency 4-8 Hz, IT 33%

To improve oxygenation: MAP increased (keeping Fio2 <0.5) while monitoring for overinflation (CXR)

To improve ventilation (lower CO2): Reduce frequency or increase delta-P, maintain leak by deflating ETT cuff

  • Worsening hypoxemia or multi-organ disease despite above  ECMO

If hemodynamically unstable (eg-septic shock & indirect ALI) VA-ECMO with central cannulation preferred for high flow, peripheral V-A for RV dysfunction and RV dilation. In other situations, VV-ECMO targeting saturation >80% whilst changing ventilator to “rest settings”(typically PEEP 10 cmH2O, peak inspiratory pressure <25 cmH2O, rate 8–10 breaths per minute)

  • Other considerations in approach to ALI

Infection: Early BAL (microscopy, gram stain, bacterial and fungal culture, viral PCR and other tests as indicated) plus inflammatory markers (procalcitonin, IT ratio). Antibiotics to cover likely pathogens based on epidemiology, and early consideration of oseltamivir if influenza likely.

Sub-acute phase of illness (improving but still not ready for weaning/extubation): Early mobilisation and sedation breaks to ensure an easier weaning phase, less muscle atrophy, less encephalopathy. Establish an early bowel regimen

Assessment: CT chest generally not warranted, but on occasions can help characterise the fibrosing nature of the lung disease, or bronchiectasis, or bronchiolitis obliterans, or clearly demarcate the lobes involved. Lung biopsy generally not helpful in identifying a treatable problem but may help in confirming futility (fibrosis, loss of architecture, alveolar capillary dysplasia etc..,)

PEEP, positive end-expiratory pressure; MAP, mean airway pressure; IT, inspiratory time; CMV,continuous mandatory ventilation; VA-ECMO, veno-arterial extracorporeal membrane oxygenation; VV-ECMO, veno-venous extracorporeal membrane oxygenation; ETT, endotracheal tube; HFOV, high frequency oscillation ventilation; ALI, Acute lung injury; RV, right ventricle; BAL, Bronchoalveolar lavage; PCR, polymerase chain reaction; IT, immature to total