Ventilatory Support For Patients With Hypoxaemic Respiratory Failure

Question 1

Discuss the physio Mx for a patient with reduced gas movement

Answer 1

Increase FRC -General positioning, CPAP (NIV), PEEP (MV), deep breathing
Secretion movement - ACBT, huff, cough, assisted cough

Question 2

Describe alternative modes of support for patients in acute respiratory failure

Answer 2

ECMO - extra corporeal membrane oxygenation
NO - nitric oxide (selective pulmonary vasodilator, rebound effect)
HFOV - high frequency oscillating ventilation (low VT, high frequency, gas exchange by convection, good for ARDS)
NAVA - neurally adjusted ventilators assistance (probe to diaphragm which stimulates a breath)

Question 3

Describe how PEEP and CPAP improve gas movement

Answer 3

PEEP and CPAP provide a splinting pressure on the airways at the end of expiration, preventing their closure and subsequent increase in airway resistance. They assist in the re inflation of collapsed alveoli and the prevention of complete emptying of alveoli. This increases FRC and gas exchange surface area as well as the number of alveoli taking part in gas exchange.