In this case study Martha received relatively low levels of PEEP and pressure support prior to intubation. What are the potential advantages and disadvantages of increasing these parameters for this patient?

Question

What will be an ideal response?

Answer 1

Suggested response: The amount of non-invasive ventilator support Martha received prior to intubation was relatively low. Morbidly obese patients often suffer from obstructive sleep apnoea and require higher amounts of CPAP/PEEP to manage this condition. Central obesity can also contribute to the cephalic displacement of the diaphragm and subsequent alveolar collapse. High levels of PEEP and upright positioning are often required to prevent atelectasis. A PEEP of 7 cmH2O is most likely suboptimal for the patient described in the case study. Increasing the PEEP, however, can decrease venous return, resulting in a decreased stroke volume, cardiac output and blood pressure. Nursing staff should be vigilant in assessing for clinical signs of haemodyanamic impairment when adjusting PEEP. An arterial swing or an increased pulse pressure variation on the arterial pressure waveform could be a sign of hypovolaemia. A pressure support of 5 cmH2O is often sufficient in patients breathing without an artificial airway. Patients with respiratory distress and an increased work of breathing may benefit from an increased pressure support. In this case study it may also have been beneficial to increase the pressure support to try and manage the patient's hypercarbia and dyspnoea.