Bilateral phrenic nerve block as an effective means of controlling inspiratory efforts in a COVID-19 patient

Bilateral phrenic nerve block to reduce hazardous respiratory drive in a mechanically ventilated patient with COVID-19-A case report

Key Clinical Message

Forced inspiration during mechanical ventilation risks self-inflicted lung injury. However, controlling it with sedation or paralysis may cause polyneuropathy and myopathy. We tested bilateral phrenic nerve paralysis with local anesthetic in a patient, showing reduced inspiratory force. This offers an alternative to drug-induced muscle paralysis.

Abstract

Mechanical ventilation, although a life-saving measure, can also pose a risk of causing lung injury known as "ventilator-induced lung injury" or VILI. Patients undergoing mechanical ventilation sometimes exhibit heightened inspiratory efforts, wherein the negative pressure generated by the respiratory muscles adds to the positive pressure generated by the ventilator. This combination of high pressures can lead to a syndrome similar to VILI, referred to as "patient self-inflicted lung injury" or P-SILI. Prevention of P-SILI requires the administration of deep sedation and muscle paralysis to the patients, but both these measures can have undesired effects on their health. In this case report, we demonstrate the effect of a bilateral phrenic nerve block aiming to reduce excessive inspiratory respiratory efforts in a patient suffering from COVID-19 pneumonitis.

Pneumomediastinum as patient self-inflicted lung injury in patients with acute respiratory distress syndrome due to COVID-19: a case series

Background

In patients with coronavirus disease (COVID-19) due to severe acute respiratory syndrome coronavirus 2 infection, pneumomediastinum has been increasingly reported in cases of noninvasive oxygen therapy, including high-flow nasal cannula, and invasive mechanical ventilation. However, its pathogenesis is still not understood.

Case Presentation

We report two cases of pneumomediastinum in acute respiratory distress syndrome (ARDS) caused by COVID-19. In both cases, control of spontaneous breathing with neuromuscular blocking agents resulted in resolution of pneumoperitoneum.

Conclusion

The improvement of pneumomediastinum with control of spontaneous breathing suggested patient self-inflicted lung injury as a possible mechanism in this case series. In ARDS cases with pneumomediastinum, in addition to controlling plateau pressure with conventional lung protective ventilation, spontaneous breathing should be controlled if the patient's inspiratory effort is suspected to be strong.