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Interactive effects of corticosteroid and mechanical ventilation on diaphragm muscle function

Catherine S H Sassoon1, Ercheng Zhu, Liwei Fang

  • 1Department of Medicine, VA Long Beach Healthcare System, 5901 East 7th Street, Long Beach, California 90822, USA. csassoon@uci.edu

Muscle & Nerve
|December 21, 2010
PubMed

Insights

High-dose methylprednisolone (MP) combined with assisted mechanical ventilation (AMV) impairs diaphragm function in rabbits. However, MP did not worsen diaphragm dysfunction caused by controlled mechanical ventilation (CMV).

Area of Science:

  • Physiology
  • Pharmacology
  • Critical Care Medicine

Background:

  • Diaphragm dysfunction is a significant concern in mechanically ventilated patients.
  • The impact of corticosteroids, like methylprednisolone, on diaphragm function during mechanical ventilation is not fully understood.
  • Understanding these interactions is crucial for optimizing patient care and ventilator strategies.

Purpose of the Study:

  • To investigate the interactive effects of methylprednisolone (MP) with controlled mechanical ventilation (CMV) and assisted mechanical ventilation (AMV) on diaphragm function.
  • To determine if MP exacerbates or mitigates ventilation-induced diaphragm injury.
  • To elucidate the molecular mechanisms underlying these interactions.

Main Methods:

  • Sedated rabbits were subjected to 2 days of CMV, AMV, or spontaneous breathing (SB) with either intravenous methylprednisolone (60 mg/kg/day) or saline.
  • Diaphragm muscle function (maximal tetanic tension, P(o)), myofibrillar ultrastructure, αII-spectrin, insulin-like growth factor-1 (IGF-1), and MAF-box mRNA were assessed.
  • A control group receiving no intervention was included.

Main Results:

  • CMV significantly reduced P(o), but co-administration with MP did not further decrease it.
  • AMV alone did not impair P(o) compared to SB and controls.
  • Combined MP with AMV or SB substantially decreased P(o) and induced myofibrillar disruption.
  • MP plus CMV, MP plus AMV, or MP plus SB increased αII-spectrin, decreased IGF-1, and increased MAF-box mRNA, indicating muscle injury and atrophy signaling.

Conclusions:

  • Acute, high-dose methylprednisolone can impair diaphragm function, particularly when combined with assisted mechanical ventilation.
  • Methylprednisolone did not exacerbate CMV-induced diaphragm dysfunction in this model.
  • Diaphragm dysfunction induced by MP depends on the mode of mechanical ventilation, highlighting the importance of ventilator settings in corticosteroid-treated patients.

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