Diaphragmatic flutter resulting in failure to wean from mechanical ventilator support after coronary artery bypass surgery

Diaphragmatic dysfunction, most commonly elevation of the left hemidiaphragm and/or phrenic nerve paralysis, are well-known complications of coronary artery bypass grafting (CABG). Diaphragmatic flutter (DF) is an easily overlooked breathing pattern characterized by rapid (>40 times/min) involuntary contractions of the diaphragm, at times superimposed on a more normal breathing pattern (dirhythmic breathing). Using respiratory inductive plethysmography, we were able to record this unusual ventilatory pattern in four patients after CABG. All procedures were performed via median sternotomy with topical hypothermia. Sternal complications were present in three cases (instability, dehiscence, infection). DF could not be suppressed by mechanical hyperventilation or patient volition. Weaning was unsuccessful until after DF abated. Diaphragmatic flutter may occur after CABG and should be considered as a cause of failure to wean from mechanical ventilator support in this setting.