Nasal Positive Pressure Ventilation in Patients with Acute Respiratory Failure (4)
This 49-year-old male patient had suffered from severe coronary artery disease for 15 years (two myocardial infarctions, followed by two coronary artery bypass grafts) when he received a heart transplant in 1987 because of left ventricular failure and persistent angina. Two years later, in the context of a cytomegalovirus infection probably induced by his immunosuppressive therapy (cyclosporin A, azathioprine, and prednisone), the patient developed neurologic symptoms; 15 days before admission to the hospital, he mentioned severe pain and dysesthesia in the legs, followed one week later by weakness extending soon to both arms and legs and, finally, rapidly increasing dyspnea. A diagnosis of Guillain-Barr£ syndrome was established, with respiratory muscle involvement; cerebrospinal fluid contained only one mononuclear cell, whereas the protein level was 700 mg^L, the VC was 2,3 L (56 percent of predicted value), and the peak expiratory flow rate (PEFR) was 230 L/min. Arterial blood gas levels were still normal. Plasmaphereses were initiated.
One week later, the VC decreased significantly (Fig 1); and in addition to plasmaphereses, gamma globulins were given (0.4 g/kg of body weight per day during one week). The VC was then increasing, and severe ventilatory insufficiency disappeared, with a VC greater than 2.0 L 15 days after hospitalization. Unfortunately, the VC decreased again very rapidly, down to an alarming value of 0.65 L, and an acute respiratory acidosis and severe dyspnea occurred together, with tachypnea and acute stress reaction (Table 1).
Figure 1. Detailed description of period of acute respiratory failure in patient 1 (illustrative case). IPPV/AC, intermittent positive-pressure ventilation in assist-control mode.
Table 1—Trial cfNPPV in Ptitient 1
|Data||Before NPPV (Spontaneous Breathing)||NPPV, after 15 min|
|Respiratory rate per min||45||0|
|Heart rate per min||158||72|
|Systemic arterial pressure, mm Hg||175/115||120/85|
|Arterial blood gas levels|
|PaC04, kPa (mm Hg)||9.2 (69)||4.5 (38)|
|Pa02, kPa (mm Hg)||6.5 (49)||13.0 (98)|