title: Volume-controlled versus biphasic positive airway pressure ventilation in leukopenic patients with severe respiratory failure.
abstract: OBJECTIVE
  To study comparatively the effects of volume-controlled vs. biphasic positive airway pressure mechanical ventilation on respiratory mechanics and oxygenation in leukopenic patients with severe respiratory failure.
  
  
  METHODS
  Prospective, comparative study.
  
  
  METHODS
  Medical intensive care unit of a university hospital.
  
  
  METHODS
  Leukopenic (<1000 leukocytes/microliter) patients (n=20) after cytoreductive chemotherapy requiring mechanical ventilation for severe respiratory failure (Murray score of > 2.5).
  
  
  METHODS
  Patients were assigned in a consecutive, alternating manner to receive either volume-controlled or biphasic positive airway pressure mechanical ventilation, starting within 12 to 24 hrs after endotracheal intubation.
  
  
  RESULTS
  Tidal volume, inspiratory flow, peak inspiratory and positive end-expiratory pressures, FIO2, and arterial blood gas analyses were recorded hourly for a study period of 48 hrs. Biphasic positive airway pressure ventilation was associated with a significant reduction in peak inspiratory pressure (mean differences at 24, 36, and 48 hrs: 4.4, 3.4, and 4.2 cm H2O; p = .024, .019, and .013, respectively) and positive end-expiratory pressures (mean differences at 24, 36, and 48 hrs: 1.6, 1.4, and 1.5 cm H20; p = .023, .024, and .023, respectively) at significantly lower FIO2 (mean differences at 12, 24, 36, and 48 hrs; p = .007, .015, .016, and .011, respectively). PaO2/FIO2 ratios and CO2 removal were similar under ventilatory conditions.
  
  
  CONCLUSIONS
  Biphasic positive airway pressure ventilation offers the advantage of significantly reduced peak inspiratory and positive end-expiratory pressures at a lower FIO2 and with at least similar oxygenation and CO2 removal as achieved by volume-controlled mechanical ventilation. Our results are in line with previous reports on nonleukopenic patients and suggest that the positive effects of pressure-limited mechanical ventilation are independent of circulating white blood cells. Further studies are mandatory to demonstrate clinical benefit in this critically ill patient population.
authors.affiliation: Department of Internal Medicine, University of Muenster, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Kiehl
authors.forename: C
authors.initials: C
authors.lastname: Schiele
authors.forename: W
authors.initials: W
authors.lastname: Stenzinger
authors.forename: J
authors.initials: J
authors.lastname: Kienast
mesh_terms: D000208:Acute Disease; D000328:Adult; D000970:Antineoplastic Agents / Q000009:adverse effects; D005260:Female; D006801:Humans; D007970:Leukopenia / Q000139:chemically induced / Q000150:complications*; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D011175:Positive-Pressure Respiration / Q000379:methods*; D011446:Prospective Studies; D012131:Respiratory Insufficiency / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D015656:Respiratory Mechanics; D012720:Severity of Illness Index; D013997:Time Factors
chemical_list: D000970:Antineoplastic Agents