Combined Pressure Control/High Frequency Ventilation in Adult Respiratory Distress Syndrome and Sickle Cell Anemia: Case Report
He developed worsening respiratory distress and was intubated (Fig 1) and given conventional positive pressure ventilation in the pressure control mode (Siemens-Elema Servov-entilator 900C, Sweden). Peak inspiratory pressure (PIP) was 36 cm H2O, PEEP was 5 cm H2O, the fractional inspired concentration of oxygen (FI02) was 0.6, and mean airway pressure (MAP) was 14 cm H2O. Continuous infusions of dobutamine and furo-semide (Lasix) were used so.
Full volume exchange transfusion with normal packed red blood cells was performed. Despite efforts to limit peak pressures by using small tidal volumes and permissive hypercapnia, the PIP 24 h after intubation had to be increased to 41 cm H2O to achieve tidal volumes of 6 to 7 ml/kg. Frequent airway suctioning was required to remove mucous plugs. On the third day after intubation, the patient developed crepitus over the thorax and abdominal wall, and radiographs revealed extrapul-monary collections of air in the mediastinum (Fig 2) and peritoneal cavity. On the following day, the PIP needed to maintain a tidal volume of 6 to 7 ml/kg was 44 cm H2O, and IRV was used (inspiratory to expiratory ratio, or I:E, of 1.2:1).
The patient was changed to the PVDV on the following day as air leaks worsened. Initial settings included a background respiratory rate of 30 per minute (I:E of 1:1), a high frequency rate of 580/min, an FI02 of 0.5, and a PIP of 35 cm H2O. The peak airway pressure of the conventional background rate needed to maintain adequate ventilation was reduced rapidly during the first 24 h. The background respiratory rate was gradually reduced as well (to 21/min after 24 h) in response to improved ventilation (blood gas results in Table 1).
Figure 1. Chest radiograph shortly after intubation, notable for bilateral consolidation of lung fields.
Figure 2. Chest radiograph 1 day prior to initiation of PVDV, with pneumomediastinum and patchy infiltrates.
Table 1—Representative Blood Gas Results
|Arterial (A) orVenous (V) Sample||Blood Gas Result|
Category: Respiratory Symptoms
Tags: barotrauma, high frequency ventilation, sickle cell anemia