03-24-2007, 09:34 AM
A 24-year-old woman presents to the ICU with acute respiratory distress syndrome (ARDS) caused by urosepsis. She is intubated, started on mechanical ventilation, sedated, and then paralyzed. The ventilator settings are: pressure control-inverse ratio ventilation (PC-IRV) mode with an inspiratory pressure of 25 cm H2O; respiratory rate (RR), 15 breaths/min; inspiratory time, 2.5 s; Fio2, 80%; and positive end-expiratory pressure (PEEP), 8 cm H2O. On these settings, her peak inspiratory pressure (PIP) and plateau pressures (Pp) are 33 cm H2O, and tidal volume (VT) is 350 mL. Sao2 is 92% on pulse oximetry. Thirty minutes later, she becomes hypotensive, desaturates, and has decreased breath sounds over the left lung. Chest radiography shows a left-sided pneumothorax. What changes in ventilator parameters do you expect to find at this time?
1. PIP, 60 cm H2O; Pp, 60 cm H2O; VT, 350 mL; RR,
15 breaths/min
2. PIP, 60 cm H2O; Pp, 60 cm H2O; VT, 200 mL; RR,
15 breaths/min
3. PIP, 33 cm H2O; Pp, 33 cm H2O; VT, 200 mL; RR,
15 breaths/min
4. PIP, 33 cm H2O; Pp, 33 cm H2O; VT, 350 mL; RR,
40 breaths/min
1. PIP, 60 cm H2O; Pp, 60 cm H2O; VT, 350 mL; RR,
15 breaths/min
2. PIP, 60 cm H2O; Pp, 60 cm H2O; VT, 200 mL; RR,
15 breaths/min
3. PIP, 33 cm H2O; Pp, 33 cm H2O; VT, 200 mL; RR,
15 breaths/min
4. PIP, 33 cm H2O; Pp, 33 cm H2O; VT, 350 mL; RR,
40 breaths/min