In recumbent healthy individuals, the majority of time is spent in the lateral or prone position with a change in body position on average every 11.6 minutes. The physiology driving this include improved V/Q match, more negative and even distributions of pleural pressures and unweighting of soft tissues in the prone position. For proning to be effective in the treatment of acute respiratory distress syndrome (ARDS), sufficient time must be spent in the prone position with frequent turning to decrease facial edema. Manual proning is difficult and labor intensive and therefore has been used mainly as a rescue intervention. New technology addresses these issues. We studied an automated bed for proning with kinetic therapy in the treatment of ALI /ARDS regarding safety, efficiency and whether increased duration of proning will lead to better outcomes and heterogeneous distribution of ARDS by CT will predict better response to proning.
Nineteen patients with ALI/ARDS were randomized on an alternating basis to 12 hours vs. 20 hours of proning on the RotoProne® Bed (KCI, San Antonio, TX). Criteria for inclusion was by ARDSnet and exclusion by Table 1.
Exclusion CriteriaIntracranial hypertensionOpen abdomen or recent median sternotomyWeight < 100 lbs or > 400 lbs.Height < 4’ 6“ or > 6’ 6”.Unstable fracturePregnancyNasal tracheal intubationGroup One received 12 hr proning /24 hr, with supine and prone intervals at 2 hr each. Group Two received 19 hr 30 min proning /24 hr, with supine intervals of 45 min and prone intervals of 3 hr 15min. Both received 62° kinetic therapy.
Table 2Table 2
ResultsGroup 1 12 hours of proningGroup 2 19.5 hours of proningp valuePatients109APS-Day 159.954.3APACHE III-Day172.764.7ALI-bed Day 13.23.1P/F Ratio Initial125.5127.1Vent Days18.104.22.168Actual ICU LOS23.118.9Actual Hospital LOS35.831.7Actual Mortality (n)42Actual Mortality (%)40.022.20.47Predicted Mortality (%)36.030.0Homogenous1Heterogenous2p valuePatients CT Scans at Enrollment514APS-Day 143.862.8APACHE III-Day153.874.30.11Repeat CT Findings-Improved3 of 39 of 9Vent Days12.415.3Actual ICU LOS18.622.0Actual Hospital LOS24.337.1Actual Mortality (n)33Actual Mortality (%)60.021.00.0531
Heterogeneous i.e., dorsal consolidation generally with ventral sparing2
Homogenous i.e., diffused pan-lung infiltrates3
After accounting for difference in severity of illness.
This pilot study demonstrates that using an automated proning device is associated with recruitment of dorsal consolidated lung, decreased pleural effusions, rapid mobilization of secretions and improved oxygenation. Homogenous CT appearance was associated with a higher mortality. Use of automated proning and kinetic therapy with long cumulative proning times is safe, can be accomplished with one nurse and was associated with a trend in decreased ventilator days and mortality.
Automation of proning may broaden the application of this therapy in ALI/ARDS. Future studies of proning in ALI/ARDS should incorporate this technology.
F. Sebat, Funding provided by KCI. Authors have no financial