Study objective: To measure the surface pressure on the face of a patient placed in the prone position with the most commonly used prone positioning devices, a non-face-contoured positioner (PP) and a new face-contoured device (PV).
Design: Prospective, randomized comparison.
Setting: Operating room in an American academic medical center.
Subjects: 35 randomly recruited adult volunteers.
Interventions: Surface pressure on the face was measured in awake subjects placed in the prone position, with the head and neck in the position of most comfort, using both the PP and PV devices.
Measurements: Surface pressure was obtained using an array of small transducers imbedded in a thin cushion that was interfaced between the face and positioning device. The amount of extension or flexion of the head on the neck was estimated using an angular measurement of eye-ear line and horizontal line.
Main results: The average surface pressure on the face was less with the PV than with the PP (21 +/- 3 mmHg vs. 27 +/- 5 mmHg; p < 0.0001). The number of areas where pressure exceeded 30 mmHg and 50 mmHg was lower for the PV than the PP (15 +/- 7.5 areas vs. 19 +/- 7.2 areas > 30 mmHg; p < 0.05; 5.2 +/- 3.3 areas vs. 9.0 +/- 5.0 areas > 50 mmHg; p < 0.0001). Pressure on the chin increased with extension of the head or neck (p < 0.05) with both devices.
Conclusions: Surface pressure on the face in the prone position is 29% higher with the non-face-contoured PP than with the face-contoured PV. The number of areas on the face where the surface pressure is greater than 50 mmHg is 80% higher with the PP than the PV. Small degrees of head extension increases pressure on the chin. Both devices produce areas of pressure, typically over the chin, which may be associated with local skin damage. Keeping the head and neck in a non-flexed, non-extended position may minimize pressures.