Ramped Position Improves Oxygenation During Mechanical Ventilation for Patients With Severe Obesity
Appropriate body positioning is crucial for maximizing the effectiveness of mechanical ventilation in patients with obesity. The ramped position is generally used for patients who are difficult to intubate, especially patients with severe obesity. We hypothesized that the ramped position would also improve ventilation and oxygenation in patients with obesity vs the semi-Fowler position. This retrospective study compared data from 17 total patients with obesity (body mass index ≥35 kg/m2) who underwent intubated general anesthesia in the ramped position vs the semi-Fowler position. Differences in 2 indices of respiratory function, alveolar‐arterial oxygen gradient (P(A-a)DO2; ventilation) and arterial partial pressure of oxygen/fraction of inspired oxygen (P/F ratio; oxygenation), were measured during the maintenance of general anesthesia between the 2 groups. The mean (SD) P(A-a)DO2 was significantly lower in the ramped group (168.83 [54.18] mm Hg) than in the semi-Fowler group (273.33 [39.72] mm Hg; P = .012), and the mean (SD) P/F ratio was significantly higher in the ramped group (354.44 [88.88]) than in the semi-Fowler group (225.40 [67.49]; P = .002). The ramped position was associated with improved ventilation and pulmonary oxygenation vs the semi-Fowler position during mechanical ventilation in patients with obesity.Objective
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Illustrations of the Horizontal Supine Position and 3 Raised Upper Body Positions
(A) The horizontal supine position. (B) The reverse Trendelenburg position, in which the patient lies supine on a flat surface with the head higher than the feet and inclined at 25° to 30°. (C) The beach chair position, comprising the reverse Trendelenburg position with the legs lifted to the abdomen. (D) The semirecumbent position, in which the patient lies supine with the lower limbs horizontal and the upper body elevated at 45° to 60°.
Photographs of Patients in the Ramped and Semi-Fowler Positions
(A) In the ramped position, the patient’s shoulders and neck are lifted in addition to the upper body, and the sternal notch and external auditory meatus are horizontally aligned. (B) In the semi-Fowler position, the patient lies on their back with the head and torso raised at an angle of approximately 30° and the legs laid out straight on the bed.
Diagrams Showing the Differences Between the Horizontal, Ramped, and Semi-Fowler Positions
Locations of the external auditory meatus (EM) and the sternal notch (SN) as well as the shoulder-to-neck angles (θ) in (A) the horizontal supine position, (B) the ramped position, and (C) the semi-Fowler position. (A) The SN is positioned above the EM in the horizontal supine position because of the large anteroposterior diameter of the chest in patients with obesity. (B) The ramped position, in which the patient’s neck and shoulders are elevated to achieve horizontal alignment of the EM and the SN. The region from the shoulders to the neck is increased at an angle of θ. (C) The semi-Fowler position, with a smaller θ than in the ramped position because the SN is above the EM. Abbreviations: EM, external auditory meatus; SN, sternal notch; θ, shoulder-to-neck angle.
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