What is normal intra-abdominal pressure and how is it affected by positioning, body mass and positive end-expiratory pressure?

Background Morbidly obese patients, during anesthesia and paralysis, experience more severe impairment of respiratory mechanics and gas exchange than normal subjects. The authors hypothesized that positive end-expiratory pressure (PEEP) induces different responses in normal subjects (n = 9; body mass index < 25 kg/m2) versus obese patients (n = 9; body mass index > 40 kg/m2). Methods The authors measured lung volumes (helium technique), the elastances of the respiratory system, lung, and chest wall, the pressure-volume curves (occlusion technique and esophageal balloon), and the intraabdominal pressure (intrabladder catheter) at PEEP 0 and 10 cm H2O in paralyzed, anesthetized postoperative patients in the intensive care unit or operating room after abdominal surgery. Results At PEEP 0 cm H2O, obese patients had lower lung volume (0.59 +/- 0.17 vs. 2.15 +/- 0.58 l [mean +/- SD], P < 0.01); higher elastances of the respiratory system (26.8 +/- 4.2 vs. 16.4 +/- 3.6 cm H2O/l, P < 0.01), lung (17.4 +/- 4.5 vs. 10.3 +/- 3.2 cm H2O/l, P < 0.01), and chest wall (9.4 +/- 3.0 vs. 6.1 +/- 1.4 cm H2O/l, P < 0.01); and higher intraabdominal pressure (18.8 +/-7.8 vs. 9.0 +/- 2.4 cm H2O, P < 0.01) than normal subjects. The arterial oxygen tension was significantly lower (110 +/- 30 vs. 218 +/- 47 mmHg, P < 0.01; inspired oxygen fraction = 50%), and the arterial carbon dioxide tension significantly higher (37.8 +/- 6.8 vs. 28.4 +/- 3.1, P < 0.01) in obese patients compared with normal subjects. Increasing PEEP to 10 cm H2O significantly reduced elastances of the respiratory system, lung, and chest wall in obese patients but not in normal subjects. The pressure-volume curves were shifted upward and to the left in obese patients but were unchanged in normal subjects. The oxygenation increased with PEEP in obese patients (from 110 +/-30 to 130 +/- 28 mmHg, P < 0.01) but was unchanged in normal subjects. The oxygenation changes were significantly correlated with alveolar recruitment (r = 0.81, P < 0.01). Conclusions During anesthesia and paralysis, PEEP improves respiratory function in morbidly obese patients but not in normal subjects.

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The relationship of body mass index to intra-abdominal pressure as measured by multichannel cystometry

International Urogynecology Journal ◽

10.1007/bf02765589 ◽

1997 ◽

Vol 8 (6) ◽

pp. 323-326 ◽

Cited By ~ 162

Author(s):

K. L. Noblett ◽

J. K. Jensen ◽

D. R. Ostergard

Keyword(s):

Body Mass Index ◽

Body Mass ◽

Abdominal Pressure ◽

Relationship Of ◽

The Relationship

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Effect of Positive End-Expiratory Pressure on Intra-abdominal Pressure

Southern Medical Journal ◽

10.1097/00007611-199106000-00006 ◽

1991 ◽

Vol 84 (6) ◽

pp. 697-700 ◽

Cited By ~ 34

Author(s):

ANTHONY M. SUSSMAN ◽

CARL R. BOYD ◽

JAMES S. WILLIAMS ◽

ROBERT J. DrBENEDETTO

Keyword(s):

Abdominal Pressure ◽

Positive End Expiratory Pressure

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Body Habitus and Dynamic Surgical Conditions Independently Impair Pulmonary Mechanics during Robotic-assisted Laparoscopic Surgery

Anesthesiology ◽

10.1097/aln.0000000000003442 ◽

2020 ◽

Vol 133 (4) ◽

pp. 750-763 ◽

Cited By ~ 2

Author(s):

William G. Tharp ◽

Serena Murphy ◽

Max W. Breidenstein ◽

Collin Love ◽

Alisha Booms ◽

...

Keyword(s):

Body Mass Index ◽

Laparoscopic Surgery ◽

Body Mass ◽

Mechanical Strain ◽

Lung Mechanics ◽

Pulmonary Mechanics ◽

Positive End Expiratory Pressure ◽

Body Habitus ◽

Wide Range ◽

Surgical Conditions

Background Body habitus, pneumoperitoneum, and Trendelenburg positioning may each independently impair lung mechanics during robotic laparoscopic surgery. This study hypothesized that increasing body mass index is associated with more mechanical strain and alveolar collapse, and these impairments are exacerbated by pneumoperitoneum and Trendelenburg positioning. Methods This cross-sectional study measured respiratory flow, airway pressures, and esophageal pressures in 91 subjects with body mass index ranging from 18.3 to 60.6 kg/m2. Pulmonary mechanics were quantified at four stages: (1) supine and level after intubation, (2) with pneumoperitoneum, (3) in Trendelenburg docked with the surgical robot, and (4) level without pneumoperitoneum. Subjects were stratified into five body mass index categories (less than 25, 25 to 29.9, 30 to 34.9, 35 to 39.9, and 40 or higher), and respiratory mechanics were compared over surgical stages using generalized estimating equations. The optimal positive end-expiratory pressure settings needed to achieve positive end-expiratory transpulmonary pressures were calculated. Results At baseline, transpulmonary driving pressures increased in each body mass index category (1.9 ± 0.5 cm H2O; mean difference ± SD; P < 0.006), and subjects with a body mass index of 40 or higher had decreased mean end-expiratory transpulmonary pressures compared with those with body mass index of less than 25 (–7.5 ± 6.3 vs. –1.3 ± 3.4 cm H2O; P < 0.001). Pneumoperitoneum and Trendelenburg each further elevated transpulmonary driving pressures (2.8 ± 0.7 and 4.7 ± 1.0 cm H2O, respectively; P < 0.001) and depressed end-expiratory transpulmonary pressures (–3.4 ± 1.3 and –4.5 ± 1.5 cm H2O, respectively; P < 0.001) compared with baseline. Optimal positive end-expiratory pressure was greater than set positive end-expiratory pressure in 79% of subjects at baseline, 88% with pneumoperitoneum, 95% in Trendelenburg, and ranged from 0 to 36.6 cm H2O depending on body mass index and surgical stage. Conclusions Increasing body mass index induces significant alterations in lung mechanics during robotic laparoscopic surgery, but there is a wide range in the degree of impairment. Positive end-expiratory pressure settings may need individualization based on body mass index and surgical conditions. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

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