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Diaphragm ultrasound as indicator of respiratory effort in critically ill patients undergoing assisted mechanical ventilation: a pilot clinical study.

Umbrello M, Formenti P, Longhi D, Galimberti A, Piva I, Pezzi A, Mistraletti G, Marini JJ, Iapichino G - Crit Care (2015)

Bottom Line: With increasing levels of pressure support, parallel reductions were found between diaphragm thickening and both diaphragm and esophageal pressure-time product (respectively, R = 0.701, p < 0.001 and R = 0.801, p < 0.001) during tidal breathing.No correlation was found between either diaphragm or esophageal pressure-time product and diaphragm excursion (respectively, R = -0.081, p = 0.506 and R = 0.003, p = 0.981), nor was diaphragm excursion correlated to diaphragm thickening (R = 0.093, p = 0.450) during tidal breathing.In patients undergoing in assisted mechanical ventilation, diaphragm thickening is a reliable indicator of respiratory effort, whereas diaphragm excursion should not be used to quantitatively assess diaphragm contractile activity.

View Article: PubMed Central - PubMed

Affiliation: Unità Operativa di Anestesia e Rianimazione, Azienda Ospedaliera San Paolo - Polo Universitario, Via A. Di Rudinì, 8-20142, Milano, Italy. michele.umbrello@fastwebnet.it.

ABSTRACT

Introduction: Pressure-support ventilation, is widely used in critically ill patients; however, the relative contribution of patient's effort during assisted breathing is difficult to measure in clinical conditions. Aim of the present study was to evaluate the performance of ultrasonographic indices of diaphragm contractile activity (respiratory excursion and thickening) in comparison to traditional indices of inspiratory muscle effort during assisted mechanical ventilation.

Method: Consecutive patients admitted to the ICU after major elective surgery who met criteria for a spontaneous breathing trial with pressure support ventilation were enrolled. Patients with airflow obstruction or after thoracic/gastric/esophageal surgery were excluded. Variable levels of inspiratory muscle effort were achieved by delivery of different levels of ventilatory assistance by random application of pressure support (0, 5 and 15 cmH2O). The right hemidiaphragm was evaluated by B- and M-mode ultrasonography to record respiratory excursion and thickening. Airway, gastric and oesophageal pressures, and airflow were recorded to calculate indices of respiratory effort (diaphragm and esophageal pressure-time product).

Results: 25 patients were enrolled. With increasing levels of pressure support, parallel reductions were found between diaphragm thickening and both diaphragm and esophageal pressure-time product (respectively, R = 0.701, p < 0.001 and R = 0.801, p < 0.001) during tidal breathing. No correlation was found between either diaphragm or esophageal pressure-time product and diaphragm excursion (respectively, R = -0.081, p = 0.506 and R = 0.003, p = 0.981), nor was diaphragm excursion correlated to diaphragm thickening (R = 0.093, p = 0.450) during tidal breathing.

Conclusions: In patients undergoing in assisted mechanical ventilation, diaphragm thickening is a reliable indicator of respiratory effort, whereas diaphragm excursion should not be used to quantitatively assess diaphragm contractile activity.

No MeSH data available.


Related in: MedlinePlus

Correlation between thickening fraction and esophageal and diaphragmatic pressure-time product. PTPes, esophageal pressure-time product per breath; PTPdi, diaphragmatic pressure-time product per breath; TF, thickening fraction; PSV, pressure support ventilation.
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Fig4: Correlation between thickening fraction and esophageal and diaphragmatic pressure-time product. PTPes, esophageal pressure-time product per breath; PTPdi, diaphragmatic pressure-time product per breath; TF, thickening fraction; PSV, pressure support ventilation.

Mentions: Diaphragm TF significantly correlated with PTPes and PTPdi (b coefficient = 4.459, P <0.001 and 2.322, P <0.001, respectively) (Figure 4), as well as with PMI (b = 1.140, P = 0.001) and P0.1 (b = 5.522, P <0.001). Negative correlation was found between TF and Vt (b = −0.030, P <0.001). No correlation was found between diaphragm TF and excursion (b = 0.002, P = 0.488).Figure 4


Diaphragm ultrasound as indicator of respiratory effort in critically ill patients undergoing assisted mechanical ventilation: a pilot clinical study.

Umbrello M, Formenti P, Longhi D, Galimberti A, Piva I, Pezzi A, Mistraletti G, Marini JJ, Iapichino G - Crit Care (2015)

Correlation between thickening fraction and esophageal and diaphragmatic pressure-time product. PTPes, esophageal pressure-time product per breath; PTPdi, diaphragmatic pressure-time product per breath; TF, thickening fraction; PSV, pressure support ventilation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4403842&req=5

Fig4: Correlation between thickening fraction and esophageal and diaphragmatic pressure-time product. PTPes, esophageal pressure-time product per breath; PTPdi, diaphragmatic pressure-time product per breath; TF, thickening fraction; PSV, pressure support ventilation.
Mentions: Diaphragm TF significantly correlated with PTPes and PTPdi (b coefficient = 4.459, P <0.001 and 2.322, P <0.001, respectively) (Figure 4), as well as with PMI (b = 1.140, P = 0.001) and P0.1 (b = 5.522, P <0.001). Negative correlation was found between TF and Vt (b = −0.030, P <0.001). No correlation was found between diaphragm TF and excursion (b = 0.002, P = 0.488).Figure 4

Bottom Line: With increasing levels of pressure support, parallel reductions were found between diaphragm thickening and both diaphragm and esophageal pressure-time product (respectively, R = 0.701, p < 0.001 and R = 0.801, p < 0.001) during tidal breathing.No correlation was found between either diaphragm or esophageal pressure-time product and diaphragm excursion (respectively, R = -0.081, p = 0.506 and R = 0.003, p = 0.981), nor was diaphragm excursion correlated to diaphragm thickening (R = 0.093, p = 0.450) during tidal breathing.In patients undergoing in assisted mechanical ventilation, diaphragm thickening is a reliable indicator of respiratory effort, whereas diaphragm excursion should not be used to quantitatively assess diaphragm contractile activity.

View Article: PubMed Central - PubMed

Affiliation: Unità Operativa di Anestesia e Rianimazione, Azienda Ospedaliera San Paolo - Polo Universitario, Via A. Di Rudinì, 8-20142, Milano, Italy. michele.umbrello@fastwebnet.it.

ABSTRACT

Introduction: Pressure-support ventilation, is widely used in critically ill patients; however, the relative contribution of patient's effort during assisted breathing is difficult to measure in clinical conditions. Aim of the present study was to evaluate the performance of ultrasonographic indices of diaphragm contractile activity (respiratory excursion and thickening) in comparison to traditional indices of inspiratory muscle effort during assisted mechanical ventilation.

Method: Consecutive patients admitted to the ICU after major elective surgery who met criteria for a spontaneous breathing trial with pressure support ventilation were enrolled. Patients with airflow obstruction or after thoracic/gastric/esophageal surgery were excluded. Variable levels of inspiratory muscle effort were achieved by delivery of different levels of ventilatory assistance by random application of pressure support (0, 5 and 15 cmH2O). The right hemidiaphragm was evaluated by B- and M-mode ultrasonography to record respiratory excursion and thickening. Airway, gastric and oesophageal pressures, and airflow were recorded to calculate indices of respiratory effort (diaphragm and esophageal pressure-time product).

Results: 25 patients were enrolled. With increasing levels of pressure support, parallel reductions were found between diaphragm thickening and both diaphragm and esophageal pressure-time product (respectively, R = 0.701, p < 0.001 and R = 0.801, p < 0.001) during tidal breathing. No correlation was found between either diaphragm or esophageal pressure-time product and diaphragm excursion (respectively, R = -0.081, p = 0.506 and R = 0.003, p = 0.981), nor was diaphragm excursion correlated to diaphragm thickening (R = 0.093, p = 0.450) during tidal breathing.

Conclusions: In patients undergoing in assisted mechanical ventilation, diaphragm thickening is a reliable indicator of respiratory effort, whereas diaphragm excursion should not be used to quantitatively assess diaphragm contractile activity.

No MeSH data available.


Related in: MedlinePlus