Chest
Volume 96, Issue 6, December 1989, Pages 1356-1359
Journal home page for Chest

Clinical Investigations in Critical Care
Cardiorespiratory Effects of Pressure Controlled Inverse Ratio Ventilation in Severe Respiratory Failure

https://doi.org/10.1378/chest.96.6.1356Get rights and content

Cardiorespiratory values were measured in nine patients with severe respiratory failure before and following initiation of pressure controlled inverse ratio ventilation (PC-IRV) at an inspiratory to expiratory ratio of 2:1. All patients showed increases in PaO2, with the mean PaO2 rising from 63±4 (mean±SEM) to 76±8 mm Hg. Peak inspiratory pressure fell from 44±4 to 39±2 cm H2O. There were no significant changes in any hemodynamic or oxygen metabolism variable associated with the institution of PC-IRV. In particular, no significant alteration in cardiac index, pulmonary artery pressures, oxygen delivery, oxygen consumption, or oxygen extraction ratio occurred with the use of PC-IRV. These results suggest that PC-IRV may be a useful ventilatory modality in the treatment of severe respiratory failure since it results in improvement in arterial oxygenation without any deterioration in hemodynamic or tissue oxygen metabolism parameters.

Section snippets

Patients

Nine patients (Table 1) with severe ARDS, as manifested by diffuse pulmonary infiltrates on chest roentgenograms, arterial hypoxemia with widened A-a gradients despite supplemental oxygen, pulmonary capillary wedge pressures (WP) less than 20 mm Hg, and decreased static and dynamic thoracic compliance were entered in the study. In each case, the patient was placed on PC-IRV at the request of the attending physician, who judged the patient to be failing conventional volume controlled ventilation

Results

Table 1 summarizes the characteristics of the patient population studied. Four men and five women were included. The average age was 46±4 years.

Arterial blood gas values, arterial oxygen saturation and peak inspiratory pressures before and after initiation of PC-IRV are presented in Table 2. All patients showed an increase in PaO2 after the institution of PC-IRV, with the range of improvement in PaO2 being 1 to 18 mm Hg. The PaCO2 decreased in seven patients and pH rose in six patients with

Discussion

In the present study, increases in PaO2 and decreases in PIP were found after the initiation of PC-IRV These results are similar to those found in previous investigations3, 4 of PC-IRV. The changes found in PaCO2 and pH were minimal and probably could have been eliminated had the end-expiratory pressure been decreased, as was made possible by the improvement in oxygenation accompanying the use of PC-IRV.

Because PC-IRV has been demonstrated to result in improved PaO2 and decreased PIP in

References (14)

There are more references available in the full text version of this article.

Cited by (103)

  • Mechanical Ventilation

    2013, Benumof and Hagberg's Airway Management
  • Mechanical Ventilation

    2012, Benumof and Hagberg's Airway Management: Third Edition
  • Respiratory Physiology and Care

    2012, Pediatric Surgery, 2-Volume Set: Expert Consult - Online and Print
  • Respiratory Physiology and Care

    2012, Pediatric Surgery
  • General Principles of Mechanical Ventilation

    2008, Critical Care Medicine: Principles of Diagnosis and Management in the Adult
View all citing articles on Scopus

Manuscript received March 31; revision accepted May 17.

View full text