Chest
Volume 102, Issue 2, August 1992, Pages 568-572
Journal home page for Chest

Clinical Investigations in Critical Care
Pulmonary Barotrauma in Mechanical Ventilation: Patterns and Risk Factors

https://doi.org/10.1378/chest.102.2.568Get rights and content

The incidence of mediastinal emphysema (ME) and pneumothorax (PTX) was analyzed to determine the roentgenographic patterns and risk factors for the development of barotrauma in a population of mechanically ventilated patients. The roentgenograms of 139 intubated patients admitted to our medical intensive care unit over a ten-month period were evaluated for the presence of ME and PTX. Barotrauma was diagnosed in 34 of these patients, and ME was the initial manifestation in 24 patients. Of these patients with initial ME, ten subsequently developed PTX, a positive predictive value of 42 percent. The adult respiratory distress syndrome (ARDS) patient population was at highest risk for barotrauma, with an intermediate risk seen in those admitted with COPD or pneumonia. Values of peak inspiratory pressure, positive end-expiratory pressure level, respiratory rate, tidal volume, and minute ventilation were significantly elevated in patients who developed barotrauma as compared with patients who did not develop barotrauma. However, these elevations in part reflect the high incidence of barotrauma in the ARDS population, a patient group in which all of the above parameters were elevated.

Section snippets

MATERIAL AND METHODS

The medical records and chest roentgenograms of all patients requiring ventilatory support in the Hohenburg Critical Care Unit at the University of Alabama at Birmingham, a general medical intensive care unit (ICU), over a ten-month period were reviewed retrospectively. Patients were excluded if barotrauma was present prior to hospital admission or if the duration of ventilatory support was less than 24 h. One hundred forty-eight patients were identified. In nine cases, roentgenograms were

Incidence and Risk Factors

Barotrauma occurred in 34 patients (24 percent): 29 patients (21 percent) developed ME, and 20 patients (14 percent) developed PTX. Both ME and PTX occurred in 15 patients. Table 1 shows a breakdown of barotrauma cases according to admitting diagnosis. The highest rate of occurrence was seen in the adult respiratory distress syndrome (ARDS) group, with an intermediate risk seen in patients with chronic obstructive pulmonary disease (COPD) and pneumonia. Together, these diseases accounted for 60

DISCUSSION

In their landmark article published in 1944, Macklin and Macklin9 used animal models to develop a mechanism for the development of extra-alveolar air, concluding that the initial site of disruption is the base of perivascular alveoli and that risk for such disruption is primarily related to the pressure gradient between the alveolus and the vascular sheath. Air in the vascular sheath, or pulmonary interstitial emphysema (PIE), should therefore develop prior to other forms of barotrauma, with

REFERENCES (20)

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

Cited by (0)

Dr. Gammon is under fellowship training support of the American College of Chest Physicians (Marion Merrell Dow Award, 1991-92).

Manuscript received September 16; revision accepted March 9.

View full text