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Pulmonary Barotrauma in Mechanical Ventilation

1993; Elsevier BV; Volume: 104; Issue: 3 Linguagem: Inglês

10.1378/chest.104.3.987a

1931-3543

Thomas M. Fuhrman,

Trauma Management and Diagnosis

Tb the Editor:Pulmonary barotrauma, while not truly iatrogenic, is a consequence of our therapy for patients requiring mechanical ventilation. Anyone involved in the care of ICU patients would like to reduce its incidence. Therefore, it was with great interest that I read the report by Gammon et al,1Gammon RB Shin MS Buchalter SE Pulmonary barotrauma in mechanical ventilation: patterns and risk factors.Chest. 1992; 102: 568-572Abstract Full Text Full Text PDF PubMed Scopus (184) Google Scholar which appeared in the August 1992 issue of Chest. Their ICU had an incidence of barotrauma of 24.5 percent (34/139) in patients requiring mechanical ventilation for over 24 h. All except 11 patients were ventilated in the assist-control mode. This makes their results very similar to those of Mathru et al,2Mathru M Rao TLK Venus B Ventilator-induced barotrauma in controlled mechanical ventilation versus intermittent mandatory ventilation.Crit Care Med. 1983; 11: 359-361Crossref PubMed Scopus (35) Google Scholar who reported a 22 percent incidence of barotrauma in patients ventilated in the control mode, while only 7 percent of the patients ventilated with intermittent mandatory ventilation (IMV) suffered barotrauma. The patients in the control-mode group were ventilated at significantly lower peak inspiratory pressure (PIP) and positive end-expiratory pressure (PEEP) levels, yet still had three times the incidence of barotrauma. The data of Mathru et al suffer because they are 16 years old and because the patients on which they were based were both medical and surgical; therefore, a direct comparison cannot be made. However, the issue of whether it is the PIP itself or a high PIP combined with the rate at which that PIP is attained still needs to be addressed. Gammon et al did not separate out the patients on IMV. It is doubtful that the data on the small number of patients ventilated with IMV would lead to meaningful statistics, but it would be interesting to know the incidence of barotrauma in that subgroup.Another point not addressed by either Gammon et al or Mathru et al is the timing of the barotrauma. Anecdotally, the occurrence of barotrauma increases as the patient's lungs seem to be improving. A theory to explain this phenomenon involves nonhomogeneous healing of the lung and overinflation of the healthier, more compliant lung areas by the PIP and PEEP, which leads to the barotrauma. Perhaps Gammon and his coauthors could comment on this issue.Many theories and myths regarding barotrauma will exist until further reports like that of Gammon et al help to prove or dispel them. Tb the Editor: Pulmonary barotrauma, while not truly iatrogenic, is a consequence of our therapy for patients requiring mechanical ventilation. Anyone involved in the care of ICU patients would like to reduce its incidence. Therefore, it was with great interest that I read the report by Gammon et al,1Gammon RB Shin MS Buchalter SE Pulmonary barotrauma in mechanical ventilation: patterns and risk factors.Chest. 1992; 102: 568-572Abstract Full Text Full Text PDF PubMed Scopus (184) Google Scholar which appeared in the August 1992 issue of Chest. Their ICU had an incidence of barotrauma of 24.5 percent (34/139) in patients requiring mechanical ventilation for over 24 h. All except 11 patients were ventilated in the assist-control mode. This makes their results very similar to those of Mathru et al,2Mathru M Rao TLK Venus B Ventilator-induced barotrauma in controlled mechanical ventilation versus intermittent mandatory ventilation.Crit Care Med. 1983; 11: 359-361Crossref PubMed Scopus (35) Google Scholar who reported a 22 percent incidence of barotrauma in patients ventilated in the control mode, while only 7 percent of the patients ventilated with intermittent mandatory ventilation (IMV) suffered barotrauma. The patients in the control-mode group were ventilated at significantly lower peak inspiratory pressure (PIP) and positive end-expiratory pressure (PEEP) levels, yet still had three times the incidence of barotrauma. The data of Mathru et al suffer because they are 16 years old and because the patients on which they were based were both medical and surgical; therefore, a direct comparison cannot be made. However, the issue of whether it is the PIP itself or a high PIP combined with the rate at which that PIP is attained still needs to be addressed. Gammon et al did not separate out the patients on IMV. It is doubtful that the data on the small number of patients ventilated with IMV would lead to meaningful statistics, but it would be interesting to know the incidence of barotrauma in that subgroup. Another point not addressed by either Gammon et al or Mathru et al is the timing of the barotrauma. Anecdotally, the occurrence of barotrauma increases as the patient's lungs seem to be improving. A theory to explain this phenomenon involves nonhomogeneous healing of the lung and overinflation of the healthier, more compliant lung areas by the PIP and PEEP, which leads to the barotrauma. Perhaps Gammon and his coauthors could comment on this issue. Many theories and myths regarding barotrauma will exist until further reports like that of Gammon et al help to prove or dispel them. Pulmonary Barotrauma in Mechanical VentilationCHESTVol. 104Issue 3PreviewTo the Editor: Full-Text PDF