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  • Meeting abstract
  • Open Access

Ventilator beyond ventilation: impact of positive end expiratory pressure on peak expiratory flow in mechanically ventilated patients under three modalities of manually assisted coughing

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Critical Care20037 (Suppl 3) :P50

  • Published:


  • Pneumothorax
  • Statistical Significant Difference
  • Peak Expiratory Flow
  • Small Airway
  • Functional Residual Capacity


Bronchopulmonary hygiene physical therapy refers to techniques that promote clearance of airway secretion. One of these techniques is manually assisted coughing (MAC), which could have early smaller airways narrowing or collapsing as an undesirable effect. Positive end expiratory pressure (PEEP) promotes small airway stability, and increases functional residual capacity and pulmonary volume at the end of expiration. The purpose of this study was to analyze whether the PEEP effects described are able to optimize peak expiratory flow (PEF) during MAC.


A prospective, experimental and blinded study.


Twenty-six patients (mean age 60 ± 13.5 years) admitted to the Hospital Português Clinical–Surgery Intensive Care Unit and requiring controlled mechanical ventilation were assessed. Patients with previous pulmonary disease, hemodynamic instability, rib cage and/or abdominal abnormalities, scoliosis, pregnancy, obesity, a cardiac pacemaker, pneumothorax and unstable thorax were excluded. The PEF variation during MAC with a baseline PEEP (mean 5.5 ± 1.44 cmH2O; n = 26) was compared with the same modality with a PEEP of 12 cmH2O (n = 16). PEF was measured by the Navigator Graphics Monitor (Newport Medical Instruments Inc., Newport Beach, CA, USA). MAC was performed five times in each hand position (unilateral, bilateral and thoracic–abdominal) in an alleatory way. The Mann–Whitney rank-sum test was used to assess differences between the groups. Differences with P < 0.05 were considered significant.


Means of PEF variations are presented in Table 1. When all variations of PEF in each modality of MAC were compared with the variations after addition of PEEP, statistical significant differences were noted. When comparing the different modalities of MAC with adding PEEP, no statistical significant differences were noted.

Baseline PEEP

PEEP 12 cmH2O

Unilateral MAC

0.711 ± 0.29*

0.963 ± 0.267*

Bilateral MAC

0.773 ± 0.30*

1.035 ± 0.274*

Thoracic–abdominal MAC

0.756 ± 0.26*

1.073 ± 0.288*

PEEP, positive end expiratory pressure; MAC, manually assisted coughing. *P < 0.0001.


PEEP was efficient in MAC optimization and in increasing the PEF. The association of PEEP during MAC in mechanically ventilated patients is recommended.

Authors’ Affiliations

Intensive Care Unit, Hospital Português, Av Princesa Isabel 02, Salvador, Bahia, Brazil
Intensive Care Unit, Hospital Português, Av Princesa Isabel 02, Salvador, Bahia, Brazil


© BioMed Central Ltd 2003