Korean J Crit Care Med.  2006 Dec;21(2):89-94.

Effects of Ventilation Modes and Levels of PEEP on Respiratory Mechanics during Controlled Ventilation under General Anesthesia

• Park JC
• Park SH
• Kwag HJ
• Park SY

Abstract

BACKGROUND
Application of PEEP increases lung volume and improves oxygenation. High PEEP levels may cause alveolar overdistension or barotrauma. It was hypothesized that there will be an effect of level of PEEP on respiratory resistance and an effect of ventilatory mode on respiratory compliance. This study aimed to investigate the effects of ventilation modes and levels of PEEP on respiratory mechanics during controlled ventilation under general anesthesia.
METHODS
In 14 mechanically ventilated patients without cardiopulmonary symptoms and signs, we measured the respiratory mechanics using the inspiration interrupter technique during a constant flow. Dynamic and static compliance, airway resistance, visco-elastic tissue and total respiratory system resistance were calculated at 0, 5, 10, 15, and 20 cmH2O of positive end-expiratory pressure (PEEP) in VCV mode, VCV with inspiratory pause mode, and PCV mode, respectively.
RESULTS
The dynamic compliance of the PCV mode was higher than that of the VCV mode. The highest static compliance was at 10 cmH2O PEEP. At 20 cmH2O PEEP, pulmonary compliance was decreased and the tissue resistance was increased.
CONCLUSIONS
These results suggest that the respiratory mechanics including respiratory resistance should be monitored for applying PEEP. Further studies on clinical condition such as acute lung injury and ARDS were needed.

Keyword

Compliance; Mechanical ventilation; Positive end-expiratory pressure; Resistance; Respiratory mechanics

MeSH Terms

Acute Lung Injury
Airway Resistance
Anesthesia, General*
Barotrauma
Compliance
Humans
Lung
Oxygen
Positive-Pressure Respiration
Respiration, Artificial
Respiratory Mechanics*
Respiratory System
Ventilation*
Oxygen