Ventilator-associated pneumonia: the role of ventilator management strategies

Ventilator management strategies can affect the risk for ventilator-associated pneumonia in 3 ways: the development of ventilator-induced lung injury; the need for potentially harmful tradeoffs in providing lung-protective ventilatory strategies; and the prolongation of the duration of mechanical ventilation from iatrogenic factors. Strategies to reduce ventilator-induced lung injury include a smaller tidal volume and careful attention to reducing the maximum pressures in the lung. These lung-protective strategies, however, may require tradeoffs with factors that may in themselves produce risks for ventilator-associated pneumonia. Specifically, hypercapnia, discomfort requiring sedation, and atelectasis may all be potential problems with a lung-protective strategy. However, the weight of evidence suggests that beneficial outcomes from lung-protective strategies outweigh any potential harm from these tradeoffs. Finally, properly performed weaning protocols based on clinical evidence should reduce any iatrogenic delays in ventilator weaning and thereby minimize prolongation of unneeded mechanical ventilatory support.