Chinese Society of Critical Care Medicine-CSCCM 10th Anniversary

讲座摘要

ARDS患者PEEP的应用 PEEP in Acute Respiratory Distress Syndrome

Laurent Brochard

讲座课件

Réanimation Médicale, INSERM U 955 and Hopital Henri Mondor

Université Paris 12, Assistance Publique-Hopitaux de Paris 94000, Créteil, France

Address correspondence to

E-mail: laurent.brochard@hmn.aphp.fr

Website : www.reamondor.aphp.fr

Abstract

Mechanical ventilation (MV) is critical for survival of many patients with acute lung injury and the acute respiratory distress syndrome (ALI/ARDS). Without MV death may occur within hours to days from acute hypoxemic and hypercarbic respiratory failure.

However, MV can also cause additional lung injury (ventilator-induced lung injury, VILI), which may delay or prevent recovery from acute respiratory failure.

Positive End-Expiratory Pressure (PEEP) is a cornerstone in the ventilatory treatment of ARDS:

it is used to keep the lung open, allowing better gas exchange and also reducing the risk of repetitive opening and closing phenomena in the small airways and alveoli.

In ARDS patients, some unstable lung units open with each inspiration and close during expiration.

Mechanical forces associated with repeated opening and closing may deplete surfactant and injure small bronchioles and alveoli.

Lung injury may also result from excessive stress and strain in the parenchymal connections between aerated and non-aerated lung units.

Although ventilation without PEEP in ARDS should never happen, the individual titration of PEEP remains a matter of research.

Traditional approaches to MV in ARDS utilize PEEPs of approximately 5 to 12 cm H2O.

With these PEEP levels, acceptable arterial oxygenation can be achieved in most ARDS patients without using very high, potentially toxic concentrations of inspired oxygen.

In clinical trials of higher PEEP in ALI/ARDS, mortality was not significantly different in any of the studies^1-3.

Ventilator-free days was significantly different in the EXPRESS study³ in which higher PEEP was associated with more ventilator-free days (medians of 7 versus 3, P = 0.04) and more organ failure-free days (6 versus 2, P = 0.04).

The PEEP titration was based on maximizing recruitment while limiting plateau pressure.

In some ARDS patients, higher PEEP causes substantial recruitment of previously atelectatic or fluid-filled alveoli (PEEP-responders).

In other ARDS patients, higher PEEP causes little or no recruitment (PEEP-nonresponders).

Better differentiating recruiters and non-recruiters is a challenge for the future.

Because ALI patients without ARDS are rarely recruitable, high PEEP should probably not be used in this subgroup.

References

Brower RG, Lanken PN, MacIntyre N, Matthay MA, Morris A, Ancukiewicz M, Schoenfeld D, Thompson BT: Higher versus lower positive end-expiratory pressures in patients with the acute respiratory distress syndrome. N Engl J Med 2004; 351: 327-36

Meade MO, Cook DJ, Guyatt GH, Slutsky AS, Arabi YM, Cooper DJ, Davies AR, Hand LE, Zhou Q, Thabane L, Austin P, Lapinsky S, Baxter A, Russell J, Skrobik Y, Ronco JJ, Stewart TE: Ventilation strategy using low tidal volumes, recruitment maneuvers, and high positive end-expiratory pressure for acute lung injury and acute respiratory distress syndrome: a randomized controlled trial. JAMA 2008; 299: 637-45

Mercat A, Richard JC, Vielle B, Jaber S, Osman D, Diehl JL, Lefrant JY, Prat G, Richecoeur J, Nieszkowska A, Gervais C, Baudot J, Bouadma L, Brochard L: Positive end-expiratory pressure setting in adults with acute lung injury and acute respiratory distress syndrome: a randomized controlled trial. Jama 2008; 299: 646-55

第二届中法危重病医学研讨会暨上海重症医学论坛（2009年12月中国上海）