Prone Position and Mechanical Ventilation

Reviewed and revised 19 May 2014

OVERVIEW

Prone positioning can be used in mechanically ventilated patients with severe hypoxic respiratory failure to optimise oxygenation

• most studied  in patients with acute respiratory distress syndrome (ARDS) where short lived improvements in oxygenation are common (70%) and sometimes dramatic (e.g. Gattinoni et al, 2001). Some patients have no effect and others have a long lasting effect, persisting well after rolling supine again.
• the PROSEVA trial found a marked mortality benefit in patients with severe ARDS (PF ratio <150)

Refer to Prone Positioning for Hypoxic Respiratory Failure on INTENSIVE for the Alfred ICU guideline, cognitive aid, and checklist for prone ventilation.

INDICATIONS

• severe ARDS with life threatening, refractory hypoxaemia
• prone positioning may also be used for patients with posterior wounds, burns and skin flaps

CONTRAINDICATIONS

• untrained staff
• increased intracranial pressure
• increased abdominal pressure
• abdominal and chest wounds
• C-spine precautions
• extreme obesity
• haemodynamic instability

PROCEDURE

• assemble sufficient trained staff to coordinate positioning safely
• provide padding and support for potential pressure areas (face, upper chest, pelvis, knees)
• turn patient prone
• abdomen should hang between two pillows/ supports
• duration varies among protocols (e.g. 6-16 hours a day for up to 10 days)

See this video from the PROSEVA trial paper in NEJM:

PHYSIOLOGICAL EFFECTS

Supine position

• reduction in VC
• reduction FRC

Prone position

• optimisation of V/Q matching (increased blood flow to the dependent lung)
• increase in FRC
• reduced atelectasis
• facilitates secretion drainage
• less lung deformation in the prone position (increased homogeneity) -> increased ventilation
• abdomen is less likely to distend when in prone position -> increase in FRC
• heart sits against sternum (rather than left lung) -> lung is less compressed
• decreased transpleural pressure gradient between dependent and non-dependent lung in the prone position
• plateau pressure is more uniformly distributed when prone -> more uniform alveolar ventilation
• recruitment manoeuvres have been shown to be more effective in the prone position
• alterations in chest wall mechanics -> allowing lungs to inflate at lower pressures
• dorsoventral orientation of large airways

COMPLICATIONS

• decreased enteral nutrition
• ETT obstruction or dislodgement;
• chest tube and abdominal drain dislodgement
• increased intrabdominal pressure
• increased intracranial pressure
• difficulty monitoring (e.g. ECG lead placement)
• labour intensive
• difficult to perform procedures or reintubate
• may delay referral to other potentially life-saving measures such as ECMO
• facial oedema
• pressure trauma:
  • -> ocular
  • -> blindness, orbital skin necrosis
  • -> bridge of nose
  • -> mentum
  • -> humeral head
  • -> breast implants
  • -> ASIS
  • -> male genitals
  • -> knees

EVIDENCE

Summary

• there have been multiple conflicting RCTs but the weight of evidence now suggests prone ventilation is beneficial in selected severe ARDS patients
• Gattinoni et al 2001 was the original study showing improvement in oxygenation of most patients with ALI /ARDS by proning
• Recent meta-analyses suggest a mortality benefit for patients with severe ARDS (PF ratio <100), with an NNT of 11
• Subsequent to the above meta-analyses, the PROSEVA trial by Guerin et al 2013 showed a marked mortality benefit (NNT = 6) for prone ventilation in severe ARDS  (28-day mortality 16% prone versus 32.8% supine)

AN APPROACH

• Use proning for severe ARDS if refractory to other treatments, trained staff are available and ECMO is not otherwise required

References and Links

Journal articles and textbooks

• Abroug F, Ouanes-Besbes L, Dachraoui F, Ouanes I, Brochard L. An updated study-level meta-analysis of randomised controlled trials on proning in ARDS and acute lung injury. Crit Care. 2011;15(1):R6. PMC3222033.
• Fessler HE, Talmor DS. Should prone positioning be routinely used for lung protection during mechanical ventilation? Respir Care. 2010 Jan;55(1):88-99. PMID: 20040127.
• Gattinoni L, Tognoni G, Pesenti A, Taccone P, Mascheroni D, Labarta V, Malacrida R, Di Giulio P, Fumagalli R, Pelosi P, Brazzi L, Latini R; Prone-Supine Study Group. Effect of prone positioning on the survival of patients with acute respiratory failure. N Engl J Med. 2001 Aug 23;345(8):568-73. PMID: 11529210.
• Gattinoni L, Carlesso E, Taccone P, Polli F, Guérin C, Mancebo J. Prone positioning improves survival in severe ARDS: a pathophysiologic review and individual patient meta-analysis. Minerva Anestesiol. 2010 Jun;76(6):448-54. PMID: 20473258.
• Guérin C, et al; PROSEVA Study Group. Prone positioning in severe acute respiratory distress syndrome. N Engl J Med. 2013 Jun 6;368(23):2159-68. PMID: 23688302.
• Soo Hoo. In Prone Ventilation, One Good Turn Deserves Another. New Engl J Med 2013; epublished May 20th
• Messerole E, Peine P, Wittkopp S, Marini JJ, Albert RK. The pragmatics of prone positioning. Am J Respir Crit Care Med. 2002 May 15;165(10):1359-63. PMID: 12016096.
• Pelosi P, Brazzi L, Gattinoni L. Prone position in acute respiratory distress syndrome. Eur Respir J. 2002 Oct;20(4):1017-28. PMID: 12412699.
• Sud S, Friedrich JO, Taccone P, Polli F, Adhikari NK, Latini R, Pesenti A, Guérin C, Mancebo J, Curley MA, Fernandez R, Chan MC, Beuret P, Voggenreiter G, Sud M, Tognoni G, Gattinoni L. Prone ventilation reduces mortality in patients with acute respiratory failure and severe hypoxemia: systematic review and meta-analysis. Intensive Care Med. 2010 Apr;36(4):585-99. PMID: 20130832.

Social media and web resources

• EMCrit Podcast 124 – The Logistics of Proning for ARDS (2014)
• ICN — Podcast 22: Paul Goldrick on Prone Ventilation and Pulmonary Vasodilators (2012)
• Resus.ME — Prone ventilation in ARDS