Refractory hypoxemic respiratory failure guidelines and prone positioning standard operating procedure

Publication: 26/04/2018  
Next review: 03/11/2025  
Standard Operating Procedure
ID: 5510 
Approved By: Trust Clinical Guidelines Group 
Copyright© Leeds Teaching Hospitals NHS Trust 2021  


This Standard Operating Procedure is intended for use by healthcare professionals within Leeds unless otherwise stated.
For healthcare professionals in other trusts, please ensure that you consult relevant local and national guidance.

Refractory hypoxemic respiratory failure guidelines and prone positioning standard operating procedure


To provide practical and safe guidance on the indications for and the process of turning a ventilated adult patient in the critical care unit into the prone position.

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Acute Respiratory Distress Syndrome (ARDS) is characterised by hypoxemia, pulmonary congestion and a significant decrease in lung compliance.
It is associated with substantial morbidity ranging from 27% in mild ARDS to
45% for severe ARDS.

Prone positioning is a practical intervention which can be employed in conjunction with lung protective ventilation strategy to optimise gas exchange and limit barotrauma in patients with moderate to severe hypoxemic respiratory failure associated with ARDS (Gattinoni et al 2010).

The current evidence supports a sustained improvement in oxygenation in approximately 70% of ARDS patients in whom prone positioning is utilised (Henderson et al, 2014 & Kallet 2015), whilst a recent large, multicentre RCT demonstrated a highly significant reduction in mortality at 28 and 90 days, with ventilation-free days at these intervals also being significantly greater in the prone group (Guerin et al 2013).

The PROSEVA trial identified that early implementation of prone positioning confers the greatest benefits, as attenuation of the inflammatory process in the acute phase can curtail disease progression, whilst those patients exhibiting severe ARDS (PaO2/FiO2 <100mmHg, PEEP >5cmH2O) were most responsive to prone positioning.  Furthermore, the degree of benefit is directly correlated with the amount of time spent in prone, with >12 hour sessions being recommended (Guerin et al, 2013).

In addition to this the early use of neuromuscular block has suggested a possible mortality benefit, more ventilator free days together with a lower incidence of pneumothoraces and ventilator associated lung injury (Papazian et al 2010).

Lying a patient in the prone position has many physiological effects including:

  • Increase functional residual capacity (FRC)
  • Facilitating secretion drainage
  • More evenly distributed plateau pressure - more uniform alveolar ventilation
  • Reduced atelectasis
  • Optimising the V/Q mismatch through increased blood flow to the dependent lung
  • Less abdominal distension - increased FRC
  • Increased homogeneity - increased ventilation
  • Heart sits against the sternum resulting in less compression of the left lower lung

Complications of prone positioning include:

  • Increased abdominal pressure
  • Increased intracranial pressure
  • Labour intensive
  • ETT obstruction or displacement
  • Decreased enteral nutrition
  • May delay a referral to other life saving measures such as extra corporeal membrane oxygenation (ECMO)
  • Facial oedema
  • Pressure damage to vulnerable areas of the skin

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Treatment / Management

Moderate to severe ARDS – see below (ARDS definition task force 2012)

Evidence of basal collapse/consolidation on CT scan which is refractory to physiotherapy, positioning and bronchoscopy where oxygen requirements are escalating.

Acute Respiratory Distress Syndrome

Berlin definition


Within one week of a known clinical insult or new and worsening respiratory symptoms

Chest imaging

Bilateral opacities - not fully explained by effusions, lobar/lung collapse or nodules (a)

Origin of oedema

Respiratory failure not fully explained by cardiac failure or fluid overload.

Objective assessment required (echocardiography) to exclude hydrostatic pulmonary oedema if no risk factor present

Oxygenation (b)



26.7 Kpa < Pa02/Fi02 ≤ 40 Kpa with PEEP or CPAP ≥ 5CM H2O (c)


13.3 Kpa < Pa02/Fi02 < 26.7 Kpa with PEEP ≥ 5CM H2O


Pa02/Fi02 ≤ 13.3Kpa with PEEP > 5CM H2O

Abbreviations: CPAP - continuous positive airways pressure, Fio2 - fraction of inspired oxygen,

Pa02 - partial pressure of arterial oxygen, PEEP - positive end expiratory pressure. A - Chest radiograph or computerised tomography
B - If altitude greater than 1000m the correction factor should be as follows: [Pa02/Fi02 x (barometric pressure/760)]

C - This may be delivered non-invasively in the mild acute respiratory distress group.

Absolute contraindications

  • Open abdomen
  • Unstable cervical spine injury

Potential contraindications

  • Raised intracranial pressure
  • Facial or ophthalmic trauma
  • Thoracic wall injury
  • Increased intra-abdominal pressure
  • Extreme obesity
  • Cardiovascular instability
  • Thoraco-lumbar spinal injury
  • Pelvic fracture
  • Recent abdominal surgery
  • 2nd/3rd trimester pregnancy
  • Intra-aortic balloon pump in-situ

Pre-proning considerations and preparation

Consultant intensivist discussion is essential and ideally a bedside review and must be documented clearly in the medical notes.

In LTHT the pressure regulated volume controlled (PRVC) mode on the Maquet ventilator and volume targeted pressure regulated mode (VC+) on the Puritan Bennett are pressure controlled modes which should guarantee a tidal volume whilst minimising peak pressure.

Predicted bodyweight (Devine) calculation;

Men = 50 + 2.3 [height (inches) - 60]
Women = 45.5 + 2.3 [height (inches) - 60].

Predicted bodyweight charts can be found in appendix one. Ventilatory goals include;

  • Deep sedation to Richmond agitation and sedation scale of (RASS) -5
  • Lung protective ventilation which includes tolerating a Pa02 of 8kpa (and perhaps lower in specific situations)
  • Maintaining Pplat <30
  • Titration of appropriate levels of positive end expiratory pressure (PEEP) as referenced in the ARDS net PEEP table (Appendix two)
  • Tidal volumes of 6mls per kg of predicted body weight
  • Tolerating higher than normal Pc02 if the PH is >7.2
  • Consider lengthening the inspiratory time however be cautious of breath stacking (initiation of next mandatory breath prior to the end of the preceding expiratory cycle)

In addition to this consider;

  • Neuromuscular block
    Bolus dose (0.1mg/kg) and then a weight based infusion of atracurium (although other neuromuscular blockers can be used by infusion if indicated). Bispectral index monitoring is advised to guide sedation requirements. If there are concerns over failure of paralysis then consider peripheral nerve stimulator monitoring.
  • Fluid management/restriction
    This can be achieved using a diuretic bolus/infusion, rationalising infusions and/or continuous veno-venous haemodiafiltration (CVVHD) targeting at least neutral balance, ideally negative if the cardiovascular profile allows. This may require an increase in vasopressor support.
  • Recruitment manoeuvres
    In patients who have ‘recruitable alveoli’ this can be a life saving intervention however beware cardiovascular collapse even in patients who appear to have relative cardiovascular stability.

Caution in turning a patient prone too early. Take time to establish invasive lines, carry out other essential procedures, allow other measures time to work (diuresis, muscle relaxant etc.) together with time on the optimal ventilator strategy.

Consultant level decision making includes;

  • Bronchoscopy
    Targeted physiotherapy and positioning are indicated in the first instance.
    Bronchoscopy can treat mucous plugging, lobar collapse and enable direct sampling for microbiology however caution should be exercised as de-recruitment from suctioning and worsening pulmonary infiltrates is common.
  • Referral for ECMO.
    The LTHT pathway is attached in appendix three.

Turning a patient prone

A LTHT video demonstrating the prone positioning is linked here:

This is a manoeuvre that carries risk for both patient and staff.

There is often a period of de-stabilisation following proning and consultant intensivist presence is advised.

All staff should have appropriate training and competency in patient movement.

The prone positioning checklist should be used (Appendix three).

  • Utilise the prone positioning checklist
  • Replace anchor-fast device with conventional endotracheal tube ties
  • Assemble staff
  • Minimum of five staff trained in turning patients prone, one of which is the dedicated airway practitioner
  • This number should be increased according to patients size, physiological stability, staff experience level and difficulty anticipated
  • The airway competent practitioner coordinates the timing of the turn
  • Place a slide sheet beneath the sheet the patient is lying on
  • Position patients arms to their sides
  • Remove all non-essential monitoring (discusswith medical team)
  • Disconnect NG tube and aspirate gastric contents
  • Disconnect all non-essential IV infusions taking extreme care with sterility
  • Position pillows across the patienrs chest, pelvis and knees - leaving the abdominal area free
  • Place a second sheet on top of the patient and match all four corners of both sheets ensuring the patienrs face is uncovered (sand wich technique)
  • Staff on each side of the bed should roll the long edges of the sheets together tightly to cocoon the patient between them
  • Each member of the turning group must wait for the specific instructions at each stage of the turnuUsing the sandwich slide the patient away from the ventilator
  • Turn the patient into a lateral position towards the ventilator, maintaining the tightness of the sheets
  • Pause to check airway, lines, allow for change of hand position and team coordination
  • Staff on each side of the bed should then carefully swap hand position
  • On the instruction ofthe airway person the patient is slowly lowered into the prone position
  • The patient should be fairly central in the bed
  • The abdomen should 'hang' between the chest and pelvic pillows
  • Confirm position of airway
  • Re-establish monitoring and reconnect infusion lines and enteral feed
  • Lower limbs should be apart
  • Reposition the patient's arms into the swimmer's position, alternating the arms every 2-4 hours.
  • Support the upper arm between the shoulder and elbow and lower arm between the wrist and elbow. Avoid pulling onthe patient's wrist.
  • Place a rolled towel in the palm of the uppermost hand.
  • Once in prone position, place the bed at 15-20° foot down (reverse Trendelenburg) to minimise facial oedema and minimise risk of aspiration
  • Check pressure areas including male genitalia, breasts, eyes, lips and ears
  • The prone position can be modified to ¾ facing right and left with pillows supporting the uppermost side.

Ongoing care whilst a patient is prone

Risk of ocular pressure trauma

  • Ensure eyes are closed and free from direct pressure
  • Perform regular eye care
  • Consider use of jelperm over the eyes

Gastric emptying alteration

  • Amend care plan as needed and increase frequency of aspiration to 4 hourly

Facial oedema

  • Use the reverse trendelenburg position

Risk of pressure trauma to anatomical prominences

  • Adapt Plan of care for pressure ulcer care to account for additional risks
  • Ensure ankles are positioned in neutral using support where necessary to avoid excessive toe-down positioning
  • Liaise with physiotherapist for advice regarding positioning and passive range of movement exercises

Cardiac arrest in the prone position

Due to the critical nature of their condition patients may suffer cardiac arrest in the prone position. Significant delays can occur whilst appropriate and sufficient staff members assemble to return the patient supine.

There is no immediate need to turn the patient supine and doing so hastily may be hazardous posing a risk to both losing the patients airway and indwelling lines/tubes and delaying defibrillation and the initiation of CPR.

The following is adapted from the guidelines published jointly by the Neuro- anaesthesia Society of Great Britain and Ireland and the Resuscitation Council (2014).

The immediate priorities are:

  • Confirm cardiac arrest
  • Commence CPR with a conventional technique just lateral to the patient’s left of the thoracic spine. Consider placing two hands under the patient to support the sternum during CPR (See photos below)
  • Summon senior medical and nursing assistance immediately
  • Ventilate the lungs with 100% oxygen using either the ventilator or a mapleson-c circuit/self-inflating bag (caution precipitating alveolar collapse and de-recruitment)
  • Follow standard ALS algorithms  - defibrillation and transcutaneous pacing can be performed prone (see photos)
  • Particular attention should be paid to - Endotracheal tube kinking
    Displacement of the endotracheal tube either out of the airway or down a main bronchus
    The patient has not become disconnected from the ventilator
    Intercostal drains that may have become obstructed
  • Senior medical staff at the bedside will make the decision if and when to return supine and this will be performed as previously described with as minimal disruption to monitoring as possible
  • Commence CPR with a conventional technique just lateral to the patient's left of the thoracic spine.
  • Consider placing two hands under the patient to support the sternum during CPR
  • Suggested placement of pads for pacing and shocks delivery whilst prone

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Appendix 1 & 2

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Appendix 3

Murray Score: taking the score for each variable and divide by 4

Score values:

Murray Score
on 100% O2
≥40 kPa
300 mmHg
30-40 kPa
225-299 mmHg
23-30 kPa
175-224 mmHg
13-23 kPa
100-174 mmHg
<13 kPa
<100 mmHg
CXR Quadrants
(cm H2O

Murray score > 3 may be eligible for ECMO

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Appendix 4


Record: 5510

To promote a stepwise strategy for the management of refractory hypoxemic respiratory failure in ventilated adult patients which includes the process of turning a patient prone together with specific nursing and medical considerations once a patient has been turned prone.

Clinical condition:
Target patient group: Ventilated adult patients with refractory hypoxemic respiratory failure secondary to acute respiratory distress syndrome in critical care.
Target professional group(s): Allied Health Professionals
Secondary Care Doctors
Secondary Care Nurses
Adapted from:

Evidence base

Evidence Base:

Gattinoni L et al. (2001) ‘Effect of prone positioning on the survival of patients with acute respiratory failure’. New England Journal of Medicine, 345 (8), pp. 568-273.

Guérin, C. Reignier J, Richard J.C, et al. (2013) ‘The PROSEVA Study Group. Prone Positioning in Severe Acute Respiratory Distress Syndrome’. New England Journal of Medicine, 368, pp. 2159-2168.

Henderson, W.R., Griesdale, D.E.G, Dominelli, P, and Ronco, J.J.  (2014). ‘Does Prone Positioning Improve Oxygenation and Reduce Mortality in Patients with Acute Respiratory Distress Syndrome?’  Canadian Respiratory Journal, 21 (4), pp. 213-215.

Ranieri, V.M et al. 2012  ‘Acute Respiratory Distress Syndrome: The Berlin Definition’. The Journal of the American Medical Association, 307 (23), pp. 2526-2533.

Kallet, R.H. (2015) ‘A Comprehensive Review of Prone Position in ARDS’. Respiratory Care, 60 (11), pp. 1660-1687.

Neuro-anaesthesia Society of Great Britain and Ireland and the Resuscitation Council UK. 2014. Management of Cardiac Arrest During Neurosurgery in Adults. Available online: content/uploads/2015/03/CPR_in_neurosurgical_patients_resus_council.pdf

Papazien et al. (2010) ‘Neuromuscular blockers in early acute respiratory distress syndrome’. The New England Journal of Medicine, 363 (12), pp. 1107-1116

Approved By

Trust Clinical Guidelines Group

Document history

LHP version 1.0

Related information

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