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Recruitment Manoeuvres

Recruitment Manoeuvres. for the improvement of oxygenation. Alex Yartsev 09/02/2010. Recruitment Manoeuvres. An administration of high ventilation pressure to a patient for a brief period of time Aim is to reinflate collapsed lung tissue, thus “recruiting” that tissue

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Recruitment Manoeuvres

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  1. Recruitment Manoeuvres for the improvement of oxygenation Alex Yartsev 09/02/2010

  2. Recruitment Manoeuvres • An administration of high ventilation pressure to a patient for a brief period of time • Aim is to reinflate collapsed lung tissue, thus “recruiting” that tissue • Aim is also to prevent “de-recruitment” by applying PEEP after the manoeuvre • The desired outcome is improved oxygenation • There are specific indications

  3. When do you need RM • BROADLY: when the patient has enough collapsed alveoli to impact on their oxygenation

  4. The physiology • There are both inflating and collapsing forces acting on the alveoli: • COLLAPSING: • Surface tension • Recoil pressure of the lungs • +1cmH2O alveolar pressure (expiration) • Gas absorption • INFLATING: • Surfactant • Negative pleural pressure • -1cmH2O alveolar pressure (inspiration) • Nitrogen splinting

  5. Causes of alveolar collapse • Loss of surfactant eg. ALI/ARDS • Positive pleural pressure eg. pneumothorax • Negative alveolar pressure eg. suctioning • Gas reabsorption eg. sputum plugging • Loss of nitrogen splinting eg. high FiO2

  6. Indications for RM • ARDS / Acute Lung Injury • Patients with “secondary ARDS” (eg from abdominal sepsis) seem to respond better than those with “primary” ARDS eg. from pneumonia • Bilateral pulmonary infiltrates • PaO2/FiO2* <300 = ALI • PaO2/FiO2 <200 = ARDS • Atelectasis during general anaesthesia • After suctioning the ETT

  7. Contraindications for RM • Hemodynamic compromise: recruitment manoeuvres cause a transient loss of venous return, compromising cardiac output. • Existing barotrauma • Increased intracranial pressure • Predisposition to barotrauma: • Apical bullous lung disease • Focal lung pathology eg. lobar pneumonia

  8. Determining the “recruitability” of lungs • CT scans on low and high PEEP: compare the volume of aerated regions (Gattinoni 2006) • Effect of PEEP: compare PEEP 5 and PEEP 15; the change in the percentage of nonaerated lung tissue is correlated with the percentage of potentially recruitable lung – and can be calculated from the changes in PaO2/FiO2 ratio (Maggiore 2001) • Pressure- volume curves: oversimplify the situation; heterogeneity of lung tissue in an ARDS lung does not lend itself well to being reduced a single curve

  9. Types of Recruitment Manoeuvres • CPAP with increased pressures • Pressure-controlled ventilation on high PEEP • Advanced recruitment manoeuvres: • Prone ventilation to recruit dorsal lung units • High frequency oscillatory ventilation (lung protective) • Airway pressure release ventilation, low PEEP and low tidal volume, with I:E of 4:1

  10. Aims of recruitment manoeuvres Overdistension, thus Surfactant degradation Mechanical lung injury High oxygen exposure Atelectasis and Derecruitment Thus, Hypoxia VQ mismatch Injury due to repeated opening/closing of alveoli

  11. Consequences of Recruitment Manoeuvres • Increased oxygenation • Stretch reflex of the alveoli, which causes Type II respiratory cells to release more surfactant • Increased intrapulmonary shunt • Barotrauma; overdistension of already well-ventilated lung regions • VILI due to the above • Increased pulmonary arterial pressure • Decreased cardiac output • Increased intracranial pressure • The hemodynamic consequences seem to normalise 10-20mintues after the manoeuvre ( Bein et al 2002)

  12. Some basic RM protocols • CPAP 40cmH2O for 40 seconds (Girgis et al 2006 resp care) • CPAP 40cmH2O for 30 seconds (Brower et al. 2003 crit care med) • Pressure controlled ventilation with Pplat 45cm H2O, PEEP of 5, I:E 1:1 and rate of 10 (Gattinoni et al 2006 NEJM) • Volume control ventilation with 20cmH2O of PEEP, allowing Ppeak to go up to 40cmH2O, for 2 minutes, and then gradually reducing PEEP (Celebi et al 2007 Anaesth Analg)

  13. PEEP after recruitment • Everyone seems to agree that appropriate PEEP following recruitment manoeuvres is critical for SUSTAINED improvement • Nobody agrees on how to determine appropriate PEEP • Generally, it is recommended (Hickling 2001) to gradually decrease PEEP until there is a fall in PO2; this is a “decremental PEEP trial” • PEEP is decreased by 2cmH2O every 4 minutes • A fall in PO2 by over 10% indicates that there is derecruitment • PEEP is then set to just above the level at which derecruitment occurs • For Girgis et al (2006) this strategy resulted in 4 hrs of improved oxygenation

  14. Monitoring during RM • Discontinue the manoeuvre if: • Systolic BP decreases by 30mmHg • SaO2 decreases by 5% • Heart rate increases by 20bpm • Arrhythmia is seen

  15. Whats the best RM manoeuvre? • Numerous RM protocols are published • Small numbers, different outcome measures, patient heterogeneity • Decremental PEEP is the only strategy which shows benefit, i.e. prolongs the oxygenation benefit of RMs

  16. Who is most likely to benefit? • Atelectatic post-op patient: normal lung • Ventilated patient who is hypoxic after suctioning • ARDS patient in the early stages

  17. Who is least likely to benefit? • Patient with pneumonia • Primary ARDS (pneumonia, toxic gas inhalation, lung contusion) • Late ARDS, with organization / fibrosis

  18. Do recruitment manoeuvres improve outcomes ?Whats the evidence? • A 2009 Cochrane review by Hodgson et al: • 7 trials reviewed, total N = 1170 • Did not differentiate between different RM strategies, simply compared RM vs no RM in ARDS • No significant difference on 28th day mortality • No statistical difference in risk of barotrauma • RMs did indeed cause significantly improved oxygenation for brief periods, but this was not sustained. • CONCLUSION: “There is not evidence to make conclusions on whether recruitment manoeuvres reduce mortality or length of ventilation in patients with ALI or ARDS.”

  19. In summary: • RMs help in early ARDS, post-op atelectasis, and after suctioning • Not to be used in patients with barotrauma, hemodynamic compromise, bullous lung disease or head injury • Monitor carefully during and after the manoeuvre • Use a decremental PEEP trial to establish minimum effective PEEP • Do not expect long-term gains in oxygenation or lung mechanics

  20. References • Oxford Textbook of Critical Care (CIAP) • Ohs Intensive Care Manual (6th ed.) • Guyton and Hall Medical Physiology (11th ed) • Amato et.al., Lung Recruitment in Patients with the Acute Respiratory Distress Syndrome NEJM volume 354:1775-1786 Number 17 April 2006 • Tusman G, Bohm SH, Vazquez de Anda GF, do Campo JL, Lachmann B (1999) `Alveolar recruitment strategy' improves arterial oxygenation during general anaesthesia. Br J Anaesth 82:8–13 • Meade MO, Guyatt GM, Cook DJ (2002) Physiologic randomized pilot study of a lung recruitment study in acute lung injury. Am J Respir Crit Care Med 165:A683 • Maggiore et al Alveolar Derecruitment at Decremental Positive End-Expiratory Pressure Levels in Acute Lung Injury, Am. J. Respir. Crit. Care Med., Volume 164, Number 5, September 2001, 795-801 • Hodgson et. al., Recruitment manoeuvres for adults with acute lung injury receiving mechanical ventilation. Cochrane Database of Systematic Reviews 2009, Issue 2. Art. No.: CD006667. DOI: 10.1002/14651858.CD006667.pub2.

  21. More references • Bein T, Kuhr LP, Bele S, Ploner F, Keyl C, Taeger K. Lung recruitment maneuver in patients with cerebral injury: effects on intracranial pressure and cerebral metabolism. Intensive Care Med 2002;28:554–558. • Moran et al, Recruitment manoeuvres in acute lung injury/acute respiratory distress syndrome Eur Respir J 2003; 22:37s-42s • Dyhr et al, Lung recruitment manoeuvres are effective in regaining lung volume and oxygenation after open endotracheal suctioning in acute respiratory distress syndrome Critical Care 2003, 7:55-62 • Tusman et al, Alveolar recruitment strategy improves arterial oxygenation during general anaesthesia British Journal of Anaesthesia, Vol 82, Issue 1 8-13, 1999

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