This document discusses recruitment maneuvers for mechanically ventilated patients. It begins with a case study of a patient presenting with respiratory failure. It then provides definitions and the physiological rationale for recruitment maneuvers, including how alveolar collapse occurs in ARDS. Different types of recruitment maneuvers are described, as well as factors that influence their effectiveness. Clinical trials on recruitment maneuvers are summarized, which found no significant reduction in mortality but some improvement in secondary outcomes. Limitations of recruitment maneuvers are discussed, such as potential hemodynamic effects. The document concludes with emphasizing the complexity of lung recruitment and ongoing controversies regarding recruitment maneuvers.
2. Case Scenario
A 23yr female student by occupation
presented with febrile illness of 4days, h/o
sore throat, cough present, no h/o travel, h/o
breathlessness 1day
o/e
Sensorium normal
Lungs: rr-40/mt, Spo2: 55% on NRBM
Hemodynamics: stable
ABG: type 1 resp failure (po2=25)
Intubated in EMR & shifted to CCU
5. Introduction
Mechanical Ventilation as an essential
supportive measure
“Lung protective” approach
DrawbackARDS
work. NEJM
0; 342:1301-08
Gajic et al VALI in
pt’s with no lung
ALI . CCM
2004; 32:1817-24
7. Definition
Recruitment:
“ aeration of un-aerated alveoli”
Recruitment Maneuver / Re-expansion
Maneuver:
“ denotes the dynamic process of an
intentional transient increase in trans
pulmonary pressure aimed at opening unstable
airless alveoli leading to increase in EELV,
even if it is inadequate to result in effective
alveolar recruitment ”
Pelosi et al,
Review article
Critical Care
2010; p1 - 7
12. Opening and Closing Pressures
50
Paw [cmH2O]
0 5 10 15 20 25 30 35 40 45 50
0
10
20
30
40
Opening
pressure
Closing
pressure
“High pressures may be needed to open some lung units,
but once open, many units stay open at lower pressure”
%
Crotti et al
AJRCCM 2001
21. Anatomical Recruitment
No recruitment PEEP + 5 40 cm recruitment + PEEP above LIP 60 cm recruitment PEEP + 25AJRCCM 2006;174: 268 – 78.
26 patients
Slide Courtesy: Dr. Ram Echambadi Rajagopalan
23. Monitoring The Efficacy
Malbouisson et al
PEEP-RM / CT
AJRCCM 2001;
163:1444-50
Richard JC et al
Role of PEEP & RM
AJRCCM 2001;
163:1609-13
Enrique & Vilagra
Effects of RM
CC Forum
2004; 8:115-121
ATS
loop C: Sustained inflation on
high PEEP favored alveolar
over-distension
24. Interpreting the PV Curve
Measurement is not practical clinically
A single inflation probably does not provide useful information
to determine safe ventilator settings
Whole lung P/V curve is a composite of multiple regional P/V
curves (LIP varies widely)
Kunst PW et al
CCM 2000
25. PaO2 improves
No change EVLW
Decrease in
atelectasis rather
than EVLW
Change in CI -
Significant
Continuous Scvo2
Changes in CVP, HR
& MAP - insignificant
Tamas Leiner et al
CCM 2007;
Vol 35,
No.3
n = 18
26. Viviane R. S,
MD ;et al
CCM 2010;
Vol. 38, No 11
n = 36
40 cm/40secAnaesthesia, NMB
& Protective Ventilation
ABG &
Lung mechanics
ABG &
Lung mechanics
27. After RM,
Static lung elastance & alveolar collapse
lung, liver, and kidney cell apoptosis, and
type 3 pro-collagen and interleukin-6
mRNA expressions
Electron microscopic images of lung
parenchyma were assessed
Alveolar edema is seen only in severe
ALI
Alveolar collapse were similar in both
ALI groups
Viviane R. Santiago,
MD ;et al
CCM 2010;
Vol. 38, No 11
28. Conclusions
RM seems to promote modest but
consistent increase
alveolar stress & inflammation
fibrogenic responses
worsening lung function &
potentiating injury to alveolar and kidney
epithelium
lower in moderate ALI than in severe
ALI
IL-6
Type 3 Collagen
30. Factors Influencing The Response
Non uniformity & Variable outcome
Underlying lung disease
Baseline ventilation & volume history
Duration of Illness
Prone position
Type of RM & Post-recruitment PEEP
31. Underlying lung disease
Douglas R.Riva et al
CCM 2008;
Vol.36 163:1900-08
Malbouisson et al
PEEP-RM / CT
AJRCCM 2001;
163:1444-50
“more effective at opening collapsed alveoli in extra-
pulmonary ARDS, thus improving lung mechanics,
oxygenation, with limited damage to alveolar epithelium”
32. Underlying lung disease
Douglas R.Riva et al
CCM 2008;
Vol.36 163:1900-08
Malbouisson et al
PEEP-RM / CT
AJRCCM 2001;
163:1444-50 “greater PCIII mRNA expression in ALI pulmonary”
RILI
33. Baseline ventilation & “Volume history”
Proportion of atelectatic lung
Ventilatory settings that promote
derecruitment
Volume history: time dependant
manner
Bates JH et al
Time dependency;
Theoritical model
Journal of
Physiology 2002
Vander Kloot et al
RM in oleic acid
injury model
AJRCCM 2000;
161:1949-56
34. Duration of Illness
“Less is More” & “More is Less”
Less compliance of Lung & Chest
wall
Grasso S et al
Anesthesiology
2002; 96: 795-802
35. Prone position
RM by itself
“Mule” or Complimentory effect
No incerase in EELV
Makes lung expansion more uniform
by the attenuation of heterogeneous
compressive forces
Pelosi et al
AJRCCM
2003; 167: 521-527
36. RM type & Post-RM PEEP
Evidence little for type of RM
Animal experiments
Pressure targeted appears promising
Post recruitment PEEP level – most
important determinant to prevent RACE
Lim et al
CCM
2003; 167: 521-527
38. EXPRESS TRIAL
A RCT : JAMA 2008
768 patients, RCT
Minimal distension:
PEEP & Plat : as low as possible
Without affecting saturation targets
Increased Recruitment group:
“PEEP titration based on Plateau”
Oxygenation is not the goal
L. Brochard
39. EXPRESS TRIAL
A RCT : JAMA 2008
Conclusion:
“strategy aimed at increased alveolar
recruitment while limiting hyperinflation didn’t
significantly reduced mortality”
Better lung mechanics
Reduced duration of MV
Reduced duration of organ failure
Post hoc analysis:
“ ALI may be associated with less benefits &
more adverse effects from high levels of PEEP”
L. Brochard
40. Lung Open Ventilation Study
JAMA 2008
985 pts enrolled, RCT
Control group: protective ventilation
Volume Control
Experimental group:
PC mode + RM (40/40) + Pplat 40
Tidal volumes were similar
Mean PEEP : 10 Vs 15 in first 72hrs
Barotrauma rates were similar
41. Lung Open Ventilation Study
JAMA 2008
Conclusion:
“open strategy did appear to
improve secondary end points related
to hypoxemia & use of rescue
therapies”
Low rates of
Refractory hypoxemia,
Death with refractory hypoxemia &
Need of “Rescue therapy”
44. In a nut shell……….
Hemodynamic compromise
Intracranial blood flow
VILI / RILI
Bacterial translocation
Clinical benefits ????
45. Hemodynamic Effects
Lung inflation by positive pressure causes
Increased pleural pressure and impeded venous return
Increased pulmonary vascular resistance
Compression of the inferior vena cava
Retardation of heart rate increases
These effects are much less obvious in the presence of
Adequate circulating volume
Adequate vascular tone
Spontaneous breathing efforts
Preserved adrenergic responsiveness
46. “With More Lung Compliance, High Levels of
PEEP are Generally Not Well Tolerated”
Hemodynamic Effects
47. Capillaries in the alveolar walls undergo compression even
as interstitial vessels dilate. The net result is usually an increase
in pulmonary vascular resistance, unless recruitment of collapsed
units occurs.
Hemodynamic Effects
On Pulmonary vasculature:
49. Summary………..
Transient increase in trans pulmonary
pressure to increase in EELV
“Lung protective strategy”
Bio-trauma facilitates MODS
ARDS – commonest indication
Prerequisites
CPAP – most widely studied & PEEP
titration in PC mode is user &
hemodynamic friendly
50. Summary………..
Pao2 is a surrogate marker for monitoring
Continuous Scvo2 & CCO monitor is
recommended as CVP is poor predictor of CI
RM worsens the inflammation in Pulmonary ALI
Volume history is important before attempting a
RM
Prone has complimentary effect
Titrate PEEP based on compliance &
oxygenation
51. Summary………..
Studies
Did not reveal any mortality benefits
Did appear to improve secondary end points &
its role as rescue therapy
Adverse events
Hypotension & Arrhythmias
Barotraumas & De-saturation
52. Controversies
Which patients will benefit?
How long to recruit?
What is optimum level of Post
recruitment PEEP?
When to use: routine or only during
hypoxic episodes?
54. Diseased Lungs Do
Not Fully Collapse,
Despite Tension Pneumothorax
…and
They cannot always
be fully “opened”
Dimensions of a fully
Collapsed Normal Lung
Notes de l'éditeur
Just recollect my memories, when I was working at SMF
1. Through out the presentation, I will be mentioning RM as RM
An aim to increase EELV
Froesse: Effects of anesthesia & paralysis on diaphragmatic mowements in man. Tendency of caudobasal segmental collapse ewen in normal lungs in periop period.
Maggaire: prewention of ET-suction induced alweolar derecruitment in ALI. Repaeted ET Suctioning & high fi02 requirements- commonly seen in wentilated patients – promote absorption atelectasis.
Ranieri: effect of MW on inflammatory mediators in pts with ARDS, A RCT.
Rimsenberger (Not mentioned abowe), Open lung during small tidalwolume wentilation : concepts of optimal peep & recruitment CCM 1999. He stated clearly that, “As the lewel of applied peep to keep recruited lung open may be lower than that required to open up atelectatic segments”.
Definitions:
Stress: During MV, spatial rearrangement if fibres occurs due to Trans-pulmonary pressure.
Strain: During MW, elongation of fibres leads to dewelopment of strain.
These fibres hawe a wariable capacity to elongate & when stress exceeds the capacoty of the fibres to stretch, the fibres rupture leading to Baro trauma.
Volutrauma occurs when strain is not high enough to rupture the fibres.
B. MSOF is the result
Tissue injury secondary to inflammatory cells/mediators
Impaired oxygen deliwery
??? Bacteremia
1.% of collapsed tissue decreased from 63% at ZEEP to 29% after open lung approach & after RM to 5%.
2. Simillarly P/F increased from 92% (ZEEP) to 250 (after open lung approach) & after RM to 400.
Computed tomography quantification of collapsed tissue and PaO2/FIO2 ratio obtained with
different recruitment maneuvers in acute respiratory distress syndrome patients. PPLAT, plateau
pressure; ZEEP, zero end-expiratory pressure. From Borges (33)
P/F Ratio from ATS. There are studies where they studied, role of Paco2 and dead space assessment as a measure of recruitment.
Malbouisson et al, “ CT assessment of PEEP induced Alveolar Recruitment”, showed a significant correlation bwn PEEP induced RM and improwed arterial oxygenation when recruitment was assessed by the volume of gas entering nonaerated or poorly aerated areas of the lung as seen on CT scans.
Richard et al : “ Influence of tidal volume on Alv Recruitment: Respective role of PEEP & a RM”. Upward shift of the Static PV curve as well as chest wall & lung elastance
Dynamic loops during three modes of ventilation inscribed into the quasistatic pressure–volume curve of the respiratory system of an animal after lung washes. Loop A: tidal insuflation with a positive endexpiratory pressure (PEEP) below the lower inflection point before a sustained inflation. Loop B: tidal insuflation with a PEEP below the lower inflection point after a sustained inflation. Loop C: PEEP higher than the lower inflection point after a sustained inflation. Sustained inflation promoted alveolar recruitment at low PEEP levels (loop B). Sustained inflation superimposed on high PEEP favored alveolar overdistension in this model of surfactant depletion (loop C).
Paraquat model ws saline intraperitoneally
Single RM CPAP PS 40/40 f/b 1hr protectiwe wentilation.
Apologies for B&W pictures instead of H&E stained
Electron microscopic images of lung parenchyma in control and in moderate and severe
acute lung injury groups with recruitment maneuver or not (nonrecruited). Moderate acute lung
injury showed cytoplasmatic degeneration of type 2 pneumocytes and endothelial injury, whereas in
severe acute lung injury alveolar epithelium and endothelium presented further damage. In the
control–nonrecruited group, type 2 cells were well preserved, with typical microvilli projecting from
the surface. Note the integrity of the alveolar capillary membrane. A recruitment maneuver led to the
detachment of alveolar epithelium in moderate acute lung injury (ellipse), which was more pronounced
in severe acute lung injury (arrows).
Apologies for B&W pictures instead of H&E stained
Electron microscopic images of lung parenchyma in control and in moderate and severe
acute lung injury groups with recruitment maneuver or not (nonrecruited). Moderate acute lung
injury showed cytoplasmatic degeneration of type 2 pneumocytes and endothelial injury, whereas in
severe acute lung injury alveolar epithelium and endothelium presented further damage. In the
control–nonrecruited group, type 2 cells were well preserved, with typical microvilli projecting from
the surface. Note the integrity of the alveolar capillary membrane. A recruitment maneuver led to the
detachment of alveolar epithelium in moderate acute lung injury (ellipse), which was more pronounced
in severe acute lung injury (arrows).
Real-time polymerase chain reaction
analysis of interleukin-6 and type 3 procollagen
mRNA expressions of rat lung tissue in control
and in moderate and severe acute lung injury
groups with recruitment maneuver or not (nonrecruited).
There was an initial enthusiasm for benefits of RMs, but studies indicated that the improvement of oxygenation & duration of benefit are widely variable.
RMs are more
effective at opening collapsed alveoli in
an experimental model of ALIexp than in
ALIp, thus improving lung mechanics
and oxygenation, with limited damage to
alveolar epithelium.
Pt managed with went settings that promote derecruitment will respond fawourably by increasing EELW & oxygenation after a RM. This is clearly indicated wander klloot study. They were unable to demonstrate benefits from a RM in animals wentilated with a PEEP of 20cms & a tidal wolume of 15ml/kg in contrast with lower PEEP and tidal wolume. This suggest that the a.w. pressures in the former group are sufficiently high enough recruit most recruitable lung units & we cant expect additional benefit from RM.
Wolume H/O: Low WT & Low PEEP cause collapse of the a.w. in a time dependent manner. Its imp to recognise that mechanics of the lung is not only influenced by the wolume of gas in it or the pettern of flow of gas, but also how this lung wolume has been alterd ower a period of time.
Both animal studies & studies in ARDS patients reweals, RMs are more effectiwe in Prone position.
Pelosi study : An Intermittent sigh was noted to transiently open up collapsed units as indicated by some improwement of oxygenation & a small increase EELW in supine pt. When they repeated RMS in prone patient, significant increase in oxygenation & EELW.
Conclusion: They work together, PP & RM hawe a complimentary action as they work by different mechanisms. i.e.a. Prone: no incease in EELW, makes lung expansion more uniform by the attenuation of heterogenous compressiwe forces
Lim et al compared bwn PC (45/16) RM / CPAP (45 for 40sec) & Incremental PEEP (upto 35cms maintaining Ppeak <35cms H20) in animals with VILI & they observed best response in PC RM.
The emphasis of the study was however that the most imp determinant of efficacy was the level of post Rec PEEP applied to Pv RACE
Rewerse trend obserwed in ARDS from low lewels of PEEP
Total 248 articles awailable online.
Which pts will benefit whether Pulm ARDS or EP ARDS