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521 Lung Recruitment Maneuver for Severe Hypoxemia and ARDS 521/ Page 1 of 5 Description Acute respiratory distress syndrome (ARDS) is characterize...
Author: Matilda Douglas
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521

Lung Recruitment Maneuver for Severe Hypoxemia and ARDS

521/ Page 1 of 5

Description Acute respiratory distress syndrome (ARDS) is characterized by altered permeability pulmonary edema and low lung compliance. Often ARDS is complicated by decreased chest wall compliance as well. This results in decreased lung volume (de-recruitment) and hypoxemia. Approximately 15-20% of patients with ARDS exhibit extreme, severe hypoxemia refractory to both high inspired oxygen fractions (Fi O2 ) and positive end-expiratory pressure (PEEP). In this sub-group of patients extraordinary measures (i.e. Recruitment Maneuver) are required to recruit collapsed lung tissue and stabilize gas exchange. These measures include high, static, inflation pressures of 40-50 cm H 2 O for 40 seconds duration, followed by a trial of Super PEEP (i.e.: > 20 cm H 2 O), and a PEEP decrement trial based upon arterial blood gas results. Indications for Recruitment Maneuver (RM) Severe Refractory Hypoxemia

Guideline: Recruitment Maneuver should be considered when: a stable Pa O2 of 60-80 mm Hg cannot be maintained on a Fi O2 >0.70 with a PEEP of >16 cm H 2 O. A stable Pa O2 is defined as the absence of large drops (> 10 mmHg) between blood gas measurements and/or the absence of significant prolonged desaturations ( > 5% for > 5 min) associated with basic patient care (i.e.: repositioning, closed endotracheal tube suctioning, line placement, etc.). There is no consensus regarding when Recruitment Maneuvers should be instituted. However, many patients with ARDS respond well to relatively high levels of PEEP(14-16 cm H 2 O) with a lung-protective V T of 5-7 mL kg. Often this is sufficient allow Fi O2 to be decreased to a relatively safe level (< 0.70). The above stated indications for Recruitment Maneuver suggest an inability to provide stable oxygenation during transient periods of stress (e.g.: hypotension/shock, intra-hospital transport, procedures), as well as an excessive risk of lowvolume lung injury (i.e.: “atelectrauma”). Contraindications



Shock: Mean arterial pressure < 60 mm Hg



Barotrauma: Presence of pneumothoraces, pneumomediastinum, pneumopericardium, pneumatoceles, or subcutaneous air.



Unilateral or focal lung disease



Necrotizing lung disease, Cavitary Lesion



Chest radiogram suggestive of hyperinflation



Presence of bullous lung disease



Traumatic Brain Injury (unless approved by Neurosurgery/Neurology)

RCS SFGH

reviewed 1/10, 11/10

revised 1/10, 3/13

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Lung Recruitment Maneuver for Severe Hypoxemia and ARDS

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Preparation for the Recruitment Maneuver

Clear communication with physician and nursing staff must occur prior to carrying out the Recruitment Maneuver delineating each staff member’s roles and responsibilities. Attending Approval: Initiation of a Recruitment Maneuver must have the approval of an ICU attending physician. Careful consideration should be given to balancing the likelihood of gas exchange benefits and with potential risks in individual patients. Physician Presence: An ICU resident or fellow must be present at the patient’s bedside during the initial RM and to supervise situations that require multiple Recruitment Maneuvers with adjustments in CPAP level and post-RM settings of PEEP. Furthermore, when the ICU physician determines the necessity of instituting Recruitment Maneuver therapy in the setting of hemodynamic instability (see below), a senior member of the team must be present at the bedside. Cardiovascular Support: It is the responsibility of the ICU physician to evaluate hemodynamic status prior to initiating a Recruitment Maneuver, and to initiate, or make any adjustments in vasopressor and/or fluid therapy to promote tolerance of the procedure. The ICU team should have a pre- Recruitment Maneuver plan of action communicated to both nursing and respiratory care personnel on how to deal with the possibility of inadvertent cardiovasacular instability (e.g.: initiating or adding vasopressors, increasing vasopressor dosage, administering fluid boluses, transient PEEP decrement or some combination). This is particularly important in situations that require multiple Recruitment Maneuvers with adjustments in CPAP level and post-RM settings of PEEP. It is recommended that minimum baseline values prior to commencing a Recruitment Maneuver include a systolic BP > 90 mmHg, a MAP > 60 mmHg and a heart rate < 140. Nursing Presence: The ICU nurse who is primarily responsible for the patient’s care should be aware of the Recruitment Maneuver plan. An RN should be present at the bedside to assist with monitoring of the patient during the peri- Recruitment Maneuver period and to execute any needed changes in supportive care. Sedation Strategy: Given the magnitude and acute nature of intrathoracic pressure changes that occur with a Recruitment Maneuver, it is important to eliminate patient-ventilator asynchrony as a contributing factor to a patient’s severe hypoxemia, and therefore, the need for a Recruitment Maneuver. Moreover, both patient safety during and maximal efficacy of a Recruitment Maneuver requires that the patient’s sedation should be adjusted to achieve passive ventilation and a Ramsey Score of 5-6, or a RASS of -4 or -5. Spontaneous breathing efforts during a Recruitment Maneuver may increase the risk of barotrauma and promotes alveolar derecruitment (i.e.: active expiratory efforts decreases chest wall compliance). Use of neuromuscular blocking agents is at the discretion of the ICU physician team. The ICU nurse who is primarily responsible for the patient’s care should be aware of this plan. RCS SFGH

reviewed 1/10, 11/10

revised 1/10, 3/13

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Lung Recruitment Maneuver for Severe Hypoxemia and ARDS

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Physician's Order A pre-printed physician order sheet specifying the CPAP and post-recruitment management strategy must be used. Procedure The initial Recruitment Maneuver is to be treated as a special procedure in the same manner as an intubation. The respiratory care practitioner executing the procedure must be relieved of all other clinical responsibilities until the procedure is completed, the patient’s condition is stable both in terms of hemodynamic and respiratory status and the procedure has been documented. 1. Sedation should be adjusted to Ramsey Scale value of 5-6 / RASS -4 to -5. 2. Perform a baseline ventilator systems check including arterial blood gas (ABG) and Vd/Vt measurement. 3. Increase the Fi O2 to 1.0 for at least 5 min. (Note: Under some circumstances, physicians may wish to monitor Sp O2 response during the Recruitment Maneuver and ask that Fi O2 be adjusted to achieve a baseline Sp O2 of approximately 95%. This is permissible.)

4. Note the baseline heart rate, rhythm, blood pressure and Sp O2 . 5. Change the ventilator mode to CPAP of 20 cm H 2 O or baseline PEEP level (whichever is higher). 6. Increase CPAP in steps of approximately 10 cm H 2 O every 10sec until the target of 40 cm H 2 O is reached. (Note: As soon as the change in CPAP is confirmed, immediately adjust to the next level. Don’t wait. High levels of CPAP require re-confirmation at steps of 20, 30 and 35 cm H 2 O. Therefore, making continuous upwards adjustments/confirmations in CPAP will consume at least 10 sec/step.)

7. Hold CPAP at 40 cm H 2 O for 40 sec. 8. Initiate alarm silence; use the alarm countdown clock display to time the 40 sec sustain. 9. Decrease CPAP in steps of 10 cm H 2 O every 10 sec to a Post Recruitment Maneuver target PEEP level 20-26 cm H 2 O based on ICU physician order. 10. Reinstitute continuous mandatory ventilation (CMV) and previous settings but at a PEEP of 20-26 cm H 2 O according to ICU physician order. (Note: Post Recruitment Maneuver Fi O2 should be the same as baseline work-up to assess efficacy). 11. Repeat ventilator systems check with arterial blood gas and Vd/Vt measurement between 15-30 min after the initial Recruitment Maneuver.

RCS SFGH

reviewed 1/10, 11/10

revised 1/10, 3/13

521

Lung Recruitment Maneuver for Severe Hypoxemia and ARDS

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12. If the post- Recruitment Maneuver arterial blood gas and Vd/Vt measurements show either satisfactory or substantial improvement, the ICU physician should direct the respiratory care practitioner to follow one of the following actions: a. Return to baseline Fi O2 and initiate PEEP-decrement trial. i. PEEP-Decrement Trial: the standard procedure is to wean PEEP in 2 cm H 2 O steps over a specific time increment (in hrs). The time increments are arbitrary and should be based upon the magnitude of improvement in oxygenation (e.g.: more rapid decrements should occur when there are substantial improvements in Pa O2 whereas, slower PEEP decrements should occur when improvements in Pa O2 are modest) Note: PEEP decrement trials must specify both a minimal target Pa O2 and a minimal PEEP level that can be reached before the ICU physician reassess the patient.

ii. Once the Pa O2 decreases below this target, then repeat the Recruitment Maneuver at the previous CPAP level. (Note: This particular Recruitment Maneuver may be done independently by respiratory care practitioners without physician presence at the bedside if there are no safety concerns such as cardiac or hemodynamic instability.) iii. After the Recruitment Maneuver is repeated, the new PEEP should be set 2 cmH 2 O above the PEEP at which Pa O2 < minimal target). b. Maintain PEEP and reduce Fi O2 to a new specified target (i.e.: different than preRecruitment Maneuver baseline Fi O2 ) prior to initiating PEEP decrement trial). c. Return PEEP/Fi O2 to baseline settings d. Return to ARDS Net PEEP/Fi O2 strategy 13. If the Recruitment Maneuver does not achieve the desired minimal improvement in Pa O2 , then the ICU physician has the option to: a. Discontinue Recruitment Maneuver procedures. b. Repeat the Recruitment Maneuver at the same and/or increasing CPAP levels of 45, and 50 cmH 2 O. Therefore, the Recruitment Maneuver may be repeated up to 3 times/session. 14. When multiple Recruitment Maneuvers are done at escalating levels of CPAP, a full assessment with complete ventilator systems check, ABG and Vd/Vt measurement should be repeated at 15-30 min following each step 15. After the final Recruitment Maneuver, the ICU physician has the option to: a. Wean the Fi O2 to a desired target and then initiate a PEEP-decrement trial. b. Maintain the post-Recruitment Maneuver PEEP level and titrate Fi O2 . RCS SFGH

reviewed 1/10, 11/10

revised 1/10, 3/13

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Lung Recruitment Maneuver for Severe Hypoxemia and ARDS

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c. Resume ARDS Net PEEP/Fi O2 titration orders. d. Resume pre-Recruitment Maneuver ventilator settings and titration orders Note: For patients managed with the ARDS Net Protocol, the PEEP/Fi O2 orders should be re-written to document changes in management based upon Recruitment Maneuver results.

Complications A review of the current literature (2009) found that the primary complication of the CPAP method for Recruitment Maneuver is hypotension (usually mild) and paradoxical oxygen desaturation that resolves with discontinuation of the procedure. The frequency of these complications is approximately 10% in study patients. However, more serious complications such as shock, cardiac arrthymias and pneumothoraces have been reported. The Recruitment Maneuver should be aborted immediately if any of the following occur: •

Decrease in mean arterial pressure (MAP) > 10 mm Hg



MAP < 60 mmHg



Decrease in Sp O2 > 5%



Change in heart rate > 20



Appearance/increase in cardiac arrhythmias.

Charting The Recruitment Maneuver procedure is to be documented in the RCS flow sheet in the parameters section: Vent Mode is charted as CPAP with the appropriate pressure level of PEEP and Fi O2 used. A comment should be included with the highlighted mode change identifying it as an Recruitment Maneuver. Also chart the Outcome, Events, and Duration (in seconds) under the Recruitment Manuever parameter row, identifying any change (or lack of change) in blood pressure, heart rate, presence of arrhythmias, and Sp O2 during the procedure or immediately afterwards. Any and all complications (and their treatment) are to be documented in further detail in the RCS notes section as a “critical event” and summarized in the “end-of-shift” notes. Charges The patient should be charged for each Recruitment Maneuver performed.

RCS SFGH

reviewed 1/10, 11/10

revised 1/10, 3/13