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Tufts-New England Medical Center Weaning Protocol. A Product of the T-NEMC Critical Care Committee October 2004. Tufts-New England Medical Center Weaning Protocol.
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Tufts-New England Medical Center Weaning Protocol A Product of the T-NEMC Critical Care Committee October 2004
Tufts-New England Medical Center Weaning Protocol This is a general guideline and does not represent a professional standard of care governing providers' obligations to patients. Care is revised to meet individual patient's needs" These guidelines do not prohibit or impede the planned rapid weaning and extubation of patients.
Protocol Weaning is More Effective than No Protocol • Numerous studies have demonstrated that protocol weaning decreases mechanical ventilation days. • Vitacca AJRCCM 2001;164:225-30 • Henneman CCM 2001;29:297-03 • Kollef New Horizons 1998;6:52-60 • Kollef CCM 1997;25:567-74 • All studies utilized a daily screening and subsequent spontaneous breathing trial to test the patient’s potential for discontinuing mechanical ventilation.
Protocol Weaning is More Effective than No Protocol The studies listed above all demonstrate that any weaning protocol reduces days of mechanical ventilation when compared to patients not managed by a weaning protocol.The Kollef study from 1997 CCM actually compared three separate ICUs, each using a separate and different protocol to non-protocol weaning of patients. Each protocol resulted in similar days of mechanical ventilation when compared to each other and all three protocols resulted in fewer days of mechanical ventilation than did non-protocol weaning.All protocols studied utilized a nurse/therapist driven process that screened all patients daily and if criteria were met, a spontaneous breathing trial followed.
Sedation: Optimum Levels to Promote WeaningThe Riker Sedation Scale 7 – Dangerous agitation 6 – Very agitated 5 – Agitated 4 – Calm & cooperative 3 – Sedated 2 – Very sedated 1 – Unarousable Levels 3 – 4 are optimal levels for weaning } Over sedation stops the weaning process and should be avoided if possible.
Sedation: Optimum Levels to Promote WeaningThe Riker Sedation Scale • The Riker Sedation Scale is an easy method to assess sedation level. While it lacks some specificity, it can be used to uniformly classify levels of sedation. When used for facilitating weaning, levels of 3 – 4 are targeted.These levels (3 – 4) do not prevent the patient from making spontaneous ventilatory efforts. A fully supported patient receiving high set rates and set tidal volumes may not be triggering the ventilator but when given an opportunity the assume the work of breathing, patients with Riker scores of 3 – 4 will make spontaneous breathing efforts.Careful modulation of sedation to preserve pulmonary function and yet avoid unacceptable agitation and anxiety are critical to successful weaning.
Rapid Shallow Breathing Index (RSBI) The RSBI is a one minute trial of unassisted breathing. It is the most accurate test to predict weaning success. RSBI calculation: RSBI = RR / (MV/RR) Measure RR and MV for 1 minute during unassisted breathing:(0 PEEP/5 cmH20 PSV). At the end of 1 minute divide the MV by RR to calculate the average Vt. Divide the RR by the VT to obtain the RSBI. Spontaneous Breathing Trial (SBT) A SBT is the continuation of unassisted breathing for 30 min. to 2 hours if the RSBI is < 105. After successfully completing a SBT, current studies indicate extubation is generally successful in approximately 75% of patients. Protocol Definitions
Protocol Definitions The methodology chosen to assess the RSBI is based on several points.The use of zero PEEP is chosen for three reasons:1)to determine if the patient will tolerate a reduction in thoracic pressure without developing CHF.2)It demonstrates the adequacy of lung function in maintaining acceptable oxygenation.3)It allows the patient to demonstrate that there is minimal work imposed by trappingConsequently, all RSBI tests as well as Spontaneous Breathing Trials will be done at zero PEEP.The use of 5 cm H2O Pressure Support was chosen to allow the patient to demonstrate adequate ventilation without support. It is recognized that the artificial airway imposes some resistance but ET tubes with 7.5 mm ID’s and greater offer minimal imposed work. ET tubes with 6.0 and 7.0 mm ID’s may require 8 and 10 cm H2O PSV respectively to avoid excess imposed work.
The Daily Screening Between 5:30 AM & 8:30 AM all ventilated patients are screened: Weaning Protocol Entry Criteria • PEEP 8 cm H2O • SpO2 90% at FiO2 0.60 • PH 7.35 • The use of sedatives & vasopressors does not specifically contraindicate weaning attempts. • No active ectopy/ischemic changes • Consult with H. O. & RN for clarification • If the patient meets the above criteria, RSBI is preformed. • The RSBI or the reason for deferring the test must be charted daily on all mechanically ventilated patients.
The Daily Screening Between 5:30 AM & 8:30 AM all ventilated patients are screened: When issues arise regarding excess sedation, high dose vasopressors or patients with ongoing cardiac process; consultation between the nurse, physician and respiratory therapist is necessary to determine if attempting weaning is appropriate.All patients must be screened each AM regardless and those meeting the criteria listed will have a RSBI measured. The results or the reason for deferring the RSBI must be charted daily in the medical record.
Rapid Shallow Breathing Index (RSBI) Technique • Ventilator settings for performing a RSBI: • PEEP = 0, PSV = 5, Flow-by at 6/1, FiO2 unchanged • 7.0 mm ET tube, use 8 H2O of PSV • 6.5mm or smaller ET tube, use 10 H2O of PSV • ATC may be used during the RSBI trial instead of a specific PSV level to negate imposed ET tube work. • At the end of 1 minute of unassisted breathing a RSBI is measured. • RSBI results: • RSBI 105 is associated with a 95% likelihood of weaning failure • RSBI < 105 implies an 80% likelihood of successful weaning Yang and Tobin, N Engl J Med 1991; 324: 1445
Using the RSBI to Determine the Next Step • If the RSBI is 105 at the end of one minute, return the patient to their prior ventilator settings. • If the RSBI is < 105; continue on with Spontaneous Breathing Trial (SBT). • Mode - CPAP • PSV - 5 cm H2O • FiO2 - unchanged • PEEP - 0 cm H2O • Trigger Method – Flow-by (6/1)
SBT: Duration and Patient Monitoring • The SBT should be continued for 30 min. to 2 hours if tolerated. • Terminate the SBT if any of the following clinical signs occur: • RR > 35 b/min. for > 5 min. • SpO2 < 90% for > 2 min. • Development of ectopy or ischemic changes • Heart rate > 140 b/min. or 20% from baseline • Systolic BP > 180 mmHg or < 90 mmHg or 20% from baseline • Excessive use of accessory muscles or paradoxical breathing. • Increased anxiety or diaphoresis • Patients unsuccessfully completing a weaning trial will be returned to ventilator settings that achieve acceptable breathing pattern and gas exchange.
SBT: Duration and Patient Monitoring At some point during the SBT, the patient may display signs of agitation, anxiety and tachypnea. In an effort not to prematurely end the weaning trial, the patient must be closely assessed. If this is due to pain or discomfort the patient may require some analgesia or sedation but the SBT should be continued.On the other hand, if the clinical assessment reveals the patient is becoming fatigued (fast rate, low tidal volumes) or the onset of CHF or similar indications of intolerance, the patient should be retuned to the ventilator.The overall goal should be to assure the weaning attempt is continued for as long as possible without endangering the patient.
Physician Notification • If the patient successfully completes a SBT for 2 hours, the managing MD must be paged to decide if extubation is appropriate.
Physician Notification • If the Spontaneous Breathing Trial starts between 5:30 and 6:30 AM, it should be completed by 9:00 AM. While these times are not absolute, they were chosen to allow the physician in rounds an opportunity to assess the patient who was well into their weaning attempt.Literature indicates that approximately 75% of patients that successfully complete a 30 minute to 2 hour SBT can be safely extubated. Contacting the physician to confer on this next step is critical to reducing ventilation days.
Extubation • Within 30 minutes to 2 hours after successful completion of the 2 hour weaning trial, extubation should be considered. The following criteria should be met prior to extubation: • Effective cough with suctioning as well as spontaneous cough • Able to effectively protect airway • Ability to maintain SpO2 90% • RR < 30 b/min
Extubation • There are numerous assessment factors that can be considered to assess safe extubation in addition to those above.A leak around the ET tube (with the cuff deflated) at an airway pressure of 30 cm H2O has been used to determine the presence of tracheal edema.Negative Inspiratory Force measures power – not endurance and carries with it the risk of aspiration as well as discomfort. It is not a reliable predictor of weaning success.The ability to lift the head off of the bed for 5 seconds demonstrates alertness and muscle function and may be the most accurate predictor of the patient’s ability to protect the airway.Testing for gag assesses the reflexes of the upper airway but not necessarily the ability to protect the airway (coughs do that).
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