Revised 12-06-07
SICU VENTILATOR WEANING PROTOCOL
Purpose: To facilitate a respiratory therapist-initiated ventilator weaning procedure in order to
minimize the duration of mechanical ventilation. The following protocol is to be construed as a
clinical guideline only. It is not intended to establish policy or a medical standard of care for
discontinuation of mechanical ventilation nor is it intended to replace the medical judgment of the
treating physician.
1. Daily Assessment of Readiness to Wean from Ventilator: Every morning, each patient
should be assessed by the Respiratory Therapist (RT) and RN for the following criteria to
determine whether or not they are ready for a Spontaneous Breathing Trial (SBT):
a. Resolution or stabilization of the underlying disease process that contributed to the
need for mechanical ventilation
b. Not receiving continuous sedation or neuromuscular blocking drugs and no residual
effects from prior neuromuscular blockade
c. Exhibiting spontaneous respiratory efforts
d. Cough/gag present or patient has tracheostomy
e. Intracranial pressure </= 20 cm H2O and not requiring frequent interventions to be
controlled
f. No signs or symptoms of hemodynamic instability, unstable dysrhythmia, or
myocardial ischemia
g. FiO2 </= 0.50, PEEP </= 5 cm H2O, SaO2 >/= 90%, PaO2:FiO2 ratio >200
h. Minute ventilation </= 12-15 L/min
i. Serum pH 7.3 to 7.5
j. A request to avoid weaning has not been made by a physician.
If all of the criteria are not met, then the patient should continue on their current ventilator
settings and be reassessed the next morning.
2. Calculation of Rapid Shallow Breathing Index (RSBI): If a patient meets the above
criteria, the RT should ask the patient’s physician if it would be appropriate to proceed with
a “weaning trial”. If the answer is “yes”, then a type-in order should be entered in TDS
under the respiratory section that states, “Initiate ventilator weaning protocol now.” If the
order is initiated by the physician, they should contact the RT on duty to let them know that
a “weaning protocol” order has been entered in the computer. Once the order is entered, it
will be noted on the bedside ventilator flowsheet by the RT and will remain in effect until
either the patient is extubated or a physician cancels it.
Once the order has been entered in the computer, a RSBI should be calculated by
placing the patient on CPAP of 5 cm H2O with Pressure Support (PS) = 5 cm H2O. After
one minute, the spontaneous respiratory rate and tidal volume are measured and the RSBI
is calculated (RSBI = f/Vt). If the RSBI is > 105 (80 for elderly/debilitated patients), then
the patient should return to their previous, non-fatiguing ventilator settings and be
reassessed 6-8 hours later (not more than 2 times/day). If the RSBI is < 105 (80 for
elderly/debilitated patients), then a SBT should commence. The results of the RSBI should
be recorded each morning on the top of the ventilator flow sheet at the patient’s bedside.
3. Spontaneous Breathing Trial (SBT): A SBT consists of a 30-90 minute trial of
spontaneous breathing with CPAP = 5 cm H2O, PS = 5 cm H2O, and FiO2 = to current
settings (</= 0.5) (Note: prior to initiating a SBT, the RT and RN should review a patient’s
physiologic status and planned treatments to determine if the patient is appropriate for a
SBT). If the patient meets any of the following criteria, the trial should be terminated and
the patient returned to their previous, non-fatiguing ventilator settings and a SBT can be
repeated 6-8 hours later (not to more than 2 times/day):
a. Respiratory rate > 30 for 5 minutes or more
b. SaO2/SpO2 < 90% for 30 seconds or more
c. Heart rate > 140 bpm or sustained increase or decrease of 20% from baseline
d. New onset hypertension (SBP >180 mmHg) or hypotension (SBP <90 mmHg)
e. Sustained increase in anxiety, diaphoresis, or other signs of respiratory distress
f. Cardiac instability or dysrhythmia
g. pH </= 7.32
h. ICP > 20 cm H2O
i. RSBI > 105 (80 for elderly/debilitated patients)
If the patient successfully completes the SBT, they should be considered for extubation
(see #4).
4. Assessment of Readiness for Extubation: If the patient successfully completes a SBT,
then the following criteria should be assessed to determine readiness for extubation:
a. Does not require suctioning more than every 2 hours
b. Anticipated adequate spontaneous cough and ability to protect airway
c. Endotracheal tube cuff leak AUDIBLE when cuff deflated (after suctioning
oropharynx) and patient either spontaneously breathing on Pressure Support 0-10
cm H2O or receiving a set tidal volume </= 10 cc/kg. If cuff leak not present,
consult attending of primary service for permission to either initiate a 24-hour
course of Decadron (10 mg IV q 6 hours), consult ENT service for direct
laryngoscopy, or extubate patient in the presence of Anesthesia due to a potentially
difficult airway.
d. No known history of upper airway obstruction, edema, or stridor within previous 48
hours.
e. Negative Inspiratory Force (NIF) < -20 cm H2O (if patient is following commands)
f. Spontaneous tidal volume >5 cc/kg
g. Vital Capacity > 10 cc/kg
h. Minute Ventilation < 12 L/min
i. Stomach is empty and not distended
If these criteria are met, the SICU resident (pager 506-5503) should be contacted for a
potential order for extubation. If the patient is not extubated, then they should return to
their previous, non-fatiguing ventilator settings and be reassessed 6-8 hours later. The
results of the SBT and the weaning parameters should be entered at the top of the bedside
ventilator flowsheet.