INITIAL VENTILATOR TIDAL VOLUME AND RATE ADJUSTMENTS

**Calculate predicted body weight (PBW)**- Male= 50 + 2.3 [height (inches) - 60] or 50 + 0.91 [height (cm) - 152.4]
- Female= 45.5 + 2.3 [height (inches) - 60] or 45.5 + 0.91 [height (cm) - 152.4]

- Mode: Volume Assist-Control
- Set initial tidal volume to 8 ml/kg PBW
- Reduce tidal volume to 7 ml/kg after 1-2 hours and then to 6 ml/kg PBW after 1-2 hours
- Set initial ventilator rate to maintain baseline minute ventilation (not > 35 bpm)

SUBSEQUENT TIDAL VOLUME ADJUSTMENTS

Plateau Pressure Goal: ≤ 30 cmH_{2}O

Check inspiratory plateau pressure (Pplat) with 0.5 second inspiratory pause at least every four hours and after each change in PEEP or tidal volume.

- If Pplat > 30 cmH
_{2}O, decrease tidal volume by 1 ml/kg PBW steps to 5 or if necessary to 4 ml/kg PBW. - If Pplat < 25 cmH
_{2}O and tidal volume < 6 ml/kg, increase tidal volume by 1 ml/kg PBW until Pplat > 25 cmH_{2}O or tidal volume = 6 ml/kg. - If breath stacking or
severe dyspnea occurs, tidal volume may be increased (not
required) to 7 or 8 ml/kg PBW if Pplat remains ≤
30 cmH
_{2}O.

ARTERIAL OXYGENATION

GOAL: PaO_{2} 55-80 mm Hg or SpO_{2} 88-95%

Use these FiO_{2}/PEEP combinations to achieve oxygenation goal.

FiO2 | 0.3 | 0.4 | 0.4 | 0.5 | 0.5 | 0.6 | 0.7 | 0.7 | 0.7 | 0.8 | 0.9 | 0.9 | 0.9 | 1.0 |

PEEP | 5 | 5 | 8 | 8 | 10 | 10 | 10 | 12 | 14 | 14 | 14 | 16 | 18 | 20-24 |

RESPIRATORY RATE (RR)
AND ARTERIAL pH

ARTERIAL pH GOAL: 7.30-7.45

- Acidosis Management:
- If pH 7.15-7.30:
- Increase set RR until pH > 7.30 or PaCO
_{2}< 25 (Maximum Set RR =35) - If set RR = 35 and pH < 7.30, NaHCO
_{3}may be given (not required)

- Increase set RR until pH > 7.30 or PaCO
- If pH < 7.15:
- Increase set RR to 35.
- If set RR = 35 and
pH < 7.15 and NaHCO
_{3}has been considered, tidal volume may be increased in 1 ml/kg PBW steps until pH > 7.15 (Pplat target may be exceeded).

- If pH 7.15-7.30:
- Alkalosis Management: (pH > 7.45):
- Decrease set RR until patient RR > set RR.

Minimum set RR = 6/min.

- Decrease set RR until patient RR > set RR.
- I:E RATIO

GOAL: 1:1.0 - 1:3.0- Adjust flow rate and inspiratory flow wave-form to achieve goal.

- WEANING:
- Conduct A CPAP trial daily when:
- FiO
_{2}≤ 0.40 and PEEP ≤ 8, and - PEEP and FiO
_{2}≤ values of previous day, and - Patient has spontaneous breathing efforts (may decrease vent set rate by 50% for 5 minutes to detect effort), and
- Systolic BP ≥ 90 mm Hg without vasopressor support.

- Set: CPAP = 5 cmH
_{2}O, FiO_{2}= 0.50. - If patient RR ≤ 35 for 5 min., advance to Pressure Support Weaning (See below)
- If patient RR > 35, return to previous A/C settings and reassess for weaning next morning.

- FiO
- Pressure Support (PS) Weaning Procedure
- Set PEEP = 5 and FiO
_{2}= 0.50 - Set initial PS based on RR during CPAP trial:
- If CPAP RR < 25: set PS = 5 cmH
_{2}O and go to REDUCING PS steps 3.3 to 3.4 - If CPAP RR = 25-35: set PS = 20 cmH
_{2}O, then reduce by 5 cmH_{2}O at ≤ 5 min. intervals until patient RR = 26-35, then go to REDUCING PS step 3.1 - If initial PS not tolerated: return to previous A/C settings.

- If CPAP RR < 25: set PS = 5 cmH

- Set PEEP = 5 and FiO
- REDUCING PS: (No reductions made after 1700 hrs)
- Reduce PS by 5 cmH
_{2}O q 1-3 hr. - If PS ≥ 10 cmH
_{2}O not tolerated, return to previous A/C settings (If Weaning Tolerance Criteria O.K., resume last tolerated PS level next morning and go to step 3.1). - If PS = 5 cmH
_{2}O not tolerated, go to PS = 10 cmH_{2}O. If tolerated, PS of 5 or 10 cmH_{2}O may be used overnight with further attempts at weaning the next morning. - If PS = 5 cmH
_{2}O tolerated for ≥ 2 hours, assess for ability to sustain unassisted breathing (See below).

- Reduce PS by 5 cmH
- UNASSISTED BREATHING TRIAL
- Place on T-piece, trach collar, or CPAP < 5 cmH
_{2}O - Assess for tolerance as below for two hours.
- If tolerated, consider extubation.
- If not tolerated, resume PS 5 cmH
_{2}O.

- Place on T-piece, trach collar, or CPAP < 5 cmH

- Conduct A CPAP trial daily when:

Definition of Weaning Intolerance

- RR > 35 (may exceed 35 ≥ 5 minutes), and
- SpO
_{2}< 88% (< 5 minutes at < 88% may be tolerated), and - Respiratory distress (≥ 2 of the following):
- Pulse > 120% of rate at 6 A.M. > 5 minutes
- Marked use of accessory muscles
- Abdominal paradox
- Diaphoresis
- Marked complaint of dyspnea

Definition of Unassisted Breathing Intolerance

- RR > 35
- SpO
_{2}< 90 % and/or PaO_{2}< 60 mm Hg, and - Spontaneous tidal volume < 4 ml/kg PBW, and
- Respiratory distress (any two of the following):
- Pulse > 120% of usual rate for > 5 minutes
- Marked use of accessory muscles
- Abdominal paradox
- Diaphoresis
- Marked complaints of dyspnea