# Mechanical ventilation protocol

 Mechanical ventilation Microchapters

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Vishnu Vardhan Serla M.B.B.S. [2]

## Overview

Candidacy for mechanical ventilation is based on specific criteria and clinical condition of the patient. Body weight of the patient and height also play important role in determining the optimal ventilator settings. Similar to initiation of mechanical ventilation there are specific criteria for weaning the patient off from the ventilator and doing a spontaneous breathing trial.

## Protocol

### Inclusion Criteria

• PaO2 <= 300 ( corrected for altitude)
• Bilateral (patchy, diffuse or homogenous) infiltrates consistent with pulmonary edema
• No clinical evidence of left atrial hypertension

### Ventilator Setup

• Calculate predicted body weight. It is calculated using the formula
Males = 50 + 2.3[height(in inches)-60]
Females = 45.5 + 2.3[height(in inches)-60]
• Selecting the ventilator mode
• Set ventilator settings to achieve initial Vt = 8 ml/kg of predicted body weight
• Reduce VT by 1 ml/kg at intervals ≤ 2 hours until VT = 6ml/kg.
• Set initial rate to approximate baseline minute ventilation (not > 35 breaths per minute).
• Adjust VT and respiratory rate to achieve pH and plateau pressure goals below.

#### Oxygenation Goal

• PaO2 55-80 mmHg or SpO2 88-95% is the goal.
• Use a minimum PEEP of 5 cm H2O.
• Consider use of incremental FiO2/PEEP combinations to achieve goal.
Lower PEEP/Higher FiO2
 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 18-24
Higher PEEP/Lower FiO2
 FiO2 0.3 0.3 0.3 0.3 0.3 0.4 0.4 0.5 0.5 0.5 - 0.8 0.8 0.9 1 1 PEEP 5 8 10 12 14 14 16 16 18 20 22 22 22 24

#### Plateau Pressure Goal

• Plateau pressure goal(Pplat) is <= 30 cm H2O
• Check Pplat every 4th hourly after change in PEEP ot VT
• If Pplat > 30 cm of H2O
Decrease VT by 1ml/kg
• If Pplat < 25 cm of H2O and VT < 6ml/kg
Increase VT by 1ml/kg unbtil Pplat > 25 cm H2O or VT = 6 ml/kg
• If Pplat < 30 cm and breath stacking or dys-synchrony occurs
Increase VT in 1 ml/kg increments to 7 or 8 ml/kg, if Pplat remains <=30 cm of H2O

#### PH Goal

• pH should be maintained at 7.30 - 7.45
• If pH is less than 7.30 (acidosis)

a. Range of 7.15 - 7.30

Increase respiratory rate until pH > 7.30
Maximum rate can be 35 breaths/min

b. Less than 7.15

Increase respiratory rate to 35
VT can be increased in 1 ml/kg until pH >7.15 (Pplat target of 30 may be exceeded)
Bicarbonate can be given
Decrease the ventilation rate if possible

#### I:E Ratio Goal

Recommend that duration of inspiration be less than equal to duration of expiration.

### Weaning

A spontaneous breathing trial has to be done daily when

• FiO2 ≤ 0.40 and PEEP ≤ 8.
• PEEP and FiO2 ≤ values of previous day.
• Patient has acceptable spontaneous breathing efforts. (May decrease vent rate by 50% for 5 minutes to detect effort.)
• Systolic BP ≥ 90 mm Hg without vasopressor support.
• No neuromuscular blocking agents or blockade.

Spontaneous Breathing Trial

If all above criteria are met and patient has been in the observed for at least 12 hours, initiate a trial of upto 120 minutes of spontaneous breathing with FiO2 < 0.5 and PEEP < 5

1. Place on T-piece, trach collar, or CPAP ≤ 5 cm H2O with PS < 5

2. Assess for tolerance as below for up to two hours.

a. SpO2 ≥ 90: and/or PaO2 ≥ 60 mm Hg b. Spontaneous VT ≥ 4 ml/kg predicted body weight c. RR ≤ 35/min d. pH ≥ 7.3 e. No respiratory distress (distress= 2 or more)

HR > 120% of baseline
Marked accessory muscle use
Diaphoresis
Marked dyspnea

3. If tolerated for at least 30 minutes, consider extubation.

4. If not tolerated resume pre-weaning settings.

## References

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2. Grebennikov VA, Kriakvina OA, Bolunova ES, Degtiareva MV (2013). "[Prognostic criteria of the premature infants weaning from mechanical ventilation during trigger ventilation]". Anesteziol Reanimatol (in Russian) (1): 26–30. PMID 23808249.
3. Valenzuela J, Araneda P, Cruces P (March 2014). "Weaning from mechanical ventilation in paediatrics. State of the art". Arch. Bronconeumol. 50 (3): 105–12. doi:10.1016/j.arbres.2013.02.003. PMID 23542044.
4. Al Ashry HS, Modrykamien AM (2014). "Humidification during mechanical ventilation in the adult patient". Biomed Res Int. 2014: 715434. doi:10.1155/2014/715434. PMC 4096064. PMID 25089275.
5. Wielenga JM, van den Hoogen A, van Zanten HA, Helder O, Bol B, Blackwood B (March 2016). "Protocolized versus non-protocolized weaning for reducing the duration of invasive mechanical ventilation in newborn infants". Cochrane Database Syst Rev. 3: CD011106. doi:10.1002/14651858.CD011106.pub2. PMID 26998745.
6. Toft P, Olsen HT, Jørgensen HK, Strøm T, Nibro HL, Oxlund J, Wian KA, Ytrebø LM, Kroken BA, Chew M (December 2014). "Non-sedation versus sedation with a daily wake-up trial in critically ill patients receiving mechanical ventilation (NONSEDA Trial): study protocol for a randomised controlled trial". Trials. 15: 499. doi:10.1186/1745-6215-15-499. PMC 4307177. PMID 25528350.