Prolonged mechanical ventilation can have serious adverse effects on a patient’s health, such as ventilator-associated pneumonia. Therefore, it is crucial to wean patients off the ventilator as soon as possible.

Mechanical Ventilator Weaning

Mechanical ventilator weaning is the process of gradually reducing the ventilator support until the patient can breathe on their own. The goal of weaning is to decrease the patient’s dependence on the ventilator, reduce the risk of complications, and improve their overall respiratory function. Weaning can be challenging, as it requires a delicate balance between providing adequate support and avoiding the risks of prolonged mechanical ventilation.

Criteria for Weaning

Some necessary indications that indicate the possibility of separating the patient from the ventilator

  • Criteria Related to the Patient
    1. Spontaneous Breath
    2. Conscious
    3. Intact Cough Reflex
    4. Intact Gag Reflex
  • Criteria Related to the ECG
    • Normal Electrocardiogram
  • Criteria Related to the Vital Signs
    1. Normal Temperature
    2. Normal Heart Rate
    3. Normal BP
    4. No Pain
  • Criteria Related to the ABG
    1. pH is Normal
    2. PaCo2 Less than 50%
    3. SaO2 More than 90%
    4. FiO2 Less than 40:50%
  • Criteria Related to the Mechanical Ventilator
    1. PEEP Less than Normal Range
    2. PaO2 More than 100% in Presence of PEEP
    3. PaO2 More than 60% in Absence of PEEP
    4. FiO2  Less than 40%

Weaning Stages

The weaning process typically involves four stages:

  • First Stage :  Preparation

During this stage, the medical team assesses the patient’s readiness for weaning and prepares a weaning plan. This plan may include measures to improve the patient’s respiratory function, such as physical therapy, nutritional support, and bronchodilator therapy.

  • Second Stage : Reduction

This stage involves gradually reducing the ventilator support, such as by decreasing the level of positive end-expiratory pressure (PEEP) or the fraction of inspired oxygen (Fio2). The mechanical ventilator modes used in weaning include SIMV, CPAP, BIPAP, or PSV.

  • Third Stage : Trial

The trial stage involves temporarily disconnecting the patients from the ventilator to see if they can breathe on their own. This trial may involve a spontaneous breathing trial (SBT), which assesses the patient’s ability to breathe without ventilator support for a specified period. During the SBT, the patient’s respiratory rate, oxygen saturation, and other vital signs are closely monitored. If the patient is successful in the trial, they move on to the liberation stage. The practical procedure for the weaning include:

  1. Suction the patient airway.
  2. Installing the T-Tube, which is a connection in a T-shape, has openings on both sides and in the middle. Its benefit is that, through that the patient can have nebulizer sessions while he is connected to the ventilator. It also helps in the process of weaning the patient from the device, because the patient may have to reconnect to the device because he is unable to breath by himself, and this process can put the patient into respiratory or cardiac arrest. So the patient is connected to this connection with 100% oxygen so that he can get used to take  on his own breath.
  3. Medications: 2 ampoules of magnesium sulfate on 100 saline solutions and an ampoule of solucortef.
  4. Nubilizer sessions, whether Atrovent or Palmacort or Varcoline.
  5. Do an ABG after half an hour, and if the results are normal, the patient will be weaned; if they are not normal, the patient will go back to the mechanical ventilator.
  • Fourth Stage : Liberation

The liberation stage involves complete discontinuation of mechanical ventilation, and the patients is now breathing on their own. However, it is essential to continue monitoring the patient’s respiratory function and providing supportive care, such as oxygen therapy or non-invasive positive pressure ventilation, to avoid reintubation. In this stage, the patient may be intolerance to the weaning.

Patient Intolerance

There are some signs that indicate the patient intolerance to the weaning from mechanical ventilator and must be reintubation for reconnection, these signs include:

  • Criteria Related to the Patient
    1. Dyspnea
    2. Fatigue Inspiratory
    3. Low Level of Consciousness
    4. Anxiety
    5. Diaphoresis
  • Criteria Related to the ECG
    • Dysrhythmia
  • Criteria Related to the Vital Signs
    • Abnormal Vital Signs
  • Criteria Related to the Mechanical Ventilator
    1. PEEP More than Normal Range
    2. PaO2 Less than 100% in Presence of PEEP
    3. PaO2 Less than 60% in Absence of PEEP  
  • Criteria Related to the ABG
    1. pH Less than 7,25  
    2. PaO2 Less than 50%
    3. SaO2 Less than 90%
    4. PaCO2 More than 50%

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