A coronary artery bypass graft (CABG) is a surgical procedure that helps restore the flow of blood to an obstructed coronary artery. The procedure requires intubation and breathing support from a mechanical ventilator.
Therefore, after the operation, it’s the job of the respiratory therapist to wean the patient off the ventilator so that they can breathe on their own.
In this article, we’ll discuss the steps involved in weaning a CABG patient off the ventilator.
What is a CABG?
A coronary artery bypass graft (CABG) is a surgical procedure performed on patients with coronary artery disease.
Coronary artery disease is caused by the build-up of plaque in the bloodstream, which results in hardened and narrowed arteries over time.
A CABG procedure is performed to provide a new and better path for the blood to travel to the heart rather than through an obstructed coronary artery.
Why is CABG Weaning Important?
A CABG procedure is the most common type of open-heart surgery in the United States, and it generally has a high success rate. However, these post-operative patients are still in critical condition immediately after the procedure.
Therefore, it is the job of the respiratory therapist and medical team to make sure the patient is weaned off the ventilator in a timely manner.
This increases the likelihood of a full recovery and decreases the risk of developing harmful conditions, such as ventilator-associated pneumonia (VAP).
How to Wean a CABG Patient from the Ventilator?
The CABG weaning process is simple as long as you follow the correct protocols. This involves a step-by-step process that is designed to help the patient transition from complete dependence on the ventilator to being able to breathe on their own.
The goal of the weaning process is to help the patient gradually regain their strength and independence.
When the patient first arrives from surgery, the respiratory therapist must evaluate their history and perform a physical assessment. This involves assessing the patient’s respiratory muscle strength, which is one of the most important weaning factors.
CABG Weaning Process
Here are the steps involved in weaning a CABG patient off the ventilator:
A post-operative arterial blood gas (ABG) sample should be collected and analyzed. This allows an assessment of the patient’s oxygenation and ventilation status.
The PaCO2 should be kept within the normal range. Therefore, you must adjust the respiratory rate and tidal volume accordingly to maintain a minute ventilation of 5-12 L/min.
3. Ventilatory Parameters
The respiratory therapist must measure and document the following parameters:
- Respiratory rate
- Tidal volume
- Vital capacity
- Negative inspiratory force
Each parameter provides essential information on the patient’s respiratory muscle strength and, thus, their readiness to wean.
4. Physical Assessment
The respiratory therapist must also check for the following physical attributes:
- Bilateral hand grasps
- Ability to lift their head from the pillow
- Ability to move their extremities
This helps determine the patient’s level of consciousness and physical strength, both of which are important weaning factors.
5. Extubation Criteria
The patient must meet the following criteria before extubation:
- Minute ventilation < 12 L/min
- FiO2 < 60%
- Respiratory Rate < 28 breaths/min NIF > -20 cmH2O
Once the patient is responsive with stable cardiac function and meets these criteria, extubation may be considered. If the criteria have not been met, the patient can be placed on a T-piece to continue weaning.
The decision to extubate will be a collaborative effort between the doctor, respiratory therapist, and nurse.
If the patient requires an FiO2 > 60% or a PEEP > 5 to maintain a PaO2 of 80-100 mmHg and SaO2 > 92%, you should stop the weaning process and notify the physician.
7. Performing Extubation
If all required criteria are met, you may proceed to extubate the patient.
After the tube is removed, the patient can be placed on the FiO2 that they were previously on or whatever concentration it takes to keep their SaO2 and PaO2 within the normal ranges.
8. Monitor the Patient
After extubation, the patient should be closely monitored for any signs of distress, such as an increase in heart rate, respiratory rate, or blood pressure.
If there is a change in the patient’s cardiac or respiratory status, the respiratory therapist should collect an ABG and notify the physician.
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Weaning a CABG patient from the ventilator is a simple process, as long as you follow the correct protocols.
This involves a step-by-step process that is designed to help the patient transition from complete dependence on the ventilator to being able to breathe on their own.
The goal of the weaning process is to help the patient gradually regain their strength and independence. This takes a collaborative effort by the entire healthcare team to ensure the patient’s safety and well-being.
By following the steps outlined above, you can ensure a smooth and successful weaning process for your CABG patients. To learn more, check out our complete guide on ventilator weaning. Thanks for reading!
John Landry, BS, RRT
John Landry is a registered respiratory therapist from Memphis, TN, and has a bachelor's degree in kinesiology. He enjoys using evidence-based research to help others breathe easier and live a healthier life.
- Faarc, Kacmarek Robert PhD Rrt, et al. Egan’s Fundamentals of Respiratory Care. 12th ed., Mosby, 2020.
- Chang, David. Clinical Application of Mechanical Ventilation. 4th ed., Cengage Learning, 2013.
- Rrt, Cairo J. PhD. Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications. 7th ed., Mosby, 2019.
- “Automated Weaning from Mechanical Ventilation after Off-Pump Coronary Artery Bypass Grafting.” PubMed Central (PMC), 2017, www.ncbi.nlm.nih.gov/pmc/articles/PMC5359227.
- “Course of Weaning from Prolonged Mechanical Ventilation after Cardiac Surgery.” National Center for Biotechnology Information, U.S. National Library of Medicine, 2006, www.ncbi.nlm.nih.gov/pmc/articles/PMC1524720https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1524720/.