Mechanical Ventilation Management And Congenital Cardiac Surgery

Dr. Kamal K. Pourmoghadam

Altered resp. mechanics & positive press ventilation have significant influence on hemodynamic

Approach to ventilation should not be focused to achieve desired gas exchange, rather it should be influenced by cardiorespiratory interactions

Endotracheal Tube
Narrowest segment of airway, prior to puberty is below the cords, at level of cricoid cartilage
Generally uncuffed tubes have been recommended

If expecting a significant leak, or airway edema
Change ETT to a Larger size, or cuffed ETT
Cuffed ETT at the time of initial intubation and leave the cuff deflated

Endotracheal Tube
Nasal approach
ETT easier to secure,
Less likely to move in trachea
Less irritation, inflammation, and less likely to lead to stenosis
Comfortable, with less gagging

Cardiorespiratory interactions
Vary significantly between patients
Is not possible to provide specific ventilatory strategies for all patients
Mode of ventilation should be adjusted to each patient’s hemodynamic status to achieve adequate CO, and gas exchange
Thus frequent modifications to mode and pattern of ventilation maybe necessary during the recovery period
With attention to lung volume and airway pressure

Changes in lung volume have significant impact on PVR
PVR is lowest at FRC
Hypo, or hyperinflation may result in significant increase in PVR
Due to altered traction on alveolar septae and extra-alveolar vessels
Positive pressure ventilation influences preload and afterload on the heart

Afterload on pulmonary ventricle is increased during positive press. Breath
Due to changes in lung volume, and increase in mean intrathoracic press.
If this is significant or limited reserve
RV stroke vol. maybe reduced, and RVEDP maybe increased
Can lead to low CO state and signs of RV dysfunction
•Tricuspid regurgitation, hepatomegally, ascites, and pleural effusions

Afterload on the systemic ventricle is decreased during a positive press. breath, in contrast to RV
Due to a fall in ventricle transmural pressure
Thus patients with LV dysfunction and increased LVEDV/LVEDP
Can have impaired pulmonary mechanics
•Secondary to increased lung water, decreased lung compliance, and increased airway resistance
•Leading to increased work of breathing in neonates and infants resulting in poor feeding and failure to thrive
•Thus positive press ventilation can reduce the work of breathing and O2 demand in patients with LV dysfunction, and volume overload
During weaning, CPAP or press support maybe helpful in these patients

PEEP utilization has been controversial in congenital heart patients
Initially perceived not to have a positive impact on gas exchange, and be detrimental to hemodynamic, and lead to lung injury
However, PEEP increases FRC leading to lung recruitment, and redistributes lung water from alveolar septae to more compliant perihilar regions
These lead to improved gas exchange, and decreased PVR
PEEP should be used in all mechanically ventilated patients after congenital heart surgery
Excessive levels can be detrimental by increasing afterload on RV
3-5 cmH2O of PEEP will help maintain FRC, and redistribute lung water without negative impact on hemodynamic

Conclusion
Mode of ventilation should be adjusted to each patient’s hemodynamic status to achieve adequate CO, and gas exchange
Cardiorespiratory mechanics should be optimized throughout the perioperative period which includes prior to the operation, intraoperative, during transport, and in the Intensive Care Unit Kamal K. Pourmoghadam, MD, is a pediatric cardiac surgeon at The Heart Center at Arnold Palmer Hospital for Children. He is board certified in general surgery, cardiothoracic surgery and congenital cardiac surgery.

About Dr. Kamal K. Pourmoghadam

Kamal Pourmoghadam, MD, is a pediatric cardiac surgeon at The Heart Center at Arnold Palmer Hospital for Children. He is board certified in general surgery, cardiothoracic surgery and congenital cardiac surgery.

Dr. Pourmoghadam earned his bachelor’s degree from University of California, Berkeley, and his medical degree from Albany Medical College in New York. He trained for adult cardiac surgery at the University of Miami, Jackson Memorial Hospital in Miami, and for congenital cardiac surgery at the University of Washington, Seattle Children’s Hospital in Seattle.

Dr. Pourmoghadam is a professor of surgery at the University of Central Florida College of Medicine, practicing congenital cardiac surgery for over twenty years and has been active in clinical research. He has extensive experience in neonatal and infant cardiac surgery and has special interest in the repair of single ventricle physiology patients and research in univentricular hearts.
References:

Website: https://kamalpourmoghadam.com
Blog: https://drpourmoghadam.home.blog/
News: https://hippocratesguild.com/dr-kamal-pourmoghadam
News: https://medicogazette.com/dr-kamal-pourmoghadam#425f92ce-0ccc-4fe2-8c31-56cf497704f4
News: https://hype.news/dr-kamal-pourmoghadam/
News report about Dr. Pourmoghadam: http://www.tiogapublishing.com/features/the_marketplace/covington-tot-returns-home-to-pennsylvania-after-lengthy-oklahoma-hospital/article_04865c00-0ae5-11e1-aec8-001cc4c002e0.html
Linkedin: https://www.linkedin.com/in/kamal-pourmoghadam-9a796157/

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