Irtaza rasheed care33, Slides of Computer science

Download Irtaza rasheed care33 and more Slides Computer science in PDF only on Docsity!

Basics of

Cardiopulmonary

Anatomy

Relevant to ECMO

Presented by: Asra Khan

Heart

• (^) The heart is hollow, conical muscular organ.
• (^) Acts as a pump, beats approximately 2.5 billion times in a lifetime.
• (^) It is about 12cm long, 9cm wide and 6cm thick with an average mass of 250g in adult females and 300g in males.
• (^) It rests on diaphragm, near the midline of the thoracic cavity.
• (^) It lies in “mediastinum” an anatomical region that extends from sternum to vertebral column, from 1 st rib to diaphragm and between the lungs.

Relations of the heart:

• (^) Superiorly: Aorta, SVC, pulmonary artery and pulmonary vein.
• (^) Inferiorly: Diaphragm.
• (^) Posteriorly: Esophagus, trachea, left and right bronchus, descending aorta, IVC, thoracic vertebrae.
• (^) Anteriorly: Ribs and intercostal muscles.
• (^) Laterally: Lungs.
• (^) Apex is formed by the tip of left ventricle and rests on diaphragm.
• (^) Base of the heart is its posterior surface, and formed by atria of the heart.

Right atrium (RA):

• (^) RA forms right border of heart receives blood from SVC,IVC and coronary sinus.
• (^) It is about 2-3 mm in diameter.
• (^) Posterior wall is smooth but anterior wall is rough due to presence of muscular ridges called pectinate muscles.
• (^) RA and LA separated by inter-atrial septum, prominent feature of which is an oval depression called Fossa Ovalis.
• (^) Between RA and RV there is tricuspid valve having three leaflets anterior, septal and inferior. The cusps are attached tendon like cords called “chordae tendineae”, which in turn are connected to cone shaped “papillary muscles”.

ECMO Relevance:

• (^) RA is common site for venous drainage cannula. (VA, VV ECMO)
• (^) Dual-lumen VV- cannulas (e.g., internal jugular) sit with ports in SVC/IVC and RA.
• (^) Adequate venous return is critical for ECMO.

ECMO Relevance:

RV failure may occur in:

• (^) Pulmonary hypertension.
• (^) Massive Pulmonary Embolism.
• (^) Severe ARDS.
• (^) VA ECMO reduces RV workload by bypassing pulmonary circulation.
• (^) VV ECMO improves oxygenation and may reduce pulmonary vasoconstriction.

Left Atrium (LA):

• (^) It is about same thickness as about right atrium and form most of the base of heart.
• (^) It has smooth anterior and posterior walls, because pectinate muscles are confined to the auricle of left atrium.
• (^) From LA blood enters LV through bicuspid valve having 2 cusps anterior and posterior.

Left Ventricle (LV):

• (^) Thickest chamber of heart about 10-15mm and forms the apex of heart.
• (^) Like RV, the LV also have trabeculae carnaea and has chordae tendineae that anchors the cusps of bicuspid valves to papillary muscles.
• (^) Blood passes from LV through aortic valve having 3 cusps left and right coronary cusp and non coronary cusp, into ascending aorta from here blood enters into coronary arteries, branching from ascending aorta and carry blood to heart wall.
• (^) Reminder of blood passes into arch of aorta and descending aorta, which further passes blood throughout the body

ECMO Relevance:

• (^) LV dysfunction leads to cardiogenic shock, which is ultimately an indication for VA-ECMO.
• (^) May require LV venting strategies.

ECMO Cannulation Sites:

• (^) Femoral vein.
• (^) Internal jugular vein.
• (^) Femoral artery.
• (^) Central cannulation (right atrium & ascending aorta in post-cardiotomy patients).

Lung Anatomy & Circulation

• (^) Respiratory system uses oxygen continuously for metabolic reactions that release energy from nutrient molecules and help in ATP production, in the meantime, carbon dioxide is also released.
• (^) This system also helps in maintenance of homeostasis by providing the facility of gaseous exchange between air, blood and tissue cells.

ECMO Relevance:

• (^) VV ECMO is used when alveolar gas exchange fails (e.g., severe ARDS).
• (^) ECMO allows lung-protective ventilation:
  • (^) Low tidal volumes.
  • (^) Lower plateau pressures.
  • (^) Reduced FiO₂.
• (^) Goal: Minimize ventilator-induced lung injury (VILI).

Alveoli:

• (^) Structure:
• (^) ~300 million alveoli
• (^) Extremely thin alveolar-capillary membrane (~0.5 microns).
• (^) Huge surface area (~70 m²). Cellular Components:
• (^) Type I pneumocytes:
  • (^) Thin.
  • (^) Primary site of gas diffusion.
• (^) Type II pneumocytes:
  • (^) Produce surfactant.
  • (^) Prevent alveolar collapse.
• (^) Pulmonary capillaries:
  • (^) Dense network surrounding alveoli.