【Pediatric Anesthesia】Cardiac catheterization evaluation for congenital heart disease

When clinical information is unclear or conflicting, cardiac catheterization is required to clarify anatomy and physiology, or to clarify coronary or aortopulmonary collateral anatomy

Shunt localization is usually determined from angiography combined with oxygen saturation measurements of the pulmonary veins, superior and inferior vena cava, right and left ventricles, aorta, and pulmonary arteries

The shunt flow was quantified according to the ratio of body and pulmonary blood flow

Qp=VO2/(PvO2-PaO2)

PaO2 is the oxygen content in the pulmonary artery, PvO2 is the oxygen content in the pulmonary vein, and VO2 is the oxygen consumption

Qs=VO2/(SaO2 -MvO2)

SaO2 is the systemic arterial blood oxygen content, and MvO2 is the mixed venous blood oxygen content

After calculating Qp and Qs, the shunting can be quantified

Qp/Qs=(Sa02-Mv02)/(PvO2-PaO2)

Furthermore, if the FO2 is low at the time of blood sampling, the dissolved oxygen fraction (P02 x 0.
003) can be neglected
.

About removing the hemoglobin × 1.
34 term, the equation can be further simplified to four oxygen saturations
.

Qp/Qs=(SaO2-MvO2)/(PvO2-PaO2)

A Qp/Qs>2.
0 indicates a larger shunt, and a Qp/Qs of 1.
25-1.
5 indicates a smaller shunt
.

Qp/Qs<1.
0 indicates that the shunt is a net RL shunt
.

Effective pulmonary blood flow (Qpeff) and effective systemic blood flow (Qseff) must be calculated when bidirectional shunts are present
.

Qpeff is the volume of systemic venous blood flowing through the pulmonary capillaries for oxygenation
.

Qseff refers to pulmonary venous blood flow through systemic capillaries to supply oxygen to tissues
.

Qpeff and Qseff are always equal
.

Qseff=Qpeff=VO2(PvO2-MvO2)

LR split is defined as Qp-Qpeff and RL split is defined as Qs-Qpeff Net split is the difference between the two
.

In the presence of LR shunts and elevated PVR, repeated measurements of pressure and saturation are usually performed while the patient is inhaling pure oxygen to assess the effects of pulmonary vascular bed responsiveness and ventilation/perfusion abnormalities on hypoxemia
.

If inhalation of pure oxygen or NO increases pulmonary blood flow and Qp/Qs increases significantly as PVR decreases, it suggests a reversible process, such as pulmonary vascular hypoxic constriction leading to increased PVR
.

The patient's high PVR does not respond to pure oxygen or NO, and although the shunt hole is large, the LR shunt is small, suggesting that the patient may have irreversible obstructive pulmonary vascular disease causing extensive pulmonary vascular damage
.

Angiography during cardiac catheterization can reveal anatomical abnormalities
.

Special projection angles provide specific information on defect location and extent
.

Ventricular function is assessed by angiography and physiology (eg, manometry)
.

Calculated ventricular size is of great importance in assessing circulatory support in children with ventricular hypoplasia
.

Article from: Gregory's Pediatric Anesthesia

Notes / Wu Yajun

Typography/Ding dang balls hemp