# Magnitude of Pulse Pressure Variation is Associated with Qp:Qs Imbalance during Pediatric Cardiac Surgery: A Two-Center Retrospective Study

## TL;DR

This study found that pulse pressure variation is linked to blood flow imbalance in children undergoing heart surgery, suggesting clinicians should consider this when evaluating patients.

## Contribution

The study demonstrates that PPV is associated with Qp:Qs imbalance in pediatric cardiac surgery patients, offering new clinical insights.

## Key findings

- Baseline PPV varied significantly by congenital heart disease type, with atrial septal defect having the lowest PPV.
- The high Qp:Qs group had significantly lower PPV compared to the low Qp:Qs group.
- PPV decreased significantly after systemic-pulmonary shunt procedures.

## Abstract

Pulse pressure variation (PPV) is based on heart-lung
interaction and its association with the imbalance between pulmonary and systemic
blood flow (Qp:Qs) has been understudied. We hypothesized that (1) baseline PPV
(after induction of anesthesia) is different in a mixed congenital heart disease
population with different Qp:Qs, (2) baseline PPV is different between a pooled
group with high Qp:Qs and one with low Qp:Qs, and (3) a systemic-pulmonary shunt
procedure results in reduced PPV compared to baseline.

We
retrospectively reviewed the medical charts of children who presented to the
operating room for cardiac surgery between 2010 and 2018. General patient
characteristics, PPV, and other hemodynamic parameters following the induction of
general anesthesia were retrieved. Patients were grouped according to the type of
congenital heart disease, and whether the Qp:Qs ratio was higher or lower than 1.
We also identified patients who received a systemic-pulmonary shunt in order to
evaluate changes in PPV.

A total of 1253 patients were included
in the study. Baseline PPV differed significantly according to the type of
congenital heart disease, with atrial septal defect showing the lowest PPV (9.5
± 5.6%) and tricuspid valve malformation the highest (21.8 ±
14.1%). The high Qp:Qs group (n = 932) had significantly lower PPV compared to
the low Qp:Qs group (n = 321; 11.8 ± 5.7% vs. 14.9 ± 7.9%,
respectively; p
< 0.001). PPV decreased significantly following
systemic-pulmonary shunt.

PPV was associated with Qp:Qs
imbalance in children undergoing general anesthesia for cardiac surgery. A lower
PPV was associated with increased Qp:Qs. Clinicians should take this into account
when using PPV to evaluate volume status and when conducting clinical trials in a
mixed population of patients with congenital heart disease.