What is the clinical evidence from this study?

Study design: Observational. Population: Normal dogs (n=12). Intervention: Inspiration vs. Expiration. Primary outcome: Peak velocity and velocity-time integral of pulmonary venous flow.

January 1, 1999Open Access

Effects of Respiratory Cycle on Pulmonary Venous Flow and Cardiac Cycle on Pulmonary Venous Diameter of Dogs: A Transesophageal Echocardiography Study.

Q: What does this research mean for the field?

Inspiration significantly reduces the peak velocity and velocity-time integral of pulmonary venous flow during both systole and diastole compared to expiration in anesthetized dogs. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

CCChiang-Hua CHIANGKitasato University MHMitsuyoshi HagioUniversity of California, Los Angeles SOShozo OkanoKitasato University

Key Result

Inspiration significantly reduced the peak velocity and velocity-time integral of pulmonary venous flow during both systole and diastole compared to expiration in anesthetized dogs.

Study Design

Type

Observational (n=12)

Structured PICO

Does the respiratory cycle affect pulmonary venous flow and does the cardiac cycle affect pulmonary venous diameter in anesthetized dogs?

Population

12 anesthetized normal mongrel dogs, mean weight 7.71 ± 1.62 kg, 3 males and 9 females, estimated age 1-3 years old, with no evidence of cardiac or pulmonary abnormality.

Intervention

Transesophageal echocardiography (5 MHz biplane probe) under general anesthesia to assess pulmonary venous flow and diameter.

Comparator

Inspiration versus expiration for pulmonary venous flow; different phases of the cardiac cycle for pulmonary venous diameter.

Outcome

Peak velocity and velocity-time integral (VTI) of pulmonary venous flow during systole and diastole, and changes in pulmonary venous diameter during the cardiac cycle.surrogate

Respiration significantly affects pulmonary venous flow variables in anesthetized dogs, and pulmonary venous diameter varies dynamically during the cardiac cycle, suggesting caution when estimating flow volume using Doppler.

Abstract

We investigated 12 anesthetized normal dogs using transesophageal echocardiography to understand the effects of respiration on the pulmonary venous flow. Additionally, we observed whether the diameter of the pulmonary vein changes with the heart beat. The pulsed Doppler wave form of pulmonary venous flow predominantly demonstrated two backward flows, with one peak occurring during ventricular systole and another during ventricular diastole. Sometimes a small forward flow occurred during left atrial contraction. In comparison with expiration, the peak velocity and velocity-time integral of the flow wave under inspiration occurred during both systole and diastole were significantly smaller. The diameter of the pulmonary vein decreased during left atrial contraction and increased during left ventricular systole and diastole.

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