Analysis of Longitudinal Distribution of Pulmonary Vascular Resistance by Use of a Five Element Lumped Model.

Kondo, Motoki; Washizu, Makoto; Matsukura, Yoshihito; Kobayashi, Kunito; Motoyoshi, Shigekatsu; Miyasaka, Katsuyuki; Takata, Masao

doi:10.1292/jvms.56.71

Cited by 2 publications

(6 citation statements)

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“…The usefulness of the five element lumped model has been proven in normal lung [2][3][4]16] to analyze the longitudinal distribution of vascular resistance. However, this model has not been applied to HWI lungs.…”

Section: Discussionmentioning

confidence: 99%

“…The isolated lung lobe preparation has been described previously [4]. In brief, after measuring PVR, each dog was heparinized (200 U/kg, iv) and approximately 350 ml of arterial blood was removed via the catheters in the femoral and carotid arteries to prime an extracorporeal perfusion system as illustrated in Fig.…”

Section: Isolated Perfused Lung Lobementioning

confidence: 99%

“…1). The vascular occlusion technique is a method for analysis of resistance distribution based on a five element lumped model [4] (Fig. 2).…”

Section: Isolated Perfused Lung Lobementioning

confidence: 99%

“…An electrical analog of the five-element lumped model utilized in this study. Details of the model were described previously [4]. Pu, Pa, Pv, and Pd are upstream, pulmonary arterial, pulmonary venous, and downstream pressures, respectively.…”

Section: Isolated Perfused Lung Lobementioning

confidence: 99%

“…In addition, arterial and venous occlusion techniques were used at each perfusing flow to compare the longitudinal distributions of pulmonary vascular resistance in normal and HWI lungs [2][3][4]16]. Evaluation of pressure-flow curve and distribution of pulmonary vascular resistance would allow us to understand the characteristics of vascular behavior of HWI lung in response to increased cardiac output.…”

mentioning

confidence: 99%

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Pressure-Flow Relationship and Longitudinal Distribution of Pulmonary Vascular Resistance in Heartworm-Infected Dogs

Kondo

Washizu

Matsukura

et al. 2003

The Journal of Veterinary Medical Science

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ABSTRACT. The pressure-flow relationships and the longitudinal distributions of pulmonary vascular resistance in normal and heartworminfected (HWI) dogs were compared in an isolated, blood perfused preparation. The pulmonary circulation was partitioned into pulmonary arterial, middle, and venous segment based on the concept of a five element lumped model. The pulmonary arterial pressure-flow relationships were found to be non-linear and convex to the pressure axis in both normal and HWI lungs. The pressure-flow relationships of the pulmonary arterial and venous segment were linear and these slopes in the HWI lungs were significantly higher than the normal lungs. The pressure gradient of the middle segment was increased as flow increased at lower flow range, however, it was not increased during higher perfusion range in both lungs. At higher flow, the pressure gradient of the middle segment in the HWI lungs was significantly higher than the normal lungs. These results suggest that the ohmic resistance was almost equal to the sum of the two slopes of the pressure-flow relationships of the pulmonary arterial and venous segment because the pressure gradient of the middle segment was not altered as flow increased during higher perfusion rate. Because the slopes of the pressure-flow relationships of the pulmonary arterial and venous segment were increased with heartworm infection, the ohmic resistance of HWI lungs would be higher than normal lungs. The intercept pressure on the pressure axis of the linear portion of the pulmonary arterial pressure-flow relationship, a critical closing pressure, was regarded as pressure gradient of the middle segment during higher perfusing rate because the intercept pressures of pressure-flow relationships of pulmonary arterial and venous segment were almost equal to zero. Therefore, the critical closing pressure of HWI lungs would be higher than normal lungs. The pulmonary hypertension of filariasis appears to be due to an increase in ohmic resistance and elevated critical closing pressure. KEY WORDS: canine, filariasis, pressure-flow relationship, pulmonary vascular resistance, vascular occlusion technique.J. Vet. Med. Sci. 65(9): 965-970, 2003 In normal dogs, an increase in pulmonary blood flow is associated with a decrease in pulmonary vascular resistance without a marked elevation in pulmonary arterial pressure [14,15]. The reduction in pulmonary vascular resistance is generally considered to be due to capillary recruitment and/ or dilatation [6,19]. In dogs with heartworm disease, however, the reduction in pulmonary vascular resistance that accompanies an increase in cardiac output is smaller in magnitude than normal dogs [12,13]. The capillary bed in heartworm-infected (HWI) dogs may not be able to recruit and/or dilate efficiently with the increase in cardiac output [14,15]. The behaviors of the pulmonary vasculature in HWI dogs in response to increases in cardiac output have not been well studied.In this study, pressure-flow curves at different perfusing flows were obtaine...

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Section: Discussionmentioning

confidence: 99%

Section: Isolated Perfused Lung Lobementioning

confidence: 99%

“…1). The vascular occlusion technique is a method for analysis of resistance distribution based on a five element lumped model [4] (Fig. 2).…”

Section: Isolated Perfused Lung Lobementioning

confidence: 99%

Section: Isolated Perfused Lung Lobementioning

confidence: 99%

mentioning

confidence: 99%