Pleural and extrapleural interstitial liquid pressure measured by cannulas and micropipettes

Miserocchi, G.; Kelly, Seth M.; Negrini, Daniela

doi:10.1152/jappl.1988.65.2.555

Cited by 20 publications

(15 citation statements)

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“…Similar values of Pes at FRC have been measured in the dog [17]. Our values of Ppl (-2.5 -+ 1.4 cm H20) at FRC were comparable with previous estimates (-2.4 -+ 0.7 cm H20) measured with the rib-capsule technique [16], but were more positive than values (between -4.0 and -5.2 cm H20 ) measured with intrapleural cannulas [1,15]. Changes in Pes might accurately reflect changes in pleural pressure, as observed during mechanical ventilation ( Table 2) but not during spontaneous breathing ( Table 1).…”

Section: Methodssupporting

confidence: 89%

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Pleural pressure measured in the zone of apposition of diaphragm to rib cage in rabbits

Pérez

Fernandez

Hernaiz

et al. 1993

Lung

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In 10 anesthetized adult rabbits, we studied the effect of spontaneous breathing and positive pressure ventilation on pleural pressure on the costal lung surface (Ppl) and in the zone of apposition of the rib cage to the diaphragm (Papp). Ppl and Papp were measured by rib capsules installed in the 5th or 6th rib and 11th or 12th rib, respectively. Esophageal (Pes) and gastric (Pga) pressures were measured with air-filled balloons. At end expiration (functional residual capacity), Ppl was subatmospheric (-2.5 +/- 1.4 cm H2O), decreased during spontaneous inspiration, and was in phase with Pes. In contrast, Papp was above atmospheric pressure (2.1 +/- 1.8 cm H2O), increased during inspiration, and was in phase with Pga. Papp lagged Ppl by 180 degrees during spontaneous inspiration but was in phase with Ppl during mechanical ventilation. Changes in Ppl (delta Ppl) during inspiration were greater in magnitude than either delta Papp or delta Pga. Changes in transdiaphragmatic pressure in the zone of apposition (delta Pga-delta Papp) were near zero (-0.4 +/- 0.3 cm H2O), much smaller in magnitude than those (delta Pga-delta Ppl) associated with the lung (3.0 +/- 1.5 cm H2O). These results are consistent with the concept that during breathing, abdominal pressure is transmitted to the zone of apposition of the rib cage to the abdomen. During spontaneous breathing at rest, the pleural space in the zone of apposition is mechanically independent of the pleural space associated with the lung.

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Section: Methodssupporting

confidence: 89%

“…With this assumption we ignored the vertical gradient in pleural pressure present in the left lateral position [1,8,15,16].…”

Section: Methodsmentioning

confidence: 99%

Pleural pressure measured in the zone of apposition of diaphragm to rib cage in rabbits

Pérez

Fernandez

Hernaiz

et al. 1993

Lung

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“…The end-expiratory P1iq values from the present study are similar to those previously obtained in rabbits with intrapleural cannulae (Miserocchi et al 1982) and micropipettes (Miserocchi et al 1988a), yet they are significantly more negative than those obtained with the 'rib capsule' technique in the rabbit (Yang et al 1989 (Albertine, Wiener-Kronish, Bastacky & Staub, 1991) they are likely to occur on a functional basis (Grotberg & Glucksberg, 1994). In fact simultaneous measurements of Pliq and Pp1 (Miserocchi,Nakamura & Agostoni,198 la), indicate that the former is more subatmospheric than the latter at any height.…”

Section: Intercostal and Costal Tubes For Pliq Measurementsupporting

confidence: 91%

An improved technique for studying pleural fluid pressure and composition in rabbits

Fabbro¹

1998

Experimental Physiology

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SUMMARYKnowledge of pleural liquid pressure (Plij) and composition is crucial for studies concerning intrapleural fluid dynamics, and pleural fluid turnover. We measured Pli at intercostal and costal levels in anaesthetized spontaneously breathing rabbits using a minimally invasive method that assures a long-lasting hydraulic continuity between the pleural liquid and the recording system. Polyethylene tubes were glued either to the exposed endothoracic fascia or inserted into a rib to provide a sealed connection to the recording system. After inducing a pneumothorax with nitrous oxide (N20) via an intrapleural cannula, a hole (-07 mm2) was pierced in the parietal pleura through the tube lumen. The tubes were then connected to pressure transducers and the whole system was filled with heparinized saline to the level of the parietal pleura; finally the pneumothorax was removed after N20 washout and Pliq recordings were performed. A different kind of tube was used to obtain microsamples of pleural fluid (2-5-3 1I) during spontaneous breathing; colloid osmotic pressure of the microsamples (H1j) was measured with an osmometer, and averaged 9-3 + 1.5 cmH2O (n = 70 samples). When pooled and plotted against lung height endexpiratory intercostal and costal P1I, data scattered along a single regression line with a slope of -0-83 and -0-90 cmH2O cm-' in supine and prone animals, respectively. End-inspiratory costal P1I0 was significantly more subatmospheric than intercostal in the ventral region of the chest (P < 0.05), and less subatmospheric in the dorsal region, regardless of posture. The techniques presented here could be helpful in gaining a greater insight into the physiology and pathophysiology of the pleural space in terms of pleural fluid dynamics and turnover.

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“…Pint in the subpleural interstitium of the lung was estimated to be -8 cmH 2 [63]. Pint measurements, however, were made y200 mm deep to the mesothelium [85,86]: they, therefore, refer to extrapleural parietal and visceral interstitia, and may not reflect pressures occurring between mesothelium and pleural capillaries, which are only 10-50 mm apart in most species [35]. The value attributed to the visceral pleura [86] pertains to lung parenchyma, because rabbit visceral pleura is v20 mm thick, and the alveoli are only 30-40 mm below the lung surface.…”

Section: Transpleural Pressuresmentioning

confidence: 99%

Physiology and pathophysiology of pleural fluid turnover

Zocchi¹

2002

Eur Respir J

183

102

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Tight control of the volume and composition of the pleural liquid is necessary to ensure an efficient mechanical coupling between lung and chest wall. Liquid enters the pleural space through the parietal pleura down a net filtering pressure gradient. Liquid removal is provided by an absorptive pressure gradient through the visceral pleura, by lymphatic drainage through the stomas of the parietal pleura, and by cellular mechanisms. Indeed, contrary to what was believed in the past, pleural mesothelial cells are metabolically active, and possess the cellular features for active transport of solutes, including vesicular transport of protein. Furthermore, the mesothelium was shown, on the basis of recent experimental evidence, both in vivo and in vitro, to be a less permeable barrier than previously believed, being provided with permeability characteristics similar to those of the microvascular endothelium. Direct assessment of the relative contribution of the different mechanisms of pleural fluid removal is difficult, due to the difficulty in measuring the relevant parameters in the appropriate areas, and to the fragility of the mesothelium. The role of the visceral pleura in pleural fluid removal under physiological conditions is supported by a number of findings and considerations.Further evidence indicates that direct lymphatic drainage through the stomas of the parietal pleura is crucial in removing particles and cells, and important in removing protein from the pleural space, but should not be the main effector of fluid removal. Its importance, however, increases markedly in the presence of increased intrapleural liquid loads. Removal of protein and liquid by transcytosis, although likely on the basis of morphological findings and suggested by recent indirect experimental evidence, still needs to be directly proven to occur in the pleura. When pleural liquid volume increases, an imbalance occurs in the forces involved in turnover, which favours fluid removal. In case of a primary abnormality of one ore more of the mechanisms of pleural liquid turnover, a pleural effusion ensues. The factors responsible for pleural effusion may be subdivided into three main categories: those changing transpleural pressure balance, those impairing lymphatic drainage, and those producing increases in mesothelial and capillary endothelial permeability. Except in the first case, pleural fluid protein concentration increases above normal: this feature underlies the classification of pleural effusions into transudative and exudative. Eur Respir J 2002; 20: 1545-1558. The thin layer of liquid present between the pleural surfaces has the important function of providing the mechanical coupling between the chest wall and lung, which ensures instantaneous transmission of perpendicular forces between the two structures, and allows their sliding in response to shearing forces [1,2]. It also provides lubrication of the reciprocal motions of the two structures during breathing. Two views, in part compatible, exist on the nature of t...

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Pleural and extrapleural interstitial liquid pressure measured by cannulas and micropipettes

Cited by 20 publications

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Pleural pressure measured in the zone of apposition of diaphragm to rib cage in rabbits

Pleural pressure measured in the zone of apposition of diaphragm to rib cage in rabbits

An improved technique for studying pleural fluid pressure and composition in rabbits

Physiology and pathophysiology of pleural fluid turnover

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