Effects of PEEP on liver arterial and venous blood flows.

Brienza, Nicola; Revelly, Jean Pierre; Ayuse, Takao; Robotham, James L.

doi:10.1164/ajrccm.152.2.7633699

Cited by 92 publications

(60 citation statements)

References 30 publications

(45 reference statements)

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“…Other possible mechanisms for the drop in Q VR include increased resistance to venous return and decrease the maximal value of venous return (increased Pcrit) [16,18] due to venous geometry distortion at the entrance of the venae cavae into the thorax [19] or further upstream in the portal circulation (i.e. compression of the liver by diaphragmatic descent) [20]. Geometric alteration of the inferior vena cava (ICV) at its point of entry the thorax is not restricted to positive pressure ventilation.…”

Section: Lung Inflation and Hemodynamicsmentioning

confidence: 99%

Cardiopulmonary interactions and volume status assessment

Broccard

2012

J Clin Monit Comput

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Assessment of the hemodynamics and volume status is an important daily task for physicians caring for critically ill patients. There is growing consensus in the critical care community that the "traditional" methods-e.g., central venous pressure or pulmonary artery occlusion pressure-used to assess volume status and fluid responsiveness are not well supported by evidence and can be misleading. Our purpose is to provide here an overview of the knowledge needed by ICU physicians to take advantage of mechanical cardiopulmonary interactions to assess volume responsiveness. Although not perfect, such dynamic assessment of fluid responsiveness can be helpful particularly in the passively ventilated patients. We discuss the impact of phasic changes in lung volume and intrathoracic pressure on the pulmonary and systemic circulation and on the heart function. We review how respirophasic changes on the venous side (great veins geometry) and arterial side (e.g., stroke volume/systolic blood pressure and surrogate signals) can be used to detect fluid responsiveness or hemodynamic alterations commonly encountered in the ICU. We review the physiological limitations of this approach.

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Section: Lung Inflation and Hemodynamicsmentioning

confidence: 99%

Cardiopulmonary interactions and volume status assessment

Broccard

2012

J Clin Monit Comput

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“…This compression is independent from any effect on the generalized abdominal pressure produced by diaphragmatic descent, since it also occurs with an open abdomen [50]. The compression on the liver surface from the downward displacement of the diaphragm could reduce the diameter and/or the number of the perfused sinusoidal channels, and cause an increase in splanchnic venous resistance, and a decrease in splanchnic venous return [51], simulating an abdominal zone III. However, MURCIANO et al [52] showed that in most COPD patients, there is little change in gastric pressure during spontaneous respiration.…”

Section: Abdominal Pressurementioning

confidence: 99%

Intrinsic PEEP and cardiopulmonary interaction in patients with COPD and acute ventilatory failure

Dambrosio¹,

Brienza²

1996

Eur Respir J

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Intrinsic PEEP and cardiopulmonary interaction in patients with COPD and acute ventilatory failure. V.M. Ranieri, M. Dambrosio, N. Brienza. ERS Journals Ltd 1996. ABSTRACT: Deviation of end-expiratory lung volume from the elastic equilibrium volume of the respiratory system is recognized as a cardinal feature in mechanically-ventilated patients with severe chronic obstructive pulmonary disease (COPD) and acute ventilatory failure (AVF). The presence of dynamic hyperinflation implies that alveolar pressure remains positive throughout expiration. At the end of the expiration, this positive pressure is named intrinsic positive end-expiratory pressure (PEEPi).Recent studies have suggested that, in COPD patients with expiratory flow limitation, the application of external PEEP during assisted mechanical ventilation, or the use of continuous positive airway pressure (CPAP) in spontaneously breathing patients, can counterbalance and reduce the inspiratory threshold load imposed by PEEPi, without causing further increase in lung volume and alveolar and intrathoracic pressures until a critical value of PEEP (Pcrit) is reached. Above this critical limit further hyperinflation is observed.A specific and characteristic role of PEEPi in compromising the heart function in COPD patients during AVF may be identified based on: 1) an increase in right ventricular impedance due to lung hyperinflation; 2) an increase in the venous return to the right ventricle and, consequently, a leftward shift of the septum caused by the large negative deflections in intrathoracic pressure due to the inspiratory threshold load; 3) a further increase in venous return to the right ventricle, with the eventual collapse of the vena cava caused by the expiratory recruitment of abdominal muscles; and 4) hypoxia and hypercapnia consequent to acute ventilatory failure, which may further increase right ventricular impedance and venous return to the right ventricle.All these phenomenon are directly correlated to the large negative intrathoracic pressure developed by the respiratory muscles to overcome the inspiratory threshold caused by intrinsic positive end-expiratory pressure (preload effect), and to the increase in lung volume (afterload effect). Application of positive end-expiratory pressure/continuous positive airway pressure in chronic obstructive pulmonary disease patients during acute ventilatory failure may, hence, unload the respiratory muscles as well as the heart. Eur Respir J., 1996Respir J., , 9, 1283Respir J., -1292

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“…The decrease in CO is accompanied by an increase in heart rate and a decrease in arterial pressure [30, 33]. Meanwhile, the rise in intra-alveolar pressure, the subsequent rise in pulmonary vascular resistances and difficulties with venous return precipitate increases in CVP [11, 31]and venous portal pressure [6, 8, 15, 21]. In effect, a state of relative hypovolaemia [9]is produced with PEEP.…”

Section: Discussionmentioning

confidence: 99%

“…However, these favourable effects are accompanied by the haemodynamic side effects of increased intrathoracic pressure and reduction in cardiac output (CO) [30, 37, 39]. Reduction in hepatic [8, 15, 41], renal and gastric fundal [4, 31]blood flow has been demonstrated, but little is known about its effects on gastrointestinal parietal perfusion or oxygen delivery, nor about its implications in anastomotic healing.…”

Section: Introductionmentioning

confidence: 99%

Effects of PEEP on Residual Vascularization in Oesophageal Substitution Gastroplasty by Surface Oximetry-Capnometry and Photoplethysmography

Uribe¹,

García‐Granero²,

Millán³

et al. 2003

Dig Surg

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Objective: To evaluate the effects of positive end-expiratory pressure (PEEP) on residual vascularization in gastric tubes for oesophageal replacement. Design: Experimental open study. Materials: Eleven mongrel dogs. Methods: Intestinal parietal blood flow was evaluated by photoplethysmography (PPG) and measurement of surface oxygen (PsO₂) and carbon dioxide (PsCO₂) tensions under basal conditions. After Akiyama’s tubular gastroplasty, three levels of PEEP were administered. At each level, fluids were infused to counter the drop in cardiac output. PPG, surface gas tensions, arterial pressure, cardiac output and arterial blood gas tensions were monitored. Control sections of the bowel were also monitored by PPG. Results: Cardiac output dropped for each level of PEEP and returned to basal levels on volume restabilization and on removal of PEEP. Central venous pressure and pulmonary arterial and capillary pressures increased for each level of PEEP and only returned to basal levels on removal of PEEP. PsO₂ values dropped for each level of PEEP and returned to basal levels on volume restabilization and on removal of PEEP. PsCO₂ levels rose, and PPG wave amplitude dropped, for each level of PEEP; these two variables only returned to basal levels on removal of PEEP. PPG values for the control sections reflected those of the anastomotic area. Conclusions: PEEP affects surface oxygen values at the level of the gastroplasty by means of its effect on cardiac output. PEEP also creates a venous return compromise and PPG wave amplitude and surface carbon dioxide values are related to this compromise. All three variables could be significant in anastomotic wound healing.

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Effects of PEEP on liver arterial and venous blood flows.

Cited by 92 publications

References 30 publications

Cardiopulmonary interactions and volume status assessment

Cardiopulmonary interactions and volume status assessment

Intrinsic PEEP and cardiopulmonary interaction in patients with COPD and acute ventilatory failure

Effects of PEEP on Residual Vascularization in Oesophageal Substitution Gastroplasty by Surface Oximetry-Capnometry and Photoplethysmography

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