Positive End-expiratory Pressure Redistributes Regional Blood Flow and Ventilation Differently in Supine and Prone Humans

Petersson, Johan; Ax, Malin; Frey, Jakob; Sánchez-Crespo, Alejandro; Lindahl, Sten G. E.; Mure, Margareta

doi:10.1097/aln.0b013e3181fcec4f

Cited by 44 publications

(32 citation statements)

References 34 publications

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“…This was in accordance with earlier work by Mure et al (Mure et al, 2000) in pigs and Musch et al (Musch et al, 2002) in man. The uni-modal vertical ventilation gradient in supine position was reproduced by two recent SPECT studies in supine and prone anaesthetised and mechanically ventilated humans (Nyrén et al, 2010 andPetersson et al, 2010). However, the distribution in prone position differed.…”

Section: Redistribution Of Ventilation By Peep and Positionmentioning

confidence: 57%

“…This pattern, however, was not present in two studies in anaesthetised mechanically ventilated humans where a vertical V/Q gradient with increasing V/Q from nondependent to dependent lung was found (Nyrén et al, 2010 andPetersson et al, 2010). 10 and 20 cmH 2 O PEEP, applied in the prone position in Paper III, preserved the homogeneous distribution of V/Q without creating non-dependent regions with a high V/Q (here V/Q > 3.0).…”

Section: Effects Of Peep and Positionmentioning

confidence: 85%

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Gas Exchange in the Normal Lung : Experimental studies on the effects of positive end-expiratory pressure and body position

Johansson¹

2014

Linköping University Medical Dissertations

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BACKGROUND:The principal function of the lung is gas exchange requiring adequate ventilation and perfusion at the level of the alveoli. The efficiency of gas exchange is depending on the distributions of regional ventilation (V) and pulmonary blood flow (Q) and their correlation. AIMS:To validate a high-resolution method to quantify regional V and to investigate the Radioactive microspheres, 15 m in diameter, were used for determining regional Q. Nitric oxide synthase (NOS) was inhibited with Nω-nitro-L-arginine methyl ester (L-NAME) to evaluate the role of NO on regional V/Q matching. The right lung was dried at total lung capacity and diced in approx. 1000 regions tracking the spatial location of each region. CONCLUSION: There were marked differences in redistribution of regional ventilation and regional pulmonary blood flow between prone and supine position when PEEP was applied. RESULTS:NO was not an active mechanism for V/Q matching in normal sheep lungs. VII List of original papershis thesis is based on the following four papers, which will be referred to by their Roman numerals: I.Positive end-expiratory pressure affects regional redistribution of ventilation differently in prone and supine sheep.

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Section: Redistribution Of Ventilation By Peep and Positionmentioning

confidence: 57%

Section: Effects Of Peep and Positionmentioning

confidence: 85%

Gas Exchange in the Normal Lung : Experimental studies on the effects of positive end-expiratory pressure and body position

Johansson¹

2014

Linköping University Medical Dissertations

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“…Toutefois, si une pression expiratoire positive (PEEP) de plus de 10 cm H 2 O est appliquée, le flux sanguin se redistribue des zones dorsales à ventrales, ce qui augmente le décalage V/Q et provoque une réduction paradoxale de l'oxygénation artérielle. 3 La plupart du temps, chez un patient sain sous anesthésie en position ventrale, la réduction de l'oxygénation artérielle n'a aucune incidence clinique; par conséquent, le recours An update on the prone position 753 • Bon marché…”

Section: Les Changements Physiologiques Associés à La Position Ventraleunclassified

“…However, if positive end-expiratory pressure (PEEP) is applied ([10 cm H 2 O), blood flow is further redistributed from the dorsal to the ventral areas, increasing V/Q mismatch and resulting in a paradoxical reduction in arterial oxygenation. 3 The reduction in arterial oxygenation is often clinically insignificant in healthy anesthetized patients positioned prone, and the routine use of PEEP is unnecessary and not recommended for the majority of anesthetized patients in the prone position.…”

Section: Physiological Changes Associated With the Prone Positionmentioning

confidence: 99%

An update on the prone position: Continuing Professional Development

Chui

Craen

2016

Can J Anesth/J Can Anesth

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Purpose The purpose of this Continuing Professional Development module is to provide information needed to prepare for and clinically manage a patient in the prone position. Principal findings Prone positioning is required for surgical procedures that involve the posterior aspect of a patient. We searched MEDLINE Ò and EMBASE TM from January 2000 to January 2015 for literature related to the prone position and retrieved only original articles in English. We reviewed the advantages and disadvantages of various equipment used in prone positioning, the physiological changes associated with prone positioning, and the complications that can occur. We also reviewed strategies for the safe conduct and management of position-related complications. Conclusion Increased age, elevated body mass index, the presence of comorbidities, and long duration of surgery appear to be the most important risk factors for complications associated with prone positioning. We recommend a structured team approach and careful selection of equipment tailored to the patient and surgery. The systematic use of checklists is recommended to guide operating room teams and to reduce prone position-related complications. Anesthesiologists should be prepared to manage major intraoperative emergencies (e.g., accidental extubation) and anticipate postoperative complications (e.g., airway edema and visual loss).

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“…When patients are placed in the prone position, the chest wall compliance decreases, and the P TP is redistributed from dorsal to ventral and, as a consequence, there is a recruitment of pulmonary dorsal regions, which directly reflects the improvement in patient's oxygenation [10][11][12] . By promoting a more balanced ventilation associated with recruitment, the prone position also results in a better distribution of blood flow 13 , preventing its inappropriate redirection from hyperinflated areas to the collapsed ones in response to increased average airway pressure and positive end-expiratory pressure (PEEP) 14,15 . In addition to direct effects, studies show that the ventilation in prone protects from, or at least slows the development of, injuries associated with mechanical ventilation 16 .…”

Section: Methods Methods Methods Methodsmentioning

confidence: 99%

Pulmonar recruitment in acute respiratory distress syndrome. What is the best strategy?

Santos

Samary

Júnior

et al. 2015

Rev. Col. Bras. Cir.

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Supporting patients with acute respiratory distress syndrome (ARDS), using a protective mechanical ventilation strategy characterized by low tidal volume and limitation of positive end-expiratory pressure (PEEP) is a standard practice in the intensive care unit. However, these strategies can promote lung de-recruitment, leading to the cyclic closing and reopening of collapsed alveoli and small airways. Recruitment maneuvers (RM) can be used to augment other methods, like positive end-expiratory pressure and positioning, to improve aerated lung volume. Clinical practice varies widely, and the optimal method and patient selection for recruitment maneuvers have not been determined, considerable uncertainty remaining regarding the appropriateness of RM. This review aims to discuss recent findings about the available types of RM, and compare the effectiveness, indications and adverse effects among them, as well as their impact on morbidity and mortality in ARDS patients. Recent developments include experimental and clinical evidence that a stepwise extended recruitment maneuver may cause an improvement in aerated lung volume and decrease the biological impact seen with the traditionally used sustained inflation, with less adverse effects. Prone positioning can reduce mortality in severe ARDS patients and may be an useful adjunct to recruitment maneuvers and advanced ventilatory strategies, such noisy ventilation and BIVENT, which have been useful in providing lung recruitment.

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Positive End-expiratory Pressure Redistributes Regional Blood Flow and Ventilation Differently in Supine and Prone Humans

Cited by 44 publications

References 34 publications

Gas Exchange in the Normal Lung : Experimental studies on the effects of positive end-expiratory pressure and body position

Gas Exchange in the Normal Lung : Experimental studies on the effects of positive end-expiratory pressure and body position

An update on the prone position: Continuing Professional Development

Pulmonar recruitment in acute respiratory distress syndrome. What is the best strategy?

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