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Tonetti T, Cavalli I, Ranieri VM, Mascia L. Respiratory consequences of intra-abdominal hypertension. Minerva Anestesiol 2020; 86:877-883. [DOI: 10.23736/s0375-9393.20.14325-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Marchesi S, Hedenstierna G, Hata A, Feinstein R, Larsson A, Larsson AO, Lipcsey M. Effect of mechanical ventilation versus spontaneous breathing on abdominal edema and inflammation in ARDS: an experimental porcine model. BMC Pulm Med 2020; 20:106. [PMID: 32334550 PMCID: PMC7183610 DOI: 10.1186/s12890-020-1138-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 04/07/2020] [Indexed: 11/18/2022] Open
Abstract
Background Mechanical ventilation (MV), compared to spontaneous breathing (SB), has been found to increase abdominal edema and inflammation in experimental sepsis. Our hypothesis was that in primary acute respiratory distress syndrome (ARDS) MV would enhance inflammation and edema in the abdomen. Methods Thirteen piglets were randomized into two groups (SB and MV) after the induction of ARDS by lung lavage and 1 h of injurious ventilation. 1. SB: continuous positive airway pressure 15 cmH2O, fraction of inspired oxygen (FIO2) 0.5 and respiratory rate (RR) maintained at about 40 cycles min− 1 by titrating remifentanil infusion. 2. MV: volume control, tidal volume 6 ml kg− 1, positive end-expiratory pressure 15 cmH2O, RR 40 cycles min− 1, FIO2 0.5. Main outcomes: abdominal edema, assessed by tissues histopathology and wet-dry weight; abdominal inflammation, assessed by cytokine concentration in tissues, blood and ascites, and tissue histopathology. Results The groups did not show significant differences in hemodynamic or respiratory parameters. Moreover, edema and inflammation in the abdominal organs were similar. However, blood IL6 increased in the MV group in all vascular beds (p < 0.001). In addition, TNFα ratio in blood increased through the lungs in MV group (+ 26% ± 3) but decreased in the SB group (− 17% ± 3). Conclusions There were no differences between the MV and SB group for abdominal edema or inflammation. However, the systemic increase in IL6 and the TNFα increase through the lungs suggest that MV, in this model, was harmful to the lungs.
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Affiliation(s)
- Silvia Marchesi
- Hedenstierna Laboratory, Department of Surgical Sciences, Uppsala University, 75185, Uppsala, Sweden.
| | - Göran Hedenstierna
- Department of Medical Sciences, Clinical Physiology, Uppsala University, Uppsala, Sweden
| | - Aki Hata
- Hedenstierna Laboratory, Department of Surgical Sciences, Uppsala University, 75185, Uppsala, Sweden
| | | | - Anders Larsson
- Hedenstierna Laboratory, Department of Surgical Sciences, Uppsala University, 75185, Uppsala, Sweden
| | - Anders Olof Larsson
- Section of Clinical Chemistry, Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Miklós Lipcsey
- Hedenstierna Laboratory, Department of Surgical Sciences, Uppsala University, 75185, Uppsala, Sweden
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Comuzzi L, de Abreu MB, Motta-Ribeiro GC, Okuro RT, Barboza T, Carvalho N, Lucangelo U, Carvalho AR, Zin WA. Regional Lung Recruitability During Pneumoperitoneum Depends on Chest Wall Elastance - A Mechanical and Computed Tomography Analysis in Rats. Front Physiol 2018; 9:920. [PMID: 30057557 PMCID: PMC6053523 DOI: 10.3389/fphys.2018.00920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 06/25/2018] [Indexed: 11/13/2022] Open
Abstract
Background: Laparoscopic surgery with pneumoperitoneum increases respiratory system elastance due to the augmented intra-abdominal pressure. We aim to evaluate to which extent positive end-expiratory pressure (PEEP) is able to counteract abdominal hypertension preventing progressive lung collapse and how rib cage elastance influences PEEP effect. Methods: Forty-four Wistar rats were mechanically ventilated and randomly assigned into three groups: control (CTRL), pneumoperitoneum (PPT) and pneumoperitoneum with restricted rib cage (PPT-RC). A pressure-volume (PV) curve followed by a recruitment maneuver and a decremental PEEP trial were performed in all groups. Thereafter, animals were ventilated using PEEP of 3 and 8 cmH2O divided into two subgroups used to evaluate respiratory mechanics or computed tomography (CT) images. In 26 rats, we compared respiratory system elastance (Ers) at the two PEEP levels. In 18 animals, CT images were acquired to calculate total lung volume (TLV), total volume and air volume in six anatomically delimited regions of interest (three along the cephalo-caudal and three along the ventro-dorsal axes). Results: PEEP of minimal Ers was similar in CTRL and PPT groups (3.8 ± 0.45 and 3.5 ± 3.89 cmH2O, respectively) and differed from PPT-RC group (9.8 ± 0.63 cmH2O). Chest restriction determined a right- and downward shift of the PV curve, increased Ers and diminished TLV and lung aeration. Increasing PEEP augmented TLV in CTRL group (11.8 ± 1.3 to 13.6 ± 2 ml, p < 0.05), and relative air content in the apex of PPT group (3.5 ± 1.4 to 4.6 ± 1.4% TLV, p < 0.03) and in the middle zones in PPT-RC group (21.4 ± 1.9 to 25.3 ± 2.1% TLV cephalo-caudally and 18.1 ± 4.3 to 22.0 ± 3.3% TLV ventro-dorsally, p < 0.005). Conclusion: Regional lung recruitment potential during pneumoperitoneum depends on rib cage elastance, reinforcing the concept of PEEP individualization according to the patient's condition.
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Affiliation(s)
- Lucia Comuzzi
- Laboratory of Respiration Physiology, Carlos Chagas Filho Institute of Biophysics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Department of Perioperative Medicine, Intensive Care and Emergency, Università degli Studi di Trieste, Trieste, Italy
| | - Mariana B de Abreu
- Laboratory of Respiration Physiology, Carlos Chagas Filho Institute of Biophysics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Gabriel C Motta-Ribeiro
- Laboratory of Pulmonary Engineering, Alberto Luiz Coimbra Institute of Post-Graduation and Engineering Research, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Renata T Okuro
- Laboratory of Respiration Physiology, Carlos Chagas Filho Institute of Biophysics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Thiago Barboza
- National Center for Structural Biology and Bioimaging, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Niedja Carvalho
- Laboratory of Pulmonary Engineering, Alberto Luiz Coimbra Institute of Post-Graduation and Engineering Research, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Umberto Lucangelo
- Department of Perioperative Medicine, Intensive Care and Emergency, Università degli Studi di Trieste, Trieste, Italy
| | - Alysson R Carvalho
- Laboratory of Respiration Physiology, Carlos Chagas Filho Institute of Biophysics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Laboratory of Pulmonary Engineering, Alberto Luiz Coimbra Institute of Post-Graduation and Engineering Research, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Walter A Zin
- Laboratory of Respiration Physiology, Carlos Chagas Filho Institute of Biophysics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Doras C, Le Guen M, Peták F, Habre W. Cardiorespiratory effects of recruitment maneuvers and positive end expiratory pressure in an experimental context of acute lung injury and pulmonary hypertension. BMC Pulm Med 2015; 15:82. [PMID: 26228052 PMCID: PMC4521467 DOI: 10.1186/s12890-015-0079-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 07/20/2015] [Indexed: 01/17/2023] Open
Abstract
Background Recruitment maneuvers (RM) and positive end expiratory pressure (PEEP) are the cornerstone of the open lung strategy during ventilation, particularly during acute lung injury (ALI). However, these interventions may impact the pulmonary circulation and induce hemodynamic and respiratory effects, which in turn may be critical in case of pulmonary hypertension (PHT). We aimed to establish how ALI and PHT influence the cardiorespiratory effects of RM and PEEP. Methods Rabbits control or with monocrotaline-induced PHT were used. Forced oscillatory airway and tissue mechanics, effective lung volume (ELV), systemic and right ventricular hemodynamics and blood gas were assessed before and after RM, during baseline and following surfactant depletion by whole lung lavage. Results RM was more efficient in improving respiratory elastance and ELV in the surfactant-depleted lungs when PHT was concomitantly present. Moreover, the adverse changes in respiratory mechanics and ELV following ALI were lessened in the animals suffering from PHT. Conclusions During ventilation with open lung strategy, the role of PHT in conferring protection from the adverse respiratory consequences of ALI was evidenced. This finding advocates the safety of RM and PEEP in improving elastance and advancing lung reopening in the simultaneous presence of PHT and ALI.
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Affiliation(s)
- Camille Doras
- Anesthesiological Investigation, University Medical Centre, University of Geneva, Geneva, Switzerland.
| | - Morgan Le Guen
- Department of Anesthesiology, Hospital Foch, University Versailles Saint-Quentin en Yvelines, Suresnes, France.
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary.
| | - Walid Habre
- Anesthesiological Investigation, University Medical Centre, University of Geneva, Geneva, Switzerland. .,Pediatric Anesthesia Unit, Geneva Children's Hospital, Rue Willy Donzé 6, 1205, Geneva, Switzerland.
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Turkoglu M, Bostancı EB, Bilgili H, Türkoğlu Y, Karadeniz Ü, Aydoğ G, Erçin U, Bilgihan A, Özer İ, Akoğlu M. Effect of intraoperative PEEP application on colonic anastomoses healing: An experimental animal study. Int Surg 2015; 101:24-34. [PMID: 26215540 DOI: 10.9738/intsurg-d-15-00160.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024] Open
Abstract
PURPOSE This study aimed to assess the effect of intraoperative PEEP intervention on the healing of colonic anastomoses in rabbits. MATERIALS AND METHODS Thirty-two New Zealand type male rabbits were divided into two groups of sixteen animals each. Following ventilation with tracheostomy, colonic resection and anastomosis were performed in both groups. While 10 cm H2O PEEP level was applied in Group I (PEEP), Group II (ZEEP) was ventilated without PEEP throughout the surgery. Half of the both PEEP and ZEEP group animals were killed on the third postoperative day, while the remaining half on the seventh. Anastomotic bursting pressures, the tissue concentrations in hydroxyproline, and histological assessments were performed. Besides, intraoperative oxygen saturation and postoperative arterial blood gas parameters were also compared. RESULTS On the first postoperative day, both arterial oxygen tension (PO2) and oxygen saturation (SO2) in the PEEP group were significantly higher than in the ZEEP group. On the seventh postoperative day, the bursting pressures of the anastomoses were significantly higher in the PEEP group, however the hydroxyproline content was significantly lower in the PEEP group than that in the ZEEP group. At day 7, PEEP group was significantly associated with increased neoangiogenesis compared with the ZEEP group. CONCLUSION The anastomotic healing process is positively influenced by the intraoperative PEEP application.
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Affiliation(s)
- Mehmet Turkoglu
- Akdeniz University, Faculty of Medicine, Antalya, 07058, Turkey
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Loring SH, Behazin N, Novero A, Novack V, Jones SB, O'Donnell CR, Talmor DS. Respiratory mechanical effects of surgical pneumoperitoneum in humans. J Appl Physiol (1985) 2014; 117:1074-9. [PMID: 25213641 DOI: 10.1152/japplphysiol.00552.2014] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pneumoperitoneum for laparoscopic surgery is known to stiffen the chest wall and respiratory system, but its effects on resting pleural pressure in humans are unknown. We hypothesized that pneumoperitoneum would raise abdominal pressure, push the diaphragm into the thorax, raise pleural pressure, and squeeze the lung, which would become stiffer at low volumes as in severe obesity. Nineteen predominantly obese laparoscopic patients without pulmonary disease were studied supine (level), under neuromuscular blockade, before and after insufflation of CO2 to a gas pressure of 20 cmH2O. Esophageal pressure (Pes) and airway pressure (Pao) were measured to estimate pleural pressure and transpulmonary pressure (Pl = Pao - Pes). Changes in relaxation volume (Vrel, at Pao = 0) were estimated from changes in expiratory reserve volume, the volume extracted between Vrel, and the volume at Pao = -25 cmH2O. Inflation pressure-volume (Pao-Vl) curves from Vrel were assessed for evidence of lung compression due to high Pl. Respiratory mechanics were measured during ventilation with a positive end-expiratory pressure of 0 and 7 cmH2O. Pneumoperitoneum stiffened the chest wall and the respiratory system (increased elastance), but did not stiffen the lung, and positive end-expiratory pressure reduced Ecw during pneumoperitoneum. Contrary to our expectations, pneumoperitoneum at Vrel did not significantly change Pes [8.7 (3.4) to 7.6 (3.2) cmH2O; means (SD)] or expiratory reserve volume [183 (142) to 155 (114) ml]. The inflation Pao-Vl curve above Vrel did not show evidence of increased lung compression with pneumoperitoneum. These results in predominantly obese subjects can be explained by the inspiratory effects of abdominal pressure on the rib cage.
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Affiliation(s)
- Stephen H Loring
- Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts;
| | - Negin Behazin
- Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | - Aileen Novero
- Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | - Victor Novack
- Soroka University Medical Center, Beer Sheva, Israel; and
| | - Stephanie B Jones
- Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | - Carl R O'Donnell
- Division of Pulmonary and Critical Care Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | - Daniel S Talmor
- Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
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Santos CL, Moraes L, Santos RS, dos Santos Samary C, Silva JD, Morales MM, Capelozzi VL, de Abreu MG, Schanaider A, Silva PL, Garcia CSNB, Pelosi P, Rocco PRM. The biological effects of higher and lower positive end-expiratory pressure in pulmonary and extrapulmonary acute lung injury with intra-abdominal hypertension. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2014; 18:R121. [PMID: 24928415 PMCID: PMC4095606 DOI: 10.1186/cc13920] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 05/27/2014] [Indexed: 01/01/2023]
Abstract
Introduction Mechanical ventilation with high positive end-expiratory pressure (PEEP) has been used in patients with acute respiratory distress syndrome (ARDS) and intra-abdominal hypertension (IAH), but the role of PEEP in minimizing lung injury remains controversial. We hypothesized that in the presence of acute lung injury (ALI) with IAH: 1) higher PEEP levels improve pulmonary morphofunction and minimize lung injury; and 2) the biological effects of higher PEEP are more effective in extrapulmonary (exp) than pulmonary (p) ALI. Methods In 48 adult male Wistar rats, ALIp and ALIexp were induced by Escherichia coli lipopolysaccharide intratracheally and intraperitoneally, respectively. After 24 hours, animals were anesthetized and mechanically ventilated (tidal volume of 6 mL/kg). IAH (15 mmHg) was induced and rats randomly assigned to PEEP of 5 (PEEP5), 7 (PEEP7) or 10 (PEEP10) cmH2O for 1 hour. Results In both ALIp and ALIexp, higher PEEP levels improved oxygenation. PEEP10 increased alveolar hyperinflation and epithelial cell damage compared to PEEP5, independent of ALI etiology. In ALIp, PEEP7 and PEEP10 increased lung elastance compared to PEEP5 (4.3 ± 0.7 and 4.3 ± 0.9 versus 3.1 ± 0.3 cmH2O/mL, respectively, P <0.01), without changes in alveolar collapse, interleukin-6, caspase-3, type III procollagen, receptor for advanced glycation end-products, and vascular cell adhesion molecule-1 expressions. Moreover, PEEP10 increased diaphragmatic injury compared to PEEP5. In ALIexp, PEEP7 decreased lung elastance and alveolar collapse compared to PEEP5 (2.3 ± 0.5 versus 3.6 ± 0.7 cmH2O/mL, P <0.02, and 27.2 (24.7 to 36.8) versus 44.2 (39.7 to 56.9)%, P <0.05, respectively), while PEEP7 and PEEP10 increased interleukin-6 and type III procollagen expressions, as well as type II epithelial cell damage compared to PEEP5. Conclusions In the current models of ALI with IAH, in contrast to our primary hypothesis, higher PEEP is more effective in ALIp than ALIexp as demonstrated by the activation of biological markers. Therefore, higher PEEP should be used cautiously in the presence of IAH and ALI, mainly in ALIexp.
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Monitoring of intratidal lung mechanics: a Graphical User Interface for a model-based decision support system for PEEP-titration in mechanical ventilation. J Clin Monit Comput 2014; 28:613-23. [PMID: 24549460 DOI: 10.1007/s10877-014-9562-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 02/03/2014] [Indexed: 10/25/2022]
Abstract
In mechanical ventilation, a careful setting of the ventilation parameters in accordance with the current individual state of the lung is crucial to minimize ventilator induced lung injury. Positive end-expiratory pressure (PEEP) has to be set to prevent collapse of the alveoli, however at the same time overdistension should be avoided. Classic approaches of analyzing static respiratory system mechanics fail in particular if lung injury already prevails. A new approach of analyzing dynamic respiratory system mechanics to set PEEP uses the intratidal, volume-dependent compliance which is believed to stay relatively constant during one breath only if neither atelectasis nor overdistension occurs. To test the success of this dynamic approach systematically at bedside or in an animal study, automation of the computing steps is necessary. A decision support system for optimizing PEEP in form of a Graphical User Interface (GUI) was targeted. Respiratory system mechanics were analyzed using the gliding SLICE method. The resulting shapes of the intratidal compliance-volume curve were classified into one of six categories, each associated with a PEEP-suggestion. The GUI should include a graphical representation of the results as well as a quality check to judge the reliability of the suggestion. The implementation of a user-friendly GUI was successfully realized. The agreement between modelled and measured pressure data [expressed as root-mean-square (RMS)] tested during the implementation phase with real respiratory data from two patient studies was below 0.2 mbar for data taken in volume controlled mode and below 0.4 mbar for data taken in pressure controlled mode except for two cases with RMS < 0.6 mbar. Visual inspections showed, that good and medium quality data could be reliably identified. The new GUI allows visualization of intratidal compliance-volume curves on a breath-by-breath basis. The automatic categorisation of curve shape into one of six shape-categories provides the rational decision-making model for PEEP-titration.
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Chalkias A, Xanthos T. Timing positive-pressure ventilation during chest compression: the key to improving the thoracic pump? EUROPEAN HEART JOURNAL-ACUTE CARDIOVASCULAR CARE 2013; 4:24-7. [DOI: 10.1177/2048872613516923] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Given the importance of increased coronary and cerebral perfusion pressure during cardiopulmonary resuscitation, the recommendation of limiting tidal volume and ventilation rate to 10 per minute in order not to inhibit venous return seems to be correct. However, although the resuscitation community believes that positive-pressure ventilation during cardiopulmonary resuscitation is bad for the circulation, proper timing of compression and ventilation may actually improve the circulation.
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Affiliation(s)
- Athanasios Chalkias
- National and Kapodistrian University of Athens, Medical School, MSc “Cardiopulmonary Resuscitation”, Athens, Greece
- Hellenic Society of Cardiopulmonary Resuscitation, Athens, Greece
| | - Theodoros Xanthos
- National and Kapodistrian University of Athens, Medical School, MSc “Cardiopulmonary Resuscitation”, Athens, Greece
- Hellenic Society of Cardiopulmonary Resuscitation, Athens, Greece
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Abstract
Abstract
Postoperative pulmonary complications are responsible for significant increases in hospital cost as well as patient morbidity and mortality; respiratory muscle dysfunction represents a contributing factor. Upper airway dilator muscles functionally resist the upper airway collapsing forces created by the respiratory pump muscles. Standard perioperative medications (anesthetics, sedatives, opioids, and neuromuscular blocking agents), interventions (patient positioning, mechanical ventilation, and surgical trauma), and diseases (lung hyperinflation, obesity, and obstructive sleep apnea) have differential effects on the respiratory muscle subgroups. These effects on the upper airway dilators and respiratory pump muscles impair their coordination and function and can result in respiratory failure. Perioperative management strategies can help decrease the incidence of postoperative respiratory muscle dysfunction. Such strategies include minimally invasive procedures rather than open surgery, early and optimal mobilizing of respiratory muscles while on mechanical ventilation, judicious use of respiratory depressant anesthetics and neuromuscular blocking agents, and noninvasive ventilation when possible.
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Rubini A, Monte DD, Catena V. Effects of the pneumoperitoneum and Trendelenburg position on respiratory mechanics in the rats by the end-inflation occlusion method. Ann Thorac Med 2012. [PMID: 23189096 PMCID: PMC3506099 DOI: 10.4103/1817-1737.102168] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
PURPOSE: To describe the consequences of the cranial displacement of the diaphgram occurring during pneumoperitoneum (Pnp) and/or Trendelenburg (Tnd) position on respiratory mechanics. Possible addictive effects and the changes of the viscoelastic respiratory system resistance were studied, which were not extensively described before. METHODS: The end-inflation occlusion method was applied on eight rats. It allows us to determine mechanical parameters such as respiratory system static elastance, the ohmic resistance due to frictional forces in the airways, and the additional viscoelastic impedance due to tissues deformation. Measurements during mechanical ventilation were taken in controls (supine position), after 20–25° head-down tilting (Tnd), after abdominal air insufflation up to 12 mmHg abdominal pressure in the supine position (Pnp), and combining Tnd + Pnp. Tnd and Pnp modalities were similar to those commonly applied during surgical procedures in humans. RESULTS: We confirmed the previously described detrimental effects on respiratory mechanics due to the diaphgram displacement during both Pnp and Tnd. The increment in the total resistive pressure dissipation was found to depend primarily on the effects on the viscoelastic characteristics of the respiratory system. Data suggesting greater effects of Pnp compared to those of Tnd were obtained. CONCLUSION: The cranial displacement of the diaphgram occurring as a consequence of Pnp and/or Tnd, for example during laparoscopic surgical procedures, causes an increment of respiratory system elastance and viscoelastic resistance. The analysis of addictive effects show that these are more likely to occur when Pnp + Tnd are compared to isolated Tnd rather than to isolated Pnp.
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Affiliation(s)
- Alessandro Rubini
- Department of Biomedical Sciences, University of Padova, Feltre (BL), Italy
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Abdominal compartment syndrome: a decade of progress. J Am Coll Surg 2012; 216:135-46. [PMID: 23062520 DOI: 10.1016/j.jamcollsurg.2012.09.004] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 08/26/2012] [Accepted: 09/10/2012] [Indexed: 12/22/2022]
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