Search

Both high tidal volume mechanical ventilation (HV) and hyperoxia (HO) have been implicated in ventilator-induced lung injury. However, patients with acute lung injury are often exposed to HO before the application of mechanical ventilation. The potential priming of the lungs for subsequent injury by exposure to HO has not been extensively studied. We provide evidence that HO (90%) for 12 h followed by HV (25 [micro]l/g) combined with HO for 2 or 4 h (HO-12h+HVHO-2h or -4h) induced severe lung injury in mice. Analysis of lung homogenates showed that lung injury was associated with cleavage of executioner caspases, caspases-3 and -7, and their downstream substrate poly(ADP-ribose) polymerase-1 (PARP-1). No significant lung injury or caspase cleavage was seen with either HO for 16 h or HV for up to 4 h. Ventilation for 4 h with HO (HVHO) did not cause significant lung injury without preexposure to HO. Twelve-hour HO followed by lower tidal volume (6 [micro]l/g) mechanical ventilation failed to produce significant injury or caspase cleavage. We also evaluated the initiator caspases, caspases-8 and -9, to determine whether the death receptor or mitochondrial-mediated pathways were involved. Caspase-9 cleavage was observed in HO-12h+HVHO-2h and -4h as well as HO for 16 h. Caspase-8 activation was observed only in HO-12h+HVHO-4h, indicating the involvement of both pathways. Immunohistochemistry and in vitro stretch studies showed caspase cleavage in alveolar epithelial cells. In conclusion, preexposure to HO followed by HV produced severe lung injury associated with alveolar epithelial cell apoptosis. mechanical ventilation; mouse doi: 10.1152/ajplung.00072.2010.

Byline: Fabio Ferrari (1,2), Qin Lu (1,2), Cassio Girardi (3), Olivier Petitjean (4), Charles-Hugo Marquette (5), Frederic Wallet (6), Jean-Jacques Rouby (1,2) Keywords: Nebulization; Ceftazidime; Pneumonia; Pseudomonas aeruginosa; Mechanical ventilation; Treatment Abstract: Purpose Ventilator-associated pneumonia caused by Pseudomonas aeruginosa with impaired sensitivity to ceftazidime is frequent in critically ill patients. The aim of the study was to compare lung tissue deposition and antibacterial efficiency between nebulized and intravenous administrations of ceftazidime in ventilated piglets with pneumonia caused by Pseudomonas aeruginosa with impaired sensitivity to ceftazidime. Methods Ceftazidime was administered 24 h following the intra-bronchial inoculation of Pseudomonas aeruginosa (minimum inhibitory concentration = 16 ug ml.sup.-1), either by nebulization (25 mg kg.sup.-1 every 3 h, n = 6) or by continuous intravenous infusion (90 mg kg.sup.-1 over 24 h after an initial rapid infusion of 30 mg kg.sup.-1, n = 6). Four non-treated inoculated animals served as controls. All piglets were killed 48 h (intravenous and control groups) or 51 h (aerosol group) after inoculation. Lung tissue concentrations and lung bacterial burden were assessed on multiple post-mortem sub-pleural lung specimens [(lower limit of quantitation = 10.sup.2 colony forming unit (cfu g.sup.-1)]. Results Ceftazidime trough lung tissue concentrations following nebulization were greater than steady-state lung tissue concentrations following continuous intravenous infusion [median and interquartile range, 24.8 (12.6--59.6) ug g.sup.-1 vs. 6.1 (4.6--10.8) ug g.sup.-1] (p < 0.001). After 24 h of ceftazidime administration, 83% of pulmonary segments had bacterial counts Conclusion Nebulized ceftazidime provides more efficient bacterial killing in ventilated piglets with pneumonia caused by Pseudomonas aeruginosa with impaired sensitivity to ceftazidime. Author Affiliation: (1) Reanimation Polyvalente Pierre Viars, Departement d'Anesthesie-Reanimation, UPMC Univ Paris 06, Hopital Pitie-Salpetriere, Assistance Publique-Hopitaux de Paris, 47-83 boulevard de l'Hopital, 75013, Paris, France (2) Polyvalent Intensive Care Unit Pierre Viars, La Pitie-Salpetriere Hospital, University Pierre et Marie Curie, Paris, France (3) Department of Anesthesiology, Federal University of Sao Paulo, Escola Paulista de Medicina, Sao Paulo, Brazil (4) Department of Pharmacology, Avicenne Hospital, Bobigny, France (5) DHURE and INSERM U 416, University of Medicine, Lille, France (6) Department of Bacteriology, University of Medicine, Lille, France Article History: Registration Date: 17/07/2009 Received Date: 03/03/2009 Accepted Date: 08/07/2009 Online Date: 04/08/2009

Byline: Javier Hortal (1), Maddalena Giannella (2), Maria Jesus Perez (1), Jose Maria Barrio (1), Manuel Desco (3), Emilio Bouza (2,4), Patricia Munoz (2,4) Keywords: Ventilator-associated pneumonia; Heart surgery; Nosocomial infection; Nosocomial pneumonia; Risk factors for ICU nosocomial infection Abstract: Purpose Major heart surgery (MHS) patients are a particularly high-risk population for nosocomial infections. Our objective was to identify risk factors for ventilator-associated pneumonia (VAP) in patients undergoing MHS. Methods Prospective study including 1,844 patients operated from 2003 to 2006. Results Overall 106 patients (140 episodes) developed one or more episodes of VAP (5.7%, 22.2 episodes per 1,000 days of mechanical ventilation). VAP incidence was 45.9% in those patients requiring more than 48 h of MV. Enterobacteriaceae (32.8), Pseudomonas aeruginosa (28.6%) and Staphylococcus aureus (27.1%, of which 65.8% were methicillin resistant) were the principal microorganisms causing VAP. The independent risk factors for VAP were: age >70, perioperative transfusions, days of mechanical ventilation, reintubation, previous cardiac surgery, emergent surgery and intraoperative inotropic support. Median length of stay in the ICU for patients who developed VAP or not was, respectively, 25.5 versus 3 days (P < 0.001), and mortality was, respectively, 45.7 versus 2.8% in both populations (P < 0.001). We developed a predictive preoperative score with a sensitivity of 93% and a specificity of 40%. Conclusions VAP is common in patients undergoing MHS that require more than 48 h of MV. In that 'high-risk' population, innovative preventive measures should be developed and applied. Author Affiliation: (1) Department of Anesthesia, Hospital General Universitario Gregorio Maranon, Madrid, Spain (2) Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Maranon, Madrid, Spain (3) Department of Experimental Medicine, Hospital General Universitario Gregorio Maranon, Doctor Esquerdo 46, 28007, Madrid, Spain (4) CIBER de Enfermedades Respiratorias (CIBERES), Barcelona, Spain Article History: Registration Date: 28/05/2009 Received Date: 14/09/2008 Accepted Date: 06/03/2009 Online Date: 26/06/2009 Article note: This article is discussed in the editorial available at: doi: 10.1007/s00134-009-1522-4.

Byline: Leticia Martinez-Caro (1), Jose A. Lorente (1), Judith Marin-Corral (1,2), Carolina Sanchez-Rodriguez (1), Alberto Sanchez-Ferrer (1), Nicolas Nin (1), Antonio Ferruelo (1), Marta Paula (1), Pilar Fernandez-Segoviano (1), Esther Barreiro (1,2), Andres Esteban (1) Keywords: Mechanical ventilation; Tidal volume; Lung injury; Vascular dysfunction; Oxygen reactive species; Nitrogen reactive species Abstract: Objective To demonstrate that increased formation of reactive oxygen (ROS) and nitrogen species (RNS) is involved in VILI-induced vascular dysfunction. Methods Male Sprague-Dawley anesthetized rats were ventilated for 60 min using low V.sub.T ventilation [V.sub.T 9 ml/kg, positive end-expiratory pressure (PEEP) 5 cm[H.sub.2]O, n = 18], and high V.sub.T ventilation (V.sub.T 35 ml/kg, zero PEEP, n = 18). Arterial pressure and respiratory system mechanics were monitored. Blood samples for the determination of arterial blood gases and lactate concentration were drawn. Vascular rings from the thoracic aortae were mounted in organ baths for isometric tension recording. We studied endothelium-dependent relaxation in norepinephrine-precontracted rings (acetylcholine, 10 nM--10 uM) and contraction induced by norepinephrine (1 nM--10 uM) in resting vessels. Vascular rings were preincubated for 30 min with Zn--Mn--SOD (100 u/ml) or tempol (10.sup.-4 M) (extracellular and intracellular superoxide scavengers, respectively) or MnTMPyP (10.sup.-5 M) (a superoxide and peroxynitrite scavenger). The presence of superoxide and nitrotyrosine in aortic rings was evaluated by immunofluorescence. Results High V.sub.T ventilation induced hypotension, systemic acidosis, hypoxemia and hyperlactatemia, as well as impairment in acetylcholine and norepinephrine-induced responses in vitro. Responses to acetylcholine were improved by tempol (P = 0.004) and completely corrected (P < 0.001) by MnTMPyP. Responses to norepinephrine were also improved by treatment with tempol (P < 0.001) and MnTMPyP (P < 0.001). However, Zn--Mn--SOD did not improve acetylcholine- or norepinephrine-induced responses. Immunostaining for both superoxide and nitrotyrosine was increased in aortic rings from the high V.sub.T group. Conclusions Our data support a role for intracellular ROS and peroxynitrite in the high V.sub.T ventilation-induced vascular dysfunction. Author Affiliation: (1) Centro de Investigacion en Red de Enfermedades Respiratorias (CibeRes), Hospital Universitario de Getafe, Universidad Europea de Madrid, Carretera de Toledo, km 12.500, Getafe, 28905, Madrid, Spain (2) Pulmonology Department-URMAR, IMIM-Hospital del Mar, CIBERES, CEXS, Universitat Pompeu Fabra (UPF), PRBB, C/Dr. Aiguader, 88, 08003, Barcelona, Spain Article History: Registration Date: 23/03/2009 Received Date: 10/09/2008 Accepted Date: 17/03/2009 Online Date: 10/04/2009 Article note: Electronic supplementary material The online version of this article (doi: 10.1007/s00134-009-1469-5) contains supplementary material, which is available to authorized users.

Byline: Rafael Fernandez (1), Francisco Baigorri (1), Antonio Artigas (1) Keywords: Noninvasive ventilation; Ethics; Do-not-intubate orders; Hospital mortality; Chronic obstructive pulmonary disease Abstract: Objective Randomized clinical trials demonstrating benefits of noninvasive ventilation (NIV) systematically exclude patients with 'do-not-intubate' (DNI) orders, but in daily clinical practice these patients are frequently treated with NIV. A recent North American study found a 43% hospital survival rate in patients with DNI orders. Our hypothesis was that, due to the very different social and cultural setting, written DNI orders in a southern European country would be restricted to a population with a poor outcome, independently of whether they receive NIV, and we analyzed hospital survival in patients receiving NIV and the impact of DNI orders on survival. Design and setting Retrospective cohort study in a general ICU in a university-affiliated hospital. Patients and methods All 233 patients treated with NIV during 2002--2004. We recorded clinical characteristics on admission, mortality risk by APACHE II and ICU and hospital outcome, and 6-month outcome. Results Hospital survival was 66%. Survival was better in the 199 patients without DNI orders than in the 36 with DNI orders both during hospitalization (74% vs. 26%, OR 7.9) and after 6 months (64% vs. 15%, OR 10.2). In both groups the presence of COPD was associated with better prognosis during hospitalization, but not in the medium-term. Conclusion Our study suggests that NIV offers low expectations for medium-term survival in DNI patients. Author Affiliation: (1) Critical Care Center, Hospital de Sabadell, Parc Tauli s/n, 08208, Sabadell, Spain Article History: Registration Date: 28/09/2006 Received Date: 16/05/2006 Accepted Date: 22/09/2006 Online Date: 09/11/2006 Article note: Financial support was provided by the 'Red Gira' Network of Excellence in Acute Respiratory Failure.

Byline: M. C. Boque (1), B. Gualis (1), A. Sandiumenge (1), J. Rello (1) Keywords: Endotracheal tube obstruction; Reflectometry Abstract: Objective To quantify the incidence and degree of endotracheal tube intraluminal obstruction after mechanical ventilation and its relation to time of intubation. Design Prospective observational study. Setting A 14-bed medical-surgical intensive care unit at a university-affiliated teaching hospital. Patients Ninety-four endotracheal tubes used in 80 patients requiring mechanical ventilation for more than 12 h. Interventions and results Acoustic reflectometry was performed in every endotracheal tube after patient extubation to measure its volume reduction. The intraluminal volumes of used endotracheal tubes in mechanically ventilated patients were significantly lower than those of unused tubes of the same size (5.52+-0.92 ml.sup.3 versus 6.54+-0.79 ml.sup.3, p Conclusions Inadvertent endotracheal tube obstruction was common in patients requiring mechanical ventilation and may be significant as early as at 24 h. Moderate obstruction in endotracheal tube lumens should be suspected in cases of difficulties in weaning, even in patients who were ventilated for less than 1 day. Author Affiliation: (1) University Hospital Joan XXIII, University Rovira i Virgili, Mallafre Guasch 4, 43007, Tarragona, Spain Article History: Registration Date: 09/09/2004 Received Date: 26/09/2003 Accepted Date: 07/09/2004 Online Date: 02/10/2004 Article note: Presented, in part, at the 16th European Society Intensive Care Medicine Congress, Amsterdam, October 2003.

Byline: Ulrich Zwiener (1), Bernd Walter (1), Barbara Kratzsch (1), Reinhard Bauer (1) Keywords: Regional cerebral blood flow; Artificial ventilation; Spontaneous respiration; Normoxia; Normocapnic hypoxia; Newborn piglets Abstract: Objective To estimate the effect of artificial ventilation on regional cerebral blood flow, cardiovascular regulation, and cerebral oxidative metabolism in newborns. Design and subjects Comparison of three randomized treatment groups of newborn piglets: Group 1 (artificially ventilated sham-operated group n =7) group 2 (artificially ventilated group with normoxia and moderate normocapnic hypoxia n =7) group 3 (spontaneously breathing group with normoxia and moderate normocapnic hypoxia n =6). Measurements and results Animals were anesthetized with 0.5% isoflurane in 70% nitrous oxide and 30% oxygen. Groups 1 and 2 were artificially ventilated. Animals in group 3 breathed spontaneously. Moderate normocapnic hypoxia was induced in groups 2 and 3 for 1 h by lowering the inspiratory oxygen fraction from 0.35 to 0.11. Mode of ventilation induced at most marginal effects on global cerebrovascular response, cardiovascular regulation, and cerebral oxidative metabolism. However, under normoxic conditions, regional cerebral blood flow of the medulla oblongata, pons, mesencephalon, thalamus, and cerebellum were markedly reduced in artificially ventilated piglets (P Conclusion Artificial ventilation clearly induces reduced neuronal activity in the brain stem and cerebellum of newborn piglets. This is suggested by a considerably reduced blood flow in these regions under normoxia and moderate normocapnic hypoxia. However, there is no relevant detrimental effect on cardiovascular regulation and brain oxidative metabolism. Author Affiliation: (1) Institute of Pathophysiology, Friedrich Schiller University, 07740 , Jena, Germany Article History: Received Date: 31/01/2002 Accepted Date: 15/08/2003 Online Date: 16/10/2003 Article note: Supported by Bundesministerium fur Forschung und Technologie grant 01ZZ9104

Byline: Rene Robert (1), Ghislaine Grollier (2), Jean-Pierre Frat (1), Cendrine Godet (1), Michele Adoun (1), Jean-Louis Fauchere (2), Pierre Dore (1) Keywords: Anaerobic bacteria; Lower respiratory tract colonization; Mechanical ventilation Abstract: Objective To study lower respiratory tract colonization by anaerobic bacteria in ICU patients on prolonged mechanical ventilation using two types of protected tracheal sampling methods. Design and setting Prospective clinical investigation in the intensive care unit of a university hospital. Patients Twenty-six consecutive patients mechanically ventilated within 24 h after their admission in ICU and with expected duration of mechanical ventilation longer than 7 days. Measurements and results Two types of protected tracheal sampling methods were obtained without the use of bronchoscopic guidance on the day following intubation and twice a week until extubation: protected tracheal aspiration and protected tracheal specimen brush. Specific methods for anaerobic isolation were used. Early colonization was defined if colonization occurred within the first 5 days after intubation. Of the 26 patients studied 22 were colonized by at least one bacterial strain. Twenty-one patients were colonized by aerobic and 15 by anaerobic bacteria. Twenty-eight anaerobic strains were identified, with bacterial counts higher than 10.sup.3 cfu/ml in 11 cases. Of the 15 patients colonized by anaerobes 14 were also colonized by aerobic bacteria. The use of protected specimens ruled out oropharyngeal contamination. Early onset colonization occurred in 16 of 22 patients colonized by aerobes and in 8 of 15 patients colonized by anaerobes. Five patients developed ventilatory-acquired pneumonia following colonization (by anaerobic bacteria in two cases). In eight patients colonization by anaerobic bacteria occurred despite antimicrobial therapy. Conclusions These results show that anaerobic bacteria frequently colonize the lower respiratory tract of mechanically ventilated patients and underline the potential importance of the anaerobic bacteria in ventilatory acquired pneumonia. Author Affiliation: (1) Service de Reanimation Medicale, Hopital Jean Bernard CHU, 86021, Poitiers cedex, France (2) Laboratoire de Microbiologie A, Hopital Jean Bernard CHU, 86021, Poitiers cedex, France Article History: Received Date: 07/08/2002 Accepted Date: 21/02/2003 Online Date: 16/04/2003 Article note: An editorial regarding this article can be found in the same issue ( http://dx.doi.org/10.1007/s00134-003-1795-y) An erratum to this article can be found at http://dx.doi.org/10.1007/s00134-003-1994-6

Byline: Stephen E. Lapinsky (1), Laura Hawryluck (2) Keywords: Severe acute respiratory syndrome Acute respiratory distress syndrome Mechanical ventilation Infection control Abstract: Background. Severe acute respiratory syndrome (SARS) is a contagious viral illness first recognized in late 2002. It has now been documented in 26 countries worldwide, with significant outbreaks in China, Hong Kong, Singapore, and Toronto. Research into identifying the etiological agent, evaluating modes of disease transmission, and treatment options is currently ongoing. Discussion. The disease can produce a severe bilateral pneumonia, with progressive hypoxemia. Up to 20% of patients require mechanical ventilatory support, with a fatal outcome occurring in about 5% of cases. Conclusions. We review the current knowledge about this disease, with particular emphasis on ICU management and infection control precautions to prevent disease transmission. Author Affiliation: (1) Mount Sinai Hospital, Interdepartmental Division of Critical Care, University of Toronto, 600 University Ave, M5G 1X5, Toronto, Canada (2) University Health Network, Interdepartmental Division of Critical Care, University of Toronto, 500 University Ave, M5G 1X7, Toronto, Canada Article History: Received Date: 23/04/2003 Accepted Date: 25/04/2003 Article note: Electronic Publication

Byline: Johannes P. van de Leur (1), Jan H. Zwaveling (2), Bert G. Loef (3), Cees P. van der Schans (1) Keywords: Airway suctioning Mechanical ventilation Complications Costs Abstract: Study objective.. Endotracheal suctioning in intubated patients is routinely applied in most ICUs but may have negative side effects. We hypothesised that on-demand minimally invasive suctioning would have fewer side effects than routine deep endotracheal suctioning, and would be comparable in duration of intubation, length of stay in the ICU, and ICU mortality. Design.. Randomised prospective clinical trial. Setting.. In two ICUs at University Hospital Groningen, the Netherlands. Patients.. Three hundred and eighty-three patients requiring endotracheal intubation for more than 24 h. Interventions.. Routine endotracheal suctioning (n=197) using a 49-cm suction catheter was compared with on-demand minimally invasive airway suctioning (n=186) using a suction catheter only 29 cm long. Measurements and results.. No differences were found between the routine endotracheal suctioning group and the minimally invasive airway suctioning group in duration of intubation [median (range) 4 (1--75) versus 5 (1--101) days], ICU-stay [median (range) 8 (1--133) versus 7 (1--221) days], ICU mortality (15% versus 17%), and incidence of pulmonary infections (14% versus13%). Suction-related adverse events occurred more frequently with RES interventions than with MIAS interventions decreased saturation: 2.7% versus 2.0% (P=0.010) increased systolic blood pressure 24.5% versus 16.8% (P Conclusions.. This study demonstrated that minimally invasive airway suctioning in intubated ICU-patients had fewer side effects than routine deep endotracheal suctioning, without being inferior in terms of duration on intubation, length of stay, and mortality. Author Affiliation: (1) Centre for Rehabilitation, University Hospital Groningen, PO Box 30.001, 9700 RB, Groningen, The Netherlands (2) Dept. of General Surgery and Intensive Care, University Hospital Groningen, Groningen, The Netherlands (3) Dept. Cardio-Thoracic Surgery and Intensive Care, University Hospital Groningen, Groningen, The Netherlands (4) University for Professional Education, Hanzehogeschool and Centre for Rehabilitation, University Hospital Groningen, Groningen, The Netherlands Article History: Received Date: 04/12/2001 Accepted Date: 10/12/2002 Article note: Electronic Publication

Byline: Cesare Gregoretti (1), Marco Confalonieri (2), Paolo Navalesi (3), Vincenzo Squadrone (4), Pamela Frigerio (5), Fabio Beltrame (2), Giorgio Carbone (6), Giorgio Conti (7), Federica Gamna (4), Stefano Nava (3), Edoardo Calderini (8), Yoanna Skrobik (9), Massimo Antonelli (7) Keywords: Non-invasive mask ventilation Face mask Patient comfort Skin breakdown Eye irritation Abstract: Objective: To evaluate patient comfort, skin breakdown and eye irritation when comparing a prototype face mask (PM) and conventional face masks (CMs) during non-invasive ventilation. Setting and design: Eight centers (intensive or intermediate care units). Multicenter randomized study. Populations: Patients with acute respiratory failure of different etiologies. Interventions: Patients were randomized to CMs or PM when ventilation was expected to last at least 12 consecutive hours a day for two consecutive days. Patient comfort, skin breakdown and eye irritation, assessed by means of standardized scoring systems, were measured after 24 and 48 h and before discontinuing ventilation. Results: Hundred ninety-four patients were randomized. Forty-seven patients were finally enrolled: PM (24) and CMs (23). Ventilator settings were similar in the two groups at the beginning of the treatment and after 24 and 48 h. Skin breakdown was significantly higher in the CMs group over the study period (p Author Affiliation: (1) Intensive Care Unit, Azienda Ospedaliera CTO-CRF-ICORMA, Via Zuretti 29, 10100 Turin, Italy (2) Pulmonary Unit and ARTA Institute, Azienda Ospedaliera di Trieste, S.da di Fiume 447, 34100 Trieste, Italy (3) Fondazione Salvatore Maugeri, Via Ferrata, 27100 Pavia, Italy (4) Intensive Care Unit and Medical Rehabilitation Department, S. Luigi Hospital, Orbassano, 10100 Turin, Italy (5) Niguarda Hospital, Pza OspedaleMaggiore 2, 20100 Milan, Italy (6) Emergency Department Gradenigo Hospital, C.so Regina Margherita 8/10, 10153 Turin, Italy (7) Anesthesia and Intensive Care Institute, Universita Cattolica del Sacro Cuore, Largo Gemelli 1, 00168 Rome, Italy (8) Intensive Care Unit, ICP, Clinica De Marchi, Via della Commenda 9, 20132 Milan, Italy (9) Critical Care Division, Maisonneuve Rosemont Hospital, 5415 boul de l'Assomption, Quebec HIT 2M4, Canada Article History: Received Date: 07/03/2001 Accepted Date: 22/11/2001 Article note: Electronic Publication

Byline: Frederic Adnet (1), Ghislain Dhissi (1), Stephen W. Borron (2), Michel Galinski (3), Fatima Rayeh (4), Michel Cupa (1), Jean Pourriat (5), Frederic Lapostolle (1) Keywords: Paralysis Morbidity Mortality Mechanical ventilation Near fatal asthma Abstract: Objective: To assess the characteristics and the incidence of morbidity of intubated asthmatic patients who received long-term paralysis. Design: Retrospective cohort study. Setting: Five intensive care units (ICUs) in Paris and the surrounding suburbs. Patients and participants: The NMB group consisted of patients who received neuromuscular blocking agents for more than 12 h (NMB group) versus sedation alone (SED). Interventions: None. Measurements and results: The incidence of post-extubation muscle weakness and/or myopathy was 18% in the NMB group compared to 2% in the SED group (p=0.01). The occurrence of ventilator-associated pneumonia was higher in the NMB group (42% versus 4% p Author Affiliation: (1) SAMU 93, Hopital Avicenne, Universite Paris XIII, 93009 Bobigny Cedex, France (2) Department of Emergency Medicine, George Washington University Hospital, Washington DC 20037, USA (3) Service d'Anesthesie-Reanimation, Hopital Ambroise Pare, 92130 Boulogne Billancourt, France (4) Service de Reanimation, Hopital de Poitiers, 86021 Poitiers Cedex, France (5) Service de Reanimation, Hopital Jean Verdier, 93140 Bondy, France Article History: Received Date: 08/12/2000 Accepted Date: 03/09/2001 Article note: Final revision received: 23 August 2001 Electronic Publication

Byline: P. Kiefer (1), A. Morin (1), C. Putzke (1), H. Wiedeck (1), M. Georgieff (1), P. Radermacher (1) Keywords: Intragastric pressure Mechanical ventilation PCO2 gradients Prone position Abstract: Objective: To evaluate the effects of mechanical ventilation in the prone position on gastric mucosal-arterial PCO.sub.2 gradients. Design: Prospective clinical study. Setting: Intensive care unit in a university clinic. Patients: Twenty-five patients requiring mechanical ventilation. The physician in charge indicated the turning manoeuver for the individual patient. Measurements/results: In addition to routine measurements of global hemodynamics and gas exchange we determined: 1) intragastric pressure and 2) gastric mucosal-arterial PCO.sub.2 difference. After a baseline measurement in the supine position patients were turned to the prone position. After 60', 120', a median of 6.5 h (2--10 h) in the prone position, and again after 60' in the supine position, all measurements were repeated. Global hemodynamics remained unaltered throughout the study. While gastric mucosal-arterial PCO.sub.2 gradients did not change significantly during the first 60 min in the prone position, they significantly increased during the following 60 min [median/percentile: baseline: 6 (1 to --3) 60': 7 (15--5) 120': 13 (20--8) mmHg]. The median intragastric pressure was not significantly affected [baseline: 10 (13--5) 60': 12 (16--8) 120': 11 (13--7) mmHg], but 9 of the 11 patients in whom intragastric pressure increased during the first 60 min in the prone position also showed significantly increased PCO.sub.2 gradients (P Author Affiliation: (1) Universitat Ulm, Universitatsklinik fur Anasthesiologie, Prittwitzstrasse 43, 89075 Ulm (Donau), Germany Article History: Received Date: 21/09/2000 Accepted Date: 08/05/2001 Article note: Final revision received: 7 March 2001 Electronic Publication

Byline: A. Chishti (1), A. M. Batchelor (1), R. E. Bullock (1), B. Fulton (1), A. D. Gascoigne (1), S. V. Baudouin (1) Keywords: Key words Outcomes; Hypoxaemia; Sleep-related breathing disorders; Obstructive sleep apnoea; Central sleep apnoea; Mechanical ventilation; Complications; Intensive care Abstract: Objectives: To determine the incidence of sleep-related breathing disorders and nocturnal hypoxaemia in patients discharged from ICU following prolonged mechanical ventilation.APDesign: Prospective, consecutive patient observational study.APSetting: The medical and surgical wards of a University Hospital.APPatients and participants: Fifteen consecutive, adult patients discharged from the ICU who had received more than 48 h of mechanical ventilation were studied. Ten healthy volunteers acted as controls.APMeasurements and results: Overnight, multi-channel pneumographic studies were performed on all patients and controls. Chest and abdominal wall movement, air flow, oxygen saturation and snoring were continuously recorded. Data was analysed by both visual inspection of the traces and by computer-based algorithms. An apnoea/hypopnoea index was calculated for each patient and volunteer. Volunteers had an apnoea/hypopnoea index of less than 5 and had no episodes of nocturnal oxygen desaturation (SaO.sub.2 < 90 %). Despite oxygen therapy 13/15 patients had episodes of desaturation and 9/15 spent more than 2 h with an SaO.sub.2 < 90 %. Eleven patients had an abnormal apnoea/hypopnoea index (range 5--34 events/h). Four patients had predominantly obstructive events while 7 primarily had hypopnoeas.APConclusions: Significant overnight oxygen desaturation is common in patients discharged from ICU who have received prolonged mechanical ventilation. This group also has a significant incidence of sleep-related breathing disorders and this mechanism is likely to be important in the pathogenesis of the hypoxaemia. Author Affiliation: (1) Department of Anaesthesia and Intensive Care, Royal Victoria Infirmary, Newcastle upon Tyne, NE1 4LP, United Kingdom e-mail: s. v.bauduin@ncl.ac.uk Tel.: + 44-1 91-2 22 66 68 Fax: 44-1 91-2 22 89 88, GB Article note: Revision: 2 August 1999/Final revision received: 15 December 1999/Accepted: 12 January 2000

Byline: P. G. Flanagan (1), G. P. Findlay (3), J. T. Magee (2), A. Ionescu (4), R. A. Barnes (1), M. Smithies (3) Keywords: Key words Ventilator-associated pneumonia; Non-bronchoscopic lung lavage; Quantitative culture; Bacterial index Abstract: Objectives: (1)To assess the diagnostic utility of quantitative cultures of non-bronchoscopic lung lavage (NBL) in ventilator-associated pneumonia and evaluate the role of the Bacterial Index (2) To assess the predictive value of NBL surveillance quantitative cultures in ventilated patients (3) To evaluate the Clinical Pulmonary Infection Score (CPIS) system in ventilated patients.APDesign: A prospective comparison of NBL with bronchoscopic bronchoalveolar lavage and protected specimen brush.APSetting: Three intensive care units in academic tertiary care centres.APPatients: 145 adults ventilated for 72 h, with and without clinical signs of pneumonia.APInterventions: Sampling of lower airway secretions by NBL, bronchoalveolar lavage and protected specimen brush.APMain outcome measures: Diagnostic reliability of quantitative cultures, Bacterial Index and CPIS.APResults: 34 episodes of clinical ventilator-associated pneumonia were documented in 32 patients. 9 episodes were confirmed by concordant blood/pleural culture or post-mortem lung examination. Qualitative concordance of the predominant pathogen between sequential NBL: bronchoalveolar lavage and protected specimen brush was 83 %. Sensitivity and specificity of non-directed bronchial lavage at a threshold of 10.sup.4 CFU/ml were 68 % and 70 % respectively (p = 0.003) and were comparable with the bronchoscopic methods. However, the low positive predictive value of NBL indicates that quantitation in the absence of clinical signs is unlikely to be useful. Bacterial Index did not improve discriminatory power of quantitation compared with bacterial load of predominant organism. Mean CPIS for confirmed pneumonia cases was 8.4 +- 1.01, significantly higher than for non-pneumonia observations (p = < 0.0001).APConclusion: NBL is a simple, safe, cheap, readily-available method of diagnosing ventilator-associated pneumonia with comparable diagnostic accuracy to bronchoscopic techniques. Quantitation of respiratory tract cultures can exclude pneumonia in patients with equivocal clinical signs. The diagnostic threshold should vary depending on the length of ventilation, likelihood of pneumonia and antibiotic administration. The Bacterial Index is a flawed mathematical device that has no contributory role in pneumonia diagnosis. The CPIS has some diagnostic role in selected cohorts of ventilated patients. Author Affiliation: (1) Department of Medical Microbiology, University of Wales College of Medicine, Cardiff, Wales, CF4 4XN, UK e-mail: flanaganpg@cf.ac.uk Tel.: + 44-12 22-74 65 80 Fax: + 44-12 22-74 41 23, GB (2) Department of Medical Microbiology, Cardiff Public Health Laboratory, University Hospital of Wales, Cardiff, CF4 4XW, UK, GB (3) Intensive Care Unit, University Hospital of Wales, Cardiff, Wales, CF4 4XW, UK, GB (4) Department of Respiratory Medicine, Llandough Hospital, Penarth, Wales, UK, GB Article note: Received: 23 March 1999 Final revision received: 5 November 1999 Accepted: 15 November 1999

Byline: C. D. Punt (1), J. J. Schreuder (2), J. R. C. Jansen (3), S. A. A. P. Hoeksel (2), A. Versprille (3) Keywords: Key words (Best) PEEP; Haemodynamics; Oxygen transport; Pulmonary edema Abstract: Objective: The aim of this study was to show the feasibility of a slow, continuously increasing level of positive end-expiratory pressure (PEEP) (ramp manoeuvre) in selecting best PEEP and to evaluate whether best PEEP, as definded by maximal oxygen transport, coincides with best systemic arterial oxygenation or best compliance. Design: In 11 anaesthetized piglets, PEEP was increased between 0 cm[H.sub.2]O (zero end-expiratory pressure ZEEP) and 15 cm[H.sub.2]O (PEEP.sub.15) with a constant rate of 0.67 cm[H.sub.2]O * min.sup.-1. This ramp manoeuvre was performed both under normal conditions and after induction of an experimental lung oedema. During the ramp manoeuvre, haemodynamic and pulmonary variables were monitored almost continuously. Results: During the rise in PEEP, cardiac output declined in a non-linear way. In the series with normal conditions, best PEEP was always found at ZEEP. In the series with experimental lung oedema, best PEEP, as defined by maximum oxygen transport, was found at PEEP.sub.1--6, as defined by maximal compliance, at PEEP.sub.7.5 and by maximal arterial oxygen tension (PaO.sub.2) at PEEP.sub.10--14. Conclusions: Best PEEP according to oxygen transport is lower than best PEEP according to compliance and PaO.sub.2 the use of PEEP as a ramp might prevent unnecessarily high levels of PEEP. Author Affiliation: (1) Atrium Medisch Centrum, Department of Anaesthesiology, P. O. Box 4446, 6401 CX Heerlen, The Netherlands Tel.: + 31 (45) 5 76 70 10 Fax: + 31 (45) 5 76 60 55, NL (2) Department of Anaesthesiology, Cardiovascular Research Institute, University Hospital Maastricht, The Netherlands, NL (3) Pathophysiological Laboratory of the Department of Pulmonary Diseases, Erasmus University Rotterdam, The Netherlands, NL Article note: Received: 16 June 1997 Accepted: 24 April 1998

Byline: J. W. Christman (1), T. S. Blackwell (1) Author Affiliation: (1) Division of Allergy, Pulmonary and Critical Care Medicine, Center for Lung Research, Vanderbilt University, Nashville, TN 37232-2650, USA Tel.: + 1 6 15 3 22 34 12 Fax: + 1 6 15 3 43 74 48 email: john.christman@mcmail.vanderbilt., US Article note: Received: 29 May 1998 Accepted: 12 June 1998