Jean-Marie Sainty

Comparison of prone positioning and high-frequency oscillatory ventilation in patients with acute respiratory distress syndrome*

Objective:Both prone position and high-frequency oscillatory ventilation (HFOV) have the potential to facilitate lung recruitment, and their combined use could thus be synergetic on gas exchange. Keeping the lung open could also potentially be lung protective. The aim of this study was to compare physiologic and proinflammatory effects of HFOV, prone positioning, or their combination in severe acute respiratory distress syndrome (ARDS). Design:Prospective, comparative randomized study. Setting:A medical intensive care unit. Patients:Thirty-nine ARDS patients with a Pao2/Fio2 ratio <150 mm Hg at positive end-expiratory pressure ≥5 cm H2O. Interventions:After 12 hrs on conventional lung-protective mechanical ventilation (tidal volume 6 mL/kg of ideal body weight, plateau pressure not exceeding the upper inflection point, and a maximum of 35 cm H2O; supine-CV), 39 patients were randomized to receive one of the following 12-hr periods: conventional lung-protective mechanical ventilation in prone position (prone-CV), HFOV in supine position (supine-HFOV), or HFOV in prone position (prone-HFOV). Measurements and Main Results:Prone-CV (from 138 ± 58 mm Hg to 217 ± 110 mm Hg, p < .0001) and prone-HFOV (from 126 ± 40 mm Hg to 227 ± 64 mm Hg, p < 0.0001) improved the Pao2/Fio2 ratio whereas supine-HFOV did not alter the Pao2/Fio2 ratio (from 134 ± 57 mm Hg to 138 ± 48 mm Hg). The oxygenation index ({mean airway pressure × Fio2 × 100}/Pao2) decreased in the prone-CV and prone-HFOV groups and was lower than in the supine-HFOV group. Interleukin-8 increased significantly in the bronchoalveolar lavage fluid (BALF) in supine-HFOV and prone-HFOV groups compared with prone-CV and supine-CV. Neutrophil counts were higher in the supine-HFOV group than in the prone-CV group. Conclusions:Although HFOV in the supine position does not improve oxygenation or lung inflammation, the prone position increases oxygenation and reduces lung inflammation in ARDS patients. Prone-HFOV produced similar improvement in oxygenation like prone-CV but was associated with higher BALF indexes of inflammation. In contrast, supine-HFOV did not improve gas exchange and was associated with enhanced lung inflammation.

Prone position and positive end-expiratory pressure in acute respiratory distress syndrome*

ObjectiveTo determine whether positive end-expiratory pressure (PEEP) and prone position present a synergistic effect on oxygenation and if the effect of PEEP is related to computed tomography scan lung characteristic. DesignProspective randomized study. SettingFrench medical intensive care unit. PatientsTwenty-five patients with acute respiratory distress syndrome. InterventionsAfter a computed tomography scan was obtained, measurements were performed in all patients at four different PEEP levels (0, 5, 10, and 15 cm H2O) applied in random order in both supine and prone positions. Measurements and Main ResultsAnalysis of variance showed that PEEP (p < .001) and prone position (p < .001) improved oxygenation, whereas the type of infiltrates did not influence oxygenation. PEEP and prone position presented an additive effect on oxygenation. Patients presenting diffuse infiltrates exhibited an increase of Pao2/Fio2 related to PEEP whatever the position, whereas patients presenting localized infiltrates did not have improved oxygenation status when PEEP was increased in both positions. Prone position (p < .001) and PEEP (p < .001) reduced the true pulmonary shunt. Analysis of variance showed that prone position (p < .001) and PEEP (p < .001) reduced the true pulmonary shunt. The decrease of the shunt related to PEEP was more pronounced in patients presenting diffuse infiltrates. A lower inflection point was identified in 22 patients (88%) in both supine and prone positions. There was no difference in mean lower inflection point value between the supine and the prone positions (8.8 ± 2.7 cm H2O vs. 8.4 ± 3.4 cm H2O, respectively). ConclusionsPEEP and prone positioning present additive effects. The prone position, not PEEP, improves oxygenation in patients with acute respiratory distress syndrome with localized infiltrates.

Influence of support on intra-abdominal pressure, hepatic kinetics of indocyanine green and extravascular lung water during prone positioning in patients with ARDS: a randomized crossover study

IntroductionProne positioning (PP) on an air-cushioned mattress is associated with a limited increase in intra-abdominal pressure (IAP) and an absence of organ dysfunction. The respective influence of posture by itself and the type of mattress on these limited modifications during the PP procedure remains unclear. The aim of this study was to evaluate whether the type of support modifies IAP, extravascular lung water (EVLW) and the plasma disappearance rate of indocyanine green (PDRICG) during PP.MethodsA prospective, randomized, crossover study of 20 patients with acute respiratory distress syndrome (ARDS) was conducted in a medical intensive care unit in a teaching hospital. Measurements were made at baseline and repeated after 1 and 6 hours of two randomized periods of 6 hours of PP with one of two support types: conventional foam mattress or air-cushioned mattress.ResultsAfter logarithmic transformation of the data, an analysis of variance (ANOVA) showed that IAP and PDRICG were significantly influenced by the type of support during PP with an increase in IAP (P < 0.05 by ANOVA) and a decrease in PDRICG on the foam mattress (P < 0.05 by ANOVA). Conversely, the measurements of EVLW did not show significant modification between the two supports whatever the posture. The ratio of the arterial oxygen tension to the fraction of inspired oxygen significantly increased in PP (P < 0.0001 by ANOVA) without any influence of the support.ConclusionIn comparison with a conventional foam mattress, the use of an air-cushioned mattress limited the increase in IAP and prevented the decrease in PDRICG related to PP in patients with ARDS. Conversely, the type of support did not influence EVLW or oxygenation.

Evaluation of left ventricular filling pressure by transthoracic Doppler echocardiography in the intensive care unit.

Objective To determine whether Doppler transmitral and pulmonary venous flow pattern is related to left ventricular filling pressures in critically ill patients. Design Prospective clinical investigation. Setting Medical intensive care unit of a university hospital. Patients Fifty-four mechanically ventilated patients (age, 63 ± 16 yrs) were investigated via transthoracic echocardiography and Doppler. Main diagnoses were pneumonia (31%), acute exacerbation of chronic obstructive pulmonary disease (24%), congestive heart failure (11%), and poisoning (11%). Interventions Doppler examinations were performed simultaneously with measurements of pulmonary artery occlusion pressure via a right heart catheter. Measurements and Main Results Pulmonary artery occlusion pressure correlated with transmitral peak E-wave velocity (r = .46) and E/A ratio (r = .55). Pulmonary artery occlusion pressure inversely correlated with deceleration time of the transmitral E-wave (r = −.52), pulmonary venous peak S-wave velocity (r = −.37), and systolic fraction of the pulmonary forward flow (r = −.56). An E/A ratio >2 predicted a pulmonary artery occlusion pressure >18 mm Hg with a positive predictive value of 100%. A duration of pulmonary venous A-wave reversal flow exceeding the duration of the transmitral A-wave forward flow predicted a pulmonary artery occlusion pressure >15 mm Hg with a positive predictive value of 83%. A systolic fraction of the pulmonary venous forward flow <0.4 predicted a pulmonary artery occlusion pressure >12 mm Hg with a positive predictive value of 100%. Conclusion Transmitral and pulmonary venous flow patterns measured by transthoracic Doppler echocardiography can be used to estimate the left ventricular filling pressure in critically ill patients.

Gallbladder abnormalities in medical ICU patients: An ultrasonographic study

Patients in the intensive care unit (ICU) have many risks factors for gallbladder stasis or acute acalculous cholecystitis (ACC), including fasting, total parenteral nutrition, sedation, mechanical ventilation, infection and shock. We have performed a prospective study to estimate the prevalence of ultrasonographic gallbladder abnormalities in 30 consecutive medical ICU patients during the first 2 days of their stay in the ICU. Two patients had previously undergone cholecystectomy and were excluded from the study. Seventeen (61%) of the remaining 28 patients presented with gall-bladder abnormalities. Considering three major criteria of ACC, 14 patients (50%) presented with either sludge (25%), wall thickening (22%) or hydrops (11%). However, none of the patients needed a surgical procedure during the study because of gallbladder disease. We conclude that an important proportion of ICU patients presented with gallbladder abnormalities shown by ultrasonography and that this may have implications for establishing a diagnosis of ACC using ultrasonographic criteria.

Haemodynamic effects of hyperbaric hyperoxia in healthy volunteers: an echocardiographic and Doppler study

In the present study, we observed the haemodynamic changes, using echocardiography and Doppler, in ten healthy volunteers during 6 h of compression in a hyperbaric chamber with a protocol designed to reproduce the conditions as near as possible to a real dive. Ambient pressure varied from 1.6 to 3 atm (1 atm=101.325 kPa) and partial pressure of inspired O2 from 1.2 to 2.8 atm. Subjects performed periods of exercise with breathing through a closed-circuit self-contained underwater breathing apparatus (SCUBA). Subjects did not eat or drink during the study. Examinations were performed after 15 min and 5 h. After 15 min, stroke volume (SV), left atrial (LA) diameter and left ventricular (LV) end-diastolic diameter (LVEDD) decreased. Heart rate (HR) and cardiac output (CO) did not vary, but indices of the LV systolic performance decreased by 10% and the LV meridional wall stress increased by 17%. After 5 h, although weight decreased, the serum protein concentration increased. Compared with values obtained after 15 min, SV and CO decreased, but LV systolic performance, LA diameter, LVEDD and LV meridional wall stress remained unchanged. Compared with the reference values obtained at sea level, total arterial compliance decreased, HR remained unchanged and CO decreased. In conclusion, hyperbaric hyperoxia results in significant haemodynamic changes. Initially, hyperoxia and the SCUBA system are responsible for reducing LV preload, increasing LV afterload and decreasing LV systolic performance, although CO did not change. Prolonged exposure resulted in a further decrease in LV preload, because of dehydration, and in a further increase in LV afterload, due to systemic vasoconstriction, with the consequence of decreasing CO.

Could hyperoxic ventilation impair oxygen delivery in septic patients

Objective:  In critically ill patients, a decrease in whole body oxygen consumption under hyperoxia has been reported and this could be related to hyperoxia‐induced arterial changes. We investigated changes in brachial artery circulation and tone during short‐term hyperoxic ventilation in septic patients.

Left-sided superior vena cava: diagnosis by magnetic resonance imaging

Abstract We describe a case of left-sided superior vena cava. The diagnosis was suggested by chest radiograph after central venous catheter placement. This was subsequently confirmed by magnetic resonance imaging.

Echocardiography on HIV patients admitted to the ICU

A prospective echocardiographic study was conducted in 68 patients with the human immunodeficiency virus (HIV) admitted to the intensive care unit (ICU) (C3 stage 78 %, i. v. drug abuse 71 %) in order, firstly to, assess the prevalence of cardiac abnormalities, and, secondly, to make an early therapeutic decision. Only five patients presented clinical evidence of cardiac disease. Echocardiographic abnormalities were identified in 35 patients (51 %): pericardial effusion: 20 cases (29 %), with tamponade in 2 cases that led to an immediate pericardiocentesis. Left ventricular dysfunction: 15 cases (22%) requiring treatment of cardiac failure. Mitral bioprothesis rupture in 1 patient that led to a surgical procedure. Vegetations of the tricuspid valve in 3 drug addicts (4 %) requiring early antibiotic treatment. Echocardiography proved to be very helpful in detecting hidden cardiac dysfunctions. It is immensely valuable in ICU management of HIV patients, since prompt initiation of appropriate treatment is essential.

Maladie de Crohn ou tuberculose digestive: complications liées à une erreur diagnostique

Resume Introduction Nous rapportons l’observation d’un patient atteint de tuberculose avec manifestations digestives mais traite initialement pour maladie de Crohn. Le traitement immunosuppresseur a conduit a une majoration et a une dissemination de l’atteinte tuberculeuse. Observation Un patient de 50 ans a ete hospitalise en reanimation pour detresse respiratoire dans le cadre d’une tuberculose disseminee. Apres une evolution respiratoire satisfaisante sous traitement anti-tuberculeux, un syndrome abdominal occlusif a revele une stenose ileale post-tuberculeuse. Commentaires Il est essentiel de differencier les 2 pathologies en raison des implications therapeutiques de la maladie de Crohn, pouvant amener a une explosion de la symptomatologie tuberculeuse. La prise en charge de cette derniere est medicale, avec une chirurgie reservee aux complications de type obstruction, fistulisation, perforations ou hemorragies.