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Biomedical subjects

P Cluzel

Publications and source records attributed to P Cluzel.

At least 37 records · Page 2Linked to original sources
PubMed2000

Evaluation of air trapping at CT: comparison of continuous-versus suspended-expiration CT techniques.

PURPOSE: To compare thin-section computed tomographic (CT) scans obtained during suspended end expiration with helical CT scans obtained during continuous expiration for the assessment of air trapping. MATERIALS AND METHODS: Forty-nine patients with an airway disease were examined with suspended-end-expiration CT after a 6-8-second expiratory maneuver, which was followed with continuous-expiration CT during a 10-second expiratory maneuver. The extent of expiratory air-trapping areas was calculated by two observers by using a semiquantitative grid score. The relative decrease in attenuation in the areas of air trapping was evaluated with a visual continuous-scale score. RESULTS: Air trapping was noted in 36 and 35 patients with continuous-expiration CT and with suspended-end-inspiration CT, respectively. The extents of and relative attenuation decreases in air-trapping areas in patients with air-trapping areas on at least one expiratory CT scan increased significantly in scans obtained with continuous-expiration CT compared with those obtained with suspended-end-expiration CT, respectively, with mean extent scores of 0.24 +/- 0.20 (SD) and 0.18 +/- 0.20 (paired t test, P: =.001) respectively, and with mean relative contrast decrease scores of 0.35 +/- 0.23 and 0.27 +/- 0.23 (paired t test, P: =.007), respectively. CONCLUSION: When suspended-end-expiration CT images are ambiguous, complementary continuous-expiration CT can be used to improve the conspicuity and apparent extent of air trapping.

Adolescent↗
PubMed2000

Role of the heart in the loss of aeration characterizing lower lobes in acute respiratory distress syndrome. CT Scan ARDS Study Group.

In the acute respiratory distress syndrome (ARDS), lower lobes appear essentially non-aerated in contrast to upper lobes whose aeration can be preserved in some patients. The aim of this study was to assess the mechanical compression exerted by the heart on lower lobes in patients with ARDS. Fourteen healthy volunteers and 38 patients with ARDS free of left ventricular failure were studied. Cardiorespiratory parameters were recorded and the cardiac dimensions, the pressure exerted by the heart on subjacent lower lobes, and the gas tissue ratio of lower lobes in the supine position were measured using computer tomography and Lungview, a specifically designed software. In patients with ARDS, the heart was larger and heavier than in healthy volunteers. The enlargement of the heart was mainly related to a left cardiac protrusion and the pressure exerted by the left heart on the lower lobes was higher in patients with ARDS than in healthy volunteers (8 +/- 3 g. cm(-)(2) versus 6 +/- 1 g. cm(-)(2), p < 0.01). As a consequence, the faction of gas represented 62% of the left lower lobes in healthy volunteers and 12% only in patients with ARDS. The present study demonstrates that apart from the already known anteroposterior and cephalocaudal gradients of pressure depending on the lung weight and abdominal pressure, the heart plays an important role in the dramatic loss of aeration characterizing lower lobes of patients with ARDS lying in the supine position.

Adult↗
PubMed2000

A computed tomographic scan assessment of endotracheal suctioning-induced bronchoconstriction in ventilated sheep.

This study was directed at assessing changes in bronchial cross-sectional surface areas (BCSA) and in respiratory resistance induced by endotracheal suctioning in nine anesthetized sheep. Cardiorespiratory parameters (Swan-Ganz catheter), respiratory resistance (inspiratory occlusion technique), BCSA, and lung aeration (computed tomography) were studied at baseline, during endotracheal suctioning, and after 20 consecutive hyperinflations. Measurements performed initially at an inspired oxygen fraction (FI(O(2))) of 0.3 were repeated at an FI(O(2)) of 1.0. At an FI(O(2)) of 0.3, endotracheal suctioning resulted in atelectasis, a reduction in BCSA of 29 +/- 23% (mean +/- SD), a decrease in arterial oxygen saturation from 95 +/- 3% to 87 +/- 12% (p = 0.02), an increase in venous admixture from 19 +/- 10% to 31 +/- 19% (p = 0. 006), and an increase in lung tissue resistance (DR(rs)) (p = 0. 0003). At an FI(O(2)) of 1.0, despite an extension of atelectasis and an increase in pulmonary shunt from 19 +/- 5% to 36 +/- 2% (p < 0.0001), arterial O(2) desaturation was prevented and BCSA decreased by only 7 +/- 32%. A recruitment maneuver after endotracheal suctioning entirely reversed the suctioning-induced increase in DR(rs) and atelectasis. In three lidocaine-pretreated sheep, the endotracheal suctioning-induced reduction of BCSA was entirely prevented. These data suggest that the endotracheal suctioning-induced decrease in BCSA is related to atelectasis and bronchoconstriction. Both effects can be reversed by hyperoxygenation maneuver before suctioning in combination with recruitment maneuver after suctioning.

Airway Resistance↗
PubMed2000

[Preservation of vascular and cardiac capital in the patient with chronic kidney failure].

Preservation of the vascular and cardiac capital is an essential objective at all times in patients with chronic renal failure, even before end-stage renal failure, at which time the urologist may need to perform surgical procedures on the urinary tract in the presence of uropathy. Medical and paramedical teams must be aware of the importance of preservation of the capital venous of the upper extremity and the risks of subclavian catheterization at this stage. When creating a vascular access, distal anastomoses should be preferred, sometimes at the cost of grafting, in order to preserve left ventricular function. Close collaboration with radiologists is now essential to manage complications of vascular accesses. The management of arteriovenous fistula after transplantation depends on many sometimes contradictory parameters and should be determined case by case. The importance of "economic" management of the patient's vascular and cardiac capital justifies global management of chronic renal failure by urologists perfectly familiar with the specific problems of these patients and trained to intervene throughout the course of the disease.

Cardiovascular Diseases↗
PubMed2000

[Endovascular treatment of aorto-iliac aneurysms. Made-to-measure endoprotheses increase the feasibility].

The authors describe their experience of tailoring endoprostheses for endovascular treatment of aorto-iliac aneurysms with components available on the market. Between January 1996 and December 1999, 188 aorto-iliac aneurysms were treated by tailor-made endoprostheses using self-expanding Z stents made of stainless steel compiled with polyester ligatures and covered with standard commercially available polyester prostheses. These endoprostheses were implanted with an 18 to 24 Fr (usually 20 Fr) introducer and positioned by a surgical approach. This method allows construction of tubular, bifurcated, digressive or occlusive endoprostheses associated with an extra-anatomical bypass graft. It increased the number of endovascular procedures for aorto-iliac aneurysms in the authors' department. This number has been further increased by using endoprostheses with an uncovered proximal or distal stent for cases with particularly short or angled necks and by using hybrid endoprostheses with one or more extremities without a stent, allowing surgical suture of the anastomosis. The authors' results show that tailoring endoprostheses considerably increased the feasibility of endovascular treatment of aorto-iliac aneurysms, even in unselected patients whilst providing an effectiveness and safety to justify the continuation of this experience.

Aortic Aneurysm, Abdominal↗
PubMed2000

[Epidermoid cancer of the kidney pelvis].

Squamous cell carcinoma of the renal pelvis is a rare tumour, mainly occurring in elderly patients with neglected and secondarily infected pyelocaliceal stones. It has a poor prognosis. The authors report the case of a 74-year old man with a destroyed and painful kidney containing a staghorn calculus for 30 years. The preoperative diagnosis was pyonephrosis, but nephrectomy, justified by the symptoms, showed that the kidney was invaded by a squamous cell carcinoma of the renal pelvis invading the psoas. The patient died 1 month after the operation. Treatment is essentially preventive by removal of staghorn calculi and management of chronic urinary tract infections.

Aged↗
PubMed1999

Focal nodular hyperplasia of the liver on ferumoxides-enhanced MR imaging: features on conventional spin-echo, fast spin-echo and gradient-echo pulse sequences.

The aim of this study was to assess the efficacy of a superparamagnetic iron oxide, ferumoxides, in the detection and characterization of focal nodular hyperplasia (FNH) on MR conventional spin-echo (SE), fast spin-echo (FSE) and gradient-echo (GRE) images. Fourteen adults with 27 FNHs were evaluated at 1.5 T before and after injection of ferumoxides. T1-weighted and T2-weighted SE, T2-weighted FSE and T2(*)-weighted GRE sequences were used and analysed qualitatively and quantitatively. One hundred percent of FNHs showed a significant postcontrast decrease in signal intensity on T2- and T2*-weighted images. Heavily T2-weighted SE images showed the maximum decrease in FNH signal-to-noise ratio (S/N). Postcontrast GRE T2(*)-weighted images improved the detection of the central scar and the delineation of FNHs and demonstrated the best lesion-to-liver contrast-to-noise ratio (C/N). Postcontrast T1-weighted SE images showed the least lesion-to-liver C/N. Ferumoxides-enhanced MR imaging can help detect and characterize FNH. Conventional pre- and postcontrast T2-weighted SE images and postcontrast GRE T2*-weighted images should be used preferentially.

Adult↗
PubMed1999

Endovascular treatment of aortoiliac aneurysms: made-to-measure stent-grafts increase feasibility.

We describe here our preliminary experience with use of a range of made-to-measure stent-grafts made from commercially available components. From January 1996 to June 1998, 94 aortoiliac aneurysms (AIA) were treated with stent-grafts that were made to measure using Z autoexpandable stainless steel stents connected with polyester sutures and covered with commercially available polyester vascular prostheses. These stent-grafts were implanted through 18 to 24 (typically 20) Fr commercially available introducers via a surgical remote access. Made-to-measure tubular, bifurcated, tapered, and/or blind stents combined with extraanatomic bypass designs increased the rate of endovascular treatment (ET) of AIA in this series. This rate was further increased through the use of uncovered proximal or distal stents when dealing with short or tortuous necks near major collaterals and through use of hybrid, partly surgical designs, one with stented and the other with stentless ends, the latter allowing for a surgically made anastomosis. The results of our experience with these techniques show that use of made to-measure stent-grafts greatly increases the feasibility of the ET of AIA among unselected patients while offering enough efficiency and safety to deserve further investigation.

Aortic Aneurysm, Abdominal↗
PubMed1999

A scanographic assessment of pulmonary morphology in acute lung injury. Significance of the lower inflection point detected on the lung pressure-volume curve.

The goal of this study was to assess lung morphology in patients with acute lung injury according to the presence or the absence of a lower inflection point (LIP) on the lung pressure-volume (P-V) curve and to compare the effects of positive end-expiratory pressure (PEEP). Eight patients with and six without an LIP underwent a spiral thoracic CT scan performed at zero end-expiratory pressure (ZEEP) and at two levels of PEEP: PEEP1 = LIP + 2 cm H2O and PEEP2 = LIP + 7 cm H2O, or PEEP1 = 10 cm H2O and PEEP2 = 15 cm H2O in the absence of an LIP. The volumes of air and tissue within the lungs were measured from the gas-tissue ratio and the volumes of overdistended and normally, poorly, and nonaerated lung areas were determined by the analysis of the frequency histogram distribution. In the ZEEP condition, although total lung volume, volume of gas, and volume of tissue were similar in both groups, the percentage of normally aerated lung was lower (24 +/- 22% versus 55 +/- 12%, p < 0.05) and the percentage of poorly aerated lung was greater (40 +/- 12% versus 23 +/- 8%, p < 0.05) in patients with an LIP than in patients without an LIP. Lung density histograms of patients with an LIP showed a unimodal distribution with a peak at 7 Hounsfield units (HU). Lung density histograms of patients without an LIP had a bimodal distribution, with a first peak at -727 HU and a second peak at 27 HU. Total respiratory system and lung compliances were lower in patients with an LIP whereas all other cardiorespiratory parameters were similar in the two groups. In both groups, PEEP induced an alveolar recruitment that was associated with lung overdistension only in patients without an LIP. The amount of lung overdistension was related to the volume of lung parenchyma, characterized by a CT number less than -800 HU before PEEP implementation (y = 0.52x + 4, R = 0.87, and p < 0.0001). This study shows that the presence or the absence of an LIP on the lung P-V curve is associated with differences in lung morphology. In patients without an LIP on the lung P-V curve, normally aerated lung areas coexist with nonaerated lung areas and increasing levels of PEEP result in lung overdistension rather than in additional alveolar recruitment. In patients with an LIP, air and tissue are more homogeneously distributed within the lungs and increasing levels of PEEP result in additional alveolar recruitment without lung overdistention.

Acute Disease↗
PubMed1999

Contrast-enhanced helical CT for pulmonary embolism detection: inter- and intraobserver agreement among radiologists with variable experience.

OBJECTIVE: The objective of this study was to evaluate inter- and intraobserver agreement in the diagnosis of central pulmonary embolism using contrast-enhanced helical CT among observers with variable experience in the interpretation of pulmonary CT angiograms. MATERIALS AND METHODS: Helical CT angiograms of 60 patients clinically suspected of having pulmonary embolism were analyzed retrospectively and independently by two chest radiologists, one cardiovascular radiologist, and three general radiologists. The films were rated a second time by the chest radiologists to assess intraobserver variability. Findings for pulmonary embolism were categorized as positive, negative, or indeterminate at the main, lobar, and segmental pulmonary artery levels. RESULTS: The observers interpreted 19-21 CT angiograms as positive for pulmonary embolism (mean, 19.7) and one to six as indeterminate (mean, 3.2). Agreement occurred among all observers in 50 patients (83.3%), among five observers in six patients (10.0%), among four observers in three patients (5.0%), and among three observers in one patient (1.7%). Interobserver agreement was very good (kappa, .85) for the diagnosis of pulmonary embolism on a per-patient basis. Agreement on a per-artery basis for all arteries was moderate (66%; kappa, .56); for lobar arteries was good (83%; kappa, .75); and for segmental arteries was moderate (57%; kappa, .47). Mean intraobserver agreement on a per-patient basis was very good (93%; kappa, .87). CONCLUSION: Inter- and intraobserver agreement in the diagnosis of pulmonary embolism with helical CT is very good despite a wide variety of experience among radiologists.

Adult↗
PubMed1998

Review article: Overview of medical treatments in unresectable hepatocellular carcinoma--an impossible meta-analysis?

BACKGROUND: Controversies surrounding medical treatment in patients with unresectable hepatocellular carcinoma continue to persist. AIM: To perform a meta-analysis of therapeutic modalities which had been evaluated in two or more randomized trials. METHODS: Fifty-two randomized trials were studied; only 30 were included. This overview identified seven therapeutic modalities which had been evaluated in two or more trials: adriamycin, 5-fluorouracil, interferon, percutaneous ethanol injection, transarterial chemotherapy, the combination of lipiodol with transarterial chemotherapy, and tamoxifen. RESULTS: Comparisons of survival between control groups showed substantial heterogeneity. There was no survival benefit at 1 year with adriamycin (mean difference 4%), 5-fluorouracil (mean difference -3%), percutaneous ethanol injection (mean difference 6%) or transarterial chemotherapy (mean difference -2%). For interferon, the survival benefit was significant with the Der Simonian & Laird method (mean difference 9%, 95% CI = 1-18%, P = 0.04) but not with the Peto et al. method (2.4 mean odds ratio, 95% CI = 0.9-6.8). The meta-analysis of tamoxifen showed a borderline survival benefit (mean difference 25%, 95% CI = 0-49%, P = 0.05). However, in sensitivity analyses, the survival benefit of tamoxifen was no longer significant. CONCLUSIONS: No treatment has clearly proven efficacy in survival. 5-Fluorouracil, adriamycin and transarterial chemotherapy were not associated with survival benefit at 1 year. The number of randomized controlled trials was insufficient to enable a conclusion to be reached for interferon and percutaneous ethanol injection. Controversy persists concerning tamoxifen efficacy. Interferon and tamoxifen require new randomized controlled trials on a larger population of patients.

Administration, Cutaneous↗
PubMed1998

Lymph node metastases: safety and effectiveness of MR imaging with ultrasmall superparamagnetic iron oxide particles--initial clinical experience.

PURPOSE: To evaluate the clinical and biologic safety of ultrasmall superparamagnetic iron oxide particles (AMI-227) as a contrast agent for magnetic resonance (MR) lymphography and to assess their efficacy for the differentiation of metastatic and benign nodes in patients with urologic and pelvic cancer. MATERIALS AND METHODS: Thirty adults suspected of having lymph node metastases underwent MR imaging before and 22-26 hours after intravenous infusion of AMI-227 (1.7 mg Fe/kg). Sixty histopathologically proved lymph nodes were analyzed on MR images, and 29 of these nodes were also analyzed quantitatively. RESULTS: AMI-227 was well tolerated with no major side effects. It allowed the detection of 10 additional nodes relative to those detected at MR imaging without AMI-227. None of the 27 metastatic nodes showed a decrease in signal intensity (SI) on AMI-227-enhanced images; nine of 27 metastatic nodes showed an increase in SI on T1-weighted images, probably resulting from altered capillary permeability in the tumor. A visually perceptible reduction in SI, indicating active AMI-227 uptake, was observed on postcontrast T2- and T2*-weighted images in 16 of 21 benign nodes. The SI ratio of benign nodes was lower than that of metastatic nodes on T2- and T2*-weighted images. The sensitivity of AMI-227-enhanced MR lymphography was 100%, and the specificity was 80%. CONCLUSION: AMI-227 is safe and may facilitate the differentiation of metastatic and benign nodes in patients with urologic and pelvic cancers.

Adult↗
PubMed1998

A computed tomography scan assessment of regional lung volume in acute lung injury. The CT Scan ARDS Study Group.

The lobar and cephalocaudal distribution of aerated and nonaerated lung and of PEEP-induced alveolar recruitment is unknown in acute lung injury (ALI). Dimensions of the lungs and volumes of aerated and nonaerated parts of each pulmonary lobe were measured using a computerized tomographic quantitative analysis and compared between 21 patients with ALI and 10 healthy volunteers. Distribution of PEEP-induced alveolar recruitment along the anteroposterior and cephalocaudal axis and influence of the resting volume of nonaerated lower lobes were also assessed. Anteroposterior and transverse dimensions of the lungs of the patients were similar to those of healthy volunteers, whereas cephalocaudal dimensions were reduced by more than 15%. Total lung volume (aerated plus nonaerated lung) was reduced by 27%. Volumes of upper and lower lobes were 99 and 48% of normal values. In addition to an anteroposterior gradient in the distribution of aerated and nonaerated areas, a cephalocaudal gradient was also observed. Nonaerated areas were predominantly found in juxtadiaphragmatic regions. PEEP-induced alveolar recruitment was more pronounced in nondependent than in dependent regions and in cephalad than in caudal regions. A significant correlation between resting volume of nonaerated lower lobes and regional PEEP-induced alveolar recruitment was observed. In ALI, loss of lung volume involves predominantly lower lobes. The thorax shortens along its cephalocaudal axis. PEEP-induced alveolar recruitment predominates in nondependent and cephalad lung regions and is inversely correlated with the resting volume of nonaerated lung.

Adult↗
PubMed1998

A lung computed tomographic assessment of positive end-expiratory pressure-induced lung overdistension.

The aim of this study was to assess positive end-expiratory pressure (PEEP)-induced lung overdistension and alveolar recruitment in six patients with acute lung injury (ALI) using a computed tomographic (CT) scan method. Lung overdistension was first determined in six healthy volunteers in whom CT sections were obtained at FRC and at TLC with a positive airway pressure of 30 cm H2O. In patients, lung volumes were quantified by the analysis of the frequency distribution of CT numbers on the entire lung at zero end-expiratory pressure (ZEEP) and PEEP. In healthy volunteers at FRC, the distribution of the density histograms was monophasic with a peak at -791 +/- 12 Hounsfield units (HU). The lowest CT number observed was -912 HU. At TLC, lung volume increased by 79 +/- 35% and the peak CT number decreased to -886 +/- 26 HU. More than 70% of the increase in lung volume was located below -900 HU, suggesting that this value can be considered as the threshold separating normal aeration from overdistension. In patients with ALI, at ZEEP the distribution of density histograms was either monophasic (n = 3) or biphasic (n = 3). The mean CT number was -319 +/- 34 HU. At PEEP 13 +/- 3 cm H2O, lung volume increased by 47 +/- 19% whereas mean CT number decreased to -538 +/- 171 HU. PEEP induced a mean alveolar recruitment of 320 +/- 160 ml and a mean lung overdistension of 238 +/- 320 ml. In conclusion, overdistended lung parenchyma of healthy volunteers is characterized by a CT number below -900 HU. This threshold can be used in patients with ALI for differentiating PEEP-induced alveolar recruitment from lung overdistension.

Adult↗
PubMed1998

Expiratory CT scans for chronic airway disease: correlation with pulmonary function test results.

OBJECTIVE: The purpose of our study was to correlate findings on expiratory CT scans with results of pulmonary function tests (PFTs) and to determine whether these techniques may be complementary in assessing airway obstruction. MATERIALS AND METHODS: Seventy-four patients with suspected chronic airway disease and 10 healthy nonsmokers underwent inspiratory and expiratory CT scans and PFTs. An air trapping score, corresponding to the ratio of the cross-sectional air trapping area versus the total cross-sectional lung area on expiratory CT, and a reduction score, representing the change in cross-sectional lung area at inspiration and expiration, were calculated using a quantitative grid. The two scores were then correlated with the results of the PFTs. RESULTS: Expiratory air trapping was seen in 18 (51%) of 35 patients with severe airway obstruction (forced expiratory volume in 1 sec [FEV1]:vital capacity < 80%) (group A), in 21 (72%) of 29 patients with predominantly small airways obstruction (abnormal flow-volume curve and FEV1:vital capacity > or = 80%) (group B1), and in four (40%) of 10 patients with normal PFT results (group B2). Expiratory air trapping was never seen in the 10 healthy subjects. Air trapping scores were 27%, 12%, and 8% for groups A, B1, and B2, respectively, with significant negative correlations with FEV1 (r = -.45), FEV1:vital capacity (r = -.31), and forced expiratory flow at 25% of vital capacity (r = -.57). Reduction scores were 18%, 30%, 35%, and 43%, for the groups A, B1, B2, and the healthy group, respectively, with significant correlations with all the PFT indexes (r = .35 to .66) except total lung capacity. CONCLUSION: Air trapping may permit detection of airway obstruction in patients with clinically suspected chronic airway disease even when PFTs are normal. Furthermore, expiratory CT allows one to calculate a reduction score for a cross-sectional lung area that appears to be better correlated with the degree of airway obstruction measured on PFTs.

Adult↗
PubMed1997

Factors influencing the tracheal fluctuation of inhaled nitric oxide in patients with acute lung injury.

BACKGROUND: Inhaled nitric oxide (NO) improves arterial oxygenation in patients with acute lung injury (ALI) by selectively dilating pulmonary vessels perfusing ventilated lung areas. It can be hypothesized that NO uptake from the lung decreases with increasing ventilation perfusion mismatch. This study was undertaken to determine the factors influencing the fluctuation of tracheal NO concentration over the respiratory cycle as an index of NO pulmonary uptake in patients with ALI. METHODS: By using a prototype system (Opti-NO) delivering a constant flow of NO only during the inspiratory phase, 3 and 6 ppm of NO were administered during controlled mechanical ventilation into a lung model and to 11 patients with ALI. All patients had a thoracic computed tomography (CT) scan. Based on an analysis of tomographic densities, lungs were divided into three zones: normally aerated (-1.000 to -500 Hounsfield units [HU]), poorly aerated (-500 to -100 HU), and nonaerated (-100 to +100 HU), and the volume of each zone was computed. Concentrations of NO in the inspiratory limb and trachea were continuously measured by a fast-response chemiluminescence apparatus. RESULTS: In the lung model, tracheal NO concentration was stable with minor fluctuation. In contrast, in patients, tracheal NO concentration fluctuated widely during the respiratory cycle (55 +/- 10%). Because uptake of NO from the lungs was absent in the lung model but present in the patients, this fluctuation was considered as an index of pulmonary uptake of NO. This was further substantiated by (1) the coincidence of the peak and minimum tracheal NO concentration with the end-inspiratory and end-expiratory phases, respectively, and (2) continued decrease of tracheal NO concentration during prolonged expiratory phase. In patients with ALI, the fluctuation of tracheal NO concentration expressed as the difference between inspiratory and expiratory NO concentrations divided by inspiratory NO concentration was greater at 6 ppm than at 3 ppm (P < 0.01), was linearly correlated with normally aerated lung volume, inversely correlated with alveolar dead space and with poorly aerated lung volume. CONCLUSION: In patients with ALI, fluctuation of tracheal NO concentration over the respiratory cycle can be considered as an index of NO uptake from the lungs that depends on aerated lung volume and perfusion of ventilated lung areas. At bedside, it may be used to follow the evolution of ventilation-perfusion mismatch.

Administration, Inhalation↗
PubMed1997

Inhaled nitric oxide in acute respiratory distress syndrome with and without septic shock requiring norepinephrine administration: a dose-response study.

BACKGROUND: The aim of this prospective study was to assess whether the presence of septic shock could influence the dose response to inhaled nitric oxide (NO) in NO-responding patients with adult respiratory distress syndrome (ARDS). RESULTS: Eight patients with ARDS and without septic shock (PaO2 = 95 +/- 16 mmHg, PEEP = 0, FiO2 = 1.0), and eight patients with ARDS and septic shock (PaO2 = 88 +/- 11 mmHg, PEEP = 0, FiO2 = 1.0) receiving exclusively norepinephrine were studied. All responded to 15 ppm inhaled NO with an increase in PaO2 of at least 40 mmHg, at FiO2 1.0 and PEEP 10 cmH2O. Inspiratory intratracheal NO concentrations were recorded continuously using a fast response time chemiluminescence apparatus. Seven inspiratory NO concentrations were randomly administered: 0.15, 0.45, 1.5, 4.5, 15, 45 and 150 ppm. In both groups, NO induced a dose-dependent decrease in mean pulmonary artery pressure (MPAP), pulmonary vascular resistance index (PVRI), and venous admixture (QVA/QT), and a dose-dependent increase in PaO2/FiO2 (P </= 0.012). Dose-response of MPAP and PVRI were similar in both groups with a plateau effect at 4.5 ppm. Dose-response of PaO2/FiO2 was influenced by the presence of septic shock. No plateau effect was observed in patients with septic shock and PaO2/FiO2 increased by 173 +/- 37% at 150 ppm. In patients without septic shock, an 82 +/- 26% increase in PaO2/FiO2was observed with a plateau effect obtained at 15 ppm. In both groups, dose-response curves demonstrated a marked interindividual variability and in five patients pulmonary vascular effect and improvement in arterial oxygenation were dissociated. CONCLUSION: For similar NOinduced decreases in MPAP and PVRI in both groups, the increase in arterial oxygenation was more marked in patients with septic shock.

Journal Article↗