Stress-related biomarkers of dream recall and implicit memory under anaesthesia.

The aim of this study was to investigate whether auditory presentation of a story during general anaesthesia might influence stress hormone changes and thus affecting dream recall and/or implicit memory. One hundred and ten patients were randomly assigned either to hear a recording of a story through headphones or to have routine care with no auditory recording while undergoing laparoscopic cholecystectomy. Anaesthesia was standardised. Blood samples for cortisol and prolactin assays were collected 20 min before anaesthesia and 5 min after pneumoperitoneum. Dream recall and explicit/implicit memory were investigated upon awakening from anaesthesia and approximately 24 h after the end of the operation. Auditory presentation was associated with lower intra-operative serum prolactin concentration compared with control (p = 0.0006). Twenty-seven patients with recall of dreaming showed higher intra-operative prolactin (p = 0.004) and lower cortisol (p = 0.03) concentrations compared with those without dream recall. The knowledge of this interaction might be useful in the quest to ensure postoperative amnesia.

EPO modulation in a 14-days undersea scuba dive.

Erythropoiesis is affected during deep saturation dives. The mechanism should be related to a downregulation of serum Erythropoietin (s-EPO) concentration or to a toxic effect of the hyperbaric hyperoxia. We evaluated s-EPO and other haematological parameters in 6 scuba divers before, during and after a 14-days guinness saturation dive (8-10 m). Athletes were breathing air at 1.8-2 ATA, under the control of a team of physicians. Serum parameters were measured before diving (T0) and: 7 days (T1), 14 days (T2) after the beginning of the dive and 2 h (T3) and 24 h (T4) after resurfacing. Hgb, and many other haematological parameters did not change whereas Ht, s-EPO, the ratio between s-EPO predicted and that observed and reticulocytes (absolute, percent) declined progressively from T0 to T3. At T4 a significant rise in s-EPO was observed. Hgb did not vary but erythropoiesis seemed to be affected as s-EPO and reticulocyte counts showed. All these changes were statistically significant. The experiment, conducted in realistic conditions of dive length, oxygen concentration and pressure, allows us to formulate some hypotheses about the role of prolonged hyperbarism on erythropoiesis. The s-EPO rise, 24 h after resurfacing, is clearly documented and related to the "Normobaric Oxygen Paradox". This evidence suggests interesting hypotheses for new clinical applications such as modulation of s-EPO production and Hgb content triggered by appropriate O2 administration in pre-surgical patients or in some anemic disease.

Split spectrum: a multi-channel approach to elastic optical networking.

This paper introduces Split Spectrum, which enhances elastic optical networking by splitting a bulk traffic demand into multiple channels, when a single-channel transmission is prohibited by distance or spectrum availability. We performed transmission simulations to determine the maximum reach as a function of modulation format (dual polarization BPSK, QPSK, 16QAM), baud-rate (from 5 to 28 GBd), and number of ROADMs, for a Nyquist WDM super-channel with subcarrier spacing equal to 1.2 × baud-rate. Performance evaluation on two representative topologies shows that, compared to the previously proposed elastic optical networking, Split Spectrum doubles the zero-blocking load and achieves 100% higher network spectral efficiency at zero-blocking loads as a result of extended transmission distance and efficient utilization of spectrum fragments.

Arthroscopic repair of massive rotator cuff tear. The role of the LHB distal tenotomy.

PURPOSE: The aim of the study was to evaluate the results of an all arthroscopic technique for the treatment of massive rotator cuff tears using the long head of biceps as a graft to reconstruct the superior capsule and to reinforce the cuff. METHODS: A retrospective review of a consecutive series of arthroscopic repair of massive rotator cuff tears using the long head of biceps tendon was conducted. Twenty-five patients underwent surgery, and none were lost at follow-up. Minimum follow-up period was more than 12 months. Constant, UCLA and VAS scores as clinical outcome were analyzed. Time for surgical procedures was also registered. Two alternative procedures (transosseous or anchors) were employed to fix laterally the long head of biceps to the greater tuberosity and to reinforce the cuff. This choice was essentially determined by the bone quality of the greater tuberosity. RESULTS: All patients of both groups (Transosseous: 15 and Anchors: 10) showed a significant improvement of clinical and functional scores. Difference of the operative times between two procedures was statistically significant in favor of the anchor approach. No intraoperative complications were recorded. Postoperative shoulder stiffness was found in two male patients. In no case biceps tenodesis was performed: Popeye sign was easily detected in 16 patients but they did not complain any superior arm pain and weakness. CONCLUSION: This technique represents a valid solution for treatment of massive rotator cuff tears resulting safe, easier and cost saving in comparison with other published techniques.

Beach nourishment using sediments from relict sand deposit: Effects on subtidal macrobenthic communities in the Central Adriatic Sea (Eastern Mediterranean Sea-Italy).

Nowadays nourishment is the most popular shore reconstruction strategy to counteract erosion of coastal areas. Sediments used for nourishment can have terrestrial or marine origin. This study analysed the effects of nourishment with relict sand on the subtidal macrobenthic communities and on the surface sediment at 7 sites of the Marche Region (Central Adriatic Sea, Italy). Samples for biological and physical analyses were collected in each site before and after nourishment. One year after nourishment the presence of the relict sands used for the replenishment is still visible in the sediment of each site. In the same period macrobenthic communities are characterised by the dominance of a few species able to avoid burial and suffocation phenomena, showing a low variability respect to the communities present before.

Exposure to noise during continuous positive airway pressure: influence of interfaces and delivery systems.

BACKGROUND: We measured noise intensity and perceived noisiness during continuous positive airway pressure (CPAP) performed with two interfaces (face-mask, helmet) and four delivery systems. METHODS: Eight healthy volunteers received CPAP in random order with: two systems provided with a flow generator using the Venturi effect and a mechanical expiratory valve (A: Venturi, Starmed; B: Whisperflow-2, Caradyne Ltd); one 'free-flow' system provided with high flow O(2) and air flowmeters, an inspiratory gas reservoir, and a water valve (C: CF800, Drägerwerk, AG); and a standard mechanical ventilator (Servoventilator 300, Siemens-Elema). Systems A, B, and C were tested with a face-mask and a helmet at a CPAP value of 10 cm H(2)O; the mechanical ventilator was only tested with the face mask. Noise intensity was measured with a sound-level meter. After each test, participants scored noisiness on a visual analog scale (VAS). RESULTS: The noise levels measured ranged from 57+/-11 dBA (mechanical ventilator plus mask) to 93+/-1 and 94+/-2 dBA (systems A and B plus helmet) and were significantly affected by CPAP systems (A and B noisier than C and D) and interfaces (helmet CPAP noisier than mask CPAP). Subjective evaluation showed that systems A and B plus helmet were perceived as noisier than system C plus mask or helmet. CONCLUSIONS: Maximum noise levels observed in this study may potentially cause patient discomfort. Less noisy CPAP systems (not using Venturi effect) and interfaces (facial mask better than helmet) should be preferred, particularly for long or nocturnal treatments.

Leptin and perioperative neuroendocrine stress response with two different anaesthetic techniques.

BACKGROUND: Stress response to surgery is modulated by several factors, including magnitude of the injury, pain, type of procedure and choice of anaesthesia. Our purpose was to compare intra- and post-operative hormonal changes during total intravenous anaesthesia (TIVA) using propofol and remifentanil vs. sevoflurane anaesthesia in a low stress level surgical model (laparoscopy). METHODS: We randomly allocated 18 patients undergoing laparoscopic surgery for benign ovarian cysts in two groups to receive either TIVA (group A=9) or sevoflurane anaesthesia (group B=9). Perioperative plasma levels of norepinephrine (NE), epinephrine (E), adrenocorticotropic hormone (ACTH), cortisol and leptin were measured. Blood samples were collected pre-operatively (time 0), 30 min after the beginning of surgery (time 1), after extubation (time 2), and 2 h (time 3) and 4 h after surgery (time 4). RESULTS: The comparative analysis between the groups shows significantly higher values of NE (P<0.001 at time 1 and P<0.01 at time 3), E (P<0.001 at times 1 and 2; P<0.01 at time 3 and P<0.05 at time 4), ACTH (P<0.001 at times 1 and 2; P<0.05 at time 3) and cortisol (P<0.001 at times 1 and 2; P<0.01 at time 3; P<0.05 at time 4) in group B. The serum values of leptin were not significantly different between the two groups. CONCLUSION: The choice of anaesthesia does not seem to affect the leptin serum levels but influences the release of stress response markers: ACTH, cortisol, NE and E.

Fibrinolysis or hypercoagulation during radical prostatectomy? An evaluation of thrombelastographic parameters and standard laboratory tests.

BACKGROUND AND OBJECTIVES: Radical prostatectomy is at high risk for intraoperative and postoperative bleeding due to surgical trauma, release of urokinase and tissue type plasminogen activator. We conducted this prospective, observational multi-centre study to assess the degree of systemic fibrinolysis or hypercoagulation in the perioperative period. We studied serial changes in standard laboratory values and in thrombelastographic (TEG; Haemoscope Corporation, Skokie, IL, USA) parameters including lysis at 30 and 60 min (LY-30, LY-60), alpha-angle (alpha) and maximum amplitude. METHODS: In all, 49 patients undergoing radical retropubic prostatectomy in five Italian University Hospitals were included. Blood samples were taken before surgery (T1), at the removal of the prostate (T2), 4 h after surgery (T3) and then 1 day after surgery (T4). Native blood samples were analysed using a thrombelastograph Haemoscope 5000 (Haemoscope Corporation). RESULTS: We did not see any relevant activation of fibrinolysis during any stage. Intraoperatively, we showed even more activated blood coagulation with consumption of fibrinogen and a reduced TEG percentage clot lysis. Only at the first postoperative sample point we saw a trend towards a more fibrinolytic state indicated by increasing partial thromboplastin time, LY-30 and LY-60 values, and a peak of the fibrin degradation product D-dimers. This is consistent with a normal reaction to the hypercoagulable state before and is unlikely to be due to an intraoperative tissue type plasminogen activator release. We found no evidence of an uncontrolled activation of fibrinolysis on the day after surgery. On the contrary, alpha-values which indicate the rate of clot formation and which increase during hypercoagulation showed the tendency to rise slightly compared with the preoperative value. CONCLUSION: Neither standard coagulation parameters nor TEG values showed any significant activation of fibrinolysis or of hypercoagulation in the preoperative period. Nevertheless, hypercoagulation seems to have a substantial clinical impact as it has been shown that cardiovascular complications and pulmonary embolism were the most common causes of death after retropubic prostatectomy.

A simple and low-power optical limiter for multi-GHz pulse trains.

We study the limiting-amplification capability of a saturated Semiconductor Optical Amplifier (SOA) followed by an optical band-pass filter. We experimentally demonstrate that this simple optical circuit can be effectively exploited to realize a low-power optical limiter for amplitude-modulated pulse trains at multi-GHz repetition rate. We report very large amplitude-modulation-reduction factors for the case of 20 and 40 GHz pulse trains that are super-imposed with modulating frequencies ranging from 100kHz to several GHz.

Molecular adsorbent recirculating system in liver transplantation: Safety and efficacy.

We assessed the safety and clinical efficacy of the Molecular Adsorbent Recirculating System (MARS) in liver failure patients admitted to our intensive care unit (ICU) from May 2000 to February 2006. Of 28 adult patients with bilirubin >15 mg/dL and hepatic encephalopathy (HE) grade > or =2 or hepato-renal syndrome, 22 patients were included in the study, because 6 patients were older than 65 years of age or showed recent alcohol abuse or extrahepatic malignancy. Patients were assigned to 2 groups according to whether MARS therapy was associated with a transplantation procedure: 11 patients received MARS therapy and liver transplantation (OLT group) and 11 patients received MARS therapy alone (non-OLT group). Five of 11 patients in the OLT group were listed for transplantation and 6 patients with graft failure for retransplantation. The patients in the OLT and non-OLT groups were similar in MELD, SOFA, and SAPS scores. All patients were stable and free from complications. MARS significantly reduced bilirubin, bile acids, and blood urea nitrogen (BUN) levels in both groups (P < .05), whereas a significant decrease in ammonia level was observed in the OLT group. Patient survival rates at 3 and 6 months in the OLT group were 91% and 73%, respectively, and in the non-OLT group, 9% and 9%, respectively (P < .001). MARS was safe and well tolerated, improving biochemical parameters, neurological function, and pruritus. In terms of survival, the use of MARS alone was not effective due to the high rate of multiple organ failure. Nevertheless, the association of MARS with a transplant/retransplantation procedure was highly effective.

Asymptomatic atrial fibrillation burden and thromboembolic events: piecing evidence together.

BACKGROUND: Contributory evidence on a direct association between asymptomatic atrial fibrillation (AF) burden and thromboembolic events is conflicting and contradictory. The aim of the article is to gather evidence available for a direct correlation between burden and stroke. METHODS: A literature search was performed to capture studies reporting data on the impact of asymptomatic AF burden on the risk of stroke. Data was then extracted from each included study including burden of AF, hazard ratio (HR) for stroke, and CHADS2 score. A random effects meta-analysis was carried out on the log-transformed HRs for different subgroups of AF burden. A meta-regression was performed on the two variables: burden of asymptomatic AF and CHADS2 score. RESULTS: The random-effect pooled analysis performed on a single subgroup of the six studies reporting data on HR, showed a HR of 2.150 (95% CI 1.523-3.003) for stroke during asymptomatic AF compared to sinus rhythm. At univariate meta-regression, no correlation was detected between burden of asymptomatic AF and HR for stroke (p-value 0,874). When CHADS2 score was included in the regression model as a covariate, no significant association was detected (p-value 0,939). CONCLUSION: A direct correlation between burden of asymptomatic AF and HR for stroke cannot be detected in our pooled analysis. However, due to the limitations acknowledged in the analysis, our findings need to be confirmed in large cohort studies.

The decrease in cytokine concentration during albumin dialysis correlates with the prognosis of patients with acute on chronic liver failure.

BACKGROUND AND AIM: The clearance of plasma cytokines by means of albumin dialysis (MARS) has been demonstrated in various studies involving patients affected by either acute liver failure (ALF) or acute on chronic liver failure. The aim of the study was to measure the plasma levels of TNF-alpha, IL-6, and IL-1beta in patients with ALF after each MARS treatment to evaluate the relationship between variations in cytokines levels and patient prognosis. MATERIALS AND METHODS: Ten patients with ALF undergoing several MARS treatments were enrolled (group 1). Blood samples were collected before and after each MARS treatment to measure TNF-alpha, IL-6, and IL-1beta, and other hematochemical parameters. We also enrolled 10 patients with ALF who underwent standard therapy (group 2) as well as a control group of 10 healthy subjects matched for sex and age (group 3). RESULTS: MARS reduced total bilirubin levels, biliary acids, BUN, ammonia, TNF-alpha, IL-6, and IL-1beta (P < .05). Moreover, the reduction in inflammatory cytokines levels and improved prognosis were related. CONCLUSIONS: We confirmed the therapeutic efficacy of MARS treatment for ALF, which appeared to be related to removal of toxins and inflammatory cytokines determine that which patients prognosis.

Improvement of mitochondrial function evaluated by ketoisocaproic acid breath test in patients with HCV infection undergoing albumin dialysis.

BACKGROUND AND AIM: Oxidative injury occurs as a direct result of hepatitis C virus (HCV) core protein expression both in vitro and in vivo, and may be due to a direct effect on mitochondria. The ketoisocaproic acid (KICA) breath test is a simple, reliable, and noninvasive test to evaluate hepatic mitochondrial function. Albumin dialysis (MARS) is an effective bridge treatment for patients with acute failure superimposed on chronic liver disease. The aim of our study was to evaluate the improvement of mitochondrial function measured by KICA in patients undergoing MARS for acute-on-chronic HCV liver failure. MATERIALS AND METHODS: Five patients with HCV chronic infection undergoing MARS treatment for acute decompensation were enrolled. Before and after each MARS treatment, patients underwent blood testing for the main hematochemical parameters as well as for mitochondrial function by the KICA breath test and the arterial ketone bodies ratio (AKBR). RESULTS: MARS treatment effectively decreased the serum level of total bilirubin, bile acids, urea, and ammonium. Moreover, MARS treatment produced an increase in AKBR and in the cumulative percentage of (13)CO(2) recovered in exhaled air 2 hours after KICA ingestion. CONCLUSION: Liver mitochondrial function appears to be beneficially affected by MARS treatment.

Catholic university experience with molecular adsorbent recycling system in patients with severe liver failure.

BACKGROUND AND AIM: Molecular adsorbent recycling system (MARS) treatment is able to remove both hydrosoluble and small- and medium-sized lipophilic toxins. MARS plays an important role in modifying liver failure complications, such as hepatorenal syndrome and hepatic encephalopathy. We sought to evaluate the clinical efficacy and safety of a MARS device in a consecutive series of hepatic failure patients. MATERIALS: Twenty patients with acute liver failure, transplantation failure, or acute on chronic liver failure fulfilled the inclusion criteria of total bilirubin > or =10 mg/dL and at least one of the following: hepatic encephalopathy (HE) > or =II grade, hepatorenal syndrome (HRS) for chronic patients or total bilirubin > or =5 mg/dL and HE > or =I grade for acute patients. RESULTS: MARS was able to reduce cholestatic parameters and improve neurologic status and renal function parameters in all treated patients. We also observed an improvement in the 3-month survival rate compared to the expected outcome in patients with MELD scores between 20 and 29, as well as 30 and 39. CONCLUSIONS: Based on these results, we confirm the safety and clinical efficacy of MARS treatment, with the best results in patients with MELD score of 20 to 29. Further studies are necessary to confirm whether this treatment is able to modify patient outcomes and prognosis.

Risk of pocket hematoma in patients on chronic anticoagulation with warfarin undergoing electrophysiological device implantation: a comparison of different peri-operative management strategies.

OBJECTIVE: Periprocedural management of warfarin remains challenging in patients requiring electrophysiological device surgery. For patients at high risk of thromboembolic events, guidelines recommend bridging therapy with heparin; however, this strategy is associated with a high risk of pocket hematoma. This paper systematically reviews studies appraising the risk of pocket hematoma with different perioperative anticoagulation strategies. METHODS: All relevant studies identified in MEDLINE/PubMed, The Cochrane Collaboration CENTRAL, clinicaltrials.org and in bibliographies of key articles. Estimates were combined using a fixed effects model. Heterogeneity was assessed by p values of χ2 statistics and I2. Publication bias was assessed by visual examination of funnel plots and by Egger test. Fifteen studies enrolling 5911 patients met all inclusion criteria and were included in this review. RESULTS: Heparin bridging compared with no heparin was associated with increased risk of pocket hematoma (OR = 4.47, 95% CI 3.21-6.23, p < 0.00001), and prolonged hospital stay (9.13 ± 1.9 days vs. 5.11 ± 1 .39 days, p < 0.00001). Warfarin continuation was not associated with increased pocket hematoma compared to warfarin discontinuation (p = 0.38), but was associated with reduced risk of pocket hematoma compared with heparin bridging (OR = 0.37, 95% CI 0.2-0.69, p = 0.002). Thromboembolic complications were reduced with heparin bridging vs. no heparin (0.50% vs.1.07%, p = 0.02), and no significant differences were reported between heparin bridging vs. warfarin continuation (p = 0.83). CONCLUSIONS: Heparin bridging is associated with a higher risk of pocket hematoma and a prolonged hospital stay. Perioperative continuation of warfarin reduces the occurrence of pocket hematoma compared with heparin bridging without any significant differences in thromboembolic complications.

Volatile anesthesia in bariatric surgery.

BACKGROUND: Obesity causes anesthesiologists a broad variety of perioperative theoretical and practical problems. The aim of this study was to compare two protocols of anesthesia employing Isoflurane and Sevoflurane and evaluate the cardiorespiratory parameters, postoperative recovery and analgesia. METHODS: 90 patients underwent biliopancreatic diversion. 60 patients (group A) received Isoflurane and 30 patients (group B) were anesthetized with Sevoflurane. Intraoperative monitoring consisted of EKG, invasive arterial pressure, SpO2, EtCO2, Etanest, Spirometry, urinary output and TOF. Cardiorespiratory parameters and end tidal expiratory concentrations of volatile agents were collected during specific phases of surgery: 1) before induction of anesthesia, 2) after intubation, 3) after skin incision, 4) after positioning of costal retractors, 5) in the reverse Trendelenburg position, 6) end of surgery. During the postoperative period the Aldrete test was carried out to evaluate the recovery from anesthesia. VAS was administered for 6 hours after the end of surgery to set the quality of analgesia. RESULTS: No statistically significant differences in cardiorespiratory parameters were found between the two groups. Extubation time was significantly less in the Sevoflurane Group than in the Isoflurane (15 +/- 7 min vs 24 +/- 5 min, p < 0.05). The Sevoflurane Group showed an Aldrete score significantly higher than the Isoflurane (8.8 +/- 0.3 vs 8.1 +/- 0.4, p < 0.05). VAS values did not show statistical differences. CONCLUSION: The introduction of Sevoflurane, a volatile agent with rapid pharmacokinetic properties, seems to offer an interesting application in these patients.

Comparison of positive end-expiratory pressure with reverse Trendelenburg position in morbidly obese patients undergoing bariatric surgery: effects on hemodynamics and pulmonary gas exchange.

BACKGROUND: Anesthetized morbidly obese patients often exhibit impaired pulmonary gas exchanges, mostly because of a reduction in functional residual capacity. At present, several approaches are suggested to ventilate these patients. METHODS: The efficiency of positive end-expiratory pressure (PEEP) and reverse Trendelenburg position (RTP) were compared in order to improve oxygenation in 20 morbidly obese patients undergoing bariatric surgery. RESULTS: Both PEEP and RTP determined a significant decrease in alveolar-arterial oxygen difference and an increase in total respiratory compliance (Ctot). RTP resulted in lower airway pressures than PEEP with similar improvements in Ctot and oxygenation. Concerning hemodynamic parameters, cardiac output (CO) significantly decreased with both PEEP and RTP. CONCLUSIONS: RTP and PEEP can be considered adequate ventilatory settings for morbidly obese patients, without any significant difference with regard to gas exchange improvement. However, the decrease in CO may partially counteract the beneficial effects on oxygenation of these ventilatory settings.

Plasma and intraerythrocyte amino-acid levels during and after haemodialysis in acute renal failure.

A study is carried out on the variations of plasma and blood red cells free amino acid concentrations secondary to haemodialysis in patients suffering from acute renal failure. A reduction in plasma free amino acid pool has been observed in patients undergoing to many periodic haemosialysis, but no significant differences occur in plasma aminogram between before and after a single dyalitic procedure. Significant alterations were also observed in blood red cells aminogram, and this may be interpreted as reflex of intracellular omeostatic mechanisms for the maintenance of normal plasma free aminoacid pattern.

Effects of acid-base abnormalities on blood capacity of transporting CO(2): adverse effect of metabolic acidosis.

OBJECTIVE: To investigate the effects of some acid-base abnormalities on blood capacity of transporting CO(2). DESIGN: Prospective study. SETTING: General and Cardiosurgical ICUs of a University hospital. PATIENTS: Six groups of ten patients characterized by: metabolic alkalosis; respiratory alkalosis; absence of acid-base abnormalities; metabolic acidosis; uncompensated respiratory acidosis; and compensated respiratory acidosis. MEASUREMENTS AND RESULTS: The CO(2) dissociation curve, Haldane effect, and the ratio Ra-v between Ca-vCO(2) and Pa-vCO(2) were calculated from arterial and mixed-venous blood gas analyses. The CO(2) dissociation curve was shifted upwards by metabolic alkalosis and compensated respiratory acidosis and downwards by metabolic acidosis. The slope of the curve was unaffected, but CO(2) transport not due to Haldane effect was significantly lower in respiratory acidosis since the slope was less steep at higher PCO(2) values. In comparison with controls, patients affected by metabolic acidosis showed lower Haldane effect values (0.18+/-0.15 vs 0.59+/-0.26 ml of CO(2) per ml of arterial-mixed venous O(2) content difference; P <.05) and Ra-v values (0.43+/-0.10 vs 0.84+/-0.17 ml of CO(2) transported by 100 ml of blood per Torr of arterial-mixed venous PCO(2) gradient; P <.05). CONCLUSIONS: Our findings suggest that acid-base abnormalities, particularly metabolic acidosis, markedly affect blood capacity of transporting CO(2) and may worsen tissue hypercarbia associated with hypoperfusion. However, because of possible errors due to small measurements and the assumptions of the method, in the future definitive clarification will require the construction of original CO(2) dissociation curves for each acid-base abnormality.

Predictors of failure of noninvasive positive pressure ventilation in patients with acute hypoxemic respiratory failure: a multi-center study.

CONTEXT: In patients with hypoxemic acute respiratory failure (ARF), randomized studies have shown noninvasive positive pressure ventilation (NPPV) to be associated with lower rates of endotracheal intubation. In these patients, predictors of NPPV failure are not well characterized. OBJECTIVE: To investigate variables predictive of NPPV failure in patients with hypoxemic ARF. DESIGN: Prospective, multicenter cohort study. SETTING: Eight Intensive Care Units (ICU) in Europe and USA. PATIENTS: Of 5,847 patients admitted between October 1996 and December 1998, 2,770 met criteria for hypoxemic ARF. Of these, 2,416 were already intubated and 354 were eligible for the study. RESULTS: NPPV failed in 30% (108/354) of patients. The highest intubation rate was observed in patients with ARDS (51%) or community-acquired pneumonia (50%). The lowest intubation rate was observed in patients with cardiogenic pulmonary edema (10%) and pulmonary contusion (18%). Multivariate analysis identified age > 40 years (OR 1.72, 95% CI 0.92-3.23), a simplified acute physiologic score (SAPS II) > or = 35 (OR 1.81, 95% CI 1.07-3.06), the presence of ARDS or community-acquired pneumonia (OR 3.75, 95% CI 2.25-6.24), and a PaO2:FiO2 < or = 146 after 1 h of NPPV (OR 2.51, 95% CI 1.45-4.35) as factors independently associated with failure of NPPV. Patients requiring intubation had a longer duration of ICU stay ( P < 0.001), higher rates of ventilator-associated pneumonia and septic complications ( P < 0.001), and a higher ICU mortality ( P < 0.001). CONCLUSIONS: In hypoxemic ARF, NPPV can be successful in selected populations. When patients have a higher severity score, an older age, ARDS or pneumonia, or fail to improve after 1 h of treatment, the risk of failure is higher.