Effects of superimposed tissue weight on regional compliance of injured lungs.

Computed tomography (CT), together with image analysis technologies, enable the construction of regional volume (VREG) and local transpulmonary pressure (PTP,REG) maps of the lung. Purpose of this study is to assess the distribution of VREG vs PTP,REG along the gravitational axis in healthy (HL) and experimental acute lung injury conditions (eALI) at various positive end-expiratory pressures (PEEPs) and inflation volumes. Mechanically ventilated pigs underwent inspiratory hold maneuvers at increasing volumes simultaneously with lung CT scans. eALI was induced via the iv administration of oleic acid. We computed voxel-level VREG vs PTP,REG curves into eleven isogravitational planes by applying polynomial regressions. Via F-test, we determined that VREG vs PTP,REG curves derived from different anatomical planes (p-values<1.4E-3), exposed to different PEEPs (p-values<1.5E-5) or subtending different lung status (p-values<3E-3) were statistically different (except for two cases of adjacent planes). Lung parenchyma exhibits different elastic behaviors based on its position and the density of superimposed tissue which can increase during lung injury.

Regional distribution of lung compliance by image analysis of computed tomograms.

Computed tomography (CT) can yield quantitative information about volume distribution in the lung. By combining information provided by CT and respiratory mechanics, this study aims at quantifying regional lung compliance (CL) and its distribution and homogeneity in mechanically ventilated pigs. The animals underwent inspiratory hold maneuvers at 12 lung volumes with simultaneous CT exposure at two end-expiratory pressure levels and before and after acute lung injury (ALI) by oleic acid administration. CL and the sum of positive voxel compliances from CT were linearly correlated; negative compliance areas were found. A remarkably heterogeneous distribution of voxel compliance was found in the injured lungs. As the lung inflation increased, the homogeneity increased in healthy lungs but decreased in injured lungs. Image analysis brought novel findings regarding spatial homogeneity of compliance, which increases in ALI but not in healthy lungs by applying PEEP after a recruitment maneuver.

Development and results of Puglia adult cardiac surgery registry.

AIMS: To evaluate the feasibility of a cardiac surgery registry and to describe patients' characteristics, type of procedures performed, incidence of postoperative complications with short and middle-term mortality. METHODS: A database with clinical information and details on cardiac surgical operations was implemented by Puglia Health Regional Agency to collect data of each cardiac surgery procedure performed in the seven adult cardiac surgery centres of the region. Health regional agency personnel guaranteed data accuracy and quality control procedures. Mortality after the discharge was evaluated for residents in Puglia by linking clinical data to the Health Information System. RESULTS: From January 2011 to December 2012, 6429 operations were performed. All operations were included in the registry with very high completeness of collected data (95.3% per patient). The majority of the operations performed were coronary artery bypass graft alone (41.1%), valve surgery alone (26.2%), coronary artery bypass graft and valve surgery (11.4%), or valve with other surgery (11.8%). During a median follow-up of 12 months (interquartile range 6-18 months), 211 deaths were detected after the discharge. Overall, cumulative mortality from the operation was 8.2% at 6 months and 9.5% at 12 months. CONCLUSION: Implementation of a regional clinical registry of cardiac surgery is feasible with a great level of accuracy and the evaluation of mid-term mortality overcomes the limited value of hospital mortality. An accurate cardiac surgery registry elicits epidemiologic evaluations, comparisons between expected and observed mortality, incidence of postoperative complications and encourages a reliable public reporting.

Antithrombin administration in patients with low antithrombin values after cardiac surgery: a randomized controlled trial.

BACKGROUND: Antithrombin (AT) concentrations are reduced after cardiac surgery with cardiopulmonary bypass compared with the preoperative levels. Low postoperative AT is associated with worse short- and mid-term clinical outcomes. The aim of the study is to evaluate the effects of AT administration on activation of the coagulation and fibrinolytic systems, platelet function, and the inflammatory response in patients with low postoperative AT levels. METHODS: Sixty patients with postoperative AT levels of less than 65% were randomly assigned to receive purified AT (5000 IU in three administrations) or placebo in the postoperative intensive care unit. Thirty patients with postoperative AT levels greater than 65% were observed as controls. Interleukin 6 (a marker of inflammation), prothrombin fragment 1-2 (a marker of thrombin generation), plasmin-antiplasmin complex (a marker of fibrinolysis), and platelet factor 4 (a marker of platelet activation) were measured at six different times. RESULTS: Compared with the no AT group and control patients, patients receiving AT showed significantly higher AT values until 48 hours after the last administration. Analysis of variance for repeated measures showed a significant effect of study treatment in reducing prothrombin fragment 1-2 (p=0.009; interaction with time sample, p=0.006) and plasmin-antiplasmin complex (p<0.001; interaction with time sample, p<0.001) values but not interleukin 6 (p=0.877; interaction with time sample, p=0.521) and platelet factor 4 (p=0.913; interaction with time sample, p=0.543). No difference in chest tube drainage, reopening for bleeding, and blood transfusion was observed. CONCLUSIONS: Antithrombin administration in patients with low AT activity after surgery with cardiopulmonary bypass reduces postoperative thrombin generation and fibrinolysis with no effects on platelet activation and inflammatory response.

Risk stratification for in-hospital mortality after cardiac surgery: external validation of EuroSCORE II in a prospective regional registry.

OBJECTIVES: To evaluate performance of the European System for Cardiac Operation Risk Evaluation (EuroSCORE II), to assess the influence of model updating and to derive a hierarchical tree for modelling the relationship between EuroSCORE II risk factors and hospital mortality after cardiac surgery in a large prospective contemporary cohort of consecutive adult patients. METHODS: Data on consecutive patients, who underwent on-pump cardiac surgery or off-pump coronary artery bypass graft intervention, were retrieved from Puglia Adult Cardiac Surgery Registry. Discrimination, calibration, re-estimation of EuroSCORE II coefficients and hierarchical tree analysis of risk factors were assessed. RESULTS: Out 6293 procedures, 6191 (98.4%) had complete data for EuroSCORE II assessment with a hospital mortality rate of 4.85% and EuroSCORE II of 4.40 ± 7.04%. The area under the receiver operator characteristic curve (0.830) showed good discriminative ability of EuroSCORE II in distinguishing patients who died and those who survived. Calibration of EuroSCORE II was preserved with lower predicted than observed risk in the highest EuroSCORE II deciles. At logistic regression analysis, the complete revision of the model had most of re-estimated regression coefficients not statistically different from those in the original EuroSCORE II model. When missing values were replaced with the mean EuroSCORE II value according to urgency and weight of intervention, the risk score confirmed discrimination and calibration obtained over the entire sample. A recursive tree-building algorithm of EuroSCORE II variables identified three large groups (55.1, 17.1 and 18.1% of procedures) with low-to-moderate risk (observed mortality of 1.5, 3.2 and 6.4%) and two groups (3.8 and 5.9% of procedures) at high risk (mortality of 14.6 and 32.2%). Patients with low-to-moderate risk had good agreement between observed events and predicted frequencies by EuroSCORE II, whereas those at greater risk showed an underestimation of expected mortality. CONCLUSIONS: This study demonstrates that EuroSCORE II is a good predictor of hospital mortality after cardiac surgery in an external validation cohort of contemporary patients from a multicentre prospective regional registry. The EuroSCORE II predicts hospital mortality with a slight underestimation in high-risk patients that should be further and better evaluated. The EuroSCORE II variables as a risk tree provides clinicians and surgeons a practical bedside tool for mortality risk stratification of patients at low, intermediate and high risk for hospital mortality after cardiac surgery.

Lung regional stress and strain as a function of posture and ventilatory mode.

During positive-pressure ventilation parenchymal deformation can be assessed as strain (volume increase above functional residual capacity) in response to stress (transpulmonary pressure). The aim of this study was to explore the relationship between stress and strain on the regional level using computed tomography in anesthetized healthy pigs in two postures and two patterns of breathing. Airway opening and esophageal pressures were used to calculate stress; change of gas content as assessed from computed tomography was used to calculate strain. Static stress-strain curves and dynamic strain-time curves were constructed, the latter during the inspiratory phase of volume and pressure-controlled ventilation, both in supine and prone position. The lung was divided into nondependent, intermediate, dependent, and central regions: their curves were modeled by exponential regression and examined for statistically significant differences. In all the examined regions, there were strong but different exponential relations between stress and strain. During mechanical ventilation, the end-inspiratory strain was higher in the dependent than in the nondependent regions. No differences between volume- and pressure-controlled ventilation were found. However, during volume control ventilation, prone positioning decreased the end-inspiratory strain of dependent regions and increased it in nondependent regions, resulting in reduced strain gradient. Strain is inhomogeneously distributed within the healthy lung. Prone positioning attenuates differences between dependent and nondependent regions. The regional effects of ventilatory mode and body positioning should be further explored in patients with acute lung injury.

Emergence times are similar with sevoflurane and total intravenous anesthesia: results of a multicenter RCT of patients scheduled for elective supratentorial craniotomy.

BACKGROUND: Nearly every anesthetic agent has been used for craniotomy, yet the choice between intravenous or volatile agents has been considered an area of significant debate in neuroanesthesia. We designed a Randomized Clinical Trial to test the hypothesis that inhalation anesthesia (sevoflurane/remifentanil--group S) reduces emergence time by 5 minutes compared with intravenous anesthesia (propofol/remifentanil--group P) in patients undergoing neurosurgery for supratentorial neoplasms. METHODS: Adult ASA I-III elective patients were randomly assigned to group S or P. The primary outcome was time to reach an Aldrete test score (AS) of more than equal to 9; secondary outcomes were times to eyes opening (TEO) and extubation (ET), adverse events, intraoperative hemodynamics, brain relaxation score (BRS), opioid consumption, and diuresis. RESULTS: No significant differences were found between S (n=149) and P (n=153) treatments in primary outcomes: median time to reach AS=9 was 5 minutes (25th to 75th percentile 5 to 10 minutes in both groups, P > or = 0.05); and 15 minutes to reach AS=10 (P group 95% CI=10.3-19.7 min; S group 95% CI=11.4-18.5 min, P > or = 0.05) in both groups. TEO and ET expressed as median values (95% CI) were, respectively: 8 (6.8 to 9.2) minutes in group P versus 6 (4.6 to 7.4) in group S, P < 0.05; 10 (9.6 to 10.4) minutes in group P versus 8 (7 to 9) in group S, P < 0.05. Shivering, postoperative nausea and vomiting, pain, and seizure during the first 3 postoperative hours were not significantly different between the 2 groups, nor was BRS. Hypotension was more frequent in group S. Intraoperative diuresis and opioid consumption were greater in group P. CONCLUSIONS: Sevoflurane/remifentanil neuroanesthesia is not superior to propofol/remifentanil in time to reach an AS > or = 9.

Melatonin protects against heart ischemia-reperfusion injury by inhibiting mitochondrial permeability transition pore opening.

Melatonin, a well-known antioxidant, has been shown to protect against ischemia-reperfusion myocardial damage. Mitochondrial permeability transition pore (MPTP) opening is an important event in cardiomyocyte cell death occurring during ischemia-reperfusion and therefore a possible target for cardioprotection. In the present study, we tested the hypothesis that melatonin could protect heart against ischemia-reperfusion injury by inhibiting MPTP opening. Isolated perfused rat hearts were subjected to global ischemia and reperfusion in the presence or absence of melatonin in a Langerdoff apparatus. Melatonin treatment significantly improves the functional recovery of Langerdoff hearts on reperfusion, reduces the infarct size, and decreases necrotic damage as shown by the reduced release of lactate dehydrogenase. Mitochondria isolated from melatonin-treated hearts are less sensitive than mitochondria from reperfused hearts to MPTP opening as demonstrated by their higher resistance to Ca(2+). Similar results were obtained following treatment of ischemic-reperfused rat heart with cyclosporine A, a known inhibitor of MPTP opening. In addition, melatonin prevents mitochondrial NAD(+) release and mitochondrial cytochrome c release and, as previously shown, cardiolipin oxidation associated with ischemia-reperfusion. Together, these results demonstrate that melatonin protects heart from reperfusion injury by inhibiting MPTP opening, probably via prevention of cardiolipin peroxidation.

Inhomogeneity of lung parenchyma during the open lung strategy: a computed tomography scan study.

RATIONALE: The open lung strategy aims at reopening (recruitment) of nonaerated lung areas in patients with acute respiratory distress syndrome, avoiding tidal alveolar hyperinflation in the limited area of normally aerated tissue (baby lung). OBJECTIVES: We tested the hypothesis that recruited lung areas do not resume elastic properties of adjacent baby lung. METHODS: Twenty-five anesthetized, mechanically ventilated pigs were studied. Four lung-healthy pigs served as controls and the remaining 21 were divided into three groups (n = 7 each) in which lung injury was produced by surfactant lavage, lipopolysaccharide infusion, or hydrochloride inhalation. Computed tomography scans, respiratory mechanics, and gas exchange parameters were recorded under three conditions: at baseline, during lung recruitment maneuver, and at end-expiration and end-inspiration when ventilating after an open lung protocol. MEASUREMENTS AND MAIN RESULTS: During recruitment maneuver and open lung protocol, the gas volume entering the insufficiently aerated compartment was 96% (75-117%) and 48% (41-63%) (median [interquartile range]) of the functional residual capacity measured before and at zero end-expiratory pressure, respectively. Nonetheless, the volume of hyperinflated lung increased during both recruitment maneuver (by 1-28% of total lung volume; P < 0.01) and open lung protocol ventilation at end-inspiration (by 1-15% of total lung volume; P < 0.01). Regional elastance of recruited lung tissue was consistently higher than that of the baby lung regardless of the ARDS model (P < 0.01). CONCLUSIONS: Alveolar recruitment is not protective against hyperinflation of the baby lung because lung parenchyma is inhomogeneous during ventilation with the open lung strategy.

Does perioperative hemodynamic optimization protect renal function in surgical patients? A meta-analytic study.

OBJECTIVE: Postoperative acute deterioration in renal function, producing oliguria and/or increase in serum creatinine, is one of the most serious complication in surgical patients. Most cases are due to renal hypoperfusion as a consequence of systemic hypotension, hypovolemia, and cardiac dysfunction. Although some evidence suggests that perioperative monitoring and manipulation of oxygen delivery by volume expansion and inotropic drugs may decrease mortality in surgical patients, no study analyzed this approach on postoperative renal dysfunction. The objective of this investigation is to perform a meta-analysis on the effects of perioperative hemodynamic optimization on postoperative renal dysfunction. DATA SOURCES, STUDY SELECTION, DATA EXTRACTION: A systematic literature review, using MEDLINE, EMBASE, and The Cochrane Library databases through January 2008 was conducted and 20 studies met the inclusion criteria (4220 participants). Data synthesis was obtained by using odds ratio (OR) with 95% confidence interval (CI) by random-effects model. DATA SYNTHESIS: Postoperative acute renal injury was significantly reduced by perioperative hemodynamic optimization when compared with control group (OR 0.64; CI 0.50-0.83; p = 0.0007). Perioperative optimization was effective in reducing renal injury defined consistently with risk, injury, failure, and loss and end-stage kidney disease and Acute Kidney Injury Network classifications, and in studies defining renal dysfunction by serum creatinine and/or need of renal replacement therapy only (OR 0.66; CI 0.50-0.88; p = 0.004). The occurrence of renal dysfunction was reduced when treatment started both preoperatively and intraoperatively or postoperatively, was performed in high-risk patients, and was obtained by fluids and inotropes. Mortality was significantly reduced in treatment group (OR 0.50; CI 0.31-0.80; p = 0.004), but statistical heterogeneity was observed. CONCLUSIONS: Surgical patients receiving perioperative hemodynamic optimization are at decreased risk of renal impairment. Because of the impact of postoperative renal complications on adverse outcome, efforts should be aimed to identify patients and surgery that would most benefit from perioperative optimization.

Pulmonary atelectasis during low stretch ventilation: "open lung" versus "lung rest" strategy.

OBJECTIVE: Limiting tidal volume (VT) may minimize ventilator-induced lung injury (VILI). However, atelectasis induced by low VT ventilation may cause ultrastructural evidence of cell disruption. Apoptosis seems to be involved as protective mechanisms from VILI through the involvement of mitogen-activated protein kinases (MAPKs). We examined the hypothesis that atelectasis may influence the response to protective ventilation through MAPKs. DESIGN: Prospective randomized study. SETTING: University animal laboratory. SUBJECTS: Adult male 129/Sv mice. INTERVENTIONS: Isolated, nonperfused lungs were randomized to VILI: VT of 20 mL/kg and positive end-expiratory pressure (PEEP) zero; low stretch/lung rest: VT of 6 mL/kg and 8-10 cm H2O of PEEP; low stretch/open lung: VT of 6 mL/kg, two recruitment maneuvers and 14-16 cm H2O of PEEP. Ventilator settings were adjusted using the stress index. MEASUREMENT AND MAIN RESULT: Both low stretch strategies equally blunted the VILI-induced derangement of respiratory mechanics (static volume-pressure curve), lung histology (hematoxylin and eosin), and inflammatory mediators (interleukin-6, macrophage inflammatory protein-2 [enzyme-linked immunosorbent assay], and inhibitor of nuclear factor-kB[Western blot]). VILI caused nuclear swelling and membrane disruption of pulmonary cells (electron microscopy). Few pulmonary cells with chromatin condensation and fragmentation were seen during both low stretch strategies. However, although cell thickness during low stretch/open lung was uniform, low stretch/lung rest demonstrated thickening of epithelial cells and plasma membrane bleb formation. Compared with the low stretch/open lung, low stretch/lung rest caused a significant decrease in apoptotic cells (terminal deoxynucleotidyl transferase mediated deoxyuridine-triphosphatase nick end-labeling) and tissue expression of caspase-3 (Western blot). Both low stretch strategies attenuated the activation of MAPKs. Such reduction was larger during low stretch/open lung than during low stretch/lung rest (p < 0.001). CONCLUSION: Low stretch strategies provide similar attenuation of VILI. However, low stretch/lung rest strategy is associated to less apoptosis and more ultrastructural evidence of cell damage possibly through MAPKs-mediated pathway.

Antithrombin after cardiac surgery: implications on short and mid-term outcome.

BACKGROUND: Antithrombin (AT) drop during cardiac surgery has been described. The causes and the effects of this phenomenon are not clear. The objective of the study is to evaluate the relationship of AT postoperative values on short and mid-term outcome after cardiac surgery. METHODS: Between January and June 2005, 405 patients, who underwent cardiac operations at our Institution had AT values available preoperatively and postoperatively. Using Receiver Operating Characteristic curves, a cut-off equal to 63.7% for ICU-arrival AT was chosen in order to divide the entire population in two groups (117 patients with ICU-arrival AT < 63.7%, Low AT group, and 288 patients with ICU-arrival AT > or = 63.7%, High AT group). Objective of the study was to evaluate the predictive role of ICU-arrival AT < 63.7% on in-hospital mortality and morbidity and on 18 months follow-up after cardiac surgery. RESULTS: ICU-arrival AT was significantly lower than preoperative AT (90.7 +/- 16.3% vs. 71.2 +/- 15.1%, P < 0.0001). Patients in the Low AT group were older, more often female, had a worse Euroscore and required longer CPB duration and cross clamp time. They had significantly higher preoperative and postoperative D-dimer levels. ICU arrival AT < 63.7% was not associated with increased in-hospital mortality but it was an independent risk factor for longer mechanical ventilation, need of inotropic support, excessive bleeding and blood products transfusion. ICU arrival-AT < 63.7% was associated with worse survival during 18 months follow up (92.3% vs. 85.4% in the High AT and Low AT group, respectively, P = 0.05). CONCLUSIONS: Low AT after cardiac surgery is associated with higher incidences of peri-operative complications and worse survival in the mid-term. Future studies should clarify the pathophysiologic mechanism of this findings and possible therapeutic directions.

Hyperoxia confers myocardial protection in mechanically ventilated rats through the generation of free radicals and opening of mitochondrial ATP-sensitive potassium channels.

1. One hour exposure to hyperoxia has been shown previously to limit a subsequent ischaemia-reperfusion injury in spontaneously breathing rats. We tested the cardioprotective effect of a shorter period of hyperoxia during mechanical ventilation and the possible contribution of reactive oxygen species (ROS) and mitochondrial ATP-sensitive potassium (mitoK(ATP)) channels. 2. Mechanically ventilated rats were exposed to normoxia (Fi O2 = 0.3) or hyperoxia (Fi O2 = 1.0) for 30 min and pH, P CO2, PO2, heart rate, airway and blood pressure were measured at baseline and after 30 min mechanical ventilation. Isolated hearts were subsequently subjected to 30 min ischaemia and 120 min reperfusion. Infarct size and left ventricular end-diastolic pressure (LVEDP), developed pressure (LVDP) and coronary flow (CF) were measured. In order to investigate the role of ROS and KATP channels within the mechanism leading to cardioprotection, the free radical scavenger N-acetylcysteine (NAC; 150 mg/kg) was infused in mechanically ventilated rats and the KATP channel blockers glibenclamide (200 mmol/L) or 5-hydroxydecanoate (10 mmol/L) were infused in isolated hearts immediately before ischaemia. 3. No differences were detected in P CO2, pH, heart rate, airway and blood pressure between the groups. However, the PO2 in hyperoxic groups was significantly higher compared with that in normoxic groups (P < 0.01). After 30 min ischaemia, we found that hyperoxic preconditioning significantly improved CF (P < 0.01), LVDP (P < 0.01) and LVEDP (P < 0.01) and reduced the extent of infarct size in the reperfused heart compared with the normoxic group (P < 0.01). When rats were pretreated either with NAC before hyperoxic ventilation or with K(ATP) channel blockers before ischaemia, myocardial protection was abolished. 4. Hyperoxic mechanical ventilation, prior to ischaemia, reduces myocardial reperfusion injury. This is likely to occur through the induction of oxidative stress, which leads to myocyte mitoKATP channel opening.

ARDSnet ventilatory protocol and alveolar hyperinflation: role of positive end-expiratory pressure.

RATIONALE: In patients with acute respiratory distress syndrome (ARDS), a focal distribution of loss of aeration in lung computed tomography predicts low potential for alveolar recruitment and susceptibility to alveolar hyperinflation with high levels of positive end-expiratory pressure (PEEP). OBJECTIVES: We tested the hypothesis that, in this cohort of patients, the table-based PEEP setting criteria of the National Heart, Lung, and Blood Institute's ARDS Network (ARDSnet) low tidal volume ventilatory protocol could induce tidal alveolar hyperinflation. METHODS: In 15 patients, physiologic parameters and plasma inflammatory mediators were measured during two ventilatory strategies, applied randomly: the ARDSnet and the stress index strategy. The latter used the same ARDSnet ventilatory pattern except for the PEEP level, which was adjusted based on the stress index, a monitoring tool intended to quantify tidal alveolar hyperinflation and/or recruiting/derecruiting that occurs during constant-flow ventilation, on a breath-by-breath basis. MEASUREMENTS AND MAIN RESULTS: In all patients, the stress index revealed alveolar hyperinflation during application of the ARDSnet strategy, and consequently, PEEP was significantly decreased (P < 0.01) to normalize the stress index value. Static lung elastance (P = 0.01), plasma concentrations of interleukin-6 (P < 0.01), interleukin-8 (P = 0.031), and soluble tumor necrosis factor receptor I (P = 0.013) were significantly lower during the stress index as compared with the ARDSnet strategy-guided ventilation. CONCLUSIONS: Alveolar hyperinflation in patients with focal ARDS ventilated with the ARDSnet protocol is attenuated by a physiologic approach to PEEP setting based on the stress index measurement.

Patient-requested neuraxial analgesia for labor: impact on rates of cesarean and instrumental vaginal delivery.

A systematic review, including a meta-analysis, on the timing effects of neuraxial analgesia (NA) on cesarean and instrumental vaginal deliveries in nulliparous women was conducted. Of 20 articles identified, 9 met the inclusion quality criteria (3,320 participants). Cesarean delivery (odds ratio, 1.00; 95% confidence interval, 0.82-1.23) and instrumental vaginal delivery (odds ratio, 1.00; 95% confidence interval, 0.83-1.21) rates were similar in the early NA and control groups. Neonates of women with early NA had a higher umbilical artery pH and received less naloxone. In the early NA group, fewer women were not compliant with assigned treatment and crossed over to the control group. Women receiving early NA for pain relief are not at increased risk of operative delivery, whereas those receiving early parenteral opioid and late epidural analgesia present a higher risk of instrumental vaginal delivery for nonreassuring fetal status, worse indices of neonatal wellness, and a lower quality of maternal analgesia.

Use of N-terminal pro-brain natriuretic peptide to detect acute cardiac dysfunction during weaning failure in difficult-to-wean patients with chronic obstructive pulmonary disease.

OBJECTIVE: To evaluate the utility of serial measurements of plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) to detect acute cardiac dysfunction during weaning failure in difficult to wean patients with chronic obstructive pulmonary disease. DESIGN: Prospective observational cohort study. SETTING: A 14-bed general intensive care unit in a university hospital. PATIENTS: Nineteen patients mechanically ventilated for chronic obstructive pulmonary disease exacerbation who were difficult to wean. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Cardiac and hemodynamic variables, arterial and central venous blood gas, breathing pattern, respiratory mechanics, indexes of oxygen cost of breathing, and plasma levels of NT-proBNP were measured and analyzed immediately before (baseline) and at the end of a spontaneous breathing trial. Eight of 19 patients (42%) were identified with acute cardiac dysfunction at the end of the weaning trial. Baseline NT-proBNP levels were significantly higher (median 5000, interquartile range 4218 pg/mL) in these patients than in patients without evidence of acute cardiac dysfunction (median 1705, interquartile range 3491 pg/mL). Plasma levels of NT-proBNP increased significantly at the end of the spontaneous breathing trial only in patients with acute cardiac dysfunction (median 12,733, interquartile range 16,456 pg/mL, p < .05). The elevation in NT-proBNP at the end of the weaning trial had a good diagnostic performance in detecting acute cardiac dysfunction, as estimated by area under the receiver operating characteristic curve analysis (area under the curve 0.909, se 0.077, 95% confidence interval 0.69-0.98; p < .0001, cutoff = 184.7 pg/mL). CONCLUSIONS: Serial measurements of NT-proBNP plasma levels provided a noninvasive manner to detect acute cardiac dysfunction during an unsuccessful weaning trial in difficult to wean patients with chronic obstructive pulmonary disease. The utility of this test as a complement of the standard clinical monitoring of the weaning trial deserves further investigation.

Superior mesenteric artery blood flow modifications during off-pump coronary surgery.

BACKGROUND: Patients undergoing cardiac surgery are at increased risk of gut hypoperfusion. During off-pump surgery, hemodynamic derangements at the time of heart displacement could reduce splanchnic perfusion, outweighing the beneficial effects of avoiding cardiopulmonary bypass. The purpose of this study is to assess, prospectively, blood flow modifications in the superior mesenteric artery during off-pump surgery using transesophageal echocardiography. METHODS: In 19 patients undergoing multivessel elective off-pump coronary revascularization, systemic hemodynamics and superior mesenteric flow were assessed. Blood flow in the superior mesenteric artery was evaluated with duplex ultrasound using a transesophageal echo probe. Measurements were made four times: T0 (baseline), T1 (left anterior descendent anastomosis), T2 (heart displacement to expose the inferolateral and inferior walls), and T3 (closed chest, at the end of surgery). RESULTS: Superior mesenteric blood flow significantly decreased at T2 (from 426.4 +/- 83.1 mL to 212.9 +/- 48.6 mL, p < 0.001), when also cardiac output was reduced. The percentage of the cardiac output directed toward the mesenteric arterial bed was also decreased at this time. At the end of surgery (T3), whereas cardiac output returned to the initial values, mesenteric flow was significantly increased compared with baseline, with a higher percentage of the systemic output flowing through the superior mesenteric artery. CONCLUSIONS: Hemodynamic changes during off-pump coronary surgery induce a significant mesenteric hypoperfusion followed by a hyperemic response at the end of surgery. Transesophageal echo-Doppler allows the intraoperative measurement of blood flow distribution to splanchnic viscera.

A comparison between fenoldopam and low-dose dopamine in early renal dysfunction of critically ill patients.

OBJECTIVE: Fenoldopam mesylate is a selective dopamine-1 agonist, with no effect on dopamine-2 and alpha1 receptors, producing a selective renal vasodilation. This may favor the kidney oxygen supply/demand ratio and prevent acute renal failure. The aim of the study was to investigate if fenoldopam can provide greater benefit than low-dose dopamine in early renal dysfunction of critically ill patients. DESIGN: Prospective, multiple-center, randomized, controlled trial. SETTING: University and city hospital intensive care units. PATIENTS: One hundred adult critically ill patients with early renal dysfunction (intensive care unit stay<1 wk, hemodynamic stability, and urine outputor=1.5 mg/dL and10% of the baseline value at the end of infusion, compared with only 46% in dopamine group (chi-square=4.06, p=.04). Total urinary output during drug infusion was not significantly different between groups. After 1 day, urinary output was lower in group F compared with group D (p<.05). CONCLUSIONS: In critically ill patients, a continuous infusion of fenoldopam at 0.1 microg/kg/min does not cause any clinically significant hemodynamic impairment and improves renal function compared with renal dose dopamine. In the setting of acute early renal dysfunction, before severe renal failure has occurred, the attempt to reverse renal hypoperfusion with fenoldopam is more effective than with low-dose dopamine.

Jaundice in critical illness: promoting factors of a concealed reality.

OBJECTIVE: In critical illness, liver dysfunction (LD) is associated with a poor outcome independently of other organ dysfunctions. Since strategies to support liver function are not available, a timely and accurate identification of factors promoting LD may lead to prevention or attenuation of its consequences. The aim of this study was to assess risk factors for LD in critically ill patients. DESIGN: Prospective, observational study. SETTING: A multidisciplinary intensive care unit (ICU) of a university hospital. PATIENTS: All patients consecutively admitted over a 6-month period. INTERVENTION: None. MEASUREMENTS AND RESULTS: LD was defined as serum bilirubin levels >or=2 mg/dl and lasting for at least 48 h. Out of 283 patients, 141 matched inclusion criteria. Forty-four patients (31.2%) showed LD (LD group), while 97 (68.8%) were included in control group (C group). A binomial analysis showed that LD occurrence was associated with moderate (odds ratio [OR] 3.11; p=0.04) and severe shock (OR 3.46; p= 0.05), sepsis (OR 3.03; p=0.04), PEEP ventilation (OR 4.25; p=0.006), major surgery (OR 4.03; p=0.03), and gram-negative infections (OR 3.94; p=0.002). In stepwise multivariate analysis, the single independent predictive factors of LD resulted in severe shock (p=0.002), sepsis (p=0.03), PEEP ventilation (p=0.04), and major surgery (p=0.05). CONCLUSIONS: In critically ill patients jaundice is common, and severe shock states, sepsis, mechanical ventilation with PEEP and major surgery are critical risk factors for its onset. Since there is no specific treatment, prompt resuscitation, treatment of sepsis and meticulous supportive care will likely reduce its incidence and severity.