Heart rate reduction with esmolol is associated with improved arterial elastance in patients with septic shock: a prospective observational study.

PURPOSE: Ventricular-arterial (V-A) decoupling decreases myocardial efficiency and is exacerbated by tachycardia that increases static arterial elastance (Ea). We thus investigated the effects of heart rate (HR) reduction on Ea in septic shock patients using the beta-blocker esmolol. We hypothesized that esmolol improves Ea by positively affecting the tone of arterial vessels and their responsiveness to HR-related changes in stroke volume (SV). METHODS: After at least 24 h of hemodynamic optimization, 45 septic shock patients, with an HR ≥95 bpm and requiring norepinephrine to maintain mean arterial pressure (MAP) ≥65 mmHg, received a titrated esmolol infusion to maintain HR between 80 and 94 bpm. Ea was calculated as MAP/SV. All measurements, including data from right heart catheterization, echocardiography, arterial waveform analysis, and norepinephrine requirements, were obtained at baseline and at 4 h after commencing esmolol. RESULTS: Esmolol reduced HR in all patients and this was associated with a decrease in Ea (2.19 ± 0.77 vs. 1.72 ± 0.52 mmHg l(-1)), arterial dP/dt max (1.08 ± 0.32 vs. 0.89 ± 0.29 mmHg ms(-1)), and a parallel increase in SV (48 ± 14 vs. 59 ± 18 ml), all p < 0.05. Cardiac output and ejection fraction remained unchanged, whereas norepinephrine requirements were reduced (0.7 ± 0.7 to 0.58 ± 0.5 µg kg(-1) min(-1), p < 0.05). CONCLUSIONS: HR reduction with esmolol effectively improved Ea while allowing adequate systemic perfusion in patients with severe septic shock who remained tachycardic despite standard volume resuscitation. As Ea is a major determinant of V-A coupling, its reduction may contribute to improving cardiovascular efficiency in septic shock.

Non-invasive ventilation in patients with hematologic malignancy: a new prospective.

Immunosuppressed patients are usually considered together without distinction. However, patients with hematologic malignancy should be included in a different subcategory. The outcome of this population has improved over the years. However, mortality rate continues to be high, especially when respiratory complications are present and mechanical ventilation is required. Non-invasive ventilation (NIV) demonstrated its efficacy on the process of respiratory failure improving clinical outcomes in patients of different diagnoses. Recommendations of guidelines to use NIV in immunosuppressed patients have been quite prudent. However, NIV has been recently applied in hematologic malignancy patients during an early or/and late respiratory failure, showing a favorable impact improving the outcome. At an early stage, one study showed CPAP to reduce respiratory complications and to improve the outcome of mortality rate from 75% in the control group to 15% in the treatment group, when compared to oxygen therapy. In other two randomized control trials, NIV in comparison to invasive mechanical ventilation demonstrated to reduce mortality rate from 100% to 53-61%. As most of the non-randomized control trials applied NIV in a general population of immunosuppressed patients, results are very difficult to analyze. So far, the treatment starting, and duration time are still not clearly defined. Novel clinical trials should be performed to elucidate the appropriate application of NIV in this population.

Respiratory failure due to upper airway obstruction in children: use of the helmet as bridge interface.

Upper airway obstruction (UAO) can cause severe respiratory distress in young children by increasing inspiratory muscle load and decreasing alveolar ventilation, ultimately resulting in hypercapnia and hypoxemia which have long term negative cardiovascular effects. Although non-invasive continuous positive airway pressure (CPAP) improves gas exchange in these patients, use of conventional interfaces (nasal mask, nasal pillow and facial mask) may cause significant discomfort and lead to CPAP intolerance. We report five cases of children affected by UAO who experienced CPAP intolerance via application of conventional interfaces. Alternatively, we acutely applied helmet-CPAP which resulted in improved breathing pattern and gas exchange. Thereafter, patients received training with respect to a nasal CPAP interface, allowing successful long term treatment. In conclusion, these five clinical cases demonstrate that helmet-CPAP can be used acutely in children with UAO if compliance to conventional modalities is problematic, allowing for sufficient time to achieve compliance to nasal-CPAP.

Temporal relationship between endothelin-1 concentrations and cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Endothelin 1 (ET-1) is a potent vasoconstrictor that may play a role in cerebral vasospasm following subarachnoid hemorrhage (SAH). However, data regarding its pathogenic role in the development of vasospasm are controversial. We planned a prospective, observational clinical study to investigate the temporal relationship between increased ET-1 production and cerebral vasospasm or other neurological sequelae after SAH. METHODS: ET-1 levels in cerebrospinal fluid (CSF) were measured in 20 SAH patients from admission (within 24 hours from the bleeding) until day 7. Patients received a daily transcranial Doppler study and a neurological evaluation. On day 7, angiography was performed to verify the degree and extent of vasospasm. Patients were then classified as having (1) clinical vasospasm, (2) angiographic vasospasm, (3) no vasospasm, or (4) poor neurological condition without significant vasospasm (low Glasgow Coma Scale score [GCS]). RESULTS: On admission, ET-1 levels were increased in the low-GCS group compared with the other groups (P=0.04). On day 4 ET-1 levels were not significantly different among groups, whereas on day 7 ET-1 levels were significantly increased in both the clinical vasospasm and low-GCS groups compared with the angiographic vasospasm and no vasospasm groups (P<0.005). Moreover, when the low-GCS group was excluded, there was a significant relationship between vasospasm grade and CSF ET-1 levels (R(2)=0.73). CONCLUSIONS: CSF ET-1 levels were markedly elevated in patients with clinical manifestations of vasospasm (day 7) and with a poor neurological condition not related to vasospasm. However, ET-1 levels were low in clinical vasospasm patients before clinical symptoms were evident (day 4) and remained low in angiographic vasospasm patients throughout the study period. Thus, our data suggest that CSF ET-1 levels are increased in conditions of severe neuronal damage regardless whether this was due to vasospasm or to the primary hemorrhagic event. In addition, CSF ET-1 levels paralleled the neurological deterioration but were not predictive of vasospasm.

Continuous positive airway pressure facilitates spontaneous breathing in weaning chronic obstructive pulmonary disease patients by improving breathing pattern and gas exchange.

OBJECTIVE: To elucidate the effects of continuous positive airway pressure (CPAP) on breathing pattern, gas exchange and the ability to sustain spontaneous breathing (SB) in chronic obstructive pulmonary disease (COPD) patients with dynamic hyperinflation. DESIGN: Prospective study with two randomised trials of SB without and with CPAP in each patient. SETTING: Medical intensive care units (ICUs) in two university hospitals. PATIENTS: Nine dynamically hyperinflated, intubated COPD patients recuperating from acute exacerbation. INTERVENTIONS: One SB trial with CPAP (5-7.5 cmH2O), one without (control) in each patient. MEASUREMENTS: airway opening pressure, gas flow and thus breathing pattern, oxygen uptake, carbon dioxide excretion, arterial blood gases, dyspnoea and respiratory drive (P100). RESULTS: With CPAP, intrinsic positive end-expiratory pressure (PEEPi) fell from 11.4 to 6.3 cm H2O (p < 0.05). Eight patients sustained SB with CPAP for the maximum time planned (30 min), one failed after 18 min. In contrast, only four patients successfully completed the control trial, the others failing after 5-18 min (p < 0.05). Dyspnoea-gauged on a visual analogue scale by five patients--was less severe or occurred later with CPAP. Breathing with CPAP tended to be slower (18.9 vs 22.2 min(-1), p < 0.05) and deeper (tidal volume 370 vs 323 ml). At the end of the control run, PaCO2 was higher (60 vs 55 mmHg, p < 0.05) and still rising while being stable at the end of the CPAP trial. CONCLUSION: CPAP helps severely ill COPD patients sustain SB. Apparently it does so by promoting slower, deeper breathing and thus facilitating carbon dioxide elimination.

The accuracy of transcranial Doppler to detect vasospasm in patients with aneurysmal subarachnoid hemorrhage.

OBJECTIVES: To examine the accuracy of transcranial Doppler to detect cerebral vasospasm in a patient population with aneurysmal subarachnoid hemorrhage. DESIGN: Prospective blind comparison of transcranial Doppler with cerebral angiography. Diagnostic accuracy of transcranial Doppler was assessed using receiver operating characteristic (ROC) analysis and likelihood ratios. Sensitivity and specificity were calculated using directly measured middle cerebral artery diameter as reference standard. SETTING: Intensive Care Unit of a large university teaching hospital. PATIENTS AND PARTICIPANTS: Twenty-two patients with subarachnoid hemorrhage were included. Patients underwent angiography on admission and after 8 days to diagnose vasospasm and were defined as having clinical vasospasm, angiographic vasospasm, or no vasospasm. MEASUREMENTS AND RESULTS: Sensitivity and specificity were 1.00 and 0.75 for angiographic vasospasm and both equal to 1.00 for clinical vasospasm diagnosis. A transcranial Doppler mean velocity threshold value of 100 cm/s for angiographic vasospasm and 160 cm/s for clinical vasospasm detection were chosen by ROC analysis. CONCLUSIONS: A Transcranial Doppler mean velocity threshold of 160 cm/s, calculated by the ROC analysis, accurately detects clinical vasospasm. A daily transcranial Doppler examination performed by a trained operator should be routinely used to provide early identification of patients at high risk and to orient therapeutic decisions.

Inspiratory effort and measurement of dynamic intrinsic PEEP in COPD patients: effects of ventilator triggering systems.

OBJECTIVE: To investigate effects of ventilator triggering systems (pressure and flow triggering: PT and FT) on measurement of dynamic intrinsic PEEP (PEEPidyn) and patient-ventilator interaction in patients with chronic obstructive pulmonary disease during weaning from mechanical ventilation. DESIGN: Prospective study. SETTING: Medical/surgical intensive care unit of an academic hospital. PATIENTS AND PARTICIPANTS: 6 COPD patients with acute respiratory failure ready to wean. MEASUREMENTS: We measured flow, airway opening, esophageal and gastric pressures. Minute ventilation, breathing pattern and pressure time product (PTP) of the respiratory muscles and of the diaphragm were obtained during spontaneous ventilation through a mechanical ventilator (Puritan-Bennett 7200ae). Two triggering systems, namely PT and FT, were evaluated. RESULTS: The inspiratory muscles effort necessary to overcome the triggering system overestimated PEEPidyn measurement of an amount equal to 49 +/- 2 and 58 +/- 3% during respectively pressure and flow triggering. FT increased tidal volume and minute ventilation and decrease PTP/b and PTP/min of the respiratory muscles and diaphragm. CONCLUSIONS: To correctly measure PEEPidyn, the inspiratory effort produced to overcome PEEPi and to trigger the ventilator must be discriminated. Application of flow triggering requires less effort to initiate inspiration and provide a positive end-expiratory pressure level that is able to unload the respiratory muscles by reducing PEEPi. With flow triggering higher minute ventilation are obtained in COPD patients during the weaning phase.

Effects of positive end-expiratory pressure on right ventricular function in COPD patients during acute ventilatory failure.

OBJECTIVE: To examine the effects of external positive end-expiratory pressure (PEEP) on right ventricular function in chronic obstructive pulmonary disease (COPD) patients with intrinsic PEEP (PEEPi). DESIGN: Prospective study. SETTING: General intensive care unit in a university teaching hospital. PATIENTS: Seven mechanically ventilated flow-limited COPD patients (PEEPi = 9.7 +/- 1.3 cmH2O, mean +/- SD) with acute respiratory failure. INTERVENTION: Hemodynamic and respiratory mechanic data were collected at four different levels of PEEP (0-5-10-15 cmH2O). MEASUREMENTS AND RESULTS: Hemodynamic parameters were obtained by a Swan-Ganz catheter with a fast response thermistor. Cardiac index (CI) and end-expiratory lung volume (EELV) reductions started simultaneously when the applied PEEP was approximately 90% of PEEPi measured on 0 cmH2O (ZEEP). Changes in transmural intrathoracic pressure (PEEPi,cw) started only at a PEEP value much higher (120%) than PEEPi. The reduction in CI was related to a decrease in the right end-diastolic ventricular volume index (RVEDVI) (r = 0.61; p < 0.001). No correlation between CI and transmural right atrial pressure was observed. The RVEDVI was inversely correlated with PEEP-induced changes in EELV (r = -55; p < 0.001), but no with PEEPi,cw (r = -0.08; NS). The relationship between RVEDVI and right ventricular stroke work index, considered an index of contractility, was significant in three patients, i.e., PEEP did not change contractility. In the other patients, an increase in contractility seemed to occur. CONCLUSIONS: In COPD patients an external PEEP exceeding 90% of PEEPi causes lung hyperinflation and reduces the CI due to a preload effect. The reduction in RVEDVI seems related to changes in EELV, rather than to changes in transmural pressures, suggesting a lung/heart volume interaction in the cardiac fossa. Thus, in COPD patients, application of an external PEEP level lower than PEEPi may affect right ventricular function.

Liver inflammation and acute respiratory distress syndrome in a patient receiving hepatitis B vaccine: a possible relationship?

We describe a patient in whom clinical evidence of liver and lung dysfunction developed after he received the second dose of recombinant hepatitis B vaccine, despite no serologic evidence of viral hepatitis. However, liver biopsy specimens demonstrated both surface antigens and core antigens, possibly indicating silent hepatitis B virus infection. A search for an infective etiology for the patient's subsequent clinical deterioration in lung function did not yield pathogens: postmortem examination revealed evidence of immune complex-mediated organ injury in the liver, lungs, and kidneys.

Right ventricular myocardial function in ARF patients. PEEP as a challenge for the right heart.

OBJECTIVE: To examine the hemodynamic effects of external positive end-expiratory pressure (PEEP) on right ventricular (RV) function in acute respiratory failure (ARF) patients. DESIGN: Prospective, with retrospective analysis on the basis of RV volume response to PEEP. SETTING: General intensive care unit in a university teaching hospital. PATIENTS: 20 mechanically ventilated ARF patients (mean lung injury score = 2.6 +/- 0.45 SD). INTERVENTION: Incremental levels of PEEP (0-5-10-15 cmH2O) were applied and RV hemodynamics were studied by means of a Swan-Ganz catheter with a fast-response thermistor for right ventricular ejection fraction (RVEF) measurement. According to their response to PEEP 15, two groups of patients were defined: group A (9 patients) with unchanged or increased RV end-diastolic volume index (RVEDVI) and group B (11 patients) with decreased RVEDVI. MEASUREMENTS AND RESULTS: At zero PEEP (ZEEP) the hemodynamic parameters of the two groups did not differ. In group A, cardiac index (CI) and stroke volume index (SI) decreased at all PEEP levels (5, 10, and 15 cmH2O), while RVEF started to decrease only at a PEEP of 10 cmH2O (-10.8%), and RVES(systolic)VI increased only at PEEP 15 cmH2O (+21.5%). RVEDVI was not affected by PEEP. In group B, CI and SI decreased at all PEEP levels (5, 10, and 15 cmH2O). Similarly, RVEDVI started to decrease at PEEP 5 cmH2O, while RVESVI decreased only at PEEP 15 cmH2O (-21.4%). RVEF was not affected by PEEP in this group. In each patient the slope of the relationship between RVEDVI and right ventricular stroke work index (RVSWI), expressing RV myocardial performance, was studied. This relationship was significant (no change in RV contractility) in 8 of 11 patients in group B and in only 2 patients in group A. In 4 patients in group A, PEEP shifted the RVSWI/RVEDVI ratio rightward in the plot, indicating a decrease in RV myocardial performance in these patients. CONCLUSIONS: PEEP affects RV function in ARF patients. The decrease in cardiac output is more often associated with a preload decrease and no change in RV contractility. On the other hand, the finding of increased RV volumes with PEEP may be associated with a reduction in RV myocardial performance. Thus, these results suggest that assessment of RV function by PEEP and preload recruitable stroke work may disclose otherwise unpredictable alterations in RV function.

Effect of PEEP on the mechanics of the respiratory system in ARDS patients.

In patients with adult respiratory distress syndrome (ARDS) we studied the effect of positive end-expiratory pressure (PEEP) on respiratory mechanics. We used the technique of rapid airway occlusion during constant flow (V) inflation to partition the total respiratory system resistance (Rrs) into the interrupter resistance (Rint,rs) and the additional resistance (delta Rrs) due to viscoelastic pressure dissipations and time constant inequalities. We also measured static (Est,rs) and dynamic (Edyn,rs) elastance of the respiratory system. The procedure was carried out in nine ARDS patients at different inspiratory V and inflation volumes (delta V) at PEEP of 0, 5, 10, and 15 cmH2O. We found that during baseline ventilation (delta V = 0.7 liter and V = 1 l/s), Est,rs, Edyn,rs, and Rint,rs did not change significantly with PEEP, whereas delta Rrs and Rrs increased significantly only with PEEP of 15 cmH2O. The increase of delta Rrs and Rrs with PEEP was positively correlated with the concomitant changes in end-expiratory lung volume (P < 0.001). At all levels of PEEP, under iso-delta V conditions, delta Rrs decreased with increasing V, whereas at a fixed V, delta Rrs increased with increasing delta V. A four-parameter model of the respiratory system failed to fully describe respiratory dynamics in the ARDS patients, probably due to nonlinearities.

Analysis of behavior of the respiratory system in ARDS patients: effects of flow, volume, and time.

The effects of inspiratory flow (V) and inflation volume (delta V) on the mechanical properties of the respiratory system in eight ARDS patients were investigated using the technique of rapid airway occlusion during constant-flow inflation. We measured interrupter resistance (Rint,rs), which in humans represents airway resistance, the additional resistance (delta Rrs) due to viscoelastic pressure dissipations and time constant inequalities, and static (Est,rs) and dynamic (Edyn,rs) elastance. The results were compared with a previous study on 16 normal anesthetized paralyzed humans (D'Angelo et al. J. Appl. Physiol. 67: 2556-2564, 1989). We observed that 1) resistance and elastance were higher in ARDS patients; 2) with increasing V, Rint,rs and Est,rs did not change, delta Rrs decreased progressively, and Edyn,rs increased progressively; 3) with increasing delta V, Rint,rs decreased slightly, delta Rrs increased progressively, and Est,rs and Edyn,rs showed an initial decrease followed by a secondary increase noted only in the ARDS patients. The above findings could be explained in terms of a model incorporating a standard resistance in parallel with a standard elastance and a series spring-and-dashpot body that represents the stress adaptation units within the tissues of the respiratory system.

Patient-ventilator interaction during acute hypercapnia: pressure-support vs. proportional-assist ventilation.

The objective of this study was to compare patient-ventilator interaction during pressure-support ventilation (PSV) and proportional-assist ventilation (PAV) in the course of increased ventilatory requirement obtained by adding a dead space in 12 patients on weaning from mechanical ventilation. With PSV, the level of unloading was provided by setting the inspiratory pressure at 20 and 10 cmH2O, whereas with PAV the level of unloading was at 80 and 40% of the elastic and resistive load. Hypercapnia increased (P < 0.001) tidal swing of esophageal pressure and pressure-time product per breath at both levels of PSV and PAV. During PSV, application of dead space increased ventilation (VE) during PSV (67 +/- 4 and 145 +/- 5% during 20 and 10 cmH2O PSV, respectively, P < 0.001). This was due to a relevant increase in respiratory rate (48 +/- 4 and 103 +/- 5% during 20 and 10 cmH2O PSV, respectively, P < 0.001), whereas the increase in tidal volume (VT) played a small role (13 +/- 1 and 21 +/- 2% during 20 and 10 cmH2O PSV, respectively, P < 0.001). With PAV, the increase in VE consequent to hypercapnia (27 +/- 3 and 64 +/- 4% during 80 and 40% PAV, respectively, P < 0.001) was related to the increase in VT (32 +/- 1 and 66 +/- 2% during 80 and 40% PAV, respectively, P < 0.001), respiratory rate remaining unchanged. The increase in pressure-time product per minute and per liter consequent to acute hypercapnia and the sense of breathlessness were significantly (P < 0.001) higher during PSV than during PAV. Our data show that, after hypercapnic stimulation of the respiratory drive, the capability to increase VE through changes in VT modulated by variations in inspiratory muscle effort is preserved only during PAV; the compensatory strategy used to increase VE during PSV requires greater muscle effort and causes more pronounced patient discomfort than during PAV.

Auto-positive end-expiratory pressure and dynamic hyperinflation.

PEEP is indicated in patients with COPD only to unload the respiratory muscles from the auto-PEEP resulting from expiratory flow limitation. If auto-PEEP is not caused by flow limitation, application of PEEP will cause further hyperinflation, worsening respiratory mechanics, muscle activity, and hemodynamics. To assess the presence of expiratory flow limitation correctly, to measure auto-PEEP correctly, and to identify the maximal PEEP level to be used, measurements of flow and opening pressure must be obtained during a brief period of suspended respiratory muscle activity (obtained by sedation) with the patient's own breathing pattern reproduced accurately.

Oxygen delivery-consumption relationship in adult respiratory distress syndrome patients: the effects of sepsis.

The oxygen consumption-delivery relationship (VO2/DO2) was studied in 15 sedated paralyzed patients with the adult respiratory distress syndrome (ARDS) due to multiple trauma and in whom sepsis was absent. Different levels (0 to 15 cm H2O) of positive end-expiratory pressure (PEEP) were applied. Oxygen delivery was calculated from cardiac index (thermodilution technique) and arterial oxygen content measurements. Oxygen consumption was calculated using Fick's equation. Regression lines were obtained for each patient. Oxygen supply dependency was defined as a significant (P < .05) relationship between changes in VO2 and DO2 with PEEP. Results were compared with those obtained in 18 ARDS patients in whom ARDS was due to sepsis. In nonseptic ARDS patients no significant relationship between changes in VO2 and DO2 with PEEP was found within the experimental range of DO2 on zero end-expiratory pressure (ZEEP) (347 to 845 mL/min/m2). None of these patients had multiple organ system failure (MOSF), and 73% survived. In ARDS patients in whom sepsis was present, supply dependency was present only when DO2 on ZEEP ranged between 330 and 640 mL/min/m2. All these patients developed MOSF and died. When DO2 on ZEEP ranged between 686 and 951 mL/min/m2 in septic ARDS patients, the supply dependency phenomenon was absent and only three patients developed MOSF and died (70% survivors). In almost all patients PEEP reduced DO2 and therefore worsened O2 balance by either increasing O2 extraction ratio and approaching the critical threshold for supply dependency or dismissing DO2 from the range of non-supply dependency.

Survival despite almost complete fibrous obstruction of a Sorin tilting disc mitral prosthesis.

We report the case of a 40-year-old woman whose Sorin tilting disc mitral prosthesis was obstructed by fibrous overgrowth to the point of near occlusion. The unusual features of this case are that the patient survived reoperation and that her preoperative symptoms were mild despite an immobile disc and near occlusion of the valve. In most similar cases in the literature, preoperative symptoms have been acute and mortality has been high.

Proportional assist ventilation.

Partial ventilatory support techniques are intended for patients who are unable to maintain a normal alveolar ventilation, despite normal central control for respiration. Proportional assist ventilation (PAV) is a novel mode of partial ventilatory support in which the ventilator generates an instantaneous inspiratory pressure in proportion to the instantaneous effort of the patient. In theory, PAV should normalize the neuro-ventilatory coupling by making the ventilator an extension of patient's respiratory muscles, while leaving to the patient the entire control of all aspects of breathing. PAV, however, shares a common problem with the conventional partial ventilatory support modes. In mechanically ventilated patients, the respiratory system impedance may change over time. These changes may impair the good matching between ventilator output and patient's ventilatory demand and lead to patient-ventilator asynchrony. To take full advantage of PAV, the authors believe that PAV should continuously and automatically adapt to the respiratory system passive mechanics, assessed by continuous noninvasive measurement of total elastance and resistance.

Epidemiology and outcome of sepsis syndromes in Italian ICUs: a muticentre, observational cohort study in the region of Piedmont.

BACKGROUND: Sepsis is an important cause of mortality and morbidity in the intensive care unit (ICU). We performed a study to describe the epidemiology of sepsis syndromes in patients admitted to ICUs of the Piedmont region. METHODS: In this prospective, multicentre, observational study, all 3902 patients admitted to a network of 24 ICUs from 17 hospitals during a 180 day period (April 3-September 29, 2006) were included. Patients were followed from the first day of admission until death or ICU discharge. RESULTS: The incidence of sepsis during the ICU stay was 11.4% (N.=446), corresponding to an incidence of 25 cases/100,000 inhabitants/year; 141 (31.6%) patients had only sepsis, 160 patients had severe sepsis (35.9%) and 145 patients (32.5%) had septic shock In 227 patients (50.9%), sepsis was observed within 48 hours after admission to the ICU, and 219 patients (49.1%) developed ICU-acquired sepsis. The main sources of infection were the lungs, abdomen, and urinary tract. ICU mortality was higher (41.3 vs. 17.3%, P<0.0001) and the median ICU length of stay longer (15 vs. 2 days, P<0.0001) in patients with sepsis than in those without sepsis. The mortality rate increased with the severity of sepsis. ICU-acquired sepsis was associated with higher ICU mortality rates than sepsis occurring within 48 hours of ICU admission (49.8 vs. 33.0%, P<0.0001). CONCLUSION: Sepsis is a common occurrence in critically ill patients. Our data underscore the regional variability in the epidemiology and outcome of sepsis syndromes and may be useful to guide appropriate resource allocation.

Recommendations for anesthesia and perioperative management of patients with neuromuscular disorders.

Patients with neuromuscular disorders are at high risk of intraoperative and postoperative complications. General anesthesia in these patients may exacerbate respiratory and cardiovascular failure due to a marked sensitivity to several anesthetic drugs. Moreover, succinylcholine and halogenated agents can trigger life-threatening reactions, such as malignant hyperthermia, rhabdomyolysis and severe hyperkalemia. Therefore, regional anesthesia should be used whenever possible. If general anesthesia is unavoidable, special precautions must be taken. In particular, for patients at increased risk of respiratory complications (i.e., postoperative atelectasis, acute respiratory failure, nosocomial infections), noninvasive ventilation associated with aggressive airway clearance techniques can successfully treat upper airway obstruction, hypoventilation and airway secretion retention, avoiding prolonged intubation and tracheotomy. Anesthesia and perioperative management of patients with neuromuscular disorders are described in this article. To grade the strength of recommendations and the quality of evidence we adopted the GRADE approach. In case of low-quality evidence, these recommendations represent the collective opinion of the expert panel.

What's new in the "Berlin" definition of acute respiratory distress syndrome?

A valid operative definition for ARDS is essential for the appropriate institution of a standardized 'best-evidence' treatment and for the identification of subgroups of patients who may benefit from specific adjunctive interventions, as well as to assist with prognostication, resource allocation and the design of new research trials. Here, we will discuss some of the methodology used by the ARDS Definition Task Force to develop the new 'Berlin' definition of ARDS, briefly discussing the rationale for the divergence from the AECC definition. The Berlin definition improves on the predictive validity for mortality of the American-European Consensus Conference's (AECC) definition and clarifies both the conceptual model of ARDS and the definition criteria of the syndrome and of its spectrum of severity. This should facilitate case recognition and more consistent treatment strategies based on severity.