Massimo Antonelli

Risk factors for acute renal failure in trauma patients

ObjectiveTo elucidate the risk factors for the development of acute renal failure (ARF) in severe trauma.DesignProspective observational study.SettingA general intensive care unit (ICU) of a university hospital.PatientsA cohort of 153 consecutive trauma patients admitted to the ICU over a period of 30 months.ResultsForty-eight (31 %) patients developed ARF. They were older than the 105 patients without ARF (p=0.002), had a higher Injury Severity Score (ISS) (p>0.001), higher mortality (p>0.001), a more compromised neurological condition (p=0.007), and their arterial pressure at study entry was lower (p=0.0015). In the univariate analysis, the risk of ARF increased by age, ISS>17, the presence of hemoperitoneum, shock, hypotension, or bone fractures, rhabdomyolysis with creatine Phosphokinase (CPK)>10000 IU/1, presence of acute lung injury requiring mechanical ventilation, and Glasgow Coma Score>10. Sepsis and use of nephrotoxic agents were not associated with an increased risk of ARF. In the logistic model, the need for mechanical ventilation with a positive end-expiratory pressure>6 cm H2O, rhabdomyolysis with CPK>10000 IU/1, and hemoperitoneum were the three conditions most strongly associated with ARF.ConclusionsThe identified risk factors for post-traumatic acute renal failure may help the provision of future strategies.

Paralysis has no effect on chest wall and respiratory system mechanics of mechanically ventilated, sedated patients

ObjectiveTo evaluate the separate effects of sedation and paralysis on chest wall and respiratory system mechanics of mechanically ventilated, critically ill patients.Setting: ICU of the University “La Sapienza” Hospital, Rome.Patients and participants13 critically ill patients were enrolled in this study. All were affected by disease involving both lungs and chest wall mechanics (ARDS in 4 patients, closed chest trauma without flail chest in 4 patients, cardiogenic pulmonary oedema with fluidic overload in 5 patients).Measurements and resultsRespiratory system and chest wall mechanics were evaluated during constant flow controlled mechanical ventilation in basal conditions (i. e. with the patients under apnoic sedation) and after paralysis with pancuronium bromide. In details, we simultaneously recorded airflow, tracheal pressure, esophageal pressure and tidal volume; with the end-inspiratory and end-expiratory airway occlusion technique we could evaluate respiratory system and chest wall elastance and resistances. Lung mechanics was evaluated by subtracting chest wall from respiratory system data. All data obtained in basal conditions (with the patients sedated with thiopental or propofol) and after muscle paralysis were compared using the Studentst test for paired data. The administration of pancuronium bromide to sedated patients induced a complete muscle paralysis without producing significant modification both to the viscoelastic and to the resistive parameters of chest wall and respiratory system.ConclusionsThis study demonstrates the lack of additive effects of muscle paralysis in mechanically ventilated, sedated patients. Also in view of the possible side effects of muscle paralysis, our results question the usefulness of generalyzed administration of neuromuscular blocking drugs in mechanically ventilated patients.

Exogenous reactive oxygen species deplete the isolated rat heart of antioxidants.

The effects of reactive oxygen species (ROS) on myocardial antioxidants and on the activity of oxidative mitochondrial enzymes were investigated in the following groups of isolated, perfused rat hearts. I: After stabilization the hearts freeze clamped in liquid nitrogen (n = 7). II: Hearts frozen after stabilization and perfusion for 10 min with xanthine oxidase (XO) (25 U/l) and hypoxanthine (HX) (1 mM) as a ROS-producing system (n = 7). III: Like group II, but recovered for 30 min after perfusion with XO + HX (n = 9). IV: The hearts were perfused and freeze-clamped as in group III, but without XO + HX (n = 7). XO + HX reduced left ventricular developed pressure and coronary flow to approximately 50% of the baseline value. Myocardial content of hydrogen peroxide (H2O2) and malondialdehyde (MDA) increased at the end of XO + HX perfusion, indicating that generation of ROS and lipid peroxidation occurred. Levels of H2O2 and MDA normalized during recovery. Superoxide dismutase, reduced glutathione and alpha-tocopherol were all reduced after ROS-induced injury. ROS did not significantly influence the tissue content of coenzyme Q10 (neither total, oxidized, nor reduced), cytochrome c oxidase, and succinate cytochrome c reductase. The present findings indicate that the reduced contractile function was not correlated to reduced activity of the mitochondrial electron transport chain. ROS depleted the myocardium of antioxidants, leaving the heart more sensitive to the action of oxidative injury.

Early and late onset bacteremia have different risk factors in trauma patients

ObjectiveThe aim of this study was to identify risk factors and to describe epidemiological patterns for early—(EOB) and late—onset bacteremias (LOB) after trauma.DesignA prospective study conducted on 141 consecutive trauma patients.SettingA general intensive care unit (ICU) of a university hospital.PatientsAll multiple trauma patients admitted to our general intensive care unit (ICU) from December 1990 to May 1992 were prospectively enrolled in the study. The following information was collected for each patient and recorded in a computer database: demography, severity of trauma according to the Abbreviated Injury Scale (AIS), severtity of trauma according to the Glasgow Coma Scale (GCS), presence of pneumothorax, pulmonary contusion, rib fractures, hemothorax, and abdominal trauma, use of mechanical ventilation, and placement of central venous catheters. Bacteremias were defined as EOB when onset occurred within 96 h after trauma, and as LOB when appearing after 96 h from trauma.ResultsThirty-seven patients developed bacteremia during their ICU stay (26%): 11 (29.7%) EOB and 26 (70.3%) LOB. Gram-positive cocci were isolated more frequently in EOB than in LOB (x2=4.1,P=0.04). The risk of EOB was significantly increased by the presence of pulmonary contusion [relative risk (RR) 15.0; confidence interval (CI) 1.99-113.25], pneumonia before the onset of bacteremia (RR 3.56; CI 1.17-10.69), AIS score greater than 32 and an abdominal injury score greater than 9 (RR 3.11; CI 1.02-9.49), while intravascular catheters and mechanical ventilation did not represent risk factors for EOB. LOB had a very different pattern and their risk was significantly increased by exposure to intravascular catheters (RR 4.96; CI 1.23-19.94) and to mechanical ventilation lasting more than 7 days (RR 3.6; CI 1.6-8.1).ConclusionsScoring with the AIS of the abdominal and thoracic trauma at admission to the ICU appears a useful tool for identifying trauma patients at increased risk of EOB. A rigorous policy of catheter placement and maintenance as a means of reducing late bacteremias in trauma patients is essential.

Quality of Life and Complications After Percutaneous Tracheostomy

Subjects with chronic respiratory failure who receive invasive mechanical ventilation trough a tracheostomy outside an acute care facility usually express a high level of satisfaction with their lives, despite severe physical limitations. A proper assessment of health-care quality of life may help in deciding whether to give or withhold therapeutic interventions in these subjects. Percutaneous tracheostomies may be accompanied by a number of complications, which may be associated with considerable morbidity and mortality. Health-care professionals of patients with tracheostomy should be aware of the risk factors for developing complications after tracheostomy and the impact of these complications on clinical outcomes. Multidisciplinary strategies are needed to optimize the clinical management of persons with a tracheostomy, preventing early or late complications.