Showing papers in "Intensive Care Medicine in 2002"

Epidemiology of sepsis and infection in ICU patients from an international multicentre cohort study.

Abstract: Objectives: To examine the incidence of infections and to describe them and their outcome in intensive care unit (ICU) patients. Design and setting: International prospective cohort study in which all patients admitted to the 28 participating units in eight countries between May 1997 and May 1998 were followed until hospital discharge. Patients: A total of 14,364 patients were admitted to the ICUs, 6011 of whom stayed less than 24 h and 8353 more than 24 h. Results: Overall 3034 infectious episodes were recorded at ICU admission (crude incidence: 21.1%). In ICU patients hospitalised longer than 24 h there were 1581 infectious episodes (crude incidence: 18.9%) including 713 (45%) in patients already infected at ICU admission. These rates varied between ICUs. Respiratory, digestive, urinary tracts, and primary bloodstream infections represented about 80% of all sites. Hospital-acquired and ICU-acquired infections were documented more frequently microbiologically than community-acquired infections (71% and 86%, respectively vs. 55%). About 28% of infections were associated with sepsis, 24% with severe sepsis and 30% with septic shock, and 18% were not classified. Crude hospital mortality rates ranged from 16.9% in non-infected patients to 53.6% in patients with hospital-acquired infections at the time of ICU admission and acquiring infection during the ICU stay. Conclusions: The crude incidence of ICU infections remains high, although the rate varies between ICUs and patient subsets, illustrating the added burden of nosocomial infections in the use of ICU resources.

Specialist neurocritical care and outcome from head injury

Abstract: Objectives: To document the effect of neurocritical care, delivered by specialist staff and based on protocol-driven therapy aimed at intracranial pressure (ICP) and cerebral perfusion pressure (CPP) targets, on outcome in acute head injury. Design: Retrospective record review to compare presentation, therapy and outcome in patients with head injury referred to a regional neurosurgical centre, before and after establishment of protocol-driven therapy. Setting: Neurosciences Critical Care Unit (NCCU). Participants: Two hundred and eighty-five patients aged 18–65 years with at least one reactive pupil, referred with a diagnosis of head injury, requiring tracheal intubation and mechanical ventilation. Interventions: Measurement of Glasgow Outcome Scale 6 months after injury. Results: Patients from the two epochs were well matched for admission Glasgow Coma Scale and extracranial injuries. When all referred patients were considered, institution of protocol-driven therapy was not associated with a statistically significant increase in favourable outcomes (56.0% vs. 66.4%). However, we observed a significant increase in favourable outcomes in the severely head injured patients studied (40.4% vs. 59.6%). The proportion of favourable outcomes was also high (66.6%) in those presenting with evidence of raised ICP in the absence of a mass lesion and (60.0%) in those that required complex interventions to optimise ICP/CPP. Conclusions: Specialist neurocritical care with protocol-driven therapy is associated with a significant improvement in outcome for all patients with severe head injury. Such management may also benefit patients requiring no surgical therapy, some of whom may need complex therapeutic interventions. We found it impossible to predict need for such interventions from clinical features at presentation. These data suggest that specialist critical care with ICP/CPP guided therapy may benefit patients with severe head injury.

Continuous versus intermittent renal replacement therapy: a meta-analysis.

Abstract: Objective: Patients with critical illness commonly develop acute renal failure requiring mechanical support in the form of either continuous renal replacement therapy (CRRT) or intermittent hemodialysis (IRRT). As controversy exists regarding which modality should be used for most patients with critically illness, we sought to determine whether CRRT or IRRT is associated with better survival. Design: We performed a meta-analysis of all prior randomized and observational studies that compared CRRT with IRRT. Studies were identified through a MEDLINE search, the authors' files, bibliographies of review articles, abstracts and proceedings of scientific meetings. Studies were assessed for baseline characteristics, intervention, outcome and overall quality through blinded review. The primary end-point was hospital mortality, assessed by cumulative relative risk (RR). Measurements and results: We identified 13 studies (n=1400), only three of which were randomized. Overall there was no difference in mortality (RR 0.93 (0.79–1.09), p=0.29). However, study quality was poor and only six studies compared groups of equal severity of illness at baseline (time of enrolment). Adjusting for study quality and severity of illness, mortality was lower in patients treated with CRRT (RR 0.72 (0.60–0.87), p<0.01). In the six studies with similar baseline severity, unadjusted mortality was also lower with CRRT (RR 0.48 (0.34 –0.69), p<0.0005). Conclusions: Current evidence is insufficient to draw strong conclusions regarding the mode of replacement therapy for acute renal failure in the critically ill. However, the life-saving potential with CRRT suggested in our secondary analyses warrants further investigation by a large, randomized trial.

C-reactive protein: a valuable marker of sepsis.

Abstract: The word sepsis originated from the old Greek word meaning “putrefaction”. Nowadays, this term is used to describe the host systemic response to infectious stimuli that is characterised by clinical, haemodynamic, biochemical and inflammatory responses [1]. Sepsis is still one of the leading causes of death in the critically ill [2]. Despite all the research performed over the last two decades, few specific treatments have been shown to improve outcome. In daily practice, clinicians are often faced with two dilemmas: whether a patient is infected or not, and whether the antibiotic therapy being given is effective. The distinction between infection and sepsis is frequently difficult to make. Infection without sepsis can occur if the process remains localised. A sepsis-like syndrome without infection is also a frequent finding in conditions such as trauma and pancreatitis [3]. The attention of the clinician must be directed towards the early diagnosis of infection [4]. However, bacteriological confirmation may be difficult to obtain and negative cultures do not exclude the presence of infection. In addition, manifestations of sepsis such as fever, leukocytosis and tachycardia are neither specific nor sensitive for infection, nor for monitoring the response to therapy [5]. Increasing understanding of the various inflammatory cascade mechanisms has given new insights and provided several markers that, in conjunction with other manifestations of sepsis, can be useful as indicators of infection. C-reactive protein (CRP) is one such marker.

Stroke volume variations for assessment of cardiac responsiveness to volume loading in mechanically ventilated patients after cardiac surgery

Abstract: Objective: We hypothesized that measuring stroke volume variation (SVV) during mechanical ventilation by continuous arterial pulse contour analysis allows the accurate prediction and monitoring of changes in cardiac index (CI) in response to volume administration. Design and setting: Prospective study in an university hospital. Patients: Twenty mechanically ventilated patients following cardiac surgery. Interventions: Volume loading with oxypolygelatin (3.5%) 20 ml × body mass index over 10 min. Measurements and results: SVV, central venous pressure (CVP), pulmonary artery occlusion pressure (PAOP), left ventricular end-diastolic area index (LVEDAI) by transesophageal echocardiography, intrathoracic blood volume index (ITBVI) by transpulmonary thermodilution and CI were determined immediately before and after volume loading. SVV decreased, while CI, CVP, PAOP, ITBVI, and LVEDAI increased significantly. Percentage changes in CI were significantly correlated to percentage changes in SVV (r2=–0.59, p<0.001), ITBVI (r2=0.79, p<0.001), and PAOP (r2=0.33, p<0.05) and to baseline values of SVV (r2=0.55, p<0.05) and LVEDAI (r2=–0.68, p<0.001). Conclusions: SVV may help to determine the preload condition of ventilated patients following cardiac surgery and to predict and continuously monitor effects of volume administered as part of their hemodynamic management. An editorial regarding this article can be found in the same issue (http://dx.doi.org/10.1007/s00134-002-1229-2).

Central venous catheter use. Part 1: mechanical complications.

Abstract: Central venous catheters are being increasingly used in both intensive care units and general wards. Their use is associated with both mechanical and infectious complications. This review will focus on short- and medium-term mechanical complications of catheter placement; infectious complications will be discussed in a separate article. The most important risk factors are patient characteristics (morbidity, underlying disease and local anatomy), the expertise of the doctor performing the procedure, and nursing care. Placement aids, such as ultrasound-guided catheter insertion, are also discussed.

Noninvasive vs. conventional mechanical ventilation in patients with chronic obstructive pulmonary disease after failure of medical treatment in the ward: a randomized trial

Abstract: Objective. We conducted a randomized prospective study comparing noninvasive positive pressure ventilation (NPPV) with conventional mechanical ventilation via endotracheal intubation (ETI) in a group of patients with chronic obstructive pulmonary disease who failed standard medical treatment in the emergency ward after initial improvement and met predetermined criteria for ventilatory support. Design and setting. Prospective randomized study in a university hospital 13-bed general ICU. Patients. Forty-nine patients were randomly assigned to receive NPPV (n=23) or conventional ventilation (n=26). Results. both NPPV and conventional ventilation significantly improved gas exchanges. The two groups had similar length of ICU stay, number of days on mechanical ventilation, overall complications, ICU mortality, and hospital mortality. In the NPPV group 11 (48%) patients avoided intubation, survived, and had a shorter duration of ICU stay than intubated patients. One year following hospital discharge the NPPV group had fewer patients readmitted to the hospital (65% vs. 100%) or requiring de novo permanent oxygen supplementation (0% vs. 36%). Conclusions. The use of NPPV in patients with chronic obstructive pulmonary disease and acute respiratory failure requiring ventilatory support after failure of medical treatment avoided ETI in 48% of the patients, had the same ICU mortality as conventional treatment and, at 1-year follow-up was associated with fewer patients readmitted to the hospital or requiring for long-term oxygen supplementation. An editorial regarding this article can be found in the same issue (http://dx.doi.org/10.1007/s00134-002-1503-3).

Duration of life-threatening antecedents prior to intensive care admission

Abstract: Objective: To document the characteristics and incidence of serious abnormalities in patients pri- or to admission to intensive care units. Design and setting: Prospec- tive follow-up study of all patients admitted to intensive care in three acute-care hospitals. Patients: The study population totalled 551 pa- tients admitted to intensive care: 90 from the general ward, 239 from op- erating rooms (OR) and 222 from the Emergency Department (ED). Measurements and results: Patients from the general wards had greater severity of illness (APACHE II me- dian 21) than those from the OR (15) or ED (19). A greater percentage of patients from the general wards (47.6%) died than from OR (19.3%) and ED (31.5%). Patients from the general wards had a greater number of serious antecedents before admis- sion to intensive care 43 (72%) than those from OR 150 (64.4%) or ED 126 (61.8%). Of the 551 patients 62 had antecedents during the period 8-48 h before admission to intensive care, and 53 had antecedents both within 8 and 48 h before their admis- sion. The most common antecedents during the 8 h before admission were hypotension (n=199), tachycardia (n=73), tachypnoea (n=64), and sud- den change in level of consciousness (n=42). Concern was expressed in the clinical notes by attending staff in 70% of patients admitted from the general wards. Conclusions: In over 60% of patients admitted to intensive care potentially life-threatening ab- normalities were documented during the 8 h before their admission. This may represent a patient population who could benefit from improved re- suscitation and care at an earlier stage.

Pressure ulcers in intensive care patients: a review of risks and prevention.

Abstract: Objective. Review of the literature concerning pressure ulcers in the intensive care setting. Data source and study selections. Computerized databases (Medline from 1980 until 1999 and CINAHL from 1982 until 1999). The indexing terms for article retrieval were: "pressure ulcers", "pressure sores", "decubitus", and "intensive care". Nineteen articles met the selection criteria, and seven more were found from the references of these articles. One thesis was also analyzed. Results. Data on prevention, incidence, and costs of pressure ulcers in ICU patients are scarce. Overall there are no conclusive studies on the identification of pressure ulcer risk factors. None of the existing risk-assessment scales was developed especially for use in ICU patients. It is highly questionable to what extent these scales can be used in this setting as they are not even reliable in "standard care". The following risk factors might play a role in pressure ulcer development: duration of surgery and number of operations, fecal incontinence and/or diarrhea, low preoperative protein and albumin concentrations, disturbed sensory perception, moisture of the skin, impaired circulation, use of inotropic drugs, diabetes mellitus, too unstable to turn, decreased mobility, and high APACHE II score. The number of patients per study ranged from 5 from 638. The definition of "pressure ulcer" varied widely between authors or was not mentioned. Conclusions. Meaningful comparison cannot be made between the various studies because of the use of different grading systems for pressure ulcers, different methods of data collection, different (or lack of) population characteristics, unreported preventive measures, and the use of different inclusion and exclusion criteria. There is a need for well-conducted studies covering all these aspects.

Comparison of three different methods to confirm tracheal tube placement in emergency intubation

Abstract: Objectives Verification of endotracheal tube placement is of vital importance, since unrecognized esophageal intubation can be rapidly fatal (death, brain damage).The aim of our study was to compare three different methods for immediate confirmation of tube placement: auscultation, capnometry and capnography in emergency conditions in the prehospital setting. Design and setting. Prospective study in the prehospital setting. Patients and interventions. All adult patients (>18 years) were intubated by an emergency physician in the field. Tube position was initially evaluated by auscultation. Then, capnometry was performed with infrared capnometry and capnography with infrared capnography. The examiners looked for the characteristic CO2 waveform and value of end-tidal carbon dioxide (EtCO2) in millimeters of mercury. Determination of final tube placement was performed by a second direct visualization with laryngoscope. Data are mean ± SD and percentages. Measurements and results. Over a 4year period, 345 patients requiring emergency intubation were included. Indications for intubation included cardiac arrest (n=246; 71%) and non-arrest conditions (n=99; 29%). In nine (2.7%) patients, esophageal tube placement occurred. The esophageal intubations were followed by successful endotracheal intubations without complications. The capnometry (sensitivity and specificity 100%) and capnography (sensitivity and specificity 100%) were better than auscultation (sensitivity 94% and specificity 83%) in confirming endotracheal tube placement in non-arrest patients (p<0.05). Capnometry was highly specific (100%) but not sensitive (88%) for correct endotracheal intubation in patients with cardiopulmonary arrest (capnometry versus auscultation and capnometry versus capnography, p<0.05). Conclusion. Capnography is the most reliable method to confirm endotracheal tube placement in emergency conditions in the prehospital setting.

Decision to extubate.

Abstract: The need for reintubation within 24-72 h of planned extubation is a common event, occurring in 2-25% of extubated patients. Risk factors for extubation failure include being a medical, multidisciplinary or paediatric patient; age >70 years; a longer duration of mechanical ventilation; use of continuous intravenous sedation; and anaemia (haemoglobin <10 g/dl or haematocrit <30%) at the time of extubation. The pathophysiology of extubation failure can be distinct from that seen with weaning failure and includes upper airway obstruction, inadequate cough, excess respiratory secretions, encephalopathy, and cardiac dysfunction. Extubation failure prolongs the duration of mechanical ventilation, increases the length of ICU and hospital stay, increases the need for tracheostomy, and is associated with a higher hospital mortality. Great emphasis has been placed on accurately predicting extubation outcome because extubation delay is also associated with increased length of stay and mortality. Tests designed to assess for upper airway obstruction, secretion volume, and the effectiveness of cough seem most promising for improving the decision to extubate. Mortality increases with delays in reintubation for patients failing extubation. Timely identification of patients at elevated risk of extubation failure followed by rapid re-establishment of ventilatory support can improve outcome.

Plasmapheresis in severe sepsis and septic shock: a prospective, randomised, controlled trial.

Abstract: Objective. To determine the therapeutic efficacy and safety of plasmapheresis in the treatment of patients with severe sepsis and septic shock. Design. Prospective, randomised, clinical trial with a planned, midstudy, interim analysis. Setting. Intensive care unit in a university hospital in Archangels, Russia. Patients. Consecutive patients with severe sepsis or septic shock. Interventions. One hundred and six patients were randomised to receive either standard therapy or an add-on treatment with plasmapheresis. Measurements and results. The primary endpoint was 28-day survival. Septic shock was diagnosed in 57% of the plasmapheresis-treated patients and 54% of the control patients. Mean APACHE III score at entry was 56.4 in the plasmapheresis group and 53.5 in the control group. The 28-day, all-cause mortality rate was 33.3% (18/54) in the plasmapheresis group and 53.8% (28/52) in the control group. This represents a relative risk for fatal outcome in the plasmapheresis group of 0.61, an absolute risk reduction of 20.5% and a number of patients needed to treat of 4.9. Apart from six transient episodes of hypotension and one allergic reaction to fresh frozen plasma, no adverse reactions were attributable to the plasmapheresis treatment in this study. Conclusions. Plasmapheresis may be an important adjuvant to conventional treatment to reduce mortality in patients with severe sepsis or septic shock. Plasmapheresis is a safe procedure in the treatment of septic patients. A prospective randomised multicentre trial is warranted to confirm our results and to determine which subgroups of septic patients will benefit most from this treatment modality.

Effects of therapeutic hypothermia on intracranial pressure and outcome in patients with severe head injury

Abstract: Objective. Therapeutic hypothermia may improve outcome in patients with severe head injury, but clinical studies have produced conflicting results. We hypothesised that the severe side effects of artificial cooling might have masked the positive effects in earlier studies, and we treated a large group of patients with severe head injury with hypothermia using a strict protocol to prevent the occurrence of cooling-induced side effects. Design. Prospective clinical trial. Setting. University teaching hospital. Patients. Hundred thirty-six consecutive patients admitted to our hospital with severe head injury (Glasgow Coma Scale (GCS) ≤8). Measurements and results. Patients included are the 136 patients with a GCS of 8 or less on admission in whom intracranial pressure (ICP) remained above 20 mmHg in spite of therapy according to a step-up protocol. Those who responded to the last step of our protocol (barbiturate coma) constituted the control group (n=72). Those who did not respond to barbiturate coma (n=64) were treated with moderate hypothermia (32–34°C). Average APACHE II scores were higher (28.9±14.4 vs 25.2±12.1, p<0.01) and average GCS at admission slightly lower (5.37±1.8 vs 5.9±2.1, p<0.05) in the hypothermia group, indicating greater severity of illness and more severe neurological injury. Predicted mortality was 86% for the hypothermia group versus 80% in controls (p<0.01). Actual mortality rates were significantly lower: 62% versus 72%; the difference in mortality between hypothermic patients and controls was significant (p<0.05). The number of patients with good neurological outcome was also higher in the hypothermia group: 15.7% versus 9.7% for hypothermic patients versus controls, respectively (p<0.02). These differences were explained almost entirely by the subgroup of patients with GCS of 5 or 6 at admission (mortality 52% vs 76%, p<0.01; good neurological outcome 29% vs 8%, p<0.01). Conclusions. Artificial cooling can significantly improve survival and neurological outcome in patients with severe head injury when used in a protocol with great attention to the prevention of side effects. Because there is likely to have been bias against the hypothermia group in this study, the positive effects of hypothermia might even have been underestimated. In addition, our results confirm the value of therapeutic hypothermia in treating refractory intracranial hypertension.

A randomised, controlled trial of the pulmonary artery catheter in critically ill patients.

Abstract: Objective: To compare the survival and clinical outcomes of critically ill patients treated with the use of a pulmonary artery catheter (PAC) to those treated without the use of a PAC. Design: Prospective, randomised, controlled, clinical trial from October 1997 to February 1999. Setting: Adult intensive care unit at a large teaching hospital. Patients: Two hundred one critically ill patients were randomised either to a PAC group (n=95) or the control group (n=106). One patient in the control group was withdrawn from the study and five patients in the PAC group did not receive a PAC. All participants were available for follow-up. Interventions: Participants were assigned to be managed either with the use of a PAC (PAC group) or without the use of a PAC (control group). Main outcome measures: Survival to 28 days, intensive care and hospital length of stay and organ dysfunction were compared on an intention-to-treat basis and also on a subgroup basis for those participants who successfully received a PAC. Results: There was no significant difference in mortality between the PAC group [46/95 (47.9%)] and the control group [50/106 (47.6)] (95% confidence intervals for the difference –13 to 14%, p>0.99). The mortality for participants who had management decisions based on information derived from a PAC was 41/91 (45%, 95% confidence intervals –11 to 16%, p=0.77). The PAC group had significantly more fluids in the first 24 h (4953 (3140, 7000) versus 4292 (2535, 6049) ml) and an increased incidence of renal failure (35 versus 20% of patients at day 3 post randomisation p<0.05) and thrombocytopenia (p<0.03). Conclusions: These results suggest that the PAC is not associated with an increased mortality.

The Multiple Organ Dysfunction Score (MODS) versus the Sequential Organ Failure Assessment (SOFA) score in outcome prediction.

Abstract: Objective. To compare outcome prediction using the Multiple Organ Dysfunction Score (MODS) and the Sequential Organ Failure Assessment (SOFA), two of the systems most commonly used to evaluate organ dysfunction in the intensive care unit (ICU). Design. Prospective, observational study. Setting. Thirty-one-bed, university hospital ICU. Patients and participants. Nine hundred forty-nine ICU patients. Measurements and results. The MODS and the SOFA score were calculated on admission and every 48 h until ICU discharge. The Acute Physiology and Chronic Health Evaluation (APACHE) II score was calculated on admission. Areas under receiver operating characteristic (AUROC) curves were used to compare initial, 48 h, 96 h, maximum and final scores. Of the 949 patients, 277 died (mortality rate 29.1%). Shock was observed in 329 patients (mortality rate 55.3%). There were no significant differences between the two scores in terms of mortality prediction. Outcome prediction of the APACHE II score was similar to the initial MODS and SOFA score in all patients, and slightly worse in patients with shock. Using the scores' cardiovascular components (CV), outcome prediction was better for the SOFA score at all time intervals (initial AUROC SOFA CV 0.750 vs MODS CV 0.694, p<0.01; 48 h AUROC SOFA CV 0.732 vs MODS CV 0.675, p<0.01; and final AUROC SOFA CV 0.781 vs MODS CV 0.674, p<0.01). The same tendency was observed in patients with shock. There were no significant differences in outcome prediction for the other five organ systems. Conclusions. MODS and SOFA are reliable outcome predictors. Cardiovascular dysfunction is better related to outcome with the SOFA score than with the MODS.

Prevention of severe Candida infections in nonneutropenic, high-risk, critically ill patients: a randomized, double-blind, placebo-controlled trial in patients treated by selective digestive decontamination.

Abstract: Objective. Infections caused by Candida spp. are a major cause of morbidity and mortality in critically ill patients and usually develop from endogenous colonization. We assessed the effectiveness of adding fluconazole to a selective digestive decontamination regimen to prevent candidal infections. Design and setting. We performed a prospective, randomized, double-blind, placebo-controlled trial among medical and surgical intensive care unit patients at a large university hospital. Patients. All adult patients mechanically ventilated for at least 48 h with an expectation to remain so for at least an additional 72 h, and receiving selective decontamination of the digestive tract. Interventions. Patients were randomly assigned fluconazole 100 mg daily (n=103) or placebo (n=101). Measurements and results. Candida infections occurred less frequently in the fluconazole group (5.8%) than in the placebo group (16%; rate ratio 0.35; Cl95 0.11–0.94). Some 90% of candidemia episodes occurred in the placebo group (rate ratio for fluconazole use 0.10; Cl95 0.02–0.74). The rate of treatment failure, development of candidal infection, or increased colonization, was 32% in the fluconazole group and 67% in the placebo group (P<0.001). Crude in-hospital mortality was similar in the two groups (39% fluconazole vs. 41% placebo). Conclusions. Prophylactic use of fluconazole in a selected group of mechanically ventilated patients at high risk for infection reduces the incidence of Candida infections, in particular candidemia.

Chest physiotherapy for the prevention of ventilator-associated pneumonia

Abstract: Objective. Pneumonia is an important complication in patients who are intubated and mechanically ventilated, when it is commonly referred to as ventilator-associated pneumonia (VAP). Since VAP may be contributed to by impaired sputum clearance, we studied whether chest physiotherapy designed to enhance sputum clearance decreases the occurrence of VAP.

Seven cases of fungemia with Saccharomyces boulardii in critically ill patients.

Abstract: Saccharomyces boulardii (Sb) is a particular strain of Saccharomyces cerevisiae (Sc). This viable yeast is used in intensive care adult patients, delivered in packets of 500 mg, for preventing diarrhea associated with antibiotics or enteral feeding at a regimen of 1-2 g/day. Between June 1996 and October 1998, seven cases of fungemia with Sb occurred in a 12-bed intensive care unit (ICU). All the patients concerned were severely ill patients, mechanically ventilated, treated by broad spectrum antibiotics with central venous catheter and were pretreated with Sb, except for one patient. In this study, Sb was identified by specific mycologic methods and confirmed the genomic identity between isolates of blood culture and yeasts from the treatment packets, contrary to a few other reports concerning Saccharomyces species published in international literature. The hypothesis discussed for explaining these cases of Sb fungemia are: (1) an intestinal translocation of Sb administered at a high dosage in severely ill patients, (2) a contamination of the central venous catheter, especially in the patient not pretreated with Sb and (3) a massive colonization of critically ill patients by the yeast as has been reported for Candida species. We note that cases of fungemia with Sc and Sb have become more and more frequent in the international literature during the last 10 years and we do not recommend administering Sb treatment in critically ill patients.

Relationship between ventilatory settings and barotrauma in the acute respiratory distress syndrome.

Abstract: Objective: High pressures or volumes may increase the risk of barotrauma in the acute respiratory distress syndrome (ARDS). Methods: The first part of the study analyzed data from a prospective trial of two ventilation strategies in 116 patients with ARDS retrospectively, and ventilatory pressures and volumes were compared in patients with or without pneumothorax. The second part consisted of a literature analysis of prospective trials (14 clinical studies, 2270 patients) describing incidence and risk factors for barotrauma in ARDS patients, and mean values of ventilatory parameters were plotted against incidence of barotrauma. Results: In our clinical trial comparing two tidal volumes, 15 patients (12.3%) developed pneumothorax. There was no significant difference in any pressure or volume between these patients and the rest of the population, including end-inspiratory plateau pressure (Pplat), driving pressure (Pplat-PEEP), respiratory rate and compliance. Multiple trauma was more frequent among patients with pneumothorax (27%) than in those without (7%). Duration of mechanical ventilation tended to be longer with pneumothorax. In the literature review, the incidence of barotrauma varied between 0% and 49%, and correlated strongly with Pplat, with a high incidence above 35 cmH2O, and with compliance, with a high incidence below 30 ml/cmH2O. Conclusion: Clinical studies maintaining Pplat lower than 35 cmH2O found no apparent relationship between ventilatory parameters and pneumothorax. Analysis of the literature suggests a correlation when patients receive mechanical ventilation with Pplat levels exceeding 35 cmH2O.

Central venous catheter use. Part 2: infectious complications.

Abstract: Central venous catheters (CVCs) are used with increasing frequency in the intensive care unit and in general medical wards. Catheter infection, the most frequent complication of CVC use, is associated with increased morbidity, mortality, and duration of hospital stay. Risk factors in the development of catheter colonisation and bloodstream infection include patient factors (increased risk associated with malignancy, neutropenia, and shock) and treatment-related factors (increased risk associated with total parenteral nutrition, ICU admission for any reason, and endotracheal intubation). Other risk factors are prolonged catheter indwelling time, lack of asepsis during CVC insertion, and frequent manipulation of the catheter. The most important factor is catheter care after placement. Effects of CVC tunnelling on infection rates depend to a large extent on indwelling time and the quality of catheter care. Use of polyurethane dressings can increase the risk of colonisation compared to regular gauze dressing. Thrombus formation around the CVC tip increases the risk of infection; low-dose anticoagulants may decrease this risk. New developments such as CVC impregnation with antibiotics may reduce the risk of infection. Reducing catheter infection rates requires a multiple-strategy approach. Therefore, ICUs and other locations where CVCs are used should implement strict guidelines and protocols for catheter insertion, care, and maintenance.

Predictive value of procalcitonin and interleukin 6 in critically ill patients with suspected sepsis

Abstract: Objective. To evaluate the performance of procalcitonin (PCT), interleukin-6 (IL-6), C-reactive protein, leukocyte count, D-dimer, and antithrombin III at onset of septic episode and 24 h later in prediction of hospital mortality in critically ill patients with suspected sepsis.

Extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae bloodstream infection: risk factors and clinical outcome.

Abstract: Objectives. To study the risk factor for nosocomial bacteremia caused by Escherichia coli or Klebsiella pneumoniae producing extended-spectrum beta-lactamase (ESBL) and the influence on patient outcome. Design. Retrospective, single-center study of consecutive bacteremic patients. Settings. A university-affiliated teaching hospital. Patients. A total of 85 patients with nosocomial bacteremia due to E. coli or K. pneumoniae were enrolled. Intervention. None. Measurements and main results. The demographic characteristics and clinical information including treatment were recorded upon review of patients' records. The primary end point was hospital mortality. Twenty-seven percent of isolates produced ESBLs. Previous treatment with 3rd-generation cephalosporins was the only independent risk factor for bacteremia due to ESBL-producing pathogens [odds ratio (OR) 4.146, P=0.008]. Antibiotic treatment was considered appropriate in 71 cases (83%), and failed in 23 patients (27%). Twenty-one patients (25%) died in the hospital. Antibiotic treatment failure was the only independent risk factor for hospital mortality (OR 15.376, P=0.001). Inappropriate antibiotic treatment might lead to significantly higher mortality rate (7/14 vs 14/71, P=0.016). Patients treated with imipenem were more likely to survive while those receiving cephalosporin treatment tended to have a poorer outcome (1/19 vs 14/40, P=0.023). Conclusions. More judicious use of cephalosporins, especially 3rd-generation cephalosporins, may decrease ESBL-producing E. coli or K. pneumoniae bacteremia, and also improve patient outcome.

Combination of venoarterial PCO2 difference with arteriovenous O2 content difference to detect anaerobic metabolism in patients.

Abstract: Objective: Under conditions of tissue hypoxia total CO2 production (VCO2) should be less reduced than O2 consumption (VO2) since an anaerobic CO2 production should occur. Thus the VCO2/VO2 ratio, and hence the venoarterial CO2 tension difference/arteriovenous O2 content difference ratio (ΔPCO2/C(a-v)O2), should increase. We tested the value of the ΔPCO2/C(a-v)O2 ratio in detecting the presence of global anaerobic metabolism as defined by an increase in arterial lactate level above 2 mmol/l (Lac+). Design and setting: Retrospective study over a 17-month period in medical intensive care unit of a university hospital. Patients: We obtained 148 sets of measurements in 89 critically ill patients monitored by a pulmonary artery catheter. Results: The ΔPCO2/C(a-v)O2 ratio was higher in those with increased (n=73) than in the normolactatemic group (2.0±0.9 vs. 1.1±0.6, p<0.0001). Among all the O2- and CO2-derived parameters the ΔPCO2/C(a-v)O2 ratio had the highest correlation with the arterial lactate level (r=0.57). Moreover, for a threshold value of 1.4 the ΔPCO2/C(a-v)O2 ratio predicted significantly better than the other parameters (receiver operating characteristic curves) the presence of hyperlactatemia (positive and negative predictive values of 86% and 80%, respectively). The overall survival estimate at 1 month was greater when the ΔPCO2/C(a-v)O2 ratio was less than 1.4 on the first set of measurements (38±10% vs. 20±8%, p<0.01). Conclusion: The ΔPCO2/C(a-v)O2 ratio seems a reliable marker of global anaerobic metabolism. Its calculation would be helpful for a better interpretation of pulmonary artery catheter data.

Kinetic and reversibility of mechanical ventilation-associated pulmonary and systemic inflammatory response in patients with acute lung injury

Abstract: Objective. To investigate the kinetic and reversibility of mechanical ventilation-associated pulmonary and systemic inflammatory response in patients with acute lung injury (ALI).

Survival of mechanically ventilated patients admitted to a specialised weaning centre

Abstract: Objective. Hospital mortality and survival rates of long-term ventilated patients. Design. Retrospective cohort study. Setting. Specialised national weaning centre. Intervention. Protocol-directed liberation from ventilator. Patients. Four hundred three of 640 patients with prolonged mechanical ventilation (MV) who were admitted to our respiratory intensive care unit (RICU) were studied. MV lasted longer than 2 weeks and patients had failed more than two weaning trials in the referring ICUs. The majority of patients (59.3%) had chronic obstructive pulmonary disease (COPD). Results. After a mean duration of 41 days of MV prior to transfer, 68% of patients were liberated from the ventilator. In total, 98 of 403 patients (24.3%) died during the stay in our hospital, 305 patients (75.7%) were discharged. Compared to the non-survivors, the survivors were characterised by younger age, longer length of stay in our RICU, lower severity of illness scores at admission, fewer cardiac illnesses and a higher rate of weaning success. In 31.5% of the discharged patients non-invasive MV (NIV) was initiated during the stay at our unit. We gathered follow-up data on 293 patients (96.1%). Post-discharge survival rates were 67.6% at 3 months, 49.4% at 1 year and 38.1% at 3 years. Length of survival was significantly dependent on age, weaning success and main diagnosis (i.e., prognosis in COPD is worse compared to thoracic restriction, neuromuscular disease and others) in the multivariate analysis. Conclusions. Difficult-to-wean patients have a high hospital mortality rate and poor long-term prognosis. Age, main diagnosis, severity of illness, weaning success and institution of NIV predict survival.

Pulmonary and cardiac sequelae of subarachnoid haemorrhage: time for active management?

Abstract: Cardiac injury and pulmonary oedema occurring after acute neurological injury have been recognised for more than a century. Catecholamines, released in massive quantities due to hypothalamic stress from subarachnoid haemorrhage (SAH), result in specific myocardial lesions and hydrostatic pressure injury to the pulmonary capillaries causing neurogenic pulmonary oedema (NPO). The acute, reversible cardiac injury ranges from hypokinesis with a normal cardiac index, to low output cardiac failure. Some patients exhibit both catastrophic cardiac failure and NPO, while others exhibit signs of either one or other, or have subclinical evidence of the same. Hypoxia and hypotension are two of the most important insults which influence outcome after acute brain injury. However, despite this, little attention has hitherto been devoted to prevention and reversal of these potentially catastrophic medical complications which occur in patients with SAH. It is not clear which patients with SAH will develop important cardiac and respiratory complications. An active approach to investigation and organ support could provide a window of opportunity to intervene before significant hypoxia and hypotension develop, potentially reducing adverse consequences for the long-term neurological status of the patient. Indeed, there is an argument for all SAH patients to have echocardiography and continuous monitoring of respiratory rate, pulse oximetry, blood pressure and electrocardiogram. In the event of cardio-respiratory compromise developing i.e. cardiogenic shock and/or NPO, full investigation, attentive monitoring and appropriate intervention are required immediately to optimise cardiorespiratory function and allow subsequent definitive management of the SAH.

Low-dose dopamine: a systematic review.

Abstract: To determine the magnitude of the treatment effect of low-dose dopamine on renal function in patients at risk of and in patients with early renal injury. Data sources. MEDLINE, citation review of relevant primary and review articles, personal files, and contact with expert informants. Study selection. Randomized controlled studies that compared low-dose dopamine with placebo for the prevention or treatment of acute renal dysfunction. From 122 articles screened, 21 met the inclusion criteria for this meta-analysis. Of these six, were excluded. Data extraction. Fifteen studies containing 970 subjects were analyzed. Descriptive and outcome data were extracted. The main outcome measure was the absolute change in serum creatinine. In addition the number of patients who developed an acute decline in renal function was recorded. The meta-analysis was performed using the random effects model. Data synthesis. The meta-analysis demonstrated no significant difference between the absolute change in serum creatinine (5.1 μmol/l, 95% CI of –6.5 to +16.7) and the incidence of acute renal dysfunction (31% vs 33%, relative risk 1.01, 95% CI of 0.79–1.28) between those patients receiving low-dose dopamine and the control group. In addition, no sub-group of patients showed improved renal function with low-dose dopamine. Conclusions. The results of this meta-analysis confirms that low-dose dopamine has no reno-protective effect. Considering the potential side-effects of dopamine this agent should not be used for this indication.

Iatrogenic cerebral air embolism: importance of an early hyperbaric oxygenation.

Abstract: Objectives: To assess the relationship between the time period before hyperbaric oxygenation therapy (HBO) and clinical outcome in patients with iatrogenic cerebral air embolism. Design and setting: Retrospective study in a hyperbaric chamber and medical intensive care unit of a university hospital. Patients: All patients with air embolism from 1980 to 1999. Interventions: We retrieved the cases of 86 patients who benefited from an identical HBO and analyzed the relationship between the time period before HBO and clinical outcome. Results: Patients treated with HBO less than 6 h had a better outcome than those treated later. In patients treated within this delay the cause was venous air embolism in 84% and arterial air embolism in only 16% of cases. After this delay the cause was venous air embolism (53%) and arterial air embolism (47%). Patients with venous air embolism and recovery had a shorter delay than patients with sequelae or death (2 h 15 min vs. 4 h). Patients with venous air embolism treated less than 6 h had a better outcome than those treated later. In patients with arterial air embolism the time period before HBO was longer than in venous air embolism (8 h vs. 3 h) and the outcome worse (recovery in 35% vs. 67%). In patients with arterial air embolism no difference in the time period was found between patients with recovery and sequelae or death. Conclusions: We stress the beneficial effect of an early HBO in air embolism, the importance of an increased awareness of physicians concerned with this severe complication, and the need to develop techniques to detect air emboli in the cerebral circulation.

Is the bispectral index appropriate for monitoring the sedation level of mechanically ventilated surgical ICU patients

Abstract: Objective: To determine the value of the bispectral index (BIS) in assessing the depth of sedation in sedated and mechanically ventilated ICU patients, compared with clinical sedation scores. Design and setting: Prospective convenience sample in a 12-bed anesthesiological-surgical ICU of a university hospital. Patients: 19 consecutive patients without any central neurological diseases requiring mechanical ventilation for more than 24 h. Measurements: BIS version 3.12 and clinical depth of sedation assessed by the modified Observers's Assessment of Alertness/Sedation Scale, modified Glasgow Coma Scale, modified Ramsay Scale, Cook Scale, and Sedation-Agitation Scale were measured twice daily while patients were intubated and once daily after extubation until discharged from ICU. Results: there was a moderate correlation between BIS and each sedation score in 11 patients (58%, "BIS patients") and no correlation in 8 patients (42%, "non-BIS patients"). We found no parameters distinguishing between these two groups. On average eight measurements were necessary to establish a statistical correlation. In the BIS patients the slopes of the linear regression curves showed significant differences for all BIS score combinations with increasing scattering at deeper sedation levels. Conclusions: BIS is correlated only in some ICU patients with the clinical assessment of their sedation level as based on various scores. At deeper sedation levels the interindividual differences increase. There were no criteria found to distinguish patients with and without correlation. This suggests that the BIS is not suitable for monitoring the sedation in a heterogeneous group of surgical ICU patients.

Clinical implications of antibiotic-induced endotoxin release in septic shock

Abstract: Antibiotic-induced release of bacterial cell wall components can have immediate adverse effects for the patient. This article reviews the data on endotoxin release after initiation of antibiotic therapy and its role in the pathogenesis of sepsis and septic shock. Antibiotics differ in their potential to liberate endotoxins from bacterial cell walls. When used for treatment of systemic Gram-negative infection, some classes of β-lactam antibiotics lead to markedly increased levels of free endotoxins while treatment with carbapenems and aminoglycosides produces relatively low amounts of endotoxins. Antibiotics that induce the formation of long, aberrant bacterial cells before effectively killing the microorganisms show the highest degree of endotoxin liberation. There is increasing evidence from animal models and clinical studies of sepsis that the antibiotic-mediated release of biologically active cell wall components derived from Gram-positive, Gram-negative or fungal organisms is associated with a rapid clinical deterioration.