Sten Walther

Increased mortality associated with meticillin-resistant Staphylococcus aureus (MRSA) infection in the Intensive Care Unit: Results from the EPIC II study

Controversy continues regarding whether the presence of meticillin resistance increases mortality risk in Staphylococcus aureus infections. In this study, we assessed the role of meticillin resistance in survival of patients with S. aureus infection included in the EPIC II point-prevalence study of infection in critically ill patients performed on 8 May 2007. Demographic, physiological, bacteriological and therapeutic data were collected for 13796 adult patients in 1265 participating Intensive Care Units (ICUs) from 75 countries on the study day. ICU and hospital outcomes were recorded. Characteristics of patients with meticillin-sensitive S. aureus (MSSA) and meticillin-resistant S. aureus (MRSA) infections were compared. Co-morbidities, age, Simplified Acute Physiology Score (SAPS) II, site of infection, geographical region and MRSA/MSSA were entered into a multivariate model, and adjusted odds ratios (ORs) [95% confidence interval (CI)] for ICU and hospital mortality rates were calculated. On the study day, 7087 (51%) of the 13796 patients were classified as infected. There were 494 patients with MRSA infections and 505 patients with MSSA infections. There were no significant differences between the two groups in use of mechanical ventilation or haemofiltration/haemodialysis. Cancer and chronic renal failure were more prevalent in MRSA than in MSSA patients. ICU mortality rates were 29.1% and 20.5%, respectively (P<0.01) and corresponding hospital mortality rates were 36.4% and 27.0% (P<0.01). Multivariate analysis of hospital mortality for MRSA infection showed an adjusted OR of 1.46 (95% CI 1.03-2.06) (P=0.03). In ICU patients, MRSA infection is therefore independently associated with an almost 50% higher likelihood of hospital death compared with MSSA infection.

Surveillance of microbial resistance in European Intensive Care Units: a first report from the Care-ICU programme for improved infection control

PurposeTo report initial results from a European ICU surveillance programme focussing on antibiotic consumption, microbial resistance and infection control.MethodsThirty-five ICUs participated during 2005. Microbial resistance, antibiotic consumption and infection control stewardship measures were entered locally into a web-application. Results were validated locally, aggregated by project leaders and fed back to support local audit and benchmarking.ResultsMedian (range) antibiotic consumption was 1,254 (range 348–4,992) DDD per 1,000 occupied bed days. The proportion of MRSA was median 11.6% (range 0–100), for ESBL phenotype of E. coli and K. pneumoniae 3.9% (0–80) and 14.3% (0–77.8) respectively, and for carbapenem-resistant P. aeruginosa 22.5% (0–100). Screening on admission for alert pathogens was commonly omitted, and there was a lack of single rooms for isolation.ConclusionsThe surveillance programme demonstrated wide variation in antibiotic consumption, microbial resistance and infection control measures. The programme may, by providing rapid access to aggregated results, promote local and regional audit and benchmarking of antibiotic use and infection control practices.

Pulmonary blood flow distribution in sheep: effects of anesthesia, mechanical ventilation, and change in posture

Background: Recent studies providing high‐resolution images of pulmonary perfusion have questioned the classical zone model of pulmonary perfusion. Hence the present work was undertaken to provide detailed maps of regional pulmonary perfusion to examine the influence of anesthesia, mechanical ventilation, and posture. Methods: Pulmonary perfusion was analyzed with intravenous fluorescent microspheres (15 micro meter) in six sheep studied in four conditions: prone and awake, prone with pentobarbital‐anesthesia and breathing spontaneously, prone with anesthesia and mechanical ventilation, and supine with anesthesia and mechanical ventilation. Lungs were air dried at total lung capacity and sectioned into approximately 1,100 pieces (about 2 cm3) per animal. The pieces were weighed and assigned spatial coordinates. Fluorescence was read on a spectrophotometer, and signals were corrected for piece weight and normalized to mean flow. Pulmonary blood flow heterogeneity was assessed using the coefficient of variation of flow data. Results: Pentobarbital anesthesia and mechanical ventilation did not influence perfusion heterogeneity, but heterogeneity increased when the animals were in the supine posture (P < 0.01). Gravitational flow gradients were absent in the prone position but present in the supine (P < 0.001 compared with zero). Pulmonary perfusion was distributed with a hilar‐to‐peripheral gradient in breathing spontaneously (P < 0.05). Conclusions: The influence of pentobarbital anesthesia and mechanical ventilation on pulmonary perfusion heterogeneity is small compared with the effect of changes in posture. Analysis of flow gradients indicate that gravity plays a small role in determining pulmonary blood flow distribution.

Long-term effect of the ICU-diary concept on quality of life after critical illness

Background: Critically ill patients often spend time in the intensive care unit (ICU) either unconscious or sedated. On recovery, they are often in a state of confusion with memory loss that may be associated with a longstanding reduction in health‐related quality of life (QoL). We hypothesised that the ICU‐diary concept could improve their QoL by filling in their memory gaps.

Administration of aerosolized terbutaline and budesonide reduces chlorine gas-induced acute lung injury.

BACKGROUND The pathophysiology and treatment of chlorine gas-induced acute lung injury is poorly characterized and based on anecdotal data. This study aimed to assess the effects of aerosolized beta-2 adrenergic agonist and corticosteroid therapy on chlorine gas-induced lung injury. METHODS Anesthetized, ventilated pigs were exposed to chlorine gas (400 parts per million for 20 minutes), then assigned randomly 30 minutes later to receive aerosolized terbutaline, budesonide, terbutaline followed by budesonide or placebo (6 pigs in each group). Hemodynamics, gas exchange, and lung mechanics were evaluated for another 5 hours. RESULTS All the animals demonstrated an immediate increase in airway and pulmonary artery pressure as well as sharp drops in arterial oxygen tension (PaO2) and lung compliance (CL). Recovery of PaO2 and CL was greatest in the terbutaline plus budesonide group, but therapy with terbutaline and budesonide alone also was associated with significant improvement in PaO2 and CL, as compared with placebo. CONCLUSIONS Treatment of acute chlorine gas lung injury with aerosolized terbutaline followed by aerosolized budesonide improved lung function. Combined treatment was more effective than treatment with either drug alone.

Positive end-expiratory pressure redistributes perfusion to dependent lung regions in supine but not in prone lambs.

OBJECTIVE To examine the influence of positive end-expiratory pressure (PEEP) and posture on the distribution of pulmonary blood flow. DESIGN Experimental study. SETTING University animal laboratory. SUBJECTS Seven anesthetized and mechanically-ventilated lambs. INTERVENTIONS Four conditions were studied in random order: prone or supine position, with or without 5 cm H2O PEEP. MEASUREMENTS AND MAIN RESULTS The distribution of pulmonary blood flow was assessed using fluorescent-labeled microspheres (15 microm) in small (approximately 1.7 cm3) lung regions. Pulmonary blood flow heterogeneity was evaluated using the coefficient of variation of blood flow of the lung regions. The number of regions analyzed were 1290+/-154 (SD) per animal. PEEP increased pulmonary blood flow heterogeneity in the supine position (47.0+/-7.7% to 54.1+/-7.3%, p < .01, paired Students t-test), but not in the prone position (40.4+/-8.1% to 39.6+/-11.5). Dorsal to ventral (gravitational) flow gradients were present only in the supine position, and increased with PEEP (-7.2%/cm vs. -10.4% cm, p< .001). CONCLUSIONS PEEP redistributes pulmonary perfusion to dependent lung regions in supine, but not in prone, anesthetized and mechanically-ventilated sheep.

Inhaled and intravenous corticosteroids both attenuate chlorine gas-induced lung injury in pigs

Background:  The accidental release of chlorine gas is a constant threat in urban areas. The purpose of this randomized, blinded, controlled experiment was to examine the effects of post‐injury administration of inhaled or intravenous corticosteroid in chlorine gas‐injured pigs followed for 23 h.

A porcine model of acute quadriplegic myopathy: a feasibility study.

Background:  The mechanisms underlying acute quadriplegic myopathy (AQM) are poorly understood, partly as a result of the fact that patients are generally diagnosed at a late stage of the disease. Accordingly, there is a need for relevant experimental animal models aimed at identifying underlying mechanisms.

Exposure to chlorine gas: effects on pulmonary function and morphology in anaesthetised and mechanically ventilated pigs

We have examined the effects of chlorine gas inhalation (110 and 140 ppm) on cardiovascular and pulmonary function in nine anaesthetised and mechanically ventilated pigs. Four additional pigs, which were similarly treated but not exposed to gas, served as controls. Severe pulmonary dysfunction developed when the animals were exposed to 100 l of 140 ppm chlorine gas for 10 min. Five of six animals died within 6 h of exposure. This dose induced a rapid drop in arterial oxygen tension (P < 0.001 compared with controls, ANOVA), a biphasic decline in lung compliance (P < 0.001) and a gradual increase in pulmonary vascular resistance (P < 0.001) that eventually caused a significant reduction in cardiac output ( P < 0.05). Microscopic examination showed sloughing of the bronchial epithelium and early infiltration with leukocytes, but largely intact alveoli. The sequence of events and the microscopic appearance suggested that the initial stage of pulmonary dysfunction (the first 1 or 2 h) was the result of mismatching of ventilation and perfusion. This was followed at a later stage by interstitial oedema and migration of immunocompetent cells into the tissue. We conclude that exposure to 100 l of 140 ppm chlorine gas induces a severe stereotypic lung injury with high mortality within 6 h in this anaesthetised animal model.

High antibiotic susceptibility among bacterial pathogens in Swedish ICUs Report from a nation-wide surveillance program using TA90 as a novel index of susceptibility

Local infection control measures, antibiotic consumption and patient demographics from 1999–2000 together with bacteriological analyses were investigated in 29 ICUs participating in the ICU-STRAMA programme. The median antibiotic consumption per ICU was 1147 (range 605–2143) daily doses per 1000 occupied bed d (DDD1000). Antibiotics to which >90% of isolates of an organism were susceptible were defined as treatment alternatives (TA90). The mean number of TA90 was low (1–2 per organism) for Enterococcus faecium (vancomycin:VAN), coagulase negative staphylococci (VAN), Pseudomonas aeruginosa (ceftazidime:CTZ, netilmicin: NET) and Stenotrophomonas maltophilia (CTZ, trimethoprim-sulfamethoxazole: TSU), but higher (3–7) for Acinetobacter spp. (imipenem:IMI, NET, TSU), Enterococcus faecalis (ampicillin:AMP, IMI, VAN), Serratia spp. (ciprofloxacin:CIP, IMI, NET), Enterobacter spp. (CIP, IMI, NET, TSU), E. coli (cefuroxime:CXM, cefotaxime/ceftazidime:CTX/CTZ, CIP, IMI, NET, piperacillin-tazobactam:PTZ, TSU), Klebsiella spp. (CTX/CTZ CIP, IMI, NET, PTZ, TSU) and Staphylococcus aureus (clindamycin, fusidic acid, NET, oxacillin, rifampicin, VAN). Of S. aureus isolates 2% were MRSA. Facilities for alcohol hand disinfection at each bed were available in 96% of the ICUs. The numbers of TA90 available were apparently higher than in ICUs in southern Europe and the US, despite a relatively high antibiotic consumption. This may be due to a moderate ecological impact of the used agents and the infection control routines in Swedish ICUs.