J. Matthias Walz

Perioperative pulmonary outcomes in patients with sleep apnea after noncardiac surgery.

BACKGROUND:Although patients with sleep apnea (SA) are considered to be at increased risk for postoperative complications, evidence supporting increased risk of perioperative pulmonary morbidity is limited. The objective of this study, therefore, was to analyze perioperative demographics and pulmonary outcomes of patients with SA after orthopedic and general surgical procedures using a population-based sample. We hypothesized that SA is an independent risk factor for perioperative pulmonary complications, thus providing a basis for an increase in the utilization of resources, including intensive monitoring and development of strategies to prevent and treat these events. METHODS:National Inpatient Sample data for each year between 1998 and 2007 were accessed. Orthopedic and general surgical procedures were included and discharges with a diagnosis code for SA were identified. Patients with the diagnosis of SA were matched to those without the disease based on demographic variables using the propensity scoring method. Aspiration pneumonia, adult respiratory distress syndrome (ARDS), pulmonary embolism (PE), and the need for intubation and mechanical ventilation were the primary outcomes. Odds ratio (OR) and absolute risk reduction along with 95% confidence interval were reported. RESULTS:We identified 2,610,441 entries for orthopedic and 3,441,262 for general surgical procedures performed between 1998 and 2007. Of those, 2.52% and 1.40%, respectively, carried a diagnosis of SA. Patients with SA developed pulmonary complications more frequently than their matched controls after both orthopedic and general surgical procedures, respectively (i.e., aspiration pneumonia: 1.18% vs 0.84% and 2.79% vs 2.05%; ARDS: 1.06% vs 0.45% and 3.79% vs 2.44%; intubation/mechanical ventilation: 3.99% vs 0.79% and 10.8% vs 5.94%, all P values <0.0001). Comparatively, PE was more frequent in SA patients after orthopedic procedures (0.51% vs 0.42%, P = 0.0038) but not after general surgical procedures (0.45% vs 0.49%, P = 0.22). SA was associated with a significantly higher adjusted OR of developing pulmonary complications after both orthopedic and general surgical procedures, respectively, with the exception of PE (OR for aspiration pneumonia: 1.41 [1.35, 1.47] and 1.37 [1.33, 1.41]; for ARDS: 2.39 [2.28, 2.51] and 1.58 [1.54, 1.62]; for PE: OR 1.22 [1.15, 1.29] and 0.90 [0.84, 0.97]; for intubation/mechanical ventilation: 5.20 [5.05, 5.37] and 1.95 [1.91, 1.98]). CONCLUSION:SA is an independent risk factor for perioperative pulmonary complications. Our results may be used for hypothesis generation for clinical studies targeted to improve perioperative outcomes in this patient population.

Prevention of Central Venous Catheter Bloodstream Infections

The majority of nosocomial bloodstream infections in critically ill patients originate from an infected central venous catheter (CVC). Catheter-related bloodstream infections (CRBSIs) cause significant morbidity and mortality and increase the cost of care. The most frequent causative organisms for CRBSI are coagulase-negative staphylococci (CoNSs), Staphylococcus aureus, enterococci, and Candida species. The path to infection frequently includes migration of skin organisms at the insertion site into the cutaneous catheter tract, resulting in microbial colonization of the catheter tip and formation of biofilm. Evidence-based strategies for the prevention of CRBSI include behavioral and educational interventions, effective skin antisepsis coupled with maximum barrier precautions, the use of antiseptic dressings, and the use of antiseptic or antibiotic impregnated catheters. Achieving and maintaining very low rates of CRBSI requires a multidisciplinary approach involving the entire health care team, the use of novel technologies in patients with the highest risk of CRBSI, and frequent reeducation of staff.

Anti-infective external coating of central venous catheters: A randomized, noninferiority trial comparing 5-fluorouracil with chlorhexidine/silver sulfadiazine in preventing catheter colonization*

Objective:The antimetabolite drug, 5-fluorouracil, inhibits microbial growth. Coating of central venous catheters with 5-fluorouracil may reduce the risk of catheter infection. Our objective was to compare the safety and efficacy of central venous catheters externally coated with 5-fluorouracil with those coated with chlorhexidine and silver sulfadiazine. Design:Prospective, single-blind, randomized, active-controlled, multicentered, noninferiority trial. Setting:Twenty-five US medical center intensive care units. Patients:A total of 960 adult patients requiring central venous catheterization for up to 28 days. Interventions:Patients were randomized to receive a central venous catheter externally coated with either 5-fluorouracil (n = 480) or chlorhexidine and silver sulfadiazine (n = 480). Measurements and Main Results:The primary antimicrobial outcome was a dichotomous measure (<15 colony-forming units or ≥15 colony-forming units) for catheter colonization determined by the roll plate method. Secondary antimicrobial outcomes included local site infection and catheter-related bloodstream infection. Central venous catheters coated with 5-fluorouracil were noninferior to chlorhexidine and silver sulfadiazine coated central venous catheters with respect to the incidence of catheter colonization (2.9% vs. 5.3%, respectively). Local site infection occurred in 1.4% of the 5-fluorouracil group and 0.9% of the chlorhexidine and silver sulfadiazine group. No episode of catheter-related bloodstream infection occurred in the 5-fluorouracil group, whereas two episodes were noted in the chlorhexidine and silver sulfadiazine group. Only Gram-positive organisms were cultured from 5-fluorouracil catheters, whereas Gram-positive bacteria, Gram-negative bacteria, and Candida were cultured from the chlorhexidine and silver sulfadiazine central venous catheters. Adverse events were comparable between the two central venous catheter coatings. Conclusions:Our results suggest that central venous catheters externally coated with 5-fluorouracil are a safe and effective alternative to catheters externally coated with chlorhexidine and silver sulfadiazine when used in critically ill patients.

Perioperative mortality in patients with pulmonary hypertension undergoing major joint replacement.

BACKGROUND: There is a paucity of perioperative outcomes data for patients with chronic pulmonary hypertension (PHTN) undergoing noncardiac surgery. Clinicians, therefore, have little information on which to evaluate the risk for morbidity and mortality in this patient population. In this study, we evaluated the incidence and risks of perioperative morbidity and mortality in patients with PHTN undergoing primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). METHODS: Using the largest inpatient database in the United States (National Inpatient Sample), we identified entries for THA and TKA between the years of 1998 and 2006. Patients with the diagnosis of PHTN were identified and matched to those without the disease based on health-related demographic variables. Perioperative mortality was considered the primary outcome. Multivariate logistic regression models were fitted to assess the impact of PHTN on in-hospital mortality. RESULTS: We identified 670,516 entries for TKA and 360,119 for THA. Of those patients, 2184 (0.3%) and 1359 (0.4%), respectively, had the diagnosis of PHTN (average annual rate of 1180 for TKA [range, 507–2073] and 739 for THA [range, 467–1054]). Patients with PHTN undergoing THA experienced an approximately 4-fold increased adjusted risk of mortality (2.4% vs 0.6%), and those undergoing TKA a 4.5-fold increased adjusted risk of mortality (0.9% vs 0.2%) compared with patients without PHTN in the matched sample (P < 0.001 for each comparison). Patients with primary PHTN undergoing THA experienced the highest mortality rate (5% [95% CI, 2.3%–7.7%]). CONCLUSIONS: This analysis demonstrates that patients with PHTN are at increased risk for perioperative mortality after THA and TKA.

Mortality of patients with respiratory insufficiency and adult respiratory distress syndrome after surgery: the obesity paradox.

Introduction: Obesity has long been considered a risk factor for the development of various pathologies, yet evidence supporting increased risk of perioperative mortality in obese individuals developing postoperative complications is limited. Therefore, we sought to characterize the demographics of obese and nonobese individuals developing postoperative respiratory insufficiency (RI)/adult respiratory distress syndrome (ARDS) and to quantify the impact of obesity on in-hospital mortality among this patient population utilizing data collected for the Nationwide Inpatient Sample (NIS). Methods: Nationwide Inpatient Sample data for each year between 1998 and 2007 were accessed. Entries were included if they underwent a surgical procedure and had a diagnosis of RI/ARDS following surgery. Patients fulfilling entry criteria were divided into those with and without obesity. In-hospital mortality was the primary outcome. A logistic regression model was fitted to elucidate if obesity was associated with increased odds for the outcome while controlling for age, gender, admission and procedure type, and comorbidity burden. Results: We identified 9 149 030 admissions that underwent the included surgical procedures between 1998 and 2007. Of those, 5.48% had a diagnosis of obesity. The incidence of RI/ARDS was 1.82% among obese and 2.01% among nonobese patients. Obese patients whose postoperative course was complicated by RI/ARDS had a significantly lower incidence of the need for mechanical ventilation (50% vs 55%). In-hospital mortality was significantly lower compared to nonobese patients (5.45% vs 18.72%). For those patients with RI/ARDS requiring intubation, the in-hospital mortality rate was 11% for obese and 25% for nonobese patients. In the multivariate regression analysis, obesity was associated with a 69% reduction in the odds of in-hospital mortality in postoperative patients with RI/ARDS. Conclusion: In our analysis, obesity was associated with a decreased incidence and adjusted odds for in-hospital mortality after surgery. Our results support the emerging concept of the “obesity paradox.”

The bundle "plus": the effect of a multidisciplinary team approach to eradicate central line-associated bloodstream infections.

BACKGROUND:Central line–associated bloodstream infections (CLABSIs) have decreased significantly over the last decade. Further reductions in CLABSI rates should be possible. We describe a multidisciplinary approach to the reduction of CLABSIs. METHODS:This was an observational study of critically ill patients requiring central venous catheters in 8 intensive care units in a tertiary medical center. We implemented a catheter bundle that included hand hygiene, education of providers, chlorhexidine skin preparation, use of maximum barrier precautions, a dedicated line cart, checklist, avoidance of the femoral vein for catheter insertion, chlorhexidine-impregnated dressings, use of anti-infective catheters, and daily consideration of the need for the catheter. Additional measures included root cause analyses of all CLABSIs, creation of a best practice atlas for internal jugular catheters, and enhanced education on blood culture collection. Data were analyzed using the Poisson test and regression. RESULTS:CLABSI, catheter use, and microbiology were tracked from 2004 to 2012. There was a 92% reduction in CLABSIs (95% lower confidence limit: 67.4% reduction, P < 0.0001). Central venous catheter use decreased significantly from 2008 to 2012 (P = 0.032, −151 catheters per year, 95% confidence limits: −277 to −25), whereas peripherally inserted central catheter use increased (P = 0.005, 89 catheters per year, 95% confidence limits: 50 to 127). There was no apparent association between unit-specific Acute Physiology And Chronic Health Evaluation III/IV scores and CLABSI. Three units have not had a CLABSI in more than a year. The most common organism isolated was coagulase-negative staphylococcus. Since the implementation of minocycline/rifampin catheters, no cases of methicillin-resistant Staphylococcus aureus CLABSI have occurred. CONCLUSIONS:The implementation of a standard catheter bundle combined with chlorhexidine dressings, minocycline/rifampin catheters, and other behavioral changes was associated with a sustained reduction in CLABSIs.

Comparison of intramuscular and venous blood pH, PCO(2) and PO(2) during rhythmic handgrip exercise.

Oxygen and acid-base status during exercise is well established for the lungs, large arteries and veins. However, values for these parameters in exercising muscle are less frequently reported. In this study we examined the relationship between intramuscular PO(2), pH, PCO(2) and the comparable venous values during rhythmic isometric handgrip exercise at target levels of 15%, 30% and 45% of maximum voluntary contraction (MVC). A small fiber optic sensor was inserted into the flexor digitorum profundus (FDP) muscle for continuous measurement of intramuscular (IM) PO(2), pH and PCO(2). Venous blood samples were taken from the forearm every minute during each exercise bout. IM pH and PCO(2) were similar to their venous counterparts at baseline, but the difference between IM and venous values increased when exercise exceeded 30% MVC. During exercise at 15% MVC and greater, venous PO(2) declined from 40 to 21 Torr (approximately 5.3 to 2.8 kPa). IM PO(2) declined from 24 to 8 Torr with 15% MVC, and approached 0 Torr at 30% MVC and 45% MVC. IM pH declined rapidly when IM PO(2) reached 10 Torr and continued to decrease with increasing exertion, despite an IM PO(2) near 0 Torr.

Critical Care in Patients Undergoing Lumbar Spine Fusion A Population-Based Study

Background: Data on the utilization of critical care services (CCSs) among patients who underwent spine fusion are rare. Given the increasing popularity of this procedure, information regarding demographics and risk factors for the use of these advanced services is needed in order to appropriately allocate resources, educate clinical staff, and identify targets for future research. Methods: We analyzed hospital discharge data of patients who underwent lumbar spine fusion in approximately 400 US hospitals between 2006 and 2010. Patient, procedure, and health care system-related demographics for those requiring CCS were compared to those who did not. Outcomes such as mortality, complications, disposition status, and hospital charges were compared among groups and risk factors for the utilization of CCS identified. Results: A total of 95 434 entries of patients who underwent posterior lumbar spine fusion surgery between 2006 and 2010 were identified. Approximately 10% of the patients required CCS. On average, patients requiring CCS were older and had a higher comorbidity burden, developed more complications, had longer hospital stays and higher costs, and were less likely to be discharged home compared to non-CCS patients. Risk factors with increased odds for requiring CCS included advanced age, increasing comorbidity burden, increasing surgical invasiveness, and presence of postoperative complications, especially pulmonary. Conclusions: Approximately, 10% of the patients undergoing lumbar spine surgery require CCS. Utilizing the present data, critical care physicians and administrators can identify patients at risk, educate clinical staff, identify targets for intervention, and allocate resources to meet the needs of this particular patient population.

INTRAMUSCULAR PO2 DETERMINED BY NEAR INFRARED SPECTROSCOPY IS AN EARLY INDICATOR OF HEMODYNAMIC INSTABILITY IN A LOWER BODY NEGATIVE PRESSURE MODEL OF HEMORRHAGIC SHOCK

TOWARDS RESOLVING THE CHALLENGE OF SEPSIS DIAGNOSTIC. Thomas Herget* and Thomas Joos . *Merck KGaA, Darmstadt, Germany; NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany Biomarkers have proven to be very useful in clinical conditions such as heart attack, stroke and cancer. There are characteristics linked to sepsis like in blood pressure, body temperature and heart rate. Efforts over the last decade to improve diagnosis for infectious inflammation have been unsuccessful in identifying a single and universal biomarker that provides sufficiently high sensitivity and specificity. In gramnegative septicemia and following major abdominal trauma, the determination of endotoxin continues to be a leading candidate which could become adopted into clinical practice. The importance of endotoxin measurement continues to grow as more clinicians recognize the added value of measuring endotoxin in critically ill patients and with the emergence of major pharmaceutical trials directly targeting endotoxin in the bloodstream. However, hundreds of other candidates potentially serving as biomarker for sepsis have been recently described, e.g. cysteinyl-leukotriene (LTC4) generation, procalcitonin (PCT) and C-reactive protein (CRP). However, none of them fulfils the criteria requested by clinicians, namely being specific and sensitive. The presentation will discuss criteria for a sepsis biomarker, will give an overview of obtaining samples from appropriate cell systems and from patients. Furthermore, tools will be described to identify marker candidates on genetic-, proteinand metabolite level. The integration of these data sets covering e.g. signal transduction, protein : protein interaction, gene expression with the help of bioinformatics and systems biology will help to validate such candidates. The final goal is manufacturing a robust diagnostic device for clinical routine work. A solid sepsis diagnostics method will be beneficial for patients, but also for the healthcare systems and will open challenges for the pharmaceutical industry.

Comparison of the duration of antimicrobial activity of 2 different antimicrobial central venous catheters

We compared the duration of antimicrobial effectiveness of 2 different antimicrobial catheters. The baseline activity of minocycline-rifampin catheters was greater than that of silver-platinum-carbon catheters against Staphylococcus aureus, Staphylococcus epidermidis, and Enterococcus faecalis. The antimicrobial activity of the minocycline-rifampin catheters against these pathogens persisted for up to 12 days, while that of the silver-platinum-carbon catheters was depleted by day 10 (P < .05).