High mortality risk of type III monomicrobial gram-negative necrotizing fasciitis: The role of extraintestinal pathogenic Escherichia coli (ExPEC) and Klebsiella pneumoniae.

OBJECTIVES: The aim of this study was to investigate the prognostic value of reclassified new type III monomicrobial gram-negative necrotizing fasciitis (NF) and the microbial factors associated with an increased risk of mortality. METHODS: This study included 235 NF cases treated at National Taiwan University Hospital. We compared the mortality risk of NF caused by different causal microorganisms and examined the bacterial virulence genes profile and antimicrobial susceptibility pattern associated with an increase in mortality risk. RESULTS: Type III NF (n = 68) had a mortality risk two-fold higher than type I (polymicrobial, n = 64) or type II (monomicrobial gram-positive, n = 79) NF (42.6% vs 23.4% or 19.0%, P = 0.019 and 0.002, respectively). Mortality differed by causal microorganism (Escherichia coli [61.5%], Klebsiella pneumoniae [40.0%], Aeromonas hydrophila [37.5%], Vibrio vulnificus [25.0%], polymicrobial [23.4%], group A streptococci [16.7%], and Staphylococcus aureus [16.2%], in decreasing rank, P <0.001). Type III NF caused by E. coli, identified as extraintestinal pathogenic E. coli (ExPEC) via virulence gene analyses, was associated with a particularly high mortality risk (adjusted odds ratio: 6.51, P = 0.003) after adjusting for age and comorbidities. Some (38.5%/7.7%) of the E. coli strains were non-susceptible to third/fourth-generation cephalosporins but remained susceptible to carbapenems. CONCLUSION: Type III NF, especially cases caused by E. coli or K. pneumoniae, are associated with a comparatively higher mortality risk than type I or type II NF. Wound gram stain-based rapid diagnosis of type III NF may inform empirical antimicrobial therapy to include a carbapenem.

Comparison of Hemodynamic and Cerebral Oxygenation Responses during Exercise between Normal-Weight and Overweight Men.

Obesity has negative impacts on cardiovascular function and may increase cerebrovascular complications during exercise. We compared hemodynamic and cerebral oxygen changes during high-intensity exercise between overweight (OW) and normal-weight (NW) individuals. Eighteen NW and fourteen OW male individuals performed high-intensity (70% of peak oxygen uptake, VO2peak) cycling exercises for 30 min. Hemodynamics were measured using a bioelectrical impedance device, and cerebral oxygenation status was measured using a near-infrared spectrophotometer during and after exercise. The VO2peak of NW individuals was significantly higher than that of OW individuals (41.3 ± 5.7 vs. 30.0 ± 5.0 mL/min/kg, respectively; p < 0.05). During the 30 min exercise, both groups exhibited an increase in oxygenated hemoglobin (O2Hb) (p < 0.001), deoxygenated hemoglobin (p < 0.001), and cardiac output with increasing time. Post-exercise, cardiac output and systemic vascular resistance were significantly higher in the OW group than in the NW group (p < 0.05). The O2Hb in the NW group was significantly higher at post-exercise times of 20 min (13.9 ± 7.0 µmol/L) and 30 min (12.3 ± 8.7 µmol/L) than that in the OW group (1.0 ± 13.1 µmol/L and 0.6 ± 10.0 µmol/L, respectively; p = 0.024 vs. 0.023, respectively). OW participants demonstrated lower cerebral oxygenation and higher vascular resistance in the post-exercise phase than non-OW subjects. These physiological responses should be considered while engaging OW and obese individuals in vigorous exercise.

Aerosol Delivery Using Jet Nebulizer and Vibrating Mesh Nebulizer During High Frequency Oscillatory Ventilation: An In Vitro Comparison.

BACKGROUND: High frequency oscillatory ventilation (HFOV) is used in critically ill patients with severe hypoxemic respiratory failure. The purpose of this in vitro study was to determine the efficiency of aerosol delivery with different lung parameters during simulated neonatal, pediatric, and adult HFOV. METHODS: Sensormedics 3100A/B ventilators were used to deliver infant, pediatric, and adult HFOV. Two types of aerosol generators were chosen for testing: 1) a continuous jet nebulizer (JN) with a unit-dose of 5.0 mg/2.5 mL salbutamol sulfate diluted into 4 mL, and 2) a vibrating mesh nebulizer (VMN) with salbutamol sulfate were run to completion of aerosol generation. Both aerosol devices were placed 1) between the ventilator circuit and the endotracheal tube (ETT) (proximal position); and 2) at the inlet of the heated humidifier (distal position) (n = 5). Drug was collected on a bacterial filter placed distal to the ETT, and the drug eluted and analyzed with a UV Spectrophotometer at 276 nm. T- test and ANOVA tests were used for comparison (p < 0.05). RESULTS: The inhaled drug delivered by JN was 0%-0.6% of the nominal dose when placed at distal position, and 0%-3% at proximal position (p < 0.01), while the VMN was 0%-0.5% at distal and 8.6%-22.7% at proximal position (p < 0.01). Aerosol delivery during HFOV was greater with adult settings than pediatric and infant settings with VMN and JN (22.7%, 8.6%, and 17.4% respectively, p < 0.01). When the aerosol delivery device was placed at the distal position, negligible drug mass was observed (<0.5%), regardless of the nebulizer device used. CONCLUSIONS: During HFOV, aerosol delivery with the nebulizer placed at proximal was greater than placement distal from the ETT, with VMN delivering more drug than JN. The inhaled drug was delivery correlated positively with ETT size, MAP, and bias flow, and inversely proportional to power settings.