Validation of the firefighter WFI treadmill protocol for predicting VO2 max.

BACKGROUND: The Wellness-Fitness Initiative submaximal treadmill exercise test (WFI-TM) is recommended by the US National Fire Protection Agency to assess aerobic capacity (VO2 max) in firefighters. However, predicting VO2 max from submaximal tests can result in errors leading to erroneous conclusions about fitness. AIMS: To investigate the level of agreement between VO2 max predicted from the WFI-TM against its direct measurement using exhaled gas analysis. METHODS: The WFI-TM was performed to volitional fatigue. Differences between estimated VO2 max (derived from the WFI-TM equation) and direct measurement (exhaled gas analysis) were compared by paired t-test and agreement was determined using Pearson Product-Moment correlation and Bland-Altman analysis. Statistical significance was set at P < 0.05. RESULTS: Fifty-nine men performed the WFI-TM. Mean (standard deviation) values for estimated and measured VO2 max were 44.6 (3.4) and 43.6 (7.9) ml/kg/min, respectively (P < 0.01). The mean bias by which WFI-TM overestimated VO2 max was 0.9ml/kg/min with a 95% prediction interval of ±13.1. Prediction errors for 22% of subjects were within ±5%; 36% had errors greater than or equal to ±15% and 7% had greater than ±30% errors. The correlation between predicted and measured VO2 max was r = 0.55 (standard error of the estimate = 2.8ml/kg/min). CONCLUSIONS: WFI-TM predicts VO2 max with 11% error. There is a tendency to overestimate aerobic capacity in less fit individuals and to underestimate it in more fit individuals leading to a clustering of values around 42ml/kg/min, a criterion used by some fire departments to assess fitness for duty.

Validation of heart rate derived from a physiological status monitor-embedded compression shirt against criterion ECG.

Firefighters are subject to extreme environments and high physical demands when performing duty-related tasks. Recently, physiological status monitors (PSM) have been embedded into a compression shirt to enable firefighters to measure, visualize, log, and transmit vital metrics such as heart rate (HR) to aid in cardiovascular risk identification and mitigation, thereby attempting to improve the health, fitness, and safety of this population. The purpose of this study was to validate HR recorded by the PSM-embedded compression shirt against a criterion standard laboratory ECG-derived HR when worn concurrently with structural firefighting personal protective equipment (PPE) during four simulated firefighting activities. Ten healthy, college-age men (mean ± SD: age: 21 ± 1 yr; body mass: 91 ± 10 kg; body mass index: 26.9 ± 3.1 kg/m(2)) completed four tasks that are routinely performed during firefighting operations: outdoor fast-paced walking (FW), treadmill walking (TW), searching/crawling (SC), and ascending/descending stairs (AD). They wore the PSM-embedded compression shirt under structural firefighting PPE. HR was recorded concurrently by the PSM-embedded compression shirt and a portable metabolic measurement system accompanied with a standard 12-lead electrocardiograph that was used to provide criterion measures of HR. For all four tasks combined there was very high correlation of PSM and ECG HR (r > 0.99; SEE 0.84 /min) with a mean difference (bias) of -0.02 /min and limits of agreement of -0.07 to 0.02 /min. For individual tasks, the correlations were also high (r-values = 0.99; SEE 0.81-0.89). The mean bias (limits of agreement) was: FW 0.03 (-0.09 to 0.14); TW 0.04 (-0.05 to 0.12); SC -0.01 (-0.12 to 0.10); AD -0.13 (-0.21 to -0.04) /min. These findings demonstrate that the PSM-embedded compression shirt provides a valid measure of HR during simulated firefighting activities when compared with a standard 12-lead ECG.

A decade of washing out common bile duct stones with papillary balloon dilatation as a one-stage procedure during laparoscopic cholecystectomy.

BACKGROUND: Laparoscopic cholecystectomy is the treatment of choice for the management of cholecystolithiasis. For the management of choledocholithiasis, a number of options exist. The effectiveness of washing out common bile duct stones with laparoscopic transcystic papillary balloon dilatation (LTPBD) in patients undergoing laparoscopic cholecystectomy (LC) as a one-stage procedure was evaluated. METHODS: Retrospectively, the files of 63 patients treated with LTPBD in a one-stage procedure undergoing laparoscopic cholecystectomy between December 1996 and December 2006 were studied. RESULTS: Fifty-three patients were treated successfully in a one-stage procedure, seven patients were treated in two steps with an endoscopic retrograde cholangiopancreatography (ERCP) postoperatively, and in three cases a conversion to open surgery was required. The median operation time was 128 min, and the median hospital stay was 4 days. No patients developed postoperative pancreatitis. In one case contrast leakage from the common bile duct was detected. It was the only complication directly related to the LTPBD. There were no postoperative deaths. CONCLUSIONS: We consider the wash out of common bile duct stones after LTPBD in a one-stage procedure to be an easy to do and safe operation with great results. Cooperation with an intervention radiologist and application of an angioplastic dilatation dotter balloon catheter are the keys to success in this procedure. In our hospital, it is the treatment of choice for choledocholithiasis associated with cholelithiasis.

Development of a generic method to the solid-phase extraction of acidic compounds from complex matrices.

A mixed-mode solid-phase extraction procedure was developed for the isolation and purification of acidic compounds from complex biological matrices. Urine samples were spiked with several acidic drugs and diluted in ammonium acetate buffer. Isolute HAX columns (a mixed-mode phase consisting of both hydrophobic and ion-exchange ligands) were conditioned with methanol and ammonium acetate prior to sample loading. Once the samples were loaded, the cartridges were rinsed sequentially with ammonium acetate and a 50:50 ratio of methanol and deionized water. The analytes were eluted with an 80:20 ratio of methanol and acetic acid. The eluates were evaporated to dryness and reconstituted to a final volume with a 98:2:0.1 ratio of deionized water, acetonitrile, and trifluoroacetic acid. Samples were analyzed by high-performance liquid chromatography. The absolute recoveries for most of the tested acidic drugs exceeded 80% at an original concentration of 1 microg/mL. Hydrophobic and ion-exchange sorbents were also investigated separately; however, the retention of the analytes suffered during sample application as well as the purity of the eluted extract. Results on anion-exchange columns show that the correct choice of counter-ion is extremely important to the retention of acidic analytes. The highest absolute recoveries were obtained when acetate was the counter-anion on the ion-exchange sorbent.

Rheumatoid disease.

This article documents the developments in surgery for the rheumatoid hand that have been made during the last 40 years and reviews the pertinent literature.

Treatment of respiratory tract infections with pefloxacin in critically ill patients hospitalized in a surgical intensive care unit.

Respiratory tract infections were treated with pefloxacin in fifteen patients, who were hospitalized in the intensive care unit and required artificial ventilation. The treatment was successful in ten patients. Development of resistance was observed in Staphylococcus aureus (two times) and Pseudomonas aeruginosa (four times). No adverse reactions were seen.

An exercise-induced compartment syndrome of the dorsal forearm--a case report.

A 46-year-old male patient experienced extreme pain in the dorsal forearm after strenuous work. He had the classical physical findings of compartment syndrome and elevation of compartment pressure of 45 mm by direct measurement. A decompressive fasciotomy of the dorsal musculature provided total relief of pain, and subsequently full recovery of all function occurred.

In vitro binding and pharmacokinetics of gold salts in plasma proteins and chelating agents.

The binding of sodium aurothiomalate, sodium aurothiosulphate and aurothioglucose to plasma proteins has been investigated in vitro. All gold compounds were bound to protein at a similar rate and had similar apparent affinity constants and binding capacities. Penicillamine (10 or 100 microgram/ml) was unable to chelate significant amounts of bound gold from plasma protein.