Comparative electrophysiological evaluation of hippocampal function following repeated inhalation exposures to JP-8, Jet A, JP-5, and the synthetic Fischer Tropsch fuel.

Exposure to fuels continues to be a concern in both military and general populations. The aim of this study was to examine effects of in vivo rat repeated exposures to different types of jet fuel utilizing microelectrode arrays for comparative electrophysiological (EP) measurements in hippocampal slices. Animals were exposed to increasing concentrations of four jet fuels, Jet Propellant (JP)-8, Jet A, JP-5, or synthetic Fischer Tropsch (FT) fuel via whole-body inhalation for 20 d (6 hr/d, 5 d/week for 28 d) and synaptic transmission as well as behavioral performance were assessed. Our behavioral studies indicated no significant changes in behavioral performance in animals exposed to JP-8, Jet A, or JP-5. A significant deviation in learning pattern during the Morris water maze task was observed in rats exposed to the highest concentration of FT (2000 mg/m3). There were also significant differences in the EP profile of hippocampal neurons from animals exposed to JP-8, Jet A, JP-5, or FT compared to control air. However, these differences were not consistent across fuels or dose dependent. As expected, patterns of EP alterations in brain slices from JP-8 and Jet A exposures were more similar compared to those from JP-5 and FT. Further longitudinal investigations are needed to determine if these EP effects are transient or persistent. Such studies may dictate if and how one may use EP measurements to indicate potential susceptibility to neurological impairments, particularly those that result from inhalation exposure to chemicals or mixtures.

Indications of Endocrine Disruptor Effects of JP-5 Jet Fuel Using a Rat-Model Reproductive Study and an In Vitro Human Hormone Receptor Assay.

Recent events concerning jet fuel contamination of drinking water have shown that we need a better understanding of the effects of ingested jet fuel. To this end, a reproductive study with ingested jet fuel in rats was undertaken with relatively high concentrations of Jet Propellant (JP)-5 along with a human estrogen receptor activation in vitro assay using JP-5, JP-8, and an alternative jet fuel derived from the camelina plant referred to as HydroRenewable Jet (HRJ) fuel, to help evaluate potential effects of ingested jet fuel. The results of the in vivo study provide evidence that JP-5 can act as an endocrine disruptor, with specific observations including altered hormone levels with JP-5 exposure (significantly lower estradiol levels in male rats and significantly increased Dehydroepiandrosterone levels in females), and a decreased male/female offspring ratio. The in vitro hormone receptor activation assay indicated that JP-5 and JP-8 are capable of upregulating human estrogen receptor (ER) activity, while HRJ was not active in the ER assay. The jet fuels were not able to activate androgen or glucocorticoid receptors in further in vitro assays. These results infer potential endocrine disruption associated with JP-5, with activation of the estrogen receptor as one potential mechanism of action.

Bench study of a new device to display and maintain stable artificial airway cuff pressure.

BACKGROUND: Artificial airway cuff pressure should be maintained within a narrow range. Excessive cuff pressure presents a risk of tracheal damage and stenosis. Insufficient cuff pressure adds the risk of secretion leak past the cuff, tidal-volume leakage, and accidental extubation. The available cuff-inflation devices do not address these problems. OBJECTIVE: In the laboratory I developed and evaluated a new cuff-inflation device that continuously displays the cuff pressure and maintains stable cuff pressure. METHODS: The cuff-inflation device evaluation included: test the manometer accuracy; compare the displayed pressure to the pressure delivered to the pilot balloon; determine the device's response to cuff-pressure changes with the addition of 5 mL or 10 mL of air after achieving a 30 cm H(2)O baseline; measure the V(T) leak in an intubated artificial trachea by comparing the device results to benchmark measurements; and determine the stability of baseline cuff pressure during routine cuff checks. RESULTS: The mean ± SD bias and precision of device's display, compared to the calibration analyzer, was 1.3 ± 2.6 cm H(2)O. The pressure delivered by the cuff-inflation device's gas-sampling line to the pilot balloon was equal to the pressure displayed by the cuff-inflation device. With the cuff-inflation device the cuff pressure was unchanged, compared to baseline, after adding 5 mL or 10 mL of air. With 2 current cuff methods, cuff pressure increased to means exceeding 160 cm H(2)O and 300 cm H(2)O, respectively. Compared to the benchmark, the difference in exhaled V(T) mean ± SD bias and precision were: cuff-inflation device 1.4 ± 4.8 mL, and syringe-inflation method 2.4 ± 6.2 mL. Representing a single cuff pressure check, disconnecting the endotracheal-tube pilot balloon from the cuff-inflation device's gas-sampling line and then reconnecting it had no effect on baseline cuff pressure at 2 seconds or 60 seconds. CONCLUSIONS: The cuff-inflation device demonstrated possible improvements over available cuff-inflation devices and cuff-pressure-control methods.

Submarine exposure guideline recommendations for carbon dioxide based on the prenatal developmental effects of exposure in rats.

BACKGROUND: To protect crewmember health, the U.S. Navy sets exposure limits for more than 200 components of submarine atmospheres. The addition of females to nuclear submarines required a reevaluation of these exposure limits, originally established for all-male crews. In the case of carbon dioxide (CO2 ), the only available data suitable for deriving an exposure limit were from a 2010 study sponsored by the British Royal Navy that reported a debatable interpretation casting doubt on whether current U.S. Navy exposure limits served to protect fetal developmental health. METHODS: About 120 time-mated female Sprague-Dawley rats (Crl: CD[SD]) were exposed to CO2 at levels of 1.5%, 2.0%, 2.5%, and 3.0% from gestation days 6 to 20. Dams were euthanized and fetuses were examined. RESULTS: Findings with implications for exposure limits for CO2 during pregnancy were an increased mean litter proportion of early resorptions and a lower mean litter proportion of viable fetuses in the 3.0% CO2 group. CONCLUSION: The results yield a No Observed Adverse Effect Level (NOAEL) of 2.5% and a Lowest Observed Adverse Effect Level (LOAEL) of 3.0%. The results reasonably allow a point of departure of 2.5% CO2 for deriving an exposure recommendation. An interspecies uncertainty factor was applied to derive a recommended 90-day continuous exposure limit (CEL) of 0.8% for CO2 . As reproductive endpoints that are developmental in nature must be assumed to result from a single exposure at a critical point during gestation, it is further recommended that the 24-hr emergency exposure limit (EEL) also be 0.8%.

Wireless on-demand and networking of Puritan Bennett 840 ventilators for direct data capture.

Manual transcription inaccuracies have been reported to be a frequent occurrence in clinical practice, which has been confirmed in my institution. I explored alternative methods of obtaining data directly from the Puritan Bennett ventilator. The aim of this project was to record all of the ventilator settings and monitored data with wireless technology. I evaluated 2 data-capture methods: on-demand data capture into a personal digital assistant, and continuous ventilator networking with a stand-alone computer. I was successful in both the intensive care unit and laboratory environment in transferring ventilator data, for up to several days, and with a data-capture interval as short as 60 seconds.

Respiratory care billing using a personal digital assistant.

In 2003 I reported how my respiratory care department at Tufts-New England Medical Center developed an inexpensive, in-house, computerized clinical-information-management system, in which the respiratory therapists carry handheld computers during their rounds, entering clinical information into the handhelds as they work and later downloading that information to a database in a desktop computer. Now we have added a billing module to our customized software. This article describes the design, use, and attributes of this billing system, including improved charge-capture, which increased department revenue substantially. Our system has several other important advantages over traditional billing systems.

Development of an affordable data collection, reporting, and analysis system.

Available professionally designed systems for recording, storing, retrieving, and analyzing patient data (such as treatments delivered, laboratory and pulmonary function test results, ventilator settings, and patient assessments) are prohibitively expensive to many hospitals and clinics. At Tufts-New England Medical Center we designed and implemented a computerized patient data management system that uses relatively inexpensive "personal digital assistants" and inexpensive, commonly-available software. Compared to the pen-and-paper flow sheet system we previously used, our computerized system saves time and money, is accurate and user-friendly, and allows data retrieval and analysis that can improve clinical practice and efficiency. We believe our experience could benefit other institutions.