Verification of an intravenous fluid warmer: A prospective, two-center observational trial.

Objectives: Avoiding inadvertent hypothermia during surgery is important. Intravenous fluid warmers used intraoperatively are critical for maintaining euthermia. We sought to prospectively evaluate the performance of the parylene-coated enFlow™ intravenous fluid warmer in patients undergoing surgery. Methods: This was a prospective two-center observational clinical trial performed in inpatient surgical services of two large academic hospital systems. After written informed consent, patients were enrolled in the trial. All patients were adults scheduled for a surgery that was expected to last for at least 1 h with the administration of at least 1 L of fluid warmed prior to infusion. Patient temperature was recorded in the preoperative unit, at the induction of anesthesia, and then every 15 or 30 min until the end of surgery. Temperature monitoring continued in the recovery unit. The parylene-coated enFlow™ intravenous fluid warmer was used in addition to the usual patient warming techniques. The primary outcome was the average core temperature, and secondary analyses assessed individual temperature measurements, temperature measurements during specific time periods, and rate of hypothermic events. Results: In all, 50 patients (29 males) with a mean age of 64 years were included in the analysis. The mean surgical time was 195 min and patients received an average of 1142 mL of fluids. Core temperature dropped by only 0.3°C approximately 60 min after induction and recovered back to the baseline level approximately 60 min later. There was no correlation between flow rate and measured core body temperature. Conclusions: The parylene-coated enFlow intravenous fluid warmer was able to warm fluids at all flow rates during prolonged surgery. The results showed that enFlow performed as expected.

Levels of leachable elements from long-term use of enFlow fluid warmer.

Objective: In the delivery of intravenous fluids, in-line warming devices frequently transfer heat using a metal heating plate, which if uncoated can risk elution. This bench study examined extractable elements detected following long-term use of the parylene-coated enFlow® Disposable IV/Blood Warmer. Methods: We tested 16 clinically relevant challenge fluids typical of the surgical setting, including commercially available single donor blood and blood products as well as intravenous saline and electrolyte solutions. After 72 h of warming at 40°C (104°F) via the enFlow, analytical chemistry identified and quantified the most clinically significant extractable elements (arsenic, barium, cadmium, copper, and lead) to estimate chemical exposure. We also measured the extracted concentrations of these five elements following simulated use of the device with three solutions (Sterofundin ISO, Plasma-Lyte 148, and whole blood) that were pumped through the warmed device at two different flow rates (0.2 and 5.5 mL min-1). Results: Across all scenarios of acute and long-term exposures for different populations, the enFlow demonstrated low toxicological risks as measured by the calculation of tolerable exposure for extracted arsenic, barium, cadmium, copper, and lead. Conclusion: The results suggest biological safety for the use of parylene-coated enFlow with a variety of intravenous solutions and in different therapeutic scenarios.

Impact of parylene coating on heating performance of intravenous fluid warmer: a bench study.

BACKGROUND: Perioperative hypothermia is a common occurrence, particularly with the elderly and pediatric age groups. Hypothermia is associated with an increased risk of perioperative complications. One method of preventing hypothermia is warming the infused fluids given during surgery. The enFlow™ intravenous fluid warmer has recently been reintroduced with a parylene coating on its heating blocks. In this paper, we evaluated the impact of the parylene coating on the new enFlow's fluid warming capacity. METHODS: Six coated and six uncoated enFlow cartridges were used. A solution of 10% propylene glycol and 90% distilled H2O was infused into each heating cartridge at flow rates of 2, 10, 50, 150, and 200 ml/min. The infused fluid temperature was set at 4 °C, 20 °C, and 37 °C. Output temperature was recorded at each level. Data for analysis was derived from 18 runs at each flow rate (six cartridges at three temperatures). RESULTS: The parylene coated fluid warming cartridge delivered very stable output of 40 °C temperatures at flow rates of 2, 10, and 50 ml/min regardless of the temperature of the infusate. At higher flow rates, the cartridges were not able to achieve the target temperature with the colder fluid. Both cartridges performed with similar efficacy across all flow rates at all temperatures. CONCLUSIONS: At low flow rates, the parylene coated enFlow cartridges was comparable to the original uncoated cartridges. At higher flow rates, the coated and uncoated cartridges were not able to achieve the target temperature. The parylene coating on the aluminum heating blocks of the new enFlow intravenous fluid warmer does not negatively affect its performance compared to the uncoated model.

Observation of Aerosol Generation by Human Subjects During Cardiopulmonary Exercise Testing Using a High-Powered Laser Technique: A Pilot Project.

Purpose: Human respiratory aerosols may have important implications for transmission of pathogens. The study of aerosol production during vigorous breathing activities such as exercise is limited. In particular, data on aerosol production during cardiopulmonary exercise testing (CPET) are lacking. Methods: In this pilot project, we used a high-powered, pulsed Nd:YAG laser to illuminate a region of interest in front of two healthy adult subjects during CPET. Subjects exercised to the point of respiratory compensation. Images were captured with a high-speed, high-resolution camera to determine net exhaled particle (NEP) counts at different phases of CPET, including resting breathing, submaximal exercise, peak exercise, and active recovery. Experiments were performed with the room ventilation activated. Results: Net exhaled particle counts remained relatively constant until late/peak exercise when they decreased prior to rebounding into recovery. NEP counts at resting breathing were higher than those reported using other methods of measurement. Exhaled particles were in the submicron size range. Conclusion: Our method of aerosol particle quantification enables measurement of significant quantities of ultrafine particles and dynamic assessment of aerosol production during CPET. The unique pattern of aerosol production observed during submaximal and peak exercise suggests that extension of results from resting breathing to CPET may not be appropriate.

Fluid warming with parylene-coated enFlow cartridge: Bench and pilot animal study of aluminum extraction due to prolonged use.

OBJECTIVES: Intravenous fluid warming devices with surface heating systems transfer heat using aluminum blocks, which if uncoated elute toxic levels of aluminum into the infusate. This study examined extractable aluminum detected from prolonged use of the updated version of the enFlow® cartridge, which uses a parylene-coated aluminum heating block. METHODS: In dynamic bench tests, we measured the concentration of aluminum that leached into three solutions (Sterofundin ISO, Plasma-Lyte 148, and whole blood) that were continuously pumped (0.2 and 5.5 mL min-1) and warmed to 40°C by the enFlow cartridge (parylene-coated) for 5 h. Prolonged quasi-static bench tests measured aluminum concentration in 16 solutions which were gently rocked within the enFlow cartridge (parylene-coated) for 72 h at 40°C. Aluminum concentrations were measured using inductively coupled mass spectroscopy and matrix blank corrected. Measured aluminum concentrations were compared to a Tolerable Exposure limit to calculate Margins of Safety based on the US Food and Drug Administration maximum recommended concentration in parenteral fluids (25 µg L-1). A parallel pilot in vivo animal study was performed using mice injected with fluids warmed for 72 h by the enFlow cartridge (parylene-coated). RESULTS: The enFlow cartridge (parylene-coated) demonstrated low toxicological risks in all tests. Sterofundin ISO resulted in the highest aluminum concentration after simulated prolonged use of the enFlow cartridge (parylene-coated) (3.11 µg device-1), which represents a 99.2% decrease from the enFlow cartridge (uncoated) and Margin of Safety of 1.7. Dynamic tests at two different flow rates with three challenge solutions resulted in concentrations less than the method detection limits (20.6 or 41.2 µg L-1) of the analysis method. The animals in the in vivo study showed no evidence of toxicity. CONCLUSION: Observed toxicological risk levels associated with the enFlow cartridge (parylene-coated) intravenous fluid warmer were below those set by the Food and Drug Administration and suggest that the use of enFlow cartridge (parylene-coated) is safe with a variety of intravenous solution types and in different therapeutic scenarios.

Violent victimization of women and men: physical and psychiatric symptoms.

BACKGROUND: Our objectives for this exploratory study were (1) to assess the prevalence in a family practice of violent victimization of women and men by partners, friends, families, and strangers, and (2) to compare the physical symptoms, depression, alcohol use problems, and social support of women and men who were or were not victimized in the previous 12 months. METHODS: We conducted a cross-sectional, multicenter study of family practice patients (1999-2000). One-thousand twenty-four patients, including 679 women and 345 men from 18 to 64 years of age completed a standard health history and a demographic questionnaire. The health history questionnaire included a question about violent victimization. RESULTS: Violent victimization was reported by 9.9% of the women and 10.9% of the men. Patients who were victimized were grouped into those who were victimized by partners (4.9% of women and 3.0% of men); by friends, or family, or strangers (2.3% of women and 5.0% of men); or by more than one category of persons other than partners (2.6% of women and 3.0% of men). Almost one third of patients victimized by partners were also victimized by another person. Women who were victimized had more physical symptoms than women who were not victimized. Women who were victimized and men who were victimized by their partners had more depressive symptoms than other women and men. Patients who were victimized by more than one category of other victimizers reported more alcohol use problems than other patients. Patients who were victimized reported less social support than patients who were not victimized. CONCLUSIONS: Both women and men report violent victimization in response to a screening question. Violence by partners and by others is related to physical and psychiatric symptoms in women and in men.