Portable Oxygen Research Articles

Development of a compact optical sensor for real-time, breath-by-breath detection of oxygen

The detection of oxygen in breath is of central importance to investigations of metabolism and respiration in both clinical and athletic performance monitoring applications. This paper reports the development of a portable, lightweight optical oxygen sensor that is intended to provide a breath oxygen monitoring solution that is deployable outside a laboratory environment. The sensing methodology is based on the detection of changes in the fluorescence emission of an oxygen-sensitive fluorescent dye. The novelty of the system stems from the humidity-insensitive nature of the oxygen sensor, the highly efficient and compact optical configuration and the use of a novel, wearable control unit based on DSP circuitry. These components combine to provide a portable breath oxygen monitor that can detect changes in the in-breath O2 concentration profile in real-time over a broad range of breathing rates in situations of both rest and exercise. The reported system is expected to have a significant impact on point-of-care (POC) breath-based diagnostics and high performance athletic monitoring.

일체화된 Aperture 구조의 한계전류형 산소센서의 제작 및 특성

Monolith aperture-type oxygen sensors with simple structure of YSZ(pin-hole)/Pt/ YSZ(solid electrolyte)/Pt were fabricated by co-firing technique. To enhance the yield of productivity, a couple of YSZ green sheets for diffused barrier and solid electrolyte were prepared by tape-casting and co-firing method. The limit current characteristics of the oxygen sensors were measured between 500 and <TEX>$650^{\circ}C$</TEX> The heating temperature of <TEX>$600^{\circ}C$</TEX> was optimum as a portable oxygen sensor in the range of oxygen concentration from 0 to 75 vol%. Linear proficiency of limit current behavior as a function of oxygen concentration was controlled by the variation of aperture dimension. The fabricated oxygen sensors showed the stable sensing output for 30 days. Gas leakage in bonding area due to warping, cracking and thermal cycling was not found in the period.

Validity of physical activity monitors in adults participating in free-living activities

BackgroundFor a given subject, time in moderate to very vigorous intensity physical activity (MVPA) varies substantially among physical activity monitors.ObjectiveIn the present study, the primary objective, whether time in MVPA...

TOPICAL OXYGEN THERAPY INDUCES VASCULAR ENDOTHELIAL GROWTH FACTOR EXPRESSION AND IMPROVES CLOSURE OF CLINICALLY PRESENTED CHRONIC WOUNDS

1. Chronic wounds, especially in diabetics, represent a serious threat to human health. 2. Correcting a compromised state of tissue oxygenation by the administration of supplemental O(2) is known to benefit wound healing. Beyond its role as a nutrient and antibiotic, O(2) supports wound healing by driving redox signaling. 3. Hyperbaric oxygen (HBO) therapy is widely used and approved by Center for Medicare and Medicaid Services to treat specific ulcerations. The current literature supports the notion that approaches to topically oxygenate wounds may be productive. 4. Here, we present the results of two simultaneous studies testing the effects of HBO and portable topical oxygen (TO) therapies. These two therapeutic approaches have several contrasting features. 5. In total, 1854 patients were screened in outpatient wound clinics for non-randomized enrolments into the HBO (n = 32; 31% diabetic) and TO (n = 25; 52% diabetic) studies. 6. Under the conditions of the present study, HBO treatment seemed to benefit some wounds while not benefiting others. Overall, HBO did not result in statistically significant improvements in wound size in the given population over the time monitored in the present study. 7. However, TO significantly improved wound size. Among the three O(2)-sensitive genes (VEGF, TGFbeta1 and COL1A1) studied in wound edge tissue biopsies, TO treatment was associated with higher VEGF165 expression in healing wounds. Expression of the other genes mentioned was not affected by TO. There was no significant change in the expression levels of any of genes studied in patients in the HBO study. This establishes a link between VEGF gene expression and healing outcome for TO therapy. 8. Taken together, the present study provides evidence demonstrating that TO treatment benefits wound healing in patients suffering from chronic wounds. Treatment with TO is associated with an induction of VEGF expression in wound edge tissue and an improvement in wound size.

In Case of Emergency, Break Out Exit Plan

In Case of Emergency, Break Out Exit Plan

Validity Of SenseWear™ Pro2 Armband For The Assessment Of Moderate To Very Vigorous Intensity Physical Activity In Free Living Adults.

PURPOSE: Current physical activity guidelines encourage people to accumulate a minimum of 30 minutes of moderate physical activity five days a week or vigorous intensity physical activity for a minimum of 20 minutes three days a week. For a given subject the measured time in moderate to vigorous intensity varies substantially among physical activity monitors and software used. SenseWear™ Pro Armband (BodyMedia Inc., Pittsburgh, PA, USA (Armband)) is currently available but has not yet been satisfactory validated against indirect calorimetry in a free living situation. The aim of the present study was to examine the validity of Armband in assessing moderate to very vigorous intensity physical activity in a free living situation in adults. METHODS: 14 men and six women (21-57yrs) wore Armband and a portable oxygen analyzer (Metamax II, Cortex Biophysic, Leipzig, Germany) for 120 minutes doing various activities. Resting metabolic rate (RMR) was measured with indirect calorimetry according to international guidelines. The cut off points defining moderate, vigorous and very vigorous intensity were 3, 6 and 9 times RMR. The data from the Armband was downloaded and analysed with software developed by the manufacturer (Innerview Professional Research Software Version 5.1). Individual Armband data was compared minute by minute (points) with energy expenditure measured with the oxygen analyzer and accumulated into the three intensity categories. Summary of RESULTS: Armband significantly overestimated moderate intensity by 0.15 kcal·min−1 (p=0.02) and underestimated very vigorous intensity by 4.37 kcal·min−1 (p=0.0006). The proportion of points underestimating very vigorous physical activity was 0.92. The underestimation of vigorous intensity, although of 1.90 kcal·min−1, was not statistically significant (p=0.2). CONCLUSIONS: Armband overestimates moderate and underestimates very vigorous intensity compared to indirect calorimetry in a free living situation in adults. When comparing time in moderate to very vigorous intensity among studies it is essential to consider type of physical activity monitor and software.

Comparing supplementary oxygen benefits from a portable oxygen concentrator and a liquid oxygen portable device during a walk test in COPD patients on long-term oxygen therapy

Differences in oxygen delivery between portable oxygen concentrators (POC) and liquid oxygen (LO) portable units, pose a question if POCs are equally effective as LOs in reducing exercise-induced hypoxaemia. Randomized, single-blind clinical trial. Thirteen COPD patients (means: age 66+/-11 year, FEV(1) 35.2+/-13.7% predicted) and respiratory failure (means: PaO2 52+/-5mmHg, PaCO2 51.3+/-7.5mmHg). All patients underwent a series of 6-min walk tests (6MWT) carried out in random order among one of the three devices: POC, LO cylinder and cylinder with compressed air (CA). Oxygen supplementation was 3lpm for LO and an equivalent to 3lpm in a pulse flow system for POC. The mean SpO2 was equally improved at rest: 92.9+/-2.8% with POC and 91.7+/-2.0% with LO compared to CA-87.8+/-2.7% (POC and LO vs. CA p<0.05). POC and LO significantly improved oxygenation during 6MWT (mean SpO(2) was 84.3+/-5% and 83.8+/-4.2%, respectively) compared to breathing CA-77.6+/-7.4%, p<0.05. Mean 6MWT distance increased with LO (350+/-83m) and POC (342+/-96m) when compared to CA (317+/-84m), however, these differences were not statistically significant. Dyspnoea score assessed at the end of the exercise (Borg scale) was significantly lower when breathing oxygen (4.2+/-1.2 with POC and 4.1+/-1.7 with LO vs. 5.4+/-1.9 with CA, p<0.05). Effectiveness of oxygen supplementation from a POC did not differ from the LO source during 6MWT in COPD patients with respiratory failure. Oxygen at 3lpm flow was not sufficient to prevent hypoxaemia during strenuous exercise.

En-Route Care in the Air: Snapshot of Mechanical Ventilation at 37,000 Feet

En-route care necessitates the evacuation of seriously wounded service members requiring mechanical ventilation in aircraft where low light, noise, vibration, and barometric pressure changes create a unique clinical environment. Our goal was to evaluate ventilatory requirements, oxygenation, and oxygen use in flight and assess the feasibility of a computer interface in this austere environment. A personal computer was integrated with the pulse oximeter and ventilator data port used in aeromedical evacuation from Iraq to Germany. Ventilator settings, inspired oxygen (FiO2), tidal volume (VT), respiratory rate (RR), minute ventilation (VE), monitored values, heart rate (HR), and oxygen saturation (SpO2), were recorded continuously. Oxygen use was determined using the equation ([FiO2 - 21]/79) x (MVE). Additional data were obtained through the United States Air Force (USAF) Transcom Regulation and Command/Control Evacuation System (TRAC2ES) and the United States Army Institute of Surgical Research Joint Theater Trauma Registry databases. During a 4 month time frame 117 hours of continuous recording was accomplished in 22 patients. Mean age was 27 +/- 9.83 and injury severity score military was 31.75 +/- 20.63 (range, 9-75). All patients survived transport. Mean values for ventilator settings were FiO2 (24-100%) of 49% +/- 13%, positive end-expiratory pressure of 6 +/- 2.5 (range, 0-17 cm H2O), RR of 15 +/- 2.4 (range, 10-22 breaths/min), and VT of 611 +/- 75 (range, 390-700 mL). Delivered VT in mililiter per kilogram was 6.9 +/- 1.30 and VE was 9.1 L/min +/- 1.4 L/min. Oxygen requirements for desired FiO2 and VE resulted in a mean oxygen usage of 3.24 L/min +/- 1.87 L/min (range, 1.6-10.2 L/min). There were 32 changes to FiO2, 18 changes to PEEP, 26 changes to RR, and 20 changes to VT during flight. Five patients under-went no recorded changes in flight. Three desaturation events (<90%) were recorded lasting 35, 115, and 280 seconds. Recorded ventilatory changes averaged less than 1 (0.82) per hour of recorded flight with FiO2 being the most common. A computer interface is feasible in the austere aeromedical environment. Implications to military operations and civilian homeland defense include understanding casualty oxygen requirements for resource planning in support of aeromedical evacuation. Portable oxygen generation systems may be able to provide adequate oxygen flow for transport, reducing the need for compressed gas. Future studies of oxygen conservation systems including closed loop control of FiO2 are warranted.

Influencia de las técnicas de ahorro energético sobre la saturación de oxígeno en paciente con EPOC portador de oxígeno líquido

We present the case of a 76-year-old male diagnosed of severe chronic obstructive pulmonary disease (COPD) in chronic respiratory insufficiency phases with home oxygen-therapy criteria, carrier of a portable oxygen therapy system. During exercise he presented desaturation that seriously limited all of his daily life activities. The patient was included in a respiratory rehabilitation program consisting of health care education, respiratory physical therapy, physical exercises and occupational therapy with energy saving techniques.In order to evaluate his disability, he underwent a 6 minute walking test that showed desaturation to the effort that was partially corrected when he was administered supplementary oxygen while performing it. The patient was revalued with the same test twice: one with supplementary oxygen applying energy saving techniques and other one of free walking guided by the dyspnea sensation. The analysis of the data obtained in this patient revealed that the desaturation was corrected only when energy saving techniques were used for the walking.

Effects of Cane Versus Walking With a Wheeled Walker on Energy Cost, Distance Traveled and Perceived Exertion in MS Patients

Fatigue is one of the most disabling symptoms of Multiple Sclerosis. Ambulatory individuals with MS typically use assistive devices to lessen the energy cost of walking (Cw), which is commonly used as an index of fatigue in this population. PURPOSE: The purpose of this study was to compare Cw, distance traveled, and perceived exertion during walking with a wheeled walker versus walking with a cane in MS patients. METHODS: 13 MS patients, including five males aged 49.0 ± 5.6 yrs. and eight females aged 52.6 ±7.8 yrs., were recruited from a local MS clinic. Experimental conditions included walking on a smooth, 30.5 m long, low friction surface with the assistance of a wheeled walker in one trial and with the assistance of the subject's own cane in the other trial. Trial order was randomized with a rest period in between. Cw was determined as the difference between average oxygen consumption while walking minus average oxygen consumption at rest divided by walking velocity (ml/kg/m). Oxygen consumption was measured using a portable oxygen consumption unit. Perceived exertion was rated using the Borg scale, and distance traveled was measured to the nearest centimeter. Paired t-tests were performed to evaluate differences in Cw, RER, HR, VO2, Ve, RPE and distance walked across the walking conditions. RESULTS: Walking with the wheeled walker resulted in significantly lower energy cost of walking (16%) than walking with a cane (p < 0.05). The distance walked was also significantly greater in the wheeled walker vs cane trial (104.2 ± 19.1 vs 93.0 ± 25.7) and perceived exertion was significantly lower in the wheeled walker condition (p < 0.01). CONCLUSIONS: Use of a wheeled walker lowers the energy cost of walking, enabling walking greater distance with less perceived exertion among ambulatory individuals with MS. This could translate to increased participation in activities of daily living such as going to a shopping mall, which, in turn, could reduce de-conditioning and increase opportunities for social interaction.

Oxygen Consumption and Energy Expenditure of Different Intensities of Weight-Training in Women

Few studies have examined the oxygen consumption and energy expenditure of weight training performed at different exercise intensities, but with similar exercise volumes, in women. PURPOSE: Therefore, the purpose of this study was to compare the total oxygen consumption (exercise + recovery between sets) and energy expenditure of multi-set, circuit weight training at different intensities (but same volume) in women. METHODS: Oxygen consumption (VO2, ml/min) was measured at rest, during weight training (WT), and during one-minute recovery periods between WT sets with a portable oxygen collection device (COSMEDTM K4b2) in nine women (age = 20.5 +/− .8 yr). Subjects performed at least three successive sets (separated by 1 min rest) of a seated chest press, supine leg press and a seated lat pull down at two intensities (70% and 85%) of maximum voluntary contraction (MVC) on two nonconsecutive days. The intensity and exercise sequence of the WT sessions was randomized and the sessions were separated by at least 48 hours. Total exercise volume, i.e., total pounds lifted (lbs x repetitions), was determined and held constant across intensities of WT so that only the intensity of work varied. Total exercise VO2 was determined as the oxygen consumption of all WT sets and all one-minute rest periods between sets. Net exercise VO2 (total exercise VO2 - rest VO2) and exercise energy expenditure (total exercise VO2 x 5 kcal/L O2) were calculated. RESULTS: There were no significant differences in the net exercise VO2 (7.5 +/− 2.1 vs. 8.0+/− 1.4L/min, P = .12) or energy expenditure (37.3 +/− 10.7 vs. 40.4+/− 7.4 kcal, P = .12) of WT at 70% versus 85% MVC. CONCLUSIONS: In women, total exercise oxygen consumption and energy expenditure appear to be similar across different intensities of WT when the total exercise volume (pounds lifted) is the same across WT intensities.

Polymer membrane air separation performance for portable oxygen enriched combustion applications

The topic of air separation is studied for portable power system applications. Air separation is of interest for controlling and optimizing the combustion characteristics in a liquid fuel burner. In particular, polymeric membranes are investigated for their performance in supplying oxygen enriched air to a small burner. The air separation performance of perfluorodioxole polymer membranes is measured, and the relationship between membrane performance and combustion parameters is investigated. The feasibility of using such membranes for burner based power system applications is demonstrated and appears to be promising. The power draw necessary to achieve prescribed flow and performance was measured and found to be relatively low. A dimensionless enrichment number is defined, and a membrane figure of merit is introduced.

Efficacy of the 6-Minute Walk Test in Evaluating Ambulatory Oxygen Therapy

To compare oxyhemoglobin saturation (SpO2) observed during the 6-minute walk test with that of pulse oximetry carried out during activities of daily living (ADLs). The efficacy of the 6-minute walk test for determining adequate oxygen flow to prevent arterial desaturation during ADLs was also analyzed. We studied 37 patients diagnosed with chronic obstructive pulmonary disease (COPD)--mean (SD) forced expiratory volume in 1 second, 26% (9%) of predicted--and compared SpO2 values obtained in the 6-minute walk test with those obtained with ambulatory pulse oximetry during ADLs. Eleven of the 20 patients with exercise-induced desaturation agreed to use portable liquid oxygen and were randomized to ambulatory pulse oximetry on 2 consecutive days, both with and without the administration of oxygen. Oxygen flow was adjusted on successive 6-minute walk tests until a mean SpO2 greater than 85% was reached. The mean SpO2 for all patients was 84% (7%) during the 6-minute walk test and 89% (4%) during ADLs (P<.001). Cumulative percentages of time with SpO2 less than 90%, 88%, and 85% were higher during the 6-minute walk test than during ADLs (P<.001). During the walk test, desaturation was detected in 27% of patients, but was not confirmed by ambulatory pulse oximetry during ADLs. In the subgroup of 11 patients using portable liquid oxygen no significant differences were found between SpO2 values recorded during the walk test and during ADLs with the appropriate oxygen flow. The 6-minute walk test is an effective method for detecting desaturation during ADLs and for establishing the oxygen flow needed to correct exercise-induced desaturation.

2005 Creative writing contest honorable mention

2005 Creative writing contest honorable mention

A Comparison of Manual and Mechanical Ventilation in Terms of the Adequacy of Ventilation during Intrahospital Transport of Neurosurgical Patients in the Immediate Postoperative Period

Background: Ambu-bags and portable ventilators can provide intubated patients with ventilation during intrahospital transport, where it is desirable to maintain normocarbia. This study was designed to compare the amount of variation in ventilation that occur during the intrahospital transport of neurosurgical patients ventilated either manually or with a portable ventilator. Methods: 40 patients were randomized to receive either manual ventilation (Group A, n = 20) during transport or ventilation by a portable ventilator (Group P, n = 20) during the immediate postoperative period. In group A, an adult laerdal resuscitator bag with a reservoir bag (2,600 ) was used and oxygen (15 L/min) was supplied from a portable oxygen tank. In group P, a portable ventilator was set to controlled mechanical ventilation or synchronized intermittent mandatory ventilation mode, 8.5-10 /kg of tidal volume, 1：2 of inspiratory to expiratory ratio, and 100% oxygen concentration. Respiratory rates were adjusted to maintain normocarbia. Hemodynamic parameters were recorded before and during transport. Arterial blood gas levels were also obtained before and during transport. Results: during transport was significantly lower in Group A than in Group P (P ＜ 0.05). Manually ventilated patients showed greater deviations from normocarbia (35-45 mmHg) than mechanically ventilated patients (P ＜ 0.01). during transport was no different in the two groups. Blood pressure and heart rates during transport increased significantly in both groups versus before transport (P ＜ 0.01). Conclusions: The use of a portable ventilator can effectively maintain normocarbia and produce the stable ventilatory pattern during the intrahospital transport of neurosurgical patients during immediate postoperative period.

The Effect of an 18-Hour Electrical Power Outage on an Urban Emergency Medical Services System

Objectives. To describe the experience of an urban, commercial ambulance provider during the multistate August 2003 electrical power outage (EPO) andto identify how such an event can affect an emergency medical services (EMS) system. Methods. Data were abstracted from all dispatch andprehospital medical records generated during the 18-hour EPO. An hour-by-hour comparison was made between the median number of hourly EMS dispatches during the month of August 2003 andthe total number of hourly EMS dispatches during the EPO. Presenting complaints were categorized, andall calls related to the EPO were identified. Results. During the first ten hours of the EPO, hourly call volume increased an average of 250% (range 50%–500%) as compared with all of August 2003. The greatest increase in call volume occurred during the first seven hours of the EPO. During the EPO, 16% (n = 13) of patients presented with a heat-related complaint precipitated by the failure of air conditioning. In the same period, 37% (n = 31) of patients presented with a respiratory-related complaint, 52% (n = 16) of which were precipitated by the failure of home respiratory equipment such as ventilators, nebulizers, andoxygen concentrators. During the EPO, the average time spent on scene with patients increased 63%, from 11 to 18 minutes, when compared with the time spent 16 hours immediately prior and14 hours immediately after the EPO. Average response andtransport times did not change. Conclusion. Loss of power can cause a dramatic but short-term increase in call volume andlead to a disaster-like situation. EMS resources may be conserved by proactively assisting patients with home medical devices before they develop emergent conditions. Such a patient population might benefit, for example, from home deliveries of portable oxygen tanks or from the creation of temporary facilities that provide a climate-controlled environment andelectrically powered medical devices. Key words: power outage; acute respiratory; emergency medical services; disaster preparedness; environmental emergency.

Physiological and Biomechanical Responses While Running With and Without a Stroller

1716 PURPOSE: This study examined the effects of running with a jogging stroller. The hypothesis was that running with a stroller for 30 minutes would shorten stride length and increase physiological indices of exercise. METHODS: This was a repeated measures design. Five males (38.3 ± 9 years, 72.2 ± 7.4 kg, and 174 ± 13.9 cm) and 5 females (31.8 ± 6.9 years, 59.2 ± 8.2 kg, and 161.8 ± 4.7 cm) performed a graded exercise test on a treadmill and two field tests on a 400m all-weather outdoor track. VO2, heart rate, and ventilation were collected with a Cosmed K4b2 portable oxygen analyzer and lactate was analyzed with a YSI 1500 Sport Lactate Analyzer. The first field test involved running at 75% VO2max for 30 minutes without a stroller and the second involved running at the same intensity with the stroller. Reflective markers were placed on the heels of the participants and video was captured in the sagittal plane. Stride length was evaluated using the Peak Motus system. All field test data was collected at pre-exercise, 10 and 30 minutes RESULTS: A 2×3 repeated measures ANOVA was used to assess differences. Significance was set at 0.05 for all comparisons. The Bonferroni approach was used to control for Type I error across pairwise comparisons. No differences for VO2 or stride length were evident between or during trials. The following variables significantly increased from 10 to 30 minutes while running with the stroller: heart rate (165.7 ± 14.7, 176.3 ± 15.6 b/min; p = .0001), lactate concentration (3.6 ± 1.0, 4.9 ± 1.6 mmol; p = .025), ventilation (93.9 ± 20.7, 104.4 ± 25.6 l/min; p = .009), and RPE (13.5 ± 1.7, 16.6 ± 1.4; p = .002), respectively. The following variables were significantly higher while running with the stroller after 30 minutes compared to running without it: heart rate (176.3 ± 15.6, 166.1 ± 13.1 b/min; p = .002), lactate concentration (4.9 ± 1.6, 2.8 ± 0.7 mmol; p = .0001), ventilation (104.4 ± 25.6, 90.1 ± 18.0 l/min; p = .006), and RPE (16.6 ± 1.4, 13.8 ± 2.0; p = .001), respectively. CONCLUSIONS: These results indicate that pushing a jogging stroller affects some indices of exercise intensity while running. Gait does not change. These data do not support an association between stroller use during running and an increase risk of orthopedic injury. Further studies should examine these variables at lower intensities that are run by most recreational joggers.

Measurement of Dissolved Oxygen as a Determination of Media Equilibrium During Dissolution Testing

Introduction The scientific community has accepted that dissolved air in dissolution media can affect the dissolution rate of solid dose units. Several methods have been developed to accomplish deaeration, but the industry standard has been the USP method, using heat, vacuum and filtering (1). Alternate methods of deaeration were declared comparable to the USP method by virtue of passing the USP Apparatus Suitability Tests, using USP Prednisone and Salicylic Acid calibrator tablets. Closer examination of this procedure, however, indicated that additional tests of deaeration levels were warranted. The USP Apparatus Suitability Tests, while indicating apparatus suitability, did not measure to any degree the actual amount of dissolved air present. Oxygen, being approximately 20% of air, was easily measured using available dissolved oxygen meters. The measurement of dissolved oxygen allowed a quantitative means to confirm comparability to USPdeaerated media. The use of some deaeration techniques may actually deaerate dissolution media to too low a level. It has been theorized that deaeration to too low a level, such as by vacuum/sonication deaeration, may actually create a disturbance during the dissolution process (2). Dissolved air in dissolution media adjusted to achieve equilibrium. Media with low levels of dissolved air absorbed air until equilibrium was achieved. Conversely, saturated media released dissolved air, until equilibrium was achieved. Since deaeration is basically the removal of dissolved air in the media, it seemed most appropriate to measure a major component of that dissolved air. Dissolved oxygen has long been measured in the waste water treatment industry, and several portable oxygen meters were available, with demonstrated ease of use and reliability in reproducing results. The level of dissolved oxygen, which could be measured, was a direct relation to the amount of dissolved air, or deaeration of the dissolution media. This provided a measurable means of comparing methods of deaeration to the USP method. In addition, the amount of deaeration and time required to achieve the optimal level of deaeration were also determined for each method in use. The objectives of this project were to develop a means of accurately measuring the deaeration of Abstract Scientists have known for years that deaeration of aqueous dissolution media can affect the dissolution rate of solid dosage forms. Several methods have been developed to accomplish deaeration,but the industry standard has been the USP method,using heat,vacuum and filtering. Alternate methods of deaeration may be considered comparable to the USP method by passing the USP Apparatus Suitability Tests,using USP Prednisone and Salicylic Acid calibrator tablets. Closer examination of this procedure,however, indicated that additional tests of deaeration levels were warranted. The USP Apparatus Suitability Tests do not measure to any degree the actual amount of dissolved air present. The use of some techniques may actually deaerate dissolution media to too low a level. Media with low levels of dissolved air absorbed air,and saturated media released dissolved air,until equilibrium was achieved. It was shown that dissolved air in dissolution media adjusted to achieve equilibrium. Acceptable results for the Apparatus Suitability Tests should be combined with measurement of the dissolved oxygen to assure that dissolution testing is conducted on a consistent basis. Through experiments, it was established that a level of dissolved oxygen within a range of 4 – 7 mg/L produced an equilibrium effect in regard to dissolved air in the media,such that no appreciable change occurred during the dissolution process. USP-equivalent media should only be produced by a means that results in near equilibrium of both temperature & dissolved air.

EFFECTIVENESS OF AN ON-ICE VO2 MAXIMUM PROTOCOL FOR FIGURE SKATERS

Slideboard testing has yielded higher VO2 in competitive skaters than a treadmill protocol but an on-ice protocol is more appealing to skaters and their coaches. PURPOSE To evaluate the effectiveness of a short duration, on-ice testing protocol to elicit a VO2 maximum in competitive figure skaters. METHODS To investigate this issue, 14 novice through senior level skaters performed maximal slideboard and on-ice testing protocols using a lightweight, portable oxygen consumption device. Heart rate (HR), volume of oxygen consumption (VO2), minute ventilation (Ve), and RER were assessed for each stage of the slideboard and on-ice testing protocols. There were four stages for both protocols. The slideboard protocol consisted of two minute stages at 50, 60, 70 and 80 slides per minute (spm). The on-ice test consisted of one-minute stages at 70, 80, 90 spm with a final stage of an all-out pace. A one 1-way repeated measure MANOVA assessed differences between each of the stages for both the slideboard and on-ice testing protocols. In addition, repeated measures MANOVA was also used to measure differences in the cardiopulmonary responses between the two protocols. RESULTS The table below summarizes the results. Values are expressed as means and standard deviations.Table: No Caption AvailableCONCLUSION These results indicate that the short-duration, on-ice protocol is effective in eliciting a VO2 maximum in competitive figure skaters.

Using a Reservoir Nasal Cannula in Acute Care

and Oxym i z e r P e n d a n t ( C H A D Therapeutics Inc, C h a t s worth, Calif) brand reservoir cannulas store oxygen in a reservoir during exhalation and deliver a bolus of 100% oxygen upon the next inhalation. These devices were originally designed for portable home oxygen therapy. However, they are finding increasing use in acute care settings for patients who are difficult to supply oxygen via standard nasal cannulas and as high-delivery alternatives to oxygen delivery via a face mask.