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At least 559 records · Page 31Linked to original sources
PubMed1992

Ambient pressure air/oxygen blender.

This article presents a unique air/oxygen mixing device specifically designed for respiratory therapy applications where compressed air is not available. The need for such a device has increased drastically over recent years because of the increasing number of ventilator-dependent patients being cared for in private homes, which often lack facilities such as pressurized air. This pneumatically driven blender utilizes a specialized poppet-seat configuration that proportionally adjusts the gas flow area, in response to the ventilator demand, without altering the set air and oxygen percentage mixtures. A prototype of the device was designed and constructed. Tests producing favourable blending accuracy and pressure drop results are presented.

Air↗
PubMed1995

35% CO2 challenge in panic and mood disorders.

20 patients with Panic Disorder (PD), 19 patients with Mood Disorder (MD) and 20 healthy controls inhaled one vital capacity of 35% CO2-65% O2 gas mixture and of compressed air in a double-blind, random, cross-over design. Only PD patients showed a strong reaction to 35% CO2 while MD patients and controls did not react significantly. These results support the specificity of the 35% CO2 challenge in PD patients and suggest that PD and MD are separate disorders.

Adult↗
PubMed1990

Specific sensitivity of patients with panic attacks to carbon dioxide inhalation.

One inhalation of 35% CO2 in oxygen was administered to 36 patients with anxiety disorders and 14 healthy controls. Eighteen patients had a diagnosis of panic disorder (PD) and 18 of obsessive-compulsive disorder (OCD). As a placebo control for CO2, compressed air was administered in a double-blind design. Immediately before and after the inhalation, levels of anxiety and DSM-III-R symptoms of panic were assessed. CO2 elicited high levels of subjective anxiety in the PD group. Patients with OCD were hardly affected by the inhalation, and did not differ from healthy controls. These results suggest that CO2 challenge should be considered as a specific probe for subjects with panic-anxiety. It is speculated that CO2 may trigger some as yet undefined mechanisms, possibly linked to ventilation control, which demarcate panic from other types of pathological anxiety.

Administration, Inhalation↗
PubMed1994

Assessment of spinal cord trauma using evoked potentials in a rat model of decompression sickness.

A rapid quantitative technique for assessing spinal cord trauma in a rat model of decompression sickness is described. Evoked potentials are measured from the lower limbs of rats before and after dives with compressed air in a hyperbaric chamber. Under chloral hydrate anesthesia, the sciatic nerve is stimulated at the sciatic notch with needle electrodes and platinum/iridium electrodes are used to record the action potentials from the plantar muscles. Analysis showed that the sensory reflex response was markedly depressed in the rats soon after diving and did not recover for up to 5 days. The motor response was similarly affected although to a lesser degree. The latency of the reflex response also became prolonged after 3 days. The significant and complex pattern of neurological dysfunction shown by this electrophysiologic technique validates the use of the rat model for the study of spinal cord decompression sickness. This technique should aid studies aimed at testing new therapies for this disease.

Action Potentials↗
PubMedDate not supplied

Psychopathological profile of 35% CO2 challenge test-induced panic attacks: a comparison with spontaneous panic attacks.

Our aim was to describe the clinical features of 35% CO2-induced panic attacks in patients with panic disorder (PD) (Diagnostic and Statistical Manual and Mental Disorders, Fourth Edition) and compare them with the last spontaneous panic attack in patients with PD who had not had a panic attack after the 35% CO2 challenge test. We examined 91 patients with PD submitted to the CO2 challenge test. The test consisted of exhaling as fully as possible, took a fast vital capacity breath, held their breath for 8 seconds, exhaled, and then repeated the fast vital capacity breath, again holding for 8 seconds. The patients inhaled the 35% CO2/65% O2 mixture or atmospheric compressed air, randomly selected in a double-blind design. Scales were applied before and after the test. A total of 68.1% (n = 62) patients with PD had a panic attack (responders) after the CO2 test (chi2(1) = 25.87, P = .031). The last spontaneous panic attack and the symptom profile from the patients with PD who had not had a panic attack after the test (n = 29, 31.9%) were described to compare. The responders had more respiratory symptoms (chi2(1) = 19.21, P < .001), fulfilling the criteria for respiratory PD subtype (80.6%); the disorder started earlier (Mann-Whitney, P < .001), had a higher familial prevalence of PD (chi2(1) = 20.45, P = .028), and had more previous depressive episodes (chi2(1) = 27.98, P < .001). Our data suggest that there is an association between respiratory PD subtype and hyperreactivity to a CO2 respiratory challenge test. The responders may be a subgroup of respiratory PD subtype with future diagnostic and therapeutic implications.

Adult↗
PubMed2006

Power-assisted liposuction.

This article describes vibroliposuction, a mechanical technique using compressed air to perform liposculpture.

Adult↗
PubMed2005

Effect of milling and sieving on functionality of dry powder inhalation products.

Alpha-lactose monohydrate is the standard excipient used as diluent or carrier in dry powder inhaler (DPI) formulations. Earlier studies have already revealed that raw materials for the production of inhalation grade lactose have to be carefully selected in order to avoid batch-to-batch variability. In the present study, the effect of milling and milling intensity on the flow properties and the physico-chemical characteristics of lactose crystals has been determined. The milled lactoses were then further processed by sieving to give lactose qualities with identical size distribution data, but different batch history (non-milled and milled at different conditions). These were then used to manufacture low concentration (0.25%) drug blends with the model drugs salbutamol sulphate (SBS) and beclometasonedipropionate (BDP); the blends were analysed with a Multistage Liquid Impinger (MLI) after delivery from an Easyhaler and an Aerolizer device. It could be shown that gentle milling already results in surface defects on the lactose crystal which are further enhanced by using a higher milling intensity. Produced fine lactose particles during the milling process strongly adhere to the lactose surface and cannot be removed by compressed air which is used for the particle sizing. By trend, a higher milling intensity resulted in higher fine particle fractions (FPF) with both devices. Also, SBS was found to generally give higher fine particle fractions than BDP, independent from the device used. In conclusion, lactose pre-treatment by gentle or strong milling affects the carrier surface and thereby the aerosolization properties of drug/lactose blends produced.

Aerosols↗
PubMed2006

Comparison between effectiveness of a low-viscosity glass ionomer and a resin-based glutaraldehyde containing primer in treating dentine hypersensitivity--a 25.2-month evaluation.

OBJECTIVES: The null-hypothesis tested was; there is no difference in effectiveness between a new low-viscosity glass ionomer and a resin-based glutaraldehyde containing primer in treating hypersensitive teeth after 2 years. METHODS: Using a split-mouth design, hypersensitive teeth in 14 adult patients were randomly assigned to 2 treatment groups. Hypersensitive tooth surfaces were covered with a low-viscosity glass ionomer (Fuji VII) and a resin-based glutaraldehyde containing primer (Gluma Desensitizer). The discomfort interval scale (DIS) ranging from 0 to 4 was used to test the level of hypersensitivity before and after treatment, and at 3 months using compressed air blown for 2 s, and at 1 and 25.2 months using a telephone interview. Differences between and within the treatment groups were tested using the sign rank test. RESULTS: Evaluations in the gluma group were discontinued after 3 months. The mean DIS score for hypersensitive teeth in the glass ionomer group was statistically significantly lower than that in the gluma group, immediately after application (p=0.0005), after 1 month (p=0.02) and after 3 months (p=0.003). After 3 months, 11/14 of the hypersensitive teeth in the glass ionomer group and 2/14 in the gluma group were free of sensitivity. The mean DIS score for hypersensitive teeth in the glass ionomer group remained low after 19.2 months (0.25: S.E.=0.13) and 25.2 months (0.22: S.E.=0.15). CONCLUSIONS: The null-hypothesis was rejected. The low-viscosity glass ionomer (Fuji VII) is more effective in treating hypersensitive teeth than Gluma Desensitizer after 3 months. The positive treatment effect of the glass ionomer continued until 25.2 months.

Adult↗
PubMed2006

Prolonged mild hypoxia alters fetal sheep electrocorticogram activity.

OBJECTIVE: To assess the effects of prolonged mild hypoxemia on fetal brain electrocorticogram (ECoG) in late gestation. STUDY DESIGN: Fetal and maternal catheters were placed under general anesthesia and animals allocated at random to receive intratracheal maternal administration of either nitrogen (n = 8) or compressed air (n = 8). Five days after surgery (125 days' gestational age), nitrogen infusion was adjusted to reduce fetal brachial artery PO2 by 25%. The targeted decrease in fetal oxygenation was maintained for 5 days while fetal ECoG activity and fetal and maternal cardiovascular variables were continuously recorded. Data are presented as mean +/- SEM and were analyzed by two-way analysis of variance (ANOVA) or two-sample t test. RESULTS: Nitrogen infusion decreased fetal Po2 by 26% (20.5 +/- 1.7 versus 14.3 +/- 0.8) without changing fetal PCO2 or pH. Mild fetal hypoxemia was associated with fetal tachycardia and increased fetal blood pressure (P < .05). Fetal ECoG in hypoxic fetuses showed a significant decrease in the time spent in high voltage (HV) (P < .05) and an increase in the time spent in low voltage (LV) and in the number of low voltage events (P < .05). Also, a significant decrease in the proportion of 1-4 Hz and an increase in the proportion of 13-20 Hz frequencies was observed in LV events without a significant change in the frequency profile of HV events (P < .05). CONCLUSION: Prolonged mild hypoxemia significantly altered fetal homeostasis as reflected by the sustained tachycardia and increased blood pressure. Fetal ECoG activity was affected significantly in a qualitatively and quantitative manner by mild prolonged hypoxemia.

Animals↗
PubMed2006

Rapid and sensitive FAME analysis of bacteria by cold trap injection gas chromatography.

Whole cell fatty acid analysis is commonly used to identify bacteria. A cold trap, using a commercially available device that directs a stream of compressed air across a section of the GC column, is used to focus peaks at the head of the column. When combined with a rapid sample processing method that uses smaller volumes of solvents, it becomes possible to correctly identify bacteria from 1 to 2 mg of biomass.

Bacteria↗
PubMed2006

A portable and low-cost fMRI compatible pneumatic system for the investigation of the somatosensensory system in clinical and research environments.

There still is a need for devices that allow reproducible stimulation of skin areas of the human body. We constructed a stimulation system and tested it by using brief pneumatic stimulation to the right thumb of nine healthy volunteers. BOLD-signals in response to tactile stimulation with frequencies of 1, 3 and 5 Hz were measured using a 3T MRI scanner. The stimulation device consists of synthetic membranes connected to plastic tubes capable of carrying compressed air, and an electronic component, which controls the on- and off-switching of an electromagnetic valve. The valve near the MR-scanner did not lower the image quality. Primary somatosensory activation contralateral to the stimulation site was reliably detected in response to a stimulus magnitude of 3.5 bar in all volunteers. 1 Hz stimulation resulted in higher maximal percentage BOLD-signal changes. Our device is an easy-to-construct, low-cost and portable tool suitable for research and clinical environments. It permits passive non-painful stimulation relevant for clinical assessments and is also compatible with magnetoencephalography (MEG) and electroencephalography (EEG). In basic and clinical research, this device therefore contributes to meaningful comparisons between results obtained with different techniques.

Adult↗
PubMed2005

[Early detection of asymptomatic dysbaric osteonecrosis of the shoulder after type 1 decompression sickness: a case report].

INTRODUCTION: Dysbaric osteonecrosis is a rare illness in professional divers and compressed-air workers. The correlation between dysbaric osteonecrosis and previous decompression sickness with osteoarthromuscular pain (type 1 decompression sickness) remains a controversial subject. The probability for ischemic lesions detected with MRI to turn into osteonecrosis after decompression sickness is still not established. EXEGESIS: The authors report the case of a military diver declared definitely medically unfit to dive after the occurrence of advanced dysbaric osteonecrosis of the shoulder, eight months after decompression sickness treated with hyperbaric oxygen, in the same area. A close link between those two events and the requirement for monitoring the follow-up of acute type 1 decompression sickness are discussed. CONCLUSION: Every decompression sickness with osteoarthromuscular pain should be early examined with MRI in order to screen osteomedullar damages liable to worse with diving and change subsequently in bone necrosis.

Adult↗
PubMed2004

Supplemental oxygen increases arterial stiffness in chronic obstructive pulmonary disease.

STUDY OBJECTIVES: Recently, we demonstrated significantly improved baroreflex sensitivity (BRS) and autonomic balance after 31% supplemental oxygen (SuppO2) in resting patients with chronic obstructive pulmonary disease (COPD). In order to investigate whether peripheral arterial stiffness changes may play a role, we evaluated changes in peripheral arterial stiffness and BRS after SuppO2. DESIGN: Single blinded crossover design. SETTING: Pulmonary exercise testing laboratory. PARTICIPANTS: Seventy subjects with moderate to severe COPD. INTERVENTIONS: We measured arterial vascular stiffness using the augmentation index via contour analysis of the radial pulse obtained from applanation tonometry. BRS was derived using the sequence method before and after treatments with compressed air (CA) and 30% SuppO2 in 70 individuals with COPD via a counterbalanced crossover design. RESULTS: Paired t-tests indicated significant differences in oxygen saturation (SaO2) following SuppO2 when compared to CA (mean 96.0+/-2.0% SuppO2 versus mean 92.6+/-3.6% CA, P<0.001). BRS was significantly greater following SuppO2 compared to CA (mean 3.5+/-2.3 ms/mmHg SuppO2 versus mean 3.1+/-2.1 CA ms/mmHg, P<0.03). Vascular stiffness was significantly increased with SuppO2 when compared with CA (mean 13.3+/-6.1% SuppO2 versus mean 10.8+/-4.9% CA, P<0.001). CONCLUSIONS: Our findings indicate that oxygen supplementation ameliorates BRS by changes in vasomotor activity. The amelioration of the BRS into a more normal range is a move towards the restoration of more normal physiology.

Aged↗
PubMed2004

Removal of soft deposits from the distribution system improves the drinking water quality.

Deterioration in drinking water quality in distribution networks represents a problem in drinking water distribution. These can be an increase in microbial numbers, an elevated concentration of iron or increased turbidity, all of which affect taste, odor and color in the drinking water. We studied if pipe cleaning would improve the drinking water quality in pipelines. Cleaning was arranged by flushing the pipes with compressed air and water. The numbers of bacteria and the concentrations of iron and turbidity in drinking water were highest at 9 p.m., when the water consumption was highest. Soft deposits inside the pipeline were occasionally released to bulk water, increasing the concentrations of iron, bacteria, microbially available organic carbon and phosphorus in drinking water. The cleaning of the pipeline decreased the diurnal variation in drinking water quality. With respect to iron, only short-term positive effects were obtained. However, removing of the nutrient-rich soft deposits did decrease the microbial growth in the distribution system during summer when there were favorable warm temperatures for microbial growth. No Norwalk-like viruses or coliform bacteria were detected in the soft deposits, in contrast to the high numbers of heterotrophic bacteria.

Bacteria↗
PubMed1999

Intra-abdominal pressure mechanism for stabilizing the lumbar spine.

Currently, intra-abdominal pressure (IAP) is thought to provide stability to the lumbar spine but the exact principles have yet to be specified. A simplified physical model was constructed and theoretical calculations performed to illustrate a possible intra-abdominal pressure mechanism for stabilizing the spine. The model consisted of an inverted pendulum with linear springs representing abdominal and erector spinae muscle groups. The IAP force was simulated with a pneumatic piston activated with compressed air. The critical load of the model was calculated theoretically based on the minimum potential energy principle and obtained experimentally by increasing weight on the model until the point of buckling. Two distinct mechanisms were simulated separately and in combination. One was antagonistic flexor extensor muscle coactivation and the second was abdominal muscle activation along with generation of IAP. Both mechanisms were effective in stabilizing the model of a lumbar spine. The critical load and therefore the stability of the spine model increased with either increased antagonistic muscle coactivation forces or increased IAP along with increased abdominal spring force. Both mechanisms were also effective in providing mechanical stability to the spine model when activated simultaneously. Theoretical calculation of the critical load agreed very well with experimental results (95.5% average error). The IAP mechanism for stabilizing the lumbar spine appears preferable in tasks that demand trunk extensor moment such as lifting or jumping. This mechanism can increase spine stability without the additional coactivation of erector spinae muscles.

Abdomen↗
PubMed2003

Socket with built-in valves for the interconnection of microfluidic chips to macro constituents.

This paper reports a prototype for a standard connector between a microfluidic chip and the macro world. This prototype demonstrate a fully functioning socket for a microchip to access the outside world by means of fluids, data signals and energy supply. It supports up to 10 channels for the input and output of liquids or gases, as well as compressed air or vacuum lines for pneumatic power lines. The socket has built-in valves for each flow channel. It also contains 28 pins for the connection of electrical signals and power. Built-in valves make it possible to control the flow in each channel independently. A chip ( 11.0 x 11.0 x 0.9 mm) can be mounted into or dismounted from the socket with one touch. The fluidic connectors of the socket are designed to contact vertically on the top of chip. And the electrical connectors (the spring array) of that physically support the chip and contact lead pads at the bottom of chip. No adhesives or solders are used at any contact points. The pressure limit for the connection of working fluids was 0.2 MPa and the current limit for the electrical connections was 1 A. This socket supports both serial and parallel processing applications. It exhibits great potential for developing microfluidic systems efficiently.

Equipment Design↗
PubMed1993

The Swiss Lithoclast: a new device for endoscopic stone disintegration.

Even in the presence of extracorporeal shock wave lithotripsy there is still the need for endourological treatment of stones in the urinary tract. Stone fragmentation usually is achieved with either ultrasonic, electrohydraulic or laser lithotripsy. We report our early experience with a new, simply constructed machine at a reasonable cost for endoscopic stone disintegration--the Swiss Lithoclast. The principle of this lithotriptor is based on pneumatic shock waves induced by the central compressed air system of a hospital or by a compressor. This device was used to treat 151 patients with stones in the kidney, ureter, bladder or a Kock pouch continent urinary diversion. Endoscopic fragmentation was successful in all patients. Independent of the composition, all stones were disintegrated within a short period, indicating that the device may well represent an attractive alternative to standard endoscopic lithotriptors.

Adolescent↗
PubMed1992

The Swiss Lithoclast: a new device for intracorporeal lithotripsy.

Modalities available for performing intracorporeal lithotripsy include ultrasonic, electrohydraulic and laser procedures. We present our experience with a new and unique technology for performing intracorporeal lithotripsy, namely the Swiss Lithoclast. This simple and inexpensive device uses compressed air to activate a solid probe in a manner similar to that of a jackhammer. We report the use of the Lithoclast in 31 cases, consisting of 6 renal calculi approached percutaneously, 17 ureteral calculi and 8 bladder calculi. The Lithoclast successfully fragmented 94% of the calculi. There were no intraoperative or long-term complications directly related to the use of this device. We have found the Swiss Lithoclast to be a safe, effective and inexpensive means of performing intracorporeal lithotripsy for calculi located throughout the urinary tract.

Adult↗