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PubMed1977

Subcutaneous emphysema during periodontal surgery: report of a case.

Subcutaneous emphysema (S.E.) of the facial region is an uncommon complication of dental procedures. A case is presented which details the development of S.E. following use of an air-water syringe during periodontal surgery. Differential diagnosis of the condition depends upon accurate historical data and the finding of crepitus on palpation of the involved tissues. Treatment is supportive in nature, although prophylactic antibiotic coverage is suggested. The etiology of S.E. is discussed and judicious use of compressed air or gas-producing medicaments during dental treatment is stressed.

Adult↗
PubMed1991

Pneumoparotis, an unusual occurrence of parotid gland swelling during dental treatment. Report of a case with a review of the literature.

A 24-year-old male with pneumoparotis caused by the use of an air syringe during a routine restorative dental procedure during clinical training is presented. Reflux of air into the parotid gland due to increasing pressure is a rare cause of acute parotid swelling.--A discussion of this unusual case and review of the literature including its differential diagnosis and management form the basis of this report. Judicious use of intra-oral dental instruments using compressed air or gas is advised.

Adult↗
PubMed1986

Generalised use of contrast degradation and contrast improvement factors in diagnostic radiology. Application to vanishing contrast.

Although field area and object thickness are important parameters in comparisons of techniques for optimal reduction of scattered radiation to the image, they are in practice seldom varied. For this reason, we suggest that contrast degradation (CDF) and contrast improvement (CIF) factors be more frequently used and appropriately defined to make the dependence of CDF and CIF on field area (collimation) and object thickness (compression) explicit. Definitions are formulated and the results of experiments and Monte Carlo calculations (comprising effects of collimation, compression, air gap, antiscatter grid, detector thickness) cited to illustrate their usefulness. Currently used expressions for CIF (derived assuming monoenergetic radiation) lack a factor to account for the change in primary contrast caused by the antiscatter method when this affects the energy distribution of the transmitted primary photons (grids and compression) or the fractions of photon energy imparted to the detector (when comparing different detectors). Values of this factor are calculated for some cases. Also, the appropriate choice of physical quantity to be used in the formulae for CDF and CIF is discussed. The energy imparted to the detector is advocated since this is directly related to the detector signals forming the image on, e.g. the x-ray film.

Humans↗
PubMed2003

Benefits of supplemental oxygen in exercise training in nonhypoxemic chronic obstructive pulmonary disease patients.

Supplemental oxygen improves exercise tolerance of normoxemic and hypoxemic chronic obstructive pulmonary disease (COPD) patients. We determined whether nonhypoxemic COPD patients undergoing exercise training while breathing supplemental oxygen achieve higher intensity and therefore improve exercise capacity more than patients breathing air. A double-blinded trial was performed involving 29 nonhypoxemic patients (67 years, exercise SaO2 > 88%) with COPD (FEV1 = 36% predicted). All exercised on cycle ergometers for 45 minutes, 3 times per week for 7 weeks at high-intensity targets. During exercise, they received oxygen (3 L/minute) (n = 14) or compressed air (3 L/minute) (n = 15). Both groups had a higher exercise tolerance after training and when breathing oxygen. However, the oxygen-trained group increased the training work rate more rapidly than the air-trained group. The mean +/- SD work rate during the last week was 62 +/- 19 W (oxygen-trained group) and 52 +/- 22 W (air-trained group) (p < 0.01). After training, endurance in constant work rate tests increased more in the oxygen-trained group (14.5 minutes) than in the air-trained group (10.5 minutes) (p < 0.05). At isotime, the breathing rate decreased four breaths per minute in the oxygen-trained group and one breath per minute in the air-trained group (p = 0.001). We conclude that supplemental oxygen provided during high-intensity training yields higher training intensity and evidence of gains in exercise tolerance in laboratory testing.

Aged↗
PubMed1994

Nebulizer delivery of tobramycin to the lower respiratory tract.

We characterized a tobramycin aerosol generated by five nebulizers: Micron One, Pulmosonic, Pulmo-Aide, DeVilbiss Model 65, and UltraNeb 100 by particle size and drug concentration. The Micron One nebulizer did not produce a recoverable aerosol, while the Pulmosonic had a minimal output; therefore three machines were examined for their ability to deliver tobramycin to the lower respiratory tract of patients with cystic fibrosis (CF). The DeVilbiss 65 had the greatest output: with air as the carrier gas it produced an aerosol with > 60% of the particles having a mean mass aerodynamic diameter (MMAD) of > 5.5 microns. Using helox shifted the MMAD so that > 65% of the particles were < 5.5 microns. Increasing the power in the DeVilbiss 65 increased the output of particles > 9.2 microns, without a change in the particles < 3.3 microns. With air as the carrier gas the Pulmo-Aide and the UltraNeb 100 produced an aerosol with > 60% particles, < 3.3 microns MMAD. Using helox the UltraNeb 100 increased the amount of aerosol with a < 3.3 microns MMAD to 98%. Tobramycin delivery to the lower respiratory tract with the Pulmo-Aide and UltraNeb 100 was compared using air or helox by measuring sputum drug concentration. Pulmo-Aide failed to produce detectable tobramycin in sputum in 2 out of 9 patients with CF. With the UltraNeb 100, all patients had measurable sputum tobramycin immediately after administration (range, 16.2-3385 micrograms/g), but no statistically significant difference was found when using either compressed air, helox, or ambient air.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

SO2-induced enhancement of inhalative allergic sensitization: inhibition by anti-inflammatory treatment.

Epidemiological studies have shown a relationship between air pollution and allergic airway disease. In a previous study we have found that exposure to SO2 enhances allergic sensitization to inhaled ovalbumin (OA) in the guinea pig. We have now investigated the influence of pre-treatment with anti-inflammatory drugs on SO2-induced enhancement of allergic sensitization in this model. Four groups of 6 guinea pigs each were exposed to 5 ppm SO2 on 5 consecutive days over 8 h per day with intermittent inhalation of OA, while the air-control group was exposed to clean air and OA. During the period of SO2 exposure and sensitization three experimental groups were treated with indomethacin (group I), methylprednisolone (group M) and nebulized nedocromil sodium (group N), while the control group remained untreated. Guinea pigs were investigated for sensitization to OA by specific bronchial provocation tests using body plethysmographic measurement of compressed air (CA) and by measurement of specific antibody response in serum. While in the SO2-exposed control group 5 of 6 animals reacted to specific bronchial provocation testing (CA median 0.15 ml, range 0-0.175 ml), only 1 animal was sensitized in group M (CA 0 ml, 0-0.125, p < 0.05), whereas no bronchial reactions were seen in groups I and N (CA 0 ml, 0-0.05, p < 0.025). Specific IgG antibody titres increased in the control group (median 43 EU-->85 EU), but not in the treatment groups (medians group I 35 EU-->35 EU, group M 30-->35 EU, group N 64-->50 EU).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed2003

[Calibration of a room air gas monitor with certified reference gases].

Photo-acoustic infrared spectrometry is considered to be the gold standard for on-line measurement of anesthetic waste gas in room air. For maintenance of the precision of the measurements, the manufacturer recommends calibration of the gas monitor monitor every 3-12 months. We investigated whether the use of reference gases with analysis certificate could serve as a feasible alternative to commercial recalibration. We connected a multi-gas monitor type1302 (Bruel & Kjaer, Naerum, Denmark) to compressed air bottles containing reference gases with analysis certificate. Using a T-piece with a flow-meter, we avoided the entry of room air during the calibration phase. Highly purified nitrogen was used for zero calibration. The reference concentrations for desflurane, enflurane, halothane, isoflurane, and sevoflurane ranged from 41.6-51.1 ml/m(3) (ppm) in synthetic air. Since there is an overlap of the infrared absorption spectra of volatile anesthetics with alcohol used in operating rooms, we performed a cross-compensation with iso-propanol (107.0 ppm). A two-point calibration was performed for N(2)O (96.2 and 979.0 ppm), followed by cross-compensation with CO(2). Nafion tubes were used in order to avoid erroneous measurements due to molecular relaxation phenomena. The deviation of the measurement values ranged initially from 0-2.0% and increased to up to 4.9% after 18 months. For N(2)O, the corresponding values were 4.2% and 2.7%, respectively. Thus, our calibration procedure using certified reference gases yielded precise measurements with low deterioration over 18 months. It seems to be advantageous that the precision can be determined whenever deemed necessary. This allows for an individual decision, when the gas monitor needs to be calibrated again. The costs for reference gases and working time as well as logistic aspects such as storage and expiration dates must be individually balanced against the costs for commercial recalibration.

2-Propanol↗
PubMed1999

The sitting position in neurosurgery: a critical appraisal.

The potential for serious complications after venous air embolism and successful malpractice liability claims are the principle reasons for the dramatic decline in the use of the sitting position in neurosurgical practice. Although there have been several studies substantiating the relative safety compared with the prone or park bench positions, its use will continue to decline as neurosurgeons abandon its application and trainees in neurosurgery are not exposed to its relative merits. How can individual surgeons continue to use this position? Will individual, difficult surgical access cases be denied the obvious technical advantages of the sitting position? Limited use of the sitting position should remain in the neurosurgeon's armamentarium. However, several caveats must be emphasized. Assessment of the relative risk-benefit, based on the individual patient's physical status and surgical implications for the particular intracranial pathology, is of paramount importance. The patient should be informed of the specific risks of venous air embolism, quadriparesis and peripheral nerve palsies. Appropriate charting of patient information provided and special consent issues are essential. An anaesthetic input into the decision to use the sitting position is a sine qua non. The presence of a patient foramen ovale is an absolute contraindication. Preoperative contrast echocardiography should be used as a screening technique to detect the population at risk of paradoxical air embolism caused by the presence of a patent foramen ovale. The technique involves i.v. injection of saline agitated with air and a Valsalva manoeuvre is applied and released. Use of this position necessitates supplementary monitoring to promptly detect and treat venous air embolism. Doppler ultrasonography is the most sensitive of the generally available monitors to detect intracardiac air. The use of a central venous catheter is recommended, with the tip positioned close to the superior vena cava junction with the right atrium, to aspirate intravascular gas. Measures to minimize hypotension associated with the sitting position include a slow, staged positioning over 5-10 min and use of the 'G suit' inflated with compressed air applied to the lower extremities and pelvis. Use of the sitting or upright position for patients undergoing posterior fossa and cervical spine surgery presents unique challenges for the anaesthetist. With appropriate patient selection and preparation, and using prudent intraoperative monitoring and anaesthetic techniques, selected patients should still benefit from the optimum access to mid-line lesions, improved cerebral venous decompression, lower intracranial pressure and enhanced gravity drainage of blood and CSF associated with the sitting position.

Anesthesia↗
PubMed1991

The ideal drug delivery system: a look into the future.

In the very near future, the CFC manufacturers are going to be obliged to stop their production as a result of the "Montreal protocole on substances that deplete the ozone layer". The replacement of these propellants by other fluorinated ones will be possible as soon as their lack of toxicity has been demonstrated. Other substitution substances like haliphatic hydrocarbons (butane, propane) or compressed air generated by the device system itself or the user himself are also under development. The pulverisation can also be obtained by the pressure of a classical propellant onto an aluminum or plastic bag. The dispersion is achieved by means of a regulator which is positioned into the valve. The hand-operated spray pumps with or without compression will also allow the obtention of very small particles though the delivered doses are reduced. However, as few of the new devices have metered valves, they are not yet suitable for pulmonary administration.

Administration, Inhalation↗
PubMed1992

[Dyspnea and ventilatory muscle function during exercise on air and oxygen breathing in patients with chronic obstructive pulmonary disease (COPD)].

Exercise performance and dyspnea in COPD patients have been shown to be improved with supplemental oxygen, although the exact mechanisms resulting in the improvement are still unclear. The purpose of the present study was to investigate a possible relationship between ventilatory muscle function and sensation of dyspnea (modified Borg Scale) during exercise on 20% O2 and 30% O2. Eight patients with COPD (FEV1 1.06 L +/- 0.30 L) exercised on a treadmill two times breathing compressed air or 30% oxygen with a one hour rest in between. The electrical activity of the diaphragm (EMGdi) was recorded with esophageal electrodes, and that of the sternomastoid muscle (EMGsm) was recorded from the fine wire electrodes. The ratio of high frequency (150 to 350 Hz) to low frequency (20 to 47 Hz) power (H/L) of EMGdi was analyzed to assess diaphragmatic fatigue, which was defined as a 20% fall of H/L ratio from the control value. Flow, volume, O2 Saturation (SaO2), esophageal pressure (Pes) and transdiaphragmatic pressure (Pdi) were measured. Tension time index (TTdi) was calculated from Pdi and the ratio of inspiratory time to total time for one cycle (Ti/Ttot). At rest, we measured maximal esophageal pressure (Pesmax), maximal transdiaphragmatic pressure (Pdimax), maximal integrated EMGdi (EMGdimax) and EMGsm (EMGsmmax). Incremental exercise was discontinued by dyspnea. The walking distance achieved was increased in all patients on 30% O2. Dyspnea and desaturation were significantly improved on 30% O2 breathing, and the onset of diaphragmatic fatigue was delayed.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed2000

Clinical and in vitro evaluation of membrane humidifier that does not require addition of water.

It is well known that conventional bubbling humidifiers are capable of producing micro-aerosols contaminated with bacteria. We developed a unique humidifier, named a membrane humidifier, that does not require an external water supply. This new system obtains moisture from room air. We investigated the clinical and in vitro evaluation of the membrane humidifier. Ten patients with chronic pulmonary disease participated in the study. We evaluated the partial pressure of oxygen in arterial blood (PaO2) of 10 patients who used the new device. We conducted an in vitro study to determine whether the device could prevent the bacterial contamination of humidified-oxygen. We passed compressed air contaminated with Pseudomonas aeruginosa outside the hollow fibres of the membrane humidifier, and the humidified-oxygen passed inside the hollow fibres was sampled into nutrient broth periodically for 10 days. We also compared the relative humidity of oxygen humidified by a membrane humidifier with that of oxygen humidified by a bubbling humidifier. There was no significant difference between measured PaO2 while breathing oxygen humidified using a membrane humidifier and that while breathing oxygen humidified using a bubbling humidifier. Cultures of the humidified-oxygen passed through the hollow fibres were negative for bacteria. The membrane humidifier could produce good humidification. The new device appeared to prevent bacterial contamination, and may help to reduce the risk of infection in patients at hospital and home.

Aged↗
PubMed1964

THE ADEQUACY OF THE AIR-MIX CONTROL IN VENTILATORS OPERATED FROM AN OXYGEN SOURCE.

Mean inspired oxygen levels, delivered by the Bennett PR1 and Bird Mark 7 ventilators, were measured at various cycling pressures. Using the Bird ventilator, oxygen levels varied from 51.5 to 96.8%, being highest at low flows and at high cycling pressures. The Bennett PR1 delivers more constant percentages of oxygen, in the range 61.5 to 72.3%. With both makes of machine, each ventilator provides different inspired oxygen levels under comparable circumstances. It is recommended that this type of equipment be driven by compressed air, oxygen being added as required.

Humans↗
PubMed2001

Air-gun pellet injuries to the head and neck in children.

Air-gun pellet injuries to the head and neck are seldom reported in pediatric practice, although they typically occur in children. The adult skeleton stops these projectiles, but they can easily transverse the thin bones of children. If unnoticed, these apparently trivial injuries may have catastrophic consequences. We report three children who sustained a central nervous system injury resulting from a shot by a compressed-air gun. The true nature and extent of the lesion in two infants was established only by neuroradiological investigations. We also briefly review the management and prevention of this type of injury.

Adolescent↗
PubMed1992

[Air embolism].

Air embolism is a dramatic event which threatens the patient's life during invasive therapeutic and diagnostic procedures. Immediately after establishment of the diagnosis treatment in a hyperbaric chamber should be started. The prognosis depends to a certain extent on how quickly the patient is transferred into a hyperbaric chamber. Treatment with hyperbaric oxygen is based on fundamental physical and physiological principles of the action of compressed air and the supply of a large amount of oxygen in a dissolved form into the ischaemic tissue beyond the obstruction. Installation of hyperbaric chambers in hospitals would make successful and prompt treatment of all cases of embolism possible, as well as of some other diseases indicated for hyperbaric oxygen therapy.

Embolism, Air↗
PubMedDate not supplied

A microprocessor temperature-controlled air delivery system for dentinal hypersensitivity testing.

A new microprocessor temperature controlled air delivery system for determining cold and warm temperature thresholds of dentinal hypersensitivity has been designed and built. The temperature range of the unit is -5 degrees to + 85 degrees C. Air is delivered from a typical dental unit air syringe nozzle at a relatively gentle flow rate of 0.2 cu ft/min at operator selected temperatures, with an accuracy of +/- 0.2 degrees C. Within seconds, 1 degree to 5 degrees temperature increments or decrements are accomplished. Larger, i.e., 20 degree increments or decrements, require approximately 15 seconds. The unit can operate from standard 110 V/60 Hz or 230 V/50 Hz outlets and requires a source of compressed air at 60 psig, equivalent to that provided by dental operatory-type air compressors. This report provides a description of the unit, its operation, and data from two clinical studies in which it was used successfully to determine temperature thresholds of dentinal hypersensitivity.

Dentin Sensitivity↗
PubMed2002

Heliox for treatment of exacerbations of chronic obstructive pulmonary disease.

BACKGROUND: Due to its low density properties, helium-oxygen mixtures have the potential to decrease the work of breathing and possibly avoid the need for intubation and mechanical ventilation in patients with respiratory failure. OBJECTIVES: To determine the effect of the addition of helium/oxygen mixtures (heliox) to standard medical care during ventilated and nonventilated acute exacerbations of COPD. SEARCH STRATEGY: Randomized controlled trials were identified from the Cochrane Airways Review Group asthma Register. Primary authors and experts were contacted. References from included and excluded studies, known reviews and texts were also searched. SELECTION CRITERIA: Studies were selected for inclusion if they compared treatment with heliox to placebo (oxygen or air) in randomized controlled trials in adults with an exacerbation of COPD. DATA COLLECTION AND ANALYSIS: Data from all trials were combined using the Review Manager (version 4.1). We planned to perform: 1) random effects weighted mean difference (WMD), with 95% confidence intervals (95% CI), 2) Homogeneity of effect sizes with the Dersimonian and Laird method with p<0.1 as the cut point for significance, and 3) sensitivity analysis on different helium-oxygen mixtures (80/20 vs 70/30), and 4) methodological quality (Jadad score >2 vs. <3). MAIN RESULTS: Four studies, all published between 1997 and 2000 met the inclusion criteria. Two studies compared heliox-oxygen vs. air-oxygen in decompensated COPD patients who were not ventilated. One study was performed in mechanical ventilated patients and one in patients undergoing noninvasive pressure support (NIPSV) ventilated patients. Data could be obtained for only two of the studies. One was a randomized crossover study of 70:30 helium-oxygen vs air-oxygen that involved nineteen patients with acute severe COPD, hospitalized in an intensive care unit for NIPSV. In the patients receiving heliox, arterial PCO2 fell more; WMD 0.8 kPa (95% CI 0.26, -1.34). The second was a randomized trial involved 47 patients with acute COPD, who presented to an Emergency Department randomized to receive updraft nebulization of albuterol and ipratropium bromide using 80% helium and 20% oxygen or compressed air as the driving gas. Treatments were administered at 0, 20, 40, and 120 minutes after randomization. There were no significant differences in the change of FEV1 and FVC between the two groups by either the 1 or 2 hours point. although a small improvement in FEF 25-75 was significantly greater in the heliox group than in the air group. REVIEWER'S CONCLUSIONS: There is currently insufficient evidence to support the use of helium-oxygen mixtures to treat acute exacerbations of COPD in either ventilated or nonventilated patients. Suitably designed randomised controlled trials with the endpoint being the avoidance of mechanical ventilation may be justified.

Helium↗
PubMed1995

Potential dangers of oxygen supplementation during facial surgery.

The use of local anesthesia and intravenous sedation has made same-day outpatient surgery a viable option for many aesthetic and reconstructive procedures. These procedures often include the use of supplemental oxygen. Oxygen-enriched environments increase the combustibility of most materials, and "oxygen pooling" has been suspected to play an integral role in intraoperative fires. A personal experience with an intraoperative explosion and fire during a cosmetic blepharoplasty compelled us to explore the potential danger inherent in the use of supplemental oxygen as well as potential strategies to minimize that danger. This study systematically examines the microenvironment created by the use of oxygen both in the operative field and beneath the surgical drapes under conditions simulating routine facial surgery and various recommended modifications of its delivery. With the use of oxygen supplementation, oxygen concentration beneath the drapes was found to be consistently elevated when compared with ambient air (20.9 percent) and reached levels as high as 53.5 percent. Oxygen concentration in the operative environment was mildly but not significantly elevated. Although criteria for the use of oxygen supplementation are not clear, when administration is deemed necessary, the use of a posterior pharyngeal catheter for its delivery had no advantage over nasal prongs. However, appropriate alternatives include the use of "open face" draping techniques, the use of compressed air beneath the drapes as a substitute for oxygen supplementation in unsedated patients, and cessation of oxygen supplementation for 60 seconds prior to the use of a possible ignition source with oxygen flow rates of less than 3 liters per minute.

Accidents↗
PubMed1999

Influence of self-etching primer drying time on enamel bond strength of resin composites.

OBJECTIVES: In clinical situations, a dentine primer is usually applied to enamel, in addition to dentine. This study was carried out to determine the influence of the air drying time of self-etching primers on their bond strength to enamel. METHODS: Three self-etching primer systems, Fluoro Bond (FB, Shofu Inc.), Liner Bond II (LB, Kuraray Co.) and Mac Bond 2 (MB, Tokuyama Co.) were employed. Bovine mandibular incisors were mounted in self-curing resin and the enamel surfaces were wet ground with number 600 SiC paper. Following primer application, the enamel surface was dried with compressed air for 0, 2, 5, 10, 20, and 30 s from 10 cm above the enamel surface using a three-way syringe. Adhesives were applied and composites were condensed into a Teflon mold (4 x 2 mm) placed on the enamel and light activated. Ten samples per test group were stored in 37 degrees C water for 24 h, then shear tested at a crosshead speed of 1.0 mm min-1. One-way ANOVAs followed by Duncan tests (p < 0.05) were done. RESULTS: The enamel bond strengths varied with the different air drying times and ranged from 8.2 +/- 3.2-17.4 +/- 3.0 MPa for LB, 10.9 +/- 2.8-16.3 +/- 3.3 MPa for FB, and 17.5 +/- 2.5-19.4 +/- 2.2 MPa for MB. For LB and FB, there appeared to be a minimum drying time of 10 s. LB was the most affected by drying time, while MB did not change. CONCLUSIONS: The data suggests that the enamel bond strengths of these bonding systems can be influenced by the drying time of the primer applied prior to bond agent application and the tendency was different among the systems studied.

Acid Etching, Dental↗