Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Compressed Air”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17Linked to original sources
PubMed1990

Decompression sickness in the Singapore Mass Rapid Transit Project.

In the Singapore Mass Rapid Transit Project (MRT), 11 km of underground tunnels were built using compressed air. 1,737 compressed air workers (CAWs) were employed in the project. They underwent 188,538 man decompressions at the various compressed air worksites. 160 CAWs developed Type I decompression sickness (DCS) and 4 developed Type II DCS. This gave an overall incidence of 0.087%. The adoption of strict medical selection, strict adherence to decompression procedures and the provision for acclimatization of newstarters contributed greatly to this low incidence. Prompt treatment of DCS accounted for the low relapse rate. The clinical presentation of DCS is discussed here. Prevention of DCS by worksite environmental and work-practice monitoring are advocated.

Decompression Sickness↗
PubMed1983

Critical review of international standards for respiratory protective equipment - III. Practical performance tests.

This paper, the third in a series of papers devoted to review of international standards for Respiratory Protective Equipment (R.P.E.), summarizes in tabular form, compares, and critically reviews standards of different countries or organizations pertaining to practical performance tests (Man Tests). There are similarities, differences and omissions in the national standards that deserve attention. Of the countries or organizations that require Man Tests on particulate and/or gas and vapor respirators, none described in detail the tests to be performed. For example, CEN requires that Man Tests be conducted on gas/vapor respirators under realistic conditions to determine imperfections that cannot otherwise be determined by other performance tests, but does not stipulate the testing procedure. With respect to fresh-air hose, compressed-air line and self-contained breathing apparatus R.P.E., only Great Britain and CEN present specific Man-testing requirements in detail. Man Tests for all types of R.P.E. have a specific purpose: to determine any imperfections in, or malfunction of the apparatus under simulated work conditions. One major difference, however, is in the kind of work simulation activities required. In the testing of fresh-air hose and compressed-air line respirators, for instance, CEN describes in great detail, a variety of activities to be conducted. Great Britain merely states that the subjects shall work in practical conditions. Another important disparity relates to the conditions under which the test is to be performed. For example, CEN requires a heavy-duty test and a cooled chamber test, as well as tests under normal and low temperature conditions. Great Britain, on the other hand, requires only the latter two tests. Still other differences lie in the kinds of medical surveillance required during testing and the evaluation criteria used for assessment.

Air Pollutants, Occupational↗
PubMed1978

[Effect of the propellants O2 and CO2 on the efficacy of oral irrigation].

The therapeutical results obtained with oral irrigations when O2 or CO2 was used as a propellant air compared with those achieved with compressed air. The assessment of the therapeutical success was based on the periodontal disease index according to Kötzschke and the exsudate heights according to Egelberg. A significant improvement in the periodontal condition was stated in all three groups of patients. Though only the exsudate values for the O2 group were significantly better than those for the compressed air group, being the only difference between the groups which was significant, the greater efficiency of the O2 and CO2 application (compared to compressed air application) is, nevertheless, obvious and interpretable. The therapeutical results obtained permit the statement that a technically perfect device and the further increase of the partial pressure of O2 or CO2 in the irrigation fluid will lead to even better therapeutical results, for which purpose the suggestions given should be considered in establishing the indication. The favourable results achieved with compressed air testify to the beneficial action of each irrigation or spray treatment.

Aerosols↗
PubMed2006

Development of the transtibial prosthesis controlled pneumatically and electrically by microcomputer system.

This report represents the development of the prototype transtibial prosthesis to assist a smooth and comfortable walking for an unilateral amputee. This prosthesis is composed of two air cylinders, solenoid valves, portable and small air tank for compressed air storage, a multiple sensor system and a microprocessor. Two air cylinders are located around the rods to act as antagonistic and agonistic muscles. The system causes flexion and extension of the foot plate jointed at the ankle with compressed air, injected -or discharged via a solenoid or electromagnetic valves. The valves or solenoids are controlled with a microprocessor (Microchip Technology Inc., PIC16F876), the microprocessor generates control signals to the interface circuits for valve opening and closing consistent with the foot position during the walking phase. The control patterns generated in the microprocessor are modified with feedback from the touch sensor, ankle joint angle sensor and the two dimensional acceleration sensor. The primary walking pattern for an individual amputee should be developed through the gait analysis with video.

Amputation, Surgical↗
PubMed1989

[Exercise induced hypoxemia and exercise tolerance in patients with COPD and the benefits of oxygen supplementation].

In order to evaluate the benefits of O2 supplementation during exercise, slowly incremental treadmill exercise tests were performed twice with 30 minutes interval rest in fourteen patients with severe COPD. The patients breathed room air. 31/min of compressed air by nasal prongs, and 31/min of supplemental oxygen in single blind fashion at random. The patients who developed arterial desaturation below 88% on exercise, group D, showed slight but significant increase in walked distance (397 m vs 424 m) and significant decrease in breathlessness (22.9 vs 16.9) on oxygen as compared to on air. On the other hand in patients without significant arterial desaturation, group S, there was no improvement in those parameters. The increase in walked distance on oxygen was closely related with the decrease in mean inspiratory flow (VT/Ti), blood lactate level, and CO2 production at identical work load. Plasma human atrial natriuretic peptide (h-ANP) levels in group D increased with exercise from a resting value of 27.6 +/- 6.9 to 44.0 +/- 9.0 on compressed air whereas the increase was significantly suppressed to 35.4 +/- 9.0 on oxygen. In group S there was no difference in the increase of plasma h-ANP levels between air and oxygen breathing during exercise (33.1 +/- 5.1 vs 31.9 +/- 9.6). A close correlation (r = 0.908) was found between mean pulmonary artery pressures and plasma h-ANP levels at rest and during exercise performed in four patients breathing air and oxygen. Those findings suggested that arterial plasma h-ANP levels reflected the right ventricular afterload and that they could be used to evaluate the effectiveness of O2-supplementation during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed2001

Characterization of vehicular brake service personnel exposure to airborne asbestos and particulate.

Evaluation of fibers and total particulate generated during the servicing of drum brakes on motor vehicles as well as during the resurfacing (arcing) of brake shoes was conducted. Conditions for the studies were based on review of contemporary (approximately 1950-1980) working practices in the industry. This work was conducted in two parts. Phase 1 estimated the release of asbestos fibers and total particulate during brake inspection and replacement of light-duty vehicle rear drum brakes at an auto/truck repair facility. Two distinct work practices were evaluated: One rear wheel from each vehicle was serviced using compressed air to remove dust while the second rear wheel was serviced without compressed air. Area and personal monitoring of fiber levels demonstrated counts (without compressed air) that ranged from 0.05 to 0.2 f/cc. Fiber counts when using compressed air averaged from 0.05 to 0.9 f/cc. Results from real-time aerosol monitoring indicated elevated dust levels for about 15 minutes after blow out. With shop doors open, dust levels increased to 5.0 mg/m3 at blow out and returned to 0.08 mg/m3 within two minutes. When the shop doors were closed, the dust levels reached 13.5 mg/m3 at blow out and decreased to 1.68 mg/m3 within one minute and to background within 14 minutes. The Phase 2 series evaluated the release of fibers and other particulate from are grinding. For operations conducted under conditions simulating a workplace, a mean of 0.19 f/cc +/- 0.16 was determined. Dust levels averaged 0.25 mg/m3 +/- 0.05. Brake service monitoring in these tests demonstrates that asbestos fiber concentrations, considered on a time weighted average basis, should not exceed currently acceptable workplace standards whether or not the worker uses compressed air, nor during the arc grinding process when arcing is conducted in accord with the design of the equipment.

Air Pollutants, Occupational↗
PubMedDate not supplied

Effect of application technique and dentin bonding agent interaction on shear bond strength.

This study evaluated the interaction of five clinical application techniques and the shear bond strength of four DBAs (OptiBond FL, Clearfil SE Bond, PQ1 and Prime & Bond NT). A hybrid resin composite (Herculite XRV restorative resin) was attached to human dentin surfaces using five application techniques: Group A--adhesive spread with a 3M brush for 30 seconds, followed by compressed air 0.5 cm from the surface for one second to remove the excess adhesive. Group B--adhesive spread with a 3M brush for 30 seconds, followed by compressed air 0.5 cm from the surface for three seconds to remove the excess adhesive. Group C--adhesive spread with 3M brush for 30 seconds, excess adhesive removed with a clean brush, two strokes side by side, no compressed air. Group D--adhesive spread with a Micro-applicator brush for 30 seconds followed by compressed air 0.5 cm from the surface for one second to remove the excess adhesive. Group E--adhesive spread with a Micro-applicator brush for 30 seconds, the excess adhesive removed with a clean brush, two strokes side by side and no compressed air. The specimens were stored in distilled water at 37 degrees C for 24 hours, followed by thermocycling between 5 degrees C and 55 degrees C for 1,000 cycles. The shear bond strengths were determined on a universal testing machine operating with a crosshead speed of 5 mm/minute. The fracture sites were examined by 20x stereo microscope to determine the type of failure that occurred during the debonding procedure. Bond strength data were compared with analysis of variance at a significance level of p<0.05. Post hoc comparisons of means were performed with t-tests with p-values adjusted for multiple comparisons. This in vitro study concluded that there was an interaction between the application technique and bonding agent tested. All DBAs utilized the one-second compressed air technique, which yielded the highest bond strengths.

Air↗
PubMed1989

Dysbaric disorders: aseptic bone necrosis in tunnel workers and divers.

Dysbaric osteonecrosis is a serious complication for those exposed to a hyperbaric environment, with prevalence of 17% amongst compressed air workers and 4.2% amongst divers. Bone lesions are characteristically multiple and bilateral, occurring frequently in the shafts of the femora or tibiae and the heads of the humeri or femora. A proportion of the lesions will lie next to the joint surface, the so called juxta-articular lesion, and these may progress to a structural failure and secondary osteoarthritis. These lesions can be severely disabling, especially in a young adult male. When related to the occupational history the prevalence of bone lesions, both in compressed air workers and divers, increases with age, experience and with greater pressures of air or at greater depths. Moreover, acute attacks of decompression sickness, the bends, are more liable to be associated with subsequent bone lesions. Current decompression schedules certainly reduce the bends rate but, no matter how strictly adhered to, will not prevent the development of dysbaric osteonecrosis. It is possible that bone necrosis could result solely from exposure to a high pressure of air, either from work in compressed air or diving. Those men with positive bone lesions should be advised to seek expert medical opinion and probably advised to discontinue work in compressed air or diving if a juxta-articular lesion is present. Detection of bone necrosis depends on good quality radiographs with reliable interpretation, preferably by double observation, especially in the early stages. Lesions, especially when early or doubtful, can be confirmed by CT or bone scintigraphy. MRI promises to detect osteonecrosis in the very early stages but is not yet readily available. To detect dysbaric osteonecrosis at an early stage it is important to monitor both compressed air workers and divers with regular radiological skeletal surveys or bone scintigraphy. In 1987, the Bone Necrosis Working Group of the Decompression Sickness Panel recommended that all divers should have a radiological survey on completion of their initial diving training and that bone scintigraphy should be used for subsequent surveillance for certain groups, including those diving deeper than 30 metres, where the time at depth exceeds 4 hours, when experimental decompression is used and in other situations.

Atmospheric Pressure↗
PubMed1988

Air or oxygen as driving gas for nebulised salbutamol.

The effects of nebulised salbutamol driven by compressed air or oxygen were compared in a randomised crossover study during 27 attacks of acute asthma. Arterial oxygen saturation fell by 2-6% during or after treatment in 10 cases: seven with compressed air, two with oxygen, and one with both driving gases. Hypoxaemia occurred in younger children and in those who fell asleep, but was not related to the level of arterial oxygen saturation before treatment or the size of the response to bronchodilator therapy. More children fell asleep with compressed air nebulisation. Arterial oxygen saturation improved and heart rates remained stable during treatment when oxygen was the driving gas. After treatment, however, arterial oxygen saturation fell and heart rates rose to values that were similar to those after treatment with compressed air. The falls in arterial oxygen saturation we observed, though comparatively small, would be clinically important on the steep part of the oxygen dissociation curve, and our results emphasise that families with home nebulisers should seek medical advice early when their children develop severe asthma. The benefits of using oxygen as the driving gas during nebulisation were transient, and in severe asthma treatment with oxygen needs to be continued after the nebulised salbutamol has been given.

Acute Disease↗
PubMed2003

[Subcutaneous emphysema of hand and forearm due to high-pressure injection of air].

Cutaneous injuries with crepitus suggest infections caused by gas forming organisms. The non infectious causes of subcutaneous emphysema are under recognized, and are usually of good prognosis. A 27 year old man presented a swollen hand and forearm. He had suffered a small puncture wound in a finger. He had cleaned and dried the area briefly with compressed air, developing a fast swelling of this hand and forearm. At examination, we found extended subcutaneous emphysema in a radiography and observed subcutaneous air in the hand and forearm; 48 hs later there was no evidence of subcutaneous air. The presence of subcutaneous emphysema is always worrisome and such cases must be considered in the differential diagnosis. The exposition of preexistent wounds to compressed air sources (high pressure pneumatic tools, scuba compressed air tubes, compressed air guns) identifies the cause and prevents unnecessary surgical interventions.

Adult↗
PubMed1996

Oxygen administration enhances memory formation in healthy young adults.

Despite numerous studies indicating that transient cerebral oxygen depletion has a detrimental effect on cognition, surprisingly little research has examined the possibility of cognitive enhancement following elevated oxygen levels in healthy adults. Here, we present evidence demonstrating that oxygen administration improves memory formation. Inhalation of oxygen immediately prior to learning a word list resulted in a significant increase in mean number of words recalled 10 min later, compared to subjects who inhaled oxygen immediately prior to recall or to controls who underwent no intervention. In a second experiment, the learning-test interval was increased to 24 h and, again, only pre-learning (but not pre-test) oxygen administration resulted in significant memory facilitation. In experiment 3, inhalation of oxygen prior to learning was compared to inhalation of compressed air, oxygen (but not compressed air) resulted in a significant increase in word recall 24 h later. In no experiment did oxygen have a significant effect on any mood item measured. We interpret these data as indicating that increased availability of cerebral oxygen facilitates cognition, including memory consolidation. The implications for the psychopharmacology of cognitive enhancement are considered in the context of cholinergic systems and neural metabolism.

Adult↗
PubMed1978

Oxygen-assisted exercise in chronic obstructive lung disease. The effect on exercise capacity and arterial blood gas tensions.

Twenty-six patients with severe chronic obstructive lung disease exercised on a treadmill while breathing either room air, supplementary compressed air, or O2. Endurance was significantly increased by O2, but there was no improvement in maximal work rate. No relation was found between increased endurance and the degree of hypoxia, hypercarbia, or acidosis during exercise or the changes in these while breathing O2.

Acidosis, Respiratory↗
PubMed1979

Increased blood-brain barrier permeability to tetracycline in rabbits under dysbaric conditions.

Alteration of the blood-brain barrier (BBB) by dysbaric exposure may have relevance in several areas of hyperbaric medicine. Drugs administered to persons exposed to dysbaric conditions, e.g., divers, compressed air workers, may penetrate the brain in amounts that could produce toxic or undesirable effects. Modification of the BBB may also have pathogenetic implications in decompression sickness. Furthermore, increased BBB permeability to certain potentially useful antitumor agents, antibiotics, and other compounds under dysbaric conditions may provide the basis for a new therapeutic approach. This report concerns the influence of dysbaric exposure on BBB permeability to an antibiotic. Tetracycline (5-40 mg/kg) was intravenously injected in 22 experimental rabbits (subjected to air compression-decompression) and 17 controls (kept at ambient pressure). Fluorescence microscopy and spectrometry revealed significantly greater tetracycline concentrations in 72.7% of the experimental brains. With the 5 mg/kg dose, the mean tetracycline concentrations was 0.17 micrograms/g in control brains and 0.33 micrograms/g in experimentals. These results indicate that dysbaric exposure increases BBB permeability to tetracycline. It appears that BBB alteration is related to intravascular gas bubbles but is independent of the development of decompression sickness. The conclusions of this investigation are pertinent to brain pharmacotherapy and may provide some new insight into the mechanism of decompression sickness. They also point to potential risks connected with drug administration under dysbaric conditions that can alter BBB permeability.

Animals↗
PubMed1976

Effects of head-out water immersion on cardiorespiratory responses to maximal cycling exercise.

Our objectives were to determine effects of head-out immersion (HOI), scuba breathing, and water temperature on cardiorespiratory responses to maximal aerobic work. Measurements of VO2, VE, and heart rate (HR) were obtained on seven men (27 yr, 177 cm, 67 kg) as they performed the same upright bicycling exercise to exhaustion (4-5 min) in 23 degrees C air and 30 degrees C water. Maximal oxygen uptake (VO2 max) during HOI was 3.18 liters - min-1, which was not statistically different from the mean of 3.29 liters- min-1 in air. When compressed air was breathed via scuba during HOI, VO2 max was 3.12 liters- min-1 and not significantly different from that when room air was breathed and a low-resistance valve in water was used. HOI decreased VE by 15.7 liters - min-1 and HR by 10 beats (b) - min-1. Scuba breathing further reduced VE by 22.0 liters - min-1. Similar measurements were made on four of the subjects after 18 min of HOI in water temperatures of 35,30, and 25 degrees C. Water temperature had no significant affect on VO2 max, although HR was 8 b- min-1 lower in 30 degrees C and 15 b - min-1 lower in 25 degrees C as compared to 35 degrees C water. The results show that VO2 max was not significantly changed by HOI, scuba breathing, or brief exposures to 25, 30, and 35 degrees C water, despite significant reductions that occurred for VE and HR.

Adult↗
PubMed2005

Randomised trial of ambulatory oxygen in oxygen-dependent COPD.

Long-term oxygen therapy may limit a patient's ability to remain active and may be detrimental to the rehabilitation process. This study aimed to determine the effect of ambulatory oxygen on quality of life and exercise capacity in patients with chronic obstructive pulmonary disease fulfilling the usual criteria of long-term oxygen therapy. In a 1-yr, randomised, three-period, crossover trial, 24 patients (mean age 68 yrs; mean arterial partial pressure of oxygen at rest 7.1 kPa (53 mmHg)) were allocated to one of the six possible sequences generated by three interventions: 1) standard therapy (home oxygen therapy with an oxygen concentrator only); 2) standard therapy plus as-needed ambulatory oxygen; and 3) standard therapy plus ambulatory compressed air. The comparison of ambulatory oxygen versus ambulatory compressed air was double blind. The main outcomes were quality of life (Chronic Respiratory Questionnaire), exercise tolerance (6-min walk test) and daily duration of exposure to oxygen therapy. The trial was stopped prematurely after an interim analysis. On average, the patients used few ambulatory cylinders (7.5 oxygen cylinders versus 7.4 compressed air cylinders over a 3-month study period). Ambulatory oxygen had no effect on any of the outcomes. In conclusion, the current results do not support the widespread provision of ambulatory oxygen to patients with oxygen-dependent chronic obstructive pulmonary disease.

Aged↗
PubMed1978

An animal model simulating acute infective upper airway obstruction of childhood and its use in the investigation of croup therapy.

Twelve heartworm-free mongrel dogs (10 males, 2 females) mean weight 22.2 kg (range 17.7--28.2 kg) were sedated and placed in a supine position with the neck extended. A double tracheotomy was performed under sterile conditions. The first tracheotomy tube was inserted 2 cm above the sternum in the direction of the carina using a shortened Silastic American tracheotomy tube (id 10 mm); the second was inserted two cartilage rings proximal to the first and approximately 5 cm distal to the larynx. All animals were kept deeply anesthesized by repeated iv injections of 3--6 mg/kg pentobarbitone sodium so that all reflexes (in particular laryngeal and palatal) were abolished. After control translaryngeal pressure measurements were obtained, the vocal cords were visualized, and steam was introduced onto the through the cords for a mean of 10 sec from above. For 2 hr after this, repeat pressure measurements, as described above, were made. After an overnight stabilizing period, two to three of five randomly chosen air environments were passed over the larynx at 10 liters/min via the proximal tracheotomy, and four half-hourly pressure measurements taken with control periods of at least 2 hr, as described above, separating each experiment. Environments utilized were as follows: i) "cold dry" air, i.e., air at a mean temperature of 9 degrees, obtained by passing compressed air through a coil placed in a solution of alcohol/Dry Ice; ii) "cold moist" air, i.e., air as above, subsequently passed over cold water at a mean temperature of 11 degrees; iii) "warm dry" air, i.e., air at a mean temperature of 36.5 degrees, obtained by passing compressed air through a copper coil, immersed in hot water; iv) "warm moist" air at a mean temperature of 36 degrees, obtained by passing compressed air through a heated Puritan humidifier; v) "ultrasonically produced mist" at room temperature (24 degrees), produced by a De Vilbiss ultrasonic nebulizer 900, set at maximum output. Six 2-hr experimental periods were utilized for each regimen of treatment (i--v). The mean of the combined experimental resistance calculations for each environment were compared statistically with those of its similarly acquired control data, expressed as a positive or negative percentage change, and displayed as a histogram. In addition, the data from each experimental environment were compared with the others, and mean percentage changes from control against time were calculated. Results indicate no statistically significant change in resistance from control for ultrasonic mist or warm moist treatment regimens. Warm dry, cold dry, and cold moist treatments, however, all produced significant reductions in translaryngeal resistance (74%, 60%, and 54%, respectively), there being no difference between cold dry and cold moist and warm dry and cold dry. Significant differences between warm dry and cold moist treatments were obtained, the former decreasing translaryngeal resistance the greatest amount...

Acute Disease↗
PubMed1994

Nitrous oxide in early labor. Safety and analgesic efficacy assessed by a double-blind, placebo-controlled study.

BACKGROUND: Intermittent self-administered nitrous oxide has long had widespread use as an analgesic in labor, but its efficacy has not been adequately established. Questions about its effect on maternal oxygenation between labor contractions also have been raised. METHODS: Twenty-six women were recruited to participate in a randomized, double-blind, cross-over, placebo-controlled study to assess the effect of intermittent nitrous oxide inhalation on labor pain and maternal hemoglobin oxygen saturation (SPO2) during the first stage of labor. Visual analog scale pain scores for each of five consecutive labor contractions were measured after administration of either nitrous oxide or compressed air. RESULTS: Mean visual analog scale pain scores for five contractions were 5.1, 5.2, 5.7, 5.2, and 5.6 (nitrous oxide) and 4.9, 5.2, 6.1, 5.6, and 5.7 (compressed air). There were no statistically significant differences in pain when nitrous oxide as compared with compressed air was administered. Pain scores did not differ significantly over time as a function of inhaled substance (F = 0.41, P = 0.53). The mean lowest SPO2 observed between these contractions after self-administration of nitrous oxide and air were 97, 97, 97, 97, and 97% (nitrous oxide) and 97, 96, 96, 96, and 96% (compressed air). SPO2 was significantly higher after nitrous oxide administration (F = 8.8, P = 0.007). CONCLUSION: While intermittent self-administered 50% nitrous oxide in oxygen does not appear to predispose parturient women to hemoglobin oxygen desaturation, its analgesic effect has yet to be clearly demonstrated.

Adult↗
PubMed2006

The utility of supplemental oxygen during emergency department procedural sedation and analgesia with midazolam and fentanyl: a randomized, controlled trial.

STUDY OBJECTIVE: To determine whether supplemental oxygen reduces the incidence of hypoxia by 20% in study patients receiving midazolam and fentanyl for emergency department procedural sedation and analgesia. METHODS: Patients were randomized to receive either supplemental oxygen or compressed air by nasal cannula at 2 L per minute. Physicians were blinded to the gas used and end-tidal carbon dioxide (ETCO2) data. Respiratory depression was defined a priori as oxygen saturation less than 90%, ETCO2 level greater than 50 mm Hg, an absolute change from baseline of 10 mm Hg, or loss of the ETCO2 waveform. RESULTS: Of the 80 patients analyzed, 44 received supplemental oxygen and 36 received compressed air. Twenty supplemental oxygen patients and 19 compressed air patients met at least 1 criterion for respiratory depression. Six supplemental oxygen patients and 5 compressed air patients experienced hypoxia (P=.97; effect size 0%; 95% confidence interval -15% to +15%). Fourteen patients in each group met ETCO2 criteria for respiratory depression but were not hypoxic. Physicians identified respiratory depression in 8 of 11 patients who became hypoxic and 0 of 28 patients who met ETCO2 criteria for respiratory depression but who did not become hypoxic. There were no adverse events. CONCLUSION: Supplemental oxygen did not reduce (or trend toward reducing) the incidence of hypoxia in patients moderately sedated with midazolam and fentanyl. However, our lower-than-expected rate of hypoxia limits the power of this comparison. Blinded capnography frequently identified respiratory depression undetected by the treating physicians.

Adolescent↗