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PubMed1975

Measurement of partial pressure of gases in liquids by mass spectrometry.

The experimental setup of mass spectrometric determination of gas contents in liquids has been modified for continuous and discontinuous measurement of partial pressure of gases in liquids. The inlet system consists of a stainless steel capillary with slits covered by a silicone rubber membrane. Several gases can be measured simultaneously under static conditions and in flowing liquids. The measurement and calibration procedure is described. Results of the analysis of the test criteria, reproducibility, detection limit, response time, and depletion are presented. The difficulties in discontinuous measurement of oxygen in blood are explained by the complex permeation-diffusion process at the membrane and the form of the dissociation curve. With regard to solubility, physically dissolved gases can be determined without problems down to tensions of about 0.01 mm Hg. Continuous measurement of oxygen and carbon dioxide partial pressure in liquids, including blood, is possible with the described system.

Blood Gas Analysis↗
PubMed2003

[Occupational exposure of operating room staff to anesthetic gases during inhaled induction--a comparison with intravenous anesthesia induction].

BACKGROUND: The risk of occupational exposure to waste anesthetic gases still remains during inhaled induction. In this study we investigated how much we were occupationally exposed to anesthetic gases during induction period. METHODS: Twenty-six adult patients were induced with sevoflurane 5% using a face mask for three minutes and maintained with sevoflurane 1% after end-tracheal intubations (IH-Group). Twenty-two adult patients were induced with intravenous anesthetics and maintained with sevoflurane 1% after end-tracheal intubations(IV-Group). The concentration of sevoflurane was measured by Multi-gas Monitor 1302 (Bruel & Kjaer: Denmark) every 70 seconds. Sample gas was suctioned from breathing zone of anesthesiologists. All of our operating rooms are equipped with waste gas scavenging system. RESULTS: The peak concentration of sevoflurane is significantly higher in IH-Group (15.91 +/- 22.64 ppm) compared with IV-group (0.36 +/- 0.25 ppm). The period when sevoflurane concentration exceeded 0.5 ppm is significantly longer IH-Group (18.55 +/- 10.51 min.) compared to IV-Group (1.92 +/- 4.56 min.). CONCLUSION: The induction with intravenous anesthetics is a better method in order to reduce occupational exposure of anesthesiologists to anesthetic gases.

Adult↗
PubMed2004

Ventilator add-on for delivering PET tracer gases.

OBJECTIVES: The increasing use of PET for assessing cerebral blood flow, oxygen metabolism, and blood volume in critically ill patients has created a need for reliable technical solutions for delivering (15)O-tracer gases to mechanically ventilated subjects. Our objective was to create such a solution. METHODS: We designed a ventilator add-on unit that enables complex functional brain studies using labeled oxygen and carbon monoxide gases as tracers. The unit manages both steady-state and bolus inhalations, and the latter can be manually initiated using a remote trigger. All parts conducting breathing gases can be sterilized. The unit can be operated during both spontaneous pressure support breathing and volume-controlled ventilation. It supports the standard safety features and alarms of the ventilator and includes an overflow valve in the bolus reservoir. RESULTS: The count rate curves obtained using the new unit were similar to those from the standard bag-inhalation method. CONCLUSION: The unit we describe offers an economical and easily operated solution for providing uninterrupted ventilator treatment while performing PET brain studies, and the provided treatment meets intensive care criteria.

Brain↗
PubMed1992

[Experimental studies on the recovery of anesthetic gases].

The volatile anesthetic agents halothane, enflurane, and isoflurane are chlorofluorocarbons (CFC) and contribute to ozone depletion. Although the contribution is small, its importance is rising, as technical CFCs will be phased out according to the Montreal protocol (1987) and the London conference (1990) by the year 2000. Alternative procedures and CFC-free volatile agents such as des- and sevoflurane do not contribute to depletion of the ozone layer, but will not replace standard methods using volatile anesthetic agents in the near future. METHODS. In an experimental setup, we filtered anesthetic waste gases from scavenging systems of rebreathing circles by activated carbon filters. The filtered substances were desorbed by a heat chamber and condensed in a cold trap. RESULTS. By this method, it was possible to retrieve 50%-60% of the applied gases. Gas chromatographic analysis showed halothane containing traces of pollutants and isoflurane and enflurane as pure substances. DISCUSSION. The retrieval of anesthetic waste gases is easy; no sophisticated technical equipment is necessary. Purity of substances could make recycling possible and offer a method to avoid environmental pollution by volatile anesthetics.

Anesthetics↗
PubMed1989

[Effects of hypopressure on blood gases and spirograms of patients suffering from chronic respiratory failure].

We examined the effects of hypopressure on blood gases and spirograms of patients suffering from chronic respiratory failure, and compared them with those of normal subjects, using the environmental control unit (ECU). The patients consisted of 2 with idiopathic interstitial pneumonia (IIP), 1 with pulmonary fibrosis due to RA, 3 with bronchiectasis, 2 with chronic bronchitis and 1 with diffuse panbronchiolitis (DPB). We examined their blood gases and spirograms under the condition of 760 mmHg pressure, 25 degrees C temperature and 60% humidity. Then the pressure of ECU decreased to 670 mmHg in 20 minutes, while the temperature and humidity were kept the same. The patients stayed in the hypopressured ECU for 1 hour, and were reexamined. The pressure of 670 mmHg is that of an altitude of about 1,000 m and that of the cabin pressure of commercial aircraft flying at about 9,000 m. The PaO2 of the patients decreased from 74.7 +/- 13.8 torr to 61.8 +/- 9.5 torr significantly. We found, however, the significant decrease of PaO2 in normal subjects from 97.2 +/- 7.8 torr to 80.4 +/- 6.5 torr under the same conditions. The rates of the decreased gases were almost same in both groups. Some patients showed remarkable decreases in VC and FEV1.0 under the hypopressure. No patients or control subject complained of subjective symptoms.

Adult↗
PubMed1987

Free radical reactions and the inhibitory and lethal actions of high-pressure gases.

This study was designed to test whether free radicals are involved in the deleterious effects of compressed gases on cells. The actions of xenon, nitrous oxide, argon, nitrogen, helium, and oxygen and their effects on the toxicity of paraquat (methyl viologen) were studied using Escherichia coli. Growth of E. coli in trypticase-soy broth in an atmosphere of 1.36 MPa (13.6 atm) N2O resulted in an induction of superoxide dismutase (SOD). In addition, when SOD was induced by oxygen, the resulting cells had increased resistance to the killing action of N2O. The toxicity of paraquat was increased in the presence of N2O but not He, N2, or Ar. However, addition of any of the latter three gases to N2O resulted in increased toxicity of paraquat beyond that due to N2O alone. Oxygen is known to increase the reaction of paraquat radicals within cells and to reduce leakage of the radicals out through the cell membrane. N2O and Xe seem to have this same action, and He, N2, or Ar could enhance the actions of N2O, Xe, or O2. The data indicate that the inhibitory and lethal actions of these gases may be due to enhanced reactivity of radicals with cell components and reduced leakage of the radicals to the environment.

Animals↗
PubMed1986

Respiratory gases.

Respiratory gases have access to the human circulation by diffusing through alveolar walls into pulmonary capillaries. Because of this circulatory access, these gases can act like other types of drugs, and can produce effects both locally in the lungs and systemically in distant organs or tissues. This article reviews the metabolism, pharmacology, and therapeutic use of the three most common gases used in the practice of respiratory medicine: oxygen, carbon dioxide, and helium.

Carbon Dioxide↗
PubMedDate not supplied

An in vitro model for the exposure of lung alveolar epithelial cells to toxic gases.

An in vitro model of lung alveolar tissue was developed by growing rat lung epithelial cells of Type II origin on hydrated collagen gels and subsequently maintaining the cultures at an air/liquid interface. The cultures provide a system to expose lung cells directly to toxic aerosols, fumes and gases. Nitrogen dioxide (NO2) was used to test the responsiveness of the cultures to toxic gases. Exposure to NO2 resulted in cytotoxicity and morphological alterations similar to those found in vivo, but at lower doses. Cell viability was analyzed by trypan blue dye exclusion, clonal survival and 3H-lysine incorporation. Dose-response relationships were determined at NO2 concentrations from 0-6.0 ppm (one hr exposure, room temperature) using cell viability assays. Decreased cell viability also resulted from increasing the time of exposure to 6 ppm of NO2 for up to one hr. This lung cell test system provides a rapid and economical system for the short-term toxicological testing of toxic gases, fumes, and aerosols.

Aerosols↗
PubMedDate not supplied

Toxic gases used in the microelectronics industry.

Toxic gases are among the most dangerous materials used in manufacturing semiconductors and related devices. The storage, handling, and disposal of these gases pose a major hazard to workers and to communities located near high-technology companies. It must be anticipated that accidents, acts of terrorism, and natural calamities will result in exposure. Flammability, corrosiveness, and concentration must be considered, as well as the immediate danger to life and known human health effects of the gases used.

Air Pollutants, Occupational↗
PubMed1985

Dramatic changes in blood gases that are unrelated to arterial pH or cerebral oxygen delivery during endotoxin shock in conscious rats.

In preliminary studies we demonstrated an effect of endotoxin on arterial blood gases that appeared to be related to the dose of endotoxin used and unrelated to changes in arterial pH. In the present study we tested the hypothesis that these changes in blood gases result from decreased oxygen delivery to central respiratory control areas. PO2 significantly rose from a pre-endotoxin value of 91.4 +/- 1.5 (mean +/- SEM) to 97.5 +/- 1.7, 104.0 +/- 0.8, and 108.4 +/- 0.9 at 10, 30, and 60 minutes, respectively, after administration of 6 mg/kg endotoxin and from 93.8 +/- 3.1 to 105.2 +/- 2.6, 118.7 +/- 1.4, and 121.0 +/- 2.8, respectively, after administration of 10 mg/kg endotoxin. PCO2 fell significantly from a pre-endotoxin value of 38.3 +/- 1.2 to 28.6 +/- 0.6 and 24.5 +/- 1.9 at 30 and 60 minutes post-endotoxin, respectively, in 6-mg/kg-treated rats, and from 40.5 +/- 2.1 to 30.7 +/- 4.5, 20.1 +/- 3.9, and 19.3 +/- 1.0, respectively, at 10, 30, and 60 minutes post-10 mg/kg endotoxin. The only significant change (decrease) in pH occurred at 60 minutes after 10 mg/kg treatment. In 10-mg/kg-treated rats, serum lactate rose significantly over time, while HCO-3 decreased. Heart rate was increased significantly (472 +/- 9.6) from a pre-10 mg/kg endotoxin value of 373 +/- 11.8 by 10 minutes post-endotoxin and remained elevated throughout the experiment. Cerebral medullary/pontine blood flow, mean arterial blood pressure, and respiratory rate were not significantly altered by endotoxin administration. Hemoglobin concentration and arterial oxygen content were significantly increased after 10 mg/kg endotoxin. These findings indicate that decreased oxygen delivery to central respiratory control areas is not a cause of the observed dramatic changes in blood gases.

Acid-Base Equilibrium↗
PubMed1985

The effect of ventilation on systemic blood gases in the presence of left ventricular ejection during cardiopulmonary bypass.

The effect of pulmonary ventilation upon systemic arterial blood gases during cardiopulmonary bypass in the presence of left ventricular ejection was evaluated in 20 adult male patients undergoing coronary artery bypass grafting. Following rewarming, establishment of a sinus rhythm, and production of a pulse pressure of at least 20 mm Hg on the arterial pressure trace caused by left ventricular ejection, arterial blood gases were obtained from the arterial and venous extracorporeal circuits and the radial arterial cannula. Patients were then randomly assigned to a nonventilation (n = 10) or a ventilation (n = 10) group. The ventilation group was given 10 breaths/min with 100% oxygen at a tidal volume of 10 ml/kg. Whereas the nonventilation group received apneic oxygenation at zero end-expiratory pressure. After 5 minutes the arterial blood gas data were again obtained. Significant findings (p less than 0.05) included decreases in systemic carbon dioxide tension and increases in systemic pH in the ventilation group and decreases in systemic oxygen tension in the nonventilation group. Although the changes in the arterial blood gases were significant, these changes occurred well within the limits of clinical acceptability. It is concluded that left ventricular ejection for short periods during full cardiopulmonary bypass does not necessitate pulmonary ventilation.

Aged↗
PubMedDate not supplied

Arterial blood gases in the coronary care unit. Part I.

Blood gas analyses are frequently helpful and at times vital in the management of patients who develop complications during an acute myocardial infarction. This vignette discusses the arterial blood gases when congestive heart failure complicates an acute myocardial infarction. Blood gas measurements are generally obtained for two principle reasons: (1) to determine if the patient is well oxygenated--Po2 and O2 arterial gas measurements, and (2) to determine the patient's acid base status (a) using respiratory component of acid base status--PCO2 measurement, (b) using metabolic component of acid base status--HCO-3 measurement, and (c) using both a and b. Arterial blood gases are preferred over venous blood gases. Venous blood gives information relative to the extremity it drains and may be misleading if the extremity is cold, clammy, or underperfused.

Arteries↗
PubMed1980

[Competitive study of the effects of naloxone and of almitrine on fentanyl analgesia in the anesthetized dog: effects on the muzzle opening reflex and blood gases].

UNLABELLED: The search for a technique making it possible to dissociate the analgesia and ventilatory depression of central analgesics led to a comparison of the effects of naloxone, a specific morphinomimetic antagonist, with almitrine, a ventilatory stimulant with a peripheral action, on muzzle opening reflex and blood gases. Five male dogs (Beagles, aged one year), anaesthetised with Alfetesine were treated separately with the two drugs used alone and after fentanyl analgesia (injection of fractionnated doses up to the threshold of apnoea). The association of the two drugs was also tested in tyhe dog after analgesia. The parameters studied were muzzle opening reflex, as an indication of analgesia, and blood gases, and were observed for 45 minutes, including 15 minutes control. RESULTS: 1 - The intravenous injection of 1,2 mg of naloxone had the effect of increasing the surface area of muscle potentials with a maximum of 7 per cent (p 0.001) at the 15 th minute. By contrast, no significant change in blood gases was seen. In the same dogs given fentanyl analgesia, naloxone not only reversed respiratory depression but had a stimulatory effect on MOR reaching 7 per cent (p 0.001) at the 30 th minute. 2 - The effects of 1 mg.kg-1 of almitrine were characterised by a fall in MOR for a period equal to that of the study and a minimum of 7.8 per cent (p 0.001) at the 20 th minute. At the same time, marked ventilatory stimulation was seen. PO2 rose by 22.7 per cent (p 0.02) at the 5 th minute. PCO2 fell during the 30 minutes studied with a minimum of 39.6 per cent (p 0.01) at the 20 th minute. Almitrine did not antagonise the depression of MOR caused by fentanyl but reversed the respiratory depression of the analgesic, increasing PO2 by 26 per cent (p 0.01) and decreasing PCO2 by 25.7 per cent (p 0.01). 3 - The combination of both drugs cancelled out the abolition of the reflex by fentanyl then facilitated it up to 24.7 per cent (p 0.001) in comparison with the animal not receiving any analgesic. By contrast, the ventilatory action of almitrine was not potentialised by naloxone. In view of these data, and in the absence of any emergency, the choice of naloxone as an antagonist of ventilatory depression of central analgesics should not be preferential in order to avoid the rebound effect.

Almitrine↗
PubMed1981

Studies on the influence of combustion exhaust gases and the products of their reaction with ammonia on the living organism. I. The influence on DNA, RNA and soluble proteins in the liver of guinea pig.

The paper presents the behaviour of DNA, RNA and soluble proteins in whole homogenate as well as the nuclear, mitochondrial and postmitochondrial liver fractions in guinea pigs exposed to combustion exhaust gases and the products of their reaction with ammonia. A decrease of RNA level was found in the liver of animals exposed to combustion exhaust gases together with a decrease of soluble proteins in all the studied fractions. On the other hand, in the group of animals subjected to the action of neutralization products of combustion gases by ammonia, the studied components were increased. This increase may be the result of the simultaneous action of industrial noise.

Ammonia↗
PubMed1981

Studies on the influence of combustion exhaust gases and the products of their reaction with ammonia on the living organism. II. The influence on aspartate aminotransferase (AspAT) and alanine aminotransferase (AiAt) activities in the liver of guinea pig.

The behaviour of aspartate aminotransferase (AspAT) an alanine aminotransferase (AIAT) in the whole homogenate and subcellular liver fractions of guinea pigs exposed to combustion exhaust gases and the neutralization products of these gases is presented in this paper. In the liver of animals exposed to the chronic action of combustion exhaust gases a decrease of both enzyme activities in the whole homogenate as well as in the subcellular fractions could be noted. Statistically significant changes are shown by AspAT. In the group of animals subjected to the action of neutralization products an increase of AIAT activity was observed. The activity of AspAT still shows a decrease, but less distinct in comparison with group I. An exception here is the mitochondrial fraction in which the AspAT activity is distinctly increased.

Alanine Transaminase↗
PubMed1982

Patterns of interaction of effects of light metabolically inert gases with those of hydrostatic pressure as such--a review.

This review of available literature attempts to interpret net effects of metabolically inert light gases (He, H2, and Ne) as the resultant of hydrostatic pressure and intrinsic pharmacological effects associated with exposure to these gases, and to assess the relative importance of each component with respect to a number of biological responses. A common pattern is recognizable for pressure reversal of anesthesia, high pressure convulsions, high pressure bradycardia, and certain characteristics of liposome model systems. Using the method of analysis proposed, these lightest gases can be shown to conform to the pattern of relation of potency to physical properties characteristic of more potent gaseous anesthetics, including N2, N2O, and Xe. The relations between effect produced and partial pressure of the acting gas are approximately linear to total pressures of 100 ATA for anesthesia or pressure reversal of anesthesia and (or to a much smaller extent) for the liposome model systems, but not for high pressure convulsions. As a result of these general factors no single gas can be expected to neutralize the effects of hydrostatic pressure with regard to all of the biological responses tested over any significant pressure range. A series of experiments with single cells and tissue cultures have revealed interactions between high pressure and inert gas that do not conform to the pattern set by the responses mentioned so far. These responses cannot yet be shown to constitute a homogeneous group and may represent at least two subgroups. Responses falling into this second heterogeneous category include cell motility, development of cell abnormalities and lysis, and cell and perhaps virus replication or multiplication. The implication of these results for the formulation of biophysical hypotheses to explain interactions between inert gas and high pressure, for considerations of high pressure effects as a safety hazard, and for the problem of experimental approaches to the study of pressure acclimation are discussed briefly.

Anesthesia, Inhalation↗
PubMed1984

Recovery of waste anesthetic gases.

The problem of waste anesthetic gases must be addressed because of potential health hazards. However, solutions must be considered within a larger context than that of the operating room or dental suite. The impact of shifting wastes from the hospital into the atmosphere must be examined for both ecologic and ethical implications. A hypothetic situation has been proposed in which the waste anesthetics are dealt with by recovery and reuse. Although potential costs and benefits can be discussed, overall feasibility and desirability cannot be assessed until certain questions are addressed. Are waste anesthetic gases an atmospheric pollutant with impact sufficient to cause concern? If not, do the economic considerations of recycling exhausted anesthetic and respiratory gases warrant implementation? Anesthesiologists need to consider these issues within the constraints of the environments in which they practice. The problem will exist as long as inhalation anesthesia is in use. Solution should not create new problems.

Air Pollutants↗
PubMedDate not supplied

Neurobehavioral functions in operating theatre personnel exposed to anesthetic gases.

Neurobehavioral functions in paramedical operating theatre personnel were assessed in a cross-sectional survey. Sixty-two subjects (40 males and 22 females) occupationally exposed to anesthetic gases were examined and compared to 46 unexposed hospital workers (18 males and 28 females). The Simple Reaction Time (SRT) test was selected from the MANS battery (Milan Automated Neurobehavioural System). In order to evaluate acute and subacute types of effects on performance, the test was administered before and after the work shift, at the beginning and at the end of the working week. In addition, the complete battery was administered during one working day without exposure to anesthetic gases. On the last day of the working week, atmospheric nitrous oxide (N2Oa) ranged from 7 to 553 ppm (geometric mean 62.6), atmospheric ethrane (ETHa) ranged from 0.1 to 18.8 ppm (geometric mean 1.3), and urinary N2O (N2Ou) ranged from 4 to 297 micrograms/l (geometric mean 26.8). An impairment of performance on the SRT test was observed at the end of the working week in subjects exposed to anesthetic gases compared to controls. This alteration was observed also considering only the subjects exposed to less than 55 micrograms/l (which is the Italian exposure limit for N2Ou, equivalent to 100 ppm for N2Oa). No significant differences were observed for the other psychometric tests. No dose-effect relationships where found between SRT test score and the indicators of exposure (N2Oa, ETHa, N2Ou).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗