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At least 1,009 records · Page 56Linked to original sources
PubMed1981

Metabolic effects of obstetric regional analgesia and of asphyxia in the newborn infant during the first two hours after birth. III. Adjustment of arterial blood gases and acid-base balance.

Effects of obstetric regional analgesia and of asphyxia on the arterial blood gases and acid-base balance in the first two hours after birth were investigated in 85 newborn infants divided into a control group, an asphyxia group and a continuous epidural, an intermittent epidural and a paracervical + pudendal block group. Lidocaine was the drug used in the analgesia groups. In the asphyxia group the metabolic acidosis decreased and pH was normalized to the level of the control group between 10 and 30 min after birth. During this period in the asphyxia group PaO2 was higher than and PaCO2 similar to the corresponding control values. Compared with the control group, in the regional analgesia groups the metabolic acidosis tended to be less extensive and PaO2 higher, whereas PaCO2 was similar. A lower packed red cell volume in the asphyxia and in the regional analgesia groups, probably due to differences in placental transfusion, may have had influence on the results. Within the regional analgesia groups infants with hyperglycemia showed signs of an increased metabolic acidosis while infants with hypoglycemia had low base deficit and lactate values supporting the assumption that neonatal blood glucose concentration may reflect perinatal distress.

Acid-Base Equilibrium↗
PubMed1994

Effects of salbutamol inhalations on transcutaneous blood gases in children during the acute asthmatic attack: from acute deterioration to recovery.

Nine children, 7-16 years of age, were studied repeatedly during an acute asthmatic attack, from acute deterioration to recovery. The transcutaneous blood gases, forced expiratory volume in 1 s (FEV1) and maximum expiratory flow when 25% of vital capacity remained to be expelled (MEF25) were monitored before and after salbutamol inhalation. The flow-volume variables were markedly impaired in the acute phase but improved gradually by the time of recovery. The transcutaneous PO2 (tcPO2) decreased in the acute and early recovery phase but improved by the late recovery phase. In the acute phase, the salbutamol inhalations increased the FEV1, indicating an improvement in central airway function, but also reduced the MEF25 and tcPO2 in some of the children. The changes in tcPO2 after the inhalations correlated with the changes in MEF25 (p < 0.001), thereby indicating a common denominator, probably the condition of the peripheral airways. In the recovery phase, the FEV1, MEF25 and tcPO2 improved after the inhalations (p < 0.05). In conclusion, transcutaneous PO2 can be used to evaluate the effects of treatment in children with acute asthmatic symptoms and may add information about peripheral airway function which may prove particularly valuable in small children where few methods are available for such measurements.

Acute Disease↗
PubMed1999

The effects of training on ventilation and blood gases in exercising thoroughbreds.

The effects of training on ventilation and blood gases during exercise were investigated in 6 clinically normal, detrained Thoroughbred horses. They underwent a 16 week training programme similar to the type frequently used for Thoroughbred racehorses in Great Britain. Standardized treadmill exercise tests (2 min canter at 8 and 10 m/s C8 and C10[ and 2 min gallop at 12 m/s [G12], on a level surface) were performed prior to and after 16 weeks of training. Respiratory flow rates were measured using ultrasound flow transducers. Blood samples were drawn from a transverse facial artery and the right atrium. Minute ventilation, respiratory frequency and tidal volume were not significantly altered by training. Peak inspiratory flow rate was lower following training at 8 and 10 m/s, but not at 12 m/s. Arterial oxygen tension was decreased during trot and canter following training. Blood lactate concentration post G12 decreased following training (10.5 +/- 2.2 mmol/l vs. 7.7 +/- 2.2 mmol/l; P < 0.05). The increase in the degree of exercise-induced arterial hypoxaemia following training may reflect a lack of pulmonary adaptation to training in the face of improved cardiovascular and muscular function.

Animals↗
PubMed1984

Effects of body temperature on ventilation, blood gases and acid-base balance in exercising fowl.

In order to determine the influence of hyperthermia on respiratory, blood gas and acid-base changes in exercising birds, we exercised domestic fowl on a treadmill at ambient temperatures of 5, 20, 30 and 35 degrees C for 10 min at graded running speeds up to 4.3 km.h-1. Ventilation and gas exchange were measured continuously and arterial blood gases, pH and the concentration of lactic acid in arterial blood were measured in samples taken during the last minute of each run. During exercise at 5 degrees C rectal temperature did not change significantly from rest (isothermic condition) and there was no sign of thermal influence on respiratory pattern, such as was observed at higher ambient temperatures. At any given running speed, increased ambient temperature caused increased ventilation by an increase in respiratory frequency (f) together with a decrease in tidal volume (VT). Under isothermic conditions, at low running speeds, birds maintained an isocapnic hyperpnoea: arterial PCO2, PO2 and pH and oxygen extraction were unchanged. However at higher speeds (ca. greater than 2.5 km.h-1) some hyperventilation occurred with subsequent falls in arterial PCO2 and oxygen extraction. Arterial pH also fell significantly (P less than 0.01). During hyperthermic exercise, oxygen extraction, arterial PCO2 and bicarbonate concentration all fell significantly (P less than 0.01) and progressively with increasing work load, and birds hyperventilated at all running speeds. This produced a significant arterial hypocapnia and alkalosis at the lower speeds (P less than 0.05) but this was replaced by a hypocapnic metabolic acidosis at the higher running speeds. Blood lactate concentration rose steeply at speeds above ca. 2.5 km.h-1 but arterial pH fell by only 0.1 units or less partly as a result of buffering by blood bicarbonate. It is concluded that both hyperthermia and lactacidosis are causes of hyperventilation and arterial hypocapnia during heavy running exercise in birds. However, ventilatory adjustments similar to those observed in resting hyperthermic birds, viz. increased f and reduced VT prevent severe arterial hypocapnia from occurring in hyperthermic exercising birds.

Acid-Base Equilibrium↗
PubMed2003

Simultaneous reconstruction of flow and temperature cross-sections in gases using acoustic tomography.

This paper describes the use of air-coupled ultrasonic tomography for the simultaneous measurement of flow and temperature variations in gases. Air-coupled ultrasonic transducers were used to collect through-transmission data from a heated gas jet. A transducer pair was scanned in two-dimensional sections at an angle to the jet, and travel time and amplitude data recorded along various paths in counter-propagating directions. Parallel-beam tomographic reconstruction techniques allowed images to be formed of variations in either temperature or flow velocity. Results have been obtained using heated jets, where it has been shown that it is possible to separate the two variables successfully.

Acoustics↗
PubMed1966

Blood gases: continuous in vivo recording of partial pressures by mass spectrography.

Gases were sampled directly from circulating blood through a membrane at the tip of an intravascular cannula that was connected to the analyzing section of a mass spectrometer. Partial gas pressures and membrane permeability determine gas flow into the spectrometer. Arterial carbon dioxide and oxygen pressures were simultaneously recorded in an anesthetized animal subjected to various respiratory maneuvers.

Animals↗
PubMed1987

Widespread occurrence of bacterial thiol methyltransferases and the biogenic emission of methylated sulfur gases.

A majority of heterotrophic bacteria isolated from soil, water, sediment, vegetation, and marine algae cultures methylated sulfide, producing methanethiol. This was demonstrated with intact cells by measuring the emission of methanethiol with a sulfur-selective chemiluminescence detector, and in cell extracts by detection of sulfide-dependent thiol methyltransferase activity. Extracts of two Pseudomonas isolates were fractionated by gel-filtration and ion-exchange chromatography, and with sulfide as the substrate a single peak of thiol methyltransferase activity was seen in each case. Extracts of several bacterial strains also contained thiol methyltransferase activity with organic thiols as substrates. Thus, S-adenosylmethionine-dependent thiol methyltransferase activities are widespread in bacteria and may contribute to biogenic emissions of methylated sulfur gases and to the production of methyl thioethers.

Bacteria, Aerobic↗
PubMed2004

Correlation of simultaneously obtained capillary, venous, and arterial blood gases of patients in a paediatric intensive care unit.

AIMS: To investigate the correlation of pH, partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2), base excess (BE), and bicarbonate (HCO3) between arterial (ABG), venous (VBG), and capillary (CBG) blood gases. METHODS: Patients admitted to the paediatric intensive care unit (PICU) in Cukurova University between August 2000 and February 2002 were enrolled. RESULTS: A total of 116 simultaneous venous, arterial, and capillary blood samples were obtained from 116 patients (mean age 56.91 months, range 15 days to 160 months). Eight (7%) were neonates. Sixty six (57%) were males. pH, PCO2, BE, and HCO3 were all significantly correlated in ABG, VBG, and CBG. Correlation in PO2 was also significant, but less so. Correlation between pH, PCO2, PO2, BE, and HCO3 was similar in the presence of hypothermia, hyperthermia, and prolonged capillary refilling time. In hypotension, correlation in PO2 between VBG and CBG was similar but disappeared in ABG-VBG and ABG-CBG. CONCLUSIONS: There is a significant correlation in pH, PCO2, PO2, BE, and HCO3 among ABG, VBG, and CBG values, except for a poor correlation in PO2 in the presence of hypotension. Capillary and venous blood gas measurements may be useful alternatives to arterial samples for patients who do not require regular continuous blood pressure recordings and close monitoring of PaO2. We do not recommend CBG and VBG for determining PO2 of ABG.

Adolescent↗
PubMed1983

Effects of artificial surfactant on lung function and blood gases in idiopathic respiratory distress syndrome.

We have investigated the effect of giving two 25 mg doses of dry surfactant powder to the airways of 10 preterm babies with severe idiopathic respiratory distress syndrome requiring intermittent positive pressure ventilation. No useful change in static total compliance or blood gases was seen. We conclude that dry surfactant powder does not have a role in the management of severe idiopathic respiratory distress syndrome.

Carbon Dioxide↗
PubMed1984

Cord blood gases, birth asphyxia, and intraventricular haemorrhage.

The relation between intraventricular haemorrhage, Apgar scores, and cord blood gases was determined prospectively in 150 infants of 34 weeks' gestation, or less. Although there was no significant relation between birth asphyxia and subsequent haemorrhage, a consistent trend for lower Apgar scores in infants who developed haemorrhage was shown.

Apgar Score↗
PubMed1992

Membrane humidification--a new method for humidification of respiratory gases in ventilator treatment of neonates.

A humidifier system for neonatology that functions according to the 'membrane humidification' principle was subjected to a performance test in our laboratory. Humidification and heating of the respiratory gases took place in a module consisting of a net of hollow fibres placed inside the incubator. In 18 measurement combinations flow, respiratory gas temperature, and incubator temperature were varied. At respiratory gas temperatures within the range of 33-37 degrees C the minimum international standard for the absolute air humidity in the respiratory gas was achieved or exceeded in all measurements. No controlled clinical tests regarding the importance and long term effects of different temperatures and different humidity levels in the inspiratory air are yet available for the ventilation treatment of neonates.

Evaluation Studies as Topic↗
PubMed1993

Rebreathing expired gases from bedding: a cause of cot death?

The reported association of cot death and sleeping prone could be due to rebreathing of expired gases. A mechanical model simulating the respiratory system of an infant, exhaling warm humidified air with an end tidal carbon dioxide of 5%, has been used to investigate this. Some commonly used bedding materials caused an accumulation of carbon dioxide of 7% to over 10% with the model lying face down. This phenomenon persisted even with the head inclined at 45 degrees, but only on very soft materials, and could be a cause of cot death in a baby unresponsive to asphyxial blood gas changes. A coir fibre mattress allowed complete dispersal of exhalate as did a rubber sheet between any mattress and the covering sheet.

Asphyxia↗
PubMed1973

Spinal cord blood flow in dogs. 2. The effect of the blood gases.

The effect of CO(2) on the spinal cord blood flow was investigated in nine dogs. The flow was closely correlated with the paCO(2) and at about 85 mmHg was double the normocarbic flow. The effect of pO(2) was studied in a further nine dogs. Hypoxia markedly increased the flow which was maximal at paO(2) 30-40 mmHg. The vasoconstrictor effect of hypocarbia was absent or decreased in hypoxia. The response of the cord vessels to the blood gases was very similar to that of the brain.

Animals↗
PubMed1987

Effect of acetazolamide on blood gases and 2,3 DPG during ascent and acclimatization to high altitude.

Blood gases and red cell 2,3 DPG concentrations were measured during ascent and a stay for 6 days at 4846 m in 20 subjects. Acetazolamide improved Pa,O2 and reduced pH and Pa,CO2. 2,3 DPG concentrations were lower in the acetazolamide group during ascent and at high altitude. However, 2,3 DPG concentrations were significantly greater at high altitude in both the acetazolamide and placebo groups compared with low altitude. The acetazolamide group remained different from the placebo group during the stay at high altitude with higher Pa,O2, lower PaCO2, lower pH and lower 2,3 DPG concentrations.

2,3-Diphosphoglycerate↗
PubMed1989

Toxic gases.

An overview of the widespread use of gases and some volatile solvents in modern society is given. The usual circumstances in which undue exposure may occur are described. The most prominent symptoms and general principles of diagnosis and treatment are given and are followed by more specific information on the commoner, more toxic materials. While acute poisonings constitute the greater part of the paper, some indication of chronic disorders arising from repeated or prolonged exposure is also given.

Acute Disease↗
PubMed1984

Effect of upper airway carbon dioxide on ventilation and blood gases in the awake pony.

Carbon dioxide concentrations were increased during expiration in the upper one-half of the trachea, pharynx, and nasal sinuses to determine if elevation of upper airway CO2 would alter breathing or arterial blood gases in the awake pony. Carbon dioxide (100%) was injected into the midcervical trachea via a chronically implanted transcutaneous cannula during the first part of the animal's expiration. This maneuver elevated upper airway expiratory CO2 concentrations but prevented any exogenous CO2 from entering the lung and being absorbed into the arterial blood. Twelve experiments were performed on six ponies in which upper airway CO2 was elevated 2, 4, and 6% above the normal expired CO2 concentrations. Tidal volume increased in a dose dependent manner during upper airway CO2 exposure, but total ventilation was unchanged from base-line measurements made while the animal breathed room air. Arterial Po2 also increased during upper airway CO2 administration, reaching a mean value 6 Torr (1 Torr = 133.322 Pa) greater than the base-line values at the +6% CO2 exposure. We conclude that upper airway CO2 exposure alters breathing pattern slightly (increases tidal volume) and increases arterial PO2 in the awake pony.

Animals↗
PubMed1995

Role of intracellular pH in relaxation of porcine tracheal smooth muscle by respiratory gases.

Hypercapnia and hypoxia both relax airway smooth muscle, but the mechanisms responsible are poorly understood. Because hypercapnia and hypoxia can each decrease intracellular pH (pHi) and acidosis can inhibit Ca2+ channels, we hypothesized that decreased pHi mediates relaxation of trachealis muscle by each of these respiratory gases. To examine the relationship between pHi and tone, we measured isometric tension, bath pH, and fluorescence intensity (540 nm) in porcine tracheal smooth muscle strips loaded with 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein and excited alternately with 440- and 500-nm light. Strips equilibrated in Krebs-Henseleit solution bubbled with 95% O2-5% CO2 were contracted with carbachol and then relaxed with either 95% N2-5% CO2 or 93% O2-7% CO2. The ratio of fluorescence intensity at 500 nm to 440 nm was calibrated vs. pHi with use of nigericin. Baseline pHi was 7.19 +/- 0.03 (n = 13). Hypoxia decreased active tension by approximately 60% but did not change pHi. Hypercapnia induced decreases in tension that were associated with substantial decreases in pHi. Thus, decreased pHi does not mediate hypoxic relaxation, but the relaxation during physiologically relevant increases in CO2 concentration is associated with significant cellular acidification.

Animals↗