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PubMed1978

Blood flow distribution in the duck lung and its control by respiratory gases.

Blood flow to subunits of the lung was studied in the duck by use of radioactive microspheres. In spontaneously breathing, unanesthetized animals (series I) neopulmo was slightly better perfused than the average lung and along the paleopulmonic parabronchi, blood flow was found to decrease in the direction of ventilatory gas flow and thus of decreasing PO2 and increasing PCO2 in lung gas. The effects of respiratory gases on regional lung perfusion were investigated in unidirectionally ventilated animals (series II) in which gas mixtures offered to both lungs could be controlled independently. Local hypoxia resulted in reduction of local blood flow, whereas effects from hyperoxia or CO2 could not be substantiated. Reversal of the direction of unidirectional ventilatory flow (series III), and thus reversal of the profiles of respired gas concentrations along the parabronchi, suggest that the inhomogeneity in blood flow observed in spontaneously breathing animals of series I can only in part be explained as an acute adjustment to the local hypoxia. Calculations show that this inhomogeneity of blood flow constitutes an only minor impairment of the overall gas exchange efficacy of the parabronchial lung.

Animals↗
PubMed1988

Evaluation of a blood sample-transfusion protocol in rats: blood gases, renin, and ACTH.

The present study evaluated a protocol for drawing large volumes of blood over an acute time frame in conscious cannulated rats with blood from cannulated donor rats simultaneously infused to maintain isovolemia. During time control (n = 6), three successive 1.5-ml blood samples were drawn at 10-min intervals with equal volumes of donor blood infused simultaneously. One milliliter of blood was drawn quickly and saved for analysis followed by an additional 3 ml of blood withdrawal to total a 15-ml/kg hemorrhage. Two subsequent 1.5-ml samples were replaced with autologous (hemorrhage) blood. During hypoxia inspired O2 was decreased to 10% after the first sample-transfusion. The sampling-transfusion protocol (time control) had no effect on blood pressure (MAP), hematocrit (Hct), blood gases, renin, or adrenocorticotropic hormone (ACTH). Hemorrhage resulted in a significant decrease in MAP, Hct, base excess, and arterial PCO2 and an increase in arterial PO2, renin activity, and ACTH. Ten percent O2 resulted in significant hypoxemia, respiratory alkalosis, and a small degree of hypotension at the 20-min sample with no change in renin and a moderate increase in ACTH. The consistency of the results with previous studies confirms the utility and efficiency of large sample-transfusion protocols for the study of blood gas and endocrine dynamics in conscious rats.

Adrenocorticotropic Hormone↗
PubMed1975

Pulmonary ventilation, blood gases, and blood pH after training of the arms or the legs.

In two groups of young healthy subjects who performed arm training (N = 5) and leg training (N = 5), respectively, the respiratory adaptation to submaximal exercise with trained and nontrained muscle groups was compared by measurement of the ventilatory equivalent (Ve/Vo2, pH, and blood gases (Pco2, Po2, and So2) in arterial blood and in venous blood from exercising extremities. After training Ve/Vo2 was significantly reduced during exercise with trained muscles, but unchanged during exercise with nontrained muscles. The reduction in Ve/Vo2 was closely related to a less pronounced increase in heart rate and in arterial lactate content, but showed no quantitative correlation to changes in arterial adaptations in trained muscles are mainly responsible for the reduction in Ve/Vo2. After training during exercise with trained as well as nontrained muscles a shift to the right of the blood oxygen dissociation curve occurred as extremities was lower while corresponding Po2 was higher.

Adult↗
PubMed1979

Mean alveolar gases and alveolar-arterial gradients in pulmonary patients.

In view of uncertainties about the best way to estimate mean alveolar gases in patients with ventilation-perfusion inequalities, three different methods were evaluated on 54 patients. 1) O2 and CO2 were recorded by mass spectrometer on an O2 (x)-CO2 (y) diagram. The coordinates at the intersect of the expiratory record with the mixed expired R line (RE) ives the mean alveolar values (PAo2 and PAco2. 2)pa'co2 was calculated with the Bohr equation using a predicted anatomic dead space and PA'o2 was derived with the alveolar equation. 3) End-tidal (ET) P02 were averaged over 1 min at rest in steady state. Mean RET calculated from 3 was identical with RE. Mean values for PAco2, PA'CO2. and PETco2 differed by less that 1 Torr, but the variance was least with the end-tidal method. There was a highly significant correlation between delta aAPco2 using PETco2 and VD/VT, better than with either of the other methods. The end-tidal measurement appears to give the best approximation of mean alveolar gas in pulmonary patients.

Carbon Dioxide↗
PubMed1982

A prediction-correction scheme for forcing alveolar gases along certain time courses.

A computerized prediction-correction scheme has been devised for the control of alveolar gases. First, a model is run off-line to predict the inspiratory gas tensions at each second that should yield the desired alveolar patterns. Second, during the experiment, there is feedback correction based on the deviation of the actual alveolar values from the desired alveolar values. The actual alveolar values are found by a second computer and passed to the controlling computer using interrupts. The controlling computer has four digital-toi-analog outputs for controlling CO2, O2, N2, and air flows so as to achieve the commanded inspiratory PCO2 and PO2 (CO2 and O2 partial pressures, respectively). The scheme is illustrated for the generation of sinusoidal alveolar PCO2 with alveolar PO2 held constant and for steps of alveolar PCO2 at constant alveolar PO2.

Carbon Dioxide↗
PubMed1983

Exercise responses in pregnant sheep: blood gases, temperatures, and fetal cardiovascular system.

In an effort to examine the effects of maternal exercise on the fetus we measured maternal and fetal temperatures and blood gases and calculated uterine O2 consumption in response to three different treadmill exercise regimens in 12 chronically catheterized near-term sheep. We also measured fetal catecholamine concentrations, heart rate, blood pressure, cardiac output, blood flow distribution, blood volume, and placental diffusing capacity. Maternal and fetal temperatures increased a mean maximum of 1.5 +/- 0.5 (SE) and 1.3 +/- 0.1 degrees C, respectively. We corrected maternal and fetal blood gas values for the temperatures in vivo. Maternal arterial partial pressure of O2 (PO2), near exhaustion during prolonged (40 min) exercise at 70% maximal O2 consumption, increased 13% to a maximum of 116.7 +/- 4.0 Torr, whereas partial pressure of CO2 (PCO2) decreased by 28% to 27.6 +/- 2.2 Torr. Fetal arterial PO2 decreased 11% to a minimum of 23.2 +/- 1.6 Torr, O2 content by 26% to 4.3 +/- 0.6 ml X dl -1, PCO2 by 8% to 49.6 +/- 3.2 Torr, but pH did not change significantly. Recovery was virtually complete within 20 min. During exercise total uterine O2 consumption was maintained despite the reduction in uterine blood flow because of hemoconcentration and increased O2 extraction. The decrease of 3 Torr in fetal arterial PO2 and 1.5 ml X dl -1 in O2 content did not result in major cardiovascular changes or catecholamine release. These findings suggest that maternal exercise does not represent a major stressful or hypoxic event to the fetus.

Animals↗
PubMed1984

Measurement of hormones and blood gases during hypoxia in conscious cannulated rats.

Simple inexpensive methods are described for implanting chronic arterial cannulas for remote stress-free blood sampling of conscious unrestrained rats and for delivering acute isocapnic hypoxia to these rats in their home cages. The day before experimentation cages were placed in plastic bags with air (21% O2) flowing through at 15 1/min (normoxia). The next morning either normoxia was continued or isocapnic hypoxia (arterial PO2 38 Torr, arterial PCO2 38 Torr) was administered without handling or disturbing the rats. Repeated arterial samples were collected for measurement of blood gases, hematocrit, corticosterone, and ACTH. Blood pressure increased transiently (by 10 mmHg at 10 min) and plasma corticosterone and ACTH levels increased fivefold; hematocrit and heart rate did not change significantly. In rats receiving normoxia, all of these variables remained low. This preparation is useful for studying in conscious rats the regulation of endocrine systems easily stimulated by handling and for studying endocrine and cardiovascular adaptations to environmental stimuli such as hypoxia.

Acid-Base Equilibrium↗
PubMed1986

Arterial blood gases and acid-base status of dogs during graded dynamic exercise.

The objective of this study was to determine whether arterial PCO2 (PaCO2) decreases or remains unchanged from resting levels during mild to moderate steady-state exercise in the dog. To accomplish this, O2 consumption (VO2) arterial blood gases and acid-base status, arterial lactate concentration ([LA-]a), and rectal temperature (Tr) were measured in 27 chronically instrumented dogs at rest, during different levels of submaximal exercise, and during maximal exercise on a motor-driven treadmill. During mild exercise [35% of maximal O2 consumption (VO2 max)], PaCO2 decreased 5.3 +/- 0.4 Torr and resulted in a respiratory alkalosis (delta pHa = +0.029 +/- 0.005). Arterial PO2 (PaO2) increased 5.9 +/- 1.5 Torr and Tr increased 0.5 +/- 0.1 degree C. As the exercise levels progressed from mild to moderate exercise (64% of VO2 max) the magnitude of the hypocapnia and the resultant respiratory alkalosis remained unchanged as PaCO2 remained 5.9 +/- 0.7 Torr below and delta pHa remained 0.029 +/- 0.008 above resting values. When the exercise work rate was increased to elicit VO2 max (96 +/- 2 ml X kg-1 X min-1) the amount of hypocapnia again remained unchanged from submaximal exercise levels and PaCO2 remained 6.0 +/- 0.6 Torr below resting values; however, this response occurred despite continued increases in Tr (delta Tr = 1.7 +/- 0.1 degree C), significant increases in [LA-]a (delta [LA-]a = 2.5 +/- 0.4), and a resultant metabolic acidosis (delta pHa = -0.031 +/- 0.011). The dog, like other nonhuman vertebrates, responded to mild and moderate steady-state exercise with a significant hyperventilation and respiratory alkalosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1987

Catheter position and blood gases during constant-flow ventilation.

We studied the effect of catheter position and flow rate on gas exchange during constant-flow ventilation (CFV) in eight anesthetized, paralyzed dogs. The distal tips of the insufflation catheters were positioned 0.5, 2.0, 3.5, and 5.0 cm from the tracheal carina. Flow rates were varied between 10 and 55 l/min and steady-state arterial blood gases were measured. At a given flow rate, arterial CO2 pressure (PaCO2) decreased as CFV was administered further into the lung up to a distance of 3.5 cm from the carina; there were no significant differences in PaCO2 at 3.5 and 5.0 cm. For a given catheter position, PaCO2 decreased with increasing flow rate up to a flow rate of 40 l/min. Further increases in flow rate had no significant effect on PaCO2. Arterial O2 pressure (PaO2) was relatively constant at all flow rates and catheter positions. We conclude that, up to a point, CO2 elimination can be improved by positioning the catheters further into the lung; advancing the catheters further than 3.5 cm from the carina may cause over-ventilation of specific lung regions resulting in a relative plateau in CO2 elimination and relatively constant PaO2's. Positioning the catheters further into the lung permits the use of lower flow rates, thus potentially minimizing the risk of barotrauma.

Animals↗
PubMed1990

Tracheal blood flow during spontaneous and mechanical ventilation of dry gases in sheep.

Tracheal blood flow increases greater than twofold in response to eucapnic hyperventilation of dry gas in anesthetized sheep. To determine whether this occurs at normal minute ventilation, we studied sheep in which tracheal blood flow was measured in response to humid and dry gas ventilation while 1) awake and spontaneously breathing and 2) anesthetized and intubated during isocapnic mechanical ventilation. In additional sheep, three tracheal mucosal temperatures were measured during humid and dry gas mechanical ventilation to measure airway tissue cooling. Tracheal blood flow was determined by use of a left atrial injection of 15-microns-diam radiolabeled microspheres. Previously implanted flow probes on the pulmonary artery and the common bronchial artery allowed continuous recording of cardiac output and bronchial blood flow. Tracheal blood flow in awake spontaneously breathing sheep was 10.8 +/- 5.6 (SD) ml.min-1.100 g wet wt-1 while humid gas was breathed, and it was unchanged with dry gas. In contrast, isocapnic ventilation of intubated animals with dry gas resulted in a 10-fold increase in blood flow to the most proximal two-ring tracheal segment compared with that seen while humid gases were spontaneously ventilated [101 +/- 75 vs. 11 +/- 6 (SD) ml.min-1.100 g-1, P less than 0.05]. Despite a 10-fold increase in proximal tracheal blood flow, there was no response in distal tracheal and bronchial blood flow, as indicated by no change in the common bronchial artery blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1993

Breathing, transcutaneous blood gases, and CO2 response in SIDS siblings and control infants during sleep.

Age-related changes of 20 variables describing breathing patterns, transcutaneous blood gases, and estimated CO2 response during sleep were examined in a cross-sectional study of 30 healthy control infants and 150 healthy siblings of sudden infant death syndrome victims within the first 18 mo of life. Whole-night measurements were performed using noninvasive respiratory induction plethysmography and transcutaneous blood gas electrodes. Each candidate for the study was extensively screened and found to be healthy. Mean transcutaneous PCO2 (PtcCO2, median 40.3 Torr) and maximum PtcCO2 (median 44.8 Torr), as well as the estimated ventilatory response to inhalation of 2% CO2 in air during regular breathing, causing a 20-36% increase of ventilation per Torr PtcCO2, were not related to postnatal age. In contrast, paradoxical breathing decreased from 49.5 to 0% of total sleep time (TST), periodic breathing from 5.5 to 0% TST, and respiratory rate during regular breathing from 40 to 22 breaths/min; the portion of regular breathing increased from 32 to 55% TST and mean and minimum transcutaneous PO2 from 65.4 and 47 to 69.7 and 52 Torr with increasing stability. The largest changes occurred in the first 6 mo of life. Maximum apnea duration (9.5 s, maximum 16 s), mean apnea duration (3.74 s, breathing pauses > or = 2 s), and time spent apneic per hour of irregular breathing (199 s/h) were not related to age. The comparison of data from siblings and controls showed similarities in the above-mentioned variables. No significant differences were found among the groups. Also a comparison of 30 pairs of siblings and controls, matched for age, gender, birth, and actual body weight, did not show significant differences. The present study extends the knowledge of development of breathing control beyond the first 6 mo of life.

Aging↗
PubMed1993

Effects of pH and SO2 on solubility coefficients of inert gases in human whole blood.

We systematically investigated the quantitative importance of pH and O2 saturation (SO2) of hemoglobin on the solubility coefficients (alpha) for six inert gases: sulfur hexafluoride, N2, ethane, cyclopropane, halothane, and diethyl ether. Measurements of alpha were made at 37 degrees C with SO2 of 0-1.0 and pH of 7.2-7.7 by use of whole blood obtained from three healthy subjects. No significant dependence of alpha on pH was demonstrated for sulfur hexafluoride, N2, halothane, or diethyl ether, but an appreciable augmentation of alpha with increasing pH was found for ethane and cyclopropane. No alpha value obtained for oxygenated blood differed statistically from that for deoxygenated blood. In addition to the basic findings on the effects of pH on alpha values of ethane and cyclopropane with the multiple inert gas elimination technique (data obtained from 22 patients with either interstitial pneumonia or chronic obstructive pulmonary disease), we also found that dependence of alpha on blood pH exerted no significant influence on the recovery of ventilation-perfusion distribution in the lung. We concluded that: 1) pH plays an appreciable role in determining gas solubilities in blood, 2) SO2 is not a decisive factor for gas solubilities in blood, and 3) the influence of various pH values in pulmonary capillaries on inert gas exchange is negligible.

Adult↗
PubMed1994

Effect of arterial blood pressure and ventilation gases on cardiac depression induced by coronary air embolism.

In this study the time course of cardiac depression after selective intracoronary injection of air bubbles was investigated in six anesthetized pigs (30 +/- 2 kg) with different mixtures of ventilation gases and different mean arterial blood pressures (MAP). Air bubbles of 150 microns diam were injected into the left anterior descending coronary artery (LADCA) in a volume of 2 microliters/kg body wt. In each animal an injection of air bubbles was applied during ventilation with N2-O2 and a MAP of 77 +/- 3 mmHg (N2-O2/low pressure) or 111 +/- 3 mmHg (N2-O2/high pressure) and during ventilation with pure O2 and a MAP of 77 +/- 3 mmHg (O2/low pressure) or 110 +/- 3 mmHg (O2/high pressure). Systemic hemodynamic variables such as left ventricular pressure, its peak first derivatives, and MAP changed < 10% after injection of air bubbles. During N2-O2/low pressure, systolic segment length shortening in the LADCA region (SS-LADCA) decreased from baseline and did not return to baseline within the 10 min after injection of air bubbles. During N2-O2/high pressure and O2/low pressure, SS-LADCA was decreased between 60 and 120 s, whereas for O2/high pressure this period was from 60 to 90 s. By calculating the time integral of the deviation from baseline of SS-LADCA, it could be demonstrated that the depression of regional myocardial function was less severe during O2/high pressure and O2/low pressure than during N2-O2/low pressure. We conclude that, when coronary air embolism occurs during hypertension and during ventilation with pure O2 instead of a normal N2-O2 mixture, the resulting depression of regional myocardial function is reduced.

Animals↗
PubMed2000

Influence of positive end-expiratory pressure ventilation on peripheral tissue perfusion evaluated by measurements of tissue gases and pH. An experimental study in pigs with oleic acid lung injury. .

UNLABELLED: Measurements of subcutaneous oxygen tension (PscO(2)), subcutaneous carbon dioxide tension (PscCO(2)) and subcutaneous pH (pHsc) were used for evaluation of peripheral oxygenation in pigs subjected to oleic acid-induced lung injury during ventilation with increasing levels of positive end-expiratory pressure (PEEP). Lung injury resulted in a decrease of arterial oxygen tension (PaO(2)) from 93 to 37 mm Hg (p<0.01) with maintained cardiac output. PscO(2) decreased from 45 to 17 mm Hg (p<0.01) and pHsc from 7.47 to 7.39 (p<0.05), and PscCO(2) increased from 46 to 59 mm Hg (p<0.05). Increase of PEEP level between 5 and 20 cm H(2)O resulted in a continuous increase of PaO(2) from 45 to 145 mm Hg and a decrease of cardiac output from 4.1 to 2.0 liters/min (p<0.01). PscO(2) increased up to a PEEP level of 15 cm H(2)O, reaching 26 mm Hg. Further increase of PEEP level up to 20 cm H(2)O resulted in an increase of PscCO(2) from 65 to 71 mm Hg (p<0.05) and a decrease of pHsc from 7.31 to 7.29 (p<0.05). IN CONCLUSION: measurements of tissue gases and pH can be used to evaluate optimum peripheral tissue oxygenation during titration of PEEP level. Whether these measurements can be used as the only indicator to guide therapy in an individual case remains to be studied.

Animals↗
PubMed1999

Blood gases and sex hormones in women with and without genital descensus.

BACKGROUND: Abnormalities in connective tissue and spirometric disorders have previously been found in women with genital descensus. OBJECTIVE: To evaluate the association of descensus and respiratory function. METHODS: The blood gases and sex hormones were measured in 130 women scheduled for surgical correction of descensus and 60 matched women without descensus. All subjects were nonsmokers and without past or present cardiorespiratory disease. RESULTS: Women with descensus had a lower pH (7.39+/-0.04 vs. 7.41+/-0.04, p = 0.01), lower arterial tensions of oxygen (12.7+/-12. vs. 14.1+/-0.9 kPa, p = 0.003) and carbon dioxide (5.1+/-0.4 vs. 5.3+/-0.3 kPa) but a higher hemoglobin concentration (141+/-11 vs. 132+/-9 g/l) and a higher serum progesterone in the follicular phase of the cycle (3.1+/-4 vs. 1.5+/-1 ng/ml, p = 0.03). In 39 (30%) women with descensus, the arterial carbon dioxide tension was below 4.9 kPa. All subjects ventilated more in the luteal compared to the follicular phase of the cycle. In women with descensus, the hemoglobin concentration increased with decreasing arterial oxygen tension (p = 10(-4)) and with decreasing pH (p<10(-3)). CONCLUSION: Women with descensus frequently hyperventilate and, compared with women without descensus, have a lower arterial oxygen tension, increased hemoglobin concentration and slightly lower pH.

Carbon Dioxide↗
PubMed2000

Continuous monitoring of arterial blood gases and pH during intraoperative rapid blood administration using a Paratrend sensor.

BACKGROUND AND OBJECTIVES: The aim of this study was to determine the effects of rapid transfusion of packed red cells on the arterial blood gases and acid-base status of the recipient. MATERIALS AND METHODS: We studied 16 patients (mean age 66.3+/-9.9 years) who received rapid transfusion of 632.8+/-287.2 g of packed red cells in CPDA-1, stored before use for a period of 15.2+/-4.4 days. During transfusion, monitoring of pH, PCO2 and PO2 was continuous using an intra-arterial multiparameter sensor (Paratrend 7, Biomedical Sensors, UK). RESULTS: The rate of the transfusion was 73.1+/-9.6 g/min and the duration of observation was 35.8+/-12.8 min. Arterial pH decreased from 7.446+/-0.023 to 7.385+/-0.034 (p<0.001) and PCO2 increased from 32.31+/-1.35 to 36.41+/-1.86 mmHg (p<0.001). Delta pH and delta PCO2 showed significant correlation to the weight and the age of the transfused blood (p<0.001 for both dependent variables). The rate of pH change was positively but insignificantly correlated to the rate of the transfusion. Base excess was significantly decreased and end-tidal CO2 (PetCO2) was increased from 25.8+/-2.0 to 28.1+/-2.3 mmHg (p<0.05), significantly correlating to the amount and age of the administered component (p<0.05). PetCO2 was not elevated when PCO2 changes were minimal. Alterations in PO2 were not specific and our clinical impression was that they were related to unmeasured parameters. CONCLUSION: Our findings suggest that the fall in pH and the elevation in PCO2 which occur during rapid transfusion of packed red cells may go undetected or be misinterpreted if the acid-base status of the recipient is not monitored continuously. These alterations are mainly of metabolic character and depend on the amount and age of the transfused component. Our data suggest that arterial sampling is essential during massive transfusions.

Aged↗
PubMedDate not supplied

Effects of almitrine bismesylate on arterial blood gases in patients with chronic obstructive pulmonary disease and moderate hypoxaemia: a multicentre, randomised, double-blind, placebo-controlled study.

BACKGROUND: Advanced chronic obstructive pulmonary disease (COPD) generates high costs, especially when patients require domiciliary long-term oxygen therapy (LTOT). Almitrine bismesylate has been shown to improve gas exchange in the lungs. Our hypothesis was that long-term treatment with almitrine might postpone the prescription of LTOT. OBJECTIVE: To evaluate the effects of almitrine sequential treatment on arterial blood gases in COPD patients with moderate hypoxaemia. METHODS: COPD patients with moderate hypoxaemia [partial oxygen tension in arterialised blood (PaO(2)) between 7.33 and 8.66 kPa (56-65 mm Hg)] were investigated. After a 1-month run-in period, patients were given either almitrine 100 mg per day or placebo for sequential treatment for a total of 12 months. RESULTS: 115 patients in a steady state (57 in the almitrine and 58 in the placebo group) were included. Mean age was 60 years, mean forced expiratory volume in 1 s was 34 +/- 13% of predicted and mean PaO(2) was 8.04 +/- 0.5 kPa (60.5 +/- 3.8 mm Hg). 38 patients were lost to follow-up, 23 in the almitrine and 15 in the placebo group. The majority of drop-outs were due to adverse events (AE; 16 in the almitrine and 9 in the placebo group). Almitrine treatment resulted in PaO(2) improvement of 0.43 +/- 0.88 kPa (3.2 +/- 6.6 mm Hg) (p = 0.003). The treatment effect between almitrine and placebo was 0.45 kPa (3.4 mm Hg) (p = 0.003). In the almitrine group, two distinct subgroups were observed: responders (n = 19) and non-responders (n = 38). Almitrine treatment in responders resulted in a clinically significant improvement in PaO(2) of 1.36 +/- 0.7 kPa (10.2 +/- 5.3 mm Hg) (p < 0.0001) and a reduction of partial carbon dioxide tension in arterialised blood. 31 patients experienced serious AE: 17 in the almitrine and 14 in the placebo group. Five patients died during the study (3 in the almitrine and 2 in the placebo group). Most AE occurring during the study were related to underlying disease. Clinical diagnosis of polyneuropathy resulted in the withdrawal of 5 patients in the almitrine group and 3 patients in the placebo group. Four patients in the almitrine group experienced weight loss. CONCLUSIONS: Almitrine treatment of patients with severe COPD and moderate hypoxaemia resulted in a small but significant improvement in PaO(2) over 12 months. A clinically important improvement in gas exchange was observed in 33% of treated patients. These patients may be candidates for long-term treatment.

Aged↗
PubMed1991

Morphological changes in human chorionic villi cultivated in conditioned atmospheres of gases.

With the aim to verify the changes that a reduction of the oxygen rate may elicit in the morphological pattern of the human chorionic villi, a new experimental procedure has been suggested. Chorionic villi from human early placentas were incubated in Dulbecco's modified medium of Eagle in the presence of oxygen, air or CO2 at a gas pressure equal to 0.7 atm. The specimens were fixed, dehydrated and embedded in resin, and semithin sections were obtained. Using an image analyser, the thickness of the trophoblastic layer and the mean radius of the villi were evaluated and the results submitted to a statistical analysis. The results show a decrease in the ratio thickness of the trophoblast/mean radius of the villus, directly proportional to the reduction of the oxygen percentage in the employed gases. The interesting conclusions demonstrate that the changes which affect the chorionic villi occur very early and are easily evaluable with quantitative methods; a clinical interest in the use of the proposed quantitative procedure can be emphasized.

Air↗