Changes in acid-base status in oxygen toxicity at 230 kPa oxygen as a function of exposure time

2021 ◽  
pp. 239-245
Author(s):  
Xiao-Chen Bao ◽  
◽  
Hong Chen ◽  
Yi-Qun Fang ◽  
Nang Wang ◽  
...  

Breathing less than 50 kPa of oxygen over time can lead to pulmonary oxygen toxicity (POT). Vital capacity (VC) as the sole parameter for POT has its limitations. In this study we try to find out the changes of acid-base status in a POT rat model. Fifty male rats were randomly divided into five groups, exposed to 230 kPa oxygen for three, six, nine and 12 hours, respectively. Rats exposed to air were used as controls. After exposure the mortality and behavior of rats were observed. Arterial blood samples were collected for acid-base status detection and wet-dry (W/D) ratios of lung tissues were tested. Results showed that the acid-base status in rats exposed to 230 kPa oxygen presented a dynamic change. The primary status was in the compensatory period when primary respiratory acidosis was mixed with compensated metabolic alkalosis. Then the status changed to decompensated alkalosis and developed to decompensated acidosis in the end. pH, PCO2, HCO3-, TCO2, and BE values had two phases: an increase and a later decrease with increasing oxygen exposure time, while PaO2 and lung W/D ratio showed continuously increasing trends with the extension of oxygen exposure time. Lung W/D ratio was significantly associated with PaO2 (r = 0.6385, p = 0.002), while other parameters did not show a significant correlation. It is concluded that acid-base status in POT rats presents a dynamic change: in the compensatory period first, then turns to decompensated alkalosis and ends up with decompensated acidosis status. Blood gas analysis is a useful method to monitor the development of POT.

1989 ◽  
Vol 66 (6) ◽  
pp. 2895-2900 ◽  
Author(s):  
T. I. Musch ◽  
B. S. Warfel ◽  
R. L. Moore ◽  
D. R. Larach

We compared the effects of three different anesthetics (halothane, ketamine-xylazine, and diethyl ether) on arterial blood gases, acid-base status, and tissue glycogen concentrations in rats subjected to 20 min of rest or treadmill exercise (10% grade, 28 m/min). Results demonstrated that exercise produced significant increases in arterial lactate concentrations along with reductions in arterial Pco2 (PaCO2) and bicarbonate concentrations in all rats compared with resting values. Furthermore, exercise produced significant reductions in the glycogen concentrations in the liver and soleus and plantaris muscles, whereas the glycogen concentrations found in the diaphragm and white gastrocnemius muscles were similar to those found at rest. Rats that received halothane and ketamine-xylazine anesthesia demonstrated an increase in Paco2 and a respiratory acidosis compared with rats that received either anesthesia. These differences in arterial blood gases and acid-base status did not appear to have any effect on tissue glycogen concentrations, because the glycogen contents found in liver and different skeletal muscles were similar to one another cross all three anesthetic groups. These data suggest that even though halothane and ketamine-xylazine anesthesia will produce a significant amount of ventilatory depression in the rat, both anesthetics may be used in studies where changes in tissue glycogen concentrations are being measured and where adequate general anesthesia is required.


PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255829
Author(s):  
Leander Gaarde ◽  
Stefanie Kolstrup ◽  
Peter Bollen

In anaesthetic practice the risk of hypoxia and arterial blood gas disturbances is evident, as most anaesthetic regimens depress the respiratory function. Hypoxia may be extended during recovery, and for this reason we wished to investigate if oxygen supply during a one hour post-operative period reduced the development of hypoxia and respiratory acidosis in rats anaesthetized with fentanyl/fluanisone and midazolam. Twelve Sprague Dawley rats underwent surgery and were divided in two groups, breathing either 100% oxygen or atmospheric air during a post-operative period. The peripheral blood oxygen saturation and arterial acid-base status were analyzed for differences between the two groups. We found that oxygen supply after surgery prevented hypoxia but did not result in a significant difference in the blood acid-base status. All rats developed respiratory acidosis, which could not be reversed by supplemental oxygen supply. We concluded that oxygen supply improved oxygen saturation and avoided hypoxia but did not have an influence on the acid-base status.


1996 ◽  
Vol 199 (4) ◽  
pp. 933-940
Author(s):  
B Tufts ◽  
S Currie ◽  
J Kieffer

In vivo experiments were carried out to determine the relative effects of carbonic anhydrase (CA) infusion or inhibition on carbon dioxide (CO2) transport and acid-base status in the arterial and venous blood of sea lampreys recovering from exhaustive exercise. Infusion of CA into the extracellular fluid did not significantly affect CO2 transport or acid-base status in exercised lampreys. In contrast, infusion of the CA inhibitor acetazolamide resulted in a respiratory acidosis in the blood of recovering lampreys. In acetazolamide-treated lampreys, the post-exercise extracellular pH (pHe) of arterial blood was significantly lower than that in the saline-infused (control) lampreys. The calculated arterial and venous partial pressure of carbon dioxide (PCO2) and the total CO2 concentration in whole blood (CCO2wb) and red blood cells (CCO2rbc) during recovery in the acetazolamide-infused lampreys were also significantly greater than those values in the saline-infused control lampreys. These results suggest that the CO2 reactions in the extracellular compartment of lampreys may already be in equilibrium and that the access of plasma bicarbonate to CA is probably not the sole factor limiting CO2 transport in these animals. Furthermore, endogenous red blood cell CA clearly has an important role in CO2 transport in exercising lampreys.


1979 ◽  
Vol 82 (1) ◽  
pp. 345-355
Author(s):  
R. G. BOUTILIER ◽  
D. J. RANDALL ◽  
G. SHELTON ◽  
D. P. TOEWS

Cutaneous CO2 excretion is reduced as the skin dries during dehydration but an increase in breath frequency acts to regulate the arterial blood Pcoco2 and thus pHα. Moreover, the toad does not urinate and water is reabsorbed from the bladder to replace that lost by evaporation at the skin and lung surfaces. The animal does, however, produce a very acid bladder urine to conserve circulating levels of plasma [HCO3-] and this together with an increased ventilation effectively maintains the blood acid-base status for up to 48 h of dehydration in air. Water loss and acid production are presumably also reduced by the animal's behaviour; animals remain still, in a crouched position or in a pile if left in groups. Dehydrated toads are less able than hydrated toads to regulate blood pH during hypercapnia: they hyperventilate and mobilize body bicarbonate stores in much the same fashion as hydrated animals but due to the restrictions on cutaneous CO2 excretion and renal output, there is comparatively little reduction in the PCOCO2 difference between arterial blood and inspired gas thereby resulting in a more severe respiratory acidosis. These factors further contribute to the persistent acidosis which continues even when the animals are returned to air.


2017 ◽  
Vol 5 (3) ◽  
pp. 11-17
Author(s):  
S Adhikari ◽  
S K Shrestha ◽  
B Srivastava ◽  
N B KC ◽  
B B Singh ◽  
...  

Arterial blood gas (ABG) sampling is an essential investigation for assessment of acid-base status, oxygenation and ventilation in critical care practice. Arterial puncture to obtain arterial blood is more invasive procedure than venous and has more potential complications. To find out the correlation between arterial and peripheral venous blood gas values for pH, PCO2 and bicarbonate. Patients admitted in ICU requiring arterial blood gas analysis to determine their acid-base status or ventilatory status was included in the study. One milliliter of venous blood was obtained in a heparin flushed syringe within 5 minutes of getting arterial blood sample. Both labeled samples were processed immediately. Data were analyzed by student’s t-test. A total of 50 paired samples from 36 patients were evaluated. The mean differences between arterial and venous blood gas values for pH, PCO2 and bicarbonate were 0.02 units, -2.37 mmHg and -0.45 mEq/L respectively. Similarly, the correlation coefficients between arterial and venous parameters were 0.964, 0.881 and 0.906 for pH, PCO2 and bicarbonate respectively, which were statistically significant (p<0.001). Venous pH, PCO2 and bicarbonate showed a very high level of correlation with the respective arterial values.


2018 ◽  
Vol 59 (4) ◽  
pp. 149-155
Author(s):  
Kristina Galić ◽  
Danijel Pravdić ◽  
Zrinko Prskalo ◽  
Suzana Kukulj ◽  
Boris Starčević ◽  
...  

2007 ◽  
Vol 47 (1) ◽  
pp. 35
Author(s):  
Hari Kushartono ◽  
Antonius H. Pudjiadi ◽  
Susetyo Harry Purwanto ◽  
Imral Chair ◽  
Darlan Darwis ◽  
...  

Background Base excess is a single variable used to quantifymetabolic component of acid base status. Several researches havecombined the traditional base excess method with the Stewartmethod for acid base physiology called as Fencl-Stewart method.Objective The purpose of the study was to compare two differentmethods in identifying hyperlactacemia in pediatric patients withcritical illness.Methods The study was performed on 43 patients admitted tothe pediatric intensive care unit of Cipto MangunkusumoHospital, Jakarta. Sodium, potassium, chloride, albumin, lactateand arterial blood gases were measured. All samples were takenfrom artery of all patients. Lactate level of >2 mEq/L was definedas abnormal. Standard base excess (SBE) was calculated fromthe standard bicarbonate derived from Henderson-Hasselbalchequation and reported on the blood gas analyzer. Base excessunmeasured anions (BE UA ) was calculated using the Fencl-Stewartmethod simplified by Story (2003). Correlation between lactatelevels in traditional and Fencl-Stewart methods were measuredby Pearson’s correlation coefficient .Results Elevated lactate levels were found in 24 (55.8%) patients.Lactate levels was more strongly correlated with BE UA (r = - 0.742,P<0.01) than with SBE (r = - 0.516, P<0.01).Conclusion Fencl-Stewart method is better than traditionalmethod in identifying patients with elevated lactate levels, so theFencl-Stewart method is suggested to use in clinical practice.


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