Blood Acid-base Status Research Articles

Urine pH as predictor of blood acid-base status in dairy cattle fed acidogenic diets

We determined the association between urine pH and blood acid-base indicators and assessed a urine pH cut-off value to predict severe metabolic acidosis under field conditions in cows fed acidogenic diets. Eighty-six cows were sampled for urine and blood. Urine pH was evaluated immediately after collection, and blood acid-base status was evaluated within 2 hours of collection using a portable blood analyzer. Twenty-five cows were classified as having severe metabolic acidosis (blood pH ≤ 7.4; bicarbonate < 24 mmol/L, base excess ≤ −0.5; PCO2 low to normal concentrations and urine pH between 4.88 and 5.71. There was a positive linear association between urine pH and blood pH (r = 0.46), and between urine pH and base excess (r = 0.74). The area under the ROC curve was 0.91 (CI 95 %= 0.84–0.96; good-excellent test). The optimal cut-off value for urine pH to categorize a cow with severe metabolic acidosis was 5.5 (94 % specificity and 72 % sensitivity). For each 0.1 unit of decrease in urine pH below 5.5, cows were 1.6 times (95 % CI= 1.3–2.1) more likely to exhibit a severe metabolic acidosis. We conclude that a urine pH of 5.5 or less is indicative of more life-threatening metabolic acidosis in dairy cows.

Pre-clinical evaluation of effectiveness of infusion solutions with different osmolarity during acute blood loss in experiments on rats

The aim of the research was to experimentally evaluate the effectiveness of infusion solutions with different osmolarity during acute blood loss in experiments on rats. Material and methods. Experiments approved by the local Ethics Committee, have been done on 30 male rats line Vistar (320 ± 35 g). Design of the research included anesthesia, simulation of acute blood loss to 50 % of circulating blood volume, its replenishment with experimental infusion solutions based on polyglycan derivatives (estimated osmolarity 1026.6, 1784.2, 2566.6 mOsm/l), research of survivability, functional state of cardiovascular and respiratory systems, blood acid-base status and gas partial pressure 5, 30, 60, 120, 180 min after the beginning of replenishment of circulating blood volume. The infusion solution Hemostabil was used as a comparison product. Results. The highest survival rate, restoration of hemodynamics and acid-base state and blood acid-base status and gas partial pressure were obtained as a result of infusion of solution with osmolarity 1026.6 mOsm/l. In this group of animals survivability accounted for 100 %, arterial pressure restored in 5 minutes after the start of infusion, indicators of blood acid-base status and gas partial pressure normalized in 120 min of experiment. All of the results had statistically significant differences (p &lt; 0.05) relative to values in other experimental groups. Conclusions. Sample of solution with osmolarity 1026.6 mOsm/l is the most effective in restoration of hemodynamics of rats with the blood loss up to 50 % of circulating blood volume. The expediency of the researches of safety of this infusion solution based on polyglucan derivatives in the capacity of medication for replenishment acute blood loss is substantiated.

Asphyxial Circulatory Arrest with a Complex of Resuscitation Measures in an Experimental Model

The majority of asphyxial circulatory arrest (CA) models have a number of disadvantages, such as the lack of uniform criteria for fixing CA and recovery of spontaneous circulation, short duration of CA episode and limited volume of post-resuscitation intensive care, poor similarity with resuscitation measures in current clinical anesthesiology/intensive care settings.The aim of the study: to improve the experimental model of asphyxicial CA by standardizing experimental procedures and using a complex of resuscitation measures replicating current CA management in clinical anesthesiology-intensive care.Materials and methods. The experiments were conducted on 34 male Wistar rats, distributed into 2 groups: Group I included animals subjected to sham procedure (SP, N=12) and Group II – animals subjected to asphyxial circulatory arrest (CA, N=22) and subsequent resuscitation. Asphyxia in anesthetized rats was induced by rocuronium bromide injection, followed by recording of electrocardiogram (ECG), parameters of invasive blood pressure (BP) measurement and laser Doppler fluxmetry (LDF) to assess skin perfusion. CA episode was maintained for 2 min, followed by a series of resuscitation measures and intensive therapy for 2 h. Circulatory parameters (ECG, BP, LDF), gas composition and arterial blood acid-base state (ABS) dynamics were evaluated.Results. Monitored parameters were comparable in both groups at baseline after stabilization period. After exclusion criteria were applied 11 animals from SP group and 18 — from CA were included in the analysis. Tachycardia (heart rate, beats/min–1, SP vs CA) was documented in the CA group: 218 [205; 236] vs 286 [272; 305], P⩽0.0001), as well as recovery of skin perfusion to subnormal parameters in the first minutes after successful resuscitation. At minute 10 in the post-resuscitation period worsening of skin perfusion (M, perfusion units, SP vs CA): 14.7 [12.1; 16.5] vs 10.1 [7.0; 12.5], P=0.0014), and decompensated mixed acidosis (pH, SP vs CA): 7.42 [7.40; 7.43] vs 7.20 [7.13; 7.23], P⩽0.0001) were documented in the CA group, however BP values were comparable (BP, mmHg, SP vs CA): 60 [58; 72] vs 67 [62; 82], P=0.482). At minute 120 post-resuscitation and at the end of intensive care period, both groups demonstrated similar values of the monitored parameters. Three out of 18 animals in the CA group died after resuscitation.Conclusion. Electromechanical dissociation underlies CA in rats subjected to asphyxia. The use of LDF to assess peripheral blood flow makes it possible to standardize the severity of ischemic reperfusion injuries and improve reproducibility of the model. Series of resuscitation measures in experimental setting is justified from a bioethical point of view, and makes it possible to improve repeatability of preclinical research results in clinical practice.

СОСТОЯНИЕ ФУНКЦИИ ВНЕШНЕГО ДЫХАНИЯ И ГАЗОВОГО СОСТАВА КРОВИ У ДЕТЕЙ С НАСЛЕДСТВЕННЫМИ ГЕМОЛИТИЧЕСКИМИ АНЕМИЯМИ

Objective: Investigation of the connection between the changes of the blood gas composition and external respiration (ER) disorders in children with hereditary hemolytic anemia (HHA) Methods: Forty-eight children with HHA hospitalized in the Pediatric Hematology Department of the National Medical Center of the Republic of Tajikistan “Shifobakhsh” (NMCRT) were examined. The patients were divided into three groups based on the severity of anemia: group 1 – 18 (37.5%) children with mild HHA, group 2 – 20 (41.7%) children with moderate HHA and group 3 – 10 (20.8%) children with severe HHA. The control group included 20 healthy children of comparable age and gender distribution. All patients with HHA underwent blood gas analysis and ER tests Results: There was no significant difference the blood acid-base status (ABS) between the children of the control and mild HHA groups: (pH – 7.36 [7.35; 7.36], pCO2 – 36.0 [35.3; 37.1], HCO3 - −24.8 [23.9; 24.5]) vs. (pH – 7.35 [7.35; 7.37], pCO2 – 39.4 [37.4; 40.6], HCO3 - − 22.8 [22.1; 23.6]) respectively. These parameters in children with moderate and severe HHA (pH – 7.32 [7.31; 7.33], pCO2 – 42.6 [41.8; 46.0], HCO3 - − 17.3 [17.0; 17.7]) and (pH – 7.28 [7.27; 7.29], pCO2 – 51.3 [50.3; 51.7], HCO3 - − 15.5 [14.8; 16.3]) respectively, were significantly different from the control group. Spirographic parameters in patients with moderate (Forced Expiratory Volume (FEV1 ) – 79.5 [79.5; 81.0], Tiffeneau index (TI) – 75.7 [74.9; 77.3], Forced Vital Capacity (FVC) – 78.4 [77.8; 80.6])} and severe anemia (FEV1 – 67.6 [66.8; 68.2], IT – 83.0 [83.8; 84.6], FVC – 66.0 [65.8; 68.2]) were significantly different from those with mild anemia (FEV1 – 82.3 [81.7; 83.8], TI – 75.8 [74.9; 76.8], FVC – 85.3 [84.2; 85.6]) and the control group (FEV1 – 86.9 [85.5; 88.3], IT – 75.2 [74.8; 75.9], FVC – 85.4 [84.5; 86.3]) Conclusion: The results of the study revealed pronounced changes in blood ABS and pulmonary ventilation disorder in children with a severe form of HHA Keywords: Hereditary hemolytic anemia, external respiration, hypoxia, acidosis.

Conventional Feed-Grade or Slow-Release Coated Urea as Sources of Dietary Nitrogen for Fattening Lambs.

Twenty-two Assaf male lambs (29.2 ± 0.9 kg live weight and 89 ± 0.2 days of age), distributed in two experimental groups, were used to evaluate the use of either feed-grade conventional urea (Control diet; n = 11) or slow-release urea (SRU diet; n = 11) as sources of dietary nitrogen on animal performance, ruminal fermentation, blood acid-base status, plasmatic metabolic profile, and carcass and meat quality. Animals were housed individually and fed ad libitum. At the end of the fattening period (day 70), the animals were slaughtered to compare the fermentation patterns in ruminal digesta and to evaluate the carcass and meat characteristics. No statistically significant differences (p > 0.05) were observed between treatments in the dry matter intake, final live weight, average daily gain, and feed conversion rate. Regarding the ruminal fermentation parameters, the molar proportion of propionic acid was higher (p < 0.05) and that of butyric acid was lower (p < 0.05) with the SRU than with the Control diet. There were no significant differences (p > 0.05) between experimental treatments in the blood acid-base status and biochemical profile, except for the concentration of urea in plasma, which was significantly (p < 0. 05) greater in SRU than in Control lambs. No statistically significant differences were observed between treatments (p > 0.05) in the carcass and meat characteristics. In conclusion, the use of slow-release urea as a replacement for feed-grade conventional urea in the diet of Assaf fattening lambs, under the experimental conditions of this study, did not improve animal performance and increased the feeding costs.

Physicochemical properties of abnormal blood acid-base buffering.

This paper describes two new features 1) development of physicochemically based, two-compartment models describing acid-base-state changes in normal and abnormal blood and 2) use of model results to view and describe physicochemical properties of blood, in terms of Pco2 as the causative independent variable and effected [H+] changes as the dependent variable. Models were derived from an in vitro experimental study, where normal blood was made both hypoproteinemic and hyperalbuminemic and then equilibrated with CO2. Strong-ion gap (SIG) values were selected to match model and experimental pH. The effect of individual physicochemical factors affecting blood acid-base-state were evaluated from their induced changes on buffer curve linearized slope (βH+) and [H+] curve shift at 40 mmHg ([H+]40). Model findings were: 1) in severe hypoproteinemia, hemoglobin enhances buffering (decreases βH+), whereas albumin compromises it, resulting in an almost unchanged βH+; [H+]40 decreases (alkalemia) due to hypoalbuminemia. 2) Severe hyperalbuminemia greatly increases both βH+ and [H+]40, hence, compromising buffering and causing a severe acidemia. 3) Pco2-induced changes in the electrical-charge concentration of hemoglobin are the principal factor responsible for maintaining normal buffering characteristics in hypoproteinemia and hyperalbuminemia. 4) SIG values are a third Pco2-independent characteristic of blood acid-base state and 5) the quantities, βH+, [H+]40, and SIG, derived from a [H+] vs. Pco2 perspective, are a more informative and intuitive way to characterize blood acid-base state.NEW & NOTEWORTHY This study represents the most up-to-date, physicochemical, multi-compartment computer model of the processes involved in determining the acid-base buffering state of blood. Previous models lack this capability, notably by being single compartment and/or lacking electroneutrality and osmotic constraints. Model results, analyzed from a different perspective of dependent [H+] changes resulting from independent Pco2 changes, provide a new set of Pco2-independent parameters, characteristic of blood buffering properties.

Non-carbonic buffer power of whole blood is increased in experimental metabolic acidosis: An in-vitro study.

Non-carbonic buffer power (βNC) of blood is a pivotal concept in acid-base physiology as it is employed in several acid-base evaluation techniques, including the Davenport nomogram and the Van Slyke equation used for Base excess estimation in blood. So far, βNC has been assumed to be independent of metabolic acid-base status of blood, despite theoretical rationale for the contrary. In the current study, we used CO2 tonometry to assess βNC in blood samples from 10 healthy volunteers, simultaneously analyzing the electrolyte shifts across the red blood cell membrane as these shifts translate the action of intracellular non-carbonic buffers to plasma. The βNC of the blood was re-evaluated after experimental induction of metabolic acidosis obtained by adding a moderate or high amount of either hydrochloric or lactic acid to the samples. Moreover, the impact of βNC and pCO2 on the Base excess of blood was examined. In the control samples, βNC was 28.0 ± 2.5mmol/L. In contrast to the traditional assumptions, our data showed that βNC rose by 0.36mmol/L for each 1 mEq/l reduction in plasma strong ion difference (p < 0.0001) and was independent of the acid used. This could serve as a protective mechanism that increases the resilience of blood to the combination of metabolic and respiratory acidosis. Sodium and chloride were the only electrolytes whose plasma concentration changed relevantly during CO2 titration. Although no significant difference was found between the electrolyte shifts in the two types of acidosis, we observed a slightly higher rate of chloride change in hyperchloremic acidosis, while the variation of sodium was more pronounced in lactic acidosis. Lastly, we found that the rise of βNC in metabolic acidosis did not induce a clinically relevant bias in the calculation of Base excess of blood and confirmed that the Base excess of blood was little affected by a wide range of pCO2.

Physicochemical Analysis of Mixed Venous and Arterial Blood Acid-Base State in Horses at Core Temperature during and after Moderate-Intensity Exercise.

Simple SummaryThe purposes of the present study were to determine the effect of core body temperature on acid-base variables and determine the origins of acid-base changes in the arterial and mixed venous blood of horses during exercise and recovery. Moderate intensity exercise resulted in an increase in body temperature that, in addition to exercise, affected acid-base status and gas partial pressures. Moderate intensity exercise resulted in a mild alkalosis that had markedly different origins in arterial blood than in mixed venous blood, and this was affected by the increase in core temperature during exercise and its resolution during recovery. In order to fully understand how acid-base status changes during exercise and recovery, it is importance to quantify the changes in both arterial and mixed venous blood, with adjustment to core temperature. Acid-base assessments using jugular vein blood samples are limited in comparison.The present study determined the independent contributions of temperature, strong ion difference ([SID]), total weak acid concentration ([Atot]) and PCO2 to changes in arterial and mixed venous [H+] and total carbon dioxide concentration ([TCO2]) during 37 min of moderate intensity exercise (~50% of heart rate max) and the first 60 min of recovery. Six horses were fitted with indwelling carotid and pulmonary artery (PA) catheters, had PA temperature measured, and had blood samples withdrawn for immediate analysis of plasma ion and gas concentrations. The increase in core temperature during exercise (+4.5 °C; p < 0.001) significantly (p < 0.05) increased PO2, PCO2, and [H+], but without a significant effect on [TCO2] (p > 0.01). The physicochemical acid-base approach was used to determine contributions of independent variables (except temperature) to the changes in [H+] and [TCO2]. In both arterial and venous blood, there was no acidosis during exercise and recovery despite significant (p < 0.05) increases in [lactate] and in venous PCO2. In arterial blood plasma, a mild alkalosis with exercise was due to primarily to a decrease in PCO2 (p < 0.05) and an increase in [SID] (p < 0.1). In venous blood plasma, a near absence of change in [H+] was due to the acidifying effects of increased PCO2 (p < 0.01) being offset by the alkalizing effects of increased [SID] (p < 0.05). The effect of temperature on PO2 (p < 0.001) resulted in an increased arterio-venous PO2 difference (p < 0.001) that would facilitate O2 transfer to contracting muscle. The simultaneous changes in the PCO2 and the concentrations of the other independent acid-base variables (contributions from individual strong and weak ions as manifest in [SID] and [Atot]) show complex, multilevel control of acid-base states in horses performing even moderate intensity exercise. Correction of acid-base variables to core body temperature presents a markedly different physiological response to exercise than that provided by variables measured and presented at an instrument temperature of 37 °C.

Mechanisms of Blood pH Changes in Venovenous Extracorporeal Membrane Systems: Roles of Hemoglobin-Ion Binding and Donnan Equilibrium.

An equilibrium model was developed to understand interrelated, physicochemical mechanisms leading to blood pH and electrolyte distribution changes in patients because of venovenous extracorporeal membrane oxygenation (ECMO) and carbon dioxide removal. The model consists of plasma and red cell compartments between which water and small ions can move to establish an equilibrium state. Governing forces are as follows: 1) ionic electroneutrality in each compartment; 2) osmotic equilibrium between compartments; 3) mass balance of small ions other than bicarbonate; 4) oxygen (O 2 )-dependent hemoglobin (Hb)-Cl binding in red cells; 5) albumin binding to Cl - , Ca 2+ , and Mg 2+ in plasma; and 6) chemical equilibria of carbonates and phosphates in each compartment. The model was constructed and validated using recent clinical ECMO inlet and exit blood-pH and electrolyte concentration data. The model closely described pH and electrolyte concentration changes in both states, which validated the model. The model was then used to predict CO 2 and O 2 saturation-induced changes in pH and electrolyte concentrations. It was found that O 2 -dependent Hb-Cl binding had a much lesser effect on blood acid-base status changes and electrolyte shifts during ECMO than previously thought. The model showed that the Cl-shift and Gibbs-Donnan equilibrium effects, characterized by pH and electrolyte distribution changes during ECMO, were primarily caused by changes in pH-induced electrical charge on mainly Hb and other constrained ions in red cells. These insights can improve understanding of the same factors acting when blood traverses the lung.

The Effect of the Non-compressed Oxygen Therapy and Hyperbaric Oxygenation in Combination With Standardized Drug Therapy on the Blood Acid-Base State Biomarkers in Alcohol Withdrawal Syndrome, an Experimental Study.

In alcohol withdrawal syndrome (AWS), pathophysiological mechanisms cover acid-base disturbances that affect the clinical picture of this state. An earlier study found that oxygen therapy methods in combination with pharmacotherapy improved the cognitive state in persons suffering from AWS. As impairments in the acid-base state influence the general health, timely and effective correction of these acid-base disturbances could result in a potential improvement in the treatment of the alcohol withdrawal symptoms. Therefore, the aim of this study was to evaluate the effectiveness of non-compressed oxygen therapy (NOT) and hyperbaric oxygenation (HBO) in combination with standard drug therapy (SDT), based on the dynamics of the acid-base state (ABS) in blood during AWS. HBO is the use of oxygen under pressure, whereas NOT uses oxygen without pressure. A comparative assessment of the acid-base state biomarkers was made in 160 patients with a moderate alcohol withdrawal state (3 groups), namely, in patients who underwent SDT only (control group/CG; n = 42) and two comparison groups who underwent SDT in combination with NOT (SG1 group; n = 56) and HBO (SG2 group; n = 62). The use of both oxygen therapy methods (i.e., NOT and HBO) in combination with SDT corrected the ABS in a shorter time and more effectively, which was due to the better restoration of the carbonate buffer system. Although we did not find proof that novel oxygen-related therapeutic procedures such as NOT and HBO in combination with SDT improved the alcohol withdrawal symptoms, it helped with the faster restoration of the acid-base state.

Norepinephrine versus phenylephrine infusion for preventing postspinal hypotension during cesarean section for twin pregnancy: a double-blinded randomized controlled clinical trial

BackgroundCompared with singleton pregnancy, twin gestation is featured by a greater increase in cardiac output. Therefore, norepinephrine might be more suitable than phenylephrine for maintaining blood pressure during cesarean section for twins, as phenylephrine causes reflex bradycardia and a resultant decrease in cardiac output. This study was to determine whether norepinephrine was superior to phenylephrine in maintaining maternal hemodynamics during cesarean section for twins.MethodsInformed consent was obtained from all the patients before enrollment. In this double-blinded, randomized clinical trial, 100 parturients with twin gestation undergoing cesarean section with spinal anesthesia were randomized to receive prophylactic norepinephrine (3.2 μg/min) or phenylephrine infusion (40 μg/min). The primary outcome was the change of heart rate and blood pressure during the study period. The secondary outcomes were to compare maternal complications, neonatal outcomes, Apgar scores and umbilical blood acid-base status between the two vasopressors.ResultsThere was no significant difference observed for the change of heart rate between two vasopressors. The mean standardized area under the curve of heart rate was 78 ± 12 with norepinephrine vs. 74 ± 11 beats/min with phenylephrine (mean difference 4.4, 95%CI − 0.1 to 9.0; P = .0567). The mean standardized area under the curve of systolic blood pressure (SBP) was significantly lower in parturients with norepinephrine, as the mean of differences in standardized AUC of SBP was 6 mmHg, with a 95% CI from 2 to 9 mmHg (P = .0013). However, requirements of physician interventions for correcting maternal hemodynamical abnormalities (temporary cessation of vasopressor infusion for reactive hypertension, rescuing vasopressor bolus for hypotension and atropine for heart rate less < 50 beats/min) and neonatal outcomes were also not significantly different between two vasopressors.ConclusionInfusion of norepinephrine was not associated with less overall decrease in heart rate during cesarean section for twins, compared with phenylephrine.Trial registrationChinese Clinical Trial Registry (ChiCTR1900021281).

Metabolic and blood acid-base responses to prepartum dietary cation-anion difference and calcium content in transition dairy cows

Dairy cows commonly undergo negative Ca balance accompanied by hypocalcemia after parturition. A negative dietary cation-anion difference (DCAD) strategy has been used prepartum to improve periparturient Ca homeostasis. Our objective was to determine the influence of a negative DCAD diet with different amounts of dietary Ca on the blood acid-base balance, blood gases, and metabolic adaptation to lactation. Multiparous Holstein cows (n = 81) were blocked into 1 of 3 dietary treatments from 252 d of gestation until parturition: (1) positive DCAD diet and low Ca (CON; containing +6.0 mEq/100 g DM, 0.4% DM Ca); (2) negative DCAD diet and low Ca (ND; -24.0 mEq/100 g DM, 0.4% DM Ca); or (3) negative DCAD diet plus high Ca supplementation (NDCA; -24.1 mEq/100 g DM, 2.0% DM Ca). There were 28, 27, and 26 cows for CON, ND, and NDCA, respectively. Whole blood was sampled at 0, 24, 48, and 96 h after calving for immediate determination of blood acid-base status and blood gases. Serum samples collected at -21, -14, -7, -4, -2, -1, at calving, 1, 2, 4, 7, 14, 21, and 28 d relative to parturition were analyzed for metabolic components. Results indicated that cows fed ND or NDCA had lower blood pH at calving but greater pH at 24 h after calving compared with CON. Blood bicarbonate, base excess, and total CO2 (tCO2) concentrations of cows in ND and NDCA groups were less than those of cows in CON at calving but became greater from 24 to 96 h postpartum. The NDCA cows had lower blood bicarbonate, base excess, and tCO2 at 48 h and greater partial pressure of oxygen after calving compared with ND. Cows fed ND or NDCA diets had lower serum glucose concentrations than CON cows before calving but no differences were observed postpartum. Serum concentrations of total protein and albumin were greater prepartum for cows in ND and NDCA groups than for those in CON. Postpartum serum urea N and albumin concentrations tended to be higher for ND and NDCA cows. Cows fed ND or NDCA diets had elevated serum total cholesterol concentration prepartum. During the postpartum period, triglycerides and NEFA of cows fed ND or NDCA diets tended to be lower than those of CON. Cows fed the NDCA diet had greater postpartum total cholesterol in serum and lower NEFA concentration at calving than ND. In conclusion, feeding a prepartum negative DCAD diet altered blood acid-base balance and induced metabolic acidosis at calving, and improved protein and lipid metabolism. Supplementation of high Ca in the negative DCAD diet prepartum was more favorable to metabolic adaptation to lactation in dairy cows than the negative DCAD diet with low Ca.

Effects of Elemental Mercury Vapor Inhalation on Arterial Blood Gases, Lung Histology, and Interleukin-1 Expression in Pulmonary Tissues of Rats.

We investigated the effects of elemental mercury vapor inhalation on arterial blood gases (ABGs), lung histology, and interleukin-1 (IL-1) expression in pulmonary tissues in rats. A total of 42 Sprague Dawley rats were divided randomly into three groups. Rats in the first group were used as the control (CG). A short-term group (STG) and a long-term group (LTG) were exposed to 500 μg/m3 of mercury vapor 2 hrs/day for 21 days and 65 days, respectively. After exposure periods were completed, arterial blood samples were obtained, and ABGs were measured. Lung tissue sections were prepared for histology evaluation and immune-stained to detect IL-1 expression. There was a significant decrease in body weight in both STG (15%) and LTG (22%) compared with the CG. In the LTG, six out of 14 (43%) rats died, including two males and four females, while none of the rats in the STG died during the experiment. In both STG and LTG, a significant acid-base imbalance was characterized by a significant decrease in blood pH values and a significant increase in PCO2 values. Both PO2 and SpO2 blood values were significantly decreased in the STG and LTG, while no changes were observed in HCO3 values in all groups. Histological evaluation of lung tissues revealed severe lesions characterized by pulmonary emphysema and inflammatory cellular infiltrate. IL-1 expression in lung tissues was not significantly different between exposed rats and control subjects. These results indicate significant alterations in blood acid-base status characterized by severe respiratory acidosis with hypoxemia and no evidence of compensatory alkalosis in rats after exposure to short- and long-term elementary mercury vapor.

The effects of post-operative oxygen supply on blood oxygenation and acid-base status in rats anaesthetized with fentanyl/fluanisone and midazolam.

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.

UMBILICAL CORD BLOOD ACID-BASE STATUS IN NEWBORNS WITH CONGENITAL HEART DISEASE IN A CARDIOVASCULAR REFERRAL CENTER IN COLOMBIA

Introduction: Congenital heart diseases (CHD) represent the most frequent group of congenital disorders, with an incidence of 8 to 10 per 1000 live births. The aim of this study was assess the correlation between the presence of CHD and the acid base status of the umbilical cord blood at the Fundación Cardiovascular de Colombia during the period 2007-2018. Materials And Methods: Retrospective descriptive study in FCV, prior to authorization of the ethics committee, medical records were reviewed and with ICD10 codes the patients with CHD were identied everyone with prenatal echocardiography, CHD incompatible with life or incomplete records were excluded, It took a sample of arterial blood from the umbilical cord, the sample was processed in a gases machine (i-STAT300F), the data was collected in Excel, the heart diseases were classied according to the cardiopathophysiological classication, the association measure was -X2 Results: we met 111 patients with CHD, 56.7% men, in total 367 specic defects, grouped into 4 groups (IPB, DBPF, OBNSD and NSBC) with 157, 50, 77 and 58 respectively. The pH, HCO3, Pco2, Po2 in general without alterations. However, when we compare DPBF, it had an increase in the incidence of acidosis and mortality statistically signicant p = 0.005. Conclusions: according to the ndings, we can afrm that there are specic heart diseases such as DPBF, which predispose worse results, including acidosis and perinatal asphyxia. It also means that the changes in acid-base state in patients with CHD are not simply physiological variations, but are indicators of pathology and mortality, just as in patients without CHD.

Взаимосвязь кислотно-основного состава пуповинной крови с развитием гипоксически-ишемической энцефалопатии у новорожденного

Взаимосвязь кислотно-основного состава пуповинной крови с развитием гипоксически-ишемической энцефалопатии у новорожденного

Daily dynamic changes of blood acid-base status and vital parameters in lambs and goat kids over the first seven days after birth

The current study aimed to monitor how blood acid-base status and vital parameters, including rectal temperature (RT), heart rate (HR), respiratory rate (RR), change in lambs and goat kids over the first week of life. Ten female Comisana lambs and 10 female Maltese goat kids were enrolled in the study. For each animal, RT, RR, HR measurement and blood sampling were daily performed from birth for a 7 day period (Day1–Day7). RR and HR decreased throughout study period (P < 0.05) in both species; pH showed lower values at Day1, Day2 and Day3 compared to Day6 and Day7 in lambs. Increased pO2 values were found in lambs and goat kids during the first 5 days after birth (P < 0.05). Lambs and goat kids showed higher pCO2 values during the first hours of life than the rest of study period (P < 0.05). Higher HCO3− values were found at Day1 and at Day4 compared to the rest of study period in lambs (P < 0.05). RT, RR, HR and pCO2 displayed a significant negative correlation with time in both lambs and goat kids, whereas, the pH values resulted positively correlated with time. In both species RT values were negatively correlated with pH and pO2, and positively correlated with pCO2; RR and HR resulted negatively correlated with pH and pO2, and positively correlated with pCO2. The observed changes reflect the physiological adjustments likely to occur in a newborn animal following transition from the controlled uterine environment to the free-living state and emphasize the importance of a deep knowledge on these physiologic parameters for an early diagnosis of risk factors or any situations that involve an high-risk newborn.

Abomasal infusion of ground corn and ammonium chloride in early-lactating Holstein-Friesian dairy cows to induce hindgut and metabolic acidosis

Next to rumen acidosis, other forms of acidosis may also affect lactational performance of cows. Therefore, the effects of hindgut acidosis, induced via abomasal infusion of ground corn, and metabolic acidosis, induced via abomasal infusion of NH4Cl, were studied in cows in early lactation. Observations were made on intake and digestibility of nutrients, lactation performance, energy and N partitioning, blood acid-base status, and rumen and hindgut fermentation characteristics. In a 6 × 6 Latin square design, 6 rumen-fistulated, second-lactation Holstein-Friesian dairy cows (48 ± 17 d in milk) were subjected to 5 d of continuous abomasal infusions of water as control, or solutions of 2.5 mol of NH4Cl/d, 5.0 mol of NH4Cl/d, 3.0 kg of ground corn/d, or the combination of ground corn with either of the 2 NH4Cl levels, followed by 2 d of rest. Treatment solutions were administered via peristaltic pumps through infusion lines attached to the rumen cannula plug and an abomasal infusion line with a flexible disk (equipped with holes to allow digesta passage) to secure its placement through the sulcus omasi. A total mixed ration consisting of 70% grass silage and 30% concentrate (on dry matter basis) was fed at 95% of ad libitum intake of individual cows. The experiment was conducted in climate respiration chambers to determine feed intake, lactation performance, and energy and N balance. Abomasal infusion of NH4Cl affected the acid-base status of the cows, but more strongly when in combination with abomasal infusion of ground corn. Metabolic acidosis (defined as a blood pH < 7.40, blood HCO3 concentration < 25.0 mmol/L, and a negative base excess) was observed with 5.0 mol of NH4Cl/d, 3.0 kg of ground corn/d + 2.5 mol of NH4Cl/d, and 3.0 kg of ground corn/d + 5.0 mol of NH4Cl/d. Metabolic acidosis was associated with decreased milk lactose content, metabolic body weight, energy retained as protein, and fecal N excretion, and increased urine N excretion, and tended to decrease intake of nutrients. Digestibility of several nutrients increased with 5.0 mol of NH4Cl/d, likely as a result of decreased intake. Abomasal ground corn infusion resulted in hindgut acidosis, where fecal pH decreased from 6.86 without ground corn to 6.00 with ground corn, regardless of NH4Cl level. The decrease in fecal pH was likely the result of increased hindgut fermentation, evidenced by increased fecal volatile fatty acid concentrations. Hindgut acidosis was associated with decreased digestibility of nutrients, except for starch, which increased, and crude fat, which was not affected. No systemic inflammatory response was observed, suggesting that the hindgut epithelium was not severely affected by the more acidic conditions or barrier damage. Abomasal infusion of ground corn increased milk yield, milk protein and lactose yield, fecal N excretion, N use efficiency, and total energy retained as well as energy retained in fat, and reduced milk fat content and urine N excretion.

Effect of Dietary Crude Protein on Animal Performance, Blood Biochemistry Profile, Ruminal Fermentation Parameters and Carcass and Meat Quality of Heavy Fattening Assaf Lambs.

Simple SummaryThis study was designed to assess the optimal level of crude protein inclusion in the diet of heavy fattening Assaf lambs. Our results suggested that levels of crude protein between 134 and 173 g/kg DM (dry matter) influence the dry matter intake and performance of lambs, but no effects were observed on rumen function, animal health, or carcass and meat quality. To maximize growth performance, a minimum level of crude protein of 157 g/kg dry matter is needed, but protein content beyond that level does not improve meat quality and could worsen profitability.Thirty Assaf male lambs (30 ± 1.9 kg of body weight) were allocated to three groups fed diets differing in their crude protein (CP) contents (low protein (LP), 134 g CP/kg dry matter (DM); medium protein (MP), 157 g CP/kg DM; and high protein (HP), 173 g CP/kg DM) to test the effect of dietary protein content on animal performance, rumen function, animal health, and carcass and meat quality. Feed intake was recorded daily, and animals were weighed every second week. Lambs were blood-sampled to determine their acid–base status and biochemical profile. After 70 days of trial, lambs were slaughtered, and the ruminal content was collected to assess ruminal fermentation. Finally, carcass and meat quality were evaluated. Dry matter intake and average daily gain increased (p < 0.05) when increasing the level of dietary CP. There were not significant differences (p > 0.05) in the evaluated parameters in the rumen fluid of lambs. There were not significant differences in carcass or meat quality (p > 0.05) and in those parameters related to blood acid–base status. Several biochemical parameters showed differences depending on diet CP level (urea, protein, albumin, glucose, and calcium; p < 0.05). Feeding costs calculated in relation to cold carcass weight decreased when dietary CP decreased. The results suggested that a dietary protein content greater than 157 g/kg DM would be required to maximize growth performance in Assaf male fattening lambs under 50 kg of body weight. However, a protein content beyond that level was not found to improve either carcass or meat quality and could worsen profitability.

Morphology and Function of Myocardium and Skin Microcirculation 24 Hours after Clozapine Poisoning

Aim of the study: to evaluate the effect of sublethal dose of clozapine on the rat cardiovascular system 24 hours after administration of the drug.Materials and methods. The experiments were carried out on 17 male Wistar rats weighing 220-270 g. Under general anesthesia with sevoflurane, the animals of Group I were enterally given 0.9% NaCl solution, Group II animals received clozapine in a dose of 150 mg/kg diluted in 2.0 ml of NaCl solution 0.9%, Group III animals were given clozapine in a dose of 150 mg/kg diluted in 2.0 ml of 40% ethanol. Blood pressure (BP), heart rate (HR), skin microcirculation using laser Doppler flowmetry (LDF), NADH and FAD+ fluorescence were estimated 24 hours after the drug administration. After euthanasia, autopsy with sampling of internal organs for morphological study was done. Then paraffin heart sections with subsequent H&amp;E staining were made, which were studied using the Nikon Eclipse Ni-U light microscope.Results. Spectral analysis of local skin blood flow fluctuations showed that clozapine reduced Amax and amplitude in all frequency ranges of active microcirculation regulatory system in comparison with the controls. No differences in blood gases and acid-base status were seen between the groups of animals 24 hours after administration of the drugs. However, the animals from clozapine groups (II and III) had lower hemoglobin and hematocrit than in the control group.Histological examination of rat hearts in groups II and III revealed congested venules, haemorrhages by dia-pedeses, perivascular and interstitial edema. The signs of blood stasis and marginalization of granulocytes were noted in the vascular lumen. Irregular staining of myocardium due to cardiomyocytes with hypereosinophilic and occasionally homogeneous cytoplasm, fragmentation and deformations of cardiac cells were revealed. Car-diomyocytic nuclei were polymorphic and irregularly stained, and perinuclear edema was observed.Conclusions. The results of the study demonstrate the toxic effect of clozapine manifesting as progressive myocardial alteration and disordered central and peripheral circulation. However, control of bradycardia, restored skin perfusion and metabolic improvement (diagnosed by NADH fluorescence and blood acid-base status) after 24 hours may be due to the activation of compensatory mechanisms, particularly through changes in neurogenic and humoral regulation of homeostasis.