Venous pH Values Research Articles

Routine umbilical cord blood gas determinations?

Between 1986 and 1988, 1924 term nulliparous patients with spontaneous onset of labor were studied to assess the importance of obtaining umbilical cord blood gas levels on all deliveries. The umbilical cord arterial and venous pH values (expressed as mean ± 2 SD) were 7.24 ± 0.14 (n = 1694) and 7.32 ± 0.12 (n = 1820), respectively. The incidence of newborn depression (1- or 5-minute Apgar score < 7) was 14.1 %; of these depressed newborns, the incidence of normal umbilical cord arterial pH values (< -2 SD) was 77.8%. Of the vigorous newborns, there was a 2.1% incidence of umbilical cord arterial blood acidemia. Umbilical cord arterial blood acidemia in vigorous newborns was not highly predictive of specific morbidity in the immediate newborn period. Regression analysis demonstrated the umbilical cord arterial pH to correlate best with the Apgar scores when compared with all other arterial or venous blood gas meaurements. We reached the following conclusions: (1) that obtaining cord arterial pH values in vigorous newborns should be considered since the values will provide objective documentation or normal fetal acid base balance in 98% of infants. (2) Only a cord arterial pH determination is recommended since it reflects fetal or newborn status more accurately than all other measurements. Additional measurements increase the likelihood of abnormal results and do not contribute to neonatal management. (3) An umbilical cord blood pH value is extremely useful in ruling out the diagnosis of birth asphyxia in the depressed newborn.

The use of labetalol for attenuation of the hypertensive response to endotracheal incubation in preeclampsia

Twenty-five women with preeclampsia who were scheduled to undergo cesarean section under general anesthesia were randomly assigned to either a labetalol pretreatment group (n = 15) or a control group (n = 10) who did not receive any antihypertensive therapy before the induction of anesthesia. Patients in the labetalol group received 20 mg of labetalol intravenously followed by 10 mg increments up to a total dose of 1 mg/kg, which resulted in moderate reductions in the maternal mean arterial pressure and heart rate with attenuation of the hypertensive and tachycardiac responses to laryngoscopy and endotracheal intubation. In the labetalol group there was no excessive reduction in the mean arterial pressure with the use of isoflurane and the usual amount of blood loss that occurred during cesarean section. The neonatal Apgar scores and umbilical arterial and venous pH and blood gas values were similar in the two groups. Side effects such as hypotension, bradycardia, and hypoglycemia were not seen in the neonates in the labetalol treatment group.

The usefulness of peripheral venous blood in estimating acid-base status in acutely III patients

The usefulness of peripheral venous sampling in determining acid-base status in acutely ill patients was studied. A total of 171 nonarrest patients and 12 patients in cardiac arrest had paired samples of arterial and venous blood compared for correlation of blood gas results. Linear equations relating arterial and venous values of pH, PCO2, and bicarbonate were developed in both groups of patients; however, the accuracy of predicting arterial values from venous values was limited. Severe acid-base disturbances were essentially ruled out by normal or nearly normal venous blood gases. Extremely abnormal venous levels reliably reflected comparable arterial abnormalities. The results suggest that immediate intravenous bicarbonate therapy should be considered for patients with pH less than or equal to 7.05 and PCO2 less than or equal to 40 torr despite the possibility of inadvertent venous sampling. A larger series is needed to verify these results in the setting of cardiac arrest.

Oxygen and carbon dioxide transporting properties of the blood of three sublittoral species of burrowing crab

1. A study has been made of the oxygen and carbon dioxide transporting properties of the blood of three species of crab,Goneplax rhomboides, a species which constructs semi-permanent burrows in sublittoral muds, andAtelecyclus rotundatus andLiocarcinus depurator which simply bury themselves in the substratum. Investigations were also made of thein vivo blood/gas parameters in these three species. The oxygen carrying capacity of the blood was similar in all three species (0.31–0.34 μmol·ml−1) as were arterial and venous oxygen tensions. Arterial and venous blood pH values were not significantly different but inL. depurator pHa was 8.08 compared with 7.81 in the other two species. At pH 7.8 and 10°C the oxygen affinity of the blood ofA. rotundatus (P50=5.6 Torr) andG. rhomboides (P50=4.1 Torr) was higher than that ofL. depurator (P50=24.3 Torr). Oxygen affinity was relatively temperature independent between 5–15°C inA. rotundatus and inL. depurator butG. rhomboides exhibited a normal temperature dependence (ΔH=−64 kJ·mole−1). The Bohr effect was much larger inL. depurator (ϕ=−1.43) than inA. rotundatus (ϕ=−0.92) andG. rhomboides (ϕ=−0.59). 2. The haemocyanin of all three species exhibited a pronounced lactate effect i.e. an increase in blood lactate concentration increased the oxygen affinity of the haemocyanin, and inA. rotundatus it was also possible to demonstrate the existence of an unidentified factor in the blood which slightly increased the oxygen affinity of the haemocyanin. InA. rotundatus and inL. depurator, but not inG. rhomboides, an increase in blood lactate concentration caused a decrease in the cooperativity of the haemocyanin. 3. The blood ofA. rotundatus, G. rhomboides andL. depurator had a high capacitance for CO2 transport at physiological CO2 tensions and also exhibited a distinct Haldane effect, the magnitude of which differed between these species. The buffer value of the blood of these crabs was low (Δ[HCO3]/ΔpH=−4.93 to −5.99 mmol·l−1·pH unit−1). The observed differences in the oxygen and carbon dioxide transporting properties of the blood of these three species of crab are discussed in relation to their mode of life.

The effect of prolonged exposure of pregnant rats to high ambient temperature on several constituents of the genital tract's fluids

1. 1. Various constituents of the genital tract's (GT) fluids were measured in heat-exposed rats (kept for at least 30 days at 35 ± 1 °C) and control rats (maintained at 22 ± 2°C). 2. 2. There were no differences between the groups in the GT fluid volume, protein, free amino acids and glucose contents. 3. 3. Arterial and venous blood glucose levels, pO 2 and pH values were similar in both groups. 4. 4. GT fluid protein hydrolysate from heat-exposed rats showed significantly reduced contents of glycine and alanine and elevated contents of valine and lysine as compared with controls. 5. 5. The GT fluid's free amino acid components showed reduced glycine and elevated valine and isoleucine in the heat-exposed group as compared with controls. 6. 6. Progesterone levels in GT fluid of heat-exposed rats was 60% higher than that of controls. 7. 7. It is suggested that the higher progesterone concentration and the altered relative contents of several free amino acids with a possible change in the proteins of the GT fluid may affect the development of the embryo in heat-exposed rats.

Study of 5-hydroxytryptamine (serotonin) in pericardial fluid in different causes of death (II.). Experimental study of 5-HT levels in two types of shocks (hemorrhagic and septic) in dogs.

In the present work we studied the levels of 5-HT in the pericardial fluid of 160 cadavers according to cause of death; such as myocardial infarction, violent asphyxia, pulmonary embolism, infections, bronchopulmonary diseases, traumatic and hemorrhagic diseases in the CNS, and multiple traumatism. We did not find significant differences in the various causes of death. A complementary study of 20 dead dogs having suffered induced shock, either hemorrhagic or septic, was made. In both series we studied the serum levels of 5-HT and the following parameters: systolic and diastolic arterial pressures, central venous pressure, hematocrit value, pH value, total proteins, albumin, PO2, and PCO2. We found the significant correlation (r = 0.828, P less than 0.01) only between 5-HT serum levels and the systolic arterial pressure in the hemorrhagic shock.

Mixed venous and arterial pH: A comparison during hemorrhagic shock and hypothermia

Under normal conditions a linear relationship exists between venous and arterial pH values. However, with severe metabolic and hemodynamic stress this correlation has not been established. To evaluate this relationship, nine dogs were subjected to 60 minutes of hemorrhagic shock at a mean arterial pressure of 30 mm Hg and were then resuscitated. Seven dogs were rendered hypothermic by surface cooling. Serial arterial and mixed venous samples for blood gas analysis were obtained from the femoral artery, superior vena cava (SVC), right atrium (RA), and pulmonary artery (PA). There were no statistical differences between mixed venous pH values obtained from SVC, RA, and PA during any study time. The differences between arterial and mixed venous pH (AVpH) had a significant linear relationship (r greater than 0.90, P less than 0.01). The AVpH during hypothermia was +.03 to +.04 pH units. The greatest AVpH occurred during shock, and ranged from +.08 to +.20 pH units. During recovery AVpH was intermediate at +.04 to +.13. It appears that during hemorrhagic shock and moderate hypothermia, a significant relationship persists between mixed venous and arterial pH. The mixed venous sample can be obtained from the superior vena cava, right atrium, or pulmonary artery.

Comparison of Brachial Venous and Mixed Venous Blood Gas Tensions and pH Values in the Chicken

Differences in blood gas tensions and pH between brachial venous blood (BVB) and mixed venous blood obtained from the pulmonary artery (PAB) were compared in anesthetized male White Leghorn chickens to determine if BVB as obtained in routine venipuncture could be used to estimate mixed venous values of pO2, pCO2, and pH.When paired samples were compared over the range of 25 to 68 mm Hg, brachial pO2 was 5.7 mm Hg higher (P<.001) than PAB pO2. Brachial pCO2 was 4.25 mm Hg higher (P<.001) than PAB pCO2 over the range of 17 to 56 mm Hg. Brachial pH was .066 units lower (P<.001) than comparable values for PAB over the range of 7.2–7.6 pH units.Regression equations are given for estimating mixed venous blood gas tensions and pH values from blood samples taken from the brachial vein.

Anaesthetic induction for Caesarean section with propanidid.

Propanidid was used for the induction of anaesthesia at Caesarean section in 50 healthy mothers. All parturients were considered to have normal placental function. Anaesthesia was maintained with nitrous oxide, oxygen, muscle relaxant and controlled ventilation. The patients were tilted laterally with a 15 degrees rubber wedge during the procedure in order to obviate the effects of aorta-caval occlusion. At the time of delivery, arterial blood was drawn from the mother and from the vessels of a double clamped section of umbilical cord, for blood-gas analysis. The results obtained are compared with those previously reported in a similar series anaesthetised with thiopentone, gas, oxygen and relaxant. Maternal blood-gas and acid-base levels were similar in the two groups at delivery. The clinical status of the infants in the present series, as judged by the modified Apgar score at 2 minutes after birth, was satisfactory. Umbilical venous and arterial pH values after propanidid were both 0-054 units (P less than 0-001) less than those following thiopentone; and average base deficits were 3-1 (Uv) and 3-9 (Ua) mEq/litre greater after propanidid (P less than 0-001). Mean oxygen levels in the umbilical cord bloods were 8-0 (Uv) and 3-5 (Ua) mmHg lower (P less than 0-001 & P less than 0-025 respectively) in the propanidid group. Derived oxygen contents was also significantly less than in the previous thiopentone series. (Ma-Uv) and (Ma-Ua) gradients were 0-053 and 0-051 pH units higher after propanidid than that following thiopentone (P less than 0-001). Mean (Ma-Uv) and (Ma-Ua) base deficits were 3-5 and 3-9 mEq/litre greater (P less than 0-001). Five patients offered definite evidence of factual recall, of whom three experienced pain. Propanidid, therefore, appeared to be associated with a greater degree of foetal acidaemia than did thiopentone. In addition, painful factual recall during surgery was encountered in 6 percent of cases. It is concluded that propanidid, although theoretically offering advantages over thiopentone to the obstetric anaesthetist, in practice, did not fulfil this promise.

Measurement of jugular venous blood gases for prediction of brain ischaemia following carotid ligation. A comparison with direct measurements of cerebral blood flow.

Measurements of various indices derived from arterial and jugular venous blood gas and pH values during temporary carotid clamping have been compared with measurements of cerebral blood flow and internal carotid artery pressure in 15 patients referred for carotid ligation. Cerebral venous blood gas measurements did not provide a reliable index of cerebral ischaemia.

Oxygen affinity of bird embryo blood

Oxygen dissociation curves have been determined for whole blood from chicken and duck embryos, hatchlings and adults using the technique of Longmuir and Chow (1970). The oxygen affinity was considerably higher than reported previously. The functional significance of the O2-dissociation curve obtained in the present study is discussed in relation to arterial and venous PO2 and pH values reported in the literature.

Alterations to Whole Blood pH, pCO2 and Plasma Bicarbonate Index Values During a Metabolic Acidosis Occasioned by Neonatal Diarrhoea in Thoroughbred Foals

Twenty-one foals with neonatal diarrhoea for more than 24 hours were examined for whole blood pH, p v CO 2 and bicarbonate “index” in plasma. The sick foals were subdivided into those neither sucking nor drinking water and those off-suck alone. There was a significant difference ( P < 0 · 05) between the whole blood pH of these groups. The mean p v CO 2 and bicarbonate “index” between the groups and from normal foals were also significantly different. Five hundred ml. 5 per cent sodium bicarbonate was given to each foal when venous pH and bicarbonate index values were below 7 · 35 and 24 m-equiv./l. respectively. All the foals recovered. Recovery was complete when the foal was sucking vigorously from the mare and there had been no sign of diarrhoea for a period of at least 24 hours. Arterial and venous pH, pCO 2 and total bicarbonate values from five foals were compared. A detailed case history of one clinical case is presented. Le pH sanguin total, le p v CO 2 et l’indice de bicarbonate dans le plasma ont été analysés chez 21 poulains avec diarrhée néo-natale pendant plus de 24 heures. On a réparti les poulains malades d’après ceux qui ne tétaient pas et ne buvaient pas d’eau, et ceux qui ne tétaient plus seulement. Il y avait une différence sensible ( P < 0,05) entre le pH sanguin total de ces groupes. Les valeurs moyennes du p v CO 2 et de l’indice de bicarbonate entre ces groupes et les poulains normaux étaient aussi sensiblement différentes. Quand les valeurs du pH veineux et de l’indice de bicarbonate étaient en-dessous de, respectivement, 7,35 et 24 m-équivalent/l., on a donné 500 ml. et 5 pour cent de bicarbonate de sodium à chaque poulain. Tous les poulains se sont remis. La guérison était complète lorsque le poulain tétait avidement la génisse et ql’aucun signe de diarrhée n’avait été observé pendant une période de 24 heures, au moins. On a comparé le pH veineux et artériel, le pCO 2 et les valeurs totales de bicarbonate de cinq poulains. L’historique d’un cas clinique est présenté en détail. Bei einundzwanzig Fohlen mit neonataler Diarrhoe, die für über 24 Stunden bestanden hatte, wurden die Gesamtblut-pH- und p v CO 2 Werte sowie der Plasma-Bikarbonat-Index bestimmt. Die erkrankten Fohlen wurden in jene unterteilt, die weder saugten, noch Wasser tranken und in jene, die nur das Euter ablehnten. Zwischen den Gesamt-blut-pH-Werten dieser Gruppen bestand ein wesentlicher Unterschied ( P < 0,05). Zwischen den Minimum-p v CO 2 -Werten und dem Bikarbonatindex dieser beider Gruppen und den bei gesunden Fohlen gewonnenen Werten bestanden ebenfalls wesentliche Unterschiede. Wenn die venösen pH- und Bikarbonatindexwerte unter 7,35 bzw. 24 m-Äquiv./l. fielen, erhielten die Fohlen je 500 ml. einer 5-prozentigen Natriumbikarbonatlösung. Alle Fohlen erholten sich. Die Genesung wurde alls vollständig betrachtet, wenn seit mindestens 24 Stunden keine Anzeichen einer Diarrhoe beobachtet wurden und die Fohlen gut saugten. Die arteriellen und venösen pH-, pCO 2 - und Gesamt-Bikarbonat-Werte von fünf Fohlen werden verglichen. Die eingehende Krankengeschichte eines klinischen Falles wird angeführt. Veintiún potrillos con diarrea neonatal por más de veinticuatro horas fueron examinados de pH sang íneo total, p v CO 2 e índice de bicarbonato en plasma. Los potrillos enfermos fueron subdivididos en aquéllos que no bebieron ni mamaron y en aquéllos que que fueron retirados del pecho solamente. Hubo una diferencia significativa de ( P < 0,05) entre el pH sanguíneo de los dos grupos. El promedio del p v CO 2 y del índice del bicarbonato entre los grupos con respecto a los potrillos normales mostró también diferencias significativas. Quinientos ml y 5 por ciento de bicarbonato de sodio fue dado a cada potrillo cuando el pH y el índice del Bicarbonato fue menor de 7,35 y 24 m-equiv./l. respectivamente. Todos los potrillos se recuperaron. La recuperación fue completa cuando el potrillo estuvo mamando vigorosamente de la yegua y no hubo signos de diarrea por un período por lo menos de 24 horas. Valores de pH, pCO 2 y debicarbonato total, tanto venoso como arterial de cinco potrillos se comparan. Se presenta una historia clínica detallada.

Effect of chronic hypoxia on the pulmonary arterial blood pressure of the chicken

Effect of chronic hypoxia on the pulmonary arterial blood pressure of the chicken