scholarly journals Haemoglobin function in intact lamprey erythrocytes: interactions with membrane function in the regulation of gas transport and acid-base balance.

1995 ◽  
Vol 198 (12) ◽  
pp. 2423-2430 ◽  
Author(s):  
M Nikinmaa ◽  
S Airaksinen ◽  
L V Virkki
Keyword(s):  
Carbon Dioxide ◽  
Gas Transport ◽  
Oxygen Affinity ◽  
Oxygen Binding ◽  
Acid Base Balance ◽  
Acid Base ◽  
Red Cell Membrane ◽  
Membrane Function ◽  
Acid And Base ◽  
Base Balance

Haemoglobin function within lamprey erythrocytes offers a unique solution to gas transport among vertebrates. Lamprey haemoglobin within intact erythrocytes is in oligomer/monomer equilibrium and has an oxygen affinity similar to that of haemoglobin in other active fishes. The cooperativity of oxygen binding, which is reduced at low pH values, the effect of protons and the effect of the concentration of haemoglobin on its oxygen affinity are all due to dissociation/association reactions of the haemoglobin molecules. The permeability of the lamprey red cell membrane to acid and base equivalents is very low, and plasma bicarbonate cannot therefore be dehydrated to carbon dioxide to any significant extent during the residence time of blood in the gills. This potential limitation on carbon dioxide excretion is overcome, however, by the high intraerythrocytic pH and the marked oxygenation-linked pH changes in the erythrocyte, which are due to the large Haldane effect of the haemoglobin. Owing to the relative impermeability of the erythrocyte membrane to acid equivalents, intraerythrocytic haemoglobin cannot take part in the acid-base buffering of the extracellular compartment. As a consequence, extracellular acid loads cause marked fluctuations in plasma pH.

Gas transport and blood acid-base balance in diving sea snakes

1975 ◽  
Vol 191 (2) ◽  
pp. 169-181 ◽  
Author(s):  
R. S. Seymour ◽  
M. E. D. Webster
Keyword(s):  
Gas Transport ◽  
Acid Base Balance ◽  
Acid Base ◽  
Sea Snakes ◽  
Base Balance

scholarly journals Carbon dioxide removal in acetate hemodialysis: Effects on acid base balance

1984 ◽  
Vol 25 (5) ◽  
pp. 830-837 ◽  
Author(s):  
Juan P. Bosch ◽  
Sheldon Glabman ◽  
George Moutoussis ◽  
Mario Belledonne ◽  
Beat von Albertini ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Removal ◽  
Acid Base Balance ◽  
Acid Base ◽  
Base Balance

scholarly journals Haemolymph Acid-Base, Electrolyte and Gas Status during Sustained Voluntary Activity in the Land Hermit Crab (Coenobita Compressus)

1986 ◽  
Vol 125 (1) ◽  
pp. 225-243
Author(s):  
Michéle G. Wheatly ◽  
Brian R. Mcmahon ◽  
Warren W. Burggren ◽  
Alan W. Pinder
Keyword(s):  
Hermit Crab ◽  
Oxygen Binding ◽  
Acid Base Balance ◽  
Acid Base ◽  
Voluntary Activity ◽  
Binding Characteristics ◽  
Base Balance ◽  
External Water ◽  
O2 Delivery

After 3h(50 m) of voluntary walking, the haemolymph pH of the land hermit crab Coenobita compressus (H. Milne Edwards) decreased by 0.4units. This was accompanied by increases in CO2 tension (Pcoco2). bicarbonate (HCO3− + CO32-) and lactate concentrations. The hypercapnic acidosis was partially compensated by metabolic bicarbonate accumulation and an H+ deficit developed. Unloaded crabs accumulated less of a proton load than crabs transporting mollusc shells. During activity, oxygenation of the haemocyanin (HCy) accounted for the release of 0.3 mmol CO2l−1, via the Haldane effect, which was seven times more than in settled crabs. Control acid-base balance was re-established within 1 h of recovery. At this time, acidic equivalents were excreted at a mean flux rate of 5 mequiv kg−1 h−1 into a source of external water. [Na+] and the ratio of [Na+]:[Cl−] increased during exercise. Coenobita haemolymph had a high O2-carrying capacity (CmaxHCyOHCyO2 = l.55 mmol 1−1). HCy oxygen-binding characteristics were typical of other decapods (φ= −0.44), yet no lactate sensitivity was apparent. Settled in vivo values of O2 tension (Poo2) and content (Coo2) were located around the half-saturation tension (P50) of the dissociation curve. During exercise, POO2 increased and an unopposed Bohr shift decreased the O2-binding affinity, thereby reducing postbranchial saturation. Quantitatively, however, compensations in cardiac output (V·b) were more instrumental in increasing the O2 delivery to respiring tissues. During recovery, haemolymph POO2 remained high and the venous reserve doubled.

Clinical Biochemistry

PEDIATRICS ◽  
1955 ◽  
Vol 16 (6) ◽  
pp. 908-908
Author(s):  
HENRY B. BULL
Keyword(s):  
Carbon Dioxide ◽  
Clinical Biochemistry ◽  
Endocrine Function ◽  
Acid Base Balance ◽  
Acid Base ◽  
Carbon Dioxide Transport ◽  
Iron Sulfur ◽  
Short Summary ◽  
Base Balance ◽  
Practicing Physicians

This is the latest edition of a well-known textbook on clinical biochemistry designed essentially for use by advanced medical students and by practicing physicians. There are 12 chapters beginning with the metabolism of carbohydrates, lipids, proteins and nucleic acids and continuing through the metabolism of iron, sulfur, iodine, etc. There are chapters on electrolytes, water and acid-base balance and on oxygen and carbon dioxide transport. There is a lengthy and impressive section on endocrine function followed by a short summary of the vitamins.

FC 052ACID-BASE BALANCE DURING IN-SERIES EXTRACORPOREAL CARBON DIOXIDE REMOVAL AND CONTINUOUS VENOVENOUS HEMOFILTRATION: PREDICTIONS FROM A MATHEMATICAL MODEL

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
John (Ken) Leypoldt ◽  
Joerg Kurz ◽  
Jorge Echeverri ◽  
Markus Storr ◽  
Kai Harenski
Keyword(s):  
Carbon Dioxide ◽  
Mathematical Model ◽  
Tidal Volume ◽  
Carbon Dioxide Removal ◽  
Total Carbon ◽  
Acid Base Balance ◽  
Acid Base ◽  
Mechanically Ventilated ◽  
Base Balance ◽  
In Series

Abstract Background and Aims Critically ill acute kidney injury (AKI) patients may require treatment by extracorporeal carbon dioxide removal (ECCO2R) devices to allow protective or ultraprotective mechanical ventilation and avoid hypercapnic acidosis. Continuous venovenous hemofiltration (CVVH) and ECCO2R devices can be arranged in series to form a single extracorporeal circuit; such a circuit has been proposed to be optimal, based carbon dioxide removal efficacy, if the ECCO2R device is placed proximal to the CVVH device (Allardet-Servent et al, Crit Care Med 43:2570-2581, 2015). Method We developed a mathematical model of whole-body, acid-base balance during extracorporeal therapy using in-series ECCO2R and CVVH devices for treatment of mechanically ventilated AKI patients. Equilibrium acid-base chemistry in blood was assumed as reported previously (Rees and Andreassen, Crit Rev Biomed Eng 33:209-264, 2005). Published clinical data from Allardet-Servent et al of mechanically ventilated (6 mL/kg predicted body weight or PBW) AKI patients treated by CVVH without ECCO2R were used to adjust model parameters to fit plasma levels of arterial partial pressure of carbon dioxide (PaCO2) and arterial plasma bicarbonate concentration ([HCO3]). The effects of applying ECCO2R at an unchanged tidal volume and a reduced tidal volume (4 mL/kg PBW) on PaCO2 and [HCO3] were then simulated assuming carbon dioxide removal rates from the ECCO2R device measured in the clinical study (91 mL of CO2/min when ECCO2R was proximal and 72 mL of CO2/min when CVVH was proximal). Results Agreement of model predictions with the clinical data was good, and model predictions were relatively independent of the in-series position of the devices (see Table). Total carbon dioxide removal from the CVVH device via ultrafiltration predicted by the model was lower after applying ECCO2R at both the unchanged tidal volume (25 mL of CO2/min when ECCO2R was proximal and 39 mL of CO2/min when CVVH was proximal) and the reduced tidal volume (30 mL of CO2/min when ECCO2R was proximal and 44 mL of CO2/min when CVVH was proximal). The reduced removal of total carbon dioxide via ultrafiltration when ECCO2R was proximal resulted from the lower total carbon dioxide concentration in blood entering the CVVH device. Thus, independent of the in-series position of the devices, the magnitude of this difference in total carbon dioxide removal by the CVVH device (14 mL of CO2/min) approximately cancels out the relative greater efficacy of the ECCO2R device (19 mL of CO2/min). Conclusion The described mathematical model has quantitative accuracy. It suggests that overall acid-base balance when using ECCO2R and CVVH devices in a single, combined extracorporeal circuit will be similar, independent of their in-series position.

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