Changes in plasma potassium concentration during acute acid-base disturbances☆

The induction characteristics of etomidate, a new i.v. hypnotic agent, were studied in 400 patients. Two hundred were premedicated with atropine and anaesthesia was induced with 0.2, 0.25, 0.3 or 0.35 mg/kg of etomidate. The remainder received one of four standard premedications and anaesthesia was induced with etomidate 0.3 mg/kg. Involuntary muscle movements occurred in more than 60% of patients receiving atropine alone. The frequency was reduced in the second group, but remained unacceptable in over 8% of patients. The incidence of other excitatory phenomena, such as cough and hiccup, was 10% approximately. Cardiovascular changes were minimal and no serious allergic phenomena were observed. Nausea and vomiting occurred after surgery in up to 30% of patients and was unrelated to the dose of etomidate or to premedication. Pain on injection occurred in up to 80% of patients when the drug was injected into small peripheral veins and occurred in more than % when using more proximal veins

Effect of dose and premedication on induction complications with etomidate

Severe life-threatening hyperkalaemia may occur following administration of suxamethonium during certain periods after burns, neurological injuries, and in certain other conditions. Although this response is well-known, there is disagreement about when it may occur. This review describes the normal hyperkalaemic response to suxamethonium, the factors affecting it, the conditions in which it may be exaggerated, and the periods of high risk.

Suxamethonium and Hyperkalaemia

Objective. To report the occurrence of life-threatening hyperkalaemia following treatment with therapeutic thiopentone coma.

Life-threatening hyperkalaemia following therapeutic barbiturate coma.

Potassium ( K + ) plays a significant part in the excitability of cardiac, neural and muscle cells. The evidence'-5 indicates that the excitability of these cells depends upon the ratio of intracellular to extracellular potassium concentrations. Disturbances of K + concentration affect cellular function more than structure and the signs and symptoms of the disturbances result from malfunction of excitable cell membranes.

https://associationofanaesthetists-publications.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2044.1973.tb00303.x

Potassium and the anaesthetist. A review.

Anaesthesia was induced in 60 healthy adults using four different induction agents with 15 individuals in each group. After induction, a dose of 50 mg suxamethonium was injected in all the patients. The serum potassium was recorded before induction (K1), after induction (K2) and after suxamethonium administration (K3). The fall in potassium during induction of anaesthesia was less than 3%, and there were no significant differences between the induction agents with regard to this initial potassium fall.



The potassium increase after suxamethonium, measured as the change from K2 to K3, ranged from 5.3% in the thiopentone group up to 12.7% in the halothane-nitrous oxide group. A multiple comparison test showed that the increase in the last group was significantly greater than in each of the three groups induced with thiopentone, diazepam or propanidid. No significant differences could be demonstrated among the three latter. When the smaller changes from K1 to K3 were used, the only two groups of patients differing significantly in the potassium rise were the halothane-nitrous oxide group compared with the thiopentone group alone.



ZUSAMMENFASSUNG

Bei 60 gesunden Erwachsenen wurde die Narkose mit 4 verschiedenen Einleitungsagentien eingeleitet, jeweils 15 in jeder Gruppe. Allen Patienten wurde nach der Einleitung je 50 mg Suxamethonium injiziert. Kaliumbestimmungen im Serum wurden vor der Narkoseeinleitung (K2), nach der Einleitung (K2) und nach der Suxamethoniumgabe (K3) vorgenommen. Der K-Abfall wahrend der Einleitung war geringer als 3% und bezuglich dieses initialen Absinkens des K-Spiegels gab es keine signifikanten Unterschiede zwischen den Einleitungsagentien.



Der Kaliumstieg nach Suxamethonium, gemessen als Unterschied zwischen K2 und K3, bewegte sich von 5,3% in der Thiopentalgruppe bis 12,7% in der Halothan-Lachgas-Gruppe. Der Mehrfach-Vergleichstest ergab, daβ der K-Anstieg in der letzten Gruppe signifikant hoher als in jeder der drei an-deren Gruppen war, bei denen die Einleitung mit Thiopental, Diazepam, bzw. Propanidid erfolgte. Zwischen den drei letzteren ergaben sich keine signifikanten Unterschiede. Wenn nur die kleineren Veranderungen zwischen K1 und K3 zum Vergleich herangezogen wurden, war der K-Anstieg in der Halothan-Lachgas-Gruppe lediglich gegenuber der Thiopentalgruppe signifikant erhoht.

R. Endresen

Papers

Suxamethonium Hyperkalaemia with Different Induction Agents