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Chronic hypokalemia and intraoperative dysrhythmias
Insights
Chronic hypokalemia (low potassium) does not increase the risk of intraoperative dysrhythmias during anesthesia. Pre-existing dysrhythmias, not potassium levels, were the primary predictor of intraoperative arrhythmias.
Area of Science:
- Anesthesiology
- Cardiology
- Internal Medicine
Background:
- Hypokalemia is a common electrolyte imbalance.
- Its association with intraoperative dysrhythmias is not well-established.
Purpose of the Study:
- To determine if chronic hypokalemia increases the incidence of intraoperative dysrhythmias.
- To identify predictors of intraoperative dysrhythmias.
Main Methods:
- Intraoperative electrocardiograms (ECGs) were recorded for normokalemic (N=88) and hypokalemic (N=62) patients.
- Serum potassium and pre-operative ECGs were analyzed; continuous monitoring was performed.
- Multivariate analysis identified predictors of dysrhythmias.
Main Results:
- The hypokalemic group had more hypertensive and ASA Class III patients.
- No significant difference in dysrhythmia incidence was found between groups.
- Intraoperative dysrhythmias correlated only with pre-operative dysrhythmias.
Conclusions:
- Chronic hypokalemia itself is not associated with increased intraoperative dysrhythmias.
- Pre-existing dysrhythmias are the key risk factor for intraoperative arrhythmias.
Abstract:
To investigate whether chronic hypokalemia increases the occurrence of dysrhythmias during anesthesia, the authors recorded the intraoperative electrocardiograms of normokalemic (K+ = 5.0 -3.5 mEq/l; N = 88) and chronically hypokalemic patients (K+ = 3.4 - 2.6 mEq/l; N = 62). In each patient, serum potassium was measured and a 12-lead ECG was analyzed prior to surgery. No patient received potassium perioperatively. Lead II was monitored continuously during anesthesia, either by a Holter monitor (N = 81) or by a trained observer (N = 69). A variety of general anesthetic techniques were utilized, without consideration for the potassium level. The hypokalemic population had a higher incidence of hypertensive and ASA Class III patients (P = 0.03). Analysis of variance revealed no significant difference in the incidence of other characteristics between the hypokalemic and normokalemic groups: age, hypoxemia, cardiac disease, preoperative dysrhythmias, digitalis therapy, surgical site, anesthetic agent, and intubation. The method of ECG monitoring did not affect the incidence of dysrhythmias recorded. Multivariate analysis revealed that the occurrence of intraoperative dysrhythmias correlated with the presence of preoperative dysrhythmias only. The authors conclude that chronic hypokalemia per se is not associated with a higher incidence of intraoperative dysrhythmias.