Preoperative hyponatremia predicts complications in older patients undergoing digestive tract surgery: a propensity score matching analysis

Chun-Qing Li,Hao Kong,Fan Yu,Chen Zhang,Chun-Mei Deng

doi:10.1007/s41999-021-00559-4

Abstract

Key summary pointsAimThis study aimed to investigate the association between preoperative hyponatremia and life-threatening postoperative complications (including death) among older patients undergoing digestive tract surgery.FindingsPreoperative hyponatremia was associated with an increased risk of life-threatening postoperative complications and mortality in older patients undergoing digestive tract surgery. Preoperative hyponatremia was also correlated with a higher risk of postoperative infectious complications.MessagePreoperative hyponatremia can predict the development of life-threatening postoperative complications and mortality in older patients undergoing digestive tract surgery.

Highlights

Hyponatremia, defined as a serum sodium ( [Na+]) concentration < 135 mmol/L, is a common electrolyte imbalance that occurs in many clinical settings [1]
104 patients remained in the hyponatremia group, and 208 patients remained in the normal [Na+] group, yielding a cohort of 312 patients for final analyses (Fig. 1)
In this retrospective cohort study, we found that preoperative hyponatremia was associated with an increased risk of life-threatening complications and mortality in older patients undergoing digestive tract surgery

Summary

Introduction

Hyponatremia is caused by a relative excess of water compared to sodium in the extracellular fluid (ECF), reflecting the pathophysiologic alternations in water homeostasis. Sodium and its accompanying anions are the major osmotically active plasma solutes and influence the osmotic movement of water across cell membranes; true hyponatremia is most commonly associated with hypo-osmolality (i.e., hypotonic hyponatremia) [2, 3]. Pseudohyponatremia, as a type of isotonic hyponatremia, is derived from a laboratory artifact: excess plasma protein or lipid reduces the water content of a given volume of plasma, thereby reducing the [Na+] concentration per unit of plasma; the [ Na+] concentration in the water phase is normal (e.g., in hyperproteinemia or hypertriglyceridemia) [2,3,4]. Given that hyponatremia can be induced by various diseases or abnormal conditions, it is usually regarded as the surrogate marker for certain underlying diseases or pathophysiological status such as frailty [2, 6, 7]

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