Prevalence of Electrolyte Disorders during the Immediate Postoperative Intensive Care - The Experience of a Large Brazilian Center

Introduction

The immediate postoperative period covers the 24 hours following any surgical intervention. During this period, due to the direct and indirect action of the pathology and surgical stress, there is an increased risk of organ and system involvement, bleeding and thromboembolic phenomena, leading in many cases to the need for intensive surveillance. Few studies to date have Prevalence of Electrolyte Disorders during the Immediate Postoperative Intensive Care - The Experience of a Large Brazilian Center addressed the prevalence of electrolyte disturbances during the immediate postoperative period, and yet they have only partially. The most important electrolytes in daily clinical practice are: Sodium, Bicarbonate, Potassium, Magnesium, Calcium and Phosphorus.

Electrolyte disturbances are reported as an important cause of morbidity and mortality in several clinical conditions. During surgical procedures, administration of Anaesth Critic Care Med J

crystalloids / colloids, medications and blood products in the operating room can potentially make these disorders more prevalent, suggesting the importance of studies addressing the prevalence of these changes and evidence of associated complications.

In 2012, Sakr Y, et al. published a study proposing an association between postoperative dysnatremia and increased morbidity and mortality in surgical patients admitted to the intensive care unit [1]. In 2013, Crestanello JA, et al. published a study proposing an association between postoperative hyponatremia and increased morbidity and mortality in patients undergoing cardiac surgery [2]. In 1989, Chernow B, et al. published studies revealing the high prevalence of hypomagnesemia in postoperative intensive care patients, and increased mortality and hypokalemia associated with severe hypomagnesemia (serum magnesium less than or equal to 1.0 mEq / dl ) [3]. In the same decade, studies confirmed the high prevalence of hypomagnesemia in patients in the immediate postoperative period of cardiac surgery [4] and in the immediate postoperative period of major gastrointestinal surgery [5, 6].

In 2016, Gai P, et al. published an observational study that revealed a high prevalence of hypocalcemia in patients in the immediate postoperative period of total knee arthroplasty [7]. In 1975, Martin E, et al. published a study on the effect of various crystalloid solutions on postoperative hydroelectrolytic balance [8]. In 1998, Ip- Yam PC, et al. published a study on the prevalence of changes in urea and electrolyte levels after parenteral fluid therapy during the perioperative period [9]. The objective of this observational research is to determine the overall prevalence of electrolyte disturbances of several surgeries that required intensive care during the immediate postoperative period.

Goals

To determine in a carefully selected group of patients, during immediate postoperative intensive care, the prevalence of electrolyte disturbances involving the serum concentration of sodium, potassium, calcium (in its ionic form), magnesium, bicarbonate and phosphorus. (First 24 hours postoperatively).

During the data collection period for the study, it was observed that 52% of patients were in the immediate postoperative period of bariatric surgery due to morbid obesity. Thus, it’s secondary objective was to evaluate whether, in this specific subgroup, the prevalence of electrolyte disturbances in the immediate postoperative period would be different in relation to patients undergoing other surgeries and without morbid obesity (48% of all pacients). Additionally, patients with electrolyte disturbances were followed during the immediate postoperative period for clinical complications.

Methodology

During February 9, 2011, to December 22, 2012, every patient in the immediate postoperative period admitted in intensive care units of a large brazilian hospital located in the city of Rio de Janeiro who met the inclusion criteria of the study (Table 1) had a plasma analysis made from blood samples collected in the first 6 hours after surgery to determine serum concentrations of sodium, potassium, magnesium, ionic calcium and phosphorus.

In the hospital where the study was conducted, it’s a routine in all intensive care units to take blood samples of every patient admitted after surgery. The author choosed to use restrictive selection criteria in an attempt to avoid interference from nefrological and endocrinological pathologies, and from the action of regularly used medications. • Admission in ICU unit and blood sample collecting until 6 hours after surgery

Following this laboratory screening, patients with laboratory abnormalities were followed during the immediate postoperative period for possible complications during 24 hours.

The laboratory parameters of normality used in this study are shown in table 2.

Conclusion

The most prevalent electrolyte disturbance in the total group of selected patients was hypomagnesemia, followed by hypocalcemia and hypokalemia. No cases of hyperkalaemia were observed, making it the least prevalent electrolyte disorder in the general group and in both subgroups. The second least prevalent electrolyte disorder was hypercalcemia. The researchers observed that the subgroup of non-morbidly obese patients had a higher relative prevalence of hypokalemia and hypomagnesemia, and that the morbidly obese subgroup had a higher relative prevalence of hypocalcemia, but without statistical significance (p value greater than 0.05). Despite the high prevalence of hypomagnesemia and hypocalcemia, no clinical complications that could be associated with these electrolyte disturbances were observed in all the patients that joined this study.