Fluid Overload Syndrome in Patients Undergoing Holmium Laser Enucleation of the Prostate (HoLEP)

Abstract

Introduction: Fluid overload syndrome is a potentially serious complication that can arise during holmium laser prostate enucleation (HoLEP) surgery. This minimally invasive surgical technique is used to treat benign prostatic hyperplasia (BPH) and is known for efficacy and safety. Fluid overload occurs when the patient receives excessive volume of intravenous fluids during the surgical procedure. This can occur due to a variety of factors, such as inadequate fluid administration by the medical team, excessive fluid absorption during irrigation, or systemic absorption of solutions used during surgery.

Material And Methods: A descriptive, observational, single-center and retrospective study was performed in patients undergoing prostatic enucleation with Holmium laser (HoLEP) who developed water overload syndrome, between April 2023-2024 in the Hospital Juarez of Mexico. The demographic data and the dependent variables will be tested for normality according to the Kolmogorov-Smirnov test with Lilliefors correction. If the data are normally distributed, factorial ANOVA will be used for more than two independent samples where the Bonferroni test will be used post Hoc for the multiple pairwise comparison in a parametric manner, considering p<0.05 as statistically significant; if the data are not normally distributed, the Kruskal- Wallis test will be used for more than two independent samples where the Dunn's test will be used post hoc for the multiple pairwise comparison in a non-parametric way, considering p<0.05 as statistically significant.

Results: We analyzed 142 files of patients who underwent HoLEP, of which only 49 met the expected inclusion criteria. Of the remaining 49 files, 100% were men with a median age 69 years  (58-79 years), weight 62 kg  (58-78 kg), height 1.67 m  (1.55-1.74 m), BMI 22.1 kg/m2  (21.7-25.8 kg/m2) and body surface area 1.69 m2  (1.61-1.71 m2). The hemodynamic and gasometrical variables were recorded at the anesthesia beginning, at 30, 60, 90, 120, 150 minutes and at the anesthesia end: At 60 minutes after Holmium enucleation the hemodynamic variables: systolic blood pressure 116 mm Hg (110-119 mm Hg), Diastolic blood pressure 63.5 mm Hg (56.5-67 mm Hg), Mean arterial blood pressure  81 mm Hg (76.3-83.3 mm Hg), Heart Rate 68.6 beats/minute (62.6-73.6 beats/minute), Pulse Variability 4.45% (1.7-7.2%) and Plethysmographic variability 5.2% (2.2-8.2%). As for the gasometrical variables: pH 7.34±0.02, CO2 partial pressure 32.24±1.80 mm Hg, O2 partial pressure 61.61±1.80 mm Hg, Arterial Bicarbonate 17.84±1.26 mmol/L, Base deficit -3.95±0.53 mmol/L, Arterial Sodium 135.78±1.41 mmol/L, Arterial Potassium 3.02±0.15 mmol/L, Arterial Chlorine 103.97±1.95 mmol/L, Arterial Lactate 1.76±0.22 mmol/L and Coefficient p50 26.59±0.98 mm Hg. After statistical analysis with Kruskal-Wallis and Dunn-Bonferroni method, the hemodynamic and gasometrical changes occurring after 60 minutes are statistically significant (p<0.05).

Discusion: In this cohort of patients with fluid overload, they respond to myocardial fiber distension to a variable degree by increasing cardiac output and stroke volume until dysfunction occurs due to myocardial insufficiency. Myocardial depression in turn produces microvascular dysfunction with alterations in the regulatory functions of the endothelium. This behavior is demonstrated by changes in systolic, diastolic, and average blood pressure that compensate for fluid overload within the first 90 minutes of surgery. Few studies have reported the clinical outcomes of patients undergoing HoLEP, with hemodynamic behavior variables being the least described. If this fluid infusion is continued through prostatic reabsorption of sodium chloride, heart failure occurs due to activation of the sympathetic nervous system accompanied by a greater predisposition to ventricular and supraventricular arrhythmias, which in our study occurred from a median of 71.5 Lt of NaCl and with a utilization rate of 0.27-0.49 lt/min.

Conclusions: Fluid overload syndrome due to HoLEP is a rarely diagnosed entity that leads to the appearance of hyperchloremic metabolic acidosis after 90 minutes of enucleation that can appear in up to 23.6% of patients, with an average of fluids infused of NaCl from 43.9 liters and in prostate resections from 48 gr. The rapid identification of this fluid overload syndrome will allow negative assessments, administration of drugs such as diuretics and even the diagnosis of ischemia-reperfusion that can be harmful in patients with previous renal failure.