Intraoperative hyperkalemia during laparoscopic pelvic surgery and prostatectomy.

To the Editor: A 48-year-old man (80 kg, 182 cm) was scheduled for a pelvic tumor resection on September 19, 2017. This case report is in accordance with the consensus-based clinical Case Reporting (CARE) guideline available through Enhancing the Quality and Transparency of Health Research (EQUATOR) network guidelines. His medical history only included cholecystectomy, which he underwent 5 years ago. Preoperative laboratory data were unremarkable (venous potassium level, 4.0 mmol/L). Electrocardiogram (ECG) revealed complete right bundle block and heart rate of 73 beats/min. On arrival in the operating room, an arterial line was introduced for continuous measurement of invasive arterial pressure. The preoperative arterial blood gas (ABG; GEM® Premier 3000; Instrumentation Laboratory Co., Bedford, MA, USA) analysis revealed a pH of 7.41, partial pressure of carbon dioxide (PCO2) level of 39 mmHg, HCO3− level of 25.1 mmol/L, and potassium level of 3.6 mmol/L. Subsequently, general anesthesia was induced with intravenous administration of anesthetics, and the anesthesia was maintained with a combination of inhaled and intravenous anesthetics. Lactated Ringer's solution (Hunan Kelun Pharmaceutical Co., Ltd., Hunan, China) and hydroxyethyl starch (Beijing Fresenius Kabi Pharmaceutical Co., Ltd., Beijing, China) were infused to maintain blood volume. The surgery was performed via a transperitoneal approach, and five ports were placed at the lower abdominal wall. The patient was placed in a 30° Trendelenburg position. During the operation, a large cystic tumor (∼7 cm diameter) was found bulged between the posterior wall of the bladder and the rectum. The pelvic tumor was densely adhered to the prostate and front rectal wall. The posterior bladder wall and rectal wall were injured during the tumor resection procedure. Presently, the ABG analysis revealed a pH of 7.26, PCO2 level of 50 mmHg, HCO3− level of 21.1 mmol/L, and potassium level of 3.7 mmol/L. Thereafter, an attending colorectal surgeon repaired the lesion of the rectal seromuscular layer for 1.5 h. After the completion of this procedure, the ABG analysis revealed a pH of 7.26, PCO2 level of 53 mmHg, HCO3− level of 22.1 mmol/L, and potassium level of 5.8 mmol/L. Although the circulatory system was stable and no obvious changes were observed on ECG, the arterial potassium level increased sharply. To verify the accuracy of this observation, once again, we drew the arterial blood and tested it with two blood gas analyzers of the same model. The results of potassium level were similar to the previous one. Then, insulin of 12 IU, 50% dextrose of 40 mL, and furosemide of 5 mg were injected. The arterial potassium level dropped to 4.6 and 4.1 mmol/L at 40 min and 2 h later, respectively. For en bloc tumor removal, the prostate and seminal vesical were resected completely. Finally, the vesicourethral anastomosis was performed by the urologist under the laparoscope. The patient was extubated and returned to the ward safely. The volume of intraoperative bleeding was about 600 mL. None of the blood products were infused perioperatively. The laboratory data revealed venous potassium level of 4.02, 3.91, and 3.90 mmol/L at postoperative days 1, 2, and 6, respectively. He was safely discharged 10 days later.

A similar event may occur in other kinds of minimally invasive surgeries, such as hysteroscopy.[ In the case of operative hysteroscopy, electrolytes abnormality may be induced by intravascular absorption syndrome due to an overload of low-viscosity fluids. However, there is some difference between these two cases. For most urologic surgeries, the urine output cannot always be well monitored. During laparoscopic prostatectomy (LP) or laparoscopic radical prostatectomy (LRP), urine tends to leak into the upper abdomen because of the patient's assumed 30° Trendelenburg position, especially, if the urine is not suction drained. Hyperkalemia occurred because the urine was mostly absorbed by peritoneum. Meanwhile, the arterial potassium level is always lower than that in the veins.[ An arterial potassium level of 5.8 mmol/L presented an extremely serious complication to the patient. Therefore, anesthesia providers must necessarily conduct ABG analysis to monitor the level of arterial potassium during LP or LRP.

Declaration of patient consent

The authors certify that they have obtained all necessary patient consent forms, stating that the patient has consented to the use of his clinical information for publication in the journal. The patient understands that his name and initials will not be published, and due efforts will be made to conceal the identity, but anonymity cannot be guaranteed.

Funding

This work was supported by a grant from the Six Talent Peaks Project in Jiangsu Province (No. 2015-WSW-020).

Conflicts of interest

None.