Sudden cardiovascular collapse during the TUL procedure: A case series

Abstract

Although ureteroscopy is a minimally invasive procedure, there have been reports of some minor and major complications, from self-limited to complicated events such as ureteral avulsion, urosepsis, and even death due to cerebrovascular accidents and deep vein thrombosis. Herein, we aim to report seven patients who presented with cardiovascular collapse during ureteroscopy in a 19-year period from January 2002 to January 2021.

Introduction

Ureteroscopic (URS) interventions as minimally invasive procedures have gained wide acceptance and are among the most commonly performed procedures in urology, both diagnostically and therapeutically. Some population-based investigations have shown a dramatic increase in the prevalence of these procedures in recent decades.^1,2 Ordon et al. showed a significant rise in the use of URS, from 25% to 59% of all procedures, in a 9-year period in the province of Ontario, Canada. ¹ In another investigation, Turney et al. revealed a 127% increase in the number of URS performed over 10 years, from 2000 to 2010, in the UK. ³

Although ureteroscopy has been known as an effective, safe, and minimally invasive procedure, there have been reports of some minor and major complications, from self-limited, more commonly occurring conditions like ureteral wall injury, ureteral stent discomfort, and proximal stone migration to rare and more complicated events such as ureteral avulsion, urosepsis, and even death due to cerebrovascular accident and deep vein thrombosis.^4–6

In this case series, we will report seven patients who presented with cardiovascular collapse during the surgical procedure, all happening in university-affiliated or private hospitals in Shiraz, Iran, in a 19-year period from 2002 to 2021.

Methods and materials

This study was conducted from January 2002 to January 2021 in the operating room of Labbafinejad Hospital affiliated hospital of Shahid Beheshti University of Medical Science and Faghihi Hospital, affiliated hospital of Shiraz University of Medical Science, involving seven patients. All patients were interviewed, and informed consent was obtained, as this constituted a partial aspect of their diagnosis and treatment.

Case 1

In this case study, a previously healthy 20-year-old male patient with a Body Mass Index (BMI) of 24.2 underwent transurethral lithotripsy (TUL) for a left ureteral stone. The patient received premedication with diazepam and morphine sulfate, followed by induction of anesthesia with sodium thiopental. Anesthesia was maintained using 1% halothane in a 50:50 mixture of O2 and N2O. During the procedure, the patient experienced a rapid decline in arterial oxygen saturation despite interventions, ultimately leading to hypoxemia and ventricular fibrillation. Despite resuscitation efforts, the patient’s condition deteriorated, leading to pulmonary edema, hypotension, and fixed, dilated pupils. Subsequent management of pulmonary edema proved partially effective, but the patient’s status worsened, leading to prolonged hypoxemia and ischemic brain damage, resulting in eventual demise. This tragic case highlights the complexities and challenges associated with managing anesthesia-related complications and their potential impact on patient outcomes.

Case 2

A 36-year-old male patient (BMI 23) with no underlying disease underwent TUL for the removal of his right distal ureteral stone. Baseline vital signs were: PR 68 bpm, BP 110/80 mmHg, and arterial oxygen saturation 100%. After preoxygenation with 100% oxygen, midazolam (3 mg) and morphine (5 mg) were injected as premedication. Anesthesia and muscle relaxation were induced with sodium thiopental (300 mg) and pancuronium (6 mg), respectively, and after tracheal intubation, they were maintained by O₂:N₂O (50:50) and Isoflurane. About 45 min after induction, the patient presented with low oxygen saturation, an end-tidal carbon dioxide (ETCO2) drop, bradycardia, and a sudden cardiovascular collapse. He also developed cyanosis all over his upper torso, head, and neck. Cardiopulmonary resuscitation (CPR) was started immediately and lasted for about the next 1.5 h until the circulation was restored, but he died a few hours later in the intensive care unit (ICU) (there was not much additional information in his hospital chart; we are just sure that the same irrigation set was applied during the procedure).

Case 3

A healthy 30-year-old woman (BMI 22.6) underwent TUL for a distal ureteral stone. Following induction with midazolam, morphine, fentanyl, and propofol, anesthesia was maintained using propofol, remifentanil, and a 50% O2-N2O mixture. During cystoscopy, sudden cyanosis, oxygen saturation drop, and end-tidal CO2 decrease led to procedure cessation. Intubation, ventilation, and resuscitation with epinephrine, chest compression, and central vein catheterization were executed. Chest tubes were inserted, revealing blood and effusion. A subsequent thoracotomy exposed pericardial fluid. Despite intensive efforts, CPR was ineffective. Autopsy identified pulmonary edema, lung congestion, suggesting a suspected massive air embolism as a potential cause of this tragic outcome.

Case 4

This case study presents a 54-year-old obese woman (BMI 30.6) with no comorbidities, undergoing an emergency TUL for bilateral ureteral stones. Initially, her vital signs were stable (blood pressure (BP) = 140/80 mmHg, pulse rate (PR) = 70 bpm, SaO2 99%). General anesthesia involved midazolam, fentanyl, sodium thiopental, atracurium, propofol, and a 50:50 oxygen-nitrous oxide mixture. During the procedure, her oxygen saturation decreased to 88%, recovering to 92% with escalated fraction of inspired oxygen (FiO2) and positive end-expiratory pressure (PEEP). At surgery’s end, a sudden drop in SaO2, PR, ETCO2, and blood pressure led to asystole. CPR was initiated, with subsequent low oxygen saturation and pulmonary edema. Autopsy findings exhibited consolidated lungs with bloody-foamy secretions and mild leukocyte infiltration, but no cardiac abnormalities. Despite resuscitation efforts, the patient experienced recurrent cardiac arrests and passed away. This case underscores the complexity of perioperative management and underscores the challenges in addressing acute respiratory and cardiovascular events in high-risk patients undergoing emergent procedures.

Case 5

This case study outlines a 52-year-old, healthy male (BMI 26.2) who presented with fever, headache, and nausea. Urgent TUL was undertaken for a left ureteral stone diagnosis. Baseline vital signs indicated PR 97 bpm, BP 135/80 mmHg, and O2 saturation 99%. Preoxygenation with 100% O2 preceded premedication using midazolam, fentanyl, and morphine. Anesthesia induction featured propofol and cisatracurium, with maintenance involving a 50% O2, 50% nitrous oxide, and isoflurane combination. During the procedure, an empty irrigation bottle prompted a sudden decline in SaO2 to 75%, BP to 90/70 mmHg, and ETCO2 to 21 mmHg. Patient positioning and manual ventilation elevated saturation to 93%, yet it regressed to 84%. Emergency cardiology consultation resulted in electrocardiogram and bedside transthoracic echocardiogram, both revealing normal cardiac parameters. Stabilized, the patient was extubated and moved to recovery. Post-Anesthesia Care Unit (PACU) admission saw hypoxemia (SaO2 75%) and hypotension (BP 77/65 mmHg), mandating intubation and dopamine infusion. ICU transfer was pursued, concluding in urosepsis-related demise after a prolonged stay. This case underscores the intricate interplay of anesthesia, resuscitative interventions, and urosepsis management in emergent scenarios.

Case 6

A 42-year-old male (BMI 34.7) with a history of grade 2 fatty liver underwent TUL for a left distal ureteral stone. General anesthesia induction used sodium thiopental, atracurium, and maintenance employed isoflurane in a 50:50 oxygen-nitrous oxide mix. During the procedure, sudden bradycardia, severe hypoxemia (SaO2 70%), hypotension, and low ETCO2 (15–20 mmHg) emerged, coupled with cyanosis above the umbilicus. Despite initial normal lung sounds, peripheral pulses weakened, leading to electromechanical dissociation. CPR commenced, yet a central venous pressure (CVP) catheter insertion yielded no air aspiration. Despite cardiopulmonary bypass and ICU care, subsequent evaluation unveiled ischemic brain damage. Autopsy findings disclosed congested lungs, alveolar collapse, myocardial ischemia, and cerebral edema. This case highlights an intraoperative crisis with profound hypoxemia, cardiovascular collapse, and multisystem involvement, underscoring the intricate challenges in management and the ensuing adverse outcomes.

Case 7

A 50-year-old male (BMI 25.8), with a history of hyperlipidemia, underwent TUL for left ureteral stone removal. Baseline vitals were BP 120/80 mmHg, PR 91 bpm, SaO2 98%. Prehydration and preoxygenation preceded midazolam, morphine, fentanyl administration. Anesthesia induction used propofol, maintained with 50% O2, 50% N2O (via laryngeal mask airway), and propofol. The procedure began lithotomy position with irrigation via “compression set.” Within 15 min, severe hypotension (55/30 mmHg), desaturation (84%), bradycardia (50 bpm) arose. Intubation, correct tube placement, and chest excursion didn’t improve saturation or BP. Central vein catheterization drained air bubbles and foamy blood, epinephrine and heparin infusions commenced. Oxygen saturation fell to 75%, precipitating cardiovascular collapse and cardiac arrest. CPR led to recovery (BP 99/45 mmHg, SaO2 100%, PR 110 bpm). Post-ICU transfer, the patient recovered without lasting sequelae. This case underscores the challenges in managing intraoperative crises, highlighting prompt intervention’s potential for favorable outcomes.

Discussion

Traditionally, venous air embolism (VEA) has been known to occur in clinical scenarios in which the surgical field is above the heart level, where there will be a tendency for air to be sucked into the vasculature through an open vein or venous sinuses. Minimal procedures like central vein catheterization, ⁷ pleural pigtail chest tube insertion, ⁸ and surgeries like posterior fossa procedures in the sitting position ⁹ and those with cardiopulmonary bypass, ¹⁰ though rarely reported, have been associated with this fatal complication. In the modern era of surgery, techniques involved with gas insufflation, for example, shoulder arthroscopy ¹¹ and laparoscopic surgeries, ¹² have been shown to expose patients to this complication. Literature shows the occurrence of venous air embolism even when the fluid has been used as the medium to expand or irrigate the surgical field.^13,14 As in the case of negative pressure, which draws air into the circulation, positive insufflation of the air or air-fluid mixture into the body cavities may end up with the appearance of air bubbles in the bloodstream. ¹⁵

The morbidity and mortality of the event are the products of both the volume and rate of air entrainment into the circulation. Although the exact lethal dose of air is still not clear, evidence shows that as much as 200–300 ml could be problematic. ¹⁵ Unless expected and special monitoring devices are being used, a definite diagnosis would be challenging, and it would be a matter of ruling out other possible causes since the air in the vasculature may leave no trace at all at the autopsy. In almost all of the above cases, the patients had no serious medical issues, and they were all in good health status with acceptable functional capacity. The timing of the events leaves little room for accepting the drug hypersensitivity reaction as the diagnosis, at least in its acute presentation, since they occurred near the end of the surgical procedure. At least in one case (no. 7), in which a central vein was cannulated rapidly, a significant amount of air was aspirated, and the patient regained his normal circulation and survived. No obvious cause for the patient’s sudden cardiovascular collapse was detected in the autopsy reports.

The aforementioned “irrigation set,” despite the claim of its safety, seems to be an unstandardized and uncontrolled device regarding the pressure it generates and, consequently, the amount of air that it delivers. ¹⁶ Even though there are no visible air bubbles in the connecting tubes, the irrigation fluid may contain a large amount of dissolved air under pressure, which has the potential to form bubbles as it reaches the higher temperature and lower pressure milieu of the pelvicalyceal system and circulation, according to the law of physics (Henry’s law).

In 2004, Frasco et al. reported a case of VAE during transurethral resection of the prostate in an 80-year-old patient. The wrong assembly of the irrigation pump was claimed to be the cause that forced a significant amount of air into the patient’s bladder. ¹⁴ There are also a few reports of air getting into the venous system during the percutaneous nephrolithotomy procedure, mostly during the air pyelogram phase,^17–19 or during the retrograde intrarenal surgery. ²⁰ In the latter report, the authors attributed this complication to the lower ureteral positioning of the access sheath, which may result in a rising pressure in the renal pelvis, and also to air bubbles mixed with the irrigation saline or produced during the laser lithotripsy. These clinical reports reveal that the forced air, with or without fluid, in the pelvicalyceal system may somehow gain entry into the venous system, even though the small vascular openings made during the procedure.

In all cases in this series, the anesthesiologists confronted an almost similar scenario in a young to middle-aged patient without any serious comorbidity: a sudden drop in oxygen saturation and end-tidal CO₂, accompanied by severe hypotension and vascular collapse, all common features of the embolic phenomenon. In some of them, the patient’s internal jugular vein was cannulated, finally and with some delay after the initiation of CPR and chest compression, a maneuver that can dissipate, disperse, and move the large air bubbles into the pulmonary vasculature, except in the last case (no. 7), which did not receive any chest compression. Postmortem pathologic reports were all inconclusive.

Conclusion

Venous air embolism can be considered a rare but sometimes disastrous complication of the ureteroscopic procedures in endourology, for which the medical team should be prepared to deal with and manage it properly. The issue brings up the necessity of using more standard and sophisticated devices and paying meticulous attention to the assembly and setup.