Anesthetic Considerations for Outpatient Interventional Radiology Procedures for Cancer Patients

Abstract

Purpose of review:

Interventional radiology (IR) has emerged as a vital component of cancer care, offering minimally invasive procedures for diagnosis, therapy, and palliation. The increasing safety and efficacy of these procedures have led to a surge in their adoption, including in nonoperating room anesthesia and outpatient settings.

Recent findings:

Cancer patients increasingly present with complex medical histories for outpatient IR procedures and require specialized anesthetic care. The decision to perform an IR procedure in an outpatient setting should be based on careful evaluation of patient and procedure factors and facility resources, which varies among outpatient hospital settings, office-based labs, and ambulatory surgery centers. Oftentimes, oncology patients undergo repeated or multiple procedures at various points in their diagnostic and treatment course.

Summary:

We review the types of settings and cases and the patient selection and anesthetic considerations for outpatient IR procedures in cancer patients. By understanding the unique challenges posed by this patient population, including their increased comorbidity burden, potential treatment-related complications, and the need for tailored anesthetic techniques, anesthesia providers can optimize patient care and minimize perioperative risks.

Introduction

The prevalence of cancer diagnosis and survivorship is projected to grow, particularly in patients 65 years and older and with high comorbidity burden [1, 2]. Advancements in radiologic imaging and minimally invasive techniques within the field of interventional radiology (IR) have reduced cost, recovery times, and led to fewer complications compared to historical therapies [3*, 4]. By offering an innovative range of cancer therapies, interventional oncology (IO) has emerged as an important pillar of cancer care [5]. Oncology patients often undergo multiple procedures related to cancer diagnosis, therapy, and symptom palliation, supporting the longitudinal involvement of IO and IR in this population [4, 6*].

Cancer patients often present with complex medical histories and require specialized anesthetic care to ensure safe and effective procedures. Administration of anesthesia for general IR and IO procedures is typically classified as nonoperating room anesthesia (NORA) [7*]. The increasing demand for IR and IO procedures contribute to the growth of NORA [8, 9]. While IR procedures are generally performed in hospital locations, often located far from the main operating room (OR) area, some IR procedures may be performed in the outpatient setting due to the minimally invasive nature, safety profile, and short postoperative recovery [6*]. Additionally, procedures performed in the ambulatory setting offer improved efficiency and increased patient satisfaction, while freeing up hospital resources [10]. Outpatient settings like office-based labs (OBLs) and ambulatory surgery centers (ASCs) reduce patient wait times and cost compared to hospital-based settings [11*]. Carefully selected cancer patients can undergo anesthesia for same-day surgery and for repeated procedures with low anesthesia-related complications at freestanding ASCs [12*].

Patients who undergo radiology procedures in NORA locations have been noted to have higher American Society of Anesthesiologists (ASA) physical status (PS) scores and more complications compared to OR populations [13]. This is particularly true for cancer patients who experience complications from their disease or treatment [14*]. Furthermore, increasingly urgent and emergency procedures are being performed in medically unstable patients in ambulatory settings. Medically complex patients may undergo NORA procedures when invasive surgical procedures are no longer indicated or carry a higher risk [15].

We review the types of settings and cases and patient selection and anesthetic considerations for outpatient IR procedures in cancer patients. We also discuss unique challenges associated with this patient population, highlighting the importance of safety to ensure high-quality care in outpatient IR.

Types of Outpatient IR Settings

Outpatient IR procedures can be performed in a hospital, an ASC, or an OBL. The decision to perform an IR procedure in an outpatient setting should be based on careful evaluation of patient and procedure factors as well as facility resources (Figure 1). Outpatient settings offer increased efficiency with a more patient-centered approach, reducing cost and administrative overhead while offering care closer to home [6*, 11*]. A survey of 45 European centers found that a major obstacle to setting up or expanding ambulatory IR service is cost [16]. In the US, the growth of outpatient IR has been facilitated by venture capital, private equity, and management firms with private equity [11*].

Figure 1:

Algorithm for scheduling interventional radiology procedures at hospital and outpatient locations

The market for OBLs has been growing due to increased physician autonomy and opportunity to generate revenue at lower cost [17*]. OBL facilities are set up in physician offices and offer diagnostics and lower complexity procedures that do not require general anesthesia. They are usually less expensive to build, but they may not be suitable for medically complex patients or procedures whereas ASCs can accommodate both [18]. However, even OBLs have been expanding their spectrum of patients and procedures. In one study at an academic OBL site, the number and complexity of IR procedures increased between 2017 and 2020 with nearly tenfold increase in revenue [17*]. By bringing the OBLs to community settings, IR can provide more convenient locations and scheduling options, thereby reducing travel time and potential delays compared with hospital-based locations.

IR suites in an ASC can be free-standing or combined with surgical ORs. ASCs typically offer a wider range of procedures, including those requiring deeper sedation or even general anesthesia. IR procedures include cancer care therapies, kyphoplasty, or Y90 radioembolization. The IR suite integrated at a freestanding surgery center was discussed in detail by Barnett et al. [6*]. Their high-volume IR service was established to meet the growing demand for comprehensive outpatient cancer care. Wells et al. described the framework and the procedural throughput of IR day-case units in the United Kingdom [19].

Types of Outpatient Oncologic IR Cases

Many oncologic procedures are minimally invasive and have low complication risk and can therefore be performed in an outpatient hospital setting, an OBL, or an ASC. Procedural and patient risk must be considered for each case. A facility’s ability to do more advanced outpatient procedures, such as lung biopsy and kyphoplasty, would require consideration of the facility’s resources, available imaging equipment, and ability to handle postprocedural complications [6*].

Oncologic patients require IR procedures at various points in their treatment course. Figure 2 lists the types of IR procedures at different stages of cancer care. Common outpatient IR procedures include venous access insertion and removal, biopsies (e.g., liver, kidney, pelvic, bone, bone marrow, and soft tissue), genitourinary catheter procedures, tumor radioembolization, and peritoneal and pleural catheters placements [6*, 16]. Supplementary Table 1, Supplemental Digital Content 1, http://links.lww.com/COAN/A105 lists common outpatient procedures for cancer patients [4, 6*, 17*].

Figure 2:

Types of interventional radiology (IR) procedures at different stages of cancer care

Patient Selection Considerations for Outpatient IR Cases

Patient selection is critical to minimizing perioperative complications and maximizing patient access. In ambulatory surgery, patient selection guidelines vary based on the surgical procedure, patient comorbidities, and anesthetic requirements [20]. Some facilities utilize absolute exclusion criteria, such as ASA PS score, age, body mass index, or obstructive sleep apnea [21–24]. Expansion of ambulatory surgery to patients with an elevated comorbidity burden, including ASA PS 3 and 4 patients, is evolving [25]. Patients with ASA PS 3 with optimized stable comorbidities may undergo ambulatory surgery and patients with ASA PS 4 may undergo low-risk procedures under topical, local, or regional anesthesia [26]. While the ASA PS score characterizes the patient’s overall health and perioperative risk, it does not reveal clinical differences between a patient with cancer and a patient with a different systemic disease, like heart failure [27–29]. Patients with cancer often experience a sharp decline in physical health over the last few years of life [30]. The rapid decline increases the risk of complications for patients scheduled for ambulatory procedures.

Patients presenting for palliative procedures in the outpatient setting typically have a higher comorbidity burden [12*]. Although these patients may not be acceptable candidates for outpatient surgery, they may be acceptable candidates for minimally invasive IR procedures with minimal sedation. Outpatient cataract surgery for elderly and medically complex patients is in some ways parallel to outpatient oncologic IR procedures. Cataract surgery is an extremely low risk procedure and patients can receive safe anesthetic care with topical or regional anesthesia with or without minimal sedation in an outpatient setting [31]. There is a need for more published evidence establishing if procedural risk in outpatient minimally invasive IR procedures is comparable to the low risk associated with cataract surgery.

Preoperative testing for patients undergoing outpatient procedures, including IR as a referral service, is generally not indicated [20]. However, patients undergoing procedures with elevated complexity benefit from preprocedural consultation in the clinic and can be referred to an inpatient setting if the procedure is deemed not appropriate for the outpatient setting [17*, 32]. Preprocedural consultation is important to ensure that comorbidities, whether related to cancer or oncologic treatment, are optimized [14*]. Electronic preoperative surveys have been shown to improve preprocedural awareness and ensure that patients can safely undergo outpatient NORA procedures at their scheduled locations [33].

Patients may present with a Do Not Resuscitate (DNR) order in place, especially for palliative procedures. DNR orders should not be automatically reversed but instead prompt discussions in which the anesthesiologist asks patients about their wishes [34]. Patients should choose to temporarily suspend the DNR or keep it in place for the perioperative period.

Anesthetic Considerations for Outpatient IR Cases

Anesthesia techniques for IR cases range from local to general anesthesia and can include minimal, moderate, and deep sedation and regional anesthesia. Typically, local anesthetic injections are used by interventional radiologists with or without additional anesthesia. The decision to undergo monitored anesthesia care (MAC) by an anesthesia provider compared to minimal or moderate sedation by a sedation nurse or proceduralist is dependent upon the availability of staffing at the facility (e.g., presence of trained sedation nurses), the complexity of the procedure, the patient’s clinical condition, and the ability for the provider to optimize sedation level, control pain, and respond to the pathophysiology of the patient during the procedure. If there are safety concerns, including patients with signs of clinical instability (e.g., vital signs or laboratory values outside of the normal range), known small bowel obstruction, BMI over 45 kg/m², and chronic pain, then anesthesia care provided by an anesthesia provider should be considered over nurse sedation. If a patient requires conversion to a general or regional anesthetic, then MAC by an anesthesia provider allows for the safe administration of a depth of sedation that cannot be provided by proceduralist administered moderate sedation. Additionally, MAC by an anesthesia provider allows for the provision of the full extent of anesthesia services, including preprocedural assessment, support of hemodynamic stability and airway management given a patient’s comorbidities, ability to administer a full range of sedatives and analgesics as necessary, and postoperative medical and pain management [35]. Administration of MAC by an anesthesia provider compared to administration of moderate sedation by the IR sedation nurse under an IR physician’s supervision was associated with a small decrease in mean procedure room time. This suggests that involving an anesthesia team enhances IR procedure room efficiency by allowing the IR physician to focus solely on the procedure while sedation is provided efficiently and safely by the anesthesia provider [36*].

Outpatient IR procedures at an OBL or ASC are usually minimally painful and oftentimes can be performed with sedatives, including dexmedetomidine, ketamine, midazolam, propofol, and remimazolam, possibly in combination with a short-acting opioid (e.g., fentanyl) [6*]. Although propofol is commonly used for outpatient colonoscopies, a meta-analysis found that its use was associated with a higher rate of hypotension compared to other sedatives, including midazolam and remimazolam. The study also reported that dexmedetomidine had an even higher rate of hypotension than propofol [37]. In another meta-analysis, dexmedetomidine was associated with a lower incidence of amnesia and respiratory effects but had a longer time to recovery and a higher incidence of hypotension and bradycardia in NORA procedures in adults [38].

Remimazolam is an ultra-short acting benzodiazepine approved for patients undergoing sedation for procedures 30 minutes or less [39]. It is less likely to cause cardiopulmonary depression than propofol and therefore preferred in older and medically complex patients who are unable to tolerate propofol sedation, including patients with significant aortic stenosis and other significant cardiopulmonary comorbidities [40*, 41*, 42]. Remimazolam is a feasible option as the sole anesthetic agent in IR procedures, as noted in a case series of radiographically placed gastrostomy tubes [43]. Remimazolam availability is often limited due to its higher cost compared to other common sedatives.

Either propofol or remimazolam are preferred due to the rapid awakening to facilitate discharge in an outpatient setting. The slower wake up with ketamine and dexmedetomidine are less desirable in a quick outpatient setting. The specific anesthetic management varies depending on several factors, such as the cost of medications, anesthesia personnel, complications, and recovery. Relevant anesthetic considerations of sedatives routinely used in outpatient IR procedures are listed in Table 1 [39, 44–46].

Table 1:

Anesthetic considerations of sedatives for outpatient interventional radiology procedures [38, 43–45]

Characteristic	Dexmedetomidine	Ketamine	Midazolam	Propofol	Remimazolam
Low cardiac depression risk		✔	✔		✔
Low respiratory depression risk	✔	✔	✔		✔
Rapid onset of action		✔		✔	✔
Rapid postoperative recovery				✔	✔
Reversal agent available			✔		✔
Analgesic effect	✔	✔
Anxiolytic effect	✔	✔	✔	At low doses	✔
Active metabolite		✔	✔
Metabolism	Hepatic	Hepatic	Hepatic	Hepatic & extrahepatic	Tissue esterases
Ready to use	Dilution	✔	✔	✔	Reconstitution

Studies examining the effects of perioperative anesthetic techniques, including opioids, regional anesthesia, and lidocaine, on long-term oncologic outcomes, including cancer recurrence, have not conclusively identified any causal relationships. However, prospective randomized control trials are ongoing to establish if anesthetic or analgesic techniques influence cancer recurrence [14*, 47*].

Challenges of Oncologic Patient Undergoing Anesthesia for Outpatient IR

Oncologic patients may be cachectic, frail, or present with different organ toxicities secondary to chemotherapy, radiotherapy, or immunotherapy that may interfere with perioperative care (Figure 3) [10, 48]. Chemotherapy affects several different organ systems, including the cardiovascular, pulmonary, renal, and hepatic systems. Patients undergoing active treatment often have immunosuppression with neutropenia, increasing the risk of infection. Alternatively, patients may experience a proinflammatory response, increasing the risk of thrombosis. Cardiovascular damage may occur from several different chemotherapeutic agents, including anthracycline-induced cardiotoxicity, 5-fluorouracil-induced myocardial ischemia, and arrythmias from anthracyclines and cisplatin. Patients may experience pulmonary toxicity, including pulmonary fibrosis from bleomycin and alkylating agents and interstitial pneumonitis from mitomycin C and gemcitabine. Cisplatin may cause acute renal injury and multiple agents, including oxaliplatin and 5-fluorouracil, may cause hepatic toxicity. Peripheral neuropathy is a common side effect of several chemotherapeutic agents. Central neuropathy may also occur, including encephalopathy, autonomic dysfunction, and progressive dementia [48, 49].

Figure 3:

Preoperative considerations specific for outpatient oncologic interventional radiology patients

Immunotherapy is increasingly employed for cancer treatment and is more likely to cause immune-related adverse reactions in any organ system. Examples of reactions include endocrinopathies (e.g., adrenal insufficiency, hypothyroidism), myocarditis, pericarditis, pneumonitis, gastritis, and hepatitis [48, 50].

Radiation often has a pro-inflammatory effect, causing organ and vascular damage in the area that was irradiated. This is especially pertinent for patients who underwent head and neck radiation, which can lead to airway management difficulties [48].

A focused history and physical exam are needed to assess comorbidities and symptoms related and unrelated to cancer and cancer treatment [14*, 49]. Hypertension, chronic obstructive pulmonary disease, and diabetes were the most prevalent comorbidities present at diagnosis based on a cohort study of four cancers [51]. Laboratory studies may be required either due to procedural requirements or because of potential treatment toxicities. For example, hypokalemia and hypomagnesemia may occur with a number of chemotherapy agents, such as cisplatin and cetuximab [52]. Concerns for immunotherapy-related toxicity often require additional laboratory testing not typically ordered prior to a procedure (e.g., thyroid and adrenal function testing). Patients can also be prescribed steroids for management of immunotherapy side effects [49]. However, intraoperative dexamethasone should be avoided in patients who have received recent chimeric antigen receptor T-cell treatments or have a known lymphoproliferative disorder, which increases the risk for tumor lysis syndrome [53, 54]. A complete blood count may be warranted to assess red blood cells, platelets, and white blood cell counts. If a procedure is being performed during chemotherapy, the white blood cells may nadir between 7 and 12 days after the patient’s last treatment, putting them at possible risk for infection [55].

Patients may be advised to wait 4 to 6 weeks between neoadjuvant therapy and surgery to allow for recovery from cytotoxic adverse effects [48]. However, in some cases, patients require urgent IR procedures, including vascular access placement or diagnostic biopsies.

Safety

As NORA, particularly IR, continues to grow, it is important to prioritize designing these anesthetizing locations with safety in mind [56**]. The organizational structure and clinical protocol of an ASC should involve close collaboration between the anesthesia and IR teams [6*]. If a patient requires hospital transfer from an outpatient setting for higher-level care, an established relationship should facilitate collaboration between IR physicians at both locations.

To ensure patient safety, standard monitors per the ASA guidelines should be employed [57]. The ASA Statement on NORA Services provides a framework of safety, design, and regulatory recommendations, including IR procedures (Supplementary Figure 1, Supplemental Digital Content 1, http://links.lww.com/COAN/A105) [58**]. The ASA Statement stresses that NORA locations should provide high quality of care, similar to that of traditional ORs.

A limited number of studies have evaluated the risk of adverse events in IR. Woodward et al. found that IR had a higher proportion of malpractice claims, most commonly due to respiratory complications and substandard monitoring, in patients who received general anesthesia compared to MAC [59]. Chang et al. reported that IR had a higher mortality rate compared to those undergoing surgery in the main OR, while also caring for a higher proportion of patients with ASA PS 3 and 4 [13]. While research on outpatient IR remains limited, a study of 135,285 outpatient IR cases by the Veterans Health Administration found that 0.18% of elective outpatient IR procedures were flagged with adverse events (admission, emergency visit, or mortality) within 14 days [60*]. With the growth of IR procedures performed in medically complex patients in the outpatient setting, refined quality and safety assurance metrics are likely to emerge.

Conclusion

Outpatient IR procedures offer benefits such as reduced costs, faster recovery, and improved patient satisfaction compared to inpatient procedures. OBLs and ASCs play a crucial role in expanding access for minimally invasive treatments, allowing for greater convenience and efficiency. However, careful patient selection and appropriate facility resources and anesthesia care plans, as well as adherence to safety guidelines are essential for ensuring optimal outcomes. Ongoing research and collaboration among stakeholders will be vital to further optimize the provision of anesthesia for outpatient IR services for cancer patients.

Key Points.

• Minimally invasive oncologic interventional oncology procedures with anesthesia services can be performed in an outpatient setting for diagnostic, therapeutic, or palliative purposes.

• Appropriate consideration of patient and procedure selection and facility resources are essential for the provision of safe and effective outpatient IR in cancer patients.

• Choice of sedation medications for outpatient interventional radiology procedures is based on cardiac and respiratory depression risk, rapidity of action and postoperative recovery, and need for analgesia or anxiolysis.

• Remimazolam is a new sedative that could be administered for short outpatient interventional oncology procedures, especially in older patients and patients with high comorbidity burden.

• Adherence to established safety guidelines, such as those outlined in the ASA Statement on NORA Services, is crucial to minimize risks and ensure high-quality care in outpatient IR settings.