Anesthesia in Interventional Radiology

Introduction

IR Continues to Expand Rapidly

• IR has rapidly expanded its footprint and is now one of the most dynamic procedural specialties in modern medicine. IR encompasses a broad spectrum of image-guided interventions and therapies, including cardiac, vascular (arterial and venous), thoracic, musculoskeletal, and abdominal or organ-directed procedures.
• These procedures rely on various imaging modalities—most commonly fluoroscopy with ionizing radiation and iodinated contrast, but increasingly ultrasound and magnetic resonance imaging.
• The growth of IR has contributed substantially to the rise of NORA. Nationally, the proportion of anesthetics delivered outside the operating room (OR) continues to climb, approaching 50% of total anesthetic encounters in some practices.1 This shift underscores the need for anesthesiology professionals to be deeply integrated into IR workflows, ensuring safe, efficient, and high-quality care as the specialty continues to evolve.

Advancements in Procedural Technology

• IR has been described as the destination for patients “too sick for surgery.” While patient frailty remains a consideration, technological innovation is the primary driver of growth in IR anesthesiology today. Patients are offered IR procedures not solely because they are poor surgical candidates, but because these techniques provide superior recovery profiles, shorter hospital stays, and comparable or improved outcomes.²

Innovations in Interventional Oncology (IO) Procedures

• Percutaneous oncologic ablative therapies are commonplace for solid organ malignancies—such as lung, liver, renal, and prostate tumors— with often same-day or expedited discharge. Percutaneous hepatic perfusion (PHP) for metastatic uveal melanoma is an emerging IO therapy. PHP involves isolating the hepatic circulation, delivering high-dose melphalan, and filtering the blood through an extracorporeal circuit. Patients can develop profound but transient vasoplegia requiring high-dose vasopressors and require blood product transfusion. Despite this physiologic intensity, most patients are quickly stabilized, extubated at the end of the procedure, and discharged within 24 hours.⁵
• As IR case volume and procedural complexity continue to accelerate, anesthesiology teams must be prepared to meet the evolving demands of this environment. These challenges include caring for increasingly complex patients, navigating the physical and ergonomic hazards inherent to IR suites, and managing high-acuity physiologic perturbations and emergencies.

Patient Selection

• Two key factors drive anesthesiology patient care:

1. Predetermined exclusion criteria for moderate procedural sedation, which include severe cardiopulmonary frailty, chronic pain, and criteria determined by IR procedural leadership
2. Procedure factors, which include duration, complexity, and pain intensity

• Per the 2024 AHA/ACC guidelines on perioperative cardiovascular management of patients undergoing non-cardiac surgery, the majority of IR procedures are classified as low risk, with minimal hemodynamic and volume shifts.⁶
• For patients needing anesthesiology care, the main goals in evaluation are:
  • Patient risk stratification
    • Cardiac risk factors
    • Obstructive sleep apnea (OSA)
    • Neurocognitive risk stratification (should be considered for complex and long procedures)
  • Procedure designation
    • Elective vs non-elective
    • Urgency
  • Optimization
  • SDM

Risk Stratification

• Although no IR-specific tool exists, traditional surgical risk calculators can serve as a formal framework for risk assessment (Table 1).
  • OSA has been associated with adverse surgical outcomes for ambulatory surgery and can be added.

• • Neurocognitive risks: Baseline cognitive impairment, frailty, sensory impairment, malnutrition, and surgery duration are major predictors of delirium.
• Once risk has been assessed, the patient’s comorbidities should be optimized within a reasonable timeframe. For non-urgent, complex procedures, there may be a role for:
  • Multidisciplinary preoperative clinics to reduce cancellations
  • Prehabilitation (e.g., the PREHAB trial) has decreased complications by nearly 50% in colorectal surgery patients
• A significant number of high-risk patients presenting for IR procedures are categorized as non-elective and non-urgent, such as:
  • Cancer-related therapies
  • Inpatient procedures involving discharge to rehabilitation, such as percutaneous gastrostomy feeding tubes and tunneled lines for venous access and renal replacement therapy
  • Palliative procedures
• SDM is important in the care of very high-risk patients.²
  • SDM involves making joint medical decisions with the patient taking into account the patient’s understanding, wishes for goals of care, procedural risks and benefits, and alternatives
  • Provides patient agency leading to satisfying care decisions

High Risk Patient Selection Framework

• Below is the workflow for a high-risk patient.

Workflow and Environmental Considerations

• Occupational Hazards: A study by Piersa et al. found that most head strikes (948; 65.8%) occurred intraoperatively, with multifactorial causes often involving equipment placement, clinician movement, and time-sensitive actions, such as rapid responses during emergencies.³ In IR, it is important to note the presence of large mobile C-arms, overhead lead shields, and all monitors positioned at head height (Figure 2).

• Key prevention strategies include padding equipment edges, marking hazards with high-visibility tape, and standardizing equipment placement. Establish clear pathways for movement and require verbal callouts before repositioning imaging equipment. Incorporate spatial hazard assessment into procedural timeouts.
• Designate specific work zones with clear boundaries for anesthesiology professionals. Require team communication before moving any equipment, particularly during airway management, when rapid repositioning may be necessary.
• Radiation Safety: Preventing excessive radiation exposure in IR involves minimizing exposure time and using shielding, enforcing the use of lead aprons, thyroid shields, and lead glasses, and conducting thorough occupational exposure monitoring with dosimetry badges. Please see the OA summary on radiation safety for the anesthesia provider for more details. Link
• Scattered Radiation and High-Dose Fluoroscopy: The International Commission on Radiological Protection (ICRP) and the National Council on Radiation Protection & Measurements (NCRP) recommend maintaining a safe distance of at least 2 meters (approximately 6.5 feet) from the radiation source whenever possible.4 During high-dose fluoroscopy, maximize your distance from radiation sources when you can and use additional mobile lead shielding (Figure 3).

Emergencies in IR

• Blood transfusion: IR is frequently used to manage acute hemorrhage because it is minimally invasive and highly effective.
  • Staff training: Ongoing education on protocols and the importance of timely blood procurement can help prevent delays.
  • Quality improvement: Regular simulations and training in emergency response and blood management protocols can enhance team performance and ensure that all team members are prepared to respond promptly in hemorrhage situations.
• Airway Emergencies and Limited Access: Airway emergencies in IR are difficult due to confined spaces, overhead equipment, and sterile drapes that limit access to the patient’s head. Mobile C-arms, lead shields, and monitors must be moved rapidly, necessitating prompt communication and coordination.
  • Emergency procedures: Establish clear, rehearsed protocols with the IR team for rapid removal of obstructing equipment.
  • High-risk cases: For patients at high risk or undergoing prolonged deep sedation, consider prophylactic airway management (e.g., endotracheal intubation or supraglottic airway), as airway rescue is more challenging in this setting.
• Contrast Reactions and Anaphylaxis: Iodinated contrast use in IR carries risks from mild urticaria to life-threatening anaphylaxis.
  • Immediate management: Stop contrast administration, call for help, and ensure rapid access to emergency medications (epinephrine, antihistamines, corticosteroids, vasopressors).
  • Preparedness: Keep emergency medications immediately available in the procedure suite.
  • High-risk patients: For those with prior contrast reactions, consider premedication with corticosteroids and antihistamines, using non-iodinated contrast, or selecting alternative imaging modalities when feasible.
• Support staff availability: IR suites typically have fewer nurses and IR technicians with anesthesia experience than ORs.
  • Emergency preparedness: Clearly identify who can assist and know how to activate additional help, such as a rapid response team, extra anesthesia staff, or backup from OR personnel.
• Communication systems: Use established hospital devices, including landline phones, overhead paging, hospital-issued pagers, and intercoms, which reliably function throughout the IR suite.
  • Avoid personal devices: Cell service coverage varies, and IR suites often have dead zones or poor reception, which can cause critical delays in receiving assistance during emergencies.
• Non-OR anesthesia challenges include unfamiliar equipment, limited space, variable access to assistance, and distance from emergency resources.
  • Variable suite layouts: Unlike standardized ORs, each IR suite may vary, requiring familiarity with equipment placement, oxygen supply, suction access, and knowing the location of the code cart before emergencies.