INTRODUCTION — Advanced technology and imaging techniques have resulted in development of interventional radiology (IR) procedures for medical conditions and injuries that once required treatment in an operating room setting. Thus, there is an increasing need for anesthetic care in IR suites for patients who require complex or prolonged procedures and often have significant comorbidities. This setting also poses challenges in anesthetic care due to its "off-site" location remote from the main operating room area, which necessitates special preparations.

This topic will review common concerns regarding anesthetic management of patients undergoing procedures in the IR suite. Details regarding anesthetic management of patients undergoing specific types of endovascular procedures in an IR suite are reviewed separately:

●(See "Anesthesia for endovascular therapy for acute ischemic stroke in adults".)

●(See "Anesthesia for intracranial neurovascular procedures in adults".)

●(See "Anesthesia for endovascular aortic repair".)

Patients undergoing other types of diagnostic radiology procedures (eg, magnetic resonance imaging [MRI], computed tomography [CT]) occasionally require anesthetic care; considerations are reviewed separately. (See "Anesthesia for magnetic resonance imaging and computed tomography procedures".)

PREPROCEDURE CONSIDERATIONS

Overview of challenges

●Location of the interventional radiology suite – Many interventional radiology (IR) suites are located distant from the main operating room area and are not designed for delivery of anesthetic care. Thus, it is necessary to transport all anesthetic equipment and drugs to such IR suite locations. Placement of the anesthesia workstation and drug cart within the suite is usually suboptimal when there is no specific space allocated for the anesthesia workstation and drug cart, and positioning of the patient and anesthetic equipment in relation to the radiology equipment may not allow easy access by the anesthesia provider.

●Provider exposure to radiation – The anesthesia provider may be exposed to ionizing radiation during adjustments of doses of anesthetic agents or troubleshooting monitoring equipment. Radiation dose is determined by duration of exposure time, distance from the radiation source, and whether shields are used. Generally, the anesthesiologist should stand as far away as possible from the source of radiation, while still providing safe patient care. Whenever possible, the anesthesiologist should stand behind a portable shield and wear suitable shielding equipment (ie, lead aprons, thyroid collars, eye protection) [1,2]. (See "Radiation-related risks of imaging".)

●Unfamiliar personnel – Personnel working in the IR suite may not be familiar with anesthetic care, particularly anesthesia-related emergencies. Strategies to manage emergencies in off-site locations include:

•Placement of resuscitative equipment that might be needed for a high-risk patient in the immediate vicinity of the IR suite (eg, difficult airway cart, invasive monitoring equipment).

•Ready availability of cognitive aids for specific emergency situations, particularly if radiology personnel in off-site locations only rarely participate in crisis management for anesthesia-related emergencies [3]. (See "Cognitive aids for perioperative emergencies".)

•Prearranged communication protocols with anesthesiology and other specialized personnel outside the IR suite to ensure rapid response to an emergency call for assistance. (See "Anesthesia for magnetic resonance imaging and computed tomography procedures", section on 'Communication'.)

Preparation of anesthetic equipment — The American Society of Anesthesiologists (ASA) has provided recommendations for management of patients receiving anesthesia care in off-site locations that are remote from the main operating room [4]. Similar to preparation for anesthetic care in magnetic resonance imaging (MRI) or computed tomography (CT) imaging suites [3], preparation for IR procedures typically requires extra time to complete the following tasks (see "Anesthesia for magnetic resonance imaging and computed tomography procedures", section on 'Preparation'):

●Transporting monitors and equipment, as well as anesthetic agents and other drugs, to the remote location

●Positioning the anesthesia workstation so that the anesthesiologist will be able to view both the patient and the anesthesia monitors, either by direct observation or on a video monitor

●Setting up extension tubing for intravenous lines, as well as having circuit extenders for the anesthesia machine to facilitate ventilation and monitoring respiratory gases (eg, end-tidal carbon dioxide [EtCO₂], expired inhaled anesthetic concentrations)

●Establishing familiarity with anesthesia machines and other equipment, which may differ from those typically used in the main operating room

Preanesthesia patient evaluation — The interventional team typically consults anesthesia personnel to determine what type of anesthetic care is recommended, particularly for concerns such as severe patient pain or anxiety, inability to lie supine, inability to cooperate, class II obesity, a difficult airway, obtunded or comatose state, or hemodynamic instability. The anesthesiologist reviews the pathology for which the procedure is being performed, the interventionalist's specific requirements for completion of the procedure, and patient comorbidities. Also, women of childbearing age are assessed for the possibility of pregnancy. Goals of this preanesthetic evaluation include reducing modifiable risk factors while minimizing costs. (See "Preanesthesia evaluation for noncardiac surgery".)

Patients undergoing IR procedures are typically receiving care from a different in-hospital service or are referred for the procedure from an outside practitioner. Thus, the anesthesiologist often serves as a liaison between the interventionalist and the referring clinician (primary care clinician and/or other specialists) during the pre-procedure period. In this role, the anesthesiologist ensures that pre-procedure patient status is optimal, special preparations have been made for any patient-specific issues, and patient education regarding periprocedural expectations has been accomplished. (See 'Clinical vignettes' below.)

ANESTHETIC TECHNIQUES — Selection of an anesthetic technique (ie, monitored anesthesia care [MAC] with minimal or deep sedation, regional or neuraxial anesthesia, or general anesthesia) depends on procedure-specific and patient-specific consideration [5,6]:

●Procedure-specific factors

•Type of procedure

•Anticipated duration and complexity of the procedure

•Need for uncomfortable or unconventional patient positioning

•Requirement for absence of movement or intermittent apnea

•Patient and anesthesia team exposure to radiation

●Patient-specific factors

•Hemodynamic instability

•Altered level of consciousness with risk for aspiration or unwanted patient movement

•Inability to cooperate for other reasons (eg, chronic or acute pain, severe anxiety)

•Inability to lie supine

•History of difficult airway

•Obstructive sleep apnea or class II obesity

•Patient preferences

These considerations are similar to those for magnetic resonance imaging (MRI) or computed tomography (CT) imaging procedures. (See "Anesthesia for magnetic resonance imaging and computed tomography procedures", section on 'Anesthetic techniques'.)

Many interventional radiology (IR) procedures can be accomplished with conscious sedation (ie, MAC). Deep sedation can easily become general anesthesia, especially if propofol is administered (table 1) [7]. Moderate sedation refers to a level of sedation in which patients respond purposefully to verbal commands and maintain spontaneous ventilation without support. Patients under deep sedation cannot be easily aroused, but respond purposefully to painful stimulation, and may require assistance in maintaining a patent airway. Regardless of the planned anesthetic technique, the anesthesiologist should always be prepared to induce general anesthesia if necessary.

CONSIDERATIONS FOR SPECIFIC PROCEDURES — Anesthetic considerations and potential complications differ for specific procedures performed in the interventional radiology (IR) suite.

Neurologic procedures — Neurologic IR procedures include emergency and elective intracranial or spine interventions.

Intracranial interventions — Preanesthetic assessment and intraoperative management of patients with intracranial pathology may be complicated by the patient's altered mental status and the need for urgent or emergency surgery. A focused and concise evaluation for emergencies (eg, acute ischemic stroke, ruptured intracranial aneurysm) emphasizes the basic neurologic examination (ie, level of consciousness, presence of neurologic deficits) and assessment of cardiovascular comorbidities including baseline blood pressure (BP) [8,9].

Specific intracranial endovascular interventions include:

●Emergency endovascular therapy for acute ischemic stroke [9]. (See "Anesthesia for endovascular therapy for acute ischemic stroke in adults".)

●Endovascular embolization of ruptured or unruptured intracranial aneurysms. (See "Anesthesia for intracranial neurovascular procedures in adults", section on 'Endovascular therapy for intracranial aneurysm'.)

●Endovascular embolization for brain arteriovenous malformations or fistulas, dural arteriovenous fistulas, or lymphatic malformations. (See "Anesthesia for intracranial neurovascular procedures in adults", section on 'Embolization for brain arteriovenous malformation'.)

●Intracranial angioplasty or stenting for large vessel lesions or vasospasm. (See "Anesthesia for intracranial neurovascular procedures in adults", section on 'Anesthesia for vasospasm treatment' and "Intracranial large artery atherosclerosis: Treatment and prognosis".)

●Intracranial venous stenting (pseudotumor cerebri) or thrombectomy (cerebral venous thrombosis, dural sinus stenosis). (See "Idiopathic intracranial hypertension (pseudotumor cerebri): Prognosis and treatment", section on 'Venous sinus stenting' and "Cerebral venous thrombosis: Treatment and prognosis", section on 'Endovascular treatment' and "Septic dural sinus thrombosis".)

●Endovascular intervention for blunt cerebrovascular injury. (See "Blunt cerebrovascular injury: Treatment and outcomes".)

Spinal interventions — Selection of anesthetic technique is individualized on a case-by-case basis depending on the interventionalist's requirements and patient preferences. Conscious sedation (ie, monitored anesthesia care [MAC]) is often sufficient for biopsies or interventional pain procedures.

In rare cases, somatosensory or motor evoked potentials may be monitored during interventions on the spine in the IR suite to prevent neural injury [10]. Anesthetic management for cases requiring such neuromonitoring is discussed separately. (See "Neuromonitoring in surgery and anesthesia".)

Many IR procedures for the spine are for cancer-related pathology. Such patients may be at the end of life, with considerations similar to those discussed below for palliative gastrostomy tube placement. (See 'Gastrostomy tube placement' below.)

Specific spinal interventional procedures include:

●Spine biopsy for impending or complete pathologic fracture in a patient with a solitary bone lesion, with or without a history of cancer. (See "Clinical presentation and evaluation of complete and impending pathologic fractures in patients with metastatic bone disease, multiple myeloma, and lymphoma", section on 'Diagnostic biopsy'.)

●Vertebroplasty, kyphoplasty, or spinal instrumentation for patients with pathologic spine fractures secondary to metastatic disease. General anesthesia is often selected because these procedures are performed in the prone position with limited access to the patients' airway, are painful, and require immobility to minimize risk of damage to surrounding structures. However, kyphoplasty can be completed in selected patients with MAC and sedation, with administration of an additional intravenous bolus dose of a sedative-hypnotic and/or analgesic agent before painful cement injections.

Additional information regarding these procedures can be found in the following topics:

•(See "Overview of therapeutic approaches for adult patients with bone metastasis from solid tumors", section on 'Vertebroplasty and kyphoplasty'.)

•(See "Treatment and prognosis of neoplastic epidural spinal cord compression", section on 'Role of vertebroplasty, kyphoplasty, and percutaneous spinal instrumentation'.)

•(See "Management of complete and impending pathologic fractures in patients with metastatic bone disease, multiple myeloma, and lymphoma", section on 'Vertebral augmentation procedures'.)

●Radiofrequency ablation (RFA) – RFA may be an alternative to surgical intervention for epidural spinal cord compression related to vertebral metastases in selected patients. (See "Image-guided ablation of skeletal metastases", section on 'Radiofrequency ablation'.)

●Other techniques for treatment of bone lesions – Other palliative or curative treatments for benign or malignant spine lesions that may be performed in the IR suite include cryotherapy, microwave ablation, laser ablation, and high-frequency intensity ultrasound [10]. In some cases, embolization of the arterial supply of a bony lesion may be employed. (See "Image-guided ablation of skeletal metastases", section on 'Techniques'.)

●Neuraxial techniques for chronic or cancer-related pain management

•Implantation of spinal cord neurostimulators – Spinal cord stimulation (ie, dorsal column stimulation) is a neuromodulation technique used to treat neuropathic and sympathetically mediated chronic pain. Electrodes are implanted in the epidural space using a percutaneous or open surgical technique, and a battery is implanted to supply power. Details regarding the procedure are available in other topics. (See "Spinal cord stimulation: Placement and management" and "Cancer pain management: Interventional therapies", section on 'Spinal cord stimulation'.)

•Neuraxial infusion – Continuous infusion of medications into the epidural or intrathecal space for targeted drug delivery is an option occasionally employed for patients with cancer-related pain refractory to systemic pharmacotherapy. (See "Cancer pain management: Interventional therapies", section on 'Neuraxial infusion'.)

Procedures for hepatic pathology — Patients with significant liver disease may undergo procedures in the IR suite; preoperative evaluation of these patients is discussed in a separate topic. Notably, pharmacokinetics and pharmacodynamics of most anesthetic drugs are altered in patients with significant liver disease [11]. (See "Anesthesia for the patient with liver disease", section on 'Preoperative evaluation and optimization' and "Anesthesia for the patient with liver disease", section on 'Effects of liver disease on anesthetic drug administration'.)

Transjugular intrahepatic portosystemic shunt procedures — Transjugular intrahepatic portosystemic shunt (TIPS) procedures are performed in patients with portal hypertension who have significant hepatic dysfunction after failed medical therapy [12,13]. The TIPS procedure involves creating a shunt between the hepatic and portal veins, which decompresses the portal circulation, thereby reducing portal hypertension and the associated risks of bleeding from esophageal varices or ascites formation. (See "Overview of transjugular intrahepatic portosystemic shunts (TIPS)".)

Either conscious sedation (ie, MAC) or general anesthesia can be used, but the latter is often preferred in patients with hepatic encephalopathy or ascites with associated risk of aspiration, or if a prolonged procedure duration is anticipated. Potential complications of TIPS procedures include vascular injury, dysrhythmias, hemorrhage from catheter insertion, and pneumothorax. (See "Transjugular intrahepatic portosystemic shunts: Postprocedure care and complications".)

Procedures for treatment of hepatic tumors — Selected procedures to treat hepatic tumors are performed in the IR suite. These include radiofrequency ablation or cryoablation, as well as embolization of the vascular supply to large tumors in selected cases (eg, colorectal liver metastasis, tumors that are difficult to surgically resect, or combined embolization plus surgical resection) [14]. Anesthetic techniques vary according to practice-specific and patient-specific needs; these have included local anesthetic infiltration, paravertebral block, thoracic epidural anesthesia, and newer fascial plane blocks (eg, serratus anterior plane, erector spinae plane, quadratus lumborum, and pectoral nerve blocks, as well as general anesthesia) [6].

Procedures for gynecological pathology — Several IR procedures involving percutaneous transcatheter embolization are used to manage gynecological pathology. Conscious sedation (ie, MAC) is employed for most of these procedures. Examples include:

●Uterine fibroid embolization – (See "Uterine fibroids (leiomyomas): Treatment with uterine artery embolization".)

●Uterine artery embolization for adenomyosis – (See "Uterine adenomyosis", section on 'Uterine artery embolization'.)

●Uterine artery embolization for arteriovenous malformation – (See "Differential diagnosis of genital tract bleeding in women", section on 'Arteriovenous malformation'.)

●Uterine artery embolization as emergency treatment for intractable postpartum acute uterine hemorrhage – (See "Postpartum hemorrhage: Medical and minimally invasive management", section on 'Consider uterine or hypogastric artery embolization'.)

●Ovarian vein embolization for pelvic congestion syndrome – (See "Vulvovaginal varicosities and pelvic congestion syndrome", section on 'Management of PCS'.)

Nephrostomy tube placement — Percutaneous nephrolithotomy is the primary treatment for large or multiple kidney stones, and percutaneous nephrostomy tube placement may be performed to treat obstruction between the kidney and the ureter due to pelvic tumors, retroperitoneal fibrosis, or prior injury. Patients may present with acute or chronic renal insufficiency or sepsis due to urinary tract infection. (See "Placement and management of indwelling ureteral stents" and "Kidney stones in adults: Surgical management of kidney and ureteral stones", section on 'Percutaneous nephrolithotomy'.)

Conscious sedation (ie, MAC) or neuraxial anesthesia (ie, spinal anesthesia, epidural anesthesia, or combined spinal-epidural anesthesia) may be used in many cases, depending on urgency of the procedure, hemodynamic stability, patient preferences, and positioning for the procedure. General anesthesia is typically preferred for procedures performed in a prone position [15,16].

Gastrostomy tube placement — Gastrostomy tubes are placed for feeding and/or suctioning of gastrointestinal contents in patients with defects in the mouth, esophagus, or stomach due to congenital lesions, trauma, prior cancer surgery, or neurologic conditions that make swallowing and eating difficult. To facilitate the procedure, the stomach may be inflated after insertion of a nasogastric tube [17]. (See "Gastrostomy tubes: Placement and routine care".)

Choice of anesthetic technique for endoscopic placement of gastrostomy tubes is based in part on the procedure-specific requirements, including expected duration and complexity. Patient-specific factors may also confer unique anesthetic considerations. Examples include:

●Neurologic disorders such as amyotrophic lateral sclerosis. (See "Perioperative care of the surgical patient with neurologic disease".)

●Neuromuscular disorders such as myasthenia gravis. (See "Anesthesia for the patient with myasthenia gravis".)

●Oropharyngeal or gastrointestinal space occupying lesions that have a high risk of regurgitation and aspiration. These patients may require general anesthesia with rapid sequence induction and endotracheal intubation. (See "Rapid sequence induction and intubation (RSII) for anesthesia".)

Moderate or deep sedation is often used for such patients if there are no risk factors for aspiration. Nevertheless, the anesthesiologist should be prepared to induce general anesthesia if it becomes necessary. (See "Anesthesia for gastrointestinal endoscopy in adults", section on 'Choice of anesthetic technique'.)

In some cases, palliative gastrostomy tube placement is necessary for a patient who may be at the end of their life. Examples include:

●End-stage neurologic disorders with inability to swallow due to central nervous system involvement. (See "Gastrostomy tubes: Uses, patient selection, and efficacy in adults", section on 'Patients with neurologic disorders'.)

●Advanced oropharyngeal cancer or distal mechanical gastrointestinal obstruction after radiation or surgical treatments. (See "Palliative care of bowel obstruction in cancer patients", section on 'Enteric tube decompression'.)

Such patients often request conscious sedation rather than general anesthesia to avoid endotracheal intubation. Consultation with the referring neurologist, oncologist, or palliative care specialist may be necessary. Guidance for clinical decision-making in these situations can be found in separate topics:

●(See "Informed procedural consent".)

●(See "Advance care planning and advance directives".)

●(See "Ethical issues in palliative care".)

●(See "Legal aspects in palliative and end-of-life care in the United States".)

●(See "Palliative care: Issues in the intensive care unit in adults".)

Vascular procedures — Certain elective vascular procedures such as endovascular aortic repair, or peripheral arterial balloon angioplasty, embolization, or thrombolysis may be performed in the IR suite. Anesthetic techniques for these procedures include conscious sedation (ie, MAC), neuraxial, or general anesthesia, as described in detail in other topics. (See "Anesthesia for endovascular aortic repair" and "Anesthesia for infrainguinal revascularization".)

For other types of elective or semi-elective vascular procedures, conscious sedation (ie, MAC) is typically sufficient:

●Vena cava filter placement (see "Placement of vena cava filters and their complications")

●Dialysis catheter placement (see "Central catheters for acute and chronic hemodialysis access and their management")

●Management of chronic venous disease (eg, varicose vein, superficial vein insufficiency) (see "Overview of lower extremity chronic venous disease", section on 'Management' and "Approach to treating symptomatic superficial venous insufficiency")

Endovascular management of traumatic injuries — Some traumatic injuries to vascular structures of the abdomen, retroperitoneum, and pelvis are managed as emergencies in the IR suite [18-20]. (See "Abdominal vascular injury" and "Overview of blunt and penetrating thoracic vascular injury in adults".)

Procedures to control bleeding — In selected patients (eg, those with noncompressible torso hemorrhage following traumatic injury), resuscitative endovascular balloon occlusion of the aorta (REBOA) is a temporizing measure to support vital organ perfusion, decrease the amount of bleeding distal to the occluded site, and provide a window of opportunity for resuscitation and definitive hemorrhage control [21-23]. (See "Endovascular methods for aortic control in trauma".)

Anesthetic management of REBOA is described in detail separately. (See "Anesthesia for adult trauma patients", section on 'Resuscitative endovascular balloon occlusion of the aorta'.)

Patients with severe pelvic injuries may require pelvic embolization to control bleeding from the pelvic venous plexus. (See "Severe pelvic fracture in the adult trauma patient".)

Conservative rather than surgical management is advocated for most patients with blunt solid organ injuries (eg, kidney, liver, spleen), sometimes requiring hepatic embolization procedures to control bleeding.

●Hepatic injury (see "Management of blunt and penetrating renal trauma")

●Splenic injury (see "Management of hepatic trauma in adults")

●Kidney injury (see "Management of splenic injury in the adult trauma patient")

POST-ANESTHESIA CARE — Ensuring optimal care in the post-anesthesia period is essential. (See "Overview of post-anesthetic care for adult patients".)

If the interventional radiology (IR) suite is located in an "off-site" procedural area, ideally recovery would be in an attached post-anesthesia care unit (PACU). This arrangement eliminates the need for patient transport over long distances or to a different hospital floor, which may be dangerous in those who are heavily sedated or critically ill.

If transport to a centrally located PACU is necessary, standard monitoring should be used during travel (eg, electrocardiography [ECG], pulse oximetry [SpO₂], noninvasive blood pressure [BP] cuff). For critically ill patients requiring transport to an intensive care unit (eg, those undergoing vascular procedures after severe traumatic injury), the intra-arterial pressure waveform and, if possible, respiratory rate and end-tidal carbon dioxide (ETCO₂) are continuously monitored as well. (See "Anesthesia for adult trauma patients", section on 'Postoperative considerations'.)

CLINICAL VIGNETTES — The following hypothetical clinical case examples illustrate the principles discussed in this topic:

●A 23 year-old otherwise healthy pregnant woman (33 weeks gestation age estimated by ultrasound) presents with obstructive nephropathy and urosepsis. She has left flank pain, nausea and vomiting, as well as hypotension and tachycardia. Magnetic resonance imaging (MRI) of her abdomen and pelvis reveals left pyelonephritis with obstructive calculus in the renal calyx. She is scheduled for emergency nephrostomy tube placement in the interventional radiology (IR) suite. Management decisions and actions taken by the anesthesiologist include:

•Selection of monitored anesthesia care (MAC) rather than general anesthesia, with plans to use propofol for sedation, fentanyl as an analgesic, and midazolam as an anxiolytic in very small incremental doses as needed. (See "Nonobstetric surgery in pregnant patients: Patient counseling, surgical considerations, and obstetric management", section on 'Fetal heart rate monitoring'.)

•Preparations for difficult airway management and aspiration risk in case immediate endotracheal intubation becomes necessary. (See "Anesthesia for nonobstetric surgery during pregnancy", section on 'Preparation for anesthesia'.)

•Adjusting the patient's position to accommodate the need for uterine displacement to ensure optimal hemodynamics, while allowing for adequate imaging and interventionalist access for placement of the nephrostomy tube. (See "Anesthesia for nonobstetric surgery during pregnancy", section on 'Positioning'.)

•Fetal heart rate monitoring during and after the procedure. Immediate availability of an obstetrician is ensured, in case emergency cesarean delivery becomes necessary.

This case illustrates challenging management decisions and rapid preparations for an emergency case in an off-site location and emphasizes the role of the anesthesiologist as a liaison between the interventionalist and other specialists (in this case, the obstetrician).

●A 67 year-old man with advanced amyotrophic lateral sclerosis causing significant bulbar weakness and inability to swallow presents to the IR suite for palliative gastrostomy tube placement. The patient requests that general anesthesia with endotracheal intubation be avoided. Challenges for the anesthesiologist include the need to fully discuss advanced directives with the patient, interventionalist, referring neurologist, and palliative medicine specialist; family members or the hospital chaplain may also be involved. In particular, a decision regarding whether endotracheal intubation is an option must be made after discussing the risks, benefits, and alternatives.

•If endotracheal intubation is an option, preparations for difficult airway management are made, as well as preparations for transport and further management in an intensive care unit in case weaning from controlled ventilation cannot be achieved.

•If endotracheal intubation is not an option, preparations are made to provide sedation with immediate availability of noninvasive ventilation support to achieve adequate oxygenation and ventilation in the IR suite (eg, continuous positive airway pressure, bilevel positive airway pressure, high flow nasal cannulae oxygen delivery) before beginning the procedure. (See "Modes of mechanical ventilation", section on 'Continuous positive airway pressure' and "Modes of mechanical ventilation", section on 'Bilevel positive airway pressure' and "Heated and humidified high-flow nasal oxygen in adults: Practical considerations and potential applications".)

This case illustrates difficult end-of-life management decisions and preparations that must be made before a procedure in an off-site location, with emphasis on the role of the anesthesiologist as a liaison between the patient and family members, the interventionalist, and other specialists (in this case, the neurologist, palliative care specialist, and chaplain).

●A 57 year-old male with advanced nonischemic cardiomyopathy and primary adrenal tumor presents to the IR suite for radiofrequency ablation of his primary lesion. The patient is not a good surgical candidate due to significant heart disease. The anesthesiologist's preprocedure evaluation and preparation includes:

•Assessment regarding whether pretreatment with antihypertensive agents (eg, alpha and beta blockers) is adequate before this semi-elective procedure. This typically requires direct communication with the referring endocrinologist and interventionalist.

•Ensuring that the patient's coagulation parameters are within normal limits.

•Preparations for invasive blood pressure (BP) monitoring, since radiofrequency ablation of adrenal tumors is associated with hypertensive crises (defined as diastolic BP >120 mmHg and/or systolic BP >180 mmHg) due to release of catecholamines from the adrenal gland. Preparations to establish adequate central venous access for infusion of vasoactive agents (eg, nicardipine) are also necessary.

•Preparations to manage emergencies such as hemorrhage due to inadvertent puncture of surrounding vascular structures or pneumothorax due to inadvertent puncture of the diaphragm or lung tissues [24]. A surgeon should be immediately available for emergency treatment of hemorrhage or a tension pneumothorax. (See "Thoracostomy tubes and catheters: Indications and tube selection in adults and children", section on 'Tension pneumothorax'.)

This case illustrates the need for extensive preparations for anesthetic management of a particularly challenging elective case with possible major complications in an off-site location, and emphasizes the role of the anesthesiologist as a liaison between the interventionalist and other specialists (in this case, the surgeon).

●A 26 year-old otherwise healthy female presents to the IR suite with pelvic fracture and associated pelvic hematoma. Computed tomography (CT) imaging reveals extravasation of contrast material into the pelvic floor, and emergency embolization is planned in the IR suite. The patient is hemodynamically unstable. Challenges for the anesthesiologist include:

•Lack of time for preparation due to emergency presentation. Calls for assistance from available anesthesiology staff are appropriate. Arrangements for access to blood products without delay is particularly critical, and often a major challenge for provision of adequate resuscitation in an off-site location. (See "Anesthesia for adult trauma patients", section on 'General principles'.)

•The need for insertion of an intra-arterial catheter and two large-bore peripheral intravenous catheters or a central venous catheter for administration of medications, fluids, and possibly blood transfusions. The intra-arterial catheter is placed in an upper extremity since perfusion to the lower extremity arteries will be temporarily interrupted during balloon occlusion of the aorta or iliac vessels. If necessary, the radiologist can assist with emergency placement of intravascular cannulae. (See "Anesthesia for adult trauma patients", section on 'Monitoring and intravenous access' and "Anesthesia for adult trauma patients", section on 'Resuscitative endovascular balloon occlusion of the aorta'.)

•The possibility of other injuries to visceral organs or major blood vessels in a patient with pelvic floor trauma. Hence, the anesthesiologist should be prepared for additional blood loss and unresolved hemodynamic instability following embolization of iliac vessels in the IR suite. (See "Anesthesia for adult trauma patients", section on 'Assessment for other causes of shock'.)

This case illustrates the challenges inherent in emergency preparations and management of trauma victims in an off-site location. Although trauma centers should have full monitoring capabilities and be stocked with routine and advanced airway capabilities, equipment for rapid transfusion, and a variety of catheters for intravascular and intra-arterial access, such equipment are not always immediately available in an off-site location. Furthermore, personnel that can provide assistance with delivery of such equipment and blood products, as well as assistance with ongoing resuscitation, are not always immediately available outside of the main operating room.

SUMMARY AND RECOMMENDATIONS

●There is an increasing need for anesthetic care in interventional radiology (IR) suites for patients who require complex or prolonged procedures or often have significant comorbidities. This setting poses challenges in anesthetic care due to its "off-site" location remote from the main operating room area, which necessitates special preparations including (see 'Overview of challenges' above and 'Preparation of anesthetic equipment' above):

•Many IR suites are located distant from the main operating room area, and are not designed for delivery of anesthetic care. In such settings, it is necessary to transport all anesthetic equipment and drugs to the IR suite.

•Placement of equipment within the suite may not be optimal for easy access by the anesthesia provider.

•Setting up specially designed lengths or extensions of intravenous tubing, breathing circuit tubing for the anesthesia machine, and the sampling catheter for monitoring respiratory gases (eg, end-tidal carbon dioxide [EtCO₂], expired inhaled anesthetic concentrations).

•Exposure of the anesthesia provider to ionizing radiation.

•Lack of IR staff experience with anesthesia-related emergencies

●Patients undergoing IR procedures are typically receiving care from a different in-hospital service or are referred for the procedure from an outside practitioner. Thus, the anesthesiologist often serves as a liaison between the interventionalist and the primary care physician or specialty team during preoperative assessment, ensuring that preoperative patient status is optimal, preparations have been made for any patient-specific issues, and patient education regarding periprocedural expectations has been accomplished. (See 'Preanesthesia patient evaluation' above.)

●Selection of an anesthetic technique (ie, monitored anesthesia care [MAC] with minimal or deep sedation, regional or neuraxial anesthesia, general anesthesia) depends on the procedure-specific and patient-specific considerations (table 1) (see 'Anesthetic techniques' above):

•Procedure-specific factors

-Type of procedure

-Anticipated duration and complexity of the procedure

-Need for uncomfortable or unconventional patient positioning

-Requirement for absence of movement or intermittent apnea

-Exposure to radiation

•Patient-specific factors

-Hemodynamic instability

-Altered level of consciousness with risk for aspiration, unwanted patient movement

-Inability to cooperate for other reasons (eg, chronic or acute pain, severe anxiety)

-Inability to lie supine

-History of difficult airway

-Obstructive sleep apnea or class II obesity

-Patient preference

●Anesthetic considerations for specific procedures are noted above (eg, neurologic procedures [intracranial or spinal interventions], procedures to treat gynecologic or hepatic pathology, placement of a nephrostomy or gastrostomy tube, elective and emergency vascular procedures). (See 'Considerations for specific procedures' above.)

●Optimal care in the post-anesthesia period is ensured, ideally in a post-anesthesia care unit (PACU) attached to the IR suite to eliminate patient transport for long distances. If transport to a centrally located PACU is necessary, standard monitoring should be used during travel (eg, electrocardiography [ECG], pulse oximetry [SpO₂], noninvasive blood pressure [BP] cuff). (See 'Post-anesthesia care' above.)