Interventional radiology (IR) procedures vary a great deal (Table 31.2), but very frequently they are emergent and are needed in unstable patients. Almost 70 % of the procedures are urgent and booked less than 48 h ahead of time. Most scheduled IR procedures are performed with physician- or nurse-administered sedation; however, these emergent cases frequently require the involvement of an anesthesiologist or anesthesia team. In addition, patients with significant comorbidities may need anesthesia involvement to optimize their medical condition in a way that allows for their procedure to be completed. Preprocedural assessment and discussion with the interventionalist is imperative to developing a safe and realistic anesthetic plan.

Interventional procedures require patients to be in the supine, prone, or even lateral positions, sometimes for extended time periods. Most interventional procedures require the placement of needles into blood vessels, organs, or spaces, and to decrease adverse outcomes, the patients need to be still, whether it is a result of cooperation or sedation. The ability to cooperate is instrumental in these procedures, and many patients with dementia and psychiatric disorders, inpatients with delirium, or pediatric patients may be unable to cooperate. Because of these situations, many patients may require deep sedation or even general anesthesia (GA) with a laryngeal mask airway (LMA) or endotracheal tube depending on the patient comorbidities and length of procedure. Many of the emergent cases may involve hemodynamically unstable patients. This is often a result of sepsis, hepatic failure, or gastrointestinal or postsurgical bleeding. Procedures such as arterial embolization, abscess drainage, TIPS, or portal sclerotherapy necessitate the need for anesthesiology involvement due to the potential for continuous patient monitoring and resuscitation, in addition to the anesthetic.

Other potential issues during interventional procedures are hypothermia, which mostly affects elderly and pediatric patients, and radiation exposure. It is important to monitor the patient’s temperature throughout the procedure, in addition to having the ability to change room temperature or apply forced warm-air heating devices. Patients are at higher risk for hypothermia during longer procedures. According to most manufacturers, the temperature tolerance of the computers and machinery is 68° F, and therefore, the thermostat should be set to this level.

Magnetic resonance imaging (MRI) procedures are unique among the NORA locations, in that they are used solely for diagnostic testing (Fig. 31.1). This will likely change in the future as many interventionalists plan to use the new 3-Tesla (3 T) units to perform procedures similar to those done with a CT scan. MRI studies can be several hours in duration depending on what part of the body is being imaged, and it is essential that the patient remain immobile for optimal imaging. Anesthesia involvement is common in pediatric patients with the inability to cooperate or lay still and adult patients with claustrophobia or anxiety.

The preprocedural assessment of the patient and discussion with the radiology team should uncover the need for anesthetic involvement and allow for appropriate planning. These patients can require anything from moderate sedation to a GA, and this will be determined for each patient individually. Regardless, most patients receive propofol for sedation, with a total intravenous anesthesia technique used for general anesthesia. At times, the risks/benefits of GA should be discussed with the radiologist, patient, and their family if the information gained by the study will not change the patient’s outcome.

The MRI suite is quite unique in the challenges it presents to anesthetic personnel. Airway equipment (including laryngoscopes), medication pumps, poles, monitors, the anesthesia machine, and cart must all be MRI compatible. Many radiologic suites have an induction room separate from the procedure rooms where the patient can be attached to monitors, an IV started and then safely placed under sedation or under general anesthesia with airway securement. Patients would then be transported to the MRI suite and transferred to the MRI table. If an MRI-compatible machine or medication pump is not available, then they must be located outside the room with adequate extensions for intravenous tubing and breathing circuits. Organization of intravenous or arterial lines, monitoring cables, and either supplemental oxygen tubing or the ventilator circuit is important so they are not dislodged while moving the patient. During the MRI exam, patients are always located in a separate room, but patient and patient monitors must be viewed at all times via a window or video screen.

Complications to be concerned about include oversedation or apnea leading to the need to emergently obtaining and maintaining the airway. One cannot emergently enter the MRI suite as the magnet has to be turned off before anyone can enter, which takes time. Patients with cardiovascular disease, particularly arrhythmias or coronary artery disease, may be difficult to monitor given the ECG interference from the MRI machine. Pediatric patients at higher risk for adverse events during propofol administration were those undergoing longer procedures, those with American Society of Anesthesiologist’s physical status, or those with airway abnormalities.

All staff working in MRI should undergo MRI safety training as to not bring harm to themselves or the patients. Any patient with ferrous implants may not safely undergo an MRI for risk of dislodging the device. Common devices prohibiting patients from undergoing an MRI are listed in Table 31.3. Titanium implants or clips are considered safe for MRI. Patients with tattoos should be warned that they are at risk for burn injury as some tattoo ink contains high amounts of ferrous oxide.

Computerized tomography (CT) scans can be used for diagnostic and/or interventional procedures. Diagnostic procedures are quite quick and patients typically do not require the administration of sedation or analgesia. Those nontypical patients are identical to patients requiring anesthetic involvement for MRI: psychiatric illnesses, anxiety, movement disorders, intellectual disabilities, or chronic pain. For these patients, sedation, analgesia, and possibly even GA may be needed in order to complete the study. Other patients requiring anesthetic involvement are those who are hemodynamically unstable or those already intubated from the OR, emergency room (ER), or ICU.