Anesthesia in the Radiology Suite

It is obvious from the preceding discussion that delivery of anesthesia care in the radiology suite is not to be undertaken lightly. Ideally, the anesthesiologist should be involved at the earliest possible stage in planning the delivery of such care. Open communication with radiologists and early consultation of the anesthesiologist will maximize efficient operation of both departments by providing timely, quality anesthetic care and minimizing delays or cancellation of necessary procedures. Involvement of the anesthesiology department in the development of sedation/analgesia guidelines, as well as training of involved personnel as mandated by the Joint Commission on Accreditation of Healthcare Organizations and encouraged by the ASA, is an important step in providing quality anesthetic care in this challenging environment.^{[6] [26]} Nonanesthesiologist providers of sedation/analgesia who know and understand the guidelines regarding sedation/analgesia become adept at recognizing patients who are at higher risk for either sedation failure or complications and are thus able to provide more timely notification of appropriate anesthesia personnel that assistance is required. Open communication between the departments of radiology and anesthesiology likewise facilitates earlier notification of high-risk patients and more timely delivery of quality anesthetic care.

In the past, much variability was noted in adherence to the modern guidelines regarding provision of anesthesia care, including lack of preoperative evaluation, lack of informed consent, and lack of sufficient dedicated personnel to monitor both pediatric and adult patients during sedation/analgesia.^{[27] [28]} It would be hoped that increased involvement by anesthesiologists in this arena will improve the delivery of care.

Given adherence to the applicable standards of care, a number of anesthesia techniques are used in the radiology suite. Minimal to moderate sedation/analgesia is the technique used for most patients undergoing these procedures.^{[12] [28]} For most adults, combinations of intravenous benzodiazepines and opioids (i.e., titration of midazolam and fentanyl) are sufficient to ensure comfort during the procedure. As noted earlier, the use of more potent anesthetic agents such as propofol, methohexital, and ketamine is best reserved for specialists in anesthesia.^[6] However, understanding the procedure in question is important in selection of the appropriate anesthetic technique. The patient's condition, the anticipated level of stimulation, and patient position during the procedure are all important considerations. A patient undergoing ultrasound-guided hepatic biopsy might have ascites, which would render that patient prone to aspiration if sedated, and penetration of the hepatic capsule by the biopsy needle would be anticipated to be quite painful. Such a patient might benefit from general anesthesia rather than sedation/analgesia. Procedures that might be anticipated to last several hours may best be performed with general anesthesia at the outset rather than late conversion after failure of sedation/analgesia, when patient access might be limited by catheter placement and radiologic equipment. The importance of open communication between radiologists and the anesthesiologist cannot be overemphasized.

Certain procedures performed in the radiology suite may necessitate specific anesthetic techniques for maximum patient benefit. At the Mayo Clinic, we have found that patients undergoing RF ablation of painful osteolytic lesions seem to benefit from continuous regional anesthesia after the procedure, which is usually performed under general anesthesia.^[10] The role of regional anesthetic techniques may be expected to grow in nonoperative anesthetizing locations as further advances in treatment modalities occur (also see Chapter 43 and Chapter 44 ).

Pediatric patients merit special consideration. Some radiologic procedures require patients to remain still for prolonged periods, which may not be possible for infants and children, even with sedation/analgesia. When it is thought that the procedure can be performed with sedation/analgesia, healthier infants and children frequently receive chloral hydrate orally for radiologic procedures

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Patients with difficult airways, whether anticipated or not, can be problematic in settings outside the operating suite (also see Chapter 42 ). I prefer to perform anticipated difficult endotracheal intubations in the operating suite with its improved availability of skilled assistants and specialized equipment. Once the airway is controlled, the patient can be transported to the site of the planned procedure should it be necessary to perform the procedure outside the operating suite. Unanticipated difficult airways can place an anesthesiologist outside the operating suite in a difficult position. My personal preference in a patient with an anticipated difficult intubation is to switch to the operative suite at a later date, if at all possible. If not possible, understanding of the ASA algorithm for management of a difficult airway and the availability of emergency airway equipment, as well as skilled assistants in the remote location, are obviously key to the patient's well-being.^{[29] [30]}