Anesthesia in Satellite LocationsBrenda A. Gentz, MD

Department of AnesthesiologyUniversity of Arizona College of Medicine

Tucson, Arizona

Learning Objectives:As a result of completing this activity, the participantwill be able to� Identify potential complications and hazards spe-

cific to remote satellite locations� Identify and implement current anesthesia guidelines

with regard to the monitoring of oxygen saturationand ventilation of patients in satellite locations

� Describe safe airway and anesthetic managementtechniques for procedures in remote locations

� Predict and identify the challenges of monitoringpatients and maintaining normothermia in remotelocations

Author Disclosure Information:Dr. Gentz has disclosed that she has no financialinterests in or significant relationship with anycommercial companies pertaining to this educationalactivity.

Providing anesthesia outside of the operating roompresents a unique set of challenges. The standardsand principles that underlie care of the patient in the

operating room should be maintained in satellite locations(Table 1). However, creating a safe anesthetic environmentmay have significant barriers with both expected andunexpected challenges. Patients may not be referred to ananesthesia preoperative clinic, resulting in adults andchildren with multiple comorbidities presenting for anes-

thesia without a prior history and physical examinationbeing completed. The availability of anesthesia equipmentand support personnel may be limited. The layout, smallroom size, and special requirements of the satellite locationmay limit access to the patient. Monitoring ventilation inthese patients has been identified as one of the two keyelements, along with pulse oximetry, in preventing seriouscomplications including hypoxia, brain injury, and evendeath (Supplemental Digital Content 1, http://links.lww.com/ASA/A256). The anesthesiologist providing anesthe-sia in remote locations must have a good understanding ofthe considerations unique to the site, know the risks andbenefits of different anesthetic techniques, and have apreplanned strategy for dealing with unexpected events.

Monitoring the ventilation of these patients in

addition to the use of pulse oximetry has been

identified as one of the two key elements in

preventing serious complications including

hypoxia, brain injury, and even death.

32

Table 1. Hospital Satellite LocationsEndoscopy suites (pulmonary and gastrointestinal)

Radiation oncology

Computed tomography (CT)

Magnetic resonance imaging (MRI)

Interventional radiology

Cardiac catheterization lab

Nuclear imaging

Supplemental digital content is available for this article. Direct URLcitations appear in the printed text and are available in both the HTML

and PDF versions of this article. Links to the digital files are provided in

the HTML and PDF text of this article on the Journal’s Web site

(www.asa-refresher.com).

USE OF ANESTHESIA IN SATELLITE LOCATIONS

General TrendsWhile in most institutions, pediatric patients remain thelargest group of patients requiring anesthesia in remote loca-tions, there seems to be an increasing demand foranesthesia services for adult patients as well. Within the adultpopulations, there is a need for assistance with vulnerable andcritically ill elderly patients, adults with developmental delays,and patients with claustrophobia, chronic pain disorders, oropioid tolerance. Patients with significant cardiopulmonarydisease, including transplant recipients or candidates as wellas patients with implantable cardiac defibrillators, ventricularassist devices, cardiomyopathies, or end-stage pulmonarydisease, are requiring interventional procedures. In some in-stitutions, nearly 70% of operations are booked less than48 hours in advance because of the relatively urgent or emer-gent nature of the procedure.1 Hospitals in particular are nowrequesting and sometimes paying for anesthesia services forthese patients, as it is thought that the presence of anesthesi-ologists may increase patient comfort, improve the overallsafety of care, decrease the difficulty of the procedure, shortenthe duration of recovery, and increase the number of patientswho may receive care. Operating room time is at a premiuminside many hospitals, so completing endoscopic, radiological,and therapeutic procedures in remote locations may preventdelays in diagnostic and therapeutic interventions.

Complications Related to Remote LocationsMonitored anesthesia care may be the technique of choice formany procedures in remote locations. If the patient is able tocooperate and intense stimulation is not expected, light seda-tion may be all that is required. However, if the patient is notmonitored closely and additional sedation is required for atechnically difficult portion of a procedure, respiratory de-pression can result. Monitoring should be able to detect in-adequate oxygenation as well as ventilation. Distraction byambient noise may keep the anesthesiologist from noticingthat alarms are being activated and may slow the response.Delays can also occur when the monitor is turned off, is poorlyfunctioning (such as the pulse oximeter in a low-perfusionstate), or if there is a physical barrier such as the patient in aprone position or physically distant from the physician, as in amagnetic resonance imaging (MRI) scanner. Most patientswho experience injuries related to oversedation during moni-tored anesthesia care receive a combination of two drugs, abenzodiazepine and an opioid or propofol, plus others.2

In 2009, the American Society of Anesthesiologists(ASA) Closed Claims database was more broadly analyzedto evaluate the risk and safety of anesthesia in remotelocations.3 The cases were limited to 1990 or later andexcluded all obstetric, acute pain, and chronic pain pro-cedures. Eighty-seven remote location claims and 3,287operating room claims were reviewed. Patients receivinganesthesia in remote locations were found to be older andto have an increased severity of illness, and their proce-dures were more likely to be described as emergent when

compared with those performed in the operating room.The predominant anesthetic technique in remote locationswas monitored anesthesia care, which was eight timesmore frequent than in operating room claims. Inadequateoxygenation and ventilation was the most common respi-ratory claims event (21%) in remote locations (Supple-mental Digital Content 2, http://links.lww.com/ASA/A257). In contrast, only 3% of claims resulted from in-adequate oxygenation and ventilation when care wasprovided in the operating room (Supplemental DigitalContent 3, http://links.lww.com/ASA/A258). The otherrespiratory events included esophageal intubation, diffi-cult intubation, and aspiration of gastric contents. An ab-solute or relative overdose of sedative, hypnotic, oranalgesic drugs, alone or in combination, led to respiratorydepression in 30% of the remote location claims. Morethan half of the cases occurred in the gastrointestinal (GI)suite, and 70% of the cases that happened in radiologyoccurred in the MRI scanner.3,4

Most patients who experience injuries related

to oversedation during monitored anesthesia

care receive a combination of two drugs,

a benzodiazepine and an opioid or propofol,

plus others.

The ASA’s Standards for Basic Anesthetic Monitoringstate that ‘‘during all anesthetics, the patient’s oxygen,ventilation, circulation and temperature shall be con-tinually evaluated.’’5 Despite these known standards, inthe ASA closed claims experience with remote locations, acapnograph was used in only a minority of cases associatedwith oversedation (15%) and no respiratory monitoringwas found in an additional 15%.3 In a report of 154 deathsoccurring after upper GI endoscopy, 88% of the patientsreceived intravenous sedation but only 56% had any formof respiratory monitoring, and in such cases only pulseoximetry was used.6 During sedation, airway obstructionor hypoventilation may occur that is not detected untilhypoxia is indicated by pulse oximetry. Capnography willassist in the early identification of abnormal breathingpatterns (lack of detected carbon dioxide) that may resultin hypoxia.7 Pulse oximetry and capnography used inconjunction with one another seems to be much safer thanpulse oximetry alone.8 The benefits of capnography havebeen touted as providing early recognition of ventilatorydepression, preventing inappropriate administration ofadditional sedation, and alerting the anesthesiologist thatan airway intervention may be required. As of July 1,2011, the ASA has recommended that ‘‘during moderate ordeep sedation the adequacy of ventilation shall be eval-uated by continual observation of qualitative clinical signsand monitoring for the presence of exhaled carbon dioxide

33Anesthesia in Satellite Locations

unless precluded or invalidated by the nature of thepatient, procedure, or equipment’’9 (Supplemental DigitalContent 4, http://links.lww.com/ASA/A259).

Pulse oximetry and capnography used in

conjunction with one another appears to be

much safer than pulse oximetry alone.

Monitoring of patients in remote locations is paramountto the delivery of safe anesthesia. The number of deathsfrom complications occurring in remote locations was al-most double when compared with operating room claims.3

Care was found to be substandard in 54% of claims inremote locations versus 32% of operating room closedclaims. Patient injury was judged to have been preventablein four times as many remote location cases when com-pared with procedures in the operating room. Cardio-vascular events, equipment failure or malfunction, ormedication-related events did not differ between remotelocation and operating room claims.3,4

Safety and Setup in Remote LocationsStandardized monitoring and anesthesia equipment shouldbe available in remote locations. This includes clearly la-beled and easily accessible emergency equipment such ascode carts and defibrillators. The personnel in the proce-dure room will usually include a technician, a member ofthe nursing staff, and the anesthesiologist. These in-dividuals should know how to call for and access medicalassistance in case of an emergency. They should know notonly how to find the code drugs, emergency equipment,and defibrillators, but how to operate them. If a largenumber of the patients receiving care are children, it maybe appropriate to have ancillary staff with pediatric nurs-ing skills available as well. Access to difficult airwayequipment has been recommended. A portable difficultairway cart or tackle box that can be transferred to theremote location might be desirable. To properly monitorpatients, telemetry, clear observation windows, or a re-mote camera system may be used in those areas wherediagnostic or therapeutic equipment may pose a health riskto anesthesia personnel.

SEDATION AND GENERAL ANESTHESIA

Anesthesia in remote locations is unique in that the pro-cedures may be noninvasive and can either have brief pe-riods of intense stimulation or prolonged periods withminimal stimulation. Some studies cannot be performedadequately or safely if movement is detected and, thus,must be completed under general anesthesia. This is espe-cially true if control of breathing is required. Dia-phragmatic motion can make procedures in which a smallarea must be targeted near the diaphragm, such as the liver,adrenal glands, kidneys, or lower lung bases, difficult.7

The age, body habitus, patient comorbidities, presenceof intravenous access, and available equipment all playimportant roles in the choice of anesthesia. Anestheticdrugs that may be chosen include dexmedetomidine,chloral hydrate, midazolam, propofol, ketamine, or vola-tile anesthetics. When it is anticipated that the patient willbe transported between several locations for diagnosticand therapeutic procedures, propofol may be used as partof a total intravenous anesthetic. Some of these medi-cations may be used in combination (i.e., propofol andketamine), but monitoring for respiratory depression iscritical. As noted in the ASA’s Statement on Safe Use ofPropofol, sedation is a continuum, and the individual pa-tient’s response is not always predictable: ‘‘Even if moder-ate sedation is intended, patients receiving propofol shouldreceive care consistent with that required for deep seda-tion.’’10 Opioids may be required in patients who are un-able to lie supine or be positioned for a procedure becauseof pain. The addition of opioids may increase the risk ofrespiratory depression.

Airway IssuesA complete history and physical examination, includingthe airway, must be completed in all patients before thedelivery of anesthesia. Despite the remote location, theASA’s Practice Guidelines for Management of the DifficultAirway should be followed if a difficult airway is suspectedor anticipated.11 Determining the most appropriate loca-tion to secure the patient’s airway can sometimes be chal-lenging. Procedure rooms or operating rooms closer toadditional trained personnel and equipment may facilitatethe intubation, but require transfer of the patient on agurney with sedation to the remote location. At least oneadditional individual must be immediately available toserve as an assistant in difficult airway management. Ifintubation is to be carried out in the remote location, oneportable storage unit that contains specialized equipmentfor difficult airway management should be readily at hand.Fiberoptic intubation equipment compatible with endo-scopic systems may be available in some locations such asthe GI suite.

Temperature RegulationPostoperative hypothermia has been shown to increaseperioperative complications including wound infections,myocardial infarctions, and increased blood transfusion re-quirements in surgical patients.12–14 Mild hypothermia in-creases the respiratory rate, which can progress torespiratory depression when hypothermia worsens. ‘‘Colddiuresis’’ can result in an increase in urinary flow from acold-induced reduction in cellular enzyme activity with de-creased distal tubular reabsorption of sodium and water.Hypothermia also inhibits the enzymatic reactions of thecoagulation cascade, impairing coagulation.15 Acidosis,mild ileus, depressed hepatic function, hyperglycemia, im-paired healing, and altered pharmacokinetic and pharma-codynamic properties of anesthetic drugs may also occur.16

34 Gentz

Unlike operating rooms, temperature adjustment formany off-site locations may not be controlled from insidethe procedure room.17 Equipment such as computedtomography (CT) or MRI scanners can generateconsiderable heat and require active cooling to operateproperly. Low ambient temperatures can result in rapiddecrease in the patient’s core temperature. This can bepronounced in prolonged or difficult procedures or whena significant percentage of the patient’s body must beexposed to complete the procedure. It may be that thethermostat can be adjusted. At Brigham and Women’sHospital, the thermostat in the interventional radiologyrooms was reset after checking with the manufacturer anddetermining that the temperature tolerance of their par-ticular equipment was 681F.7 Effective methods forwarming patients include forced warm air blankets, fluidwarmers, and radiant heaters. Compatibility with the re-mote location equipment must be confirmed before usingany such device to avoid injury to personnel or a patient. Ifpatients cannot be warmed in the remote location, pre-warming may be helpful.18 Skin, rectal, and esophagealprobes as well as infrared ear thermometers may be usedfor monitoring temperatures in remote locations.19 Cau-tion should be exercised when using the MRI scanner, assome types of temperature-monitoring devices may pro-vide erroneous readings or result in patient injury (i.e.,burns).20 MRI-compatible temperature probes are avail-able and should be used at all times.

ANESTHETIC CONSIDERATIONS FOR SATELLITELOCATIONS

GastroenterologyThe role of the anesthesiologists in the GI endoscopy suite hasbecome more prominent as the need for efficient, but safeanesthesia and analgesia has increased. There are select pa-tient groups who are more likely than others to require theexpertise of an anesthesiologist. The American Society ofGastrointestinal Endoscopy, in conjunction with the ASA, hasidentified patients at increased risk due to airway disease whorequire consultation (Tables 2 and 3).21–22 (SupplementalDigital Content 5, http://links.lww.com/ASA/A260; Supple-mental Digital Content 6, http://links.lww.com/ASA/A261).

Some endoscopic procedures will require deeper levelsof sedation to achieve patient comfort and allow the gas-troenterologist to perform the procedure safely. These in-clude endoscopic retrograde cholangiopancreatography(ERCP), endoscopic ultrasound (US), and emergencytherapeutic procedures. Small changes in position mayhave adverse effects during sphincterotomy, insertion ofneedles for fine needle aspiration, or when electrocauteryis being used.22 The deeper levels of sedation that arerequired are not without risk. Half of the oversedationclaims in the ASA closed claims study occurred in the GIsuite.3 Seven of these claims involved ERCP, seven duringupper GI endoscopy with the remaining claim involving a

patient who underwent a colonoscopy. The incidence ofcardiopulmonary complications associated with endo-scopic procedures ranges from 0.01 to 5.4 per thousandwith ERCP having the highest rate of hypoxemia.23 Theincreased risk with ERCP is related to the need for deepsedation, long duration of the examination, prone posi-tioning of the patient, advanced mean age, and frequentcomorbid diseases.24 ERCP has been singled out as a pro-cedure in which monitoring of exhaled carbon dioxideshould be considered.25 Due to prone positioning andinability to quickly secure a compromised airway, these

Table 2. Guideline for Anesthesiology AssistanceDuring Gastrointestinal EndoscopyAnesthesiologist assistance may be considered in the followingsituations:

Prolonged or therapeutic endoscopic procedure requiring deepsedation

Anticipated intolerance to standard sedatives

Increased risk for complication because of severe comorbidity(ASA class III or greater)

Increased risk for airway obstruction because of anatomical variant

Reprinted from Vargo et al.,21 with permission from the American Society forGastrointestinal Endoscopy.

Table 3. Example of Airway Assessment Procedurefor Sedation and AnalgesiaPositive-pressure ventilation, with or without endotracheal intubation,may be necessary if respiratory compromise develops during sedation/analgesia. This may be more difficult in patients with atypical airwayanatomy. Also, some airway abnormalities may increase the likelihood ofairway obstruction during spontaneous ventilation. Factors that may beassociated with difficulty in airway management are:

History

Previous problems with anesthesia or sedation

Stridor, snoring, or sleep apnea

Dysmorphic facial features (e.g., Pierre-Robin syndrome, trisomy 21)

Advanced rheumatoid arthritis

Physical examination

Habitus

Significant obesity (especially involving the neck and facialstructures)

Head and neck

Short neck, limited neck extension, decreased hyoid-mentaldistance (o3 cm in an adult), cervical spine disease or trauma,tracheal deviation

Mouth

Small opening (o3 cm in an adult); edentulous; protrudingincisors; loose or capped teeth; high arched palate;macroglossia; tonsillar hypertrophy; nonvisible uvula

Jaw

Micrognathia, retrognathia, trismus, significant malocclusion

Reprinted with permission from ‘‘Practice guidelines for sedation and analgesiaby non-anesthesiologists.’’22

35Anesthesia in Satellite Locations

procedures may best be performed under general endo-tracheal anesthesia.

Most patients who undergo endoscopic US or upperendoscopy receive some combination of opioid (usuallyfentanyl), benzodiazepine (midazolam), or propofol. Top-ical lidocaine may be added to decrease the reactivity of theairway. A propofol bolus may be required for introductionof the endoscope. Propofol has the benefit of rapid onsetand offset of effect, but does not provide analgesia. Pa-tients can easily transition to a deeper level of anesthesiathan was intended. One investigation looked at the use ofpropofol in 202 patients undergoing colonoscopy andfound that the dosages of propofol administered were as-sociated with electroencephalographic suppression andlack of recall consistent with general anesthesia.26 Thevasodilating effects of propofol should be considered in theelderly, in patients with significant cardiovascular disease,and in patients who have undergone a bowel preparation.

Interventional RadiologyInterventional radiology now encompasses a broad spec-trum of minimally invasive procedures. Anesthesiologistsmay be asked to provide deep sedation or general anes-thesia for a wide range of procedures including percuta-neous drainage for urological and hepatobiliary infections;embolization for GI, postpartum, or traumatic bleeding;ablation of venous and arteriovenous malformations;aortic injury repair; vascular stenting procedures; percu-taneous feeding tubes; and intravenous access devices.Cross-sectional imaging modalities may use CT, MRI, andUS to guide percutaneous biopsies, facilitate aspirations,and place precisely targeted drains. Transjugular intra-hepatic portosystemic shunt procedures may be performedunder fluoroscopic guidance for recurrent variceal bleed-ing, refractory ascites, or hepatorenal syndrome. Anes-thesiologists should develop an understanding of theprocedures and the pathophysiology and comorbiditiesexpected for the patient population.

MRIThere is agreement that the safety, preparation, and care ofpatients who undergo MRIs represent a shared responsi-bility between the anesthesiologists, radiologists, MRItechnologists, and nursing staff involved in their care. In2009, the ASA published its ‘‘Practice Advisory on Anes-thetic Care for Magnetic Resonance Imaging.’’27 The MRIsuite is considered to be a hazardous location because ofthe presence of a strong static magnetic field, high-frequency electromagnetic (radiofrequency) waves, and atime-varied magnetic field. Additional dangers includeacoustic noise, systemic and localized heating, and acci-dental projectiles. The static and dynamic magnetic fieldsin conjunction with the radiofrequency energy emissionsmay interfere with monitoring capabilities. Seventy per-cent of the ASA claims in radiology occurred when usingthe MRI scanner.3 Contributing factors include an ob-structed view of the patient, risk for oversedation, and

non-MRI-compatible equipment. Fires and burns haveoccurred with incompatible cardiac electrodes and withlooping of temperature probes or oxygen cables in-appropriately insulated for MRI use.

The anesthetic care providers, ancillary support per-sonnel, and patients need to be properly screened for fer-romagnetic materials (Table 4). Some implants and deviceshave well-established risks. Others, like eyeliner tattoosthat may cause burns, swelling, and puffiness are less wellknown. Equipment and drugs for anesthetic care in theMRI suite should be similar to what is provided in theoperating room. Ideally, an MRI-safe anesthesia machineshould be available. Metals such as stainless steel, nickel, andtitanium as well as plastic are all suitable for the MRI envi-ronment. If total intravenous anesthesia is used, it should beadministered through either an MRI-compatible pump inthe MRI scanner magnet room (Zone IV) or in Zone III withintravenous tubing passed through a wave guide. Periodicboluses may be given in either Zone III or IV (Table 5).27

The type of anesthesia needed will depend on the studyrequirements. Motion artifact and the necessity for breath-holding may increase the need for general anesthesia,muscle relaxation, or a combination of the two. The du-ration of the procedure as well as patient positioning willundoubtedly play a role in the practitioner’s decision to usea device to secure the airway. Although there is a highsuccess rate in imaging patients who have received seda-tion or light anesthesia, the ASA Practice Advisory onAnesthetic Care for Magnetic Resonance Imaging high-lighted these techniques as being associated with ‘‘respi-ratory depression, oxygen desaturation, bronchospasm,drowsiness, agitation, and vomiting.’’27 When thesecomplications occur, the study must be interrupted andemergency intervention undertaken. Apnea monitoring(detection of exhaled carbon dioxide) may decrease risksduring both moderate and deep sedation.

Table 4. MRI-incompatible Implants, Devices, andPersonal ItemsSpinal cord stimulators Stethoscopes

Aneurysm clips Non-MRI compatible intravenouspumps

Surgical clips Non-MRI compatible oxygen tanks

Prosthetic heart valves Pens

Coronary artery stents Watches

Implanted dental magnetkeepers

Wallets

Eyeliner tattoo Hair clips

Deep brain stimulator Name tags

Middle ear prostheses Pagers

Pacemakers Cell phones

Cardioverter–defibrillators Credit cards

Batteries

MRI¼magnetic resonance imaging.

36 Gentz

If an emergency does occur, a preplanned strategy isadvised. The patient should be moved from Zone IV of theMRI suite to a previously designated ‘‘safe’’ location. A callfor help and cardiopulmonary resuscitation should beginimmediately, if needed. The safe location should have adefibrillator, a vital signs monitor, and a code cart thatcontains resuscitation drugs, airway equipment, oxygen,and suction.27 Anesthesiologists should be familiar withprojectile emergencies, fire response, and ‘‘quenching’’ thatcan occur as a result of intentional shutdown of the MRIscanner.

CTPediatric and adult patients undergoing various proce-dures performed under CT guidance may require the careof an anesthesiologist. There can be limited access to thepatient, as with providing anesthesia to patients under-going MRI. The obvious advantage is that without thestrong MRI field, there are few compatibility problemswith equipment. The CT scans tend to be much quickerthan MRI scans. Pediatric patients may need to receivesedation for short, noninvasive scans, but for longer ortargeted interventional procedures general anesthesia maybe required. Because of the high levels of ionizing radia-tion, anesthesia personnel should monitor the patient

through a radiation-shielded window and stop thescan when entering the room if emergency care must beprovided.28

Radiation OncologyRadiation therapy is a significant component of the treat-ment plan associated with many malignancies. Externalbeam radiation is delivered to a very specific target over aperiod of weeks to affect tumors. Absolute immobility isrequired at the target site when the patients, frequentlychildren, are being treated. Because of the high levels ofradiation, the patients are isolated and shielded. Remotemonitors for electrocardiography, blood pressure, andpulse oximetry may be required. The anesthesia equipmentand computer monitors will need to be rechecked eachtime the gantry is repositioned.

Within the radiation oncology suite, patients may needto be transferred between procedure rooms. For example,CT-guided interstitial brachytherapy is currently being in-stituted to treat locally advanced uterine cervical cancer.29

These patients may have the tandem and ovoids placed in aprocedure room and then are transferred to the MRI orCT scanner while sedated or under general anesthesia.The operating radiation oncologists can then determinewhether the position of insertion and depth of the needlesis optimal.

Like MRI and CT scanners, the radiation oncologyroom can be cool. If the patient’s core temperature is low,the radiation oncologist should be asked if a forced airwarming blanket can be used. Although the treatments arepainless, patients who receive daily therapy sometimes re-quire antiemetics and intravenous fluid after the procedureis completed.

PATIENT TRANSPORT AND POSTPROCEDURERECOVERY

The decision to extubate the trachea at the remote locationwill depend on the patient’s airway complexity and avail-able personnel. Similar to the operating room, if ex-tubation is performed in the remote location, emergencydrugs, airway equipment, a patient monitor, and oxygensupply should be available. This same emergency equip-ment should be carried with the patient to the recoveryarea and should include a portable suction machine in casethe airway becomes compromised en route.

A recovery area specifically dedicated to the post-procedural recovery of endoscopy or remote location pa-tients is preferred due to the high turnover rate. Mostpatients who undergo endoscopy procedures are ready fordischarge in less than 1 hour. Taking care of patients whohave undergone short procedures can be overwhelming forstaff trying to simultaneously treat patients who have un-dergone more complex surgical procedures, and may cre-ate a bottleneck in the discharge process.

Despite recovering relatively quickly from their proce-dure, these patients may still lack physical coordination

Table 5. Zone DefinitionsZone I This region includes all areas that are freely

accessible to the general public. This area istypically outside the MR environment itself and isthe area through which patients, healthcarepersonnel, and other employees of the MR siteaccess the MR environment.

Zone II This area is the interface between the publiclyaccessible uncontrolled Zone I and the strictlycontrolled Zone III (see below). Typically, thepatients are greeted in Zone II and are not free tomove throughout Zone II at will, but rather areunder the supervision of MR personnel. It is inZone II that patient histories, answers to medicalquestions, and answers to MR imaging screeningquestions are typically obtained.

Zone III This area is the region in which free access byunscreened non-MR personnel or ferromagneticobjects or equipment can result in serious injury ordeath as a result of interactions between theindividuals or equipment and the MR scanner’sparticular environment. These interactionsinclude, but are not limited to, those with the MRscanner’s static and time-varying magnetic fields.All access to Zone III is to be strictly restricted, withaccess to regions within it (including Zone IV; seebelow) controlled by, and entirely under thesupervision of, MR personnel.

Zone IV This area is the MR scanner magnet room. Zone IV,by definition, will always be located within Zone IIIbecause it is the MR magnet and its associatedmagnetic field that generates the existence ofZone III.

Reprinted with permission from Ehrenwerth et al.27

MR¼magnetic resonance.

37Anesthesia in Satellite Locations

and balance. Until the point of discharge, fall precautionsshould be kept in place.3

Since closed claims analysis ‘‘suggests that

administration of anesthesia and sedation in

remote locations is associated with a signifi-

cant risk of adverse effects,’’ it is imperative

that the anesthesiologist be particularly

attentive to patients when visual and auditory

clues of impending cardiorespiratory events

may be hindered.

CONCLUSIONS

Anesthesia in remote locations is frequently associatedwith small dark rooms, bulky older machinery, and per-sonnel who are not always familiar with emergencyequipment and procedures. It is the role of the anesthesio-logist to ensure that the patient is taken care of in a safemanner. Standard ASA monitoring, trained personnel, anda safe anesthetic plan should be in place. Patient careshould be seen as a collaborative effort with full under-standing of procedural requirements before the onset ofanesthetic administration.

Because ‘‘analysis of closed claims suggests that admin-istration of anesthesia and sedation in remote locations isassociated with a significant risk of adverse effects,’’ it isimperative that the anesthesiologist be particularly atten-tive to patients when visual and auditory clues of im-pending cardiorespiratory events may be hindered.3 Thereis substantial evidence that continuous monitoring of res-piration by capnography is extremely useful in patientsreceiving both general anesthesia and sedation. Temper-ature monitoring, though important, may be hazardous ifimproper equipment is used in some locations (e.g., MRI).The requirements of the equipment may limit the ability toadjust room temperature. Forced-air warming devices maynot be suitable in all locations, despite the desire to main-tain normothermia.

Transportation of patients, especially if significant dis-tance must be traveled to reach the recovery location,should include an oxygen cylinder, a patient monitor,emergency drugs, and a portable suction device. Post-anesthesia care may be performed in a separate locationwhen expected patient turnover and recovery times aremuch shorter.

Finally, the practicing anesthesiologist should remainfamiliar with the ASA practice guidelines, advisories, andstandards as they relate to anesthesia in remote locations. Pa-tient safety should not be compromised in remote locations.

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