E THE OPEN MIND

Computer-Assisted Personalized Sedation: Friend or Foe? Richard D. Urman, MD, MBA, and Walter G. Maurer, MD

A

computer-assisted personalized sedation (CAPS) device, SEDASYS® (Ethicon Endo-Surgery, a Johnson & Johnson company, Cincinnati, OH) recently received pre-market approval by the Food and Drug Administration (FDA).1 This device integrates physiologic patient monitoring and drug delivery of propofol via a computer interface. Monitoring consists of arterial blood pressure, heart rate, pulse oximetry, respiratory rate monitoring by exhaled CO2, and an automated responsiveness monitor (ARM). There is also an integrated alarm system, automated oxygen delivery that increases based on a patient’s peripheral oxygen saturation, and propofol titration based on patient responsiveness using the ARM and physiologic feedback through the other monitors.2 Designed to deliver a propofol infusion, the system is intended for moderate sedation as defined by the American Society of Anesthesiologists.3 To date, SEDASYS has only received FDA approval for routine colonoscopy and esophagogastroduodenoscopy (EGD) procedures. It is important to distinguish CAPS from other systems such as patient-controlled sedation/analgesia devices4,5 because the patient cannot directly adjust the rate of propofol infusion. In addition, it is not a target-controlled infusion device because infusion is not based on a predicted effectsite concentration. CAPS is not a closed-loop system either, because it would not automatically increase the propofol infusion but only decrease or stop it based on a patient’s physiologic response.6 Figure  1 shows all the marketed components of the SEDASYS device. Two essential components of the propofol delivery system, procedure room unit and bedside monitoring unit with patient monitoring equipment, are shown in Figure  2. The main monitoring screen as it would appear during propofol administration is shown in Figure 3. This is what the display would look like approximately 6 to 7 minutes into sedation for a hypothetical patient. In this example, the SEDASYS system is delivering a maintenance propofol infusion rate of 60 μg/kg/min (selected by the supervising physician); the patient has

already received 6 mL (60 mg) propofol. Furthermore, the patient is receiving 2 L/min oxygen, shown in the lower right corner of the screen. The patient is minimally to moderately sedated, responding to the ARM in 4 seconds. The trend line to the left of the response time button shows the history of the patient’s time to respond to the ARM queries, with each dot on the trend representing a query. The queries are done every 15 seconds during an initial loading dose and every 1 minute during the maintenance infusion. The trend provides the physician with a visual record of the patient’s sedation level over time. FDA approval variables limit device use to ASA physical status I and II patients older than 18 years, training of the responsible clinician in the management of cardiorespiratory effects of propofol, and the system only being deployed in a facility where an anesthesia professional is immediately available.7 It is not intended for high-risk

From the Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, Boston, Massachusetts; and Department of General Anesthesiology, The Cleveland Clinic Foundation, Cleveland, Ohio. Accepted for publication March 5, 2014. Funding: None. Conflicts of Interest: See Disclosures at the end of the article. Reprints will not be available from the authors. Address correspondence to Richard D. Urman, MD, MBA, Department of Anesthesiology, Perioperative and Pain Management, Brigham and Women’s Hospital/Harvard Medical School, 75 Francis St., CWN L1. Address e-mail to [email protected]. Copyright © 2014 International Anesthesia Research Society DOI: 10.1213/ANE.0000000000000268

July 2014 • Volume 119 • Number 1

Figure 1. The SEDASYS® system. www.anesthesia-analgesia.org

207

E The Open Mind

Figure 2. Major components of the SEDASYS® system: procedure room unit and bedside monitoring unit with patient monitoring.

patients such as patients with high American Society of Anesthesiologists class, morbid obesity, difficult airway or aspiration risk, or patients requiring deep sedation or general anesthesia.8 The initial dose of propofol and any increases in propofol dosing require clinician intervention. An algorithm within the device decreases the dose of propofol based on the ARM and the physiologic monitors. The system is designed to be used with a single preprocedure dose of fentanyl administered approximately 3 minutes before the initiation of the propofol infusion. Specifically, a single 50 to 100 μg fentanyl bolus should be given to patients ≤64 years of age, whereas a smaller, 25 to 50 μg bolus is intended for patients ≥65 years of age.9 In response to the FDA premarket approval in 2013, the American Society of Anesthesiologists created an ad hoc committee to understand the nature of this device and its implications for patient safety and our profession. The committee aims to work closely with the manufacturer of the device (Ethicon Endo-Surgery, a Johnson & Johnson company) and the FDA while SEDASYS is being integrated into clinical practice.1,10

DISCUSSION

The introduction of this device again raises the question about who can administer propofol: is this something that nonanesthesia professionals can do safely using this device and preset variables? Propofol offers quick onset and rapid recovery, few side effects, and has been increasing in

208    www.anesthesia-analgesia.org

popularity for endoscopic procedures. There is a long history of propofol being administered by both nurses and proceduralists who are not anesthesia professionals, with several studies reporting relatively low rates of severe adverse outcomes.11–15 At the same time, physiologic patient responses to propofol can vary significantly, and there is a real danger of progression from moderate to deep sedation and/or general anesthesia.16 As recently as 2010, the FDA turned down the request by the American College of Gastroenterology to remove the following warning label regarding who can administer propofol: “For general anesthesia or monitored anesthesia care (MAC) sedation, Diprivan Injectible Emulsion should be administered only by persons trained in the administration of general anesthesia and not involved in the conduct of the surgical/diagnostic procedure.”17 The reality is that anesthesia-administered sedation for routine endoscopy is expected to increase from 25% in 2007 to 50% of all standard endoscopies by 2015.18 The average cost for this anesthesia service is approximately $400,19 although it can vary between $200-$1000 depending on the payor mix.18 Currently, about $2 billion is spent for anesthesia services for gastrointestinal endoscopy.20 However, in the era of cost cutting and decreasing payer reimbursements, anesthesia services are perceived by some to unnecessarily inflate health care costs. In response, some insurers are instituting preauthorization requirements for anesthesia services, requiring documentation of medical necessity for

anesthesia & analgesia

Computer-Assisted Personalized Sedation

Figure 3. Details of the main monitoring screen of the SEDASYS® system.

anesthesia service, and are examining reimbursements to the gastroenterologists as a way to compensate for the skyrocketing costs of routine endoscopic procedures. On the contrary, SEDASYS also has costs associated with device implementation, staff training, costs of supplies and medications, and availabilities of anesthesia rescue services. The manufacturer’s business model is not finalized at this time. It may include a combination of fees per case (including disposables), equipment leasing, or outright purchase. It remains to be seen who would absorb this cost: the proceduralist, facility, insurer, or perhaps even the patient. This is in addition to the expense of having an anesthesia professional immediately available, as currently mandated by the FDA. Can it save money for the health care system compared to the average $400 cost for comparable anesthesia service?19 The anesthesia community raised concerns about the safety of the device specifically related to its monitoring capabilities. By the time the machine alarm sounds, the patient may already be in distress, something that an anesthesia provider would have caught earlier. Supplemental delivery of oxygen can delay the recognition of hypoventilation or an obstructed airway. Another concern was concomitant administration of other sedatives and analgesics that would exacerbate the cardiopulmonary effects of propofol. The use of a PRN button and the high maximum dose

July 2014 • Volume 119 • Number 1

of 200 μg/kg/min were also concerning to the American Society of Anesthesiologists. There is a need for more literature and randomized controlled studies evaluating the safety and effectiveness of CAPS. An initial nonrandomized study was published by Pambianco et al.21 in 2008. A second study by Pambianco et al.22 was published in 2011. This industry-sponsored, nonblinded multicenter randomized comparative study included mostly ASA physical status I to II (and a few ASA physical status III) patients undergoing routine colonoscopy or EGD. Patients were randomized to either receive sedation with SEDASYS (study group, 496 patients) or benzodiazepine/opioid combination (control group, 504 patients). The primary outcome chosen was area under the curve of oxygen desaturation (AUCDesat), a composite measure of desaturation as a function of incidence, depth, and duration of hypoxemia. The results showed that the study group had a significantly lower incidence of hypoxemia, and both groups were predominately minimally to moderately sedated. In addition, study group patients showed greater satisfaction and faster recovery, the latter finding suggesting potential cost savings associated with operating room timebased costs.23 The incidence of adverse events was reported as 5.8% compared to 8.7% in the control group, and clinicians appeared to be significantly more satisfied with the

www.anesthesia-analgesia.org

209

E The Open Mind sedation instrument in the study group. These study findings are summarized in Table 1. However, there are several limitations inherent in the study design. These include lack of capnography use in the control group and uncertainty if the difference in adverse events was statistically significant because there were still patients in the study group who inadvertently progressed to deep sedation or general anesthesia with both groups requiring airway manipulation. In addition, study personnel were not blinded, high flow oxygen used in the study group could delay detection of hypoventilation, less oxygen was used for controls, and there were large doses of midazolam and fentanyl administered to the control group. A more informative study would have been to compare outcomes from propofol administration by SEDASYS to those by a professional trained in the administration of general anesthesia. We believe that the most likely group to benefit from SEDASYS are ASA physical status I to II patients undergoing EGD and colonoscopy screening who already have failed moderate sedation with the drugs usually administered by the endoscopy team. Complex endoscopic procedures such as endoscopic retrograde cholangiopancreatography, endoscopic ultrasonography, and double-balloon endoscopy most often are lengthy, more aggressive and stimulating, and usually demand a more immobile patient. Newer and even more complex endoscopic procedures are being developed. These procedures and those patients with significant coexisting diseases are best cared for by anesthesia services. What can we conclude about the safety of the device and the introduction of this disruptive innovation to the health care market? As the debate about propofol administration by nonanesthesia professionals rages on, more high-quality, randomized prospective studies are needed to examine CAPS uses in routine clinical practice, user response to alarms,

Table 1.  Summary of Major Findings from the Study by Pambianco et al.21 2011 Outcome measure AUCDesat (s.%) Clinician satisfaction Patient satisfaction Percentage of patients recovered within 10 min Adverse event (% patients)

SEDASYS (study) group 23.6 92.2 92.3 99

5.8

Benzodiazepine/ opioid (control) group 88.0 76.3 89.7 75

8.7

P 0.028

Computer-assisted personalized sedation: friend or foe?

Computer-assisted personalized sedation: friend or foe? - PDF Download Free
881KB Sizes 4 Downloads 4 Views