RF Surgical Sponge-Detecting System on the Function of Pacemakers and Implantable Cardioverter Defibrillators (RF)

RF Surgical Sponge-Detecting System on the Function of Pacemakers and Implantable Cardioverter Defibrillators

Compatibility of Radiofrequency Detection Technology With Cardiac Internal Electronic Devices (RF Assure Study)

If a surgical sponge is mistakenly left inside a patient's body after a surgical procedure, it can cause a serious infection. To prevent this from happening, a new device has been developed that uses radiofrequency (RF) signals to detect the presence of surgical sponges inside the body. The device is now being used routinely to make sure that no sponges are left inside a patient at the end of an operation. However, the RF device has not been implemented in procedures for patients with cardiac implantable electronic devices (CIEDs). While the device is FDA approved for use, there is a theoretical concern that the radiofrequency signals used to detect the sponges will change the settings on the pacemaker or the defibrillator. Changing the settings on a pacemaker might make it pace the heart too quickly or too slowly, while changing the settings on a defibrillator might cause unnecessary shocks or prevent it from shocking the heart if the patient were to have cardiac arrest. The purpose of this study is to test whether the radiofrequency device used to detect sponges can cause a clinically significant change to the settings on pacemakers and defibrillators. To minimize potential risk, the device will be tested only on patients who are having the pacemaker or defibrillator removed or replaced as part of their regular medical care, either because it is infected or because the battery has worn out. Before the pacemaker or defibrillator is removed, the settings will be carefully and completely recorded and the radiofrequency device will be used to scan the body for sponges as it would be done during normal operation. After the pacemaker or defibrillator is taken out, the settings will again be recorded and compared to the settings before the scan. In a standard device removal procedure, no clinically significant change in CIED settings would be expected. If a new pacemaker or defibrillator is implanted in the patient, it will not be exposed to the detection device at all. We will also test whether the RF device has any effect on temporary pacemakers that patients may receive after open heart surgery. We plan to perform testing in a total of 50 patients, 40 with permanent pacemakers or defibrillators and 10 with temporary pacemakers.

Retained surgical items (e.g., sponges, needles, and instruments) are among the most frequently reported medical errors and occur in an estimated 1 in 5000 operations. A retained surgical item frequently causes a serious negative outcome, including re-operation (70-80% of cases), readmission or prolonged hospital stay (30-60% of cases), sepsis (43% of cases), or death (2% of cases). Retained surgical items are classed as "never events" by the Centers for Medicare and Medicaid Services (CMS), and CMS does not reimburse for additional medical care related to the treatment for such a complication. Sponges are by far the most common retained items and are estimated to account for 50-70% of cases. The standard method to ensure that no sponge is left inside the body is manual counting. Manual counting, however, carries a sensitivity and specificity of only about 77% and 99%, respectively. In one study 62% of retained items were detected after the count was reported as normal. If the manual count suggests that a sponge has been retained, the standard method to detect it is by taking a radiograph. Radiographs, however, are time-consuming and in one large retrospective study failed to detect retained items in 33% of cases. The standard methods of detecting retained surgical sponges are clearly suboptimal. Radiofrequency (RF) technology has recently been employed to improve the detection of retained surgical sponges. A radiofrequency chip is sewn into the fabric of the sponge, and a circular wand that emits a radiofrequency signal is passed over the patient. The wand also serves as an antenna that detects a return signal from the chip in the sponge. If a chip is detected it triggers an audio and a visual alarm on a console attached to the wand. In a study involving 210 patients, RF detection systems had 100% sensitivity and specificity for detecting retained sponges, even in morbidly obese patients. To minimize human error during the scanning process, a new system has been developed where the patient lies on a mat that emits the RF signal and serves as the antenna. In a separate study involving 203 patients, the system using the RF mat had a sensitivity and specificity of 98.5% and 100% respectively. To carry out these studies, sponges were placed underneath patients in a blinded manner. Although it would seem that RF detection systems are superior to manual counting, it should be emphasized that an RF detection system is not a substitute for manual counting, but rather an adjunct to manual counting. The RF Assure ® Detection System manufactured by RF Surgical System Inc. is now routinely used to detect retained sponges in the operating rooms at the University of California, San Diego (UCSD) and at ~200 other hospitals. There has been some concern that the radio frequency signals emitted by the RF Assure® device might reprogram the settings on CIED such as pacemakers and internal cardiac defibrillators (ICDs), since CIEDs are commonly programmed remotely using RF signals. For this reason, the technology is not commonly used in surgeries with patients with CIEDs. In vitro testing was done in a controlled setting to assess the compatibility of the RF Surgical Detection Technology with permanent pacemakers and ICDs as well as temporary pacemakers, specifically the Boston Scientific Cognis, St. Jude Medical Promote, and Medtronic Virtuoso devices, finding no interference between the RF Assure® system and these devices. Although anecdotal experience and in vitro testing has indicated that the RF Assure® system does not affect CIEDs, it has not been established whether the RF Assure® system is suitable to use in patients with CIEDs in a clinical setting. The purpose of this study is to determine whether the RF Assure® device actually can reprogram CIEDs or cause them to malfunction when used in routine clinical practice. This question is of particular importance because of the rising number of surgical patients, especially cardiac patients, that have an implanted CIED.

CIED, pacemaker, implantable cardioverter defibrillator, ICD, radiofrequency, cardiac device programming, RF sponge detection, RF assure, cardiac internal electronic devices, temporary pacing, pulmonary thromboendarterectomy, pacing interference, Arrhythmia

The patient's CIED will be interrogated prior to the study to obtain a baseline reading. The patient will be asked to lie down on the RF Assure® Detection Mat with a sponge placed underneath his or her shoulder. The RF Assure® mat and wand will be activated to detect the sponge. The sponge will be removed from underneath the patient's shoulder, and the RF system will be re-activated to obtain a clear reading. The patient's CIED will be re-interrogated to determine if the RF Assure system caused any changes to the CIED parameters or function.

CIED and temporary pacemaker patients will be scanned with RF surgical sponge detection wand and mat as well as with and without the RF sponge. The scanning will only be conducted on the device scheduled for removal. Patients will have device interrogated before and after scanning (for CIEDs) to determine if there have been any clinically significant changes in programming or settings due to scanning with RF technology. Vitals will be monitored and recorded before, during, and after scanning.

Pacing Mode Changes Between Permanent Pacemakers (PPMs)/Implantable Cardiac Defibrillators (ICDs) Scanned With RF Assure

The Pacing Mode on the CIED was measured prior to RF scanning (with sponge) and after the scanning (after sponge removal) in order to evaluate if any significant changes in the pacing mode setting resulted. The following CIED modes were evaluated: DDD (dual chamber pacing, sensing, triggered and inhibited mode), VVI (ventricular pacing, sensing, and inhibited mode), DDI (dual pacing, sensing, and inhibited mode), AAI (atrial pacing, sensing, and inhibited mode). The number of patients' device mode switched between these settings was tabulated and is shown in the below table. Multiple post-scan assessments were not made.

Pacing Polarity Changes With Permanent Pacemakers (PPMs)/Implantable Cardiac Defibrillators (ICDs) Scanned With RF Assure

The patient's pacing polarity was measured prior to scanning with sponge and after scanning with sponge via device interrogation. The following pacing polarity measurements were evaluated: right atrium/right ventricle (RA/RV) bipolar polarity, left ventricle (LV) bipolar polarity, and left ventricle (LV) unipolar polarity. Note that not all study patients had LV leads implanted. Multiple post-scan assessments were not made.

Base Rate Measurement Changes With Permanent Pacemakers (PPMs)/Implantable Cardiac Defibrillators (ICDs) Scanned w/ RF Assure

The base rate on patients' devices was measured before scanning with sponge and after RF scanning with sponge. The median was determined and is presented below with standard deviation for both times. Multiple post-scan assessments were not made.

Max Tracking Rate Changes With Permanent Pacemakers (PPMs)/Implantable Cardiac Defibrillators (ICDs) Scanned With RF Assure

The max tracking rate on the CIEDs was measured prior to scanning with the sponge and post scanning with sponge. The max tracking rate is the maximum atrial rate at which a pacemaker will deliver a ventricular pacing stimulus following each sensed atrial beat. Below, the median and standard deviation are presented. Please note that multiple post-scan assessments were not made for any patient.

Atrio-ventricular (AV) Delay Changes With Permanent Pacemakers (PPMs)/Implantable Cardiac Defibrillators (ICDs) Scanned With RF Assure

The atrio-ventricular delay was measured prior to scanning with sponge and post RF scanning with sponge. Please note that multiple post-scan assessments were not made for any of the patients presented here.

Battery Capacity Changes With Permanent Pacemakers (PPMs)/Implantable Cardiac Defibrillators (ICDs) Scanned With RF Assure

Of the patients enrolled, battery capacity changes were measured prior to and post RF scanning with sponge. Multiple post-scan assessments were not made for any of the patients presented here.

Pacing Impedance Changes With Permanent Pacemakers (PPMs)/Implantable Cardiac Defibrillators (ICDs) Scanned With RF Assure

The impedance values of right ventricle (RV), right atrium (RA), and left ventricle (LV) leads was measured prior to RF scanning with sponge and post RF scanning with sponge. Multiple post-scan assessments were not made for any patient represented here.

The shock impedance changes were measured (right ventricle (RV) coil and superior vena cava (SVC) coil) prior to and post RF scanning with sponge. This was measured by performing a device interrogation in the electrophysiology (EP) lab. Multiple post-scan measurements were not taken for any of the patients presented here.

Changes in P & R Wave Measurements in Permanent Pacemakers (PPMs)/Implantable Cardiac Defibrillators (ICDs) Scanned With RF Assure

The P and R waves were measured via device interrogation prior to and post RF scanning with sponge. Multiple post-scan measurements were not made for any of the participants represented here.

Capture Threshold Changes With Permanent Pacemakers (PPMs)/Implantable Cardiac Defibrillators (ICDs) Scanned With RF Assure

Via device interrogation, capture threshold changes (the minimum amount of electricity that the box has to emit to pace the heart) were measured prior to and post RF Scanning with sponge. Multiple post-scan measurements were not taken for any participants presented here.

Inclusion Criteria: Patients must be at least 18 years of age Patients must be willing and able to provide consent Patients must be eligible for pacemaker/ICD removal or temporary pacemaker Exclusion Criteria: Pregnancy Inability or unwillingness to comply with the protocol Medical condition that would limit study participation

Cima RR, Kollengode A, Garnatz J, Storsveen A, Weisbrod C, Deschamps C. Incidence and characteristics of potential and actual retained foreign object events in surgical patients. J Am Coll Surg. 2008 Jul;207(1):80-7. doi: 10.1016/j.jamcollsurg.2007.12.047. Epub 2008 May 23.

Egorova NN, Moskowitz A, Gelijns A, Weinberg A, Curty J, Rabin-Fastman B, Kaplan H, Cooper M, Fowler D, Emond JC, Greco G. Managing the prevention of retained surgical instruments: what is the value of counting? Ann Surg. 2008 Jan;247(1):13-8. doi: 10.1097/SLA.0b013e3180f633be.

Gawande AA, Studdert DM, Orav EJ, Brennan TA, Zinner MJ. Risk factors for retained instruments and sponges after surgery. N Engl J Med. 2003 Jan 16;348(3):229-35. doi: 10.1056/NEJMsa021721.

Steelman VM, Alasagheirin MH. Assessment of radiofrequency device sensitivity for the detection of retained surgical sponges in patients with morbid obesity. Arch Surg. 2012 Oct;147(10):955-60. doi: 10.1001/archsurg.2012.1556.

Steelman VM. Sensitivity of detection of radiofrequency surgical sponges: a prospective, cross-over study. Am J Surg. 2011 Feb;201(2):233-7. doi: 10.1016/j.amjsurg.2010.05.001.