On detection of spontaneous pulse by photoplethysmography in cardiopulmonary resuscitation.

OBJECTIVE: This work investigates the potential of photoplethysmography (PPG) to detect a spontaneous pulse from the finger, nose or ear in order to support pulse checks during cardiopulmonary resuscitation (CPR). METHODS: In a prospective single-center cross-sectional study, PPG signals were acquired from cardiac arrest victims who underwent CPR. The PPG signals were analyzed and compared to arterial blood pressure (ABP) signals as a reference during three distranaisco; Date: 2/2/2020; Time:18:44:23inct phases of CPR: compression pauses, on-going compressions and at very low arterial blood pressure. Data analysis was based on a qualitative subjective visual description of similarities of the frequency content of PPG and ABP waveform. RESULTS: In 9 patients PPG waveforms corresponded to ABP waveforms during normal blood pressures. During ABP in the clinically challenging range of 60 to 90 mmHg and during chest compressions and pauses, PPG continued to resemble ABP, as both signals showed similar frequency components as a result of chest compressions as well as cardiac activity. Altogether 1199 s of PPG data in compression pauses were expected to show a spontaneous pulse, of which 732 s (61%) of data were artifact-free and showed the spontaneous pulse as visible in the ABP. CONCLUSIONS: PPG signals at all investigated sites can indicate pulse presence at the moment the heart resumes beating as verified via the ABP signal. Therefore, PPG may provide decision support during CPR, especially related to preventing and shortening interruptions for unnecessary pulse checks. This could have impact on CPR outcome and should further be investigated.

The Effects of Use of a Powered and a Manual Home Oral Hygiene Regimen on Plaque and Gum Health in an Orthodontic Population.

OBJECTIVES: The objective of this study was to compare the effect of two home use oral hygiene regimens on plaque, gingivitis, and gingival bleeding on subjects undergoing orthodontic treatment with fixed appliances. METHODS: This was a randomized, parallel, single-center clinical trial. Eligible study subjects fit the following profile: age 12-65 years; nonsmoker; plaque score of = 2.0 per Bonded Bracket Index (BBI) on dentition with fixed orthodontic hardware; minimum of 10 orthodontic brackets in each arch or on all teeth from first molar to first molar; presenting with mild to moderate gingivitis, defined as a score of = 1 on at least 20 sites per Gingival Bleeding Index (GBI). Subjects with advanced periodontal disease or gingival recession were not eligible. Eligible subjects were randomized to one of two home use oral hygiene regimens: manual toothbrush plus string floss (used with a threading device) for interdental cleaning (MTF regimen); or Philips Sonicare EasyClean power toothbrush with InterCare brush head and AirFloss Pro powered device, used with BreathRx mouthrinse for interdental cleaning (Sonicare Orthodontic Regimen or SOR). All subjects brushed twice daily with standard fluoridated dentifrice and performed interdental cleaning once daily. Efficacy and safety examinations were performed at Baseline and following three and six weeks of home use of the study products, and included assessments of BBI, GBI, Modified Gingival Index (MGI), and Modified Plaque Index (MPI). RESULTS: Of 228 enrolled subjects, 223 were included in the primary analysis. For the primary endpoint, reduction in BBI score following three weeks of product use, the overall least squares (LS) mean (95% CI) reduction was 0.89 (0.84, 0.95) for SOR and 0.06 (0.01, 0.12) for MTF. Expressed as percent reduction (95% CI) from Baseline, this was 33.1% (31.1%, 35.2%) for SOR and 2.01% (-0.06%, 4.07%) for MTF. The differences between regimens were statistically significant, p < 0.0001. Statistically significant differences between regimens were observed in BBI following six weeks of product use, and also for all other efficacy variables (GBI, MGI, MPI) at Week 3 and Week 6. CONCLUSIONS: The powered oral hygiene regimen was significantly more effective than a manual regimen in reducing plaque on bracketed and non-bracketed teeth, and in reducing gingival bleeding and gingival inflammation in orthodontic subjects following three weeks of use and persisting following six weeks of use. All products were safe on oral tissues and fixed orthodontic appliances.

Waveform analysis-guided treatment versus a standard shock-first protocol for the treatment of out-of-hospital cardiac arrest presenting in ventricular fibrillation: results of an international randomized, controlled trial.

BACKGROUND: Ventricular fibrillation (VF) waveform properties have been shown to predict defibrillation success and outcomes among patients treated with immediate defibrillation. We postulated that a waveform analysis algorithm could be used to identify VF unlikely to respond to immediate defibrillation, allowing selective initial treatment with cardiopulmonary resuscitation in an effort to improve overall survival. METHODS AND RESULTS: In a multicenter, double-blind, randomized study, out-of-hospital cardiac arrest patients in 2 urban emergency medical services systems were treated with automated external defibrillators using either a VF waveform analysis algorithm or the standard shock-first protocol. The VF waveform analysis used a predefined threshold value below which return of spontaneous circulation (ROSC) was unlikely with immediate defibrillation, allowing selective treatment with a 2-minute interval of cardiopulmonary resuscitation before initial defibrillation. The primary end point was survival to hospital discharge. Secondary end points included ROSC, sustained ROSC, and survival to hospital admission. Of 6738 patients enrolled, 987 patients with VF of primary cardiac origin were included in the primary analysis. No immediate or long-term survival benefit was noted for either treatment algorithm (ROSC, 42.5% versus 41.2%, P=0.70; sustained ROSC, 32.4% versus 33.4%, P=0.79; survival to admission, 34.1% versus 36.4%, P=0.46; survival to hospital discharge, 15.6% versus 17.2%, P=0.55, respectively). CONCLUSIONS: Use of a waveform analysis algorithm to guide the initial treatment of out-of-hospital cardiac arrest patients presenting in VF did not improve overall survival compared with a standard shock-first protocol. Further study is recommended to examine the role of waveform analysis for the guided management of VF.

A user-friendly integrated monitor-adhesive patch for long-term ambulatory electrocardiogram monitoring.

BACKGROUND: Compliance to long-term ambulatory electrocardiogram monitoring is important for diagnosis in patients with cardiac arrhythmia. This requires a system with a minimal impact on daily activities. OBJECTIVE: The aim of this study was to investigate if a lightweight integrated adhesive monitor for long-term use without unacceptable adverse effects is feasible. METHODS: The participants wore either a prototype lightweight monitor or a control system for a total of up to 30 days, changing patches once (investigational device) or twice (control) weekly. Comfort, skin irritation, and impact on quality of life were recorded. RESULTS: The new monitor can be worn by most participants for periods of at least 6 days. Skin irritation and comfort rating were comparable, and impact on the quality of life was low compared with the control. Patients considered the device comfortable. CONCLUSION: An integrated adhesive monitor that can be worn on the skin up to 7 days with minimal side effects is feasible.

Detection of ventricular ectopy by a novel miniature electrocardiogram recorder.

BACKGROUND: The ability of a miniaturized, skin-attached, 3-channel electrocardiogram (ECG) recorder prototype to detect ventricular ectopic beats (VEBs) and ventricular fibrillation (VF) was compared with that of standard Holter ECG. METHODS: Concurrent 15-hour ECG recordings were made in 143 patients using an experimental device provided by Philips Healthcare (Seattle, WA) and a commercially available Holter recorder. In a consensus review process, 3 physicians (M.L., A.J., and A.G.), blinded for the recording device, analyzed 1804 seven-second strips for total number of VEBs, total number of their QRS configurations, and presence of VF. Agreement between the experimental and standard devices was calculated using Spearman correlation coefficients. RESULTS: There was 100% agreement regarding VF recognition. Spearman correlation coefficients were 0.98 (P < .001) for the total number of VEBs and 0.91 (P < .001) for the total number of QRS configurations. CONCLUSIONS: The accuracy of the experimental miniaturized ECG recorder for detecting ventricular activity was found to be high. This finding could be of clinical importance.

Polarity effect in electrovibration for tactile display.

Electrovibration is the tactile sensation of an alternating potential between the human body and a smooth conducing surface when the skin slides over the surface and where the current is too small to stimulate sensory nerves directly. It has been proposed as a high-density tactile display method, for example to display pictographic information to persons who are blind. Previous models for the electrovibration transduction mechanism are based on a parallel-plate capacitor in which the electrostatic force is insensitive to polarity. We present experimental data showing that electrovibratory perceptual sensitivity to positive pulses is less than that for negative or biphasic pulses and propose that this disparity may be due to the asymmetric electrical properties of human skin. We furthermore propose using negative pulses for insulated tactile displays based on electrovibration because their sensory thresholds were found to be more stable than for waveforms incorporating positive pulses.

Towards an algorithm for automatic accelerometer-based pulse presence detection during cardiopulmonary resuscitation.

Manual palpation is still the gold standard for assessment of pulse presence during cardiopulmonary resuscitation (CPR) for professional rescuers. However, this method is unreliable, time-consuming and subjective. Therefore, reliable, quick and objectified assessment of pulse presence in cardiac arrest situations to assist professional rescuers is still an unmet need. Accelerometers may present a promising sensor modality as pulse palpation technology for which pulse detection at the carotid artery has been demonstrated to be feasible. This study extends previous work by presenting an algorithm for automatic, accelerometer-based pulse presence detection at the carotid site during CPR. We show that accelerometers might be helpful in automated detection of pulse presence during CPR.