Comparing the compensatory reserve metric obtained from invasive arterial measurements and photoplethysmographic volume-clamp during simulated hemorrhage.

PURPOSE: The compensatory reserve metric (CRM) is a novel tool to predict cardiovascular decompensation during hemorrhage. The CRM is traditionally computed using waveforms obtained from photoplethysmographic volume-clamp (PPGVC), yet invasive arterial pressures may be uniquely available. We aimed to examine the level of agreement of CRM values computed from invasive arterial-derived waveforms and values computed from PPGVC-derived waveforms. METHODS: Sixty-nine participants underwent graded lower body negative pressure to simulate hemorrhage. Waveform measurements from a brachial arterial catheter and PPGVC finger-cuff were collected. A PPGVC brachial waveform was reconstructed from the PPGVC finger waveform. Thereafter, CRM values were computed using a deep one-dimensional convolutional neural network for each of the following source waveforms; (1) invasive arterial, (2) PPGVC brachial, and (3) PPGVC finger. Bland-Altman analyses were used to determine the level of agreement between invasive arterial CRM values and PPGVC CRM values, with results presented as the Mean Bias [95% Limits of Agreement]. RESULTS: The mean bias between invasive arterial- and PPGVC brachial CRM values at rest, an applied pressure of -45mmHg, and at tolerance was 6% [-17%, 29%], 1% [-28%, 30%], and 0% [-25%, 25%], respectively. Additionally, the mean bias between invasive arterial- and PPGVC finger CRM values at rest, applied pressure of -45mmHg, and tolerance was 2% [-22%, 26%], 8% [-19%, 35%], and 5% [-15%, 25%], respectively. CONCLUSION: There is generally good agreement between CRM values obtained from invasive arterial waveforms and values obtained from PPGVC waveforms. Invasive arterial waveforms may serve as an alternative for computation of the CRM.

AI-Enabled Advanced Development for Assessing Low Circulating Blood Volume for Emergency Medical Care: Comparison of Compensatory Reserve Machine-Learning Algorithms.

The application of artificial intelligence (AI) has provided new capabilities to develop advanced medical monitoring sensors for detection of clinical conditions of low circulating blood volume such as hemorrhage. The purpose of this study was to compare for the first time the discriminative ability of two machine learning (ML) algorithms based on real-time feature analysis of arterial waveforms obtained from a non-invasive continuous blood pressure system (Finometer®) signal to predict the onset of decompensated shock: the compensatory reserve index (CRI) and the compensatory reserve metric (CRM). One hundred ninety-one healthy volunteers underwent progressive simulated hemorrhage using lower body negative pressure (LBNP). The least squares means and standard deviations for each measure were assessed by LBNP level and stratified by tolerance status (high vs. low tolerance to central hypovolemia). Generalized Linear Mixed Models were used to perform repeated measures logistic regression analysis by regressing the onset of decompensated shock on CRI and CRM. Sensitivity and specificity were assessed by calculation of receiver-operating characteristic (ROC) area under the curve (AUC) for CRI and CRM. Values for CRI and CRM were not distinguishable across levels of LBNP independent of LBNP tolerance classification, with CRM ROC AUC (0.9268) being statistically similar (p = 0.134) to CRI ROC AUC (0.9164). Both CRI and CRM ML algorithms displayed discriminative ability to predict decompensated shock to include individual subjects with varying levels of tolerance to central hypovolemia. Arterial waveform feature analysis provides a highly sensitive and specific monitoring approach for the detection of ongoing hemorrhage, particularly for those patients at greatest risk for early onset of decompensated shock and requirement for implementation of life-saving interventions.

Axonics Sacral Neuromodulation System for Treating Refractory Overactive Bladder: A NICE Medical Technologies Guidance.

The Axonics sacral neuromodulation (SNM) system can be used by people with refractory overactive bladder (OAB) to reduce symptoms of urge urinary incontinence and urinary frequency, where conservative treatments have failed or are not suitable. It is the first system for this indication that makes use of a rechargeable battery to prolong the lifespan of the implanted device, with the potential advantage of reducing the frequency of surgical replacement procedures and associated complications. We describe the evidence considered by the UK National Institute of Health and Care Excellence (NICE) in their evaluation of this evidence, supported by Cedar Healthcare Technology Research Centre. Two observational studies provided descriptive data that suggested improvement in control of symptoms after implantation of the Axonics SNM system; however, there was no peer-reviewed evidence that directly compared rechargeable and non-rechargeable SNM systems. In the absence of long-term data, economic modelling relies on the accuracy of battery life estimates. The evidence supports the case for adopting the Axonics SNM system for treating refractory OAB, when conservative treatment or treatment with medicines has not worked. This conclusion is consistent with other relevant NICE guidelines. Use of Axonics SNM technology in the UK National Health Service (NHS) is associated with a potential cost saving of £6025 per person over a 15-year period when compared with an equivalent non-rechargeable SNM system, assuming the claimed battery life estimate (a minimum of 15 years) is accurate. The cost savings are estimated to start around 6 years after implantation.

Normothermic Insufflation to Prevent Perioperative Hypothermia and Improve Quality of Recovery in Elective Colectomy Patients: Protocol for a Randomized Controlled Trial.

BACKGROUND: Perioperative hypothermia during laparoscopy for bowel resection is a risk factor for postoperative medical complications and surgical wound infections. Despite various warming methods used during surgery, a significant number of patients experience perioperative hypothermia. Use of dry, unwarmed insufflation carbon dioxide (CO2) during laparoscopic procedures may contribute to this problem. Evidence exists that the HumiGard device, which humidifies and heats CO2 for insufflation, can reduce the risk of perioperative hypothermia. OBJECTIVE: The aim is to determine if insufflation with warmed, humidified CO2 using the HumiGard device, alongside standard perioperative warming techniques, can improve patient recovery, including pain, surgical site infections, complications, and the use of analgesia compared with standard care alone. METHODS: The study is a multicenter, randomized, blinded (patient, surgeon, and assessor), sham device-controlled, parallel group-controlled trial of 232 patients. The study aims to recruit patients undergoing elective laparoscopic, segmental, or total colectomy. Patients will be randomized to receive HumiGard plus standard care or standard care alone (1:1 ratio). The primary outcome is patient-reported quality of recovery, measured by the validated QoR-40 (quality of recovery) questionnaire, from baseline to postoperative day 1. Secondary outcomes include postoperative pain, the incidence of hypothermia, and the rate of postoperative complications. RESULTS: The information gathered during a small-scale service evaluation at a single hospital was used to inform this study protocol. Before applying for a grant for this full randomized controlled trial, the authors will conduct a feasibility study of 40 patients to ensure that the protocol is feasible and to inform our sample size calculation. CONCLUSIONS: The randomized controlled trial is designed to provide high-quality evidence on the effectiveness of the HumiGard device in potentially reducing the risk of perioperative hypothermia in patients scheduled for laparoscopic colectomy. The results will be used to improve the maintenance of adequate patient body temperature during surgery. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/14533.

Partnership working with independent providers.

The Department of Health in England want to see NHS commissioners and providers capitalize upon the expertise of the independent sector for the benefit of NHS patients. In preparing for the future what does the sector have to offer NHS nurses and how will this benefit patient care? This paper examines the role of independent providers and the way they are helping NHS commissioners and providers to break new ground in delivering more accessible and convenient care for NHS patients at home.

Safety and pharmacokinetics of chimeric anti-Shiga toxin 1 and anti-Shiga toxin 2 monoclonal antibodies in healthy volunteers.

Shiga toxin (Stx)-producing Escherichia coli (STEC) causes hemorrhagic colitis and hemolytic-uremic syndrome (HUS). The rates of STEC infection and complications, including death, are highest among young children and elderly individuals. There are no causal therapies. Because Stx is the primary pathological agent leading to organ injury in patients with STEC disease, therapeutic antibodies are being developed to neutralize systemically absorbed toxin during the early phase of the infection. Two phase I, single-dose, open-label, nonrandomized studies were conducted to evaluate the safety and pharmacokinetics of the chimeric monoclonal antibodies (antitoxins) against Stx 1 and 2 (calphaStx1 and calphaStx2, respectively). In the first study, 16 volunteers received 1 or 3 mg/kg of body weight of calphaStx1 or calphaStx2 as a single, short (1-h) intravenous infusion (n = 4 per group). In a second study, 10 volunteers received a 1-h infusion of calphaStx1 and calphaStx2 combined at 1 or 3 mg/kg (n = 5 per group). Treatment-emergent adverse events were mild, resolved spontaneously, and were generally unrelated to the antibody infusion. No serious adverse events were observed. Human antichimeric antibodies were detected in a single blood sample collected on day 57. Antibody clearance was slightly greater for calphaStx1 (0.38 +/- 0.16 ml/h/kg [mean +/- standard deviation]) than for calphaStx2 (0.20 +/- 0.07 ml/h/kg) (P = 0.0013, t test). The low clearance is consistent with the long elimination half-lives of calphaStx1 (190.4 +/- 140.2 h) and calphaStx2 (260.6 +/- 112.4 h; P = 0.151). The small volume of distribution (0.08 +/- 0.05 liter/kg, combined data) indicates that the antibodies are retained within the circulation. The conclusion is that calphaStx1 and calphaStx2, given as individual or combined short intravenous infusions, are well tolerated. These results form the basis for future safety and efficacy trials with patients with STEC infections to ameliorate or prevent HUS and other complications.

Vibration characteristics of dental high-speed turbines and speed-increasing handpieces.

OBJECTIVES: Vibrations of dental handpieces may contribute to symptoms of hand-arm vibration syndrome in dental personnel and iatrogenic enamel cracking in teeth. However, methods for measuring dental handpiece vibrations have previously been limited and information about vibration characteristics is sparse. This preliminary study aimed to use a novel approach to assess the vibrations of unloaded high-speed handpieces in vitro. METHODS: Maximum vibration displacement amplitudes of five air turbines and two speed-increasing handpieces were recorded whilst they were operated with and without a rotary cutting instrument (RCI) using a scanning laser vibrometer (SLV). RESULTS: RCI rotation speeds, calculated from frequency peaks, were consistent with expected values. ANOVA statistical analysis indicated significant differences in vibrations between handpiece models (p<0.01), although post hoc tests revealed that differences between most individual models were not significant (p>0.11). Operating handpieces with a RCI resulted in greater vibrations than with no RCI (p<0.01). Points on the head of the handpiece showed greater vibration displacement amplitudes than points along the body (p<0.01). CONCLUSIONS: Although no single measurement exceeded 4 microm for the handpieces in the current test setup (implying that these vibrations may be unlikely to cause adverse effects), this study has formed the basis for future work which will include handpiece vibration measurements whilst cutting under clinically representative loads.