Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Voltage Independent Reactive Current Based Sensor for Static VAr Control Applications

The use of renewable energy-based converters is continuously increasing in modern power systems which inject voltage harmonics in the line. In this work, a novel, simple technique based on a binary (on/off) control of an analog switch is proposed to measure reactive current and reactive power. This method eliminates the requirement of finding sin( $\phi$ ) and its multiplication with the current signal in reactive power computation. The proposed transducer gives a dc signal proportional to the reactive current of a power system, i.e., ${I}$ sin( $\phi$ ), which is suitable for static VAr compensator (SVC) applications. This transducer output is sufficient as the terminal voltage is common for the measurement as well as for the compensation current. Thus, the required current of SVC for compensation is equal to or proportional to ${I}$ sin( $\phi$ ). Moreover, voltage harmonics are common in a power system. These harmonics affect the measurement of fundamental reactive power. This method eliminates the need for voltage measurement and hence the measurement is independent of the harmonics of the voltage, which reduces the measurement error. The proposed method is proved mathematically, and its performance is successfully validated through simulation analysis and hardware implementation. The advantages of the proposed technique are linearity of the transducer output, simple working, inexpensive hardware realization, fast response, and online measurement capability. The response time of the transducer is one cycle of supply voltage which is suitable for SVC applications. 2001-2012 IEEE.Scopu