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

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Flow characteristics of low concentration non-Newtonian fluid through a channel with an obstruction at the entry

The flow of Newtonian fluid (eg. water) in the test channel with an obstruction at the entrance placed in a wider channel was seen to be stagnant, forward or reverse depending on the position of the obstruction. This interesting flow phenomenon has potential benefit and can be employed in the control of energy and various flows in process engineering. This study was extended to non-Newtonian fluid for further investigation using flat plate as an obstruction. A low concentration polyacrylamide fluid solution (0.018%) showing non-Newtonian fluid behavior was used in this investigation. The parameters that affect the flow inside and around the test channel were the gap (g) between the obstruction geometry and the test channel, the Reynolds number and the length of the test channel. The maximum reverse flow inside the test channel observed was 20%-25% of the outside test channel velocity at g/w (gap to width) ratio of 1 for Reynolds number of 1000 to 3500. The results of the influence of the test channel length and the Reynolds number on the velocity ration (Vi/Vo: inside velocity/outside velocity in the test channel) is also presented and discussed

Flow of a mixed solution in a channel with obstruction at the entry : experimental and numerical investigation and comparison with other fluids

Flow in a channel with obstruction geometry at the entry placed in another wider parallel walled channel could be reverse, stagnant or forward depending on the position of the obstruction geometry. Various parameters that influence the flow inside and around the test channel are: size and shape of the obstruction geometries, gap between the test channel and the obstruction geometry, and Reynolds number. The influence of these parameters on the magnitude of the velocity ratio, Vi/Vo (inside/outside velocity of the test channel) is investigated in this study. Semicircle, circle, triangles and various shapes of rectangles were used as the obstruction geometries. A mixed solution was used for the detailed investigation of the flow phenomena and its results are compared with that of a polyacrylamide solution and water. The experimental investigations include velocity measurement and flow visualization of the two non-Newtonian fluids (mixed solution and polyacrylamide solution) and Newtonian fluid (water). The two non-Newtonian fluids have the same viscosity but show a slightly different elasticity and they follow a power-law model. The numerical simulations of the flow of the mixed solution were also carried out using the CFD-ACE+ software.The results show that the flat plate obstruction geometry produce the maximum reverse flow and it occurs at a gap to width (g/w) ratio of 1.0 for non-Newtonian fluids, and at g/w ratio of 1.5 for water. The numerical simulations show that the predicted streamlines and velocity vectors of the flow phenomena are in good agreement with the streak lines of the flow visualization images

Numerical modelling of reverse flow phenomena in a channel with obstruction geometry at the entry

Numerical modelling and simulation of the reverse flow phenomenon in a channel with obstruction geometry at the entry were performed using CFD-ACE+ simulation solver. Obstruction geometries used for simulation were triangle, circle, semicircle and flat plate. Simulations were performed for different gap to width ratio, for different gap between the test channel and obstruction geometry, and for different Reynolds number. The simulated results are discussed and compared with flow visualization images. Simulations results predicted the occurrence of reverse flow and existence of other flow features such as vortex shedding at both ends. The numerically predicted results of the flow phenomena are generally in good agreement with the experimentally observed flow visualization images

A comparative study of the flow phenomena of water and mixed solution in a channel with obstruction : influence of shapes

The effect of shapes of the obstruction geometry on the flow phenomena of a non-Newtonian mixed solution in a channel is investigated and compared with that of water (Newtonian fluid). The investigation is carried out at a fixed Reynolds number of 2000 for both the fluids. The shapes used were: flat plate, triangular, semicircular and circular. The reason for choosing a mixed solution, a non-Newtonian fluid, is that the most fluids used in industry are non-Newtonian in nature. The flow phenomena were investigated using velocity measurement (quantitative measurement) and flow visualization (qualitative measurement) images. It was found that the flat plate obstruction geometry produce the maximum reverse flow inside the test channel whereas circular obstruction geometry produce the least reverse flow

Flow of water in a channel with various obstruction geometries at the entry

Flow of water in a channel with various obstruction geometries at the entry

Flow of a low concentration polyacrylamide fluid solution in a channel with a flat plate obstruction at the entry

Flow in a channel with an obstruction at the entry can be reverse, stagnant or forward depending on the position of the obstruction. These flow phenomena have potential applications in the control of energy and various flows in process engineering. Parameters that affect this flow inside and around the test channel are the gap (g) between the obstruction geometry and the test channel, the Reynolds number (Re) and the length (L) of the test channel. The influence of these parameters on the flow behavior was investigated using a flat plate obstruction at the entry of the channel. A low concentration polyacrylamide solution (0.018% by weight) showing a powerlaw fluid behavior was used as the fluid in this investigation. The flow phenomena were investigated by the velocity measurement and the flow visualization and their results were compared with numerical simulation. These results of low concentration polyacrylamide solution are also compared with the results of water published elsewhere (Kabir et al., 2003). The maximum reverse flow inside the test channel observed was 20% - 30% of the outside test channel velocity at a g/w (gap to width) ratio of 1 for Reynolds numbers of 1000 to 3500. The influence of the test channel length (L) and the Reynolds number (Re) on the velocity ratio (Vi/Vo: inside velocity/outside velocity in the test channel) are also presented and discussed here

Flow visualisation investigation of water in a channel with flat plate obstruction geometry at the entry

Flow visualisation investigation of water in a channel with flat plate obstruction geometry at the entry

Characteristics of bubble rise in water and non-newtonian fluids

The characteristics of bubble rise phenomenon in three liquids were studied in a newly designed rig and are reported here. The experimental rig consists of two transparent cylindrical columns – one a polycarbonate tube of 125 mm diameter and the other an acrylic tube of 400 mm diameter. The rig also consists of a lifting device designed to hold a video camera for taking bubble images. Water and two non-Newtonian fluids (0.025% and 0.045% by weight of polyacrylamide solutions) were used in this study. The smaller polycarbonate tube was used to study the bubble rise characteristics namely, the velocity and the drag coefficient under vacuum. The bigger acrylic tube was used to study the influence of the size of bubbles. Keywords: vacuum pan, rising velocity, massecuite, rheology, polymeric liquids