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

Load, Speed and Temperature Sensitivities of a Carbon-Fiber-Reinforced Phenolic Friction Material

A model friction material was formulated with a cashew-modified phenolic resin, short carbon fiber, phenolic particles, barytes and steel fiber. The friction, wear and fade characteristics of this material were determined using a Chase friction material testing machine. The coefficient of friction was found to vary between 0.2 and 0.5 with lower values associated with higher loads, speeds and drum temperatures and vice versa. Conditioning the specimens with several fade-recovery test cycles resulted in steady friction during subsequent fade tests followed by excellent recovery characteristics. The specific wear rate per unit load and sliding distance decreased with increasing loads, but increased with increasing drum speeds and temperatures due to thermal degradation of the resin. The carbon-fiber-reinforced friction material showed lower specific wear rates than that of a milled-glass-fiber-based friction material at low speeds and temperatures over a wide load range. © 1995

Fade and Wear Characteristics of a Glass-Fiber-Reinforced Phenolic Friction Material

The fade and wear characteristics of a glass-fiber-reinforced friction material were studied using a Chase friction material testing machine. At low counterface temperatures, the friction material showed relatively high friction in the range 0.4-0.5. During fade tests, the coefficient of friction dropped to about 0.18 at 343 °C. Re-conditioning the wear surface at the end of a fade test altered the frictional behavior during a subsequent fade test. The wear tests showed that the specific weight loss per unit load and sliding distance decreases with increasing applied load and speed, but increases with increasing bulk drum temperature. At high temperatures, thermochemical degradation and fiber pull-out appear to contribute to higher specific wear rate. The worn surfaces of the specimens were observed by scanning electron microscopy and analyzed by energy-dispersive X-ray analysis. The results were consistent with low friction coefficients due to film formation on the worn surfaces of glass fiber at high temperatures. This film could be removed at lower temperatures by either sliding (application) or by sanding. © 1994

Hybrid Phenolic Friction Composites Containing Kevlar® Pulp. Part II - Wear Surface Characteristics

The wear surfaces of control (without Kevlar®) and hybrid (with Kevlar®) phenolic composites were analyzed using a scanning electron microscope and energy dispersive X-rays to determine the influence of Kevlar® pulp on the wear surface morphologies at various sliding conditions. At a high sliding speed of 11.2 m s-1, the wear surface of a control glass fiber composite showed the formation of a nearly continuous and homogeneous film comprised of elements from the counterface and the composite itself. This film did not appear to form in a glass-Kevlar® hybrid composite at a similar operating speed. At 11.2 m s-1, a control steel fiber composite was found to wear due to a predominantly abrasive mechanism, while this mechanism was diminished in a steel-Kevlar® hybrid composite

Fracture Behaviour of Chopped Glass Strand Reinforced Phenolic Composites

Modified phenolic composites were fabricated by compression moulding a mixture of chopped glass strands and a cashew nut shell liquid modified phenolic resin. Single edge notched bend (SENB) tests, double edge notched (DEN) tension tests and 3-point flexure tests on unnotched specimens were conducted at various fibre volume fractions and strand lengths. The candidate stress intensity factors of SENB specimens were significantly higher than those of DEN specimens. Glass strand/phenolic interface debonding and strand pull-out were observed for both SENB and DEN specimens. In addition, the DEN specimens exhibited a considerable degree of splitting of glass strands parallel to their axes. By increasing the fibre volume fraction and the strand length, it was possible to improve the flexural strength without adversely affecting the fracture toughness

Bundle-Debond Technique for Characterization of Moisturized Kevlar/Phenolic Interfaces

An experimental technique called bundle-debond, is used to study the effect of water on the debonding of kevlar fiber bundles and phenolic matrix. The specimen is double notched with a single layer of kevlar fibers in between the notches. Load transfer between the top and bottom piece of the specimen occurs through the interface of a single layer of fibers. Two additional fiber layers are inlaid on the faces of the specimen in order to prevent possible tensile failure of the matrix. An accelerated test is conducted to study the effect of water on the fiber/matrix interface. The notched specimens are boiled in water for 24 hrs. Tensile loads are applied on the specimen resulting in interfacial debond. The experimental data are analyzed using a simple shear-lag theory. It is found that the interfacial shear strength of kevlar/phenolic reduced by about 12% due to absorption of water. The strain energy density of the interface is approximately 8 times lower than that of the pure matrix at failure

Hybrid Phenolic Friction Composites Containing Kevlar® Pulp. Part I - Enhancement of Friction and Wear Performance

The friction and wear characteristics of control (without Kevlar® pulp) and hybrid (with Kevlar® pulp) phenolic composites containing milled E-glass or steel were determined at various counterface speeds and temperatures using a Chase friction tester. In general, Kevlar® pulp significantly improved the wear resistance and decreased the coefficient of friction for both types of hybrid composites. Kevlar® pulp also imparted excellent frictional stability at high speeds in steel-fiber composites and significantly reduced higher frequency (\u3e5 kHz) noise at high speeds in both steel and glass-fiber composites. The stabilization of the coefficient of friction and reduction of noise was not due to the reduction of the coefficient of friction because it also occurred at constant frictional force. The addition of Kevlar® pulp to a steel-fiber-containing formulation significantly improved its overall performance

“Bundle-Debond” Technique for Characterizing Fibre/Matrix Interfacial Adhesion

An experimental technique called bundle-debonding, has been developed for characterizing the interfacial adhesion of fibre bundles and matrix. The specimen is double-notched and contains a partially embedded fibre layer in between the notches. When a tensile load is applied at the specimen ends, the load transfer across the notch and between two pieces of matrix, occurs through the interface between a single layer of fibres and matrix. Kevlar-29 (Kelvar is a registered trademark of E.I. duPont de nemours) fibre tows were used in conjunction with a solid phenolic resin to fabricate the specimens. Experiments were conducted at various embedded lengths resulting in interfacial debond. A simple shear-lag analysis was carried out to determine the interfacial shear strength. The interfacial shear strength of Kevlar-29/phenolic resin has been determined to be 15 MPa. This technique is promising for application on several fibre/matrix systems, specially for fibres of extremely low nominal diameter, supplied as tows. © 1994 Chapman & Hall

Thraustochytrids of Mangrove Habitats from Andaman Islands: Species Diversity, PUFA Profiles and Biotechnological Potential

Thraustochytrids are the most promising microbial source for the commercial production of docosahexaenoic acid (DHA) for its application in the human health, aquaculture, and nutraceutical sectors. The present study isolated 127 thraustochytrid strains from mangrove habitats of the south Andaman Islands, India to study their diversity, polyunsaturated fatty acids (PUFAs), and biotechnological potential. The predominant strains were identified as belonging to two major genera (Thraustochytrium, Aurantiochytrium) based on morphological and molecular characteristics. The strain ANVKK-06 produced the maximum biomass of 5.42 g·L−1, while ANVKK-03 exhibited the maximum total lipid (71.03%). Omega-3 PUFAs such as eicosapentaenoic acid (EPA) accumulated up to 11.03% in ANVKK-04, docosapentaenoic acid (DPA) up to 8.65% in ANVKK-07, and DHA up to 47.19% in ANVKK-06. ANVKK-06 showed the maximum scavenging activity (84.79 ± 2.30%) while ANVKK-03 and ANVKK-10 displayed the highest antibacterial activity against human and fish pathogens, S. aureus (18.69 ± 1.2 mm) and V. parahaemolyticus (18.31 ± 1.0 mm), respectively. All strains were non-toxic as evident by negative blood agar hemolysis, thus, the thraustochytrids are suggested to be a potential source of DHA for application in the health care of human and fish