A similarly designed study found a significant relative risk reduction of 49% for not only systemic complications but that of wounds as well. These call into question the role of marijuana on perioperative complications, especially when taking into consideration that the pulmonary complications in the chronic cannabis smoker are equivalents to that of a chronic tobacco smoker, probably due to the cannabis smoke products. One such pulmonary complication is airway obstruction, extensively linked to marijuana use , in which Warner et al. found that untreated, such as a lack of smoking cessation in the case of marijuana, leaves patients at a high risk for perioperative complications. When it comes to the case of cardiovascular maintenance in the perioperative period, marijuana presents complications. As mentioned previously, cannabis use can createa series of ECG changes that must be considered and monitored such as PVCs, atrial fibrillation, AV block, or Brugada-like changes. As a worst case scenario, cannabis use has been linked to plaque rupture and resultant myocardial infarction. These are all causes for concern considering that Gregg et al. reported, in conducting a series of 55 clinical trials in patients medicated with THC, that peak heart rate increased by 24.1% in surgical patients compared to the non-surgical. The authors concluded that THC may have a synergistic cardiovascular relationship with surgical stress. This tachycardia gave credence to Bryson’s recommendation that ketamine, pancuronium, atropine and epinephrine, all drugs known to affect heart rate, should be avoided in patients with history of acute marijuana use, while the bradycardia and hypotension that results from high doses of marijuana called into question the amount of atropine and vasopressors needed. Despite the impetus behind these recommendations, 1 trial showed epinephrine to have no synergistic effect with marijuana when it comes to cardiovascular effects, showing more research is needed on the potential interactions of marijuana and perioperative medications. Field visualization plays a key role in any operation.
Marijuana, however, may affect this. In a literature review published in Poland, Zakrzeska et al. explored how cannabinoids and their metabolites and their effects on the receptors CB1, CB2, CBPT and CBED as well as other systems may impact hemostasis. The authors concluded that despite the studies that have shown contradictory effects,grow tray stand based on the physiology, it is reasonable to conclude that marijuana could have an anti-hemostatic effect. Multiple studies have backed up that conclusion. In 1979, Schaeffer et al. reported that cannabis users had a diminished ability for platelet aggregation. This led to further investigations and in 1989, Formukong et al. looked at cannabinoids’ effect on platelet aggregation. The authors found that in both rabbit and human platelet aggregation that was induced by adenosine diphosphate or epinephrine was inhibited by cannabinoids in a dose-dependent manner and with cannabidiol more potent than THC in this effect. Then in 2007, an in vitro coagulation study showed that marijuana and two of the major cannabinoids, including THC, had an anticoagulant property and even more so, an antithrombotic effect. In the in vivo model testing clotting times of lean and obese rats, those treated with cannabis had clotting times 1.5 to 2 times greater than the controls, thus supporting the results of the in vitro study. In a follow-up study in 2014, the whole blood of donors who had consumed cannabis had diminished platelet aggregation. The conclusion was drawn that endocannabinoid receptor agonists reduce platelet activation as well as aggregation, and as such might have potential in antithrombotic therapies. This anticoagulatory effect could counteract the surgeon’s attempts to create hemostasis within the operative field and thus limit visualization. Yet Zakrzeska also concluded that marijuana use may put certain individuals at risk for thromboembolism, a second issue of surgical concern. Even though anintravenous injection of cannabis has been shown to cause a significant drop in the platelet count which seems in line with the belief of anticoagulation, it is the marijuana components that cause a release of ADP from erythrocyte, leading to platelet aggregation. This aggregation is the reason behind the reduction in platelet count.
The theory of marijuana use leading to platelet aggregation leads toward substantiating the conclusion Desbois et al. made in regards to an increased predilection for myocardial infarctions and arterial disease. Reports of cases similar lead to Deusch et al.’s in vitro study. The cannabinoid receptors CB1 and CB2 were found on the cell membrane of the human platelet via western blot. Delta-9- tetrahydrocannabinol, which is the ingredient within cannabis responsible for the psychological effects, demonstrated the ability to significantly increase the expression of glycoprotein IIb-IIIa as well as P-selectin thus increasing the activation of the human platelet. This findings lead to the conclusion that THC, through its effects on the cannabinoid receptors on platelets, may create a prothrombotic setting favoring the development of cardiovascular events. As surgical technique and field advance, more complicated and potentially painful procedures are becoming more common practice. Surveying patients indicated that over 80% experience postoperative pain that was rated as either moderate or severe. This pain can set off a series of physiologic changes that may harm various systems ranging from cardiovascular to the central nervous system, and has been shown to lengthen hospital stays and time to first ambulation, impede postoperative nursing and physiotherapy, increase healthcare costs, and reduce the patient’s satisfaction with the outcome. However, multiple reviews of the available literature have concluded that appropriate and adequate postoperative analgesia improves recovery, including improving cardiac function and decreasing mortality and morbidity related to pulmonary function, decreases thrombosis risk, diminishes the possibility of chronic pain syndrome, and improves overall outcome. Marijuana plays a role now in medicine as an analgesic. Prescribed for a number of diagnoses, medical marijuana has been shown in over 18 randomized trials to be both effective and safe in the treatment of chronic pain, with the best evidence being for neuropathic pain. Investigating the role marijuana plays as an analgesic, Russo found that due to cannabis’s role in multiple pathways, safety, and potential side effects and benefits shown in the clinical trials, marijuana may play a more important role in pain management when combined with opioids. However, the appropriate management of marijuana users with opioids postoperatively is more complicated than these trials suggest. In chronic marijuana users, the perioperative narcotic requirements to gain appropriate analgesia were significantly increased. Yet despite this increase, patients were more likely to subjectively experience less pain than those of their non-marijuana using counterparts.
Clinically, this increase materialized in the form of a narcotic requirement twice that of the average patient of the same height and weight each day over the course of two postoperative days, demonstrating a potential interaction between marijuana and opioids which must be taken into account when considering the potential postoperative complications that may arise from the increased doses of opioids. In a literature review published in the Journal of Obesity Surgery, Rummel et al. posed the question of whether or not marijuana use should be a contraindication to bariatric surgery. In their investigation, the authors determined that there was a lack of a generalized screening protocol for marijuana use amongst providers and thus there is no account of a known effect on procedures due to confounders. Yet, due to the many effects marijuana has on the cardiovascular, pulmonary, immunologic, and central nervous system, the conclusion was drawn that it is fair to hypothesize that cannabis use has the potential to worsen adverse outcomes in the postoperative period. These potential risks and lack of screening resulted in the recommendation that practitioners of bariatric surgery should be devoted to assessing controlled and problematic levels of preoperative substance use and take the time to discuss the potential postoperative risks with patients. However, the American Association of Clinical Endocrinologists, the Obesity Society, and the American Society for Metabolic and Bariatric Surgery took the recommendations one step further by stating that current drug use, including marijuana, should be treated as exclusionary criterion in the case of bariatric surgery. These recommendations for an elective procedure should potentially be considered in the case of all elective surgical procedures.
Hemp-lime is a bio-composite material comprised of hemp shiv, the woody core of hemp plant, and a lime based binder. The composite can be cast into any rigid form and can be used as a floor, wall or roofing material.Hemp shiv comes from renewable sources and lime is a flexible,garden racks for sale reusable and breathable material with significantly lower embodied energy than conventional masonry materials. Because of its low compressive strength, hemplime is typically used as an insulating infill material between structural framework. Hemp-lime possesses excellent hygric and moderate thermal properties. The dry thermal conductivity of hemp-lime varies between 0.06 and 0.12 W/m K. It is observed that the thermal performance of hemp-lime is better than what its U-value or thermal conductivity value suggests. This is may be because of the low thermal diffusivity of hemp-lime resulting from its high specific heat capacity, varying between 1300 and 1700 J/Kg.K, combined with its high density, ranging between 220 and 950 kg/m3. Since the external boundary conditions are dynamic, the high thermal mass of hemp-lime means that variations in changes in temperature can be dampened and the peak energy load can be reduced. In terms of hygric properties, hemp-lime, like other cellulose materials, works as an effective hygric mass because of its ‘Excellent’ moisture buffer capacity in its exposed condition. Moisture buffer capacity of a hygroscopic material enables the material to moderate the fluctuations in relative humidity of an enclosed space by utilising the adsorption and desorption properties of the material. Moisture buffering properties of the material also helps to reduce condensation in the building envelope and maintain indoor air quality. In addition to the moisture buffer capacity, moisture buffer performance of a material depends also on the exposure area, vapour permeability, surface treatment of the material, moisture load, ventilation rate, volume rate and initial humidity condition. The moisture buffer value can be classified within the ‘practical moisture buffer value classes’, consisting of the following ranges: negligible, limited, moderate, good and excellent. The moisture buffer value of exposed hemp-lime samples are reported as either ‘Good’ or ‘Excellent’ by a number of authors. Moisture buffering can directly and indirectly reduce the energy consumption of buildings. In terms of energy use, hygroscopic materials in general can reduce heating energy requirements by 2e3% and cooling energy requirements by 5e30% if integrated with a well-controlled HVAC system. High thermal and hygric inertia of hemp-lime can potentially help to moderate the effect of temperature and relative humidity fluctuations in an interior space. However, in practical applications, hemp-lime is used as a part of the building envelope system incorporating a combination of surface lining and surface treatment. The application of plaster or surface treated inner lining and the presence of a service void or air layer between the hemplime and the inner lining can potentially influence the moisture buffering ability of hemp-lime since the material is no longer in direct contact with the interior boundary conditions. Furthermore, use of coating or inner layers may delay and reduce vapour diffusion. The aim of the present study is to compare the moisture buffer values of vapour-open wall assemblies containing hemplime and inner linings and surface treatments with that of the exposed hemp-lime. The Nordtest protocol is followed to determine the moisture buffer values of the assembly. The experiments described in this article are part of the experiments being carried out in the EPSRC-funded HIVE building situated in the Building Research Park at Wroughton, UK.The samples were sealed on 5 out of 6 sides with aluminium foil tape. The upper surfaces of the assemblies were kept exposed for adsorption and desorption of moisture. The assemblies were then conditioned to 23 C temperature and 50% relative humidity to reach equilibrium moisture content in a climate chamber. The test assemblies were exposed to 75% relative humidity for 8 h and 33% relative humidity for 16 h in the climate chamber in accordance with the Nordtest Protocol. In each cycle, mass of the assemblies were measured at the end of each exposure using an analytical weighing scale with a resolution of 0.1 g. Change in moisture mass, Dm, was determined as the average of the weight gain during the moisture uptake phase of the cycle, and the weight loss during moisture release.