Cent Oxygen Research Articles

Effects of intravenous lignocaine on anaesthetic parameters in cattle under dexmedetomidine-butorphanol-ketaminemidazolam- isofluraneanaesthesia

The present study was conducted for clinical evaluation of a multimodal anaesthetic protocol using butorphanol-dexmedetomidine-midazolam-ketamine-isoflurane and lignocaine continuous rate infusion (CRI) in six cross-bred female cattle. Preanaesthetics used were butorphanol and dexmedetomidine which were administered intravenously at dose rates of 0.05 mg/kg and 1 μg/ kg body weight, respectively. Ketamine and midazolam were intravenously administered at dose rates of 4.0 and 0.2 mg/kg body weight respectively, to induce anaesthesia. Isoflurane was used to maintain anaesthesia after endotracheal intubation, at a concentration of 1.05 ± 0.97 per cent concentration in 100 per cent oxygen using a large animal anaesthesia machine. Simultaneously, intravenous lignocaine was administered at a bolus dose of 2 mg/kg body weight followed by a CRI of 3 mg/kg body weight/hour using a volumetric infusion pump. Isoflurane sparing effect of intravenous lignocaine reduced the required concentration of isoflurane for maintenance. The third plane of surgical anaesthesia was maintained and various surgical procedures were done. Recovery was smooth. Other than the mild regurgitation of ruminal fluid in an animal, no anaesthetic complications were noticed.

Fulvic acid isolation and characterisation from water of a Ramsar Lake Mansar, J&K, India

The present study was undertaken with the aim to understand the chemical properties of aquatic fulvic acid in a clear water Lake Mansar. Along with that, the physical and chemical environment of the lake was also analysed. Fulvic acid was isolated from the water of Lake Mansar following IHSS recommended methodology and was subjected to characterisation, viz. elemental analysis, H-NMR and FTIR spectroscopy. The yield of fulvic acid from water of Lake Mansar was 0.22 mg/L that was far less than coloured aquatic systems. Elemental analysis revealed per cent carbon, hydrogen, nitrogen and oxygen content to be 53.6%, 5.04%, 6.3% and 35.06%, respectively. H-NMR and FTIR spectra revealed the presence of various functional groups like aliphatic, hydroxyl, amide, quinones, ketones, carbonyl, cellulose, etc. Based on the present studies, it was concluded that the origin of humic material in Lake Mansar is mostly from algae and non-vascular plants that have undergone less degree of humification.

Rapid Acclimatisation to High Altitude by Intermittent Hypoxia Training at Sea Level Role of Biochemical Markers

Rapid induction of soldiers to high altitude under emergency situation may lead to higher incidence of acute mountain sickness (AMS) and other high altitude illness. Intermittent Hypoxia Training (IHT) at sea level before going to high altitude is an approach for rapid acclimatisation. This approach may be helpful to reduce the occurrence of AMS and leads to better acclimatisation at high altitude in shorter duration. The present study evaluates the role of biochemical markers of acclimatisation after IHT before induction to actual high altitude. The study participants were Indian Army Personnel (n=30) and they were divided into two groups of control (n=16) and IHT exposed (n=14). The intermittent hypoxia training was administered at 12 per cent Oxygen for 4h/day for 4 days at sea level using normobaric hypoxia chamber and within 24 hrs - 48 hrs the subjects were airlifted to Leh, Ladakh, India at 11,700 ft. Preconditioning with IHT may be beneficial in maintaining antioxidant levels and ameliorate oxidative stress at high altitude. The hypoxia responsive proteins like Hemeoxygenase -1 (HO-1) and Vascular endothelial growth factor (VEGF) and the cytoprotective stress proteins, which facilitate the acclimatisation, may also get benefited by IHT exposure.

Can a predictive model for extubation readiness in preterm infants improve rates of successful extubation?

Extubation readiness is a complex, multifactorial topic with important clinical implications. In the premature neonatal population, there are no proven predictors of extubation readiness, success or failure; decisions surrounding extubation are left to clinician judgement resulting in practice variability and high rates of failure.1 Frequency of failed elective extubation in this patient population ranges from 23% to 42%.2-4 Extubation failure has been demonstrated to be associated with increased rates of death, bronchopulmonary dysplasia and retinopathy of prematurity as well as prolonged respiratory support requirement and hospitalisation.3, 4 In the current study, Gupta and colleagues created an extubation readiness estimator with available clinical and demographic data. The authors have made their calculator available to the public (http://elasticbeanstalk-us-east-2-676799334712.s3-website.us-east-2.amazonaws.com). After entering the gestational age, extubation day of life, pre-extubation per cent oxygen, highest RSS in first 6 hours, weight at extubation and pre-extubation pH, the clinician will receive the probability of successful extubation. Importantly, in this predictive model, the sensitivity and specificity of the prediction change with the results of the calculated probability of successful extubation. If the calculator predicts a 60% chance of success, the authors report 87% sensitivity and 53% specificity. This indicates that 87% of patients with similar values inserted into the calculator who succeed extubation will be predicted to succeed, and 53% of patients who fail extubation will be predicted to fail. If the calculator predicts an 80% chance of success, the sensitivity falls considerably to 54%; this implies that the ability to predict who will succeed is decreased at this level. Conversely, the sensitivity increases to 81%, suggesting that the ability to predict who will fail improves. Though difficult to conceptualise, this change in ‘test performance’ is intuitive and analogous to the way a clinician might make their own prediction. For example, a provider who feels an infant has a 95% chance of successful extubation likely has a high degree of certainty about the estimation. A clinical who feels an infant has only a 60% chance of extubation success may have uncertainty regarding the exact percentage. In this way, the predictive model performs similarly to clinical judgement, performing less well as uncertainty increases. A predictive model is most useful when it provides added certainty in the latter scenario; it is unlikely to be applied or improve outcomes if it only performs well when extubation success is either highly probable or very unlikely. It is unknown how the tool derived retrospectively will perform prospectively, and this uncertainty has potential to result in unanticipated harm. The authors comment that use of the estimator may help facilitate earlier extubation in infants estimated to have a high chance of success—if this hypothesis is true, rates of successful extubation should increase. Alternatively, a poor score could prevent an extubation attempt in some babies, with the unanticipated consequence of increasing ventilation days and lung injury. The balance of these potential harms and benefits should be prospectively assessed with broad implementation of this tool. None. URL TO THE FULL REVIEW ON THE EBNEO WEBSITE https://ebneo.org/2020/12/extubation-readiness/

Suspected venous air embolism during thoracic limb amputation in a dog

A six-year-old dog was anaesthetised for the amputation of her left forequarter. Preoperative haematology, biochemistry and physical examination were unremarkable. Twenty minutes into surgery, a sudden decrease in end tidal...

Comparison of endoscopic endotracheal intubation and the v-gel supraglottic airway device for spontaneously ventilating New Zealand white rabbits undergoing ovariohysterectomy

BackgroundDue to the technical difficulties with endotracheal intubation of rabbits, a prospective, randomised, controlled study was performed to compare a rabbit-specific supraglottic airway device (SGAD), the v-gel, with endoscopic endotracheal...

Carbon dioxide narcosis due to human error in a dog

Incorrect assembly of a parallel Lack (Mapleson A) breathing system resulted in carbon dioxide narcosis in a dog due to rebreathing of expiratory gases. A seven-year-old, male neutered Rottweiler, weighing 49 kg, failed to recover after discontinuation of inhalational anaesthesia following a forequarter amputation for osteosarcoma. During recovery, the endotracheal tube had been connected to a parallel Lack anaesthetic breathing system delivering 100 per cent oxygen at 5 l/minute. Although a prolonged recovery, 30 minutes, all vital parameters were considered within normal limits until a severe increase in respiratory effort was noted. Capnography revealed rebreathing with an end-tidal carbon dioxide tension of >150 mm Hg (>19.9 kPa). The dog was transferred to a circle breathing system, and with normalisation of the capnogram, recovery proceeded without further complications. Visual inspection of the parallel Lack breathing system revealed misassembly which had resulted in rebreathing of expiratory gases, extreme hypercapnia causing prolonged recovery due to narcosis.

Rhinitis following intraoperative gastro-oesophageal reflux in a dog

A four-month-old, male dog underwent surgical repair of femoral and pelvic fracture. The dog was premedicated with acepromazine combined with morphine; anaesthesia was induced with propofol to effect and maintained...

Enhanced strength and ductility in a high-entropy alloy via ordered oxygen complexes.

Oxygen, one of the most abundant elements on Earth, often forms an undesired interstitial impurity or ceramic phase (such as an oxide particle) in metallic materials. Even when it adds strength, oxygen doping renders metals brittle1-3. Here we show that oxygen can take the form of ordered oxygen complexes, a state in between oxide particles and frequently occurring random interstitials. Unlike traditional interstitial strengthening4,5, such ordered interstitial complexes lead to unprecedented enhancement in both strength and ductility in compositionally complex solid solutions, the so-called high-entropy alloys (HEAs)6-10. The tensile strength is enhanced (by 48.5 ± 1.8 per cent) and ductility is substantially improved (by 95.2 ± 8.1 per cent) when doping a model TiZrHfNb HEA with 2.0 atomic per cent oxygen, thus breaking the long-standing strength-ductility trade-off11. The oxygen complexes are ordered nanoscale regions within the HEA characterized by (O, Zr, Ti)-rich atomic complexes whose formation is promoted by the existence of chemical short-range ordering among some of the substitutional matrix elements in the HEAs. Carbon has been reported to improve strength and ductility simultaneously in face-centred cubic HEAs12, by lowering the stacking fault energy and increasing the lattice friction stress. By contrast, the ordered interstitial complexes described here change the dislocation shear mode from planar slip to wavy slip, and promote double cross-slip and thus dislocation multiplication through the formation of Frank-Read sources (a mechanism explaining the generation of multiple dislocations) during deformation. This ordered interstitial complex-mediated strain-hardening mechanism should be particularly useful in Ti-, Zr- and Hf-containing alloys, in which interstitial elements are highly undesirable owing to their embrittlement effects, and in alloys where tuning the stacking fault energy and exploiting athermal transformations13 do not lead to property enhancement. These results provide insight into the role of interstitial solid solutions and associated ordering strengthening mechanisms in metallic materials.

Impact of sleep characteristics and obesity on diabetes and hypertension across genders and menopausal status: the Nagahama study.

The individual prevalence of sleep-disordered breathing (SDB), short sleep duration, and obesity is high and increasing. The study aimed to investigate potential associations between SDB, objective sleep duration, obesity, diabetes and hypertension across genders, and the effect of pre- or post-menopausal status. A cross-sectional study evaluated 7051 community participants with wrist actigraphy for a week, and nocturnal oximetry ≥ 2 nights. SDB was assessed by 3 per cent oxygen desaturation index (ODI) corrected for sleep duration obtained from wrist actigraphy. Moderate-to-severe SDB was defined as ODI3% levels ≥ 15 per hour. Both logODI3% and body mass index showed independent negative associations with sleep duration (β = -0.16, p < 0.001 and β = -0.07, p < 0.001, respectively). Moderate-to-severe SDB (men/premenopausal women/postmenopausal women; 23.7/1.5/9.5%, respectively) was associated with a higher risk of diabetes in premenopausal women (OR 28.1; 95%CI 6.35-124.6; p < 0.001) and postmenopausal women (OR 3.25; 95%CI 1.94-5.46; p < 0.001), but not in men (OR 1.47; 95%CI 0.90-2.40; p = 0.119). Moderate-to-severe SDB was associated with a higher risk of hypertension in men (OR 3.11; 95%CI 2.23-4.33; p < 0.001), premenopausal women (OR 3.88; 95%CI 1.42-10.6; p = 0.008), and postmenopausal women (OR 1.96; 95%CI 1.46-2.63; p < 0.001). Short sleep duration was not associated with diabetes or hypertension. The associations of obesity with diabetes or hypertension were indirectly mediated by SDB (24.0% and 21.5%, respectively), with possible sex differences emerging (men/women; 15.3/27.8% and 27.0/16.9%, respectively). Notwithstanding the cross-sectional design, SDB and obesity, but not short sleep duration, were independently associated with diabetes and hypertension, with gender and menopausal status-related differences in risk emerging.

Postconditioning effects of argon or xenon on early graft function in a porcine model of kidney autotransplantation.

Ischaemia-reperfusion injury is inevitable during renal transplantation and can lead to delayed graft function and primary non-function. Preconditioning, reconditioning and postconditioning with argon and xenon protects against renal ischaemia-reperfusion injury in rodent models. The hypothesis that postconditioning with argon or xenon inhalation would improve graft function in a porcine renal autotransplant model was tested. Pigs (n = 6 per group) underwent left nephrectomy after 60 min of warm ischaemia (renal artery and vein clamping). The procured kidney was autotransplanted in a separate procedure after 18 h of cold storage, immediately after a right nephrectomy. Upon reperfusion, pigs were randomized to inhalation of control gas (70 per cent nitrogen and 30 per cent oxygen), argon (70 per cent and 30 per cent oxygen) or xenon (70 per cent and 30 per cent oxygen) for 2 h. The primary outcome parameter was peak plasma creatinine; secondary outcome parameters included further markers of graft function (creatinine course, urine output), graft injury (aspartate aminotransferase, heart-type fatty acid-binding protein, histology), apoptosis and autophagy (western blot, terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) staining), inflammatory mediators and markers of cell survival/growth (mRNA and tissue protein quantification), and animal survival. Results are presented as median (i.q.r.). ANOVA and Kruskal-Wallis tests were used where indicated. Peak plasma creatinine levels were similar between the groups: control 20·8 (16·4-23·1) mg/dl, argon 21·4 (17·1-24·9) mg/dl and xenon 19·4 (17·5-21·0) mg/dl (P = 0·607). Xenon was associated with an increase in autophagy and proapoptotic markers. Creatinine course, urine output, injury markers, histology, survival and inflammatory mediators were not affected by the intervention. Postconditioning with argon or xenon did not improve kidney graft function in this experimental model. Surgical relevance Ischaemia-reperfusion injury is inevitable during renal transplantation and can lead to delayed graft function and primary non-function. Based on mainly small animal experiments, noble gases (argon and xenon) have been proposed to minimize this ischaemia-reperfusion injury and improve outcomes after transplantation. The hypothesis that postconditioning with argon or xenon inhalation would improve graft function was tested in a porcine kidney autotransplantation model. The peak plasma creatinine concentration was similar in the control, argon and xenon groups. No other secondary outcome parameters, including animal survival, were affected by the intervention. Xenon was associated with an increase in autophagy and proapoptotic markers. Despite promising results in small animal models, postconditioning with argon or xenon in a translational model of kidney autotransplantation was not beneficial. Clinical trials would require better results.

A large oxygen-dominated core from the seismic cartography of a pulsating white dwarf.

White-dwarf stars are the end product of stellar evolution for most stars in the Universe. Their interiors bear the imprint of fundamental mechanisms that occur during stellar evolution. Moreover, they are important chronometers for dating galactic stellar populations, and their mergers with other white dwarfs now appear to be responsible for producing the type Ia supernovae that are used as standard cosmological candles. However, the internal structure of white-dwarf stars-in particular their oxygen content and the stratification of their cores-is still poorly known, because of remaining uncertainties in the physics involved in stellar modelling codes. Here we report a measurement of the radial chemical stratification (of oxygen, carbon and helium) in the hydrogen-deficient white-dwarf star KIC08626021 (J192904.6+444708), independently of stellar-evolution calculations. We use archival data coupled with asteroseismic sounding techniques to determine the internal constitution of this star. We find that the oxygen content and extent of its core exceed the predictions of existing models of stellar evolution. The central homogeneous core has a mass of 0.45 solar masses, and is composed of about 86 per cent oxygen by mass. These values are respectively 40 per cent and 15 per cent greater than those expected from typical white-dwarf models. These findings challenge present theories of stellar evolution and their constitutive physics, and open up an avenue for calibrating white-dwarf cosmochronology.

Suspected vagal reflex bradycardia in a calf undergoing surgical resection of an infected urachus

A four-week-old Charolais heifer was referred for surgical treatment of an infected umbilicus. The heifer was sedated with intravenous xylazine, and an indwelling intravenous jugular cannula was placed. General anaesthesia...

Successful short-term mechanical ventilation in a brachycephalic dog following aspiration pneumonia

Aspiration pneumonia is a relatively common concurrent disease in animals suffering from brachycephalic obstructive airway syndrome (BOAS). In addition to surgical correction of anatomical abnormalities, deterioration of respiratory function in...

Clinical effect of hyperbaric oxygen therapy in adhesive postoperative small bowel obstruction

Hyperbaric oxygen (HBO) therapy is a controversial treatment for adhesive postoperative small bowel obstruction, with only a few small studies reported. The aim of this study was to assess the clinical value of HBO therapy in the treatment of adhesive postoperative small bowel obstruction. Between April 2006 and March 2012, all patients with adhesive postoperative small bowel obstruction were treated using either decompression therapy or HBO. Patients undergoing HBO therapy were treated once a day at a pressure of 2·0 atmospheres absolute and received 100 per cent oxygen. Patients showing no clinical and radiological improvement with HBO therapy were converted to decompression therapy by means of a long tube. Medical records were reviewed and outcomes analysed. A total of 305 patients were treated, of whom 142 underwent tube decompression therapy during the first 3 years and the remaining 163 had HBO therapy during the last 3 years. The median number of HBO treatments was 3 (range 1-7). A total of 143 patients (87·7 per cent) were treated successfully with HBO without long-tube decompression. HBO therapy was associated with earlier resumption of oral intake (mean 4·7 versus 6·5 days; P = 0·001) and a shorter hospital stay (mean 10·3 versus 14·1 days; P = 0·001). The rate of operation was 7·4 per cent in the HBO group and 14·8 per cent in group treated by decompression alone (P = 0·037). In this study, HBO therapy was safe for the treatment of adhesive postoperative small bowel obstruction. It reduced the need for surgery and time to recovery as well as the hospital stay.

Cardiorespiratory, anaesthetic and recovery effects of morphine combined with medetomidine and alfaxalone in rabbits

Ten New Zealand White rabbits were used in a crossover experimental study: 200 µg/kg medetomidine and 1 (M1) or 2 mg/kg (M2) morphine were administered intramuscularly. After preoxygenation, anaesthesia was...

50 Years Ago in The Journal of Pediatrics: The Effect of Breathing 40 Per Cent Oxygen on the Arterial Blood Gas Tension of Babies With Bronchiolitis

50 Years Ago in The Journal of Pediatrics: The Effect of Breathing 40 Per Cent Oxygen on the Arterial Blood Gas Tension of Babies With Bronchiolitis

Oxygen: when less may be more

Veterinary RecordVolume 169, Issue 17 p. 437-438 Research Oxygen: when less may be more Federico Corletto PhD, CertVA, DipECVAA, MRCVS, Corresponding Author Federico Corletto PhD, CertVA, DipECVAA, MRCVS fc@dickwhitereferrals.com Dick...

Evaluation of decay resistance for steam-heat-treated wood

The objective of this research was to evaluate the influence of steam-heat treatment on the decay resistance of Chinese white poplar and Chinese fir wood against the wood-rotting fungi Gloeophyllum trabeum (Pers.:Fr.) Murrill. The Chinese white poplar and Chinese fir specimens were obtained from Shandong and Hunan provinces, respectively. They were steam-heat-treated at 170, 185, 200, 215, or 230 oC with time duration of 1, 2, 3, 4, and 5 hrs in an air-tight chamber that comprised less than 2 per cent oxygen. According to the standard GB/T 13942.1-92, the decay resistance experiments were completed with the wood-rotting fungi G. trabeum on an agar block test with 12-week incubation. The results of steam-heat treatment indicated that, compared to a weight loss of 56% for untreated samples, a weight loss of 45% decreased to just 2% for Chinese white poplar with an increase in temperature from 170 to 230℃. No weight loss was observed in the steam-heat-treated China-fir heartwood, sapwood, and untreated sapwood specimens, while only a weight loss of 4.739% in untreated China-fir heartwood specimens was found.

Increased dimensional stability of Chinese fir through steam-heat treatment

Chinese Fir is one of the most commonly planted tree species in China. As a fast-growing species, the main drawback is dimensional instability, which limits its applications. Steam-heat treatment is one of the effective methods to improve the dimensional stability of wood. Heartwood and sapwood of Chinese fir were treated using thermal modification with steam that was used as a heating medium and a shielding gas at temperatures ranging from 170 to 230°C and length of time from 1 to 5 hours in an airtight chamber with an atmosphere comprising less than 2 per cent of oxygen. The effect of steam-heat treatment on anti-shrink efficiency and anti-swelling efficiency were examined. The results indicated that the dimensional stability of the wood was increased by 73% for heartwood and 71% for sapwood at 230°C for 5 hours, respectively.