What can we Learn from Patients who Died from Covid-19 Following Escalation to a Respiratory High Dependency Unit for Trial of Non-Invasive Respiratory Support?

Background: Covid-19 infection is associated with significant risk of death, particularly in older, comorbid patients. Emerging evidence supports use of non-invasive respiratory support (CPAP and high-flow nasal oxygen [HFNO]) in this context, but little is known about its use in patients receiving end-of-life care. Methods: This was a retrospective study of 33 patients who died of Covid-19 on the Respiratory High Dependency Unit at the John Radcliffe Hospital, Oxford between 28/03/20 and 20/05/20. Data was sourced via retrospective review of electronic patient records and drug charts. Results: Patients dying from Covid-19 on the Respiratory HDU were comorbid with median Charlson Comorbidity Index 5 (IQR 4-6); median age 78 (IQR 72-85). Respiratory support was trialled in all but one case with CPAP being the most common form of first line respiratory support (84.8%) however, was only tolerated in 44.8% of patients. Median time to death was 10.7 days from symptom onset (IQR 7.5-14.6) and 4.9 days from hospital admission (IQR 3.1-8.3). 48.5% of patients remained on respiratory support at the time of death. Conclusions: End-of-life care for patients with Covid-19 remains a challenge. Patients tend to be frail and comorbid with a rapid disease trajectory. Non-Invasive Respiratory Support may play a key role in symptom management in select patients, however, further work is needed in order to identify patients who will most benefit from Respiratory Support and those for whom withdrawal may prevent unnecessary distress at the end of life or potential prolongation of suffering.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Influence of blanketing and season on vitamin D and parathyroid hormone, calcium, phosphorus, and magnesium concentrations in horses in New Zealand

The aims of the study were to determine the effect of season and blanketing on vitamin D synthesis in horses and examine the interaction between vitamin D and other analytes involved in calcium homeostasis. Twenty-one healthy horses at pasture were included; 5 were covered with standard horse blankets including neck rugs. Blood samples were collected for 13 mo and analyzed for 25-hydroxyvitamin D2 (25OHD2) and 25-hydroxyvitamin D3 (25OHD3), 1,25-dihydroxyvitamin D (1,25[OH]2D), ionized calcium (iCa), total calcium (tCa), phosphorus (P), total magnesium (tMg), and parathyroid hormone (PTH). Grass and hay samples were collected and analyzed for vitamin D, calcium, phosphorus, and magnesium. Climate data were also collected. The serum concentration of 25OHD3 in horses was either undetectable or below the detection limit of the assay, and the main form of 25OHD was 25OHD2. No differences in serum 25OHD2, 1,25(OH)2D, iCa, tCa, P, tMg, and PTH (P ≥ 0.05) concentrations were seen between the 2 groups. Associations were seen between iCa and PTH (P < 0.05), iCa and tMg (P < 0.05), and dietary vitamin D and 25OHD2 (P < 0.05). A strong seasonal trend was seen in serum 25OHD2 (P < 0.0001), which was higher during spring and summer when the amount of sunshine and UV radiation was higher. Parathyroid hormone and 1,25(OH)2D showed opposing trends with PTH higher in winter whereas 1,25(OH)2D was higher in summer. The results suggest that dietary vitamin D may be necessary for horses to fulfill their vitamin D requirements; however, further research is required to determine the contribution of vitamin D3 synthesis in the skin to the vitamin D status of the horse.

Circadian rhythm of calciotropic hormones, serum calcium, phosphorus and magnesium during the shortest and longest days of the year in horses in New Zealand

A study was conducted to determine the circadian rhythms and trends of vitamin D metabolites including 25-hydroxyvitamin D₃ , 25-hydroxyvitamin D₂ , 1,25-dihydroxyvitamin D and parathyroid hormone, in addition to serum calcium, phosphorus and magnesium concentrations in horses over 48 h on the shortest and longest days of the year in 2013. Five healthy adult horses (Equus caballus) were on a constant pasture feeding regimen, and blood samples were collected from each horse every 3 h over a 48-h period, starting at 07:00 PM on day one and finishing at 07:00 PM on day three, for the measurement of calciotropic hormones and electrolytes. There was a significant difference between the serum concentration of calciotropic hormones, iCa, tCa, P and tMg between the shortest (winter) and longest (summer) days of the year in horses. Serum concentration of 25OHD₃ was very low and mostly undetectable. Serum iCa, 1,25(OH)₂ D and PTH concentrations clearly showed a circadian rhythm on the longest days of the year and serum tCa, P and tMg concentrations showed a diurnal pattern on the longest days (summer) of the year. None of the analytes showed any circadian rhythm on the shortest days (winter) of the year. The result of this study could have significant relevance to equine athletes travelling to international equestrian competitions and facing a huge time and seasonal differences that might affect their ability to adjust their circadian rhythms to new time zones.

Comparative study on the efficacy of pioglitazone in Caucasian and Maori-Polynesian patients with poorly controlled type 2 diabetes

AIM

Although the pharmodynamic properties of the thiazolidinedione (TZD) insulin-sensitizing agents in the treatment of type 2 diabetes are well established, there are no studies comparing the pharmacoefficacy of these drugs in different ethnic groups. The aim of this pilot, prospective study was to examine the hypothesis that the efficacy of TZDs may vary depending on ethnicity. This aim was achieved by comparing the effects of 6-months treatment with pioglitazone (45 mg/day) on glucose control and metabolic and cardiovascular risk factors in Caucasian and Maori-Polynesian patients with poorly controlled type 2 diabetes.

METHODS

Ninety-seven patients (40 Caucasian and 57 Maori-Polynesian) with type 2 diabetes were selected for the study from our clinical databases if they were on the maximum tolerated dose of oral agents and had a haemoglobin A(1c) (HbA(1c)) > 8.0% for at least 2 months. All the patients received pioglitazone (45 mg/day) for 6 months in addition to their regular diabetes therapy. Clinical data and blood samples were collected at monthly intervals and the following indices measured: weight, blood pressure, oedema score, HbA(1c), plasma glucose, alanine amino transferase and adiponectin levels and plasma lipid profile, including low-density lipoprotein (LDL)-cholesterol particle size and atherogenic index of plasma (AIP). The data of the 81 patients who finished the study were analysed using analysis of variance, chi-square analysis and multiple regression methods.

RESULTS

The absolute change from baseline in mean HbA(1c) (Caucasian -1.4% vs. Maori-Polynesian -1.3%) and fasting glucose levels (Caucasian -2.1 mmol/l vs. Maori-Polynesian -2.8 mmol/l) was similar in the two groups. Pioglitazone caused an improvement in lipid profile in both ethnic groups, with a reduction in mean values of atherogenic fractions (triglyceride: Caucasian -0.5 mmol/l, p < 0.001 vs. Maori-Polynesian -0.3 mmol/l, p = 0.05; very low-density lipoprotein (VLDL)-cholesterol: Caucasian -0.11 mmol/l, p = 0.001 vs. Maori-Polynesian -0.04 mmol/l, p = 0.85; VLDL-triglyceride: Caucasian -0.36 mmol/l, p < 0.001 vs. Maori-Polynesian -0.22 mmol/l, p = 0.14; apolipoprotein B: Caucasian -0.09 mmol/l, p = 0.03 vs. Maori-Polynesian -0.08 mmol/l, p = 0.18). These changes were associated with an increase in LDL-cholesterol particle size (Caucasian +0.23 nm, p = 0.05 vs. Maori-Polynesian +0.26 nm, p = 0.04) and a decrease in AIP (Caucasian -0.14, p < 0.001 vs. Maori-Polynesian -0.08, p = 0.04). While the changes in the lipid indices tended to be greater in the Caucasian group, the difference in lipid response between the two ethnic groups was not statistically significant. Multiple regression analyses showed that the baseline value of the individual lipid fractions was the main determinant of the changes in lipid levels.

CONCLUSIONS

These results demonstrated that pioglitazone has similar beneficial effects on glucose control and plasma lipid profile in Caucasian and Maori-Polynesian patients with poorly controlled type 2 diabetes. Our data showed that while the improvement in lipid profile was more pronounced in Caucasian patients than in Maori-Polynesian patients, this difference was not statistically significant.

Therapy-related myelodysplasia and leukemia occur infrequently following VP-16 priming and autotransplantation without total body irradiation

The use of VP-16 for stem cell mobilization has been cited as a significant risk factor for the development of therapy-related myelodysplasia/leukemia (tMDS/tAML) following autologous transplantation. The present study analyzed a large cohort of patients who underwent autotransplantation following stem cell mobilization with VP-16 and radiation-free preparation in order to determine the risk of tMDS/tAML. The estimated incidence of 9.9% at 7 years suggests that in the absence of TBI, VP-16 priming is not associated with an increased incidence of tMDS/tAML.

The relation of ethnic identification with cigarette smoking among US urban African American and Latino youth: a pilot study

Primarily African American and Latino seventh graders (N = 545) attending health and science classes at three urban Southern California junior high schools were administered a 13-item ethnic identification assessment during one class period, to investigate the relationship between ethnic identification and tobacco use. For African Americans, the perception of looking different from other ethnic groups was found to be associated with avoidance of peer tobacco use. Among Latinos, the perception of being liked by other ethnic groups, and enjoying interaction with people outside of their ethnic group, were found to be associated with negating peer influence for tobacco use. Watching television shows with main characters of same ethnic group was associated with being able to make friends without using tobacco, for both ethnic groups. For Latinos, ever trying a cigarette was associated with the perception of being liked by other ethnic groups. These results suggest there may be elements inherent in ethnic identification protective against peer influence for smoking among ethnic minority youth. Also, acculturation of Latinos to the majority population may increase their risk for experimentation with tobacco products.

Qualitative development of smoking prevention programming for minority youth

Brief discussion groups were completed with 211 predominantly African American and Latino seventh graders to investigate reasons for adolescent smoking and perceived efficacious smoking prevention program strategies. Study data consisted of audiotaped group discussions, which were content-coded, and open-ended posttest responses. The results indicated that, through use of relatively nondirected methods, reasons for smoking and smoking prevention methods generated by African American and Latino youth were similar to those popularly endorsed by white youths in previous research. Perhaps, optimal program contents are similar across ethnic groups. Still, one may speculate that identification with and diffusion of prevention messages may be maximized if they demonstrate cultural relevancy.

Empirical development of brief smoking prevention videotapes which target African-American adolescents

Two studies are described which provide evaluations for two brief videotapes developed as supplemental materials in the prevention of tobacco use among African-American adolescents. One videotape (the "soap opera") provides a more general audience-oriented presentation of prevention material and it was filmed primarily at a shopping mall, whereas the other videotape (the "rap") provides a "hip-hop generation" presentation, and it was filmed primarily at an outdoor hangout. The first study compared the two videotapes against each other. The second study compared the two videotapes combined in the same presentation, controlling for order of presentation, against a discussion group control. The results of the two studies indicated few differences in receptivity to the two videotapes among primarily African-American and Latino young adolescents. The rap videotape was rated as more accurate in its depiction of the African-American lifestyle, although both videotapes were equally liked. When shown together, the videotapes were not found to be superior in decreasing behavioral intention to smoke compared to a discussion group control. No change in trial of smoking was observed within or across conditions measured over a pre-post summer interval. These data suggest that "culturally sensitive" videotapes have no more of a short-term effect on youth than do other types of brief interventions which involve minority implementers.

Blood flow measurement by Doppler ultrasound: a question of angles

Ultrasound Doppler equipment is widely used to estimate blood velocity and volume flow. Recently there has been correspondence concerning the origin of the Doppler shift in blood vessels. The assumption that only the movement of the target need be considered is challenged by the observation that Doppler shifts occur where there is relative motion. In blood there is unlikely to be relative motion between a reflecting blood corpuscle and its supporting plasma. In the simple case of plug flow the relative movement takes place at the vessel wall. An investigation is described which uses a flow rig Doppler phantom to assess what effect, if any, this phenomenon would have on Doppler shift results obtained by insonating a vessel such as the aortic arch and range gating through a curved section where flow velocity gradients are encountered. It has been assumed that if the sample volume were to lie in that part of the vessel in which the blood velocity vector were directly towards the probe, then an angle of 0 degrees could be assumed for calculations using the Doppler equation. Our results indicate that the observed Doppler shifts lie midway between those expected if the shift were to occur solely at the first moving fluid boundary and those originating only from scatterers within the sample volume.

Kinetic characterization of reductant dependent processes of iron mobilization from endocytic vesicles

The reductant dependence of iron mobilization from isolated rabbit reticulocyte endosomes containing diferric transferrin is reported. The kinetic effects of acidification by a H(+)-ATPase are eliminated by incubating the endosomes at pH 6.0 in the presence of 15 microM FCCP to acidify the intravesicular milieu and to dissociate 59Fe(III) from transferrin. In the absence of reductants, iron is not released from the vesicles, and iron leakage is negligible. The second-order dependence of rate constants and amounts of 59Fe mobilized from endosomes using ascorbate, ferrocyanide, or NADH are consistent with reversible mechanisms. The estimated apparent first-order rate constant for mobilization by ascorbate is (2.7 +/- 0.4) x 10(-3) s-1 in contrast to (3.2 +/- 0.1) x 10(-4) s-1 for NADH and (3.5 +/- 0.6) x 10(-4) s-1 for ferrocyanide. These results support models where multiple reactions are involved in complex processes leading to iron transfer and membrane translocation. A type II NADH dehydrogenase (diaphorase) is present on the endosome outer membrane. The kinetics of extravesicular ferricyanide reduction indicate a bimolecular-bimolecular steady-state mechanism with substrate inhibition. Ferricyanide inhibition of 59Fe mobilization is not detected. Significant differences between mobilization and ferricyanide reduction kinetics indicate that the diaphorase is not involved in 59Fe(III) reduction. Sequential additions of NADH followed by ascorbate or vice versa indicate a minimum of two sites of 59Fe(III) residence; one site available to reducing equivalents from ascorbate and a different site available to NADH. Sequential additions using ferrocyanide and the other reductants suggest interactions among sites available for reduction. Inhibition of ascorbate-mediated mobilization by DCCD and enhancement of ferrocyanide and NADH-mediated mobilization suggest a role for a moiety with characteristics of a proton pore similar to that of the H(+)-ATPase. These data provide significant constraints on models of iron reduction, translocation, and mobilization by endocytic vesicles.

Non-operative management of malignant intestinal obstruction

Intestinal obstruction is a relatively common clinical problem in patients with advanced cancer, particularly those with colorectal and ovarian tumours. A proportion of patients have a non-malignant cause for their obstruction, but in the remaining patients obstruction will be caused by advanced malignancy itself. In the past, most patients were either managed surgically or by nasogastric intestinal decompression and intravenous hydration. Surgery in patients with advanced cancer is associated with high mortality and morbidity. Effective surgical decompression is difficult. We have managed 24 patients with advanced abdominal malignancy and previous operative or radiological evidence of intestinal obstruction without operation. The technique is only appropriate for patients in whom a solitary or correctable obstructing lesion can be excluded. The patient is encouraged to take free fluid and a diet low in fibre. Intestinal colic is managed with morphine, the dose required being titrated for each individual patient against background pain and colic. Vomiting is controlled by the parenteral administration of antiemetic drugs. To simplify drug administration, morphine and metoclopramide are mixed in the same syringe and infused subcutaneously simultaneously. In our 24 patients the mean survival rate after the onset of complete obstruction was 29.2 days. The mean dose of morphine infused was 9.2 mg/h, and the mean dose of metoclopramide was 6.9 mg/h. The case of an 82-year-old male patient is presented. We commend the technique to surgeons contemplating surgery in these very difficult patients. It is simple, relatively non-invasive and saves the patients the pain, discomfort and complications of unproductive surgery.