Dehydration and renal failure in older persons during heatwaves-predictable, hard to identify but preventable?

Characteristics and preventability of medication-related admissions for acute kidney injury and dehydration in elderly patients

PURPOSE

Patients with impaired renal function using medication that affects glomerular filtration rate are at increased risk of developing acute kidney injury (AKI) leading to hospital admissions. The risk increases during periods of dehydration due to diarrhoea, vomiting or fever (so-called "sick days"), or high environmental temperatures (heat wave). This study aims to gain insight into the characteristics and preventability of medication-related admissions for AKI and dehydration in elderly patients.

METHODS

Retrospective case series study in patients aged ≥ 65 years with admission for acute kidney injury, dehydration or electrolyte imbalance related to dehydration that was defined as medication-related. General practitioner's (GP) patient records including medication history and hospital discharge letters were available. For each admission, patient and admission characteristics were collected to review the patient journey. A case-by-case assessment of preventability of hospital admissions was performed.

RESULTS

In total, 75 admissions were included. Most prevalent comorbidities were hypertension, diabetes, and known impaired renal function. Diuretics and RAS-inhibitors were the most prevalent medication combination. Eighty percent of patients experienced non-acute onset of symptoms and 60% had contacted their GP within 2 weeks prior to admission. Around 40% (n = 29) of admissions were considered potentially preventable if pharmacotherapy had been timely and adequately adjusted.

CONCLUSION

A substantial proportion of patients admitted with AKI or dehydration experience non-acute onset of symptoms and had contacted their GP within 2 weeks prior to admission. Timely adjusting of medication in these patients could have potentially prevented a considerable number of admissions.

Speckle Noise Algorithm-Based Ultrasound Imaging in Evaluating the Therapeutic Effect of Blood Purification on Children with Kidney Failure and Analysis of Its Correlation with Serum Inflammatory Factor Levels

The study focused on the therapeutic effect of clinical treatment on urinary calculi with kidney failure and its relationship with the serum inflammatory factor levels. 90 children with melamine urinary calculi were selected as research subjects. Of them, 52 cases were in group 1 (nonrenal failure), and 38 cases were in group 2 (combined with renal failure). In addition, 35 hospitalized children with no history of melamine-contaminated milk feeding during the same period were used as healthy controls. They all underwent ultrasound imaging examination based on the speckle noise algorithm, and the prognosis was analyzed. It was found that the peak signal-to-noise ratio (PSNR), structural similarity (SSIM), and local edge preservation index (EPI) of the algorithm in this study were significantly greater than other algorithms (P < 0.05). The admission age of the children in group 1 was significantly younger than that of group 2, the bilateral stone rate was significantly higher than that in group 2, and the difference was statistically significant (P < 0.05). Of the 52 children in group 1, the stone disappeared in 25 cases after treatment, the stone was reduced in 20 cases, and the stone remained unchanged in 7 cases. The total effective rate of treatment was 88.46%. Of the 38 cases in group 2, the stone disappeared in 22 cases after treatment, the stone was reduced in 12 cases, and the stone remained unchanged in 4 cases. The total effective rate of treatment was 89.47%. No difference was noted in blood urea nitrogen (BUN), blood creatinine (Cr), TNF-α, and C-reactive protein (CRP) levels in group 1, group 2, and the healthy control group (P > 0.05). Hence, the denoising algorithm in this study has better denoising effects on ultrasound images than traditional algorithms, with higher definition and less noise and artifacts. The clinical treatment of children with urinary calculi and renal failure is highly effective, the renal function and serum inflammatory factor levels return to the normal range, and the inflammatory response is weakened.

A novel mouse model of heatstroke accounting for ambient temperature and relative humidity

Background

Heatstroke is associated with exposure to high ambient temperature (AT) and relative humidity (RH), and an increased risk of organ damage or death. Previously proposed animal models of heatstroke disregard the impact of RH. Therefore, we aimed to establish and validate an animal model of heatstroke considering RH. To validate our model, we also examined the effect of hydration and investigated gene expression of cotransporter proteins in the intestinal membranes after heat exposure.

Methods

Mildly dehydrated adult male C57/BL6J mice were subjected to three AT conditions (37 °C, 41 °C, or 43 °C) at RH > 99% and monitored with WetBulb globe temperature (WBGT) for 1 h. The survival rate, body weight, core body temperature, blood parameters, and histologically confirmed tissue damage were evaluated to establish a mouse heatstroke model. Then, the mice received no treatment, water, or oral rehydration solution (ORS) before and after heat exposure; subsequent organ damage was compared using our model. Thereafter, we investigated cotransporter protein gene expressions in the intestinal membranes of mice that received no treatment, water, or ORS.

Results

The survival rates of mice exposed to ATs of 37 °C, 41 °C, and 43 °C were 100%, 83.3%, and 0%, respectively. From this result, we excluded AT43. Mice in the AT 41 °C group appeared to be more dehydrated than those in the AT 37 °C group. WBGT in the AT 41 °C group was > 44 °C; core body temperature in this group reached 41.3 ± 0.08 °C during heat exposure and decreased to 34.0 ± 0.18 °C, returning to baseline after 8 h which showed a biphasic thermal dysregulation response. The AT 41 °C group presented with greater hepatic, renal, and musculoskeletal damage than did the other groups. The impact of ORS on recovery was greater than that of water or no treatment. The administration of ORS with heat exposure increased cotransporter gene expression in the intestines and reduced heatstroke-related damage.

Conclusions

We developed a novel mouse heatstroke model that considered AT and RH. We found that ORS administration improved inadequate circulation and reduced tissue injury by increasing cotransporter gene expression in the intestines.

Relationship between the Number of Deaths Due to Renal Failure and Air Temperature Parameters in Hokkaido and Okinawa Prefectures, Japan

Background: The aim of the present study was to investigate the relationship between the number of deaths due to renal failure and air temperature parameters in Hokkaido (the northernmost region) and Okinawa (the southernmost region) prefectures, Japan. Methods: Monthly data on the number of deaths due to renal failure between January 2008 and December 2016 and annual population data were collected from the Hokkaido and Okinawa official prefecture websites. Air temperature parameters were obtained from the Japan Meteorological Agency. The relationship between the number of deaths due to renal failure and air temperature parameters was evaluated by an ecological study. Results: The number of deaths due to renal failure (per 100,000 people/month) in Hokkaido and Okinawa were 2.28 ± 0.30 and 1.17 ± 0.31. In Hokkaido, the number of deaths due to renal failure negatively correlated with air temperature parameters in both sexes. The number of deaths due to renal failure was significantly higher in January than from June to September in all subjects. However, in Okinawa, no significant difference was observed among months. Conclusions: The present results suggest that the relationship between the number of deaths due to renal failure and air temperature parameters differs between Hokkaido and Okinawa.

Kidney physiology and pathophysiology during heat stress and the modification by exercise, dehydration, heat acclimation and aging

The kidneys' integrative responses to heat stress aid thermoregulation, cardiovascular control, and water and electrolyte regulation. Recent evidence suggests the kidneys are at increased risk of pathological events during heat stress, namely acute kidney injury (AKI), and that this risk is compounded by dehydration and exercise. This heat stress related AKI is believed to contribute to the epidemic of chronic kidney disease (CKD) occurring in occupational settings. It is estimated that AKI and CKD affect upwards of 45 million individuals in the global workforce. Water and electrolyte disturbances and AKI, both of which are representative of kidney-related pathology, are the two leading causes of hospitalizations during heat waves in older adults. Structural and physiological alterations in aging kidneys likely contribute to this increased risk. With this background, this comprehensive narrative review will provide the first aggregation of research into the integrative physiological response of the kidneys to heat stress. While the focus of this review is on the human kidneys, we will utilize both human and animal data to describe these responses to passive and exercise heat stress, and how they are altered with heat acclimation. Additionally, we will discuss recent studies that indicate an increased risk of AKI due to exercise in the heat. Lastly, we will introduce the emerging public health crisis of older adults during extreme heat events and how the aging kidneys may be more susceptible to injury during heat stress.

Preventative strategies and interventions to improve outcomes during heatwaves

Extreme weather events including recently experienced prolonged heatwaves are predicted to increase in frequency and intensity as a result of climate change. Vulnerable groups, and particularly older persons, are at increased risk of heat-related illness and mortality. Multimodal interventions that incorporate community, primary and secondary care programmes are required. Social programmes such as early warning systems, regional heat plans and community-led initiatives that specifically target the isolated, dependent older person are protective. Establishing clear and effective communication on health promotion and preventative measures is the key. Energy-efficient building design and eco-city planning are vital to reduce the impact of heatwaves at both a population and individual level. Anticipatory strategies should be adopted to ensure ample access to fluids, target barriers to increase oral intake and allow early identification of intercurrent illness, along with regular medication reviews. Prompt management of risk factors for the development of heat-related illness and treatment of complications such as heat stroke and cardiovascular events are keys to reducing the negative health impact of extreme heat in at-risk populations. Morbidity and mortality in heatwaves should be preventable. Evidence-based interventions are available to mitigate and prevent the negative health impact of extreme heat and should be implemented in all residential settings.