Thirst response to acute hypovolaemia in healthy women and women prone to vasovagal syncope

Underrecognition and undertreatment of thirst among hospitalized patients with restricted oral feeding and drinking

Thirst is distressing but overlooked by healthcare professionals. Patients experience thirst due to comorbidities, physical or cognitive limitations, and iatrogenesis. Nasogastric tube (NGT) use and nil-by-mouth(NBM) orders are common practices that can lead to thirst. However, thirst in these populations has never been formally studied. We aim to examine prevalence of recognition and treatment of thirst among NGT + NBM and NBM patients. Our descriptive study was conducted intermittently over 25 weeks, across 1.5 years, in 12 adult general medicine wards of a tertiary hospital. Cognitively intact NGT + NBM or NBM inpatients, defined as Abbreviated Mental Test score ≥ 8, were studied. One-time questionnaire was administered. Variables included: demography, co-morbidities, clinical condition, feeding route, thirst defined by thirst distress and/or intensity ≥ 3, pain, hunger and volume status. 88 NGT + NBM and NBM patients were studied. 69.3% suffered from thirst. Thirsty patients experienced significant thirst-related distress (mean score ± SD: 5.7 ± 2.5). Subjects with previous stroke and who were euvolemic tended towards thirst. 13.6% were asked about thirst by doctors or nurses. Thirst was a major source of patient distress in our study. We suggest that thirst needs to be actively identified and targeted to achieve person-centred care.

Signs of Dehydration after Hip Fracture Surgery: An Observational Descriptive Study

Background and Objectives: Dehydration might be an issue after hip fracture surgery, but the optimal tools to identify the dehydrated condition have not been determined. The aim of the present study was to compare the characteristics of elderly postoperative patients who were classified as dehydrated according to the methods used in the clinic. Materials and Methods: Thirty-eight patients aged between 65 and 97 (mean, 82) years were studied after being admitted to a geriatric department for rehabilitation after hip fracture surgery. Each patient underwent blood analyses, urine sampling, and clinical examinations. Results: Patients ingested a mean of 1,008 mL (standard deviation, 309 mL) of fluid during their first day at the clinic. Serum osmolality increased significantly with the plasma concentrations of sodium, creatinine, and urea. Seven patients had high serum osmolality (≥300 mosmol/kg) that correlated with the presence of tongue furrows (p < 0.04), poor skin turgor (p < 0.03), and pronounced albuminuria (p < 0.03). Eight patients had concentrated urine (urine-specific gravity ≥ 1.025) that correlated with a low intake of liquid and with a decrease in body weight during the past month of −3.0 kg (25–75 th percentiles, −5.1 to −0.9) versus +0.2 (−1.9 to +2.7) kg (p < 0.04). Conclusions: Renal fluid conservation of water, either in the form of hyperosmolality or concentrated urine, was found in 40% of the patients after hip fracture surgery. Hyperosmolality might not indicate a more severe fluid deficit than is indicated by concentrated urine but suggests an impaired ability to concentrate the urine.

Signs of Dehydration in Nursing Home Residents

OBJECTIVES

Although dehydration can affect mental and physical health, there is no clear, consistent, and reproducible diagnostic tool for this condition in older people. We applied multiple methods to detect dehydration with the aim of assessing the value of using urine analysis for this purpose.

DESIGN

Nonrandomized cohort study.

SETTING AND PARTICIPANTS

Sixty nursing home residents, aged 64-103 (mean 84) years.

METHODS

Sampling of morning urine, blood analyses, and clinical examination. A previously validated algorithm summarized the urine specific gravity, osmolality, creatinine, and color to a Fluid Retention Index (FRI).

RESULTS

The cut-off for renal fluid conservation consistent with dehydration (FRI ≥ 4.0) was reached by 51% of the cohort. No statistically significant linear correlation was found between FRI and serum osmolality (mean 307.5 mOsmol/kg) or plasma sodium (mean 139 mmol/L), but the subjects reported less thirst with increasing FRI scores (linear correlation r = -0.35; P < .03). Clinical examinations of mucous membranes and tongue furrows did not correlate with other markers of dehydration. Subjects with sunken eyes had higher C-reactive protein (P < .02) and lower albumin (P < .002) concentrations in plasma than the others, while impaired skin turgor only correlated with age (P < .04).

CONCLUSIONS/IMPLICATIONS

Renal fluid conservation consistent with dehydration was found in half of the nursing home residents, which could partially be accounted for by decreased thirst. Clinical examinations probably reflected the physical status and age more than dehydration. The lack of correlation between the serum osmolality and the FRI, both of which are purported to be gold standards for dehydration, raises questions about whether a gold standard exists.

Renal water conservation determines the increase in body weight after surgery: A randomized, controlled trial

Background:

The present study was undertaken to identify factors that correlate with the gain in body weight after surgery.

Methods:

Twenty-one patients (median age of 49 years) were randomized to receive either Ringer × s acetate or 6% dextran 70 as their first infusion fluid during cholecystectomy or hysterectomy. Each patient's body weight was measured before the surgery and on the first postoperative morning. Blood and urine samples were analyzed for signs of stress, inflammation, and kidney injury. The fluid retention index (FRI), which reflects how strongly the kidneys excrete or retain fluid, was also calculated.

Results:

The body weight increased by a median of 0.4 kg in the crystalloid fluid group and by 1.0 kg in the colloid fluid group (maximum 2.5 kg, P < 0.01). This difference was due to less urinary excretion after surgery in the colloid group (P < 0.03). The increase in body weight did not correlate with the infused fluid volume, the plasma concentrations of C-reactive protein or cortisol, or the urinary excretion of albumin, cortisol, or neutrophil gelatinase-associated lipocalin. However, the body weight increased with the postoperative FRI score (r = 0.64; P < 0.003) and with the surgery-induced change in FRI score (r = 0.72; P < 0.002).

Conclusion:

How strongly the kidneys excrete or retain fluid, which can be assessed by urine sampling, was the strongest indicator of the increase in body weight during the day of surgery. The amount of fluid alone did not correlate with the gain in body weight.

Slower Lower Limb Blood Pooling Increases Orthostatic Tolerance in Women with Vasovagal Syncope

Background and Aim: Slower lower limb blood pooling and associated blunted sympathetic activation has been detected in healthy women prone to orthostatic syncope. Whether these findings are true also for patients with vasovagal syncope (VVS) is unknown. The aim was to investigate initial blood pooling time (pooling_time, time to 50% of total blood pooling) together with hemodynamic responses and orthostatic tolerance during lower body negative pressure (LBNP) in VVS and healthy controls.

Methods and Results: Fourteen VVS women (25.7 ± 1.3 years) and 15 healthy women (22.8 ± 0.8 years) were subjected to single-step and graded LBNP to pre-syncope. Lower limb blood pooling (ml · 100 ml⁻¹), pooling_time (s), hemodynamic responses and LBNP-tolerance were evaluated. LBNP induced comparable lower limb blood pooling in both groups (controls, 3.1 ± 0.3; VVS, 2.9 ± 0.3 ml · 100 ml⁻¹, P = 0.70). In controls, shorter pooling_time correlated to higher LBNP-tolerance (r = –0.550, P < 0.05) as well as better maintained stroke volume (r = –0.698, P < 0.01) and cardiac output (r = –0.563, P < 0.05). In contrast, shorter pooling_time correlated to lower LBNP-tolerance in VVS (r = 0.821, P < 0.001) and larger decline in stroke volume (r = 0.611, P < 0.05). Furthermore, in controls, shorter pooling_time correlated to baroreflex-mediated hemodynamic changes during LBNP, e.g., increased vasoconstriction (P < 0.001). In VVS, pooling_time was not correlated with LBNP-induced baroreceptor unloading, but rather highly correlated to resting calf blood flow (P < 0.001).

Conclusions: Shorter pooling_time seems to elicit greater sympathetic activation with a concomitant higher orthostatic tolerance in healthy women. The contrasting findings in VVS indicate a deteriorated vascular sympathetic control suggesting well-defined differences already in the initial responses during orthostatic stress.

Thirst trajectory and factors associated with persistent thirst in patients with heart failure

BACKGROUND

Thirst is often increased in patients with heart failure (HF) and can cause distress during the course of the condition. The aim of the present study was to describe the trajectory of thirst during an 18-month period and to identify variables associated with persistent thirst in patients with HF.

METHODS AND RESULTS

Data were collected from 649 patients with HF with the use of the Revised Heart Failure Compliance Scale at 1, 6, 12, and 18 months after a period of hospital treatment for worsening HF. Thirst trajectory was described for the 4 follow-up visits and logistic regression analysis was used to identify factors independently associated with persistent thirst. In total, 33% (n = 212) of the patients reported thirst on ≥1 occasions and 34% (n = 46) continued to have thirst at every follow-up visit. Nineteen percent (n = 121) of the patients had persistent thirst. Patients with persistent thirst were more often younger and male and had more HF symptoms. Higher body mass index and serum urea also increased the risk of persistent thirst.

CONCLUSIONS

Patients with HF who were thirsty at the 1-month follow-up were more often also thirsty at subsequent visits. Assessment of thirst is warranted in clinical practice because one-fifth of patients suffer from persistent thirst.