The effect of vasopressin on solute and water excretion during and after surgical operations

Duloxetine-induced Syndrome of Inappropriate Secretion of Antidiuretic Hormone in a Super-elderly Patient

Duloxetine is widely used for pain control and depressive syndromes. One of its potential side effects is syndrome of inappropriate secretion of antidiuretic hormone (SIADH). Duloxetine-induced SIADH causes hyponatremia, which leads to a variety of symptoms and has previously been reported in the elderly. In the present case, we experienced a case of the rapid onset of SIADH in a super-elderly woman receiving low-dose duloxetine. Elderly patients tend to have lower duloxetine doses and an earlier onset than non-elderly patients. When hyponatremia occurs after duloxetine administration, duloxetine-induced SIADH should be considered, especially in high-risk elderly patients, regardless of the duloxetine dose or duration of treatment.

Serum Sodium, Patient Symptoms, and Clinical Outcomes in Hospitalized Patients with COVID-19

Introduction:

Disorders of serum sodium (SNa) are common in hospitalized patients with COVID-19 and may reflect underlying disease severity. However, the association of SNa with patient-reported outcomes is not clear.

Methods:

The Brigham and Women’s Hospital COVID-19 Registry is a prospective cohort study of consecutively admitted adult patients with confirmed SARS-CoV-2 infection (n = 809). We examined the associations of SNa (continuous and tertiles) on admission with: (1) patient symptoms obtained from detailed chart review; and (2) in-hospital mortality, length of stay, and intensive care unit (ICU) admission using unadjusted and adjusted logistic regression models. Covariates included demographic data and comorbidities.

Results:

Mean age was 60 years, 48% were male, and 35% had diabetes. The most frequent symptoms were cough (64%), fever (60%), and shortness of breath (56%). In adjusted models, higher SNa (per mmol/L) was associated with lower odds of GI symptoms (OR 0.96; 95% CI 0.92-0.99), higher odds of confusion (OR 1.08; 95% CI 1.04-1.13), in-hospital mortality (OR 1.06; 95% CI 1.02-1.11), and ICU admission (OR 1.09; 95% CI 1.05-1.13). The highest sodium tertile (compared with the middle tertile) showed similar associations, in addition to lower odds of either anosmia or ageusia (OR 0.30; 95% CI 0.12-0.74).

Conclusion:

In this prospective cohort study of hospitalized patients with COVID-19, hypernatremia was associated with higher odds of confusion and in-hospital mortality. These findings may aid providers in identifying high-risk patients who warrant closer attention, thereby furthering patient-centered approaches to care.

A case of Inappropriate Antidiuretic Hormone Secretion Syndrome Associated with COVID-19 Pneumonia

At the end of 2019, a novel coronavirus was identified as the cause of a cluster of pneumonia in China and it spread quickly to other countries. Although Covid-19 causes severe pneumonia, it is known that it can be associated with different diseases and prognosis of disease can be due to many of disorders such as hyponatremia. A 65-year-old female patient with sarcoidosis, cronic obstructive lung disease, hypertension and congestive heart failure presented to the emergency department with shortness of breath and fever. Oropharyngeal swab for Covid-19 PCR test was positive. After the initiation of treatment, the patient developed hyponatremia. This case is remarkable because there is no reported case of Covid-19 and inappropriate ADH syndrome coexistence and it demonstrates that there may be a correlation between Covid-19 infection prognosis and hyponatremia.

Employment of vasopressin receptor antagonists in management of hyponatraemia and volume overload in some clinical conditions

WHAT IS KNOWN AND OBJECTIVE

Hyponatraemia, the most common electrolyte imbalance occurring in hospitalized subjects, is usually classified as hypovolaemic, euvolaemic or hypervolaemic. Hyponatraemia is a predictor of death among subjects with chronic heart failure and cirrhosis. The inappropriate secretion of the antidiuretic hormone (AVP) seems to be of pivotal importance in the decline of serum sodium concentration in these clinical conditions. The objective of this review was to summarize recent progress in management of hyponatraemia in SIADH, cirrhosis and heart failure.

METHODS

Literature searches were conducted on the topics of hyponatraemia and vasopressin receptor antagonists, using PubMed, pharmaceutical company websites and news reports. The information was evaluated for relevance and quality, critically assessed and summarized.

RESULTS AND DISCUSSION

The initial treatment of severe hyponatraemia is directed towards the prevention or management of neurological manifestations and consists of an intravenous infusion of hypertonic saline. Fluid restriction is indicated in oedematous states. Diuretics alone or in combination with other specific drugs remain the main strategy in the management of volume overload in heart failure. In resistant cases, ultrafiltration can lead to effective removal of isotonic fluid preventing new episodes of decompensation; however, aquapheresis is associated with increased costs and other limits. In several trials, the efficacy of vasopressin receptor antagonists in euvolaemic patients (inappropriate antidiuretic hormone secretion) or in hypervolaemic hyponatraemia (chronic heart failure, cirrhosis) has been evaluated. It was found that vaptans, which promote aquaresis, were superior to a placebo in raising and maintaining serum sodium concentrations in these subjects.

WHAT IS NEW AND CONCLUSIONS

Combined with conventional therapy, vasopressin receptor antagonists (AVP-R antagonists) are able to increase the excretion of electrolyte-free water and the sodium concentration. Further studies are needed to assess efficacious outcomes of aquaresis compared with aquapheresis and with conventional therapy.

Hormonal changes during menopause and the impact on fluid regulation

Reproductive surgeries leave women more susceptible to postoperative hypervolemic hyponatremia because during this period women can retain water at an accelerated pace and much faster than they do sodium. This review proposes that estrogen and progestogen exposure play an important role in the increased risk of hyponatremia in menopausal women. Estrogen and progesterone exposure have important effects on both body fluid regulation and cardiovascular function and both of these reproductive hormones impact blood pressure responses to sodium loads. This article provides information on the effects of female reproductive hormones and hormone therapy (HT) on fluid regulation and cardiovascular function during menopause. Thirst- and fluid-regulating hormones respond to both osmotic and volume stimuli. Aging women maintain thirst sensitivity to osmotic stimuli but lose some thirst sensitivity to changes in central body fluid volume. Thus, older adults are more at risk of dehydration because they may replenish fluids at a slower rate. Estrogen therapy increases osmotic sensitivity for mechanisms to retain body water so may help menopausal women control body fluids and avoid dehydration. Some progestogens can mitigate estradiol effects on water and sodium retention through competition with aldosterone for the mineralocorticoid receptor and attenuating aldosterone-mediated sodium retention in the distal tubule. However, some progestogens can increase cardiovascular risks. Appropriate balance of these hormones within HT is important to avoid the negative consequences of body fluid and sodium retention, including edema and hypertension.

Syndrome of inappropriate antidiuretic hormone secretion: Revisiting a classical endocrine disorder

Hyponatremia occurs in about 30% of hospitalized patients and syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a common cause of hyponatremia. SIADH should be differentiated from other causes of hyponatremia like diuretic therapy, hypothyroidism and hypocortisolism. Where possible, all attempts should be made to identify and rectify the cause of SIADH. The main problem in SIADH is fluid excess, and hyponatremia is dilutional in nature. Fluid restriction is the main stay in the treatment of SIADH; however, cerebral salt wasting should be excluded in the clinical setting of brain surgeries, subarachnoid hemorrhage, etc. Fluid restriction in cerebral salt wasting can be hazardous. Sodium correction in chronic hyponatremia (onset >48 hours) should be done slowly to avoid deleterious effects in brain.

Syndrome of inappropriate antidiuretic hormone secretion in a cat

A 3-year-old, spayed female, domestic shorthaired cat was presented for evaluation of liver disease. Following anesthesia, laparoscopy, and medical therapy, the cat developed severe hyponatremia that was unresponsive to fluid therapy. Further evaluation of serum and urine osmolality determined that the cat fulfilled the criteria for syndrome of inappropriate antidiuretic hormone secretion. Treatment with fluid restriction resulted in resolution of the hyponatremia and clinical signs associated with the electrolyte imbalance.

Perioperative fluid management

Many colorectal surgeons rely on traditional theories and approaches in addressing perioperative fluid management issues. Often, their training and instincts favor over-resuscitation, especially after bowel or emergent colorectal procedures. However, data are now emerging to support the use of more restrictive approaches to perioperative fluid administration-though uncertainties still exist as to which fluids are optimal, and how and when they should be administered. This article provides a focused, evidence-based review on this topic-highlighting critical considerations that clinicians may wish to address to improve patient outcomes following colorectal surgery.

Perioperative fluid management: current consensus and controversies

The scientific knowledge base that supports clinical decisions about perioperative fluid management continues to evolve. However, despite these advancements in the understanding of the physiology of fluid replacement, the definition of ''optimal'' perioperative fluid management remains a matter of clinical judgment. With an appreciation of the many factors, both sensible and insensible, that contribute to changes in blood and extracellular fluid volume during surgery, clinicians have tried to create reproducible and generally applicable formulas for replacement of fluid during surgery. These formulas have been challenged recently by the introduction of new tools for monitoring cardiopulmonary function, by the implementation of monitor-guided protocols for fluid management, and, more recently, by clinical data suggesting that fluid restriction may improve surgical outcomes in some clinical settings. The relative ease of pre-identified fluid replacement protocols is being slowly replaced by data-guided interventions that take into account a variety of factors. Clinicians are therefore required to tailor their fluid replacement strategies based on preoperative patient characteristics, the type of surgery and even the type of anesthetic that is utilized. Some of the benefits of this new approach range from relatively ''minor'' outcomes such as diminished nausea after surgery to preventing postoperative complications such as wound breakdown and cardiopulmonary failure.

Changes in serum sodium, sodium balance, water balance, and plasma hormone levels as the result of pelvic surgery in women

Postoperative hyponatremia in women has been associated with the development of serious neurological disorders and even death, with a predisposition for menstruant women. The objective of this study was to evaluate the immediate hormonal, water and electrolyte responses to pelvic surgery in both pre and postmenopausal women. Of the twenty-five consecutive women studied, twenty were premenopausal while five were postmenopausal. Mean age was 45.4 +/- 1.6 years. Measurements of plasma renin activity, follicular stimulating hormone and luteinizing hormone showed no significant change pre to postoperatively. There was a significant decrease in pre to postoperative values of estrogen, 97.4 +/- 20.3 to 36.3 +/- 7.5 pg/mL (p < 0.05). There was also a significant decline in postoperative values for plasma aldosterone and plasma progesterone. Data were similar in pre and postmenopausal patients. Serum sodium levels decreased from 141.5 +/- 0.5 to 137.2 +/- 0.5 mEq/L (p < 0.01). During the twenty-four hours following surgery, mean net sodium balance was positive 122 mEq and mean measured fluid balance was positive 1108 mL. Ringers lactate or normal saline were used. On the first postoperative day, plasma arginine vasopressin levels were elevated at 4.0 +/- 0.8 pg/mL, with a mean urine osmolality of 504 +/- 29 mOsm/kg H2O. The data illustrate that women undergoing pelvic surgery decrease their serum sodium in the immediate postoperative period. Despite both positive sodium and water balance, there is a stronger tendency to conserve water. Decreased estrogen levels occur and this decrease may facilitate brain cell adaptation to plasma hypotonicity. Since the administration of isotonic fluid will not protect against the decrease in serum sodium, postoperative sodium concentration should be carefully monitored.

Effects of anesthesia, surgery, and intravenous administration of fluids on plasma antidiuretic hormone concentrations in healthy dogs

OBJECTIVE

To evaluate effects of anesthesia, surgery, and intravenous administration of fluids on plasma concentrations of antidiuretic hormone (ADH), concentration of total solids (TS), PCV, arterial blood pressure (BP), plasma osmolality, and urine output in healthy dogs.

ANIMALS

22 healthy Beagles.

PROCEDURE

11 dogs did not receive fluids, and 11 received 20 ml of lactated Ringer's solution/kg of body weight/h. Plasma ADH adn TS concentrations, PCV, osmolality, and arterial BP were measured before anesthesia (T0) and after administration of preanesthetic agents (T1), induction of anesthesia (T2), and 1 and 2 hours of surgery (T3 and T4, respectively). Urine output was measured at T3 and T4.

RESULTS

ADH concentrations increased at T1, T3, and T4, compared with concentrations at T0. Concentration of TS and PCV decreased at all times after administration of preanesthetic drugs. Plasma ADH concentration was less at T3 in dogs that received fluids, compared with those that did not. Blood pressure did not differ between groups, and osmolality did not increase > 1% from To value at any time. At T4, rate of urine production was less in dogs that did not receive fluids, compared with those that did.

CONCLUSIONS AND CLINICAL RELEVANCE

Plasma ADH concentration increased and PCV and TS concentration decreased in response to anesthesia and surgery. Intravenous administration of fluids resulted in increased urine output but had no effect on ADH concentration or arterial BP. The causes and effects of increased plasma ADH concentrations may affect efficacious administration of fluids during the perioperative period in dogs.

Arginine vasopressin disposition in the conscious rabbit

To characterize the urinary kinetics of AVP, and the influence of regional blood flow on the metabolic degradation of AVP, multiple doses of AVP were administered to conscious rabbits. AVP systemic clearance (ClT) was not influenced by changes in dose, in spite of a decrease in AVP urinary clearance following the highest dose. Hepatic blood flow was inversely associated with AVP concentrations, and despite a decrease in hepatic plasma flow of 37% (p < 0.05), following the high dose of AVP, ClT remained unchanged. These results indicate that AVP plasma kinetics are first order and plasma flow independent, and urinary kinetics are zero order.

Inappropriate fluid response in congenital diaphragmatic hernia: first report of a frequent occurrence

Safe management of the newborn infant with congenital diaphragmatic hernia (CDH) requires precise fluid administration to avoid hypovolemia or fluid overload. Twenty-two CDH patients and 12 infants who underwent abdominal operations were studied for three postoperative days to determine whether the postoperative neonatal renal response to fluid administration was appropriate or inappropriate. Each response was categorized, on the basis of urine and blood measurements, as: (1) appropriate urine output and concentration, (2) inappropriate urine output and concentration with fluid retention or (3) renal failure. Fluid intake was similar in all groups. The CDH group had a significantly lower urine output, higher urine osmolarity, and lower serum osmolarity. All of the control group (100%) responded appropriately to intake. Sixty-four percent of the CDH group inappropriately retained water during the first 16 hours (appropriate, 27%; renal failure, 9%). By 24 hours, 34% still had inappropriate urine output and fluid retention. The majority of patients with CDH initially responded inappropriately to postoperative fluid intake. If this response is not recognized and fluid intake is not adjusted, serious fluid overload will result.

Relative density of urine: methods and clinical significance

The physical properties and chemical composition of urine are highly variable and are determined in large measure by the quantity and the type of food consumed. The specific gravity is the ratio of the density to that of water, and it is dependent on the number and weight of solute particles and on the temperature of the sample. The weight of solute particles is constituted mainly of urea (73%), chloride (5.4%), sodium (5.1%), potassium (2.4%), phosphate (2.0%), uric acid (1.7%), and sulfate (1.3%). Nevertheless, urine osmolality depends only on the number of solute particles. The renal production of maximally concentrated urine and formation of dilute urine may be reduced to two basic elements: (1) generation and maintenance of a renal medullary solute concentration hypertonic to plasma and (2) a mechanism for osmotic equilibration between the inner medulla and the collecting duct fluid. The interaction of the renal medullary countercurrent system, circulating levels of antidiuretic hormone, and thirst regulates water metabolism. Renin, aldosterone, prostaglandins, and kinins also play a role. Clinical estimation of the concentrating and diluting capacity can be performed by relatively simple provocative tests. However, urinary specific gravity after taking no fluids for 12 h overnight should be 1.025 or more, so that the second urine in the morning is a useful sample for screening purposes. Many preservation procedures affect specific gravity measurements. The concentration of solids (or water) in urine can be measured by weighing, hydrometer, refractometry, surface tension, osmolality, a reagent strip, or oscillations of a capillary tube. These measurements are interrelated, not identical. Urinary density measurement is useful to assess the disorders of water balance and to discriminate between prerenal azotemia and acute tubular necrosis. The water balance regulates the serum sodium concentration, therefore disorders are revealed by hypo- and hypernatremia. The disturbances are due to renal and nonrenal diseases, mainly liver, cardiovascular, intestinal, endocrine, and iatrogenic. Fluid management is an important topic of intensive care medicine. Moreover, the usefulness of specific gravity measurement of urine lies in interpreting other findings of urinalysis, both chemical and microscopical.

Dehydration, antidiuretic hormone and the intravenous urogram

The efficacy and safety of attempts to dehydrate patients before intravenous urography in order to improve image quality have been called into question by several authors. Antidiuretic hormone (ADH) assays described here show that dehydration of outpatients as typically practised by radiology departments does not affect plasma ADH levels. Furthermore, the very act of contrast-agent administration causes a rapid rise in plasma ADH concentration to levels higher than would in any case be expected from modest dehydration. Since the likely effect on circulating ADH of attempted dehydration is dwarfed by the physiological response to a contrast agent, it is considered that such efforts are entirely superfluous.

Hyponatraemia in premature babies and following surgery in older children

Hyponatraemia implies water retention in excess of sodium with or without increased loss of sodium from the body; extracellular fluid volume may be increased, normal or reduced. It has many causes which are briefly reviewed. Among these is the rare syndrome of inappropriate secretion of antidiuretic hormone (SIADH). It is suggested that SIADH is often diagnosed incorrectly because the raised ADH levels are appropriate for the volume status of the child. Precision in the diagnosis is important because whilst water restriction is necessary for the treatment of SIADH, other measures including the administration of extra fluid are often required if the raised ADH is appropriate. Hyponatraemia in the newborn may be caused by prerenal failure, renal failure or renal sodium wasting which is common in premature infants. Careful control of sodium intake as well as water intake is vital in this age group. Surgery is associated with water retention, but recent studies suggest that ADH levels are raised post-operatively because of volume depletion and that present recommendations for fluid therapy during and following surgery are inadequate. The use of electrolyte-free dextrose solutions should be abandoned and more liberal use of physiological saline or colloid is recommended.

Effect of methadone on plasma arginine vasopressin level and urine production in conscious dogs

The aim of this study was to examine the effect of i.v. methadone on the plasma arginine-vasopressin (AVP) levels and urine production in 9 conscious dogs. A highly significant increase from the baseline plasma AVP values of below 3 pg/ml occurred within 5 min following methadone administration. Maximum levels were reached within 30-50 min post-injection and varied from 18.5 to 100 pg/ml. A significant decrease in urine production was not seen under these experimental conditions. Mean arterial blood pressure did not change significantly during the experiment. Apart from the partial influence of the methadone-induced respiratory acidosis, we postulate a direct relationship between i.v. administration of methadone and the increased plasma AVP levels in dogs.

Intravenous bumetanide attenuates the rise in plasma vasopressin concentrations during major surgical operations

During a study in seven patients on the endocrine response to major surgical procedures under general anaesthesia an incidental finding was that the administration of intravenous bumetanide prior to surgical stimulation led to reduced concentrations of plasma vasopressin (AVP) when compared with a control group of patients.