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At least 19 recordsLinked to original sources
PubMed1977

Transepidermal water loss in newborn infants. I. Relation to ambient humidity and site of measurement and estimation of total transepidermal water loss.

Insensible water loss (IWL) is an important factor in the thermoregulation and water balance of the newborn infant. A method for direct measurement of the rate of evaporation from the skin surface has been developed. The method, which is based on determination of the vapour pressure gradient close to the skin surface, allows free evaporation. From measurements performed on 19 newborns placed in incubators, a linear relation was found between the evaporation rate (ER) and the humidity of the environment at a constant ambient temperature. A 40% lower ER was recorded at a high relative humidity (60%) than at a low one (20%) in the incubator. At measurements on different sites of the body, a high ER was observed on the face and peripheral parts of the extremities, while ER at other sites was relatively low. By determining ER from different parts of the body and calculating the areas of the corresponding surfaces, the total cutaneous insensible water loss for the infant in question could be obtained. The transepidermal water loss (TEWL) for the whole body surface area was calculated to be 8.1 g/m2h. On the basis of measurements performed it was found that the total cutaneous insensible water loss can be estimated with a reasonable degree of accuracy by recording ER from only three easily accessible measurement points.

Birth Weight↗
PubMed1975

Correlation between mosquito repellent protection time and insensible water loss from the skin.

Insensible water loss and mosquito repellent protection time have been found to be relatively characteristic of any given individual. In a population having a biologic distribution of repellent protection period against mosquitoes, an inverse linear correlation was observed between repellent duration and insensible water loss. Doubling of insensible water loss was associated with a 20% decrease in repellent duration. Repellent penetration or evaporation but not attractiveness to mosquitoes are explanations for the observed relationship.

Adult↗
PubMed1982

Effects of forced convection of heated air on insensible water loss and heat loss in preterm infants in incubators.

To assess the effect of forced convection of heated air exchange in preterm infants in conventional incubators, we measured insensible water loss and total heat loss in preterm infants in a conventional forced convection incubator (air velocity 15 to 25 cm/second) and in a specially constructed still-air incubator (air velocity 0 to 2 cm/second) at equal operative temperature and humidity. Under the forced conditions, insensible water loss in the preterm infants increased by a mean 52% from 1.04 +/- 0.24 (mean +/- SD) to 1.58 +/- 0.51 ml/kg/hour (P less than 0.001). The ensuing increase in evaporative heat loss was partly reflected in the small but significant increase in total heat loss from 1.65 +/- 0.47 to 1.80 +/- 0.44 kcal/kg/hour (P less than 0.02). In the forced convection incubator, the increased evaporative heat loss in preterm infants was apparently partly compensated by a decreased nonevaporative heat loss. If reduction of insensible water loss is required, preterm infants should not be subjected to forced convection in incubators.

Air↗
PubMed1994

Predicting insensible water loss in premature neonates.

The insensible water loss from the skin of premature neonates in various environments can be estimated by modeling the skin as a composite membrane and applying Fick's law to each layer. Studies involving human skin development have made it possible to apply the proposed model to predict an infant's insensible water loss as a function of gestational age and postnatal age. However, the model tends to overestimate the insensible water loss particularly for gestational ages over 28 weeks. Values used in the model for the diffusivity of water through the stratum corneum were determined from adult skin rather than neonatal skin, which may be a factor in the overestimation.

Aging↗
PubMed1987

Computational model for insensible water loss from the newborn.

A mathematical model for predicting insensible water loss from the newborn infant has been developed, and its adjustable parameters have been evaluated using existing data for respiratory and transepidermal water loss components. Subsequently, the model was verified by using an independent set of available data on total insensible loss from naked infants who were not mechanically ventilated and who did not sweat. Under these conditions, the model was capable of correctly predicting the influence of ambient humidity, gestational age, and postnatal age, and in general, the predictions had a precision of +/- 14%, but they tended to underestimate insensible water loss by -16%. The straightforward algebraic form of the model makes it suitable for computerized calculations, which can be readily available at the bedside and quickly updated to account for changes in infant or environmental variables. The model is useful both for anticipating the abnormally large insensible water loss of the premature infant early in life and for computing expected changes in insensible water loss as a result of intentional manipulation of environmental factors, such as incubator temperature or supplemental humidification.

Computer Simulation↗
PubMed1979

Intravenous alimentation and insensible water loss in low-birth-weight infants.

Insensible water loss (IWL) was measured in six premature infants, between 4 and 21 days of age, by continuous weight monitoring on an electronic balance inside an incubator. Multiple measurements of IWL were made during the sequential infusion of 10% dextrose in 0.225% NaCl, 10% dextrose-amino acid solution, or 10% dextrose-amino acid and a commercial intravenous fat emulsion. Each solution was administered for three hours by constant infusion through a scalp vein needle. The order of the infusion was random and a 30- to 60-minute infusion with 5% dextrose water was given between each solution. During the infusion of 10% dextrose in 0.225% NaCl and 10% dextrose + amino acid solution, IWL was 1.0 +/- 0.8 gm/kg/hr and 1.1 +/- 0.8 gm/kg/hr, respectively. In contrast, IWL increased significantly to 1.6 +/- 0.7 gm/kg/hr when additional calories were given using the 10% dextrose-amino acid with the intravenous fat emulsion (P less than .005). There was a positive correlation between calorie intake and IWL. These data suggest that parenteral nutrition solutions with intravenous fat emulsion are rapidly metabolized and the increase in IWL is probably secondary to an increase in thermogenesis.

Enterocolitis, Pseudomembranous↗
PubMed1977

A simple device for reducing insensible water loss in low-birth-weight infants.

Insensible water loss (IWL) was measured in five premature infants, 1 to 4 days old, by multiple weighings on an electronic balance inside an incubator. The babies were studied naked before and after being covered with a transparent thermal blanket. The use of the thermal blanket produced a mean reduction of 70% in IWL and a net caloric saving of 27 kcal/kg/day. There was minimal interference with nursing care. The important caloric saving achieved from reduced vaporization of water and evaporative heat loss may be an important determinant of intact survival in the high-risk infant.

Bedding and Linens↗
PubMed1989

An analysis on the rates and regulation of insensible water loss through the eccrine sweat glands.

An analysis is presented on insensible water loss from the human body at rest through exposed skin surfaces into still air. Possible sites of moisture release are identified as the stratum corneum of the skin, free surfaces of dilute sweat liquids perpetually present in the microscopic ducts of a large population of eccrine sweat glands, and moist microvillous processes which line part of the periductal surfaces in the glands, particularly in the helical coils within the stratum spinosum of the epidermis. Water supply to the sites involves transepidermal migration across skin tissue layers, secretion and partial reabsorption of solutes and water within eccrine glands, and transport across periductal lining of eccrine glands from the surrounding connective tissues respectively. Evaporation and gas phase diffusion within eccrine ducts were modelled. Basal loss rates of water (as regulated by the ambient temperature and relative humidity and by aspects of the anatomy of and physiological factors for eccrine glands, the epidermis and the dermis) were calculated at between 1 and 20 g hr-1 at an ambient temperature of 25 degrees C and a relative humidity of 60% as an example. Such rates are significant fractions of experimental values for insensible water loss rates reported at between 4 and 35 g hr-1 in air at 22-30 degrees C and a relative humidity of 30-60%.

Eccrine Glands↗
PubMed1999

Evaluation of cutaneous insensible water loss during hyperbaric exposure in humans.

BACKGROUND: Water evaporation diminishes in high pressure environment, however it is unknown whether insensible water dissipation from the human skin falls as a function of the increased environmental pressure. We designed the present study to measure cutaneous insensible water loss at various pressures during exposure to a simulated saturation dive. METHODS: Four healthy male volunteers were exposed to eight different pressures between 1 and 18.4 atmospheres absolute (atm abs). Resting insensible water loss from the skin was measured as change in the body weight and corrected for the weight of the respiratory CO2 - O2 gas exchange and the respiratory water dissipation. RESULTS: We made an equation for the relationship between cutaneous insensible water loss and environmental pressure as: w = 14.5 X p(-0.48), where, w is cutaneous insensible water loss in g x m(-2) x h(-1), and P is the environmental pressure in atm abs. The average cutaneous insensible water loss (15.3 g x m(-2) x h(-1)) at normal atmosphere decreased (p < 0.01) to 4.2 g x m(-2) x h(-1) (reduced by 73%) during a saturation dive to 18.4 atm abs. CONCLUSION: The amount of insensible water loss estimated from the equation was comparable to that of reported observations.

Adult↗
PubMed1987

Insensible water loss and its assessment in adult patients: a review.

The nature, magnitude and factors influencing insensible water loss are discussed. A brief overview of the current practice of estimating insensible perspiration in Sweden is presented. Finally, a suggestion is put forward regarding a simplified formula for estimating insensible water loss in adult patients, based on information currently available in the literature.

Adult↗
PubMedDate not supplied

Insensible water loss from the medtronic minimax oxygenator: an In Vitro study.

The purposes of this study were to quantify the insensible water loss that occurs across the Medtronic Minimax oxygenator and to estimate the resultant rise in fluid sodium concentration.A Carmeda-coated extracorporeal membrane oxygenation circuit connected to a Medtronic Minimax Plus oxygenator was primed with normal saline and attached to a closed reservoir. The gas sweep was randomly assigned to one of three rates: 2, 5, or 10 LPM (liters per minute). Each sweep rate was run in triplicate. The sodium concentration of the circuit was assessed after 12 and 24 hours of each trial. At the end of each 24-hour run, the evaporative loss was calculated. The average insensible water losses were 6.9+/-0.4 ml/h, 16.6+/-1.5 ml/h, and 34.4+/-0.3 ml/h at gas sweep rates of 2, 5, and 10 LPM, respectively (p<0.0001). Daily evaporative water losses for the membrane can be estimated to be 82.7+/-2.2 ml for each 1 LPM of sweep gas flow for a normal saline pump flow of 300 ml/min. In a closed circuit, a faster sweep gas rate is associated with a more rapid rise in sodium concentration (p<0.0001).

Extracorporeal Membrane Oxygenation↗
PubMed1980

The effects of thermal environment on heat balance and insensible water loss in low-birth-weight infants.

To define the neutral environmental temperature and assess the effects of deviation from that temperature on insensible water loss and heat balance, 12 premature infants were studied in a conventional incubator at four different predetermined ambient temperatures. Our method combines insensible water loss measured by a continuous read-out electronic scale with heat production as determined by open circuit measurement of oxygen consumption. An increase of 1 to 2 degrees C, to an ambient temperature above or near the top of the neutral zone, produced a significant rise in insensible water loss, from 1.90 +/- 0.76 to 3.08 +/- 1.19 ml/kg/hour (mean +/- SD), a corresponding rise in evaporative heat loss, and a fall in nonevaporative heat loss. A decrease of 1 to 2 degrees C, to a slightly subneutral ambient temperature, resulted in an increase in oxygen consumption from 5.82 +/- 0.92 to 7.45 +/- 1.50 ml/kg/minute, and an increase in total heat loss, but no change in insensible water loss and evaporative heat loss. The increased total heat loss was judged to be due entirely to a greater nonevaporative heat loss, both by convection and by radiation. The data confirm that ambient temperature is an important determinant of the magnitude and the partition of heat loss in low-birth-weight infants.

Body Temperature Regulation↗
PubMed1981

Radiant warmer power and body size as determinants of insensible water loss in the critically ill neonate.

Twelve critically ill neonates mechanically ventilated for respiratory failure (mean weight 1.33 kg, mean gestation 31 wk) were studied to quantitate the effects of radiant power from a radiant warming device, body weight, and body surface area on insensible water loss. Radiant power density (Mw/cm2) was measured using a wattmeter and thermopile transducer. Insensible water loss was measured using a Potter Baby Scale. Weight correlated inversely with insensible water loss, (r = -0.86, P less than 0.001). Radiant power density correlated inversely to weight, (r = -0.71, P less than 0.001). There was a significant increase in insensible water loss as radiant power density increased, (r = 0.54, P less than 0.05). Net radiant power received (W/kg) by infants over their exposed surface area, correlated directly to insensible water loss, (r = 0.67, P less than 0.01) irrespective of body weight. Critically ill neonates ventilated for respiratory failure and nursed under radiant warmers incurred greater insensible water losses than previously reported for well infants. The magnitude of this increased insensible water loss is inversely related to body size and is determined directly by the radiant power density required to maintain body temperature.

Apnea↗
PubMed1991

Insensible water loss in resting adults in Kandy, Sri Lanka.

Sixty three adults (44 men) were observed over a 4 hour period in Kandy to measure insensible water loss. Six adult men were similarly studied over 24 hours. The average loss per day, computed from the 4 hour studies was 1,333 ml for men and 1,230 ml for women. The 24 hour study showed an average loss of 1,423 ml. A reasonable working estimate for insensible water loss for resting adults in Kandy would be about 1,000 to 1,200 ml per day. However, when renal excretion of water is impaired, it is safer to err on the side of mild dehydration than to attempt complete hydration.

Adult↗
PubMed1981

Insensible water loss in the critically III neonate. Combined effect of radiant-warmer power and phototherapy.

To quantitate radiant power and insensible water loss under phototherapy, 12 neonates were studied under radiant warmers for one hour each with and without phototherapy. Warmer power was measured by wattmeter and thermopile. Power density received from phototherapy was 4.4 mW/sq cm. Addition of phototherapy to the servocontrolled warmer caused a disease in power density received from the warmer (17.1 to 12.9 mW/sq cm). However, the total radiant-power density received with phototherapy and the warmer combined (17.3 mW/sg cm) did not differ from net power density received without phototherapy (17.1 mW/sq cm). Insensible water loss, measured with a metabolic balance, increased from 2.54 to 3.73 mL/kg/hr, with addition of phototherapy. Since the total radiant-power density did not change, mechanisms other than increased radiant-power delivery must exist to explain the increased insensible water loss observed with phototherapy.

Female↗
PubMed1980

[Electrolyte balance in major abdominal surgery. III. On insensible water losses from the peritoneal cavity (author's transl)].

Two groups of 16 patients each were studied during abdomino-surgical procedures. Patients of one group received an isotonic glucose solution to cover insensible water losses from the peritoneal cavity whilst patients of the other group were not treated with glucose. In these we found a significant increase in plasma osmolality and in mean corpuscular hemoglobin concentration of the red cells during anaesthesia and operation. The balance of osmotic free water was calculated from changes of plasma osmolality during the observation period. Calculating output as difference between known input and balance we found losses of osmotic free water amounting to approximately 4.5 ml per kilogram bodyweight per hour of operation in both groups. These losses are, in our opinion, identical with the insensible water loss from the peritoneum. Plasma sodium concentration in both groups showed decreasing tendency compared with plasma osmolality. This was partly due to dilution with increased extracellular glucose concentration and partly to an extra-intracellular shift of sodium (without net-water-flux). Plasma potassium concentration decreased in patients receiving glucose but increased in patients without glucose. Red cell potassium concentration decreased in both groups. Urin-to-plasma ratio of osmolality was equal in both groups in spite of a different water balance. Patients receiving glucose had higher urine outputs and therefore (with equal osmolar U/P ratio) a higher osmolar clearance and a higher free-water-reabsorption. It is demonstrated that under conditions as described the amount of free-water reabsorption and concomitantly a favourable effect on water balance during mild dehydration is mainly depending on osmolar clearance.

Abdomen↗