Acute dehydration is the most common form of pediatric dehydration. Dehydration is a pathophysiological syndrome caused by the reduction of body fluid, mainly extracellular fluid, due to some pathological factors, and common pediatric emergencies, such as diarrhea and vomiting, can lead to pediatric dehydration. Body fluids are an important part of the human body, and maintaining the physiological balance of body fluids is one of the important conditions for maintaining normal physiological activities of the human body.
The dynamic balance of water, electrolytes, pH and osmolality in body fluids depends on the normal regulation of neurological, endocrine, digestive, respiratory and urinary systems. Body fluids are divided into two parts: extracellular fluid and intracellular fluid. The extracellular fluid is distributed in the lumen of blood vessels and the interstitial area of tissue cells. The younger the child, the more the total body fluid is relatively high, mainly because the proportion of interstitial fluid in the extracellular fluid is higher.
Due to the physiological characteristics of children, such as the underdeveloped kidney function, the digestive and respiratory systems are susceptible to infection by pathogens, the functions of these systems are highly susceptible to disorders caused by diseases and external environment, and disorders of water, electrolyte and acid-base balance are extremely common in pediatric clinics. In dehydration, the child loses sodium, potassium and other electrolytes in addition to water.
The severity of fluid and electrolyte loss depends on the rate and magnitude of loss, and the type of fluid and electrolyte loss reflects the relative rate of loss of water and electrolytes (mainly sodium). The main treatment for dehydration is fluid therapy, and the etiology of dehydration, as well as the degree and nature of dehydration, are the main basis for fluid therapy. Therefore, in order to improve the success rate of treatment, clinicians should pay attention to evaluating and judging the etiology, degree and nature of dehydration before implementing treatment measures for dehydrated children.
I. Clinical diagnosis and evaluation
1.Clinical manifestations
Clinical manifestations of the primary disease Dehydration is a pathophysiological syndrome caused by the reduction of body fluid loss, and paying attention to the clinical manifestations of the primary disease can help find the cause of dehydration and help cure the disease. Different primary diseases have their own clinical manifestations, such as diarrhea for enteritis and vomiting for gastritis.
The primary cause of dehydration can directly affect the nature of water-electrolyte disorders in children, such as the loss of alkaline fluid from the intestine in diarrhea and the loss of acidic fluid from the stomach in vomiting.
3 Clinical manifestations of dehydration Dehydration can cause changes in the neurological and mental status of the child, causing the child to have sunken fontanelle and eye sockets, dryness and poor elasticity of the skin and mucous membranes, and in severe cases, leading to low urination, poor peripheral circulation and metabolic acidosis. The clinical manifestations of different nature and degree of dehydration are different, so clinicians need to make comprehensive clinical analysis and judgment to accurately and comprehensively evaluate the condition in order to carry out effective and timely treatment.
Clinical evaluation
1.Clinical evaluation of the degree of dehydration
The degree of dehydration is often evaluated by the percentage of fluid loss to body weight. Children often have a history of fluid loss and signs of dehydration, and if the patient has no recent weight records, the percentage of weight loss can often be estimated through physical examination and medical history. The percentage of weight loss can often be estimated by physical examination and history taking if the patient has no recent weight record.
The degree of dehydration is often divided into three degrees.
① Mild dehydration: The child has a reduction of 3-5% of body weight or equivalent to 30-50ml/kg of body fluid. The clinical manifestations are slightly poor in spirit, slightly irritable and restless; physical examination shows slightly dry skin, still elastic, slightly sunken eye sockets and fontanel; tears when crying, slightly dry mucous membrane of mouth and lips, slightly reduced urine volume.
②Moderate dehydration: the child has 5-10% weight loss or the equivalent of fluid loss of 50~lOOml/kg. clinical manifestations are depression or restlessness; the skin is pale, dry and less elastic, the eye sockets and fontanelle are obviously sunken, there are few tears when crying, the mucous membranes of the mouth and lips are dry; the limbs are slightly cold and the urine volume is obviously reduced.
(3) Severe dehydration: the child has more than 10% weight loss or the equivalent of 100-120 ml/kg of body fluid loss. clinical manifestations are the child is seriously ill, extremely depressed, indifferent expression, lethargy or even coma; the skin is gray or patterned, elasticity is very poor; eye sockets and fontanelle deep sunken, eye closure does not fit, both eyes stare, no tears when crying; the mucous membrane of the mouth and lips is extremely dry. Due to the obvious reduction of blood volume, shock symptoms may appear, such as low heart sound, fine and rapid pulse, decreased blood pressure, cold extremities, very little urine or even no urine.
2. Clinical evaluation of the nature of dehydration
In dehydration, both water and electrolytes are lost, but the ratio of water and electrolyte (mainly sodium) loss can be different for dehydration caused by different etiologies, resulting in different changes of body fluid osmolality. The assessment of the nature of dehydration is mainly based on the alteration of the existing body fluid osmolality, which reflects the relative loss of water and electrolytes, and is often assessed clinically based on the detection levels of serum sodium and plasma osmolality.
Serum electrolytes and plasma osmolality are often correlated with each other, as osmolality is largely dependent on the level of serum cations, i.e. sodium ions. The nature of dehydration can be divided into 3 types: isotonic, hypotonic and hypertonic dehydration, with isotonic dehydration being the most common, followed by hypotonic and hypertonic dehydration being rare. The nature of dehydration is often determined clinically by the determination of serum sodium, the child’s medical history and the characteristics of clinical manifestations.
Clinical manifestations vary depending on the severity of dehydration, and largely depend on the amount of extracellular volume lost.
② hypotonic dehydration: the serum sodium ion concentration of the child is lower than 130 mmol/L. At this time, water enters from extracellular to intracellular, so that the circulating volume is lost outside the body and is further reduced by the transfer of water to intracellular, and in severe cases, a drop in blood pressure can occur and shock is likely to occur. Due to the drop in blood pressure, reflex constriction of visceral blood vessels occurs, renal blood flow decreases, glomerular filtration rate decreases, urine output decreases, and azotemia occurs.
Another consequence of the reduced glomerular filtration rate is that the sodium ions entering the renal tubules are reduced, thus sodium is almost completely reabsorbed, and the increased secretion of aldosterone caused by the reduced plasma volume makes the sodium reabsorption more complete. If hypotonic fluids continue to be supplemented, serious consequences such as water intoxication and cerebral edema can occur. Since the degree of reduction of extracellular fluid in hypotonic dehydration is relatively more obvious than the other two types of dehydration, the clinical manifestations are more serious.
Initially, there may be no symptoms of thirst, and in addition to general dehydration phenomena such as decreased skin elasticity, sunken eye sockets and fontanelle, there are mostly shock symptoms such as cold extremities, blossoming skin, decreased blood pressure and decreased urine output. Due to reduced circulating blood flow and tissue hypoxia, brain cell edema may occur in severe hyponatremia, so there are mostly drowsiness and other neurological symptoms, and even convulsions and coma may occur. When accompanied with acidosis, there are often deep breathing; when accompanied with hypokalemia, weakness, abdominal distension, intestinal obstruction or cardiac arrhythmia may occur; when accompanied with hypocalcemia and hypomagnesia, muscle twitching, convulsions and electrocardiogram abnormalities may occur.
③ in hypertonic dehydration : the serum sodium ion concentration of the child is greater than 150mmol/L, at this time, water is transferred from intracellular to extracellular so that the osmotic pressure inside and outside the cell reaches equilibrium, the result is that the intracellular volume is reduced. At this time, because the extracellular fluid is supplemented by intracellular fluid, the clinical signs of dehydration are not obvious, and the skin is often warm and has a rubbing sensation; the nervous system may show drowsiness, but the muscle tone is high and the reflexes are active.
Due to the high sodium concentration of extracellular fluid and increased osmolarity, the antidiuretic hormone in the body increases and the kidneys reabsorb more water, as a result, the urine volume decreases. When the osmolarity of extracellular fluid is increased, water is leaked out from the cells to regulate the osmolarity inside and outside the cells, and as a result, the intracellular fluid is reduced. Because the decrease in extracellular fluid is not severe, both circulatory failure and reduced glomerular filtration rate are less severe than the other two types of dehydration.
Due to intracellular dehydration, children often show intense thirst, high fever, irritability, increased muscle tone, and even convulsions. Since the burden on the kidneys increases significantly after dehydration, it is necessary to absorb as much water as possible and at the same time to excrete waste from the body, and if dehydration continues to increase, azotemia will eventually appear.
3.Clinical evaluation of metabolic acidosis
Normal children’s blood pH is 7.4 like adults, but its range is slightly wider, i.e. 7.35~7.45. pH value less than 7.35 is acidosis, and acidosis caused by dehydration is mostly metabolic acidosis.
The body body regulates the pH at a more stable level depending on two mechanisms.
① physicochemical or buffering mechanism, which can prevent excessive acid or base loss.
② Physiological mechanisms, mainly the kidneys and lungs and other organs are directly involved in buffering and regulating mechanisms, which make the buffering mechanism work more effectively.
The buffering system of blood and other body fluids consists of two main aspects: the carbonate, bicarbonate system and the non-bicarbonate system.
In the blood non-bicarbonate buffer system, it is mainly hemoglobin, organic and inorganic phosphorus, with plasma proteins accounting for a smaller fraction. In the interstitial fluid, there is almost no non-bicarbonate buffering system. In the intracellular fluid, carbonate, bicarbonate and non-carbonate buffering systems all play a role, the latter consisting mainly of organophosphorus proteins and other components.
Metabolic acidosis occurs as a result of.
① loss of large amounts of alkaline substances from vomiting and diarrhea, less food, insufficient calories, poor intestinal absorption, and lack of normal energy supply to the organism leading to increased lipolysis and production of large amounts of ketone bodies.
(2) Decrease in blood volume, blood concentration, slow blood flow and tissue hypoxia cause lactic acid accumulation during dehydration.
(3) Dehydration causes insufficient renal blood flow and low acid and sodium retention capacity, resulting in retention of acidic metabolites in the body. The child may show symptoms such as mental depression, cherry red mouth and lips, deep breathing and ketone smell in exhaled gas, but the symptoms can be very atypical in small infants.
4. Clinical evaluation of abnormal potassium metabolism
III. Hypokalemia
Potassium in human body mainly exists in cells, and normal serum potassium is maintained at 3.5~5.0mmol/L, which plays an important role in regulating various functions of cells. When the serum potassium concentration is lower than 3.5 mmol/L, it is called hypokalemia. The potassium content of gastrointestinal fluid is high (about 17.9±11.8 mmol/L in the stool during diarrhea), and vomiting and diarrhea result in the loss of large amounts of potassium salts;
With less food and insufficient intake, the kidneys have poorer potassium retention than sodium retention, and a certain amount of potassium continues to be excreted in the absence of potassium, so there is often a lack of potassium in the body when dehydration occurs. However, before dehydration is corrected, the total amount of potassium in the body is reduced due to blood concentration, transfer of potassium from intracellular to extracellular during acidosis, and reduced potassium excretion due to low urination, but most of the serum potassium is normal.
As dehydration and acidosis are corrected, potassium excretion increases after urination, and potassium loss continues in stool and is consumed during glucose input for glycogen synthesis, the blood potassium drops rapidly. The electrocardiogram may show lower ST segment, flat or inverted T wave, prolonged QT interval, and U wave, and the U wave is higher than the T wave in the same lead.
The main reasons for the occurrence of hypokalemia are.
①Insufficient intake of potassium;
(2) Excessive loss from the digestive tract, such as vomiting, diarrhea, various kinds of drainage or frequent enemas without timely replenishment of potassium;
(3) Excessive renal excretion; for example, potassium is released from the cells due to acidosis, and then excreted in large quantities by the kidneys. When a solution without potassium is input, potassium is excreted with the increase of urine volume because plasma is diluted; potassium is transferred to the cells after acidosis is corrected; potassium can be consumed during glycogen synthesis. Due to the above reasons, the serum potassium decreases and symptoms of low potassium appear.
④ Abnormal distribution of potassium in the body: for example, in familial periodic paralysis, the patient develops hypokalemia due to rapid transfer of potassium from extracellular fluid to intracellular. ⑤ Alkalosis of various causes.
The clinical manifestations of hypokalemia are determined not only by the concentration of potassium in the blood but, more importantly, by the rate at which potassium deficiency occurs. When serum potassium falls by lmmol/L, the total potassium in the body has fallen by 10-30%. Most of the children can tolerate it at this time; in the case of slow onset, although the potassium deficiency in the body reaches a serious level, the clinical symptoms are not necessarily very severe.
Symptoms generally appear when the serum potassium is below 3 mmol/L.
They include.
①Neuromuscular: decreased neuromuscular excitability, manifested as changes in skeletal muscle, smooth muscle and cardiac muscle function, such as muscle weakness, or in severe cases, respiratory muscle paralysis or paralytic intestinal obstruction, gastric dilatation; weakened or disappeared knee reflex and abdominal wall reflex.
②Cardiovascular system: heart rhythm disorders, reduced myocardial contractility, lower blood pressure, and even heart failure; ECG manifests as low and wide T waves, U waves, prolonged Q-d interval, T-wave inversion, and ST-segment decrease, etc.
(3) Renal function damage: low potassium causes the kidney concentration function to decrease, polyuria, and in severe cases, alkalosis symptoms. Long-term hypokalemia can lead to sclerosis of renal units and interstitial fibrosis, which are pathologically difficult to distinguish from chronic pyelonephritis. In addition, chronic hypokalemia can lead to a decrease in growth hormone secretion.
1.Hyperkalemia
When the serum potassium concentration is ≥5.5 mmol/L, it is called hyperkalemia. Improper rehydration during dehydration can cause medically induced hyperkalemia, which can even be life-threatening, therefore, it is an important rehydration principle to see urinary rehydration.
The main causes of hyperkalemia are.
(1) Decreased potassium excretion due to renal failure, tubular acidosis, adrenocortical hypofunction, etc;
(2) Abnormal potassium distribution due to shock, severe hemolysis and severe crush injury;
(3) The speed or concentration of the potassium-containing solution is too high.
Clinical manifestations of hyperkalemia.
①Electrocardiogram abnormalities and cardiac rhythm disturbances: In hyperkalemia, the heart rate is slowed and irregular, and premature ventricular beats and ventricular fibrillation may occur, or even cardiac arrest. The ECG may show elevated T waves, disappearance of P waves or widening of QRS waves, ventricular fibrillation and cardiac arrest. The abnormalities of the ECG are the most important basis for deciding whether the child needs treatment against hyperkalemia.
(2) Neurological and muscular symptoms: In hyperkalemia, the child is depressed, drowsy, has abnormal sensation in the hands and feet, and the tendon reflexes are weakened or disappeared; in severe cases, flaccid paralysis, urinary retention, or even respiratory paralysis may occur.
2.Diagnosis and differential diagnosis
3.Diagnosis
The main basis for the diagnosis of dehydration is the presence of the cause of dehydration and the clinical manifestations of dehydration in the child. The diagnosis of dehydration includes: (1) diagnosis of the primary cause; (2) diagnosis of the degree of dehydration; (3) diagnosis of the nature of dehydration; (4) diagnosis of disorders of the water and electricity media, such as acidosis, hyperkalemia, hypokalemia, etc.
A detailed history often provides information for estimating the nature and degree of water loss, so the patient should be asked in detail about intake and excretion, weight change, number and frequency of urination, general condition and changes in the child’s temperament. When a child has had diarrhea for several days and has normal water intake with minimal sodium intake, he or she often presents with hypotonic dehydration;
Hypernatremia can occur when there is hypertension for several days with little water intake, when formula is incorrectly formulated to be hypertonic or when hypertonic fluids are used; hyponatremia can occur when diuretics are used, when renal salt loss factors are present, and when intake is inadequate. However, hypertonic dehydration may also occur when the child has primary or secondary nephrogenic enuresis and water intake is limited. The stools of diarrhea are usually hypotonic, and with the partial oral supplementation of hypotonic fluids, the final dehydration is isotonic.
4.Differential diagnosis
The differential diagnosis of dehydration includes.
①Differential diagnosis of the original disease;
②Differential diagnosis of the degree of dehydration;
③Differential diagnosis of the nature of dehydration;
④Differential diagnosis of disorders of water and electricity media, such as acidosis, hyperkalemia, hypokalemia, etc.
The clinical signs between mild, moderate and severe dehydration often overlap, and the loss of fluid per unit body weight is sometimes difficult to estimate precisely, so the clinical diagnosis can be summarized by “mild to moderate dehydration” or “moderate to severe dehydration”. It should be noted that the degree of dehydration is often overestimated when severe malnutrition is present in the child. The sunken eye sockets are often detected by parents, and their recovery is often one of the earliest signs of improvement after rehydration.
IV. Clinical treatment and evaluation
1.The purpose of etiological treatment is to control the original disease that causes dehydration, and take different treatment measures for different etiologies.
2.Fluid therapy
3.The principles of fluid therapy
Fluid therapy is an important part of pediatric medicine, the purpose of which is to maintain or restore the normal volume and composition of body fluids to ensure normal physiological function.
The general therapeutic principles of fluid therapy can be summarized as follows.
①Timing, qualitative, quantitative and rapid;
②Save life first, then remove the cause of the disease;
③Salt first, then sugar, first fast, then full, first thick, then light, rather less than more;
④Replenish potassium when you see urine and calcium when you see shock, and adjust in time;
⑤ Close observation, timely management of complications, correction of acidosis and water-electrolyte disorders.
In general, the kidney, lung, cardiovascular and endocrine systems have a strong regulating effect on the fluid balance in the body, so if the composition and amount of rehydration fluid are basically appropriate, the body can fully adjust to restore the normal balance of body fluids; however, if the above organs are dysfunctional, the composition of fluid should be more strictly selected, and the amount and rate of rehydration fluid should be selected according to their pathophysiological characteristics and adjusted according to the changes of the disease.
Fluid therapy includes the replenishment of physiological needs, cumulative losses and continued losses. Each of these components can be calculated and replenished independently. Since the causes and nature of fluid imbalance are very complicated, it is necessary to fully grasp the medical history, physical examination and experimental data and the individual differences of children when formulating the rehydration plan, analyze the different needs of the three parts of fluid, and determine the reasonable and correct amount, speed, composition and order of infusion.
4.Supplementation of physiological requirements
Physiological requirements involve calories, water and electrolytes. The amount of maintenance fluid and electrolytes are directly related to the metabolic rate, and changes in the metabolic rate can affect the production of endogenous water through carbohydrate, fat and protein oxidation, and solute excretion from the kidney can affect the excretion of water. 25% of water is lost through unmanifest water loss, and the production of energy will certainly affect the loss of water, so the estimation of normal physiological needs can be calculated according to the energy demand, generally according to each metabolic lOOkcal Energy needs 100-150ml of water;
The younger the age, the more water is needed, so it can also be calculated according to the simple calculation table. Physiological requirements depend on urine volume, stool loss and non-obvious water loss. The physiological requirement should be supplemented orally as much as possible, and those who cannot take orally or are insufficient can be given 1/4 to 1/5 of sodium solution intravenously, while giving the physiological requirement of potassium. Children with fever and rapid respiration should increase the amount of fluid intake appropriately; malnourished people should pay attention to energy and protein supplementation, and use partial or total intravenous nutrition if necessary.
Supplementation of physiological requirements should be considered including 3 aspects of calories, fluid volume and electrolytes.
①Calories: supply with glucose solution. The first day of fluid replenishment should try to supply the calories required for basal metabolism, 230-250KJ/K (50-60kcal/kg) per day for infants and children, and replenishing enough calories can reduce the consumption of fat and protein and other tissues.
②Liquid volume: The daily fluid intake should supply the non-obvious water loss from lung and skin volatilization or water loss from sweat, urine, stool, etc. The non-obvious water loss accounts for about 1/3 of the fluid loss, which increases when fever is present. In the case of fasting, in order to meet the basal metabolic needs, the daily supply of fluid is about 70-100ml/K.
③Electrolytes: the amount of physiologically required electrolytes should be supplemented orally as much as possible, and those who cannot take orally or the oral amount is insufficient can be given 1/4 to 1/5 Zhang sodium-containing solution intravenously. Children with fever, rapid respiration and convulsions should increase water intake appropriately, and children with long-term infusion or combined malnutrition should pay more attention to the supplementation of calories and proteins, and if necessary, partial or total intravenous nutrition solution can be used.
5.Supplementation of accumulated loss
In other words, the total amount of water and electrolyte loss that existed in the child before treatment should be replenished, and according to the degree and nature of dehydration, quantitative, regular and rapid replenishment should be given.
①Quantity: The amount of rehydration is determined according to the degree of dehydration. Mild dehydration is about 30-50ml/K; moderate dehydration is about 50-100ml/K; severe dehydration is about 100-150ml/kg. 1/2 to 2/3 of the total amount should be given first.
②Quality: The type of rehydration fluid is determined according to the nature of dehydration. Usually, for hypotonic dehydration, 2/3 sheets of sodium-containing fluid should be given; for isotonic dehydration, 1/2 sheet of sodium-containing fluid should be given; for hypertonic dehydration, 1/3 to 1/5 sheet of sodium-containing fluid should be given; if it is clinically difficult to judge the nature of dehydration, isotonic dehydration can be given first.
③ Fixing the speed: that is, the speed of infusion. The speed of rehydration depends on the degree of dehydration, in principle, first fast and then slow. For severely dehydrated children with poor circulation and shock, isotonic sodium-containing fluid (saline or 2:1 fluid) should be rapidly infused at 20 ml/K (total volume not exceeding 300 m1) intravenously within 30 minutes to 1 hour to rapidly improve circulating blood volume and renal function, and the remaining cumulative loss should be completed within 8 to 12 hours.
Potassium supplementation should be given promptly after the onset of urination with improved circulation. For children with hypertonic dehydration, hypernatremia needs to be corrected slowly because the osmotic pressure of their intracellular fluid is high, and the rapid entry of large amounts of water into the cells can cause brain cell edema and even convulsions.
6.Replenishment of continued loss
After starting to replenish the accumulated loss, diarrhea, vomiting, gastrointestinal drainage and other losses mostly continue to exist, resulting in continued loss of body fluids, which will become a new accumulated loss if not replenished. The amount of such losses varies according to the primary disease and can change daily, which must be evaluated and supplemented with similar solutions according to the actual losses.
In children with diarrhea, it is difficult to estimate the amount of stool, so it can be evaluated according to the number of stools and the recovery from dehydration, and the amount of fluid can be increased or decreased appropriately, generally based on l0-40 ml/kg per day, with 1/3-1/2 of the fluid containing the nasal drip evenly over 24 hours. In mild cases without vomiting, oral rehydration fluid can be used. The potassium content of the digestive tract is high and should be replenished promptly when lost.
7.Correction of acidosis
Apply alkaline drugs, commonly used is sodium bicarbonate, can be taken orally or injected intravenously to correct acidosis. At the same time, find out the original disease in time and remove the cause. It should not be used in shock, hypoxia, hepatic insufficiency, neonatal period or lactic acid retention acidosis.
If there is no condition to test blood gas, 1.4% NaHC03 or 1.87% sodium lactate 1ml/kg can be given temporarily first, which can be repeated if necessary for 2-4 hours; if the result of blood gas analysis is known, it can be calculated according to the following formula:
Number of ml of 5% sodium bicarbonate = (18 – measured CO2 binding mmol/L) × 1.0 × body weight K;
11.2 ml of sodium lactate = (18 – measured carbon dioxide binding power mmol/L) × 0.6 × body weight K
Generally, isotonic sodium-containing solution was used (1.4% isotonic solution for 5% NaHC03 diluted 3.5 times; 1.87% isotonic solution for 11.2% sodium lactate diluted 6 times). Because of the compensatory regulation function of the body, most children with acidosis can be corrected without the full amount of alkaline drugs, usually the first time to give 1/2 of the calculated amount, closely observe the condition and adjust the dose at any time to avoid alkalosis caused by the oversupply of alkali.
8. Correction of electrolyte disorders
In the process of acid correction, potassium ion enters into the cell and the concentration of serum potassium is likely to drop, resulting in hypokalemia, so attention should be paid to timely potassium supplementation. Mild hypokalemia can be treated with more potassium-rich food or oral potassium chloride 3-4ml/K (20-30mg/kg) daily. In severe hypokalemia, intravenous potassium can be given at a concentration of 0.2%, not more than 0.3%, and the total daily amount can be 30-45mg/kg, which is about 10% KCl1-2ml/K, evenly distributed in the daily intravenous fluids, and the drip time should not be less than 8 hours.
During the treatment period, the changes in clinical symptoms should be closely observed and the concentration and speed of potassium-containing solution should be adjusted at any time. In cases of severe dehydration and renal dysfunction, potassium should be dilated to improve circulation and renal function, and potassium should be replaced after urine is excreted. Because of the slow recovery of intracellular potassium, treatment of hypokalemia should be continued for 4 to 6 days, and longer for severe cases or those with extrarenal potassium loss.
After the acidosis is corrected, those who have convulsions due to reduced free calcium should pay attention to calcium supplementation. 5-10 ml of 10% calcium gluconate can be added to 10-20 ml of 10% glucose solution, diluted and slowly pushed intravenously, and repeated if necessary. If no effect with calcium consider hypomagnesemia, available 25% magnesium sulfate, each 0.1 ~ 0.2ml / K, deep intramuscular injection, once every 6 hours, even 3 ~ 4 times.
Various diseases resulting in water, electrolytes and acid-base imbalance on the above three parts of the need for slightly different, of which the physiological needs are common, the latter two are dependent on the condition, such as general diseases can not eat only need to supplement the physiological needs, gastrointestinal drainage or intestinal fistula after surgery need to supplement the physiological needs and abnormal losses, and infant diarrhea are all three to supplement.
9.Fluid therapy for common pediatric diseases
10, malnutrition with diarrhea when the fluid therapy
When malnutrition, extracellular fluid is generally hypotonic, and diarrhea is prone to hypotonic dehydration, acidosis, hypokalemia and hypocalcemia. Because of the low subcutaneous fat in malnutrition, high estimation should be avoided when estimating the degree of dehydration, and the amount of rehydration should be reduced by 1/3 of the total amount, and 2/3 of the sodium-containing solution should be dripped slowly. In order to replenish heat and prevent hypoglycemia, 10%-15% glucose solution can be given intravenously, and potassium, calcium and magnesium can be added in time.
11, severe pneumonia when the liquid therapy
Pediatric pneumonia is often accompanied by hyperthermia, excessive sweating, accelerated respiration, increased caloric consumption and inadequate intake, prone to hypertonic dehydration and mixed acidosis, the infusion should pay attention to.
①Total fluid volume to ensure adequate fluid volume and caloric needs to avoid dehydration and aggravation of acidosis, the principle is to try to take orally, those who cannot take orally by intravenous supplementation, the daily fluid volume is about 60 ~ 80ml/K.
②Children with pneumonia are often accompanied by hypertonic dehydration, and can be supplemented with 1/3 of the sodium-containing liquid. If there is dehydration and metabolic acidosis complicated by diarrhea, rehydration can be carried out according to diarrhea, but the total amount and tension should be relatively reduced, and the infusion rate should be slow so as not to increase the burden on the heart.
③When accompanied with acidosis, the focus should be on correcting hypoxia and improving pulmonary ventilation. Generally, alkaline fluids are not needed, and sodium bicarbonate should be used only when the acidosis is too severe (PH<7.20) or when it is combined with metabolic acidosis at the same time, but the amount should not be too much. < font="">
12. Fluid therapy for newborns
Neonates have immature liver and kidney functions and poor ability to regulate water, electrolytes and acid-base balance, so they are prone to water-electrolyte balance disorders, but the clinical symptoms are often not obvious, so they should be asked and recorded in detail for daily fluid intake and output, closely observed and treated in time to avoid delaying the chance of rescue.
When rehydrating, attention should be paid to.
①In newborns within 10 days of birth, generally no potassium is supplemented. If there is obvious potassium deficiency and intravenous supplementation is needed, potassium must be supplemented in urine, and the concentration should not exceed 0.15%. The total amount of potassium supplementation should be 2-3 mmol/K per day, and the speed should be slow.
②The amount of infusion should be small and the speed of infusion should be slow, except for urgent expansion of blood volume, generally it should not exceed 10ml/K per hour.
(③) The liver of the newborn is slow to metabolize lactic acid, and sodium bicarbonate is used instead of sodium lactate to correct acidosis, but hypertonic sodium bicarbonate solution is prohibited.
13, oral rehydration salts (oralrehydrationsalts, ORS) application
0RS is a solution recommended by the World Health Organization for the treatment of acute diarrhea combined with dehydration, and has been clinically applied to achieve good results, especially for developing countries. Its theoretical basis is based on the Na+-glucose coupled transport and absorption mechanism of the small intestine, where there is a Na+-glucose common carrier in the membrane of the brush border of the small intestinal epithelium, and there are two binding sites for Sa+-glucose on this carrier. The Na+-glucose binding site is able to function and significantly increase the absorption of sodium and water.
Various ORS formulations are available, and the WHO recommended concentrations of various electrolytes in oral rehydration salts are Na+90 mmol/L, K+20 mmol/L, C1-80 mmol/L, HC03-30 mmol/L, and glucose 111 mmol/L. NaCl 3.5 g, NaHCO2 2.5 g, potassium citrate 1.5 g, and glucose 20.0 g can be used. 20.0g, add water to 1000ml to prepare. The osmolality of its electrolytes is 220 mmol/L (2/3 sheet) and the total osmolality is 310 mmol/L.
The concentration of glucose in this solution is 2%, which facilitates the absorption of Na+ and water; the concentration of Na+ is 90 mmol/L, which is suitable for correcting the amount of accumulated losses and the amount of electrolyte loss in feces; it contains a certain amount of potassium and bicarbonate, which can replenish potassium and correct acidosis. oRS is generally suitable for mild or moderate dehydration without severe vomiting, and can also be used to replenish the amount of continued fluid loss.