Physiological needs for water and basic ions. Physiological need for fluid in adults. Daily physical need for fluid Daily physical need for fluid. Principles of infusion therapy Physiological fluid requirements for adults
After surgery Any adult patient weighing more than 60 kg with normal kidney function should receive at least 2000 ml of fluid per day. After major surgery most fluids are administered intravenously, and the volume may be larger. In the absence of underlying renal or cardiac disease, the goal of the infusion is to provide a safe fluid load that allows homeostatic mechanisms to self-distribute fluid and remove excess fluid. The required volume of infusion is calculated by determining the physiological need for fluid and taking into account additional existing and current losses.
With normal renal function, the target is urine output of 1 ml/kg/h. Diuresis determines the physiological need for fluid. With a weight of 80 kg, diuresis should be 80 ml/h. To draw up an infusion therapy plan, it is more convenient to assume that there are 25 hours in a day. This means that this patient will need 25x80 = 2000 ml of fluid per day. In this case, it is better to be a little generous and round up the values. To finally determine the volume of daily infusion, it is necessary to take into account a number of the following factors.
Fever and intangible losses
Intangible fluid loss through the skin and lungs is called; Normally, the volume of these losses is about 50 ml/h (1200 ml/day). During the metabolism of nutrients in the body, on the contrary, water is formed; its volume is usually subtracted from intangible losses. As a result, it turns out that the volume of imperceptible losses is about 20 ml/hour (500 ml/day). For fever and high temperature environment the intensity of both processes increases. As a result, the increase in intangible losses (minus the water formed during metabolism) is 250 ml/day for each °C above 37 °C.
Losses in the "third space"
In the area of massive tissue damage, edema forms (Chapter 1). This fluid accumulated in the intersticial space does not exchange with other fluid spaces of the body. This anatomically non-existent space was called the “third” (in addition to the two real ones - extra- and intracellular). A lot of fluid can accumulate in the third space after laparotomy and thoracotomy, as well as with massive soft tissue damage. To compensate for losses in the third space on the day of surgery or injury (only on this day), an additional amount of fluid should be added to the infusion therapy regimen - at least 40 ml/hour (1000 ml/day).
Losses in the gastrointestinal tract
Gastric fluid loss is easily accounted for with a properly placed nasogastric tube. Complete obstruction of the gastric outlet leads to a loss of more than 3 liters of fluid per day. If a nasogastric tube is not installed, then prolonged ileus leads to the accumulation of the same amount of fluid in the intestine. However, it is not possible to quantify losses, and the infusion therapy regimen must take into account early hidden losses. In subsequent days, these losses are best compensated for by adding fluid when symptoms of hypovolemia occur, as described below.
Bleeding (see also Chapter 6)
Lost blood is primarily replaced by transfusion of colloidal solutions. If the volume of losses can be measured (for example, in the suction reservoir), then it can serve as a guide when planning infusion and transfusion therapy. More often, lost blood remains within the body or its volume cannot be measured (for example, blood on swabs, drapes, surgical linens). The level of hemoglobin in the blood should be measured repeatedly so that red blood cell transfusions can be started in a timely manner. There are different opinions regarding what level of hemoglobin should be maintained during blood loss using blood transfusion. The author believes that it should be at least 100 g/l in case of concomitant diseases of the heart, lungs or cerebral ischemia and at least 80 g/l in the absence of these diseases. Hemodilution, which is carried out by administering colloidal solutions, reduces hemoglobin below the level at which it will later be established on its own, so it is quite safe to maintain a hemoglobin level of at least 80 g/l (in the absence of concomitant diseases).
In case of massive blood loss, transfusion of fresh frozen plasma, cryoprecipitate, platelet mass, antifibrinolytic agents, and other procoagulants may be required (Chapter 6). When conducting infusion-transfusion therapy, the volume of these drugs should be taken into account.
Polyuria
Some forms of kidney failure are characterized by very high urine output, which greatly increases fluid requirements. Diuresis up to 150 ml/h is regarded as a favorable sign after surgery, as it allows for more complete removal of protein breakdown products and medications.
Calculation of fluid requirements
The amount of fluid administered is often scheduled hourly, and it is much easier to calculate fluid requirements based on the patient's weight in kilograms. These hourly fluid administration calculations assume that the patient received adequate fluid resuscitation during surgery. If this was not the case, then it is first necessary to compensate for the previous fluid deficiency.
Fluid requirements are calculated as follows:
1. Physiological fluid requirement: 25 ml/kg/h - approximately 2000 ml/day.
2. Insensible losses: 20 ml/h - approximately 500 ml/day.
3. For fever: add 10 ml/h (250 ml/day) for each °C above 37 °C.
4. For suspected intestinal paresis: add 20 ml/hour (500 ml/day) - only in the first 24 hours after surgery.
5. For losses in the third space after laparotomy or thoracotomy: add 40 ml/hour (1000 ml/day) - only in the first 24 hours after surgery.
6. Compensate for any other measurable losses. See also table 26.
Table 26. Calculation of fluid requirements in the postoperative period for a man weighing 70 kg without concomitant diseases
Water... Without it, our life would be completely impossible. It seems that we know almost everything about water. But we don’t know even more. Here are some famous and unknown facts regarding water. Now many people say that you need to drink as much water as possible. However, in this matter you need to trust your own body and drink as much as it asks. Generally accepted standards for water consumption are relative and vary depending on a person’s age, gender, well-being, physical activity, availability various diseases and environmental conditions.
Some tips on this matter.
It is better to drink spring water. If you use tap water, it would be a good idea to either purify it, or boil it, or at least leave it for a few hours to remove the smell of bleach.
Babies under one year old who are on breastfeeding, thirst is quenched with mother's milk. Only in hot summers can they be given 20-30 ml of water between feedings
For 3-5 year old children, 300-400 ml is enough, for schoolchildren - 400-500 ml of water per day. An adult - on average 1.5-2 liters, but starting from 45-50 years old, this norm should be reduced to reduce the likelihood of edema
Men need more fluids because... they lose almost a liter more of it every day than women
It is better to drink water between meals, but it is not advisable to wash it down with food
A glass of water on an empty stomach is very beneficial for bowel function. You should drink 30-40 minutes before breakfast
You can drink a glass of warm water at night. This will help you calm down and will good remedy for insomnia
Caffeine and alcohol dehydrate the body, so try to drink a glass of water before drinking a cup of coffee or glass of wine.
Before a walk in the cold, it’s very good to drink a glass of water or hot tea, because... cold and dry air contributes to the loss of fluid by the body (remember the clouds of steam in the cold)
There are several calculation formulas daily consumption water. Here are some of them:
1. Two liters of liquid (or eight glasses) should be consumed by a person weighing 56 kg, and above that one glass should be added for every 20 kg of weight.
2. A person needs to drink 30-40 ml of water per 1 kg of weight.
3. For 1000 kilocalories received from food, you need to drink 1 liter of water.
4. According to many diets, you need to drink more water to dull the feeling of hunger. But here you need to be careful - you can get water intoxication. And unfortunately, the kilograms lost in this way are quickly gained
5. It is advisable to drink more during diarrhea, because its strong manifestation can cause sudden and rapid dehydration
6. The need for fluid also increases with more serious diseases. For example, doctors advise people prone to developing kidney stones to drink at least 2.5 liters of water per day to avoid relapses. A lot of fluids are also needed for urinary tract infections. However, in any case, it is better to consult your doctor, who will choose the right drinking regime, taking into account your illness and the effect of the medications you are taking.
Daily physical fluid requirement
cerebral edema (and its threat)– the total volume of liquid should not exceed 2/3 of the FP, while the IV part should not exceed ½ of the FP.
respiratory failure– at II degree. limit to ½ AF, with stage III DN. – 1/3 FP.
heart failure– maximum IV infusion is no more than ½ - 1/3 of AF, with hyposystole, complete cessation of IT.
renal failure– with the exception of prerenal acute renal failure V IV infusion not more than the sum of “imperceptible” losses (25 ml/kg/day in young children and 10 ml/kg/day in older children) and diuresis for the previous day
Clinical signs of dehydration
Clinical signs of dehydration (continued)
Infusion rate (drops/min)=
…..volume of liquid (ml)….
number of hours of infusionХ3
In shock behind first hour introduced 10-15ml/kg
For exicosis of I-II degree for the first 6-8 hours During rehydration, it is advisable to administer (along with food) a volume of fluid approximately equal to its original volume. extracellular volume deficiency:
Calcium FP=0.1-0.5 mmol/kg/day
(in newborns, premature infants 1-3 mmol/kg/day)
Ca chloride 10%=1 ml =1 mmol
Ca gluconate 10%=1 ml = 0.25 mmol
Enter 10% solution 0.5 ml/year/day (CaCl) -1 ml/year/day (Ca gluc.)
(no more than 10 ml), for 1-2 injections
Potassium FP = 1.0-2.0 mmol/kg/day
Potassium FP = 1.0-2.0 mmol/kg/day
The rate of K administration should not exceed 0.5 mmol/kg/hour!
Enter: - in glucose solution
- in the presence of diuresis
- divide the daily dose into 2 injections
- concentration of K in the solution is not more than 1%
7.5% solution = 1 ml = 1 mmol
4% solution = 1 ml = 0.5 mmol
Enter 7.5% solution 1-2 ml/kg/day
4% solution 2-4 ml/kg/day
Magnesium FP = 0.1-0.7 mmol/kg/day
Magnesium FP = 0.1-0.7 mmol/kg/day
25% = 1 ml = 2 mmol
We add glucose to the solution at the rate 0.5-1 ml/kg/day no more than 20 ml for 2 times
Sodium FP = 2 – 4 mmol/kg/day
10% NaCl=1 ml = 1.71 mmol
0.9% NaCl=10ml = 1.53 mmol
Soda
Soda
(correction of decompensated metabolic acidosis)
Volume of 4% soda (ml) = BE*weight/2
Divide the resulting volume by 2,
introduce it into the glucose solution 1:1, repeat the CBS
If there is no CBS, then enter 2 ml/kg
Do not administer soda if ventilation is impaired.
You cannot strive for complete and rapid compensation of acidosis; as soon as the pH reaches a level of 7.25 or more, the infusion is stopped and KCL is administered, since hypokalemia may occur due to the transition of K into the cell
Clinical
Clinical
Weight control 2 times a day
Hourly monitoring of diuresis
Normalization of hemodynamics (heart rate, blood pressure)
Laboratory
Biochemical parameters (Electrolytes, glucose, urea, creatinine, protein, acid-base balance, coagulogram)
UAC with Ht
OAM with specific gravity
Absolute amount of urine volume of liquid
Absolute amount of urine allocated for a certain time must be correlated with volume of liquid, introduced into the body during the same time interval.
It is necessary to maintain an accounting table
Hourly diuresis
If against the background of rehydration
If against the background of rehydration
Diuresis does not increase:
exclude surge arrester
it is possible that an excessive amount of saline solutions has been administered
Diuresis exceeds volume the resulting liquid
introduced excess solutions containing water (5% glucose)
because of excess concentrated solutions glucose, the patient developed osmotic diuresis
Principles of infusion rehydration therapy
General rules drawing up an infusion therapy program
1. Colloidal solutions contain sodium salts and belong to saline solutions and their volume must be taken into account in the total volume of saline solutions.
2. In total, colloidal solutions should not exceed 1/3 of the total daily volume of fluid for infusion therapy.
3. In young children, the ratio of glucose and salt solutions is 2:1 or 1:1; in older age, the amount of saline solutions increases (1:1 or 1:2).
3.1. The type of dehydration affects the ratio of glucose-saline solutions in the composition of infusion media.
4. All solutions must be divided into portions (“droppers”), the volume of which for glucose usually does not exceed 10-15 ml/kg and 7-10 ml for colloidal and saline solutions. The container for one drip should not contain more than ¼ of the daily volume of liquid. It is unrealistic to administer more than 3 drops per day to a child.
During infusion rehydration therapy, there are 4 stages: 1. anti-shock measures (1-3 hours); 2. Compensation for extracellular fluid deficiency (1-2-3 days); 3. maintaining water and electrolyte balance in conditions of ongoing pathological losses (2-4 days or more); parenteral nutrition (total or partial) or therapeutic enteral nutrition.
To maintain a state of homeostasis, it is necessary to ensure a balance between the fluid introduced into the body and the fluid that the body removes in the form of urine, sweat, feces, and exhaled air. The amount and nature of losses varies depending on the nature of the disease.
The amount of fluid required to compensate for the physiological losses of the body in children of different ages is not the same.
Table 1. 69.Age-specific fluid and electrolyte requirements for children
The physiological need for sodium in young children is 3-5 mmol/kg; in older children, 2-3 mmol/kg;
The potassium requirement is 1-3 mmol/kg;
The requirement for magnesium is on average 0.1 mmol/kg.
The fluid and electrolyte requirements needed to replace physiological losses can be calculated using several methods.
Daily maintenance fluid (fluid requirement) can be calculated in several ways: 1) based on body surface area (there is a correlation between these indicators); 2) energy method (there is a relationship between energy needs and body weight). The minimum water requirement is 100-150 ml/100 kcal; 3) according to the Aberdeen nomogram (or tables made on its basis - table 1.69).
For some pathological conditions losses of water and/or electrolytes may increase or decrease significantly.
Table 1.70.Current pathological losses. Conditions that change fluid requirements
| State | Fluid requirement |
| Fever Hypothermia Uncontrollable vomiting Diarrhea Heart failure Pulmonary edema Increased sweating Hyperventilation Increased air humidity Renal failure Intestinal paresis Phototherapy High ambient temperature Increased metabolism Mechanical ventilation of newborns (with good hydration) | Increase by 10 ml/kg for each degree of increase in temperature Decrease by 10 ml/kg for each degree of decrease in temperature Increase in requirement by 20-30 ml/kg/day Increase by 25-50 ml/kg/day Reduction in requirement by 25-50% depending on the degree of deficiency Reducing the need to 20-30 ml/kg/day Increasing the need by 10-25 ml/100 kcal Increasing the need to 50-60 ml/100 kcal Reducing the need by 0-15 ml/100 kcal Reducing the need to 15 -30 ml/kg/day Increase in need by 25-50 ml/kg/day Increase in need by 15-30% Increase in need by 50-100% Increase in need by 25-75% Reduction in need by 20-30 ml/kg of the daily requirement needs |
To cover the need for fluid, it is necessary to take into account the physiological need for fluid (1500-1800 ml/m 2) either calculated from tables (Table 1.69), or using the energy method and add to them the fluid losses identified in the patient.
General principles for calculating the required fluid:
SZh = SZhP+ ZhVO+ZhVTPP, Where SJ– calculated daily fluid, SZhP– daily maintenance fluid, ZHVO– fluid to compensate for dehydration, ZhVCCI- liquid to compensate for current pathological losses.
cerebral edema (and its threat)– the total volume of liquid should not exceed 2/3 of the FP, while the IV part should not exceed ½ of the FP.
respiratory failure– at II degree. limit to ½ AF, with stage III DN. – 1/3 FP.
heart failure– maximum IV infusion is no more than ½ - 1/3 of AF, with hyposystole, complete cessation of IT.
renal failure– with the exception of prerenal acute renal failure V IV infusion not more than the sum of “imperceptible” losses (25 ml/kg/day in young children and 10 ml/kg/day in older children) and diuresis for the previous day
Clinical signs of dehydration
Clinical signs of dehydration (continued)
Infusion rate (drops/min)=
…..volume of liquid (ml)….
number of hours of infusionХ3
In shock behind first hour introduced 10-15ml/kg
For exicosis of I-II degree for the first 6-8 hours During rehydration, it is advisable to administer (along with food) a volume of fluid approximately equal to its original volume. extracellular volume deficiency:
Calcium FP=0.1-0.5 mmol/kg/day
(in newborns, premature infants 1-3 mmol/kg/day)
Ca chloride 10%=1 ml =1 mmol
Ca gluconate 10%=1 ml = 0.25 mmol
Enter 10% solution 0.5 ml/year/day (CaCl) -1 ml/year/day (Ca gluc.)
(no more than 10 ml), for 1-2 injections
Potassium FP = 1.0-2.0 mmol/kg/day
Potassium FP = 1.0-2.0 mmol/kg/day
The rate of K administration should not exceed 0.5 mmol/kg/hour!
Enter: - in glucose solution
- in the presence of diuresis
- divide the daily dose into 2 injections
- concentration of K in the solution is not more than 1%
7.5% solution = 1 ml = 1 mmol
4% solution = 1 ml = 0.5 mmol
Enter 7.5% solution 1-2 ml/kg/day
4% solution 2-4 ml/kg/day
Magnesium FP = 0.1-0.7 mmol/kg/day
Magnesium FP = 0.1-0.7 mmol/kg/day
25% = 1 ml = 2 mmol
We add glucose to the solution at the rate 0.5-1 ml/kg/day no more than 20 ml for 2 times
Sodium FP = 2 – 4 mmol/kg/day
10% NaCl=1 ml = 1.71 mmol
0.9% NaCl=10ml = 1.53 mmol
Soda
Soda
(correction of decompensated metabolic acidosis)
Volume of 4% soda (ml) = BE*weight/2
Divide the resulting volume by 2,
introduce it into the glucose solution 1:1, repeat the CBS
If there is no CBS, then enter 2 ml/kg
Do not administer soda if ventilation is impaired.
You cannot strive for complete and rapid compensation of acidosis; as soon as the pH reaches a level of 7.25 or more, the infusion is stopped and KCL is administered, since hypokalemia may occur due to the transition of K into the cell
Clinical
Clinical
Weight control 2 times a day
Hourly monitoring of diuresis
Normalization of hemodynamics (heart rate, blood pressure)
Laboratory
Biochemical parameters (Electrolytes, glucose, urea, creatinine, protein, acid-base balance, coagulogram)
UAC with Ht
OAM with specific gravity
Absolute amount of urine volume of liquid
Absolute amount of urine allocated for a certain time must be correlated with volume of liquid, introduced into the body during the same time interval.
It is necessary to maintain an accounting table
Hourly diuresis
If against the background of rehydration
If against the background of rehydration
Diuresis does not increase:
exclude surge arrester
it is possible that an excessive amount of saline solutions has been administered
Diuresis exceeds volume the resulting liquid
introduced excess solutions containing water (5% glucose)
because of excess concentrated solutions glucose, the patient developed osmotic diuresis
There are many approaches for rehydration; most of them are interchangeable, based on the same principles, and the superiority of any one of them has not been proven. For practical reasons, the calculations are based on the weight upon admission, and not the value of the proper weight. The first step is to achieve hemodynamic stability; this ensures the maintenance of cerebral and renal blood flow and the inclusion of compensatory mechanisms aimed at restoring BCC.
The first stage of therapy consists of a rapid infusion of a relatively isotonic fluid (saline or lactated Ringer's solution). If dehydration plays a major role (for example, with pyloric stenosis), lactated Ringer's solution is not used, since lactate aggravates metabolic alkalosis caused by the loss of acidic gastric contents. Most oral rehydration solutions contain buffers, which also contribute to the increase in metabolic alkalosis in young children with profuse vomiting. For mild to moderate dehydration, infusion is carried out over 1-2 hours at a rate of 10-20 ml/kg (1-2% of weight).
In case of severe dehydration, infusion is carried out at a rate of 30-50 ml/kg/h until stable hemodynamics are restored. The initial rapid infusion of isotonic fluid has several goals:
1) gain time until test results are received;
2) prevent further dehydration;
3) concentrate on creating a rehydration program.
The volume of liquid introduced at this stage is not taken into account in further calculations.
On second stage losses of fluid and electrolytes are compensated before the child is admitted to the hospital. Many approaches to rehydration are based on the same principles.
1. With all types of rehydration, replenishment of losses is carried out slowly.
2. Potassium losses should not be quickly replaced. Potassium is predominantly an intracellular ion, and therefore even rapid administration of its concentrated solutions will not have the desired effect, but can cause deadly complications. Potassium is added only after urinating twice at a concentration of no more than 40 mEq/L or at an infusion rate of 0.5 mEq/kg/h.
3. To replenish the deficiency of water and NaCl, a 0.45% NaCl solution containing 77 meq/L Na+ and Cl- is best suited. It contains more sodium than standard maintenance solutions, but the water to sodium ratio is higher than plasma.
Above are two example programs replenishment infusion therapy. In program I, maintenance therapy is not added to replenishment therapy. The infusion rate is calculated in such a way as to completely replenish the expected deficiency within 6-8 hours. The main attention is paid to replenishing the deficiency, and the remaining components of infusion therapy are left for later.
In some cases, rapid administration of a large volume is implied, which limits the use of this program in adolescents, patients with diabetic ketoacidosis, infants with hypertensive dehydration, and children with dehydration greater than 10%. In such cases, as well as in older children, program II is preferable - slow and long-term replenishment of fluid deficiency. In this case, replenishing therapy is complemented by supportive therapy. The calculations in this case are more complicated than for program I. The infusion rate is the sum of the rate required for maintenance therapy and the rate that ensures the elimination of half of the fluid deficit within 8 hours.
For children weighing up to 10 kg, the infusion volume is approximately the same in both programs. So, a child weighing 10 kg with a degree of dehydration of 10% will have a fluid deficit of 1000 ml. In accordance with program I, replenishment of such a deficit in 8 hours is possible with an infusion rate of 125 ml/h. In the case of program II, half of the deficit (500 ml) is compensated in 8 hours, that is, the rate of replenishment infusion is 62.5 ml/h; the maintenance infusion rate is 40 ml/h. Thus, the total infusion rate is 102 ml/hour. Both of these programs are possible with isotonic or hypotonic dehydration, but not with hypertonic dehydration.
Treatment of hypertensive dehydration- this is very special and difficult task, requiring a thorough assessment of the condition and a different approach to the rate of restoration of fluid deficiency. In such children, it is easy to underestimate the severity of dehydration based on the clinical picture. Sodium losses are less than with other types of dehydration, so it would seem that the sodium content in the administered solutions should be reduced.
However, rapid administration of hypotonic solutions entails the movement of water into dehydrated cells with hypertonic cytoplasm, which can lead to cerebral edema. In this regard, in case of hypertensive dehydration, the infusion rate should be calculated with particular care. You can use 0.18% NaCl with 5% glucose or 0.45% NaCl with 5% glucose. The deficiency should be replenished within 24-48 hours simultaneously with maintenance infusion therapy. The infusion rate is adjusted so that the serum sodium concentration decreases by 0.5 mEq/L/h, or by 12 mEq/L/day. Hypertensive dehydration may be complicated by hypocalcemia (rarely) or hyperglycemia.
If there are clinical manifestations of hypocalcemia, calcium gluconate is administered intravenously under monitoring. Hyperglycemia occurs due to decreased insulin secretion and decreased cellular sensitivity to insulin. It is important to remember that against the background of hyperglycemia, measuring serum Na+ concentration gives an underestimated result: every 100 mg% increase in glucose concentration above the 100 mg% level decreases the Na+ concentration by 1.6 mEq/L. For example, with a measured sodium concentration of 178 mEq/L and a glucose concentration of 600 mg%, the actual sodium concentration is 170 mEq/L (600 - 100 = 500; 500 x x 1.6/100 = 8).
For all types of dehydration second stage of replenishment infusion therapy requires careful monitoring. Since the initial degree of dehydration is determined by subjective criteria, it is extremely important to constantly assess the adequacy of fluid therapy by changes in clinical parameters. So, if upon admission there is an increased specific gravity of urine (1.020-1.030), then with properly selected infusion therapy, the frequency of urination should increase, and the specific gravity of urine should decrease. Infusion parameters (rate, volume, duration) are calculated in advance, but constant adjustment is necessary based on changes in the clinical picture.
If tachycardia and other signs of dehydration persist, either the severity of dehydration has been underestimated or ongoing fluid losses are greater than expected. In this case, the infusion rate should be increased or an additional rapid infusion should be performed. Signs of improvement are considered to be an increase in diuresis, a decrease in the specific gravity of urine, and restoration of blood volume. If the condition improves quickly, the second stage of replenishment therapy can be shortened and the patient can be transferred to maintenance therapy.
After surgery, any adult patient weighing more than 60 kg with normal kidney function should receive at least 2000 ml of fluid per day. After major surgery, most fluids are given intravenously, and the volume may be larger. In the absence of underlying renal or cardiac disease, the goal of the infusion is to provide a safe fluid load that allows homeostatic mechanisms to self-distribute fluid and remove excess fluid. The required volume of infusion is calculated by determining the physiological need for fluid and taking into account additional existing and current losses.
With normal renal function, the target is urine output of 1 ml/kg/h. Diuresis determines the physiological need for fluid. With a weight of 80 kg, diuresis should be 80 ml/h. To draw up an infusion therapy plan, it is more convenient to assume that there are 25 hours in a day. This means that this patient will need 25x80 = 2000 ml of fluid per day. In this case, it is better to be a little generous and round up the values. To finally determine the volume of daily infusion, it is necessary to take into account a number of the following factors.
Fever and intangible losses
Intangible fluid loss through the skin and lungs is called; Normally, the volume of these losses is about 50 ml/h (1200 ml/day). During the metabolism of nutrients in the body, on the contrary, water is formed; its volume is usually subtracted from intangible losses. As a result, it turns out that the volume of imperceptible losses is about 20 ml/hour (500 ml/day). With fever and high ambient temperatures, the intensity of both processes increases. As a result, the increase in intangible losses (minus the water formed during metabolism) is 250 ml/day for each °C above 37 °C.
Losses in the "third space"
In the area of massive tissue damage, edema forms (Chapter 1). This fluid accumulated in the intersticial space does not exchange with other fluid spaces of the body. This anatomically non-existent space was called the “third” (in addition to the two real ones - extra- and intracellular). A lot of fluid can accumulate in the third space after laparotomy and thoracotomy, as well as with massive soft tissue damage. To compensate for losses in the third space on the day of surgery or injury (only on this day), an additional amount of fluid should be added to the infusion therapy regimen - at least 40 ml/hour (1000 ml/day).
Losses in the gastrointestinal tract
Gastric fluid loss is easily accounted for with a properly placed nasogastric tube. Complete obstruction of the gastric outlet leads to a loss of more than 3 liters of fluid per day. If a nasogastric tube is not installed, then prolonged ileus leads to the accumulation of the same amount of fluid in the intestine. However, it is not possible to quantify losses, and the infusion therapy regimen must take into account early hidden losses. In subsequent days, these losses are best compensated for by adding fluid when symptoms of hypovolemia occur, as described below.
Bleeding (see also Chapter 6)
Lost blood is primarily replaced by transfusion of colloidal solutions. If the volume of losses can be measured (for example, in the suction reservoir), then it can serve as a guide when planning infusion and transfusion therapy. More often, lost blood remains within the body or its volume cannot be measured (for example, blood on swabs, drapes, surgical linens). The level of hemoglobin in the blood should be measured repeatedly so that red blood cell transfusions can be started in a timely manner. There are different opinions regarding what level of hemoglobin should be maintained during blood loss using blood transfusion. The author believes that it should be at least 100 g/l in case of concomitant diseases of the heart, lungs or cerebral ischemia and at least 80 g/l in the absence of these diseases. Hemodilution, which is carried out by administering colloidal solutions, reduces hemoglobin below the level at which it will later be established on its own, so it is quite safe to maintain a hemoglobin level of at least 80 g/l (in the absence of concomitant diseases).
In case of massive blood loss, transfusion of fresh frozen plasma, cryoprecipitate, platelet mass, antifibrinolytic agents, and other procoagulants may be required (Chapter 6). When conducting infusion-transfusion therapy, the volume of these drugs should be taken into account.
Polyuria
Some forms of kidney failure are characterized by very high urine output, which greatly increases fluid requirements. Diuresis up to 150 ml/h is regarded as a favorable sign after surgery, as it allows for more complete removal of protein breakdown products and medications.
Calculation of fluid requirements
The amount of fluid administered is often scheduled hourly, and it is much easier to calculate fluid requirements based on the patient's weight in kilograms. These hourly fluid administration calculations assume that the patient received adequate fluid resuscitation during surgery. If this was not the case, then it is first necessary to compensate for the previous fluid deficiency.
Fluid requirements are calculated as follows:
1. Physiological fluid requirement: 25 ml/kg/h - approximately 2000 ml/day.
2. Insensible losses: 20 ml/h - approximately 500 ml/day.
3. For fever: add 10 ml/h (250 ml/day) for each °C above 37 °C.
4. For suspected intestinal paresis: add 20 ml/hour (500 ml/day) - only in the first 24 hours after surgery.
5. For losses in the third space after laparotomy or thoracotomy: add 40 ml/hour (1000 ml/day) - only in the first 24 hours after surgery.
6. Compensate for any other measurable losses. See also table 26.
Table 26. Calculation of fluid requirements in the postoperative period for a man weighing 70 kg without concomitant diseases
Potassium chloride is added to the glucose solution (evenly diluted in it!) (1...1.5 ml of a 7.5% solution for every 100 ml of glucose solution). In 8…12 hours, the child should receive a volume of liquid equal to the daily water requirement. For grade III severity and all complicated acute poisonings, diuretics are prescribed in addition to the water load. In these situations, forcing diuresis is carried out in 2 stages.
At stage I, it is necessary to determine whether the patient has hidden renal failure. The fluid is infused into the central (subclavian or jugular) veins; V bladder An indwelling catheter is inserted to record the amount of urine output. Within an hour (from the start of treatment), hemodez or rheopolyglucin - 20 ml/kg and 4% sodium bicarbonate solution are infused intravenously.
At the same time, the amount of urine excreted, its density and, if possible, the sodium concentration in the urine are recorded.
If a pre-uric phase of renal failure is detected in a child, then forced diuresis cannot be carried out further! If there is no renal failure, then proceed to the next stage of forced diuresis. Osmotic - mannitol, sorbitol or loop - furosemide - diuretics are administered.
“Pediatrician’s Handbook of Clinical Pharmacology”, V.A. Gusel
Milk can be used to lavage the stomach, but it cannot be considered as an antidote: it contains fats and, if left in the stomach, promotes the absorption of fat-soluble poisons; it neutralizes the acidity of gastric juice, thereby accelerating the opening of the pyloric sphincter, the entry of poison into the intestines and its absorption. The proteins contained in milk only temporarily bind the poison, but after digestion they release it...
Amyl nitrite also forms methemoglobin, which is why it is also used for cyanide and hydrogen sulfide poisoning, but only in children over 5 years of age. 1-2 drops of the drug are applied to a cotton ball and allowed to inhale. The child should lie down, as nitrite causes vasodilation, and arterial and venous pressure may drop. Inhalation of the drug while standing may lead to...
For all poisonings Activated carbon should be prescribed after rinsing. It should be noted that different poisons are sorbed by coal to varying degrees. Sorbed substance Sorption value % Sorbed substance Sorption value % Acetylsalicylic acid 90 Quinidine 44 Phenamine 94 Propylthiouracil 33 Colchicine 94 Quinine 32 Diphenine 90 Meprotane 25 Ergotamine 92 Paracetamol 23 Phenobarbital 86 Paracetamol 15...
Elimination of breathing disorders. When breathing stops, first of all, it is necessary to remove the contents from the mouth and pharynx (perhaps the contents of the stomach entered through regurgitation). Then sequentially carry out: artificial pulmonary ventilation (ALV) mouth to mouth or using a bag through a mask; oxygen therapy; tracheal intubation; Mechanical ventilation - through an anesthesia machine - with a gas mixture containing 40% oxygen (at ...
Some substances may desorb, freeing themselves from the surface of the coal. Therefore, after taking charcoal, it is necessary to accelerate intestinal motility and evacuation of its contents. Age of the child's water Amount of water for a cleansing enema, ml Total amount for a siphon enema, ml 1...2 months 30...40 - 2...4 months 60 800...1000 6...9 months 100...120 100O...1500 9...12 months 200 1500 2 …5…
The method of administering fluid depends on the severity of the child’s condition. Not the entire calculated volume of daily fluid requirements is administered parenterally; the other part of the fluid is given per os.
At I degree exicosis, oral rehydration and, if necessary, infusion therapy in a volume of no more than 1/3 of the patient’s daily fluid requirements are used. The need for IT arises if it is not possible to feed the child, and signs of toxicosis with exicosis increase.
At II degree exicosis is indicated for IT in an amount of no more than 1/2 depending on the patient’s daily fluid needs. The amount of liquid missing from daily requirements is given per os.
At IIIdegrees exicosis is indicated for IT in a volume of no more than 2/3 of the patient’s daily fluid requirements.
Types of solutions
The following types of solutions are used for infusion therapy:
« Aqueous solutions - 5% and 10% glucose. 5% The glucose solution is isotonic, quickly leaves the vascular bed and enters the cell, therefore its use is indicated for intracellular dehydration. A 10% glucose solution is hyperosmolar, due to which it has a volemic effect, in addition, it has a detoxification effect. The use of 10% glucose requires the addition of insulin at the rate of 1 unit per 50 ml of 10% glucose. ^ y
Crystalloids, saline solutions - Ringer's solution, disol, trteol, quadrasol, lactosol, saline. They quickly leave the vascular bed, moving into the interstitial space, which can cause edema in children in the first months of life who have an unstable Na* balance. younger child, the smaller the volume of saline solutions is introduced, which is reflected in the table. 3. For children in the first months of life, saline solutions are administered in a volume of no more than 1/3 of the volume of IT. Single dosage no more than 10 ml/kg per day.
In practice, Ringer-Locke solution is often used; it contains 9 g of sodium chloride, 0.2 g of calcium chloride, potassium chloride, sodium bicarbonate, 1 g of glucose, and water for injection up to 1 liter. This solution is more physiological than isotonic sodium chloride solution.
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Colloidal solutions medium molecular weight - infucol, reopolyglucin,
reogluman, reomacrodex, rondex, volecam, plasma, gelatinol, 10%
albumen. L ^/Н^сР y £ -
/(/ g V,
Low molecular weight (hemodez, polydes) and high molecular weight (polyUlyukin)
Colloids are used very rarely for exicosis in children.
Colloidal solutions usually make up no more than 1/3 of the total volume of IT.
It is recommended to use infucol HES, a 2nd generation hydroxyethylstarch preparation. It causes the transition of fluid from the interstitial space to the intravascular space, binds and retains water in the bloodstream, thereby ensuring a long-term volemic effect (up to 6 hours). Has no age restrictions. Available in the form of 6% and 10% solutions.
A 6% solution is prescribed at a dose of 10-20 ml/kg per day, up to a maximum of 33 ml/kg.
A 10% solution is prescribed at a dose of 8-15 ml/kg per day, up to a maximum of 20 ml/kg.
Among the new drugs, reamberin should be noted. It has detoxification, antihypoxic effects, and has a slight diuretic effect. Available as a 1.5% solution in bottles of 200 and 400 ml. It is administered to children at a dose of 10 ml/kg intravenously at a rate of no more than 60 drops per minute, once a day, for a course of 2-10 days.
Solutions for parenteral nutrition - infezol, lipofundin, intralipid, alvesin, aminon. They are rarely used for exicosis in children.
Table 3
The ratio of aqueous and colloidal-saline solutions used for infusion therapy, depending on the type of exicosis.
Example. When calculating using the first method, the patient’s daily fluid requirements are 9 months. equal to 1760 ml. With exicosis of the second degree, the volume of IT will be 1/2 of this amount, i.e. 880 ml. We will give the remaining 880 ml to the child per os in the form of rehydron, raisin decoction, kefir. Let’s say that, according to the conditions of the problem, the child has an isotonic type of exicosis. We choose the ratio of aqueous and colloidal-saline solutions 1:1, then from 880 ml we take 440 ml of 5% glucose
(aqueous solution), 280 ml of rheopolyglucin (colloid - no more than 1/3 of the total volume of IT) and 160 ml of Ringer's solution (saline solution).
When carrying out IT, the injected solutions are divided into portions volume 100-150 ml depending on the age of the patient. The younger the child, the smaller the volume of a single serving.
During IT, you should alternate portions of aqueous and colloidal saline solutions - this is the “layer cake” rule.
Selecting a starting solution
Determined by the type of dehydration. In water-deficient exicosis, 5% glucose is administered first; in other types of exicosis, IT most often begins with a colloidal solution, sometimes with saline.
Example. 440 ml of 5% glucose can be divided into 4 servings (14i, 100,100 ^ and 100 ml); 280 ml of rheopolyglucin - for 2 servings of 140 ml; 160 ml of Ringer's solution - for 2 servings of 80 ml. The starting solution is rheopolyglucin.
serving - reopolyglucin 140 ml
serving - 5% glucose 140 ml
serving - 5% glucose 100 ml
serving - rheopolyglucin 140 ml
serving - 5% glucose 100 ml
portion - Ringer's solution 80 ml
serving - 5% glucose 100 ml
Using corrector solutions
In infusion therapy, corrector solutions are used, which include, first of all, various electrolyte supplements. With IT, the child’s daily physiological needs for them must be provided, and the identified deficiency must be compensated (Table 4).
Typical clinical manifestations hypokalemia are weakness of the muscles of the limbs and trunk, weakness of the respiratory muscles, areflexia, bloating, intestinal paresis. Hypokalemia helps to reduce the concentrating ability of the kidneys, resulting in the development of polyuria and polydipsia. The ECG shows a decrease in the voltage of the T wave, a U wave is recorded, the S-T segment moves below the isoline, and the Q-T interval lengthens. Severe hypokalemia leads to expansion of the QRS complex, the development of various types of heart rhythm disturbances, atrial fibrillation, and cardiac arrest in systole.
The K+ requirements of young children are 2-3 mmol/kg per day, over 3 years old - 1-2 mmol/kg per day. In practice, a 7.5% solution of KS1 is used, 1 ml of which contains 1 mmol K+, less often 4% KS1, the K+ content of which is approximately 2 times less.
Rules for administering K+ solutions:
they must be administered in a concentration of no more than 1%, i.e. A 7.5% solution of KS1 should be diluted approximately 8 times;
jet and rapid drip administration of potassium solutions is strictly prohibited, as it can cause hyperkalemia and cardiac arrest. It is recommended to administer potassium solutions intravenously slowly at a rate of no more than 30 drops/min, i.e. no more than 0.5 mmol/kg per hour;
administration of K+ is contraindicated for oliguria and anuria;
Example calculating the introduction of K+. If the child weighs 8 kg daily requirement in K+ is 2 mmol/kg x 8 kg = 16 mmol, which is 16 ml of a 7.5% solution of KS1. You can divide these 16 ml into 4 parts of 4 ml and add to IT portions containing 5% glucose.
K+def. = (K+normal - K+patient) x 2t.
where m is mass in kg,
K - coefficient, which for newborns is 2, for children under 1 year - 3,
for children 2-3 years old - 4, over 5 years old - 5.
In isotonic and salt-deficient exicosis, K+ deficiency can be calculated by the hematocrit value:
K+def. = Htnorm -Htsick x sch/5,
YuO-Ht norm
where Ht norm is hematocrit healthy child corresponding age (%). In newborns this is an average of 55%, at 1-2 months. - 45%, at 3 months. - 3 years - 35% (see appendix).
Expressed hypocalcemia manifested by disturbances in neuromuscular excitability, cardiac activity and convulsions.
Ca+ requirements average 0.5 mmol/kg per day. In practice, a 10% calcium chloride solution is used, 1 ml of which contains 1 mmol Ca+, or a 10% solution of calcium gluconate, 1 ml of which contains 0.25 mmol Ca+. Calcium gluconate can be administered intravenously or intramuscularly, calcium chloride - only intravenously (!).
Example calculating the introduction of Ca+. If a child weighs 8 kg, his daily requirement for Ca+ is 0.5 mmol/kg x 8 kg = 4 mmol, which is 16 ml
10% calcium gluconate solution. You can divide these 16 ml into 4 parts of 4 ml and add to IT portions containing 5% glucose.
Needs forMg+ are 0.2-0.4 mmol/kg per day. A 25% solution of magnesium sulfate is used, 1 ml of which contains 1 mmol Mg+.
Example calculating the introduction of Mg+. If a child weighs 8 kg, his daily requirement is Mg+ is 0.2 mmol/kg x 8 kg = 1.6 mmol, which is 1.6 ml of a 25% magnesium sulfate solution. You can divide 1.6 ml into 2 parts according to
8 ml and add to 2 and 6 servings of IT containing 5% glucose.
Correction of sodium and chlorine is not carried out additionally, because all intravenous solutions contain these electrolytes.
Distribution of administered solutions during the day
The following treatment periods are distinguished:
emergency rehydration phase - the first 1-2 hours;
final elimination of the existing deficiency of water and electrolytes - 3-24 hours;
supportive detoxification therapy with correction of ongoing pathological losses.
In case of compensated exicosis, infusion solutions are administered over approximately 2-6 hours, in case of decompensated exicosis - over 6-8 hours.
Fluid injection rate determined by the severity of dehydration and the age of the patient.
In severe cases, forced fluid administration is used in the first 2-4 hours of IT, then slow, with an even distribution of the entire volume of fluid throughout the day. In case of hypovolemic shock, the first 100-150 ml of solution is administered slowly in a stream.
Injection rate = V / 3t,
where V is the volume of IT, expressed in ml,
t - time in hours, but not more than 20 hours per day.
The rate of fluid administration calculated in this way is expressed in drops/min, in the absence of a correction factor of 3 in the formula - in ml/hour.
Table 5
Approximate rate of fluid administration during infusion therapy, drops/min.
|
Introduction liquids | ||||
|
newborn | ||||
|
Forced | ||||
|
Slow | ||||
It is safe to administer up to 80-100 ml/hour for children under 3 months. - up to 50 ml/hour (10 drops/min).
IT in newborns requires special care and careful monitoring. The rate of intravenous fluid administration in case of exicosis of the first degree is usually 6-7 drops/min (30-40 ml/hour), in case of exicosis of the second degree
8-10 drops/min (40-50 ml/hour), III degree - 9-10 drops/min (50-60 ml/hour).
1 ml of aqueous solutions contains 20 drops, which means that an injection rate of 10 drops/min will correspond to 0.5 ml/min or 30 ml/hour; 20 drops/min - 60 ml/hour. Colloidal solutions are introduced at a rate approximately 1.5 times slower than aqueous ones.
IT Adequacy Assessment should be based on the dynamics of symptoms of dehydration, the condition of the skin and mucous membranes (moisture, color), the function of the cardiovascular system and other clinical manifestations of exicosis. Monitoring is also carried out by control weighings (every 6-8 hours), measuring pulse, blood pressure, central venous pressure (normally 2-8 cm water column or
196 - 0.784 kPa), average hourly diuresis, relative density of urine (the norm here is 1010-1015), hematocrit.
The adequacy of the qualitative composition of solutions for IT is monitored by indicators of acid-base status, concentration of electrolytes in blood plasma and urine.
