I. Overview

1. Composition and distribution of body fluids. Adult male body fluids account for about 60% of body weight; Women account for about 50%; Babies can be as high as 70% ~ 80%. Body fluid consists of intracellular fluid and extracellular fluid. The extracellular fluid of men and women accounts for about 20% of body weight.

2. Body fluid balance and regulation

(1) water balance: the stability of human internal environment depends on the constant water content in the body. The human body takes in a certain amount of water every day, and at the same time discharges a corresponding amount of water, so as to achieve the dynamic balance of water in and out every day.

Daily intake of normal adults (ml): drinking water 1600ml, food 700ml, metabolic oxidation raw water 200ml, a total of 2500ml；; Normal adult daily output (ml): urine 1500ml, feces 200ml, exhalation 300ml, skin evaporation 500ml, totaling 2500ml.

(2) Electrolyte balance: Na+ and K+ are the main electrolytes to maintain the electrolyte balance of body fluids.

(3) Adjustment of body fluid balance: The stability of body fluid volume and osmotic pressure is regulated by neuroendocrine system.

3. Acid-base balance and regulation The human body mainly relies on buffer pairs, lungs and kidneys in body fluids to regulate acid-base balance. HCO3/H2CO3 is the most important buffer system, and its ratio is kept at 20: 1.

Second, water and sodium metabolism disorder

(1) Etiological classification and clinical manifestations

1. Isoosmotic water shortage refers to the proportional loss of water and sodium. This is the most common type of water shortage. Common reasons are:

(1) Acute loss of digestive juice, such as massive vomiting, intestinal fistula, intestinal obstruction, etc.

(2) Acute loss of body fluids, such as acute peritonitis and early extensive burns.

2. Hypoosmotic water shortage means that water and sodium are lost at the same time, but sodium loss is more than water loss, and serum sodium is lower than135 mmol/L. Common reasons are:

(1) The continuous loss of digestive juice in gastrointestinal tract leads to excessive sodium loss, such as repeated vomiting, diarrhea or chronic exudation from large wounds.

(2) Patients with isotonic fluid loss only drink boiled water, or intravenous infusion of a large amount of glucose solution, resulting in the dilution of extracellular fluid.

(3) Long-term use of sodium diuretics.

3. Hypertonic water deficiency means that water and sodium are lost at the same time, but water loss is more than sodium loss, and serum sodium is higher than150 mmol/L. Common reasons are:

(1) Insufficient water intake, such as long-term fasting, dysphagia, coma without rehydration, or nasal feeding with high-concentration enteral nutrition solution.

(2) Excessive water loss, such as evaporation of a large amount of water from large burn wounds, sweating due to high fever, hyperosmotic diuresis caused by uncontrolled blood sugar in diabetic patients, etc.

4. The total inflow of water poisoning exceeds the discharge, and water poisoning is rare. Common reasons are:

(1) Decreased urination ability in renal failure.

(2) Excessive water intake or intravenous infusion.

(3) Excessive ADH secretion is caused by various reasons.

(2) Clinical manifestations

1. Patients with isotonic water shortage have symptoms such as nausea, vomiting, anorexia, dry mouth, sunken eye sockets, decreased skin elasticity and oliguria, but they are not thirsty. When the loss of body fluids reaches 5% of body weight in a short time, it can be manifested as shock symptoms such as increased heart rate, weakened pulse, unstable or decreased blood pressure, and cold limbs, often accompanied by metabolic acidosis.

2. Patients with hypotonic water shortage have no obvious thirst, but appear obvious fatigue, dizziness, fatigue, nausea and vomiting, apathy and gastrocnemius spasm pain due to sodium deficiency; Standing syncope, blood pressure drop and even shock occurred earlier. Early urine volume is normal or slightly increased, but the specific gravity of urine is low, and the contents of sodium and chlorine in urine are reduced; There is less urine in the later stage, but the proportion of urine is still low.

3. Hypertonic water shortage

(1) Mild: Water deficit accounts for 2% ~ 4% of body weight. No other clinical symptoms except thirst.

(2) Moderate: Water deficit accounts for 4% ~ 6% of body weight. In addition to extreme thirst, it is often accompanied by irritability, fatigue, poor skin elasticity, sunken eye sockets, oliguria and increased urine proportion.

(3) Severity: Water deficit is greater than 6% of body weight. In addition to the above symptoms, there may be brain dysfunction such as mania, hallucination, delirium and even coma.

4. Water poisoning

(1) Acute water poisoning starts with acute onset, especially brain edema, characterized by headache, vomiting, blurred vision, delirium, convulsion and even coma, and in severe cases, brain hernia may occur.

(2) Chronic water poisoning is mostly covered by the symptoms of primary disease, and symptoms such as fatigue, nausea, vomiting, lethargy, weight gain and pale skin may appear.

(3) Auxiliary inspection

1. Laboratory tests showed that the red blood cell count, hemoglobin and hematocrit all increased in different degrees. It all went down during water poisoning.

2. Serum electrolyte test showed that the serum sodium was 65438 0.50 mmol/L. In case of water poisoning, the serum sodium could be reduced to below 65438 0.20 mmol/L.

3. Arterial blood gas analysis can simultaneously judge whether there is acid (alkali) poisoning.

(4) The principle of treatment is to eliminate the cause as soon as possible and then deal with it accordingly.

1. Isotonic water shortage can generally supplement isotonic saline or balanced salt solution.

2. Patients with hypotonic water deficiency and mild to moderate sodium deficiency are generally supplemented with 5% glucose salt solution; Intravenous drip of hypertonic saline in patients with severe sodium deficiency.

3. Hypertonic water shortage should encourage patients to drink water and add 5% glucose solution intravenously, and supplement sodium appropriately when necessary.

4. Patients with mild water poisoning only need to limit the amount of drinking water. In severe cases, hypertonic saline should be infused intravenously to relieve cell swelling and hypotonic state, and osmotic diuretics should be used as appropriate.

(5) Nursing problems

1. Deficiency of body fluid is related to high fever, vomiting, diarrhea and gastrointestinal decompression leading to massive loss of body fluid.

2. Excessive body fluids are related to excessive intake and excretion.

3. The risk of skin integrity damage is related to edema and insufficient microcirculation perfusion.

(6) Nursing measures

1. Maintain adequate body fluid volume.

(1) Eliminate the cause.

(2) Implement liquid therapy: The principles of quantification, qualitative and timing should be strictly followed when rehydrating.

1) quantification: including physiological requirement, loss and continuous loss.

2) Qualitative analysis: according to the types of body fluid imbalance, select the types of supplementary liquids, such as electrolyte, non-electrolyte, colloid, alkaline solution, etc.

3) Timing: The fluid infusion per unit time depends on the amount and speed of body fluid loss and the functional state of various organs, and should be distributed according to the principle of fast first and slow later, that is, 65,438+0/2 of the total fluid infusion in the first 8 hours, and 65,438+0/2 of the rest should be evenly input in the next 65,438+06 hours.

(3) Accurately record the 24-hour water inflow and outflow, and timely adjust the rehydration scheme.

(4) Observation of curative effect: In the process of fluid replacement, nurses must closely observe the therapeutic effect and pay attention to adverse reactions.

2. Patients with excessive body fluid poisoning should strictly control the amount of drinking water, and patients with severe water poisoning should be given hypertonic solution (such as 3% sodium chloride solution) and diuretics, such as furosemide. At the same time, pay attention to the dynamic changes of illness and urine volume. Dialysis nursing according to doctor's advice.

3. Maintain the integrity of the skin and mucosa, strengthen the observation of the disease, do a good job in preventing pressure ulcers, guide patients to develop good hygiene habits, and often clean their mouths with mouthwash; Patients with severe oral mucosal inflammation should be given oral care every 2 hours and take medicine according to the doctor's advice.

(7) Health education

1. Establish an appropriate and safe activity mode. Nurses should work out the time, amount and mode of activities together with patients and their families to avoid disuse muscular atrophy caused by long-term bed rest.

2. Operators in high temperature environment and personnel engaged in high-intensity sports activities should replenish water and drink salt in time.

Drinks

3. Eating difficulties, vomiting, diarrhea, bleeding, etc. It is easy to cause imbalance of body fluids, so you should seek medical treatment as soon as possible.

Third, abnormal potassium metabolism.

(1) etiology

1. Hypokalemia serum potassium

(1) Insufficient intake, such as long-term fasting, eating less or insufficient intravenous potassium supplementation.

(2) The loss of body fluids increases, and diuretics are used to promote excretion.

(3)K+ is transported into cells, such as a large number of hypertonic glucose and insulin, metabolic alkalosis, etc.

2. Hyperkalemia > serum potassium; 5.5 mmol/L. Common reasons are:

(1) potassium excretion disorder: it is more common in renal failure and is a common cause of hyperkalemia.

(2) Abnormal distribution in the body: hypoxia and acidosis, cells release a large amount of potassium, which leads to high serum potassium.

(3) Excessive intake: too much, too fast, too concentrated intravenous potassium, and a large number of long-term preserved blood transfusion.

(2) Clinical manifestations

1. Hypokalemia

(1) Myasthenia: It is the earliest clinical manifestation, and generally myasthenia of limbs occurs first.

(2) Dysfunction of digestive tract: nausea, vomiting, abdominal distension and intestinal paralysis.

(3) Abnormal cardiac function: manifested as tachycardia, decreased blood pressure, ventricular fibrillation and cardiac arrest.

(4) Metabolic stilbene poisoning and contradictory aciduria.

2. Hyperkalemia is characterized by apathy, fatigue, quadriplegia, abdominal distension and diarrhea. In severe cases, there are manifestations of microcirculation disturbance, such as pale skin, wet cold and low blood pressure; Bradycardia, arrhythmia and even diastolic cardiac arrest may also occur.

(3) Auxiliary inspection

1. Hypokalemia

(1) laboratory test: serum potassium < 3.5 mmol/L.

(2) ECG: T wave decreased, QT prolonged and U wave.

2. Hyperkalemia

(1) Laboratory examination: serum potassium >: 5.5 mmol/L.

(2) ECG: T wave is high and sharp, QT interval is prolonged, QRS wave is widened, and P-R interval is prolonged.

(4) the principle of treatment

1. Find out the causes of hypokalemia and make a potassium supplement plan.

2. Hyperkalemia should actively treat the primary disease, improve renal function, and take the following measures:

(1) Stop the infusion or oral administration of potassium-containing drugs immediately and avoid eating foods with high potassium content.

(2) In case of arrhythmia, 10% calcium gluconate can be added to the same amount of 25% glucose solution for intravenous injection.

(3) Promote the transfer of K+ into cells.

(4) promoting K+ excretion.

(5) Nursing measures

1. Strengthen the monitoring of the dynamic change trend of serum potassium level.

2. Nursing control causes or incentives.

3. The principle of potassium supplementation in patients with hypokalemia.

(1) Try to supplement potassium orally: 10% potassium chloride solution or potassium citrate is often taken orally, and those who cannot take it orally can be given intravenous drip.

(2) It is forbidden to inject potassium intravenously.

(3) see urine potassium supplement: generally, the urine volume exceeds 40 ml/h to supplement potassium. ..

(4) Total amount limit: the amount of potassium supplement is 3 ~ 6g/d potassium chloride.

(5) Control the concentration of potassium supplementation: the concentration of potassium in the rehydration solution should not exceed 40 mmol/L. ..

(6) The dropping speed should not be too fast: the rate of potassium supplementation should not exceed 20 mmol/h. ..

4. For patients with hyperkalemia, 5% sodium bicarbonate or glucose solution is infused with insulin, or oral cation exchange resin or retention enema, or peritoneal dialysis or hemodialysis.

(6) Health education

1. Those who fast for a long time, or who have vomiting and diarrhea recently, should pay attention to timely potassium supplementation to prevent hypokalemia.

2. Patients with renal insufficiency and long-term use of diuretics to inhibit potassium excretion should limit the intake of potassium-containing foods and drugs, and monitor the blood potassium concentration to prevent hyperkalemia.

Fourth, acid-base imbalance.

The pH value of normal body fluid is 7.40 0.05.

(1) etiology

1. Metabolic acidosis is the most common. The main reasons are:

(1) produces too many acidic substances in the body: acid metabolites are constantly produced during severe injury, peritonitis, hypoxia, high fever and shock; Another example is that you can't eat for a long time and the energy supply is insufficient. Excessive fat decomposition in the body forms ketone bodies.

(2) Decreased hydrogen ion excretion: H+ excretion and HCO3- reabsorption of renal tubules were blocked in acute renal failure.

(3) Excessive loss of alkaline substances: diarrhea, biliary fistula, intestinal fistula or pancreatic fistula lead to the loss of a large amount of alkaline digestive juice.

2. The main causes of metabolic alkalosis are:

(1) Too much H+ loss: pyloric obstruction, long-term gastrointestinal decompression, and a lot of H+and Cl- loss.

(2) Excessive intake of alkaline substances: long-term use of alkaline drugs or massive blood transfusion.

(3) Hypokalemia: When potassium is deficient, intracellular potassium shifts to extracellular, and k+-Na+ exchange increases.

(4) The role of diuretics.

3. The common causes of respiratory acidosis are: any disease that can cause alveolar hypoventilation can lead to respiratory acidosis. Such as general anesthesia, excessive sedative, improper management of ventilator, laryngeal or bronchial spasm, acute pulmonary edema, severe pneumothorax, pleural effusion, chronic obstructive pulmonary disease and cardiac arrest.

4. The common causes of respiratory alkalosis are: all factors that cause hyperventilation can lead to respiratory alkalosis. Common in hysteria, high fever, central nervous system diseases, pain, ventilator-assisted ventilation and so on.

(2) Clinical manifestations

1. Mild symptoms of metabolic acidosis are often masked by the primary disease, while serious symptoms may include fatigue, dizziness, lethargy, insensitivity or irritability.

2. Mild metabolic alkalosis often has no obvious manifestations. Heavier patients have shallow breathing, slow breathing or mental disorders.

3. Respiratory acidosis includes chest tightness, shortness of breath, dyspnea, cyanosis and headache, and severe cases may be accompanied by blood pressure drop, delirium and coma. Severe cerebral hypoxia can cause brain edema, cerebral hernia and even respiratory arrest.

4. Most patients with respiratory alkalosis have shortness of breath. May have dizziness, hand, foot and mouth numbness, tingling, muscle tremor, hand and foot convulsions, often accompanied by increased heart rate.

(3) Auxiliary examination of arterial blood gas analysis:

1. metabolic acidosis plasma pH

2. During metabolic alkalosis, plasma pH and HCO3- increased, and PaCO3 was normal.

3. The plasma pH and PaCO3 of respiratory acidosis are increased, and HCO3- can be normal.

4. In patients with respiratory alkalosis, the plasma pH increased, while PaCO3 and HCO3- decreased.

(4) the principle of treatment

1. Metabolic acidosis should be treated actively, and mild metabolic acidosis should be corrected by rehydration.

2. The key to metabolic alkalosis is to remove the cause, and dilute hydrochloric acid solution or arginine hydrochloride solution can be used.

3- Respiratory acidosis actively treats the primary disease, improves the ventilation function, and performs tracheal intubation or tracheotomy when necessary.

4. Respiratory alkalosis should be treated at the same time as the primary disease.

(5) Nursing measures

1. Eliminate or control the risk factors leading to acid-base metabolic disorder, and actively treat the primary disease according to the doctor's advice.

2. Take the medicine according to the doctor's advice and strengthen the observation of the condition. When correcting the acid-base imbalance, we should strengthen the monitoring of the dynamic trend of patients' vital signs, blood electrolytes and blood gas analysis indexes; Find and deal with the corresponding complications in time.

3. Help patients to adopt correct posture.

4. Keep the respiratory tract unobstructed, train patients to take a deep breath and cough effectively. For patients with excessive airway secretions, atomization inhalation of dampness-removing and phlegm-resolving liquid is given to help eliminate phlegm. When necessary, perform ventilator-assisted breathing and do airway care well.

5. Improve and promote the recovery of patients' consciousness, regularly evaluate patients' cognitive ability and orientation, notify the doctor in time if there is any abnormality, and implement various treatments according to the doctor's advice.

6. Reduce the risk of injury, strengthen safety protection, and work out the form, time and quantity of activities together with patients' families.

(6) Health education includes vomiting, diarrhea and high fever. It is easy to lead to acid-base imbalance and should be treated promptly.