In clinical work, we are familiar with patients with hypokalemia and hypocalcemia, and practice makes perfect in medication. For patients with hypophosphatemia, as a nurse, what should I pay attention to when taking drugs? Let's look at a few cases.

1 case review

Case 1

1 A patient with multiple myeloma was in the period of bone marrow suppression after autologous hematopoietic stem cell transplantation. Due to the influence of high-dose chemotherapy, he developed oral ulcers, lost appetite, and did not eat for five consecutive days.

Electrolyte results showed that blood calcium was 65438 0.7 mmol/L and blood phosphorus was 0.77 mmol/L.

The doctor prescribed 500 ml of 10% glucose injection+10% calcium gluconate 10ml+2ml compound potassium hydrogen phosphate injection, qd intravenous drip.

In the process of configuration, the nurse in charge found that there was white turbidity in the infusion bottle, so she discarded it. Suspected that the syringe used for dispensing was mixed with other drugs, and a batch of doctors' orders for phosphorus supplementation were filled in.

The next day, another nurse in charge used up 500 ml of 10% glucose injection in the department, so she injected 5 ml of 10% calcium gluconate and 1ml compound potassium hydrogen phosphate into two 250 ml bottles of 10% glucose injection respectively. After standing for 5 minutes, one bottle was found to be white and turbid, and the other bottle was colorless and transparent.

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After allogeneic hematopoietic stem cell transplantation, the heart function of a leukemia patient is damaged, so it is necessary to limit the intake. The doctor changed the previous order from "500ml5% glucose injection +2ml compound potassium hydrogen phosphate" to "100ml 5% glucose injection +2ml compound potassium hydrogen phosphate". The superior doctor pointed out that 2ml of compound potassium hydrogen phosphate must be dissolved in at least 400ml of solvent.

2 case studies

Compound potassium hydrogen phosphate injection is colorless and transparent. Clinically, it can be used to supplement phosphorus for patients with moderate surgery or other trauma who need to fast for more than 5 days, and can also be used for hypophosphatemia caused by some diseases.

1. "Compound potassium hydrogen phosphate injection is easy to precipitate when it is compatible with calcium-containing injection, so it is not suitable for use."

These are the original words of the instructions for compound potassium hydrogen phosphate.

In the first case, the patient's blood calcium and phosphorus decrease, and several electrolytes need to be supplemented during infusion. Nurses used to think that compound potassium hydrogen phosphate, like potassium chloride, can be mixed with other electrolytes to supplement, which leads to the discoloration of the solution after preparation.

Compound potassium hydrogen phosphate is not as common as potassium chloride. For unfamiliar drugs, nurses need to carefully consult the drug instructions and strictly grasp the indications of combined drugs.

Studies have proved that there are also drugs that are incompatible with compound potassium hydrogen phosphate:

After mixing with vitamin K 1, the liquid immediately becomes turbid and white flocs appear;

When mixed with 12 multivitamins, yellow flocculent precipitate appears, and with the passage of time, a layer of yellow oily substance adheres to the syringe wall.

Mix with lansoprazole for injection to produce light black.

2. The dilution of compound potassium hydrogen phosphate is special.

The instruction notes that:

Direct injection of compound potassium hydrogen phosphate is strictly prohibited, and it must be diluted more than 200 times under the guidance of a doctor before intravenous drip, and attention should be paid to controlling the dripping speed;

For patients with limited intake, potassium hydrogen phosphate complex should not be directly injected or diluted;

The infusion time of 500ml diluent is generally maintained at about 4 hours.

In addition, in the process of using compound potassium hydrogen phosphate, we should pay attention to tracking the patient's blood phosphorus with the doctor to prevent hyperphosphatemia.

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Knowledge expansion

Severe hypophosphatemia can cause energy metabolism disorder and intracellular energy crisis. In severe cases, it will affect nerve conduction and muscle contraction, resulting in muscle weakness, hyporeflexia, convulsion or coma, respiratory failure, and even endanger the life of patients.

Etiology of hypophosphatemia

① Patients often cannot eat effectively due to mechanical ventilation treatment; Due to the treatment with glucose solution or total parenteral nutrition, the phosphorus intake from food is reduced.

② Injecting glucose during fluid replacement can promote liver phosphorylation, and make phosphorus transfer from extracellular to intracellular; Amino acids in the intravenous hypernutrient solution not only synthesize protein in vivo, but also transport phosphorus to cells. If phosphorus is not supplemented, it will cause hypophosphatemia.

③ Some patients have obvious water retention, pulmonary edema and brain edema. It needs to be treated with dehydrating agents and diuretics to increase the amount of phosphorus discharged from the kidney and reduce blood phosphorus.

④ Patients often have different degrees of acid-base imbalance, and acidosis can reduce the glycolysis of grapes, increase the concentration of serum phosphate and strengthen the excretion of urine phosphorus; Shallow breathing can cause excessive carbon dioxide exhalation, and phosphorus can be transferred to cells during respiratory alkalosis, which can cause severe hypophosphatemia.

⑤ Bacterial and toxin infection can reduce blood phosphorus; Mainly gram-negative bacteria, their endotoxin can cause carbohydrate metabolism disorder, block phosphorus metabolism pathway and reduce blood phosphorus.

⑥ The body produces stress, which increases the secretion of catabolic hormones (such as catecholamine, glucocorticoid, glucagon, thyroxine, etc.). ), leading to accelerated protein and fat decomposition; The heterogeneity of sugar, the increase of sugar production in liver and the increase of blood sugar can make the body in a state of high catabolism, leading to the redistribution of phosphorus in the body, the increase of urinary phosphorus excretion and the decrease of blood phosphorus.

Clinical manifestations of hypophosphatemia

① neuromuscular system: the decrease of blood phosphorus will definitely affect the production of ATP, thus affecting the energy supply and function of neuromuscular cells, which is characterized by abnormal electromyography and electroencephalography. The increase of CK will eventually lead to muscle weakness, hypotonia, disappearance of tendon reflex and disturbance of consciousness of limbs;

Respiratory system: low phosphorus reduces ATP production, which makes respiratory muscles easy to fatigue, leads to the decrease of transmembrane pressure and induces respiratory failure; At the same time, low phosphorus can reduce the production of alveolar surfactant, cause alveolar interception, and further aggravate respiratory failure;

③ circulatory system: when phosphorus is low, energy production and supply decrease, myocardial contractility weakens, and creatine kinase (CK) rises rapidly, which may cause congestive heart failure; In addition, heart failure can also cause low blood phosphorus, forming a vicious circle;

④ Blood system: The plasticity of erythrocyte morphology depends on the amount of ATP on erythrocyte membrane. When the phosphorus content is low, ATP decreases. It has been found that hemolysis can occur when the ATP content on erythrocyte membrane is lower than normal 15%. The effect of low phosphorus on leukocyte function is mainly manifested in the mechanical function of granulocytes. When the blood phosphorus drops below 0.6mmol/L, the chemotaxis and phagocytosis of leukocytes decrease, and the anti-infection ability decreases.

Treatment of hypophosphatemia

① Remove the inducement and treat the primary disease;

② Intravenous drip of compound potassium hydrogen phosphate and oral administration of sodium phosphate or potassium phosphate;

③ Increase the intake of foods rich in phosphorus, such as nuts and soybeans.

References:

[1] Gu Yanping, Shen, Compatibility of compound potassium hydrogen phosphate injection with 12 multivitamin (Weimeijia) is contraindicated [J]. Medical equipment, 20 15, (7):63-63.

Lin Lilian. Contraindications between compound potassium hydrogen phosphate injection and vitamin K 1 injection and calcium gluconate injection [J]. China Kang Min medicine, 20 14, (1 1): 67-67.

[3] Zhang Jianqun. Clinical significance and research progress of hypophosphatemia in critically ill patients [J]. Application of Modern Drugs in China, 20 14, (12):240-242.