What Is an External Ventricular Drain?

Extracorporeal circulation establishment surgery is a part of human surgery, and it has a higher application of medicine. It needs a combination of internal surgery and external surgery to achieve a smooth operation.

Extracorporeal circulation establishment surgery

1. Eliminate all infections. 2. Correct malnutrition, anemia, and liver, kidney and other organ dysfunction.

3. correct

vein

1. Dissection and resection

Treatment of low cardiac output

The normal cardiac output is 2.5 to 4.4 L / m body surface area. The diagnosis of low exhaustion cannot be based on a single sign or symptom, but should be based on the overall condition of the patient. The diagnosis is based on the following: restlessness, anxiety, or indifference; the pulse around is fine and fast; the skin is cold and wet, and the nail bed is cyanotic; the urine is less than 30ml per hour for adults; hypoxemia; blood pressure Mostly low, but the blood pressure can also be normal or high; low cardiac output index <2.5L / m. Dealing with low emissions needs to be targeted, with particular emphasis on prevention.

Low blood volume: Machine blood should be input into the body as far as possible before stopping the extracorporeal circulation, that is, a proper positive balance is required before stopping; the remaining blood in the machine should be slowly input after stopping. Generally requires an average arterial pressure of 8 to 8.66 kPa (60 to 80 mmHg), and a central venous pressure of 2 to 2.67 kPa (15 to 20 mmHg). Immediately after inputting the machine's residual blood, start to input the stock blood. The speed and volume of the input should be adjusted based on hemodynamic changes, urination speed, average arterial pressure, and central venous pressure. However, avoid too much or too much blood or fluid input to avoid overloading the heart or developing pulmonary edema. In some patients, left atrial manometry should be used to guide blood transfusion. When the extracorporeal circulation is terminated, the urine flow is often very fast. At this time, blood volume changes rapidly, and changes in arterial, venous, and left atrial pressures should be closely monitored. Cell hematocrit and hemoglobin can be checked regularly to guide the speed and volume of blood transfusion.

Management of cardiac insufficiency: Patients with low cardiac output after extracorporeal circulation surgery often have increased peripheral vascular resistance. The application of vasodilators can often improve cardiac function and reduce the burden before and after the heart. Patients with severe low emissions can use positive drugs at the same time as vasodilators, which can strengthen the heart and reduce the load on the heart. For example, the application of sodium nitroprusside 0.5 5g / kg · min has a good effect on reducing the load . It should be emphasized that low blood pressure is not a contraindication to the application of sodium nitroprusside. The addition of dopamine 2 to 10 g / kg · min while applying sodium nitroprusside can reduce the pre and post load of the heart, increase cardiac output, and improve the heart. The blood supply of the kidney, raises hypertension, reduces peripheral resistance, improves microcirculation, and often makes the circulation gradually stable. However, adjusting the two drugs to a suitable input speed requires a balance process. After cardiac resuscitation, do not rush to terminate the extracorporeal circulation. A certain period of auxiliary circulation should be given to help the recovery of cardiac function. It will play a role in preventing low excretion. Even after stopping the extracorporeal circulation, if the patient has cardiac insufficiency, it can be recurred Cardiopulmonary bypass is performed to assist the heart to drain blood, which is beneficial for the recovery of cardiac function and often plays a role in treating low excretion. In severe patients, intra-aortic balloon counterpulsation often improves significantly.

(3) Treatment of pericardial obstruction: The key to the treatment of pericardial obstruction is timely diagnosis and prompt treatment, and indecision often leads to catastrophic results. The possibility of pericardial obstruction should be considered in the following points: There are no other factors of clinical cardiac insufficiency (such as poor myocardial protection, incomplete correction of deformities or lesions, insufficient blood flow, etc.), but the performance is low, correcting Those with poor sexual drug response; The chest tube drainage volume is too high, or the drainage volume is particularly small; The chest tube drainage volume suddenly decreases or a clot appears; jugular vein bloating, venous pressure increased; arterial pressure decreased , The pulse pressure difference becomes narrow, and those who do not improve with positive drugs. Once diagnosed, the patient should be rushed into the operating room to remove blood clots, blood accumulation and complete hemostasis. If the situation is tight, open the lower section of the incision in the ward, and use a finger wearing disinfection gloves to reach the pericardium. There was a blood clot out, and the condition improved immediately, and then rushed to the operating room for thorough treatment. It should be noted that pericardial obstruction can occur within 3 days after surgery, and delayed pericardial obstruction can still occur thereafter.

Management of heart rhythm disorders

The main cause of cardiac rhythm disturbances after cardiopulmonary bypass is hypokalemia. Therefore, preventing hypokalemia is an important part of preventing heart rhythm disorders. The potassium deficiency in the body should be fully corrected before the operation. The potassium should be given routinely during the operation, and the potassium should be supplemented according to the urine volume and blood potassium measurement results after the operation.

management of supraventricular tachycardia: Isopadine 5 ~ 10mg intravenous injection, is currently the drug of choice. propranolol 10 mg orally or aminoacid 25 mg orally. Intravenous injection of 5 ~ 10mg or intramuscular injection of 10 ~ 20mg. Excited vagus nerve drugs, such as neostigmine 0.5 ~ 1.0mg intramuscular injection. Intravenous injection of phenytoin sodium 100mg. Potassium chloride can be used for 0.4% 0.6% static point. Cotoneaster foxgloves: 0.4 to 0.8 mg intravenous injection of cedilan (unused), 0.1 to 0.2 mg intravenous injection every 2 hours, and no more than 1.2 mg within 24 hours. Synchronous direct current cardioversion: This method can be used for various drugs that are not effective, but it is not suitable for foxglove poisoning. Suppression of atrial pacing overspeed, pacing at a rate higher than its frequency, and sudden stop of pacing after 20 seconds can often turn into sinus rhythm.

Cardiac atrial fibrillation: Intravenous injection of cedilan or digoxin, or cardioversion or overspeed pacing.

(3) Atrial flutter: Isoptin, -blockers or digitalis preparations and pacing overspeed method are available.

Premature ventricular premature beats: occasional premature ventricular beats need not be treated. When recurring, 50 to 100 mg of lidocaine intravenously or 1 to 3 mg / kg · min intravenously can be used. If it is caused by foxglove poisoning, 50 to 100 mg of sodium phenytoin can be administered intravenously or intravenously.

Ventricular tachycardia: Lidocaine is injected intravenously. If repeated, it can be 1-3 mg / kg · min, intravenous drip. Electric cardioversion.

Treatment of acid-base and electrolyte imbalance

A common acid-base imbalance is metabolic acidosis. Alkali deficiency> 3mmol / L, pH <7.35, PaCO2 <4.0kPa (30mmHg) should be corrected. Calculated as follows:

Total extracellular base loss = mmol of base loss × 0.3 × body weight

5% NaHCO3 was used to supplement 1/2 total alkali deletion. After a half-hour review of blood gas, the amount of further correction was decided.

The most severe electrolyte disturbance after cardiopulmonary bypass is hypokalemia, especially in patients who have been taking diuretics for a long time before surgery. The overall potassium is often low. Although serum potassium can be measured normally, the potassium in myocardial cells may be low. Therefore, maintaining the balance of potassium should start with a strong potassium supplement before surgery. During extracorporeal circulation, it should be supplemented with 1 to 2 mmol / kg / hour. After termination of extracorporeal circulation, potassium should be supplemented according to urine volume. Chlorine supplementation is required for every 500ml of urine 0.7 g to 1.0 g of potassium, and strive to maintain serum potassium at 4 to 5 mmol / L.

Low calcium can often lead to myocardial insufficiency, such as large blood transfusions should be appropriate calcium.

Prevent fluid overload

Due to the application of the hemodilution method or the existence of certain cardiac dysfunction before surgery, there is a certain amount of water retention in the body after the end of extracorporeal circulation. Therefore, the negative fluid balance should be maintained within 72 hours after surgery, especially for cardiac insufficiency, and the input of water and sodium should be strictly controlled. Diuresis often occurs after cardiopulmonary bypass. If the diuresis is not ideal, consideration should be given to whether there is poor cardiac or renal function, or insufficient colloid osmotic pressure. In addition to addressing the cause, diuretics such as rapid urine injections can also be applied. However, attention should be paid to the relationship between diuresis and blood volume, and the relationship between diuresis and hypokalemia. Repeated ion monitoring should be performed to maintain dynamic balance.

Management of bleeding

There is a certain incidence of bleeding after extracorporeal circulation, and the key lies in prevention. That is, during the operation, especially after the termination of extracorporeal circulation, patiently and thoroughly stop bleeding. The postoperative hemorrhage treatment is as follows: replenish fresh blood in equal amounts; input dry frozen plasma; input platelets; use hemostatic agents appropriately. However, if the bleeding is fierce, especially in the dynamic observation, there is no tendency to reduce it, you should take a decisive decision and send the operating room to stop bleeding before the patient has shocked.

Assisted breathing

After cardiopulmonary bypass, if the circulation is stable, there is no possibility of bleeding, no heart rhythm disturbance caused by severe ion disturbance, no pulmonary complications, sufficient spontaneous breathing exchange volume, appropriate breathing frequency (less than 30 times / minute), and normal blood gas analysis results, And the patient is awake and can be extubated in the operating room. However, if the patient has severe heart disease, or if the above conditions are abnormal, artificial respiration is required to ensure sufficient gas exchange to reduce the heart load and facilitate postoperative recovery. 6 to 12 hours of artificial respiration is usually helpful. In the application of artificial respirators, blood gas analysis should be performed several times in a short period of time to adjust the parameters of the ventilator. After determining the appropriate parameters for the patient, the blood gas analysis can be changed to once every 4 to 6 hours, or twice daily. Attention should be paid to the management of the respiratory tract to ensure patency and adequate gas exchange; regularly attract secretions to prevent infection; if synchronization is not ideal, autonomous breathing can be eliminated to ensure sufficient exchange and reduce the burden on the patient. To correctly grasp the conditions required for shutdown: Conscious and directional; Stable circulation without severe heart rhythm disturbance; The spontaneous breathing frequency does not exceed 30 times / minute and the exchange volume is sufficient; Blood gas analysis is normal; No possibility of bleeding . It is also necessary to follow the routine procedures of ventilator applications. Use intermittent forced ventilation (IMV) before the shutdown to gradually reduce the number of IMVs. Finally, stop the machine. The blood gas measurement 1 hour after the shutdown should be in the normal range to prove that the shutdown is appropriate. .

Prevent infection

Prevention of infection should begin before surgery, strictly during surgery, and after surgery. A preventive amount of antibiotics should be used before surgery, which can be started 2 to 3 days before surgery. However, it is important to give a large dose of antibiotics before the surgery on the day of surgery to ensure a certain blood concentration during the operation. The operation, including the establishment of various channels, must strictly adhere to the aseptic operation procedures; a certain amount of antibiotics can be added to the machine during the operation, and a dose of antibiotics is given immediately after the extracorporeal circulation is terminated, and then regularly applied. All infusion and transfusion channels should be kept sterile to prevent contamination.

Prevent high temperature

Bounces after hypothermia are prone to occur on the day of surgery. Therefore, when the body temperature reaches 36.5 , physical cooling should be started, which generally can prevent the occurrence of postoperative high fever. If the body temperature is as high as 38 , in addition to physical cooling, hibernation drugs or antipyretic enemas can be added to reduce the body temperature to normal. range.

Anticoagulant therapy

Warfarin is generally taken at 2 to 10 mg / d starting 24 hours after surgery. Later, it is adjusted according to the measured prothrombin time, and the anticoagulant is not fixed within a certain daily dosage range until it is stable. However, the prothrombin measurement time should gradually increase the interval between days, and finally can be measured once every 1-2 months. It should be noted that the long-term use of many drugs, such as anti-rheumatic drugs, anti-arrhythmic drugs, and barbiturates, interferes with anticoagulation therapy, and patients should be informed.

Closely monitor

Patients should be monitored in the intensive care unit (ICU) after surgery. ECG, heart rate, arterial pressure, and central venous pressure need to be monitored; critically ill patients need to monitor left atrial pressure and even cardiac output. Patients with stable circulation should record once every 15 minutes and critically ill patients once every 5 minutes. Urine volume and drainage of the thoracic drainage tube were recorded every hour. Blood gas analysis, serum potassium, hemoglobin, and hematocrit should be measured regularly as needed. The guardianship staff should be good at observing the development of the condition, and analyze the development trend at any time, and do not wait for obvious abnormalities before paying attention.