Asphyxia resuscitation is a skill that must be mastered by obstetricians, pediatricians and anesthesiologists, midwives and nurses, who are required to be trained and qualified before taking up the job. If a high-risk pregnant woman is in fetal distress and is estimated to be at risk of asphyxia during delivery, the pediatrician should be notified to attend the resuscitation. The ABCDE protocol for resuscitation refers to unobstructed airway, establishment of breathing, restoration of circulation, adjunctive medication, evaluation and monitoring. The focus is on item 1 of the first 3. After the ABC is achieved, medication is rarely needed, and it is a mistake to rush medication without handling the first breath. The specific application requires continuous evaluation to guide decision making as a basis for the next step in the operation. The main indicators of evaluation are respiration, heart rate, and skin color; Apgar score is not an indicator for deciding whether to start resuscitation, let alone a basis for deciding what to do next. Because waiting until the results of the one-minute score are available before starting resuscitation, valuable resuscitation time will be lost, and in actual clinical practice, we do not all wait for the results of the score before resuscitation. The AP-gar score within 1 minute after birth still reflects the basic situation at birth, while the 5-minute score is particularly important for determining the prognosis.
1. General procedures
(1) Fully understand the medical history and prepare the mind and materials for resuscitation, such as personnel, oxygen, warming equipment, disposable suction tube, airbag mask resuscitator, neonatal laryngoscope, battery, small light bulb, endotracheal tube, connector, stethoscope and other instruments for examination, first aid supplies are ready and positioned for immediate access, because the success or failure of resuscitation is closely related to time. Respiratory arrest delays resuscitation by 1 minute, wheezing appears about 2 minutes later, and regular breathing is restored about 4 minutes later.
(2) After delivery of the fetal head, not emergency delivery shoulder, but should immediately squeeze out or use the negative pressure ball to suck out the mucus of the mouth, throat and nose. The newborn should have a good warm environment at birth, with far-infrared radiation warming device is the best, as a last resort, also available in large light incandescent lamps and other temporary warming, but need to be careful not to burn. Immediately after birth, wipe dry the body of amniotic fluid and blood can reduce evaporative heat loss. Because of the unstable thermoregulation of asphyxiated children, once cold will increase metabolism and oxygen consumption to maintain body temperature, and metabolic acidosis, body temperature drops after the slow correction. The newborn should be placed in a mild head-low-foot-high position (≈15°) and then aspirated with a disposable suction tube to remove mucus from the mouth, throat, and nose. Do not suction for more than 10 seconds at a time. Stimulation of the vagus nerve in the deep oropharynx can lead to bradycardia or apnea. If there is meconium contamination of amniotic fluid to prevent deep inhalation, the midwife can use both hands to tighten the chest and immediately use the laryngoscopic endotracheal tube to aspirate and then tactile stimulation to make crying. Each use of laryngoscopic endotracheal intubation and suctioning should be completed within 20 seconds. The negative pressure of those who use electric suction pump should be adjusted at 60-100 mmHg according to the mucus consistency, and the suction tube connection should have a T-shaped finger hole or flute mouth for control during suction.
(3) When the evaluation has spontaneous respiration, heart rate > 100 beats/min, skin ruddy or hand and foot cyanosis, only need to continue to observe. Individuals with normal respiratory heart rate but still have central generalized cyanosis are often the result of blood oxygen only being sufficient to supply normal heart rate but not sufficient for systemic needs or having congenital anomalies. This kind of cyanosis which is not enough for the indication of positive pressure oxygen supply should be given 80% to 100% of the normal pressure oxygen supply, and then gradually reduce the oxygen concentration when the skin color turns red to avoid oxygen toxicity.
(4) No spontaneous breathing or heart rate <100 times / min and still have central cyanosis after giving pure oxygen, must immediately use the balloon mask resuscitator pressure oxygen, the rate is 40 times per minute, the first breath need about 2.94 ~ 3.92kPa (30 ~ 40cmH2O) pressure to expand the lung lobes, later only need 1.47 ~ 1.96kPa (15 ~ 20cmH2O) pressure is sufficient. For poor pulmonary compliance, 1.96-3.92 kPa (20-40 cmH2O) pressure should be given, and most asphyxiated children will improve with this ventilation without other treatment. However, the operator must be familiar with the principle of the device in order to use it correctly and safely.
(5) If the mother has used anesthetics 4 hours before delivery and the newborn is respiratory depressed, give sodium nandrolone.
(6) Without drug inhibition and after 15-30 minutes with the resuscitator, the heart rate > 100 beats/min can stop using the resuscitator, observe the spontaneous respiration, heart rate. 60-100 beats/min has a tendency to increase, continue mask pressure oxygenation; no increase in the use of tracheal intubation pressure oxygenation. If the heart rate is <80 beats/min, add chest cardiac compressions. The pressure should be 1 to 2 cm in the lower 1/3 of the sternum, using both thumb palm method and double finger method, 120 times per minute. 30 seconds without improvement, start medication.
(7) 1:10,000 epinephrine plus equal amount of saline, rapid intratracheal injection, can strengthen the heart and peripheral vascular contraction, so that the heart rate is accelerated, if necessary, can be repeated every 5 minutes, when the heart rate > 100 times / min stop medication. ＜If there is metabolic acidosis at <100 beats/min, sodium bicarbonate is given to those who have established good ventilation at the same time. If the heart rate is normal but the pulse is weak, and the resuscitation effect is not obvious even after the administration of oxygen, then consider the blood volume insufficiency and give volume expansion agent. In acute blood loss greater than 20% of the total, hemoglobin and red blood cell pressure can be normal for a period of time.
The effect of dopamine is related to the size of the dose. Small doses (2μg/kg?min) have the effect of dilating renal and cerebro-pulmonary vessels, increasing urine volume and sodium excretion; medium doses (2-10μg/kg?min) increase cardiac contractility and raise blood pressure; large doses (10-20μg/kg?min) increases vasoconstriction and raises blood pressure. In neonatal asphyxia shock is accompanied by acidosis, pulmonary vasoconstriction, and reduced blood flow, so the treatment is mostly started with a small dose of about 5μg/kg?min or a small dose of half of dobutamine and half of dobutamine, and the dose is gradually increased under close monitoring and observation of heart rate and blood pressure.
2.Post-resuscitation treatment and care
Asphyxia and hypoxia is a big setback for newborns. A momentary improvement does not mean complete recovery. Active post-resuscitation treatment plays a great role in reducing and alleviating complications and improving prognosis.
(1) Pay attention to warmth and try to maintain the body temperature at a neutral temperature of about 36.5°C to reduce oxygen consumption. Closely observe respiration, heart sounds, facial color, peripheral circulation, nerve reflexes and urine and stool. After the respiration is stable and the skin color turns red for half an hour, stop oxygen administration. Respiration is the focus of monitoring, and respiratory score and respiratory count are helpful for post-resuscitation observation. Every 4 hours during the first 12 hours of life, every 8 hours for the next 24 hours, and finally once again at 48 hours after birth. The second evaluation can be stopped if the score is 8 or more, and the prognosis is good. If the situation is still poor after two days, the evaluation can be renewed every 12 hours, and the prognosis is serious. If the number of breaths is increasing and dyspnea is present, the presence of pneumothorax should be considered. If the asphyxiated child’s breathing is close to normal and accelerates after 2 days, this is often a sign of secondary pneumonia. If repeated apnea can be used aminophylline, the first dose of 7-8mg/kg intramuscularly or slowly intravenously (more than 15 minutes) to stimulate the heart, brain, vasodilatation and diuretic, after every 6 hours 0.5 ~ 2mg/kg. too fast intravenous injection, or too large a dose can lead to lower blood pressure, nausea and vomiting and convulsions.
(2) If there is phlegm sound in the larynx, coarse voice when breathing, respiratory arrest or vomiting, disposable suction tube should be applied to keep the airway unobstructed.
If cerebral edema and hypoxic-ischemic encephalopathy are proposed, then on the basis of timely correction of hypoxemia and hypercapnia to ensure oxygen supply to brain tissue, use.
①Tachyphylaxis 1mg/kg intramuscularly or intravenously to reduce intracranial pressure.
②Dexamethasone 0.25-0.5mg/kg 2-4 times daily intramuscularly or intravenously. If the cranial pressure is still high after 2-3 times, switch to 20% mannitol 0.25-0.5g/kg, 4-6 times a day, and gradually reduce the dosage after two days.
③Phenobarbital is used for convulsions, the first dose is 15-20mg/kg intravenously, and the maintenance amount is 5mg/kg?d divided into two injections, this drug can reduce the metabolism of brain tissue and oxygen consumption in addition to antispasmodic, which can prevent and reduce cerebral edema and intracranial hemorrhage, such as combined with Valium 0.1-0.3mg/kg intravenously or/and chloral hydrate 30mg/kg retention enema, the antispasmodic effect is better.
④Dobutamine can be given intravenously in hypotension with normal blood volume and insufficient myocardial contractility.
⑤ In order to maintain the energy metabolism of brain tissue, glucose can be continuously administered intravenously <8mg/kg?min to maintain blood glucose at 2.8-5.0mmol/L (50-90mg/dl). To strengthen supportive treatment, energy combination can be given.
(6) The brain cell metabolism drugs cytarabine and cerebroflucan are being explored in China and can also be considered.
(3) Anyone who has been intubated with tracheal intubation and suspected infection, use antibiotics for prevention.
(4) In case of poor recovery from severe asphyxia, delay the opening time of milk to prevent vomit from causing asphyxia again. If there is no vomiting, elevate the upper body so that the abdominal viscera descend, which facilitates lung expansion and reduces the heart burden and intracranial pressure. For those who cannot tolerate gastric tube feeding, intravenous rehydration of 50-60 ml/kg is required, and the amount of fluid should be limited when there is impaired renal function.