Overview
Intensive care of craniocerebral injury [ICU], for the treatment of patients with critical craniocerebral injury has a guiding significance, is an important measure to improve the cure rate and reduce mortality. The implementation of intensive care for craniocerebral injury is as follows.
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Intracranial pressure monitoring
Neurological function monitoring
Cardiac monitoring
Arterial blood pressure monitoring
Central Venous Pressure Monitoring
Respiratory function monitoring
Oxygen saturation monitoring
Temperature monitoring
Cerebral blood flow monitoring
Brain tissue oxygenation and metabolism monitoring
Section I. Intracranial pressure monitoring
Intracranial pressure monitoring is a method that uses sensors and monitors to continuously measure intracranial pressure to observe dynamic changes in intracranial pressure. Intracranial pressure monitoring can understand the status of intracranial pressure after injury, and has a more important reference value in the diagnosis and treatment of craniocerebral injury and prognosis judgment.
Guilllance was the first to apply intracranial pressure monitoring in experiments in 1951, and lunberg was the first to use it in clinical practice in 1960. At present, it has been widely used in clinical practice in China, and about 50% of patients in neurosurgical intensive care units use intracranial pressure monitoring. In addition to understanding ICP, it can also be used to monitor cerebral perfusion pressure cpp.
1.Indications for intracranial pressure monitoring
Severe craniocerebral injury GCS8 and CT brain scan have a sign, whether preoperative or postoperative are suitable for intracranial pressure monitoring.
Mild or heavy craniocerebral injury GCS9~15, post-injury CT brain scan review found that the injury focal enlargement or hematoma, aggravated but do not need surgery, intracranial pressure monitoring is feasible.
Those who have had shock hypoxemia and hypercapnia after injury often have a tendency of increased cerebral edema and increased intracranial pressure, and intracranial pressure monitoring is also valuable.
2.Types of intracranial pressure monitoring
Non-invasive intracranial pressure monitoring
Invasive intracranial pressure monitoring.
Intracerebral parenchymal method
Epidural method
Subarachnoid intubation method
intracerebroventricular intubation
Subdural method
3.Intracranial pressure grading.
At present, the following international standards are adopted
Normal, pressure of 0.7~2.0kPa (5~15mmHg)
Mildly increased, pressure of 2.1~2.7kPa (16~20mmHg)
Moderate increase, pressure 2.8~5.3kPa (21~40mmHg)
Severe increase, pressure of 5.4kPa (40mmHg)
Cpp should be maintained above 9.3kPa to prevent cerebral ischemia and hypoxia.
4.Intracranial pressure waveform
Normal waveform is a flat pressure curve without rapid and large increase, and the pressure level is normal or can be increased.
Abnormal waveform can be divided into A wave and B wave
A wave, also known as plateau wave, is a pressure waveform formed when the pressure suddenly rises to 6.7~13.2kPa (50~100mmHg), lasts for 5~20 minutes and then drops to the original level or lower, and its appearance time is not regular. If a plateau wave appears, it indicates an increase in intracranial pressure and the condition is in a serious stage.
B wave, also known as rhythmic shock wave, appears 0.5~2 times per minute, with a height of 0~6.7kPa (0~50mmHg), and has no clinical significance.
The relationship of the above waveforms, A wave indicates that the cranial cavity compensatory function is frequently failing, which is a very urgent signal. B wave is the prelude of A wave, which indicates that the brain compliance is reduced, that is, the reduction of cerebrospinal fluid and cerebral blood volume can no longer relieve intracranial hypertension, mostly due to the cerebrovascular autoregulation dysfunction and other reasons.
5.Application value
The changes of increased intracranial pressure expressed by intracranial pressure monitors often precede the manifestation of increased clinical ICP. Therefore, intracranial pressure monitoring can play the role of early alarm. Through intracranial pressure monitoring, it can accurately understand the changes of intracranial pressure, reasonably apply cranial pressure-lowering measures and reduce the blindness of treatment. More importantly, it is conducive to early detection of late or post-surgical complications of intracranial hematoma and and other lesions causing increased ICP, and timely surgical treatment.
Neurological function monitoring
Consciousness monitoring
Pupillary monitoring
Motor function monitoring
Physiological reflex monitoring
Pathological reflex monitoring
Meningeal stimulation sign monitoring
Section 2 Neurological monitoring Consciousness monitoring
The patient’s state of consciousness is determined by the degree of response to stimuli (speech or pain), the level of arousal and the duration of maintenance of arousal. Altered state of consciousness is the basic manifestation of brain function, and its degree is generally consistent with the degree of brain dysfunction.
6.Pupillary monitoring
In monitoring, we should pay attention to the relationship between pupil changes and the state of consciousness, motor function and the relationship between various reflexes.
The size and shape of the pupils and their symmetry and light reflexes are used to determine the extent of cranio-cerebral injury and possible problems. Under normal conditions, the pupils are rounded bilaterally, with direct and indirect light reflexes. The pupils are generally 2 to 5 mm in diameter, less than 2 mm for a narrow pupil and greater than 6 mm for a dilated pupil. During pupil observation, special attention should be paid to the presence of impaired consciousness.
7.Motor function monitoring
By instructing the casualty to complete the movement actively or stimulating the patient with impaired consciousness (orbital pressure, painful stimulation of the trunk or limbs) to passively produce movement and observe the natural position of the limbs to determine the muscle strength and clarify whether there is a disorder of the motor system.
8.Physiological reflex monitoring
Superficial reflexes include corneal reflex, abdominal wall reflex, tic reflex, etc. Severe impairment of consciousness after cranial injury makes the superficial reflexes disappear. The presence, disappearance or appearance of the superficial reflexes reflect the degree of brain tissue damage and the recovery of neurological function. Deep reflexes refer to all kinds of tendon reflexes. All kinds of tendon reflexes disappear in deep coma, and deep reflexes can be elicited when the impairment of consciousness is mild.
9.Pathological reflex monitoring
The appearance of pathological reflexes such as Hoffman’s sign and Babinski’s sign indicates obvious brain damage. Unilateral pathological reflexes indicate damage to the cone bundle on one side, while bilateral pathological reflexes indicate extensive brain damage or alarming liver damage.
10, meningeal stimulation sign monitoring
Cerebral contusion or subarachnoid hemorrhage can appear with cervical tonicity and positive Kirsch’s sign and other signs of meningeal stimulation.
Section III cardiac monitoring
Patients with craniocerebral injury, especially heavy craniocerebral injury, should be monitored with a bedside ECG monitor immediately after injury or surgery to be alert to any heart rate, rhythm or afferent abnormalities. After stabilization, this can be changed to intermittent monitoring and recording.
Patients with severe craniocerebral injury can produce complex and variable electrocardiographic (ECG) changes, which can show signs of heart rate, rhythm, and myocardial ischemia. The most common ECG changes are sinus arrhythmia or ventricular arrhythmia, or in severe cases, atrioventricular block, T-wave hypoplasia and S-T segment prolongation. The general heart rate should be kept at 60~100 beats/min. If it is more than 130 beats/min or less than 60 beats/min, it may affect the hemodynamics and the cerebral blood supply.
11.Factors leading to increased heart rate
Blood loss
Dehydration fever
cerebral contusion
Subarachnoid hemorrhage
Cardiac insufficiency
hyperthermia
Hypoxia
Painful stimulation
Cardiac monitoring
12. Factors leading to slowed heart rate
Increased intracranial pressure
Electrolyte disturbance
Atrioventricular block
Section IV Arterial blood pressure monitoring※Arterial blood pressure monitoring methods
Invasive arterial cannula continuous monitoring.
Non-invasive cuff timing monitoring.
In patients who are critically ill or whose vital signs are unstable after severe craniocerebral injury or craniotomy, blood pressure should be measured by direct arterial cannulation, especially the systemic mean arterial pressure, until the vital signs are stable, and then replaced by regular cuff measurements. Every 15 minutes measurement and recording, if the condition is stable, can be changed to 0.5 ~ 1 hour measurement, continuous monitoring and observation 48 ~ 72 hours.
The arterial blood pressure of patients with severe craniocerebral injury is complex and variable, manifesting as too high or too low, and more people with too high blood pressure than those with too low blood pressure.
13.Common causes of hypertension
Excessive intracranial pressure
Cerebral vasospasm due to traumatic subarachnoid hemorrhage.
Pre-existing primary hypertension.
Arterial blood pressure monitoring
14.Common causes of low blood pressure
Insufficient effective circulating blood volume.
Primary brainstem injury with severe impairment of brainstem function.
Intracranial lesion involving the vasomotor center of the brainstem.
Combined with severe injuries to other parts of the body.
Patient has pre-existing heart disease with incomplete compensation.
Arterial blood pressure monitoring
Section V. Central venous pressure monitoring
In terms of hemodynamics, central venous pressure (CVP) is an important indicator to determine the patient’s cardiac function and blood volume status, especially for patients with increased intracranial pressure, so that the amount and rate of intravenous infusion can be selected and adjusted.
15.The central venous pressure of normal people is 0~150pxHO.
If it is low or tends to decrease, it often indicates insufficient blood volume and should increase the infusion volume and speed up the infusion rate.
If the central venous pressure rises and exceeds the normal level, it indicates that the infusion speed is too fast or excessive, and the rehydration should be stopped or slowed down to avoid heart overload and heart failure.
When the right heart failure, it can also cause the central venous pressure to rise.
Section 6: Respiratory monitoring Respiratory monitoring includes respiratory monitoring and ventilator use.
Respiratory monitoring is the monitoring of respiratory rate, amplitude, respiratory status, oxygen saturation and blood gas analysis.
When using the ventilator, the tidal volume, airway pressure and partial pressure of oxygen inhalation should be adjusted before use to confirm the normal working condition of the ventilator before use. Regular clinical observation of the patient’s respiratory rate, respiratory depth, signs of hypoxia (nasal flapping, cyanosis) and lung auscultation is one of the simple and effective sensitive indicators to estimate ah respiratory function, but it does not really reflect its respiratory function; while ventilator monitoring can accurately reflect respiratory function.
Severe craniocerebral injury often leads to the inhibition of the respiratory center and the occurrence of respiratory impairment. If the injury to the subthalamic, pontine and medulla oblongata, more likely to cause central respiratory failure. In addition, the brain injury is complicated by submucosal bronchial hemorrhage, neurogenic pulmonary edema and pulmonary infection, which often makes breathing abnormal. Pathological respiration has tidal breathing, asphyxial respiration, etc. If there is abnormal respiratory frequency and amplitude disease rational respiration, the etiology should be analyzed from various factors of brain injury and the whole body, and timely treatment. Therefore, monitoring respiratory function is necessary for patients with heavy craniocerebral injury.
Respiratory rate is: 10~30 times / min, more than 30 times / min, is too fast breathing; below 10 times / min, is too slow breathing.
Arterial blood gas analysis, in respiratory monitoring has a very important value. It is used to directly measure the partial pressure of oxygen and carbon dioxide.
PaCO2 directly reflects the alveolar ventilation status, and the normal reference value is 4.7kPa~6.0kPa, below 4kPa is hyperventilation; and above 6kPa is CO2 retention, which indicates poor pulmonary ventilation and should be treated promptly.
PaO2 indicates the partial pressure of oxygen in arterial blood gas, and the normal reference value is 8kPa~13.3kPa. For patients with heavy craniocerebral injury, it is required to maintain the partial pressure of oxygen above 10.7kPa. Below 10.7kPa is hypoxemia and should be treated promptly. Below 8kPa for severe hypoxemia, is respiratory failure, should be given to support breathing and other treatment.
Arterial blood gas analysis is of great value in respiratory monitoring. It is used to directly measure the partial pressure of oxygen and carbon dioxide.
Also monitor the blood pH (PH) residual base (BE) bicarbonate (HCO3) and other items, can understand whether there is an acid-base imbalance in the body. A series of respiratory monitoring indicators can also be calculated with reference to inspiratory oxygen concentration (FIO2), hemoglobin (Hb), blood pH (PH), and oxygen saturation (SaO2). These indicators suggest the interrelationship between multiple quantities and are therefore sometimes more instructive than purely visual indicators.
Section 7: Oxygen saturation monitoring,Oxygen saturation monitoring methods
Intermittent blood gas analysis.
The arterial oxygen saturation (SaO2) method.
Continuous pulse oximetry (Sp02) monitoring method.
Sp02 is continuously monitored by pulse oximetry, which can be more sensitive and can count pulses at the same time. Pulse oximetry Sp02 has been commonly used for intensive care and surgical anesthesia procedures. When SaO2 is less than 70%, its 95% confidence limit accuracy is 4%, which shows that Sp02 is an accurate indicator of arterial blood oxygen and status.
Oxygen saturation monitoring
Inherent characteristics of the oxygen dissociation curve
PaO2>100mmHg is equivalent to SaO299%~100%
PaO2=80mmHg corresponds to SaO294.5%~95%,
PaO2=60mmHg equivalent to SaO2>90%
The relationship between blood oxygen saturation and partial pressure of oxygen should be maintained
Sp02 at 95%~100% corresponds to PaO2 >100mmHg
Sp02 less than 95% corresponds to PaO2 less than 80mmHg hypoxemia
Sp02 less than 90% corresponds to PaO2 less than 60mmHg severe hypoxemia
Oxygen saturation monitoring
During the monitoring of pulse oximetry (Sp02), once changes in the condition are detected, consideration should be given to removing the cause of the aggravation of the injury, on the other hand, adjusting the position, improving respiration, and applying mechanical ventilation to assist respiration when appropriate, in order to correct the hypoxic state.
Continuous monitoring of jugular venous saturation (SjvO2) with fiberoptic catheter can detect ischemia and hypoxia in the cerebral hemisphere at an early stage. <50% suggests poor cerebral oxygenation and >75% suggests over-perfusion.
Section 8 Temperature monitoring
Temperature monitoring includes
Continuous brain temperature
intrapulmonary artery temperature (central temperature)
Anal temperature
Esophageal temperature
Body surface temperature monitoring method
Intermittent axillary temperature measurement method
Within 24 to 48 hours of severe brain injury, a continuous monitoring of body temperature or no 2 to 4 hours to take temperature once. Thereafter, the temperature is measured every 6 hours until the body temperature is normal for one consecutive week, to 2 times a day.
Continuous monitoring study of brain temperature and anal temperature in patients with heavy craniocerebral injury, found that these patients are significantly higher after the injury, anal temperature is 0.3~1.2℃ lower than brain temperature. Continuous high body temperature increases cerebral oxygen metabolism, aggravates cerebral hypoxia, and may cause convulsions. Take hibernation hypothermia therapy, the effect is good.
Severe craniocerebral injury patients 48 hours when the body temperature still does not gradually drop.
Then suggest that the hypothalamus or brainstem and other parts of the injury is serious.
Subarachnoid hemorrhage.
Intracranial infection.
Extracranial infections: pneumonia; urinary tract infections, etc.
Elevated body temperature is extremely detrimental to recovery and should be treated promptly and correctly for the cause.
Section 9: Cerebral blood flow monitoring
Transcranial ultrasound Doppler (TCD) can be used as a non-invasive bedside monitoring tool. The middle cerebral artery is generally used to determine the intracranial hemodynamic changes according to its flow velocity, index and waveform. Normal human middle cerebral artery blood flow velocity is 65±425px/s.
Cerebral blood flow monitoring can also be performed by laser Doppler, which continuously monitors local cerebral blood flow (rCBF) changes through an invasive intracranial probe. The average cerebral blood flow in normal adults is approximately: 50±5ml/100g brain tissue.min.
It is generally believed that the mean CBF in the resting state is 76±10ml/100mg brain tissue.min in the gray matter and only 20±4ml/100mg brain tissue.min in the white matter of the brain.
The current pattern of cerebral hemodynamic changes after traumatic brain injury is divided into three phases.
The hypoperfusion period within 24 hours after injury.
The period of cerebral congestion from 1 to 3 days after injury.
The cerebral vasospasm period 4~14 days after injury.
Section X. Monitoring of brain tissue oxygenation and metabolism
In recent years, the development of detection technology has made it possible to use multi-parameter sensors inserted directly into brain tissue to continuously monitor PO2, PCO2, PH, and brain temperature of brain tissue to more directly reflect the oxygenation and metabolism of brain tissue.
The normal range of values is currently considered to be
Local partial pressure of oxygen in brain tissue: (PbrO2) 2.1~5.3kPa.
1.3~2kPa is a mild hypoxic state
<1.2kPa is severe hypoxia
Local partial pressure of carbon dioxide in brain tissue (PbrCO2) 5.3~6.7kPa.
>7.3kPa as brain tissue carbon dioxide accumulation
Local pH of brain tissue (pHbr) 7.01~7.20, <7.00 is acidosis.