RU2185091C1 - Noninvasive method for determining intracranial pressure - Google Patents

Abstract

FIELD: medicine. SUBSTANCE: method involves measuring blood pressure in the retinal central vein. The retinal central vein blood pressure coincides with the intracranial pressure in the cases of patients subjected to no cranial trepanation. Adjustment coefficient is used in the cases of patients subjected to cranial trepanation. Its value is equal to 0.7 when the retinal central vein blood pressure is equal to 10-20 mm of Mercury column. The value being equal to 21-30 and 31-45 mm of Mercury column, the recalculation coefficient is equal to 0.5 and 0.4, respectively. When measuring the retinal central vein blood pressure in mm of Mercury column and multiplying it by the corresponding adjustment coefficient, intracranial pressure is calculated for patients subjected to cranial trepanation. EFFECT: high reliability in investigating intracranial hypertension. 2 tbl

Description

 The alleged invention relates to medicine and can be used in neurosurgery, as well as in neurotraumatology, neurology, physiology and other medical fields.

 In diseases of the brain, syndromes of increased intracranial pressure often occur. In the clinic, these syndromes attract particular attention, since they often progress to an alarming degree and in some cases are the main cause of deaths.

 Diagnosis of increased intracranial pressure is one of the main tasks of neurosurgery, as it is observed in various pathological processes affecting the tissue of the brain and its membranes. Inside the skull, cerebrospinal fluid and intracerebral pressure are distinguished; at the same time, the pressure of the intercellular fluid and the total pressure of the substance of the brain are distinguished in the brain tissue. One of the main causes of impaired brain function is not “pure” cerebrospinal fluid hypertension, but a violation of cerebral blood flow as a result of increased local intracerebral pressure. However, in clinical conditions, intracranial pressure is usually conditionally identified with cerebrospinal fluid. The close morphofunctional relationship of the venous and cerebrospinal fluid systems of the brain, as well as the anatomical and functional feature of the vessels of the ocular fundus, in particular the central retinal vein (CVS), formed the basis for studying the possibilities of ophthalmoretinal reactions (pulsation and pressure in CVS) in assessing intracranial hypertension. Vessels of the fundus are a direct reflection of the vascular system of the brain and their change in violation of the venous and cerebrospinal circulation served as a reason for finding methods for assessing these disorders. The disappearance of pulsation of CVC occurs in all cases of intracranial hypertension verified by lumbar puncture (Berdichevsky M. Ya. Venous discirculatory pathology of the brain. M., 1989). The literature provides data on changes in the pulsation and pressure of the retinal veins with an artificial increase in intracranial pressure during the Kveckenstedt test (Walsh T., Garden I., Gallagher B. Obliteration of retinal venous pulsation during elevation of cerebrospinal fluid pressure.- Am. J. Ophthalmol ., 1969, N 67. Zabolotskikh N.V. Study of patency of the spinal cerebrospinal fluid in ophthalmoretinal reactions. - Methodical recommendations, 1992). However, in-depth studies of pressure changes in CVC with intracranial hypertension have not been conducted.

 An indirect method for determining the increase in intracranial pressure is craniography - a study using targeted snapshots of the skull (Esinovskaya GI. Short manual on neuro-radiology. M., 1973). With a prolonged increase in intracranial pressure, thinning of the bones of the skull (general osteoporosis), shortening and thinning of the back of the Turkish saddle up to its complete destruction, osteoporosis or destruction of the anterior and posterior sphenoid processes, deepening of the Turkish saddle, divergence of cranial sutures, strengthening of the pattern of finger impressions and amplification develops , expansion of the channels of diploic veins, etc.

 It is possible to suggest an increase in intracranial pressure using an examination of the fundus - ophthalmoscopy. At the same time, there is hyperemia of the optic nerve head, swelling and wear of its borders, an increase in its diameter and standing in the vitreous body, narrowing of the arteries, expansion, plethora and tortuosity of the veins in the fundus.

LIMITATIONS:
1. Changes detected by craniography and ophthalmoscopy reveal indirect signs of increased intracranial pressure, do not allow to quantify the degree of increase in pressure inside the skull.

 2. X-ray signs of increased intracranial pressure appear no earlier than a month after its occurrence, and changes in the fundus - in a few days.

3. Congestion of the optic nerves is detected not only with intracranial hypertension, but also with other diseases (tuberculous meningitis, sinus thrombosis, thrombophlebitis of the cortical veins, etc.)
As a prototype of the selected method of measuring pressure during ventricular puncture - puncture of the posterior or anterior horn of the lateral ventricle. Under local anesthesia in the supine position, milling holes are applied at the Dandy point when the posterior horn of the lateral ventricle is punctured, located 3.0 cm lateral and 3.0 cm above the external occipital protuberance. A graduated blunt cannula for ventricular puncture is directed to the upper outer edge of the orbit of the same side. Normally, in an adult, the cannula penetrates the horn at a depth of 6-7 cm.When puncture of the anterior horn of the lateral ventricle, a milling hole is placed at the Kocher point 2 cm anterior to the coronary suture and 2 cm lateral sagittal suture. The cannula is advanced in a plane parallel to the sagittal in the direction of the imaginary line connecting the external auditory canals. Moreover, normally at a depth of 5-5.5 cm, it penetrates the ventricle. Without releasing liquor, a manometer is connected through the cannula, which is a graduated glass tube with a diameter of 0.2 cm, each centimeter of which is equal to 10 mm of water. pillar. The pressure in the lateral ventricle is normally 160-190 mm. (Irger I.M. Neurosurgery. M., 1982). An increase in pressure in the lateral ventricles is regarded as intracranial hypertension. The disadvantages of the prototype:
1. Ventricular puncture is a surgical procedure. The method is traumatic, invasive, unsafe for the patient, can be performed only for health reasons.

 2. Catheterization of the lateral ventricle is associated with certain methodological difficulties and can only be carried out by a specialist who knows this technique and only in stationary conditions, which limits the use of this technique in a clinical setting, especially at a pre-hospital level.

TASKS:
1. Reducing trauma.

 2. Reduced labor costs.

 3. The simplification of the method.

 4. Elimination of the risk of diagnosis.

SUMMARY OF THE INVENTION - lies in the fact that:
Intracranial pressure is determined by measuring pressure in the CVC. In patients without craniotomy, the pressure in the CVC corresponds to intracranial pressure. In patients with craniotomy, a correction factor is used: at a pressure in the CVC equal to 10-20 mmHg, the correction coefficient is 0.7; at a pressure in the CVS - 21-30 mm Hg and 31-45 mm Hg the conversion factor is 0.5 and 0.4, respectively. By measuring the pressure in the CVC in mmHg and multiplying it by the corresponding correction factor, intracranial pressure, expressed in mmHg, is obtained. in patients with craniotomy. Thus, we have proposed a non-invasive method for the quantitative determination of intracranial pressure, which involves the measurement of pressure in the central retinal vein. Pressure is measured in mmHg.

 SUBSTANTIATION OF NOVELTY. A patent study showed that to date, the proposed method for determining intracranial pressure has not been previously described and has not been used. Publications and patents in domestic and foreign literature not found.

 INVENTIVE LEVEL is confirmed by non-obviousness.

 The reproducibility of the method is not in doubt, because well-known techniques and equipment were used, as well as a process available to medical personnel.

IMPLEMENTATION OF THE METHOD
The method is as follows.

 The pressure in the CVC is measured by an OM-1 electronic ophthalmic dynamometer in the horizontal position of the patient after anesthesia of the sclera with a 0.1% dicain solution and dilated pupils with a 0.5% amisil solution. At the fundus there is a CVS located in the optic nerve disk. It differs from arterial vessels in large diameter, intensity of staining and, in some cases, spontaneous pulsation. With simultaneous ophthalmoscopy of the optic nerve head with an OP-2 ophthalmoscope using an ophthalmic dynamometer sensor, pressure is applied to the outer surface of the sclera of the eyeball quickly, evenly, without jerking. For diastolic pressure in the CVC, the lowest values of the ophthalmic dynamometer are taken with three times determination, corresponding to the appearance of the maximum pulsation of the CVC. The values in grams obtained on the scale of the ophthalmic dynamometer, taking into account the level of intraocular pressure, are converted to mmHg. according to the Mazhito-Bayar table (Katsnelson L.A. Ophthalmodynamometry. - In the book: A multivolume guide to eye diseases, issue 1, volume 2. Edited by V.N. Arkhangelsky. M., 1962).

 Measurement of intracranial pressure is performed by puncture of the lateral ventricle during neurosurgical operations with a manometer, which is a graduated tube with a diameter of 0.2 mm, each centimeter of which is 10 mm. water Art. Mm water Art. translated in mmHg

 A parallel measurement of the pressure in the CVC and intracranial pressure by means of a puncture of the lateral ventricle was performed in 42 patients without craniotomy and in 46 patients with a trephined skull aged 11 to 61 years, 30 women, 58 men. All the patients studied were in the intensive care unit of the Regional Clinical Hospital named after S.V. Ochapovsky, Krasnodar in serious condition (coma I - III), he underwent mechanical ventilation in the mode of normal and moderate hyperventilation. At the same time, the pressure in the CVC was determined for each patient three times while in the hospital with both eyes, lateral ventricular puncture was performed 2 times in 48 patients, 3 times in 34 patients, and 6 in 6 patients.

Patients are divided into 2 groups:
Group I - (n = 42) patients who did not undergo craniotomy. In this group, the pressure in the CVC corresponded to the pressure in the lateral ventricles, expressed in mmHg. The correlation coefficient is 0.9.

Group II - (n = 46) patients who were measured for pressure in the CVC and in the lateral ventricles against the background of craniotomy. Depending on the pressure in the CVC and in the lateral ventricles, group II is divided into subgroups:
1 subgroup - (n = 14) the pressure in the CVC is 10-20 mmHg, on average - 16.8 ± 0.34. The pressure in the lateral ventricles was on average 11.5 ± 0.26 mm Hg.

 2 subgroup - (n = 22) the pressure in the CVC is 21-30 mmHg, on average - 23.4 ± 0.3. The pressure in the lateral ventricles was on average 12.5 ± 0.19 mm Hg.

 Subgroup 3 - (n = 10) the pressure in the CVC is 31-45 mm Hg, on average - 36.9 ± 0.83. The pressure in the lateral ventricles was 15.7 ± 0.25 mm Hg.

 In each group and subgroups, a correlation analysis was performed between the pressure in the CVC and the pressure in the lateral ventricles, and the coefficient for converting the pressure in the CVC to intracranial pressure was calculated. The correction factor for recalculating the CVC pressure into the pressure in the lateral ventricle was obtained by dividing the arithmetic mean of the pressure in the CVC by the arithmetic average of the pressure in the lateral ventricle in each subgroup of patients.

 Table 1.

Correlation analysis between pressure in CVC and intracranial pressure in patients with craniotomy
Pressure in CVC mmHg - R
10-20 (16.78 ± 0.34) - 0.67
21-30 (23.4 ± 0.3) - 0.53
31-45 (36.9 ± 0.83) - 0.49
As can be seen from table 1 revealed a reliable correlation between the studied indicators.

 Table 2.

Coefficient of conversion of pressure in CVC to intracranial pressure in patients with craniotomy
Pressure in CVC mmHg - K
10-20 - 0.7
21-30 - 0.5
31-45 - 0.4
The study of intracranial pressure by measuring pressure in a CVC using a conversion factor has not been previously studied. The application of this method does not require expensive equipment and can be used an unlimited number of times.

 Thus, in order to measure intracranial pressure, it is enough to study the pressure in the CVC. The obtained pressure value in the CVC corresponds to ventricular pressure in patients without craniotomy, expressed in mm RT. Art. In patients with craniotomy with a pressure in the CVC of 10-20 mm Hg the correction factor is 0.7, i.e. the resulting pressure figure in the CVC in mm RT. Art. need to be multiplied by 0.7 to obtain the value of intracranial pressure in mm RT. Art. At a pressure in the CVC of 21-30 mm Hg, the conversion factor is 0.5; at a pressure in the CVS 31-45 mm RT.article - correction factor conversion - 0.4.

 Example 1. B-th Ragimov A. M., 11 years old. The history of the disease is 9638. Diagnosis: meningosarcoma, coma I. Pressure research in CVS and lateral ventricles was carried out before surgery in the absence of craniotomy, therefore, the conversion factor for the quantitative measurement of intracranial pressure was not used.

 When measuring the pressure in the CVC, it amounted to 18.1 mm Hg. When measuring pressure in the anterior horn of the lateral ventricle, it was 18.2 mmHg. Thus, the value of intracranial pressure obtained by measuring the pressure in the CVC corresponds to the numbers obtained by measuring the ventricular pressure.

 Example 2. B. Davydenko G.V., 32 years old. Case history 3986. Diagnosis: arteriovenous malformation, subarachnoid hemorrhage, coma II-III. Studies were conducted in the absence of craniotomy.

 When measuring the pressure in the CVC, it amounted to 27.7 mm Hg. When measuring pressure in the posterior horn of the lateral ventricle, it was 27.3 mmHg. Thus, the numbers of intracranial pressure measured by examining the pressure in the CVC are the same as those obtained by puncture of the posterior horn of the lateral ventricle.

 Example 3. B. Makoretkin F.V., 29 years old. Case history 5729. Diagnosis: multiple volumetric foci of the left temporal lobe, coma III. Studies were performed without craniotomy.

 When measuring the pressure in the CVC, it amounted to 39.6 mm Hg. When measuring intracranial pressure by means of puncture of the anterior horn of lateral pressure, it amounted to 39.9 mmHg, which corresponds to the figures obtained when measuring pressure in CVC.

 Example 4. B-Voznesensky A.I., 50 years old. Case history 5730. Diagnosis: TBI, severe brain contusion, intracerebral hematoma, coma I. Measurements were taken during surgery.

 The pressure in the CVC was 18.9 mmHg, which corresponds to the 1st subgroup, where the coefficient for converting the pressure in the CVC to intracranial pressure is 0.7.

 To obtain intracranial pressure, we multiply the pressure figure in CVS -18.9 by a conversion factor of 0.7, and we obtain intracranial pressure equal to 13.2 mmHg.

18.9x0.7 = 13.2 (mmHg)
When measuring the pressure in the anterior horn of the lateral ventricle, the ventricular pressure was 13.3 mmHg. Thus, the intracranial pressure calculated by the pressure in the CVC using the conversion factor corresponds to the numbers obtained by measuring the intracranial pressure by ventricular puncture using the invasive method.

 Example 5. B. Penchuk G.P., 28 years old. Medical history 6945. Diagnosis: cerebellar tumor. Measurements were taken during surgery.

 The pressure in the CVS is 26.2 mmHg. The conversion factor in this subgroup is 0.5. To obtain intracranial pressure, the obtained pressure value in the CVC is 26.2 mm Hg. multiply by a conversion factor of 0.5.

26.2x0.5 = 13.1
The obtained value of intracranial pressure is 13.1 mm Hg. When measuring the pressure in the lateral ventricles, it was 13.3 mm Hg. Thus, the intracranial pressure calculated from the pressure in the CVS using the conversion factor corresponds to the ventricular pressure measured in an invasive way.

 Example 6. B-th Baryshnikova NN, 51 years old. Case history 3335. Diagnosis: subarachnoid hemorrhage, anterior cerebral artery aneurysm, coma III. Measurement of pressure in CVC and in the lateral ventricles was performed during surgery on the background of craniotomy.

The pressure in the CVC was 41.8 mmHg, which corresponds to subgroup III. The conversion factor in this subgroup is 0.4. To obtain a quantitative value of intracranial pressure, we multiply the obtained pressure value in the CVC by a conversion factor of 0.4
41.8x0.4 = 16.7
The resulting intracranial pressure, calculated by the non-invasive method from the pressure in the CVC, was 16.7 mmHg. When measuring ventricular pressure, it was 16.3 mmHg. Thus, the intracranial pressure measured by ventricular puncture corresponds to the intracranial pressure calculated from the pressure in the CVC using the conversion factor.

 MEDICAL-SOCIAL EFFECT - to increase the reliability of the study of intracranial hypertension, which makes it possible to timely determine the degree of this condition and conduct its corresponding correction. Compared with the prototype, this method allows you to explore intracranial pressure without resorting to traumatic and invasive manipulation. The results of the study can be used for the early diagnosis of intracranial hypertension at the prehospital stage and for the dynamic study of intracranial pressure during treatment and rehabilitation of patients.

Claims (1)

 A non-invasive method for determining intracranial pressure in patients with craniotomy, including measuring pressure in the central retinal vein (CVC), characterized in that when the pressure in the CVC is 10-20 mmHg. Art. the resulting pressure figure is multiplied by 0.7, at 21-30 mm RT. Art. - by 0.5, and at a pressure in the CVC above 31 mm RT. Art. - by 0.4.