Psychological and psychophysiological methods for studying pain. Pain scale in extreme medicine

Visually analogue scale(YOUR)

The visual analogue scale (VAS) was originally created for use in medicine - on it the patient had to assess the intensity of pain currently experienced. Using the VAS method, on a straight line 10 cm long, the patient notes the intensity of pain. The beginning of the line on the left corresponds to the absence of pain, the end of the segment on the right corresponds to unbearable pain. For convenience of quantitative processing, divisions are applied on the segment every centimeter. The line can be either horizontal or vertical.

The use of VAS is quite common in the medical field because it has the following advantages:

1) the method allows you to determine the actual intensity of pain;

2) most patients, even children (aged 5 years and older), easily learn and correctly use the VAS;

3) the use of VAS allows you to study the distribution of ratings;

4) research results are reproducible over time;

5) more adequate assessment of the treatment effect compared to verbal description of pain. The VAS has been used successfully in many studies to study the effectiveness of therapy.

However, VAS also has certain disadvantages compared to other methods. First, patients can mark the scale quite arbitrarily. Often such marks do not reflect reality and do not correspond to verbal assessments of pain given by the patients themselves. Secondly, the distance to the mark made must be measured, which requires time and accuracy, and errors in measurement are also possible. Third, the VAS is difficult to explain to older patients who do not understand the connection between the line and the position of their mark on it. Finally, photocopying sometimes results in line distortion, which affects the measurement. Therefore, VAS is not considered the optimal method for measuring pain intensity in adults and elderly patients, but is recommended as successful in children.

As already mentioned, in the medical field, the use of VAS in various studies is much more common than in any other field. In particular, this applies to psychology.

The visual analog scale was first described in 1921 by Hayes & Patterson. . Only since 1969 has it become the subject of serious study, after the publication of Aitken’s work, which is still relevant today, due to the small number of works devoted to VAS.

Aitken used this scale in his study to assess the feelings of patients depressive disorder. He believed that a digital system was being imposed on the observer when an analogue system would have been more appropriate.

If different people use the same word, this does not mean that they experience the same emotions - this also applies to the location of the marks on the scale. An emotion experienced twice as intense cannot be correlated with a value multiplied by two. There is a tendency to limit the divisions into categories, since only the most basic ones are usually used. This makes such scales ineffective in studying specific associations to given concepts, for example, the physical magnitude of a stimulus. These scales are unable to mark shades of feelings.

Aitken was convinced that analogies should be visual and not simply phrases, otherwise extreme ratings (eg 0 or 5) would occur too often (Yerkes & Urban 1906).

In his study, patients were asked to mark the intensity of their condition on a visual analogue scale every day for several weeks. In this situation, the scale was indeed very suitable for measuring changes and assessing their importance. However, Dr. Raymond Levy (Department of Psychiatry, Middlesex Hospital Medical School, London) believed that he had underestimated all the difficulties encountered when working with such scales. He suspected that such scales were particularly effective in assessing patients with moderate symptoms, who knew exactly what the doctor meant, who began to use the same terminology. Patients suffering from both moderate and more severe forms of depression experienced difficulties when working with these scales.

Dr. J.P. Watson (Maudsley Hospital, London) believed that the problems of defining the terms and scales that Dr Aitken presented were no different from the problems of using any rating scale. He wondered whether Dr Aitken had evidence that patients were deliberately giving results that they knew were wrong.

Dr Aitken noted that Dr Levy's point was important and he agreed with Dr Watson that it applies to all types of self-assessment. In his experience, patients today use words like "depression" without thinking, but there is no doubt that their words may mean something very different from what psychiatrists meant when they used them. Clarification of the exact nature of the symptom is required, as given in the clinical assessment of all symptoms. Analog scales can accurately determine what patients want to communicate, but not what the doctor intended.

This study explains in some detail why the VAS may be better, more convenient, more reliable, and more valid than measures with scores or limited divisions. It is obvious that people suffering from depression are divided into different categories, and the use of a “digital system” can distort the results from the point of view that the patient simply does not try to think about the intensity of his experiences and chooses one of the extreme values. The use of similar scales, but only with a description of the condition, again gives the feeling that they are choosing for the patient without obtaining a truly reliable result. However, this is only one study in which the object is quite complex psychological state, so that you can unambiguously choose better system measurements for it.

In general, there are not many studies that compare Likert scales and visual analogue scales. For example, in a study conducted by Torrance, Feeny, and Furlong, the VAS was shown to have greater reliability than the Likert scale. . Another study by Flynn comparing a 5-point Likert scale and 65mm. VAS, using the example of measuring coping, shows that subjects, when answering the same question, show higher results when working with a Likert scale, compared to VAS.

Jennifer A. Cowley and Heather Youngblood, in their study in which they compared differences in responses on visual analog, numerical, and mixed scales, report that they found it emotionally more difficult to use analog scales than numerical ones because the divisions were left blank , did not contain explanations.

Scales in which each division contained a detailed textual explanation showed more reliable results than those in which some divisions contained gaps. Also, the advantage of using numerical data, for example, when working with variational analysis, is that in this case it is possible to evaluate certain variable interactions, which is impossible when working with nonparametric data.

However, some researchers may prefer analog scales because, unlike numerical scales, they can use efficient parametric statistical analyses.

Also in this study, mixed scales were used - analogue scales with the addition of various divisions: digital or with selective text explanations. At the same time, the opportunity to put your rating at any point on the scale was preserved.

The mixed scales here showed much higher mean scores than the analog scales. Also, the responses collected from the numerical and mixed scales did not differ much from each other, while the responses from the analog and numerical scales diverged greatly.

Thus, we can conclude that the VAS, like the Likert scale, have their own sets of pros and cons. However, in the first study, as in the last, the main question was raised, which may subsequently become a solution to the problem of choice measuring tool- Can we measure characteristics such as depression, anxiety or any other continuous condition using ordinal scales? IN in this case we should use a nonparametric scale, because by using an ordinal scale, we risk getting a rough result that is far from the true attitude of the subject, as well as losing a significant amount of data.

It is possible that the solution to this issue will also be the idea of ​​​​using mixed scales. Given that numeric and mixed produce higher average grades in many studies, researchers may wonder whether this depends on the fact that the person grades without reference to or in accordance with the numeric and text divisions. While this issue is not yet resolved, researchers can use mixed scales to make it easier for subjects to complete the questionnaire, ensuring the reliability of the results of parametric analysis using analogue data.

Pain rating scales are designed to measure the intensity of pain. The scales allow you to assess the subjective pain experienced by the patient at the time of the study. The most widely used are verbal, visual and digital scales or scales that combine all three assessment options.
Verbal pain rating scales
Verba1 KaIne 5ca1e
The verbal rating scale allows you to assess the intensity of pain through a qualitative verbal assessment. Pain intensity is described in specific terms ranging from 0 (no pain) to 4 (worst pain). From the proposed verbal characteristics, patients choose the one that best reflects the pain they experience.
One of the features of verbal rating scales is that verbal characteristics of the pain description can be presented to patients in a random order. This encourages the patient to select a pain grade that is based on semantic content. 4-point verbal pain rating scale
(Obnbaiz E. E., AcHer Y., 1975) 5-point verbal pain rating scale
(Rgapk A. ^M., Mo1P. M.N., NoSh.R., 1982) No pain 0 No pain 0 Mild pain 1 Mild pain 1 Pain of moderate intensity 2 Pain of moderate intensity 2 Severe pain 3 Severe pain 3 Very severe pain 4
Verba1 OexprYug 8ca1e (Oazyuphobanzson R., Albet M., Pagen E. et al., 1990)
When using a verbal descriptive scale, you need to find out if the patient is experiencing any pain right now. If there is no pain, then his condition is assessed as 0 points. If painful sensations are observed, you should ask: “Would you say that the pain has gotten worse, or the pain is unimaginable, or is this the worst pain you have ever experienced?” If this is the case, then the highest score of 10 points is recorded. If there is neither the first nor the second option, then you need to further clarify: “Can you say that your pain is weak, average (moderate, tolerable, not strong), strong (sharp) or very (especially, excessively) strong (acute) "
Thus, there are six possible pain assessment options:
- no pain;
2 - mild pain;
- moderate pain;
- severe pain;
8 - very severe pain;
10 - unbearable pain.
If the patient experiences pain that cannot be characterized by the proposed characteristics, for example, between moderate (4 points) and severe pain (6 points), then the pain is rated as an odd number that is between these values ​​(5 points).
The Verbal Descriptive Pain Rating Scale can also be used in children over seven years of age who are able to understand and use it. This scale can be useful for assessing both chronic and acute pain.
The scale is equally reliable for younger children school age, and older age groups. In addition, this scale is effective in various ethnic and cultural groups, as well as in adults with Not significant violations cognitive abilities.
Facial pain scale
Race&Rash 5ca1e (B1en, O. e1 a1., 1990)
The facial pain scale was created in 1990 by Blan O. et al. (1990).
The authors developed a scale to optimize the child's assessment of pain intensity using changes in the expression
faces depending on the degree of pain experienced. The scale is represented by pictures of seven faces, with the first face having a neutral expression. The next six faces depict increasing pain. The child should choose the face that he thinks best demonstrates the level of pain he is experiencing (Figure 1).

Rice. 1. Facial pain scale
The Facial Pain Scale has several features compared to other facial pain rating scales. Firstly, she's in to a greater extent is a proportional scale, not an ordinal one. In addition, the advantage of the scale is that it is easier for children to correlate their own pain with a drawing of a face presented on the scale than with a photograph of a face. The simplicity and ease of use of the scale make it possible to use it widely clinical application. The scale has not been validated for use with preschool children.
Modified Facial Pain Scale
Thie Rasev Rush 8sa1e-K.eU1kes1 (PP8-K.)
(Vop BaeyerS. b. e* a1., 2001)
Car1 UOP Baeyer with students from the University of South Africa (Canada) in collaboration with Pat Kesears 11pk modified the facial pain scale, which was called the modified facial pain scale. The authors, instead of seven faces in their version of the scale, left six, while maintaining a neutral facial expression. Each of the images presented on the scale received a digital rating ranging from 0 to 10 points (Fig. 2).

O 2 4 6 8 10
Rice. 2. Modified facial pain scale
Instructions for using the scale:
“Look carefully at this picture, where the faces are drawn, which show how much pain you can have. This face (show the leftmost one) shows a person who is not in pain at all. These faces (show each face from left to right) show people whose pain is increasing, increasing. The face on the right shows a person in unbearable pain. Now show me a face that indicates how much you are hurting at the moment.”
Visual Analog Scale (VAS)
U1$ia1 Apa1o§ie 5ca1e (UAZ)
(NizYkhhop E. S., 1974)
This method of subjective pain assessment involves asking the patient to mark a point on a non-graduated 10 cm line that corresponds to the severity of pain. The left border of the line corresponds to the definition of “no pain”, the right border corresponds to “the worst pain imaginable” (Fig. 3). As a rule, a paper, cardboard or plastic ruler 10 cm long is used.
WITH reverse side The ruler contains centimeter divisions, according to which the doctor (and in foreign clinics this is the responsibility of the nursing staff) marks the obtained value
I 1
No pain More pain
doesn't happen
Rice. 3. Visual analog pain scale
and puts it on the observation sheet. The undoubted advantages of this scale include its simplicity and convenience.
Also, to assess the intensity of pain, you can use a modified visual analogue scale, in which the intensity of pain is also determined by different shades of colors (Fig. 4).
The disadvantage of the VAS is its one-dimensionality, i.e., on this scale the patient notes only the intensity of pain. The emotional component of the pain syndrome introduces significant errors into the VAS score.
During dynamic assessment, a change in pain intensity is considered objective and significant if the current VAS value differs from the previous one by more than 13 mm.
Numerical Pain Scale (NPS)
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(McCaler M., Bebe A., 1993)
Based on the principle stated above, another scale was built - a numerical pain scale (Fig. 5). The ten-centimeter segment is divided by marks corresponding to centimeters. It makes it easier for the patient. Unlike VAS, it is easier to assess pain in digital terms; it determines its intensity on a scale much faster. However, it turned out that during repeated tests the patient, remembering the numerical value of the previous measurement, subconsciously reproduces an intensity that does not actually exist
N-4
012345 678 9 10
Rice. 5. Numerical pain scale
pain, but tends to remain in the region of the previously mentioned values. Even with a feeling of relief, the patient tries to recognize a higher intensity, so as not to provoke the doctor to reduce the dose of opioids, etc. - the so-called symptom of fear of repeated pain. Hence the desire of clinicians to move away from digital values ​​and replace them verbal characteristics pain intensity.
Pain scale B1oeMe et al.
Rash zsa1e oGV1oeSye e1 a1.
(ShoesYe S., 12Ys1a.1. Ya. e1 a1., 1995)
The scale was developed to assess pain intensity in patients with chronic pancreatitis. It includes four criteria:
Frequency of pain attacks.
Pain intensity (pain rating on a VAS scale from 0 to 100).
The need for analgesics to eliminate pain (the maximum severity is the need for morphine).
Lack of performance.
YV!: The scale does not include such characteristics as the duration of the pain attack. Sign Characteristics Rating Frequency of pain attacks No 0 Several times a year (2-12 times/year) 25 Several times a month (24-50 times/year) 50 Several times a week (100-200 times/year) 75 Daily ( more than 300 times/year) 100 Pain intensity No 0 Unbearable 100
Sign Characteristics Assessment Need for analgesics to eliminate pain No 0 Aspirin 1 Tramadol 15 Buprenorphine 80 Morphine 100 Duration of disability during the past year due to pain No 0 1-7 days 25 Up to 1 month 50 Up to 365 days a year 75 Constant 100 1.
When using more than one analgesic, the analgesic requirement for pain relief is equal to 100 (maximum score).
If there is continuous pain, it is also assessed at 100 points.
The rating on the scale is made by summing the ratings for all four characteristics. The pain index is calculated using the formula:
Overall scale rating/4.
The minimum score on the scale is 0, and the maximum is 100 points.
The higher the score, the more intense pain and its impact on the patient.
Observational ICU Pain Rating Scale
Spysa1 Sage Rush O$egua1yup Too1 (SROT)
(OeIpaz S., Rosher M. e1 a1., 2004)
The CPOT scale can be used to assess pain in adult patients in the ICU. It includes four signs, which are presented below:
Facial expression.
Motor reactions.
Muscle tension in the upper limbs.
Speech reactions (in non-intubated) or resistance to the ventilator (in intubated) patients. \ ^ sealants ||1 11 Relaxed, 0 Tensioned "1 Grimace dense P; dressing up dark eyelids) OS! ! ~2 No, SPOKOS 0 shares Protective. 1 I ~ ~ Worried ^ "worries, aggression m 1
1 2" No (race:; s) 1: 7G ic
stay Tense, rigid I Strong tension and rigidity 2 Not intubg. cooks I, does not make noise: no 0 1 _| 0
I Not inguGn, sighs and (not g _] Not ingub "(sobs) I. screams! 1e Intubirch
tilyator "SSOPRO"P1PL> ‘Ch-Intubpr^
Tivlyahim! .ashlyaet, N"> 1Ya"Yuru Intubir*
lator "progivl*. 1 kale conduct 1 (signs. Mig points. Than w reactions of the patient: /s; should accept no myoplegia gi reactions to C total global assessment pl:"chsnka according to school; ^conditioned on the patient* * "beer terg / gg!L'-, G:
TO.". -
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... objectification of pain is one of the intractable problems in the clinical practice of doctors of various specialties.

Currently, to assess the presence, degree, and location of pain in the clinic, they are used (1) psychological, (2) psychophysiological and (3) neurophysiological methods. Most of them are based on a subjective assessment of their feelings by the patient himself.

Most in simple ways quantitative characteristics of pain are the ranking scale (Bonica J.J., 1990).

Numerical ranking scale consists of a sequential series of numbers from 0 to 10. Patients are asked to rate their pain sensations with numbers from 0 (no pain) to 10 (maximum possible pain). Patients can easily learn to use this scale. The scale is simple, visual and easy to fill out and can be used quite often during treatment. This allows you to obtain information about the dynamics of pain: by comparing previous and subsequent indicators of pain, you can judge the effectiveness of the treatment.

Verbal ranking scale consists of a set of words characterizing the intensity of pain. The words are arranged in a row, reflecting the degree of increase in pain, and are numbered sequentially from less severe to greater. Most often used next row descriptors: no pain (0), mild pain (1), moderate pain (2), severe pain (3), very severe (4), and intolerable (unbearable) pain (5). The patient chooses the word that most closely matches his feelings. The scale is easy to use, adequately reflects the patient's pain intensity and can be used to monitor the effectiveness of pain relief. The verbal rating scale data compares well with the results of pain intensity measurements using other scales.

Visual analogue scale(VAS) is a straight line 10 cm long, the beginning of which corresponds to the absence of pain - “no pain.” The end point on the scale reflects excruciating, unbearable pain—“unbearable pain.” The line can be either horizontal or vertical. The patient is asked to make a mark on this line that corresponds to the intensity of the pain he is experiencing at the moment. The distance between the beginning of the line (“no pain”) and the mark made by the patient is measured in centimeters and rounded to the nearest whole. Each centimeter on the visual analogue scale corresponds to 1 point. As a rule, all patients, including children over 5 years of age, easily learn the visual analogue scale and use it correctly.

The visual analog scale is a fairly sensitive method for quantifying pain, and data obtained using the VAS correlates well with other methods of measuring pain intensity.

McGill Pain Questionnaire(McGill Pain Questionnaire). Pain is a complex, multidimensional feeling, which simultaneously reflects the intensity of pain, its sensory and emotional components, therefore, when using one-dimensional ranking scales, the doctor evaluates pain only quantitatively, without taking into account the qualitative features of pain. In the early 70s of the 20th century, R. Melzack developed the McGill Pain Questionnaire, in which all words (descriptors) describing the qualitative characteristics of pain are divided into 20 subclasses (Melzack R., 1975). The McGill Pain Questionnaire has been translated into many languages ​​of the world and has proven its effectiveness high efficiency in multidimensional pain assessment.

In our country, there are several versions of the questionnaire in Russian, but the most successful is the version prepared by employees of the Russian State Medical University, Moscow State University. M.V. Lomonosov and CITO named after. N.N. Priorov (Kuzmenko V.V. et al., 1986), which is given below.

MCGILL PAIN QUESTIONNAIRE

Please read all the definition words and mark only those that most accurately describe your pain. You can mark only one word in any of the 20 columns (rows), but not necessarily in each column (row).

What words can you use to describe your pain? (sensory scale)

(1) 1. pulsating, 2. grasping, 3. jerking, 4. constricting, 5. pounding, 6. gouging.
(2) similar to: 1. electric discharge, 2. electric shock, 3. shot.
(3) 1. stabbing, 2. biting, 3 drilling, 4. drilling, 5. piercing.
(4) 1. sharp, 2. cutting, 3. striping.
(5) 1. pressing, 2. squeezing, 3. pinching, 4. squeezing, 5. crushing.
(6) 1. pulling, 2. twisting, 3. tearing out.
(7) 1. hot, 2. burning, 3. scalding, 4. scorching.
(8) 1. itchy, 2. pinching, 3. corrosive, 4. stinging.
(9) 1. dull, 2. aching, 3. brainy, 4. aching, 5. splitting.
(10) 1. bursting, 2. stretching, 3. tearing, 4. tearing.
(11) 1. diffuse, 2. spreading, 3. penetrating, 4. penetrating.
(12) 1. scratching, 2. raw, 3. tearing, 4. sawing, 5. gnawing.
(13) 1. mute, 2. cramping, 3. chilling.

What feeling does pain cause, what effect does it have on the psyche? (affective scale)

(14) 1. tires, 2. exhausts.
(15) causes a feeling of: 1. nausea, 2. suffocation.
(16) causes feelings of: 1. anxiety, 2. fear, 3. horror.
(17) 1. depresses, 2. irritates, 3. angers, 4. infuriates, 5. drives into despair.
(18) 1. weakens, 2. blinds.
(19) 1. pain-interference, 2. pain-annoyance, 3. pain-suffering, 4. pain-torture, 5. pain-torture.

How do you rate your pain? (evaluative scale)

(20) 1. weak, 2. moderate, 3. strong, 4. strongest, 5. unbearable.

Each subclass consisted of words that were similar in their semantic meaning, but differed in the intensity of the pain sensation they conveyed. The subclasses formed three main classes: a sensory scale, an affective scale and an evaluative (evaluative) scale. Sensory scale descriptors (subclasses 1–13) characterize pain in terms of mechanical or thermal effects, changes in spatial or temporal parameters. The affective scale (14 – 19 subclasses) reflects emotional side pain in terms of tension, fear, anger or vegetative manifestations. The evaluative scale (20th subclass) consists of 5 words expressing the patient’s subjective assessment of pain intensity.

When filling out the questionnaire, the patient selects words that correspond to his feelings at the moment in any of 20 subclasses (not necessarily in each, but only one word in a subclass). Each selected word has a numerical indicator corresponding to the ordinal number of the word in the subclass. The calculation comes down to determining two indicators: (1) index of the number of selected descriptors, which is the sum of the selected words, and (2) pain rank index– the sum of the ordinal numbers of descriptors in subclasses. Both measures can be scored for the sensory and affective scales separately or together. The evaluative scale is essentially a verbal ranking scale in which the selected word corresponds to a certain rank. The obtained data is entered into a table and can be presented in the form of a diagram.

McGill Questionnaire allows you to characterize in dynamics not only the intensity of pain, but also its sensory and emotional components, which can be used in differential diagnosis diseases.

Age factor in assessing pain in children. Children aged 8 years and older can use the same visual analogue scales as adults to assess pain severity - this scale is plotted on a ruler, which should be positioned horizontally.

For children from 3 to 8 years old, when self-assessing the severity of pain, you can use either facial scales (faces in photographs or drawings are lined up in a row, in which the facial expressions of distress gradually intensify) or scales with a color analogy (rulers with increasing brightness of red color, indicating the severity of pain) . Reported high degree similarities in pain severity parameters obtained using the photographic portrait scale and the color analogy scale in children aged 3 to 7 years after surgery.

The use of child behavior scales is the main method for assessing pain in newborns, infants and children aged 1 to 4 years, as well as in children with developmental disorders. In such scales, pain is assessed by facial expression, motor responses of the limbs and trunk, verbal responses, or a combination of behavioral and autonomic changes. In some similar techniques The term "distress" reflects not only pain, but also fear and anxiety. Behavioral scales may underestimate the severity of long-term pain when compared with self-report measures.

During the surgical operations and in conditions intensive care It is advisable to document physiological responses to pain, although these responses may be nonspecific. For example, tachycardia can be caused not only by pain, but also by hypovolemia or hypoxemia. Hence, ( !!! ) it can be difficult to assess the severity of pain in newborns, infants and children aged 1 to 4 years, as well as in children with significant developmental disorders. If clinical picture does not allow certain conclusions to be drawn, one should resort to the use of stress-levelling measures, which include creating comfort, nutrition and analgesia, and the cause of distress can be judged by the effect.

Quantification pain sensitivity refers to integrative indicators reflecting general condition body and its response to physiological or psycho-emotional stress, so measuring pain thresholds is very useful method V comprehensive examination patients. The threshold of pain sensitivity is taken to be the minimum value of the stimulus that is perceived by the test subject as a painful sensation.

Pain threshold determined using instrumental methods, in which various mechanical, thermal or electrical stimuli are used as stimuli (Vasilenko A.M., 1997). The threshold of pain sensitivity is expressed in (1) units of stimulus strength when using methods with increasing intensity, or in (2) units of time when exposed to a stimulus constant force. For example, when measuring pain sensitivity using a strain gauge, which provides a gradual increase in pressure on the skin, the pain threshold is expressed in units of the ratio of pressure force to tip area (kg/cm2). During thermoalgometry with constant temperature thermode, the threshold of pain sensitivity is expressed in seconds - the time from the beginning of exposure to the appearance of pain.

Using methods for quantitative assessment of pain sensitivity, it is possible to (1) detect zones of hyperalgesia in pathology internal organs, (2) trigger points for myofascial pain syndromes, (3) monitor the effectiveness of analgesics, and in some cases (for example, with psychogenic pain syndromes) (4) determine therapeutic tactics.

Electrophysiological methods. To assess patients' pain sensitivity and monitor the effectiveness of pain relief in clinical studies Electrophysiological methods are also used. Most widespread received a technique for recording the nociceptive withdrawal reflex, or RIII reflex.

Nociceptive withdrawal reflex(NRO), or nociceptive flexor reflex, is a typical defensive reflex. for the first time this type protective reflexes that arise in both animals and humans in response to painful irritation, was described by Sherrington in 1910 and has been used clinically since 1960 to objectify pain (Kugekberg E. et al., 1960). Most often, NRO is recorded in response to electrical stimulation of n. suralis or plantar surface of the foot (Vein A.M., 2001; Skljarevski V., Ramadan N.M., 2002). At the same time, NPO can be recorded during painful stimulation of the fingers (Gnezdilova A.V. et al., 1998) and even with heterosegmental stimulation (Syrovegina A.V. et al., 2000).

When recording NPO, two components are distinguished in EMG activity – RII and RIII responses. The RII response has a latent period of 40–60 ms and its appearance is associated with the activation of thick low-threshold A-fibers, while the RIII response occurs with a latent period of 90–130 ms at an intensity of stimulation exceeding the excitation threshold of thin A-fibers. It is believed that the NPO is polysynaptic, the reflex arc of which closes at the level of the spinal cord.

However, there is evidence indicating the possibility of involvement of supraspinal structures in the mechanisms of occurrence of NRA. Direct confirmation of this is studies that compared the characteristics of changes in NPO in intact and spinal rats (Gozariu M. et al., 1997; Weng H.R., Schouenborg J., 2000). In the first study, the authors found that in intact rats, the preservation of supraspinal pain control mechanisms counteracts the development of an increase in NPO amplitude under conditions of prolonged painful stimulation, in contrast to spinal animals. The second paper provides evidence of an increase in NPO inhibitory reactions to heterotopic nociceptive stimuli under conditions of spinalization of animals.

Understanding the fact that supraspinal structures of the brain are involved in the formation of NPO not only expands the diagnostic capabilities of the method, but also makes it possible to use it in the clinic for an objective assessment of the severity of pain not only during homotopic stimulation, but also during heterosegmental pain stimulation.

Method of exteroceptive suppression of voluntary muscle activity in m. masseter. To study the mechanisms of development of headaches and facial pain, the clinic also uses the method of exteroceptive suppression of voluntary muscle activity in the m. masseter (Vein A.M. et al., 1999; Andersen O.K. et al., 1998; Godaux E., Desmendt J.E., 1975; Hansen P.O. et al., 1999). This method is essentially a variation of the nociceptive withdrawal reflex.

It has been established that perioral electrical stimulation causes two successive periods of inhibition in the tonic EMG activity of the masticatory muscles, designated ES1 and ES2 (exteroceptive suppression). Early period inhibition (ES1) occurs with a latency of 10 -15 ms, late (ES2) - has a latency period of 25 - 55 ms. The degree of exteroceptive suppression in masticatory muscles is enhanced by homotopic nociceptive activity in trigeminal afferents, which is used clinically to quantify pain in patients with headaches and facial pain.

The exact mechanisms of development of ES1 and ES2 are unknown. ES1 is thought to be associated with oligosynaptic activation by trigeminal afferents of interneurons of the trigeminal complex nuclei, exerting an inhibitory effect on motoneurons of the masticatory muscles, while ES2 is mediated by a polysynaptic reflex arc involving neurons of the medullary part of the spinal trigeminal nucleus (Ongerboer de Visser et al., 1990). . At the same time, there is evidence that ES2 can be recorded during heterotopic pain stimulation, and electrical stimulation of the fingers reduces ES2 in the masticatory muscles (Kukushkin M.L. et al., 2003). This suggests that the mechanisms of ES2 development are more complex and are realized with the participation of supraspinal centers through the spinocorticospinal recurrent loop.

Method for recording somatosensory evoked potentials. Over the past two decades, somatosensory evoked potentials (SSEPs) have been widely used to measure clinical and experimental pain in humans. There is extensive research material on this issue, summarized in a number of review articles (Zenkov L.R., Ronkin M.A., 1991; Bromm B., 1985; Chen A.C.N., 1993). It is believed that the early SSEP components (N65-P120) reflect the intensity of the physical stimulus used to evoke pain, while the amplitude of the late SSEP components (N140-P300) correlates with the subjective perception of pain.

The idea that the amplitude of late SSEP components may reflect the subjective perception of pain was based on studies that showed a positive relationship between a decrease in the amplitude of the N140-P300 SSEP components and the administration of various analgesics. At the same time, the variability of the amplitude of late SSEP components is well known, which depends on a number of psychological factors such as attention, memory, emotional state(Kostandov E.A., Zakharova N.N., 1992), which can be significantly changed not only by analgesics, but also by the research procedure itself. In addition, recent publications on this problem (Syrovegin A.V. et al., 2000; Zaslansky R. et al., 1996) indicate a low connection between subjective pain perception and the amplitude of late SSEP components.

!!! The most reliable among electrophysiological methods for monitoring the magnitude of subjective pain sensation remains the nociceptive withdrawal reflex (NRE).

Functional mapping of neuronal activity of brain structures. IN lately V clinical practice methods of functional mapping of neuronal activity of brain structures in acute and chronic pain are increasingly being introduced (Coghill R.C., et al., 2000; Rainville P. et al., 2000). The most famous of them are: (1) positron emission tomography and method (2) functional magnetic resonance. All functional mapping methods are based on recording a local hemodynamic reaction in brain structures, which has a positive correlation with the electrical activity of neuron populations.

Using functional mapping methods, it is possible to visualize in three-dimensional spatial coordinates (millimeters in humans and micrometers in animals) changes in neuronal activity in response to presented nociceptive influences, which makes it possible to study the neurophysiological and neuropsychological mechanisms of pain.

The International Association for the Study of Pain defines it as follows: pain is an unpleasant sensory and emotional experience associated with existing or potential tissue damage. Pain is always subjective. Each person perceives it through experiences associated with receiving any damage in early years his life.
Pain is a difficult sensation, it is always unpleasant and therefore an emotional experience.

The perception of pain depends on the mood of the patient and the meaning of pain for him. The degree of pain experienced is a result of different pain thresholds. With a low pain threshold, a person feels even relatively mild pain, while other people, having a high pain threshold, perceive only strong pain sensations.

The pain threshold is reduced by discomfort, insomnia, fatigue, anxiety, fear, anger, sadness, depression, boredom, psychological isolation, social abandonment. The pain threshold is increased by sleep, relief of other symptoms, empathy, understanding, creativity, relaxation, anxiety reduction, painkillers.

Chronic pain syndrome accompanies almost all common forms malignant neoplasms and differs significantly from acute pain in the variety of manifestations due to the constancy and strength of the feeling of pain. Acute pain has different durations, but lasts no more than 6 months. It stops after healing and has a predictable ending. Chronic pain lasts longer
(more than 6 months). Manifestations of chronic pain syndrome can be reduced to such signs as sleep disturbance, lack of appetite, lack of joy in life, withdrawal into illness, personality changes, and fatigue. Manifestations of acute pain syndrome include patient activity, sweating, shortness of breath, and tachycardia.

Types of cancer pain and causes of their occurrence. There are two types of pain.
1. Nociceptive pain is caused by irritation of nerve endings.
There are two subtypes:
somatic - occurs with damage to bones and joints, spasm of skeletal muscles, damage to tendons and ligaments, skin germination, subcutaneous tissue;
visceral - in case of damage to the tissues of internal organs, overextension of hollow organs and capsules of parenchymal organs, damage serous membranes, hydrothorax, ascites,
constipation, intestinal obstruction, compression of blood and lymphatic vessels.
2. Neuropathic pain is caused by dysfunction of nerve endings.
It occurs when there is damage or overexcitation of peripheral nervous structures ( nerve trunks and plexuses), damage to the central nervous system(brain and spinal cord).

Pain assessment. When assessing pain, determine:
its localization;
intensity and duration (mild, moderate or severe, unbearable, prolonged pain);
character (dull, shooting, cramping, aching, tormenting, tiring);
factors contributing to its appearance and intensification (what reduces pain, what provokes it);
its presence in the anamnesis (how the patient suffered similar pain before).

Pain intensity assessed using two methods.
1. Subjective method- verbal rating scale. The intensity of pain is assessed by the patient based on the sensation:
0 points - no pain;
1 point - mild pain;
2 points - moderate (average) pain;
3 points - severe pain;
4 points - unbearable pain.
2. Visual analogue scale - a line, on the left end of which the absence of pain is noted (0%), on the right end - unbearable pain (100%). The patient marks on a scale the intensity of the symptoms he feels before and during therapy:
0% - no pain;
0 - 30% - mild pain (corresponds to 1 point on the verbal rating scale);
30 - 60% - moderate (2 points on the verbal rating scale);
60 - 9 0% - severe pain (3 points on the verbal rating scale);
90-100% - unbearable pain (4 points on the verbal rating scale).

They also use special rulers with a scale on which the strength of pain is assessed in points. The patient marks on the ruler the point corresponding to his sensation of pain. To assess the intensity of pain, a ruler with images of faces expressing expressions can be used. different emotions. The use of such rulers provides more objective information about the level of pain than the phrase: “I can’t stand the pain anymore, it hurts terribly.”

Drug therapy to relieve pain. plays a big role in carrying out drug therapy to eliminate pain. It is very important that she understands how a particular pain reliever works. In this case nurse together with the patient can carry out current assessment adequacy of pain relief. To conduct a final assessment of the effectiveness of analgesic therapy, objective criteria are required. Rulers and scales for determining pain intensity can serve as one of the criteria for assessing pain.

For cancer, the traditional three-step ladder of pharmacotherapy is used.

Used to relieve pain non-narcotic analgesics(aspirin, paracetamol, analgin, baralgin, diclofenac, ibuprofen), weak opiates (non-narcotic analgesics) (codeine, dionine, tramal), strong opiates (morphine hydrochloride, omnopon).

There is a certain danger that the patient will develop drug addiction. However, according to WHO, patients most often need pain relief with narcotic analgesics
terminal stage of the disease (preagonia, agony, clinical death), therefore the risk of developing addiction is not comparable in importance to the relief brought to the patient.

In addition to drug therapy carried out by a nurse as prescribed by a doctor, there are independent nursing interventions, aimed at relieving or reducing pain:
1) distraction;
2) changes in body position;
3) application of cold or heat;
4) patient education various techniques relaxation;
5) music therapy and art;
6) rubbing or lightly stroking the painful area;
7) distracting activities (occupational therapy).
This complex treatment chronic pain syndrome is used in hospice care, where the patient is taught how to live with the pain, not just how to "cure" it. People doomed to live experiencing chronic pain, need exactly this

Visual Analog Scale (VAS)

Using the VAS method, on a straight line 10 cm long, the patient notes the intensity of pain. The beginning of the line on the left corresponds to the absence of pain, the end of the segment on the right corresponds to unbearable pain. For convenience of quantitative processing, divisions are applied on the segment every centimeter. Numerical scales are more varied: on some, the intensity of pain is indicated by numbers from 0 to 10, on others - as a percentage from 0 to 100. The patient must indicate the intensity of pain, knowing that zero corresponds to the absence of pain, and the final number of the scale indicates the most severe pain, which the patient has ever experienced in his life.

The method of descriptive definitions is that the patient is offered definitions of pain: “mild”, “moderate”, “tolerable”, “strong” and “unbearable” (usually no more than 10 definitions). The patient must choose a definition and underline it. Comparative studies have shown that most patients prefer a descriptive scale, since the intensity of pain is expressed by adjectives, rather than abstract marks on a line, not numbers and percentages.

A multidimensional assessment of pain is possible using the McGill Pain Questionnaire, which in the Russian version consists of 78 descriptor words (words that define pain), combined into 20 subclasses (subscales), forming three main classes (scales): sensory, affective and evaluative . In each subclass, descriptors are arranged in increasing intensity; the subject must choose one of them that most matches his feelings. The patient is asked to describe the pain by selecting certain descriptors in any (not necessarily each) of the 20 subscales, but only one of the descriptors in the corresponding subscale. Data processing comes down to determining three indicators:

1. The number of selected descriptors index is the total number of selected words.
2. Rank pain index (RIPI) is the sum of the ordinal numbers of subdescriptors in a given subscale from top to bottom.
3. The intensity of pain is determined by counting words describing pain during the study period (at the time of presentation of the questionnaire).

Each indicator can be calculated for all scales entirely or separately for each scale.

Electrometric technique

Pain sensitivity thresholds are determined using the presentation of single electrical stimuli. The threshold of pain sensitivity is taken to be the parameters (amplitude) of the minimum electrical stimulus accompanied by the appearance of pain. Using this method allows you to quantification pain sensitivity thresholds, compare data on the diseased and healthy sides, etc. By measuring pain thresholds, a comparison of the sensation of pain in the so-called actual (in the area of ​​pain localization) and neutral zones has also been proposed. In the actual zone, pain thresholds are most often reduced.

Quality of life questionnaires

In order to assess the intensity of pain, its impact on life, and determine the effectiveness of the painkillers used, a study of the patient’s degree of vital activity is also carried out. There are several quality of life questionnaires. With their help, the degree of activity, performance, feeling of fatigue, mood changes, the effectiveness of the activity performed, emotionality (fear, anxiety, apathy, agitation, anger, frustration, etc.), the duration of these states, and their correlation with the degree of pain are assessed. All this allows us to indirectly judge the severity of pain. If a more thorough analysis of the emotional and personal sphere of patients is necessary, especially with chronic pain syndromes, special psychological testing is carried out: a multifaceted personality study (MIL), determination of the level of reactive and personal anxiety according to the Spielberger test, assessment of depression according to the Beck test, the Hamilton scale, etc. These studies are absolutely adequate, since the close relationship between the algic phenomenon, depression and anxiety has been proven.

Algometry

The algometry method consists of quantitative measurement of the subjective report of pain when presenting painful stimuli of increasing intensity. There are different types of algometers, including mechanical type is the most common. The researcher uses an algometer (a device in the form of a metal rod with a spring and a sensor) to press on certain points of the body. The pressure force is reflected by a digital indicator. When experiencing unbearable pain, the patient presses a special button and records a digital value corresponding to the force of mechanical pressure at which the pain occurred. Typically, many points are examined, which makes it possible to assess the zones of localization of maximum pain. Found this method greatest application in the study of myofascial pain of various localizations.

Trousseau-Bonsdorff test

To assess pain, the Trousseau-Bonsdorff test is also used: a pneumatic cuff is placed on the patient’s shoulder, maintaining its pressure above 10-15 mm Hg for 10 minutes. Art., then hyperventilation is carried out for 5 minutes: forced breathing (frequency 18-20 per minute). Ischemia and hyperventilation cause a complex of algic, sensory and autonomic manifestations. To assess pain, every minute during the test the patient marks the degree of pain experienced on a visual analogue scale.