Variability of sensory threshold determination in clinical use.

The variability of perception threshold determination for vibration, tactile stimuli and thermal stimuli, with instruments intended for clinical use, was studied in 13 healthy subjects and 27 patients with chronic polyneuropathy. Normal thresholds for tactile and thermal stimuli were determined in 51 healthy subjects. Determinations were made for vibration on hand, lower leg and foot, for touch on pulp of forefinger and great toe and for temperature on hand and foot. Normal thresholds for both tactile and thermal stimuli were age-dependent. Short-term variation, with intervals of some minutes between determinations, remained within 8-18% change from first value. Long-term variation, with intervals of days to some weeks, was pronounced for all types of threshold, with extremes of -90% and +256% change from first determination in 3 or 4 subsequent determinations. Variation was most marked for tactile stimuli and smallest for vibration, but magnitude and pattern of variation was similar for all sensory modalities and for both patients and healthy subjects. Confidence intervals, derived from analysis of variance, showed than as an average a change of less than -60% or greater than +150% from the initial value was needed to ascertain with 95% probability that a subsequent value will reflect a true change of sensory threshold. Basing every threshold value on 2 or more measurements per occasion will reduce the confidence interval. The main cause of variability seems to be central processing mechanisms, i.e. the psychological variability. With proper attention to the variability, sensory threshold determinations should still be a valuable aid in clinical practice and clinical research.

Quantitative sensory testing in fibromyalgia patients and in healthy subjects: identification of subgroups.

OBJECTIVE: To determine perception and pain thresholds in patients with fibromyalgia syndrome and in healthy controls, and to investigate whether patients with fibromyalgia syndrome can be grouped with respect to thermal hyperalgesia and whether these subgroups differ from healthy controls and in clinical appearance. DESIGN: The authors conducted a quasi-experimental clinical study. SUBJECTS: Twenty-nine women patients with fibromyalgia syndrome and 21 healthy pain-free age-matched women participated in the study. METHODS: Quantitative sensory testing using a Thermotest instrument was performed on the dorsum of the left hand. Sleep and pain intensity were rated using visual analog scales. RESULTS: Cold and heat pain but not perception thresholds differed significantly between patients with fibromyalgia syndrome and healthy subjects. Based on thermal pain thresholds, two subgroups could be identified in fibromyalgia syndrome using cluster analysis. CONCLUSION: Patients with fibromyalgia syndrome were subgrouped by quantitative sensory testing (i.e., thermal pain thresholds). Subgroups show clinical differences in pain intensities, number of tender points, and sleep quality. Cold pain threshold was especially linked to these clinical aspects.

Effects of regional intravenous guanethidine block in posttraumatic cold intolerance in hand amputees.

In twenty-four patients with intolerance to cold after partial or complete finger amputations, lower skin temperature together with cold and vibration allodynia (allodynia = pain due to a non-noxious stimulus to neural skin) were found in the cold intolerant area compared with the corresponding area in the uninjured hand. When treated with regional intravenous guanethidine block nine patients became free from symptoms for up to twelve weeks, which is longer than would be expected from the duration of the known pharmacological effects of guanethidine. The patients had several features in common with reflex sympathetic dystrophies, and we suggest that neurogenic rather than vascular disturbances are mainly involved in the post-traumatic cold intolerance syndrome.

Importance of dietary advice, nutritional supplements and compliance for maintaining body weight and body fat after hip fracture.

OBJECTIVE: Poor nutritional status amongst elderly individuals with hip fractures is well documented. Studies have suggested that 30-50 % of patients admitted to orthopaedic departments suffer from protein-energy malnutrition (PEM). DESIGN: An 6 month intervention study. SETTING: The study was conducted in Sweden between February 2005 and October 2006. PARTICIPANTS: Elderly patients with hip fractures (n=32). METHODS: Evaluation of compliance with individual nutritional support and whether body weight and body fat (BF) could be maintained after six months. Evaluation of possible effects of nutritional supplements and dietary advice after hip fracture on BMI, BF, and Mini Nutritional Assessment (MNA). RESULTS: Overall compliance with supplement intake was 73%. After six months, BMI was unchanged. Women's BF had decreased (P < 0.01), although the mean calorie intake with nutritional support was 34 calories per kg body weight/day. Three groups could be identified: one group with increased body weight and BF, one with loss of body weight and BF, and one with increased body weight together with increased TBW and loss of BF. PARTICIPANTS who consumed 0-1 supplements daily lost more weight than those who consumed 2 supplements daily. There was a positive difference (p= < 0.001) for women between MNA values at baseline and after six months. CONCLUSION: In the present study compliance was satisfactory at the group level, and the energy and protein intake increased significantly. BMI was unchanged during the 6 months period. However, the women lost BF during the study period of with some had increasing total body water (TBW). MNA values for women changed in a positive direction.

Assessment and prevention of shivering in patients with severe cerebral injury. A pilot study.

Low body temperature is induced by surface cooling to reduce metabolic demands in patients with severe cerebral injury. Shivering, which increases energy expenditure, is a common effect of surface cooling. The aim of this pilot study was to investigate whether increased gradient between the set point and peripheral temperature is related to shivering and whether modifying the loss of body heat during surface cooling decreases the frequency of shivering. Seven cerebrally injured patients at a neurosurgical ICU were studied. Shivering, surface cooling and the temperature gradient measured as the tympanic and the tip toe temperatures were registered every 30 min. Shivering was assessed at three levels: no shivering, mild shivering and severe shivering. In four patients the arms and legs were covered with a cotton cloth for part of the observation time to modify the rate of heat loss. The temperature measurements were repeated in each patient between 13 and 42 times. Four patients out of seven shivered. There was a significant association between increased temperature gradient and shivering (P < 0.01). Modifying the rate of heat loss decreased the temperature gradient (P < 0.001). By simultaneously measuring the tympanic and tip toe temperatures it may be possible to detect shivering earlier and decrease its frequency by modifying the loss of body heat during surface cooling.

Effect of education on evidence-based care and handling of peripheral intravenous lines.

Deficient routines in use, care, handling and documentation of peripheral intravenous vein cannulae (PIV) have previously been reported, and complications have been noted in 50-75% of the patients. The aim of the study was to examine whether specially trained nurses change their actions to decrease complications when using cannulae. The study included 36 nurses assigned to experimental and control groups. The experimental group followed an education programme explaining how to use and take care of a PIV. To evaluate the intervention document analysis, observations and patient interviews were performed in 99 patients with 172 PIVs in situ for less than 24 h. After the education programme, fewer complications, more carefully performed care and handling, and better documentation and information were found in the experimental group. Nurses in the control group followed current routines, which resulted in a greater degree of complications. Education in evidence-based care and handling gives nurses the opportunity to improve their ability to use theoretical knowledge in clinical problems.

Multiunit neural responses to strong finger pulp vibration. II. Comparison with tactile sensory thresholds.

In a companion microneurographic study (Schmidt et al. 1990) maximal multiunit sensory responses to finger pulp vibration were compared with maximal responses evoked by electrical stimulation of the digital nerve. It was found that the MR/ER ratio, i.e. the ratio between the magnitudes of the responses to mechanical and electrical stimulation, decreased with increasing age. The shape of this age-related decline in the ratio corresponded well with the decrease in the number of Meissner corpuscles found in histological studies. In the present study the tactile sensory detection thresholds were measured in the same subjects that participated in the companion study and the relationship between these thresholds and the MR/ER ratios was examined. The tactile sensory detection threshold increased with age. A weak negative correlation was found between the threshold and the ratio. However, after compensation for common age-mediated effects, this negative correlation disappeared. Thus, the results indicate that measurement of tactile sensory detection thresholds and determination of MR/ER ratios may complement each other, giving an indication of different types of derangement of the mechanoreceptive system.

Stress coping strategies in thermal pain sensitive and insensitive healthy subjects.

The aim of this study was to investigate stress coping strategies used in relation to heat and cold pain thresholds in healthy subjects. After using the Jalowiec Coping Scale, cold and heat pain thresholds were examined using the Quantitative Somatosensory Test in 47 healthy subjects. The participants were separated into thermal pain sensitive and insensitive groups, based on thermal pain perception. The results showed that subjects sensitive to thermal pain tended to adopt an emotive stress coping style significantly more commonly than the insensitive subjects. Furthermore, women displayed a marked preference for this style compared to men. The conclusion is that emotional stress coping did play a role in the perception of thermal pain in this group of healthy subjects and that clinical nursing interventions need to focus on the relationship between emotion and coping.

Nociceptor modulated central sensitization causes mechanical hyperalgesia in acute chemogenic and chronic neuropathic pain.

Brush-evoked pain (mechanical allodynia, dynamic mechanical hyperalgesia) is a hallmark of neuropathic and inflammatory pain states. Here we have examined the neural mechanisms that induce and maintain this component of mechanical hyperalgesia. The principle finding of these experiments is that the severity of brush-evoked pain correlates with the intensity of background pain in patients suffering from chronic painful neuropathies and in normal subjects with acute experimental chemogenic pain. In experiments on nine normal subjects topical application of mustard oil for 5 min evoked strong burning pain and hyperalgesia to light mechanical stimuli. Differential nerve blocks (by compression of the superficial radial nerve) revealed that the brush-evoked pain was transmitted by A beta-fibres, which normally encode non-painful tactile sensations, while the burning pain was signalled by C-fibres. Psychophysical measurements showed that mustard oil treatment resulted in a pronounced sensitization of nociceptors to heat so that subsequent innocuous changes of skin temperature from 35 to 40 degrees C resulted in a proportional increase of burning background pain. Changes in the magnitude of ongoing burning pain were closely correlated (r = 0.81) to the intensity of brush-evoked pain. While conduction block of A-fibres eliminated only touch-evoked pain, blockade of C-fibre excitation instantaneously abolished both ongoing and touch-evoked pain. In nine patients with chronic neuralgia (15 years mean duration) ongoing and brush-evoked pain were examined. In six patients, differential block of A beta-fibres eliminated touch-evoked pain, but ongoing pain persisted when only C-fibres were conducting. Complete relief of both ongoing and stimulus-induced pain was obtained in two patients with intravenous regional guanethedine block and in two other individuals by local anaesthetic blocks of nerves supplying the symptomatic skin, indicating that input from primary afferents was necessary for the maintenance of the pains and that ongoing pain was not self-perpetuated by central mechanisms alone. Quantitative sensory tests revealed heat hyperalgesia in four patients. In those individuals, an increase of skin temperature produced a graded increase of their ongoing pain which was closely correlated (r = 0.94) with the level of brush-evoked pain. In the remaining five patients there was no heat hyperalgesia and consequently no aggravation of pain by increases of skin temperature. Nevertheless when the intensity of the background pain fluctuated spontaneously there were also parallel changes (r = 0.88) of the severity of brush-evoked pain.(ABSTRACT TRUNCATED AT 400 WORDS)

Side effects after surgical treatment of snoring.

In a questionnaire study detailed side effects after snoring surgery were examined in 415 individuals 2-8 years after surgery. Three years later a new questionnaire was answered by those with side effects affecting taste, smell and voice (n = 74). At the first follow-up 255 had side effects of globus, regurgitation, taste, smell and voice. The globus was the most common (40%). In all spheres except the globus, a significant improvement was seen 3 years later. However, pharyngeal dryness and phlegm had a reported frequency of nearly 60%. No significant differences were seen between the uvulopalatopharyngoplasty and laser uvulopalatoplasty methods. Taste disturbances might be due to surgical damage to the nerves or oral dryness. The olfactory impairment present in 7 patients still needs to be explained.

Patients' and cohabitants' reports on snoring and daytime sleepiness, 1-8 years after surgical treatment of snoring.

A follow-up study was performed with the aim to evaluate all individuals surgically treated by the uvulopalatopharyngoplasty (UPPP) or laser uvulopalatoplasty (LUPP) method from a whole county in Sweden, 1-8 years after surgery, by assessing snoring occurrence and daytime sleepiness, as experienced by the patients and their cohabitants. Questionnaires were mailed to all operated people (n = 457) and were returned by 91% (346 men, 69 women) preoperatively diagnosed as habitual snorers (n = 255), cases of obstructive sleep apnea syndrome (n = 110) and unspecified snorers (n = 48). In addition 345 bedpartners participated. For outcome of surgery, no significant differences in diagnoses or sex were found. Improvement in snoring occurrence was reported by 89.6% of the patients, confirmed by 92% of the cohabitants (r = 0.84, p < 0.01). The remaining snoring occurrence was significantly dependent on the surgical method and the time after operation. Excessive daytime sleepiness (EDS) was experienced by 73.3% of the patients compared to 67% reported by the cohabitants. Of 415 patients operated on, 18% were free from snoring and 25% were free from EDS. Individuals with a shorter time since surgery reported less snoring. The UPPP method gave a significantly better result than LUPP for the symptom 'snoring'.

Multiunit neural responses to strong finger pulp vibration. I. Relationship to age.

The effect of age on mechanoreceptive function in the distal part of the fingers was studied in 12 healthy subjects aged 18-64 years. A recording microelectrode was inserted into a sensory fascicle of the median nerve at the wrist. Multiunit mechanoreceptor activity was recorded from the fascicular field, which is typically restricted to the ulnar or radial half of one finger, corresponding to the innervation zone of one digital nerve. Strong standardized vibration (40 Hz) was applied to the finger pulp, with the amplitude of the vibration pulses high enough to induce maximal neural impulse volleys. With the same microelectrode recording position, maximal neural impulse volleys were also induced by electrical pulses applied to the ventral digital nerve supplying the finger pulp. In each subject, the areas of the mechanically and the electrically induced responses were measured (after integration and averaging) and the ratio of mechanically to electrically induced responses (MR/ER) was determined. The MR/ER ratio decreased with increasing age of the subject. This finding was considered to indicate that it is the peripheral parts of the sensory units, involved in the mechanoelectrical transfer functions, that exhibit the most pronounced degenerative changes during the ageing process. This is in line with previous histological findings of pronounced age-related degeneration of Meissner corpuscles and other mechanoreceptive end organs in the finger pulps.

Peripheral intravenous lines: time in situ related to complications.

The purpose of this study is to examine the relationship between time in situ and the frequency of thrombophlebitis. Nurses' care and handling when using a peripheral intravenous (p.i.v.) line was also studied. The methods used were observation, interview, and document analysis after intervention, with respect to cannula time in situ. The study included 120 patients divided in two groups: (1) experimental, time in situ less than or equal to 24 hours, and (2) control, using current/daily routines from the wards. The frequency of thrombophlebitis after a p.i.v. was inserted was significantly higher and showed more troublesome and prolonged picture complications in the control group than in the experimental group. Care and handling suffered with increased number of days in situ. The nurses' documentation of inserted or removed cannula was incomplete in most cases, and notices about the insertion area were nearly nonexistent. It was determined that a short time in situ--when using a p.i.v.--is an important factor in preventing complications.