A.J.M. van Wijck

Effect of chronic nonmalignant pain on highway driving performance

Abstract Most pain patients are treated in an outpatient setting and are engaged in daily activities including driving. Since several studies showed that cognitive functioning may be impaired in chronic nonmalignant pain, the question arises whether or not chronic nonmalignant pain affects driving performance. Therefore, the objective of the present study was to determine the effects of chronic nonmalignant pain on actual highway driving performance during normal traffic. Fourteen patients with chronic nonmalignant pain and 14 healthy controls, matched on age, educational level, and driving experience, participated in the study. Participants performed a standardized on‐the‐road driving test during normal traffic, on a primary highway. The primary parameter of the driving test is the Standard Deviation of Lateral Position (SDLP). In addition, driving‐related skills (tracking, divided attention, and memory) were examined in the laboratory. Subjective assessments, such as pain intensity, and subjective driving quality, were rated on visual analogue scales. The results demonstrated that a subset of chronic nonmalignant pain patients had SDLPs that were higher than the matched healthy controls, indicating worse highway driving performance. Overall, there was a statistically significant difference in highway driving performance between the groups. Further, chronic nonmalignant pain patients rated their subjective driving quality to be normal, although their ratings were significantly lower than those of the healthy controls. No significant effects were found on the laboratory tests.

Processing capacity in chronic pain patients: A visual event-related potentials study

Abstract Chronic pain may impair performance on attentional processing capacity tasks. In the present study, event‐related potentials were recorded to examine whether pain patients show performance decrements on attentional processing capacity tasks due to shared resources by pain and attention or, alternatively, due to deficits in allocating attentional resources during pain. Fourteen chronic pain patients and thirty age and education matched healthy controls were investigated. An attentional capacity probe task was used in which the difficulty level was manipulated, resulting in an easy and a difficult condition, while task‐irrelevant visual probes were presented. These probe‐elicited P3 amplitudes were assumed to provide the most pure estimate of processing capacity since they are relatively free from target‐related processes. Event‐related potentials were recorded from the midline electrodes Fz, Cz, Pz, and Oz. For the behavioral measures, it was found that pain patients maintained a different speed‐accuracy tradeoff. Pain patients showed faster reaction time responses and higher error rates compared to controls. No significant differences were found between pain patients and controls on the primary task. Pain patients differed from controls with respect to amplitudes elicited by task‐irrelevant probe stimuli. For healthy controls, the expected decreased amplitude was found for probe stimuli in the difficult compared to the easy task. In contrast, the pain patients did not show decreased probe amplitudes with increasing task load. The data may imply that allocation of attentional resources is deficient in pain patients, instead of attentional capacity.

No beneficial effect of intrathecal methylprednisolone acetate in postherpetic neuralgia patients

High efficacy of intrathecal methylprednisolone acetate (MPA) with lidocaine has been reported in a large patient group suffering from intractable postherpetic neuralgia (PHN). Because the treatment effect was never independently confirmed and there are ongoing safety concerns, intrathecal MPA did not become standard care for intractable PHN. We report the results of a replication trial assessing pain relief and spinal cytokine/chemokine levels in PHN patients.

The Impact of Chronic Pain Patients' Psychotropic Drug Knowledge and Warning Labels on the Decision Whether to Drive a Car or Not

Objective. The attitudes of patients towards driving a car while taking medication with psychotropic side effects is unclear. A growing number of patients use these psychotropic medicines on a daily basis, and this may interfere with their ability to drive a car. Methods. By means of a survey, we examined attitudes towards driving while using psychotropic medicinal drugs and the effect of warning labels on the decision whether to drive a car or not in patients with chronic pain. Results. Fifty-eight of 100 patients possessing a drivers license used psychotropic medication. Despite warning labels affixed on the packages that these drugs might impair driving ability, the majority (71%) of these patients continued driving a car. A point of concern is that 40% of these patients reported not to be more cautious in traffic after taking psychotropic drugs. Conclusion. The results of this survey indicate that drug warning labels applied by Dutch pharmacies do not significantly change attitudes towards driving a car in patients taking medicinal drugs with psychotropic side effects. Future road-safety campaigns should pay more attention to the impairing effects of psychotropic drugs on driving.

Pain in patients with chronic idiopathic axonal polyneuropathy

Background/Aims: Pain in patients with chronic idiopathic axonal polyneuropathy (CIAP) has never been studied in detail. The aim of the study was to investigate the pain experienced by patients with CIAP, and to determine whether pain is associated with health-related quality of life (HRQoL). Methods: The McGill Pain Questionnaire (MPQ) and the RAND-36 were used in a cross-sectional study. Results: Sixty-three of 91 patients with CIAP reported experiencing pain, describing it as nagging (56%) and annoying (52%). Of these patients, 27 were classified in a subgroup with neuropathic pain (median VAS = 33 mm), 25 in a subgroup with non-neuropathic pain (median VAS = 34 mm), and 11 in a mixed-pain subgroup (median VAS = 25 mm). Non-neuropathic pain was as common and as painful as neuropathic pain. Pain was strongly associated with the physical functioning domain of the RAND-36 in patients in the mixed pain subgroup (r = –0.71, p < 0.05). Conclusion: Neuropathic and non-neuropathic pain syndromes should be distinguished in patients with CIAP who experience pain, to enable appropriate tailoring of treatment.

Design issues for studies into prevention of chronic pain: lessons from post-herpetic neuralgia.

For many years it has been suggested that the routine pre-preparation of succinylcholine prior to anaesthesia is a necessary part of safe anaesthetic practice. This view has been supported by statements such as ‘this is a powerful reason to always have succinylcholine drawn up before any anaesthetic’ [1] when considering the treatment of laryngospasm. It is possible, however, that such practice is less relevant today following the development of more ‘airway-friendly’ drugs (e.g. propofol and sevoflurane), advances in fibreoptic intubating techniques and improved monitoring combined with the well-recognised side-effects of succinylcholine. Important unwanted side effects of succinylcholine include severe bradycardia (particularly in infants not pre-treated with an anticholinergic), prolonged apnoea in patients with atypical plasma cholinesterase, malignant hyperthermia [2] and allergic reactions. The incidence of anaphylaxis to neuromuscular blocking agents has been estimated at 1 in 6500 anaesthetics [3] and, whilst reports vary as to the most common agent involved, succinylcholine is a major contributor [3,4]. In addition, the use of succinylcholine in paediatric anaesthesia has been questioned, following several case reports of cardiac arrest after its use in apparently healthy children who were later shown to have occult neuromuscular disease [5–7]. Is there a trend among anaesthetists to move away from routine pre-preparation of succinylcholine? We conducted a survey of current practice in the West Midlands region recently, which indicated that only 26.8% of anaesthetists routinely pre-prepare succinylcholine, although a response rate of just 44% makes it difficult to draw any definite conclusions. The returns indicated that the more senior and experienced the anaesthetist, the less likely they are to preprepare succinylcholine on a routine basis; this may partly reflect the more elective nature of their work, as well as greater expertise with the management of the type of airway problems that may be considered, by some, an indication for the urgent use of succinylcholine. Why should some anaesthetists wish to have pre-prepared succinylcholine readily available? The advantage of routine pre-preparation of succinylcholine is the reduction in ‘decision to delivery’ time, which is of relevance for the singlehanded anaesthetist, those working in an unfamiliar environment, or when pre-preparation and dilution are considered necessary (e.g. in paediatric practice), thus ensuring that the anaesthetist is not distracted when full attention to the clinical situation may be most needed. Whether it is safer to draw up succinylcholine routinely unless intended for immediate use is, however, debatable and the benefit must be weighed against the risks. A major disadvantage of routine prepreparation is the risk of accidental injection (wrong drug, wrong time and ⁄ or wrong patient, with the potential risk of paralysing an awake patient). A postal survey in New Zealand showed that 26.5% of practising anaesthetists had experienced ‘syringe swap’ or ‘wrong drug’ errors related to predrawn emergency drugs, while delay in drawing up drugs in an emergency was reported by 37% of respondents [8]. Furthermore, a Canadian survey reported that 85% of anaesthetists surveyed had experienced at least one drug error or ‘near miss’; ‘syringe swaps’ (70.4%), failure to read the label (62.9%) and the misidentification of the drug ampoule or vial (46.8%) were common contributing factors [9]. The true cost of a dose of succinylcholine equals the acquisition cost of the drug plus the cost of treating complications following its use (should they occur) plus the cost of adverse outcomes; this is estimated to be more than 20 times the acquisition cost [10]. The wastage of pre-prepared, but unused, drugs is especially relevant in developing countries because of the severe limitations on funding available for healthcare – this is particularly so for the provision of anaesthetic services. The availability of pre-filled syringes avoids the unnecessary wastage but still may involve delay resulting from the time taken to calculate the correct dose, particularly in paediatric practice. Failure to ventilate, specifically as a result of acute upper airway problems, continues to be a common but avoidable cause of cardiac arrest [11], whilst laryngospasm is the most common cause of upper airway obstruction after tracheal extubation [12]. It is probable that severe laryngospasm has been the most common indication for the unplanned use of succinylcholine; if the need for its pre-preparation is questioned, what alternative strategies are available for managing severe laryngospasm? Causes of laryngospasm include inadequate depth of anaesthesia at the time of surgical stimulation, airway manoeuvres including insertion or removal of airway devices, and movement of the head and neck whilst airway devices are still in situ in an inadequately anaesthetised patient. Other risk factors include intercurrent upper respiratory tract infection, extubation of a soiled airway, thyroid surgery and hypocalcaemia [13]. Management options for peri-operative laryngospasm include: the removal of the stimulus precipitating the laryngospasm; continuous positive airway pressure (CPAP) with 100% O2 via face mask (with or without positive pressure ventilation); jaw thrust with pressure in the ‘laryngospasm notch’ (an area behind the lobule of the pinna of each ear bounded anteriorly by the ascending ramus of the mandible adjacent to the condyle, posteriorly by the mastoid process of the temporal bone and Anaesthesia, 2004, 59, pages 211–215 .....................................................................................................................................................................................................................

776 ‘BEARABLE PAIN' IS NOT THE SAME FOR MEN AND WOMEN

Background and aims: In guidelines for postoperative pain management specific Numeric Rating Scale (NRS) cut-off points (≥ 3 or 4) have been identified to indicate the need for pharmacological treatment. In clinical practice, however, patients with NRS ratings 3 or more, often refuse medication. Therefore we studied the relation between the postoperative pain score on Numeric Rating Scale (an 11 point scale) and Verbal Rating Scale (VRS). We used an adjusted VRS consisting five expressions: no pain, a little pain, painful but bearable, considerable pain and terrible pain. The results showed that patients often considered intermediate NRS scores (5-7) as ‘bearable pain’1,2.Other studies have suggested that gender is of influence in the level of pain reported by patients3. We further study this hypothesis by examining how men and women relate NRS to VRS ‘painful, but bearable’.