Helen Laycock

Assessing pain objectively: the use of physiological markers.

Pain diagnosis and management would benefit from the development of objective markers of nociception and pain. Current research addressing this issue has focused on five main strategies, each with its own advantages and disadvantages. These encompass: (i) monitoring changes in the autonomic nervous system; (ii) biopotentials; (iii) neuroimaging; (iv) biological (bio‐) markers; and (v) composite algorithms. Although each strategy has shown areas of promise, there are currently no validated objective markers of nociception or pain that can be recommended for clinical use. This article introduces the most important developments in the field and highlights shortcomings, with the aim of allowing the reader to make informed decisions about what trends to watch in the future.

Pain Assessment in INTensive care (PAINT): an observational study of physician-documented pain assessment in 45 intensive care units in the United Kingdom.

Pain is a common and distressing symptom experienced by intensive care patients. Assessing pain in this environment is challenging, and published guidelines have been inconsistently implemented. The Pain Assessment in INTensive care (PAINT) study aimed to evaluate the frequency and type of physician pain assessments with respect to published guidelines. This observational service evaluation considered all pain and analgesia‐related entries in patients’ records over a 24‐h period, in 45 adult intensive care units (ICUs) in London and the South‐East of England. Data were collected from 750 patients, reflecting the practice of 362 physicians. Nearly two‐thirds of patients (n = 475, 64.5%, 95%CI 60.9–67.8%) received no physician‐documented pain assessment during the 24‐h study period. Just under one‐third (n = 215, 28.6%, 95%CI 25.5–32.0%) received no nursing‐documented pain assessment, and over one‐fifth (n = 159, 21.2%, 95%CI 19.2–23.4)% received neither a doctor nor a nursing pain assessment. Two of the 45 ICUs used validated behavioural pain assessment tools. The likelihood of receiving a physician pain assessment was affected by the following factors: the number of nursing assessments performed; whether the patient was admitted as a surgical patient; the presence of tracheal tube or tracheostomy; and the length of stay in ICU. Physician‐documented pain assessments in the majority of participating ICUs were infrequent and did not utilise recommended behavioural pain assessment tools. Further research to identify factors influencing physician pain assessment behaviour in ICU, such as human factors or cultural attitudes, is urgently needed.

Pain in Intensive Care: A Personalised Healthcare Approach

For patients admitted to intensive care, pain is a common experience with potentially significant consequences. Pain management needs to evolve from the traditional ‘one-size-fits-all’ plan to a more personalised approach. This can be achieved by appreciating the numerous potential causes of pain, using appropriate assessment tools, utilising a range of potential treatment options and addressing the challenges associated with pain management in this heterogeneous population. At this point a truly multimodal, multidisciplinary management plan can be implemented, aimed at improving pain control and ultimately patient outcomes.

The case for invasive placebo – is the devil in the detail?

In this issue of Anaesthesia we publish a paper by Kumar et al. evaluating the effect of pre-operative stellate ganglion block on postoperative tramadol consumption following surgery to fixate upper limb fracture [1]. This research study was prompted by the 2011 case series from McDonnell et al. that showed a marked benefit of stellate ganglion block performed for similar indications with respect to postoperative pain scores and analgesic requirements [2]. Two editorials accompanied McDonnell et al.’s paper; one discussed the potential for modulation of acute somatic pain by the autonomic nervous system [3], and the other called for robust substantiation of the findings before such an approach was incorporated into routine clinical practice [4]. Kumar et al. have now performed a randomised, doubleblind, placebo-controlled study to address the latter point. Subjects received a 3-ml stellate ganglion injection of either lidocaine 2% or saline before general anaesthesia and surgery. The authors report a statistically significant and clinically relevant reduction in tramadol consumption, administered via patientcontrolled analgesia, over the first 24 h postoperatively. There are two conventional ways of assessing the benefit of an analgesic intervention: measuring pain scores and/or recording analgesic usage (preferably with a patient-controlled analgesia system rather than administered if and when requested). Whilst pain scores are commonly used as a research tool, a statistically significant difference in pain scores may translate poorly to an actual clinical benefit for the patient. Furthermore, pain scores are also hampered by intraand inter-individual variation in scoring, making a change in median pain scores across a group difficult to interpret. In contrast, use of analgesics can be used as a surrogate marker for pain, if one assumes that the patient is ‘titrating’ the analgesic dose to provide an acceptable level of analgesia. Whilst this is not a direct evaluation of subjective pain, it reflects the patient experience, as the reduced use of analgesic medication can be thought to represent a reduction in the pain experienced. In addition, it addresses an important non-specific aspect of managing pain, also inherent in the concept of multi-modal analgesia: that of a reduction in analgesic doses in order to reduce side-effects. The aim of the optimal analgesic package is to get the best analgesia for the least ‘cost’, if we consider cost to include not just the financial tariff but also complexity and time, side-effects and risks. Therefore Kumar et al.’s study aims to address two questions. The first is the usefulness of stellate ganglion block before upper limb surgery in reducing postoperative pain as reflected by a reduction in selfadministered analgesic requirements. The second, and possibly more important question, is its exploration of the relationship between the autonomic nervous system, nociception and acute pain.

The value of pupillary dilation in pre-emptive analgesia: is there more to this than meets the eye?

The pupillary dilatation reflex may present an objective method of predicting whether sedated patients require additional analgesia for painful procedures. Behavioural pain assessment tools identify pain only once it has occurred and are unable to guide pre-emptive management. The pupillary dilatation reflex response to a tetanic stimulus has been utilised to assess analgesic requirements in patients under anaesthesia and for those with postoperative pain. This tool appears promising to assess pain in the critically ill; however, a number of questions remain unanswered regarding the influence of sedation on this response. These questions require further exploration before the pupillary dilatation reflex can be widely adopted into clinical practice.

Between evidence and commerce - the case of sufentanil sublingual tablet systems

As a specialist in a field of medicine, occasionally one is obliged to read, and quite often re-read, about aspects of your practise. In this instance, writing this editorial coincided with refreshing our knowledge regarding the literature on gabapentin. Therefore, coincidentally, we came across an article by Steinman et al. that reported how ‘cleverly’ industry promoted the anticonvulsant and antineuropathic drug gabapentin in the 1990s [1]. For their article, Steinman et al. reviewed publicly available court documents from the USA and thus identified three main strategies industry employed to promote gabapentin. The first involved continuing medical educational activities targeting a wide audience, for instance organising local talks and lectures as well as meetings and conferences. The second approach, advisory boards and consultant meetings, was directed at opinion leaders and high-rate anticonvulsant prescribers. Meetings were often held at luxury hotels and participants frequently received honoraria and travel reimbursements. Finally, Steinman et al. found even research and publication strategies ‘served as key elements in the marketing for the drug [gabapentin]’. Original articles, for instance, were not only used to gain US Food and Drug Administration (FDA) approval, but also as tools to ‘disseminate information as widely as possible’. Review articles and letters to the editor had the same purpose. Often, medical education companies were employed to guide or even directly prepare manuscripts (‘ghost-writing’), and to choose ‘suitable authors’. ‘Suitable authors’ usually already had a commercial relationship with industry and/or were subsequently paid to participate in the publication process. Also, for some articles, sponsorship was not disclosed. Steinman et al. concluded that involving physicians in research and publication helped industry to engage opinion leaders, reward customers and influence prescribing. Reflecting on Steinman’s article and because of the recent, seemingly omnipresent, advertisements for the sufentanil sublingual tablet system (SSTS), we thought it prudent to gather more information about how the data presented in van de Donk et al.’s review, published in this edition of the journal, were generated, whether they might be in any way biased, and whether any particular marketing strategy, that might resemble the process Steinman described, was apparent relating to SSTS [2].

Pain in Intensive Care

Pain, ‘an unpleasant sensory and emotional experience associated with actual or potential tissue damage’ [1], is the most common symptom reported by patients in the intensive care unit (ICU). However, pain is frequently underrecognised and ineffectively managed in the critical care setting [2, 3].

Objective Assessment of Acute Pain

Assessing acute pain in those unable to communicate is challenging yet essential. Objective assessment tools utilizing measures derived from autonomic changes alone or in combination appear to represent a potential solution to this difficult aspect of pain management.

Pain assessment in intensive care: who puts pen to paper?

Pain is common in intensive care units (ICUs)[1]. Regular pain assessment can improve patient satisfaction and clinical outcomes. It is commonly performed by nurses [2], yet physician-led assessment can improve analgesic management. Using pain documentation as a surrogate for assessment, a review showed physiological parameters i.e. cardiovascular assessment, were more frequently documented by doctors than pain in critically ill patients [3].

The potential use of biomarkers and new diagnostic tools in the management of acute pain

187 ISSN 1758-1869 10.2217/PMT.12.11