Bailliere's clinical anaesthesiology最新文献

Non-opioids are first-line drugs for long-term pain therapy. They are effective and have a low incidence of side-effects. There are differences between non-opioids, allowing for differential indications in order to improve efficacy as well as safety. While patients with low back pain and osteoarthritis are often treated well using pure analgesics, patients with rheumatoid arthritis, and in particular those with ankylosing spondylitis, require the most potent anti-inflammatory drugs. Patients with cancer pain of moderate-to-severe intensity also benefit from them, but this is limited by the progression of the disease and the ceiling effect of non-steroidal anti-inflammatory drugs (NSAIDs). Regular endoscopic investigation of the upper gastro-intestinal tract should be considered for the prevention of fatal side-effects in patients at risk. The choice of drugs for treatment must be based on outcome studies of high quality. According to the selection of studies presented, a few drugs can be ranked, those with highest safety first: ibuprofen, tenidap, fenbufen, aceclofenac, indomethacin, ketorolac, diclofenac, tenoxicam, piroxicam and ASA.

A clinically relevant benefit resulting from prophylactic analgesia has so far been observed in only a very few studies. In general, these effects have been limited to the immediate post-operative period. The most promising results have been observed with spinal opioids. However, several investigations on the effect of preventive analgesic measures have been performed in patients with lower limb amputation. In these studies, pre- and post-operative epidural analgesia with local anaesthetics and opioids, beginning at least 2 days preoperatively and continued for at least 3 days post-operatively, reduced the incidence of phantom limb pain by 50–90%. If epidural catheter placement is not possible, for example owing to systemic infection or trauma, 3 days continuous peripheral nerve block with 6–10 ml per hour bupivacaine 0.5% at the sciatic or posterior tibial nerve may be an alternative, provided that effective nerve block is established prior to amputation.

Chronic pain is difficult to treat successfully. The lack of satisfactory outcome from the traditional medical, pharmacological and surgical approaches was an impetus to the development of specialty treatment facilities—multidisciplinary pain centers (MPCs). With health-care costs continuing to rise, the clinical efficacy and cost-effectiveness of MPCs have recently been challenged. In this chapter, it is argued that the efficacy of treatment for chronic pain should be evaluated on multiple criteria: reduction in pain, use of analgesic medication and utilization of the health-care services. Increases in functional activity, return to work and closure of disability claims should also be considered. The published results for MPCs are reviewed in comparison with alternative treatment methods. The results suggest that MPCs are more effective than alternative monodisciplinary approaches. Furthermore, it is concluded that MPCs can produce saving of billions of dollars in terms of health-care expenditure and indemnity costs.

Since the emergence of locoregional anaesthesia, nerve blocks with local anaesthetic or neurolytic agents have been used in chronic pain patients for diagnostic and therapeutic purposes.

A critical evaluation of this type of intervention has only begun during the past 10 years. In the literature, few clinical reports on nerve blockade have withstood criticism. A scientific basis for legitimating the daily use of nerve blocks in our clinical practice is missing.

This has led not only to controversy and discussion, but also to a renewed interest and a more scientific approach towards nerve blockade. Other invasive techniques have also emerged, such as radiofrequency lesioning and dorsal column stimulation; they have partially replaced the older neurolytic or destructive techniques.

With the help of several co-authors, this chapter outlines the points of this evolution.

The majority of patients with cancer pain need therapy including strong opioids, and patients with non-cancer pain may also benefit from strong opioid medication. This review analyses the efficacy of an opioid therapy comparing different substances and routes of administration. It is shown how, with an adequate choice of medication and mode of administration, opioid therapy may have a low incidence of side-effects and provide a high level of safety. Today, oral medication with sustained-release morphine at a given interval is regarded as the ‘golden standard’ for chronic pain therapy. An alternative may be transdermal fentanyl, but further controlled trials are necessary.

The context of the current outcome movement is discussed and different outcome measures are presented. One central issue is analysing the advantages and drawbacks of the various methods of assessing pain. However, relying solely on pain as an outcome measure is mostly inadequate in chronic conditions: the report of pain itself is already influenced by psychosocial factors, which, in turn, are themselves substantially related to outcome and are therefore considered to be important outcome variables. The impact of pain on psychological as well as work-related factors is emphasized, and appropriate ways of measuring improvement, and distinguishing statistically from clinically important change, are presented. Basic principles to develop and use good outcome assessment need to be observed.

In hypertensive heart disease, coronary vasodilatory capacity can be reduced owing to vascular, myocardial, extravascular compressive and metabolic factors, all of which may predispose to myocardial ischaemia and consequently ventricular dysfunction. Vascular alterations at the level of the intramural arterioles are characterized by medial hypertrophy and perivascular fibrosis, as well as by an endothelial dysfunction leading to an inappropriate vasodilator function and an increased vasoconstrictor response. Functional and structural alterations of the intramyocardial vasculature may even precede the development of left ventricular hypertrophy, which may further reduce coronary microcirculation by scar formation and increased end-diastolic pressure. In dilated hearts, coronary reserve is further reduced by an increased metabolic demand. Anti-hypertensive therapy in acute hypertensive situations should aim to reduce afterload, lower metabolic demand and increase myocardial coronary blood flow. Long-term anti-hypertensive therapy aims to achieve reparation of the vasculature and regression of myocardial hypertrophy and fibrosis, consequently improving systolic and diastolic function.

This paper reviews technical, methodological and clinical aspects of ambulatory blood pressure (aBP) monitoring. It describes deficits in the evaluation of available aBP devices and in the description and interpretation of slow (e.g. seasonal or circadian) and fast blood pressure variations. The ongoing discussion about the mere existence of circadian blood pressure rhythms is reflected, referring to the most recent data. Further methodological questions considered encompass the problem of centrality (how to describe an aBP profile with one numerical measure) and the question of variability (how to describe variance within an aBP profile). Good reasons for the use of MESOR or RMSSD parameters are given. Finally, the evidence behind a broad clinical application of aBP measurements is critically reviewed; except for ‘white coat’ hypertension, the clinical superiority of aBP values compared with office and home blood pressure readings is not well established on epidemiological grounds.

Hypertension predisposes to a heightened risk of cardiovascular events over years of follow-up of ambulatory adults and especially during the relatively brief peri-and intra-operative periods of heightened stress resulting from surgery and anaesthetic effects. Structural changes in the circulation, including left ventricular and resistance vessel hypertrophy, and systemic and coronary atherosclerosis, play an even more important role in the development of these morbid events than does the actual level of blood pressure elevation. However, chronic anti-hypertensive therapy stabilizes blood pressure and heart rate responses to stress and therapy, thereby decreasing the incidence of ischaemia, congestive heart failure, arrhythmia and cerebrovascular accident. Although optimal evidence is not yet available, it appears that continued anti-hypertensive therapy is as beneficial in the operative setting as it is chronically. Excluding diuretics and angiotensin-converting enzyme inhitors, most other anti-hypertensive medications should be continued during anaesthesia.

For intra-operative hypertension, many drugs are used, but the most evidence of cardioprotective effects has been obtained for the beta-blockers. It is important to mention that calcium-channel blockers may potentiate myocardial depression and bradycardia especially when beta-blockers are already being used.

Arterial hypertension represents the most frequent cardiovascular abnormality encountered by an anaesthetist during the peri-operative period. The diagnosis of arterial hypertension prompts anaesthetists to make far-reaching clinical decisions regarding the pre-operative evaluations of the possible risks for their patients during anaesthesia and surgery, cancellation of surgery in patients with poorly controlled hypertension, adjustment of anti-hypertensive drug therapy, optimal anaesthetic management and safe use of intravenous agents for blood pressure control, to name only a few. Over the past few years, the understanding of the pathophysiology of hypertension has increased considerably, and many new anti-hypertensive drugs have been introduced that may produce significant interactions with anaesthesia. This introductory chapter shows how the new knowledge that is presented in this book may be used for all of the clinical decisions mentioned above, and it attempts to convince the readers that arterial hypertension means much more than just the ‘number of millimetres of mercury’.