The PINE study: rationale and design of a randomised comparison of epidural injection of local anaesthetics and steroids versus care-as-usual to prevent postherpetic neuralgia in the elderly [ISRCTN32866390].

BACKGROUND: Postherpetic neuralgia (PHN) is by far the most common complication of herpes zoster (HZ) and one of the most intractable pain disorders. Since PHN is seen most often in the elderly, the number of patients with this disorder is expected to increase in our ageing society. PHN may last for months to years and has a high impact on the quality of life.

Quality of perioperative AEP--variability of expert ratings.

Background: Previous studies suggest that auditory evoked potentials (AEP) may be used to monitor anaesthetic depth. However, during surgery and anaesthesia, the quality of AEP recordings may be reduced by artefacts. This can affect the interpretation of the data and complicate the use of the method.

Role of history and physical examination in preoperative evaluation.

Background And Objective: Since reports have shown that outpatient preoperative evaluation increases the quality of care and cost-effectiveness, an increasing number of patients are being evaluated purely on an outpatient basis. To improve cost-effectiveness, it would be appealing if those patients who are healthy and ready for surgery without additional testing could be easily distinguished from those who require more extensive evaluation. This paper examines whether published studies provide sufficient data to determine how detailed preoperative history taking and physical examination need to be in order to assess the health of surgical patients and to meet the objective of easy and early distinction.

Interaction between the spinal melanocortin and opioid systems in a rat model of neuropathic pain.

Background: The authors recently demonstrated that administration of the melanocortin-4 receptor antagonist SHU9119 decreased neuropathic pain symptoms in rats with a sciatic chronic constriction injury. The authors hypothesised that there is a balance between tonic pronociceptive effects of the spinal melanocortin system and tonic antinociceptive effects of the spinal opioid system. Therefore, they investigated a possible interaction between these two systems and tested whether opioid effectiveness could be increased through modulation of the spinal melanocortin system activity.

The effect of zero-balanced ultrafiltration during cardiopulmonary bypass on S100b release and cognitive function.

Zero-balanced ultrafiltration (ZBUF) might reduce the systemic inflammatory response (SIRS) during cardiopulmonary bypass (CPB) by removing inflammatory mediators. The objective of this study was to determine the effect of ZBUF on postoperative serum S100b levels, a marker of neuronal injury. In addition, the possible effects of ZBUF on postoperative neurocognitive function were assessed.

Cognitive self-assessment one year after on-pump and off-pump coronary artery bypass grafting.

Background: Coronary artery bypass grafting (CABG) is associated with significant cerebral morbidity. This is usually manifested as cognitive decline and may be caused by cardiopulmonary bypass. The primary objective of this study was to explore whether patients report more cognitive failures 1 year after CABG than preoperatively.

A comparison of on-pump and off-pump coronary bypass surgery in low-risk patients.

Background: The performance of coronary bypass surgery without cardiopulmonary bypass ("off pump") may reduce perioperative morbidity and costs, but it is uncertain whether the outcome is similar to that involving the use of cardiopulmonary bypass ("on pump").

Methods: In a multicenter, randomized trial, we randomly assigned 139 patients with predominantly single- or double-vessel coronary disease to on-pump surgery and 142 to off-pump surgery. Cardiac outcome and cost effectiveness were determined one year after surgery.

Haemodynamic changes during low-pressure carbon dioxide pneumoperitoneum in young children.

Background: Both mechanical and pharmacological effects may contribute to the haemodynamic consequences of carbon dioxide (CO2) pneumoperitoneum. The aim of the present study was to evaluate the haemodynamic effects of low-pressure pneumoperitoneum [intra-abdominal pressure (IAP) 5 mmHg] in young children (< 3 years).

Methods: Thirteen children, aged 6-36 months, ASA physical status I-III, who were scheduled for laparoscopic fundoplication for gastro-oesophageal reflux were investigated in the head-up position (10 degrees ).

Validation of a clinical prediction rule to reduce preoperative type and screen procedures.

Background: We have developed a prediction rule for the occurrence of perioperative red blood cell transfusion to help to reduce the number of unnecessary preoperative type and screen procedures. We evaluated the robustness of this prediction rule in patients from another hospital.

Methods: The rule was retrospectively applied to 1282 consecutive patients ('validation set') who underwent similar surgical procedures to the patients in the derivation study.

The role of transcranial motor evoked potentials in predicting neurologic and histopathologic outcome after experimental spinal cord ischemia.

Background: Monitoring of myogenic motor evoked potentials to transcranial stimulation (tcMEPs) is clinically used to assess motor pathway function during aortic and spinal procedures that carry a risk of spinal cord ischemia (SCI). Although tcMEPs presumably detect SCI before irreversible neuronal deficit occurs, and prolonged reduction of tcMEP signals is thought to be associated with impending spinal cord damage, experimental evidence to support this concept has not been provided. In this study, histopathologic and neurologic outcome was examined in a porcine model of SCI after different durations of intraoperative loss of tcMEP signals.

Cognitive outcome after off-pump and on-pump coronary artery bypass graft surgery: a randomized trial.

Context: Coronary artery bypass graft (CABG) surgery is associated with a decline in cognitive function, which has largely been attributed to the use of cardiopulmonary bypass (on-pump procedures). Cardiac stabilizers facilitate CABG surgery without use of cardiopulmonary bypass (off-pump procedures) and should reduce the cognitive decline associated with on-pump procedures.

Objective: To compare the effect of CABG surgery with (on-pump) and without (off-pump) cardiopulmonary bypass on cognitive outcome.

Predictive performance of a physiological model for enflurane closed-circuit anaesthesia: effects of continuous cardiac output measurements and age-related solubility data.

Background: The disposition of inhalation anaesthetics is governed by the factors described in the Fick principle.

Methods: We have recalibrated a previously validated physiological model for enflurane closed-circuit inhalation anaesthesia, using individual continuous cardiac output measurements as well as age-related enflurane solubility coefficients as inputs to the model. Two model versions using 'calculated' (Brody's formula) or 'measured' (thoracic electrical bioimpedance) cardiac output values, and two versions with 'standard' (fixed) or 'age-related' solubility coefficients were formulated.

Delayed detection of motor pathway dysfunction after selective reduction of thoracic spinal cord blood flow in pigs.

Objective: Clinical monitoring of myogenic motor evoked potentials to transcranial stimulation provides rapid evaluation of motor-pathway function during surgical procedures in which spinal cord ischemia can occur. However, a severe reduction of spinal cord blood flow that remains confined to the thoracic spinal cord might render ischemic only the descending axons of the corticospinal pathway. In this situation lower-limb motor evoked potentials could respond relatively late compared with a similar spinal cord blood flow reduction of the lumbar spinal cord that renders predominantly motoneurons ischemic.

The effect of outpatient preoperative evaluation of hospital inpatients on cancellation of surgery and length of hospital stay.

Unlabelled: To evaluate the possible effects of outpatient preoperative evaluation (OPE) for new surgical patients who will be inpatients, we conducted an observational study at a university hospital in The Netherlands. Various outcomes before and after the introduction of an OPE clinic were compared. The study population comprised all 21,553 elective adult inpatients operated on between January 1, 1997 and December 31, 1999.

The effects of low-pressure carbon dioxide pneumoperitoneum on cerebral oxygenation and cerebral blood volume in children.

Unlabelled: We examined the effects of low-pressure carbon dioxide pneumoperitoneum on regional cerebral oxygen saturation (ScO(2)) and cerebral blood volume (CBV) in children. Fifteen children, ASA I--III, scheduled for laparoscopic fundoplication, were investigated in the head-up position (10) and ventilated to a baseline end-tidal CO(2) (PETCO(2)) between 25 and 33 mm Hg. Ventilatory settings remained unchanged during the operation.

Spinal cord blood supply in patients with thoracoabdominal aortic aneurysms.

Objective: In patients with thoracoabdominal aortic aneurysms (TAAAs), the blood supply to the spinal cord is highly variable and unpredictable because of obstructed intercostal and lumbar arteries. This study was performed for the prospective documentation of patent segmental arteries during TAAA repair and the assessment of their functional contribution to the spinal cord blood supply.

Methods: TAAA repair was performed in 184 consecutive patients (68 with type I aneurysm, 91 with type II, and 25 with type III) according to a protocol that included left heart bypass grafting, cerebrospinal fluid drainage, and the monitoring of motor-evoked potentials (MEPs).

Spinal cord monitoring: somatosensory- and motor-evoked potentials.

Monitoring myogenic motor EPs after transcranial electrical stimulation is effective in detecting spinal cord ischemia. During thoracoabdominal aortic aneurysm surgery, this technique is sufficiently rapid to allow timely interventions aimed at correcting ischemic conditions and preserving spinal cord blood flow. If strategies are applied to protect the spinal cord during thoracoabdominal aortic aneurysm repair (e.

Peri-ischemic aminoguanidine fails to ameliorate neurologic and histopathologic outcome after transient spinal cord ischemia.

Inhibition of neurotoxic events that lead to delayed cellular damage may prevent motor function loss after transient spinal cord ischemia. An important effect of the neuroprotective substance aminoguanidine (AG) is the inhibition of inducible nitric oxide synthase (iNOS), a perpetrator of focal ischemic damage. The authors studied the protective effects of AG on hind limb motor function and histopathologic outcome in an experimental model for spinal cord ischemia, and related these findings to the protein content of iNOS in the spinal cord.

Neuropathic pain: a possible role for the melanocortin system?

In humans, damage to the nervous system can lead to a pain state referred to as neuropathic pain. Here, we give a short overview of the clinical picture and classification of neuropathic pain and highlight some of the currently known pathophysiological mechanisms involved, with special emphasis on neuropeptide plasticity. In this context, we discuss a specific group of neuropeptides, the melanocortins.

Wavelet analysis of middle latency auditory evoked responses: calculation of an index for detection of awareness during propofol administration.

Background: Middle latency auditory evoked responses (MLAER) as a measure of depth of sedation are critically dependent on data quality and the analysis technique used. Manual peak labeling is subject to observer bias. This study investigated whether a user-independent index based on wavelet transform can be derived to discriminate between awake and unresponsive states during propofol sedation.

Randomized controlled trial of total intravenous anesthesia with propofol versus inhalation anesthesia with isoflurane-nitrous oxide: postoperative nausea with vomiting and economic analysis.

Background: To assess the incidence of postoperative nausea and vomiting after total intravenous anesthesia (TIVA) with propofol versus inhalational anesthesia with isoflurane-nitrous oxide, the authors performed a randomized trial in 2,010 unselected surgical patients in a Dutch academic institution. An economic evaluation was also performed.

Methods: Elective inpatients (1,447) and outpatients (563) were randomly assigned to inhalational anesthesia with isoflurane-nitrous oxide or TIVA with propofol-air.

Predictability of processed electroencephalography effects on the basis of pharmacokinetic-pharmacodynamic modeling during repeated propofol infusions in patients with extradural analgesia.

Background: Pharmacokinetic-pharmacodynamic (PKPD) modeling can be used to characterize the concentration-effect relation of drugs. If the concentration-effect relation of a hypnotic drug is stable over time, an effect parameter derived from the processed electroencephalographic signal may be used to control the infusion for hypnosis. Therefore, the stability of the propofol concentration-electroencephalographic effect relation over time was investigated under non-steady state conditions.