Effectiveness and tolerability of low-dose oral oxycodone/naloxone added to anticonvulsant therapy for noncancer neuropathic pain: an observational analysis

BACKGROUND

Opioids may alleviate chronic neuropathic pain (NP), but are considered second/third-line analgesia due to their poor gastrointestinal (GI) tolerability. A fixed combination of prolonged-release oxycodone and naloxone (OXN) has been developed to overcome the GI effects. The aim of this analysis was to evaluate analgesic effectiveness and tolerability of low-dose OXN in patients with moderate-to-severe noncancer NP despite analgesia.

METHODS

This retrospective observation of consecutive adult patients, treated open-label for 8 weeks at a single Italian centre, evaluated effectiveness (pain intensity numerical rating scale [NRS], Patients' Global Impression of Change [PGIC], Douleur Neuropathique 4 inventory [DN4] and Chronic Pain Sleep Inventory [CPSI]), doses of daily OXN and adjuvant medication, rescue paracetamol use, bowel function index (BFI), laxative use, and safety.

RESULTS

Of 200 patients (mean age 65.9 years; 54% female) with NP included in the analysis; 97% completed 8 weeks' treatment. At the observation start, all patients were taking anticonvulsants and complained of constipation, and 60% were receiving opioids. Pain intensity and DN4 score decreased significantly by endpoint (NRS p < 0.0001; DN4 p < 0.0001) and need for rescue analgesics abated. Reduction in pain intensity throughout the observation was similar regardless of NP aetiology. According to PGIC, 87.8% of patients were much/extremely improved, CPSI (p < 0.0001) and BFI were significantly improved (p < 0.0001) and laxative use decreased. No differences were found between patients <65 years vs those ≥65 years. OXN was generally well tolerated.

STUDY LIMITATIONS

Study limitations including the retrospective observational design, the lack of a control group and the single-centre design may limit the generalizability of our findings.

CONCLUSIONS

Low-dose OXN (25.0 ± 12.5 mg/day) added to anticonvulsants was highly effective in controlling noncancer NP of varied aetiology, with reduced need for rescue analgesia and improved quality of sleep, and was well tolerated, with improved bowel function and reduced laxative use. The efficacy and tolerability of OXN demonstrated in this real-world setting suggest its utility in this difficult to manage patient population.

Role of the informed consent, from mesotherapy to opioid therapy

Informed consent is part of a process of communication useful to obtain an agreement (conscious, voluntary and free) between doctors and patients. Mesotherapy is based on the introduction of drugs by intradermal route in order to obtain a dose-sparing effect with respect to deeper administration. Opioids are the most appropriate therapy for patients who do not respond to other therapies. Proper communication between doctor and patient, including an explanation of the potential benefits, limitations and risks (even mild), is recommended both in clinical practice and research. Active participation of the patient has the advantage of better control of adverse events, both of mesotherapy and opioid-based therapy. This information-education process returns to the fundamental concept of "first do no harm" and set a "therapeutic partnership" with patients.

Decompressive craniectomy may cause diagnostic challenges to assess brain death by computed tomography angiography

According to Italian legislation to diagnose brain death (BD) after the initial documentation of the clinical signs, repetition of clinical testing and confirmation of the loss of bioelectrical activity of the brain (EEG) is required. However, when EEG is unreliable it is necessary to demonstrate cerebral circulatory arrest (CCA). Accepted imaging techniques to demonstrate CCA include: cerebral angiography, cerebral scintigraphy, transcranial Doppler (TCD) and computed tomography angiography (CTA). This latter technique, due to its large availability, low invasivity and easy and fast acquisition is widely used over the country. Nevertheless its diagnostic reliability is affected by some limitations in patients with decompressive craniectomy. Here we report two cases of brain injury with clinical signs of BD and at the same time, opacification of intracranial arteries on CTA and a pattern consistent with flow arrest on the corresponding insonable arteries on TCD. The discrepancy between CTA and TCD results points out a methodology limitation that could be overcome by updating Italian legislation according to other European Countries legislation.

The First Point Prevalence Survey of Nosocomial Infections in Albania: Pilot Study

In May 2003, investigators were trained and prevalence pilot study was conducted at the University Hospital of Tirana, Albania. Investigators were trained to assess the organizational problems of the first prevalence survey of nosocomial infections (NIs) in Albania. Twelve investigators were trained in 2 days. After the training, the pilot study was conducted in 3 wards. The investigators collected data using a standard form and the definitions of the Centers for Disease Control, USA. The training improved the investigators' knowledge of NI epidemiology and surveillance. The pilot study underlined the lack of information in the clinical documentation and lack of collaboration between clinicians and the laboratory: microbiological examinations were performed only in 13 (16.5%) patients and none of the 11 NIs reported was confirmed in the laboratory. This led to a review of the survey protocol, above all in order to increase the use of microbiological laboratory.

Mesotherapy, definition, rationale and clinical role: a consensus report from the Italian Society of Mesotherapy

OBJECTIVE

Since its introduction in the 1950s, the use of mesotherapy has generated much interest among clinicians and patients. The Italian Society of Mesotherapy (SIM) brought together a panel of experts to review available evidence and to draw up a series of recommendations on the use of intradermal therapy (LIT) in clinical practice.

CONSENSUS REPORT

There was overwhelming agreement among Consensus Group members that, when used correctly, LIT is a valuable therapeutic option in the treatment of painful, loco-regional conditions. They also emphasised that the clinical efficacy of LIT has been demonstrated in the management of chronic venous lymphatic insufficiency, oedematous fibrosclerotic panniculopathy and facial skin aging. The experts were unanimous on the use of LIT in vaccination. Mesotherapy is not a substitute for other therapeutic options and should only be used when the patient has been fully informed of its advantages and limitations. Likewise the procedure should only be carried out by an experienced qualified physician.

CONCLUSIONS

Although there was widespread agreement among the Consensus Group on the place of LIT in several indications, the Authors reiterated the need for more large-scale clinical trials to determine the specific benefits and limitations in some areas of the application of intradermal therapy.

Long-term controlled-release oxycodone and pregabalin in the treatment of non-cancer pain: an observational study

AIMS

This study evaluates the efficacy and tolerability of long-term controlled-release (CR) oxycodone + pregabalin in patients with non-cancer pain, in a real-life setting.

METHODS

Patients (n = 1,051) with chronic uncontrolled non-cancer pain received CR oxycodone + pregabalin for 1 year. Pain intensity was rated on an 11-point numerical rating scale (NRS) at months 1, 2, 4, 6, 9 and 12.

RESULTS

Throughout the study period, the NRS score decreased significantly (baseline: 7.02 ± 1.26; 12 months: 1.45 ± 0.92; p = 0.00001). Following an initial increase in the mean daily doses of CR oxycodone (starting dose: 12.5 ± 8.4 mg) and pregabalin (starting dose: 121.7 ± 97.2 mg), dose reductions were seen for both drugs with the trend particularly evident for CR oxycodone. 23% of patients withdrew from the study, mainly due to adverse events (67.9% of withdrawn subjects). However, 19.7% of withdrawn patients were removed from the study due to complete relief from chronic pain. The combination was generally well tolerated and there were no reports of addiction.

CONCLUSION

The combination of CR oxycodone + pregabalin could represent a valuable long-term therapeutic addition to existing pharmacological options for the treatment of non-cancer pain.

Opioid-related bowel dysfunction: prevalence and identification of predictive factors in a large sample of Italian patients on chronic treatment

BACKGROUND AND OBJECTIVES

Opioid-bowel dysfunction (OBD) is a broad range of symptoms potentially associated with opioid therapy. This prospective, multicentric study assesses the prevalence of OBD in patients on analgesic therapy for the treatment of pain from any cause and identifies the factors associated with the onset of this side effect.

MATERIALS AND METHODS

Consecutive patients aged > 18 years, on analgesic treatment with opioids, non-steroidal anti-inflammatory drugs (NSAIDs) or other therapies for chronic pain of any aetiology were included in the study. The association of OBD with gender, age, pain aetiology and analgesic treatment was analyzed by multivariate analysis and logistic analysis.

RESULTS

In total, 2324 patients were included in the study. The prevalence of OBD symptoms was 63.5%, despite that the wide majority of patients (89.5%) were receiving laxatives. OBD symptoms were judged as directly correlated with analgesic therapy in 85.1% of cases. The highest prevalence of constipation was reported with morphine, whereas the lowest was observed in patients on oxycodone CR and buprenorphine TTS. Statistical analysis showed that patients on opioids have a higher likelihood of experiencing OBD symptoms than those on NSAIDs or other treatments (66.2% vs 37.0%), and this probability is even higher in those with cancer-related pain (69.3%). Female gender and age > 70 years also appeared as risk factors. The logistic analysis indicated that cancer-related pain, increased age and the use of fentanyl are positive predictors of the presence of OBD, whereas the administration of oxycodone CR was associated with a decreased incidence of these symptoms.

DISCUSSION

Even with the limitation of any observational experience, this study suggests, for the first time, the existence of some factors predictive of the onset of OBD symptoms in patients on analgesic treatment. Moreover, different opioids seem to be associated with a different risk of experiencing these symptoms.

Postoperative pain treatment SIAARTI Recommendations 2010. Short version

The aim of these recommendations is the revision of data published in 2002 in the "SIAARTI Recommendations for acute postoperative pain treatment". In this version, the SIAARTI Study Group for acute and chronic pain decided to grade evidence based on the "modified Delphi" method with 5 levels of recommendation strength. Analgesia is a fundamental right of the patient. The appropriate management of postoperative pain (POP) is known to significantly reduce perioperative morbidity, including the incidence of postoperative complications, hospital stay and costs, especially in high-risk patients (ASA III-V), those undergoing major surgery and those hospitalized in a critical unit (Level A). Therefore, the treatment of POP represents a high-priority institutional objective, as well as an integral part of the treatment plan for "perioperative disease", which includes analgesia, early mobilization, early enteral nutrition and active physiokinesitherapy (Level A). In order to improve an ACUTE PAIN SERVICE organization, we recommend: --a plan for pain management that includes adequate preoperative evaluation, pain measurement, organization of existing resources, identification and training of involved personnel in order to assure multimodal analgesia, early mobilization, early enteral nutrition and active physiokinesitherapy (Level A); --the implementation of an Acute Pain Service, a multidisciplinary structure which includes an anesthetist (team coordinator), surgeons, nurses, physiotherapists and eventually other specialists; --referring to high-quality indicators in establishing an APS and considering the following key points in its organization (Level C): --service adoption; --identifying a referring anesthetist who is on call 24 hours a day; --patient care during the night and weekend; --sharing, drafting and updating written therapeutic protocols; --continuous medical education; --systematic pain assessment; --data collection regarding the efficacy and safety of the implemented protocols; --at least one audit per year. --a preoperative evaluation, including all the necessary information for the management of postoperative analgesia (Level C); --to adequately inform the patient about the risks and benefits of drugs and procedures used to obtain the maximum efficacy from the administered treatments (Level D). We describe pharmacological and loco-regional techniques with special attention to day surgery and difficult populations. Risk management pathways must be the reference for early identification and treatment of adverse events and chronic pain development.

No evidence of family history as a risk factor for herpes zoster in patients with post-herpetic neuralgia

Little is known about reactivation of latent varicella zoster virus as herpes zoster in individuals with no underlying immunosuppression. Risk factors include age, sex, ethnicity, exogenous boosting of immunity from varicella contacts, underlying cell-mediated immune disorders, mechanical trauma, psychological stress, and immunotoxin exposure. An association between herpes zoster and family history of zoster has been proposed. A case-control study involving patients affected by post-herpetic neuralgia, which usually follows more severe acute herpes zoster, was performed. The patients with post-herpetic neuralgia were enrolled at the Pain Clinic of the Policlinico Tor Vergata in Rome, Italy, within 1 year from the onset of acute zoster. The controls matched for sex and age were chosen among healthy subjects without a history of herpes zoster presenting at the Internal Medicine Outpatient Clinic for hypertension in the same time period. All the participants in the study gave informed consent and were interviewed by medically trained and blinded investigators using a questionnaire. Similar proportions of the patients and the controls reported a family history of herpes zoster irrespective of the degree of relationship, i.e., 17.4% and 18.2%, respectively, by analyzing only the first-degree relatives [RR 1.03 (CI 95%: 0.78-1.37)], and 28.4% and 29.6%, respectively, by analyzing the total number of relatives [RR 1.03 (CI 95%: 0.81-1.31)]. Further and larger prospective cohort studies are needed to ascertain whether a family history of herpes zoster is really an independent predictor of zoster in different geographical settings.

Pregabalin in the treatment of chronic pain: an overview

Chronic 'pathological' pain is sustained by mechanisms of peripheral and central sensitization, which are being increasingly investigated at the molecular and cellular levels. The molecular determinants of nociceptive sensitization are natural targets for potential analgesic drugs used in the treatment of different forms of pain. Most of these determinants are common to all forms of chronic pain, and it is therefore not surprising that drugs specifically targeted for the treatment of neuropathic pain are effective in relieving nociceptive inflammatory pain and vice versa. The molecular mechanisms of sensitization that occur in peripheral nociceptors and the dorsal horns of the spinal cord are putative targets for context-dependent drugs, i.e. drugs that are able to discriminate between 'normal' and 'pathological' pain transmission. Among these, pregabalin and gabapentin bind to the alpha(2)delta subunit of voltage-sensitive Ca2+ channels, which sustain the enhanced release of pain transmitters at the synapses between primary afferent fibres and second-order sensory neurons under conditions of chronic pain. Pregabalin in particular represents a remarkable example of a context-dependent analgesic drug that acts at a critical step of nociceptive sensitization. Preclinical and clinical data suggest that pregabalin is more than a structural and functional analogue of gabapentin and may be effective in the treatment of nociceptive inflammatory pain that is resistant to gabapentin.

The first prevalence survey of nosocomial infections in the University Hospital Centre 'Mother Teresa' of Tirana, Albania

A survey was conducted in the largest hospital in Albania to estimate the prevalence and risk factors for nosocomial infections (NIs). A one-day prevalence survey was carried out between October and November 2003 in medical, surgical and intensive care wards. Centers for Disease Control and Prevention definitions were used. Study variables included patient and hospital characteristics, surgical procedures, invasive devices, antibiotic treatment, microbiological and radiological examinations, infection signs and symptoms. Risk factors were determined using logistic regression. In all, 185 NIs were found in 163 of 968 enrolled patients. Urinary tract infections (33.0%), surgical site infections (24.3%), pneumonia (13.0%) and venous infections (9.2%) were the most frequent NIs. The prevalence of NIs was higher in intensive care units (31.6%) than in surgical (22.0%) and medical wards (10.3%). Overall, 132 NIs (71.4%) were confirmed by microbiological examination; the single most frequently isolated micro-organism was Staphylococcus aureus (18.2%). By means of logistic regression, the following independent risk factors were identified: age >40 years, length of hospital stay, 'trauma' diagnosis at admission, and invasive devices. Even though comparisons must be made with great caution, the prevalence of NIs was higher than in western European countries and in some developing countries.

Scrambler therapy

In neuropathies there are complex reactions that modify the homeostatic equilibrium of pain system. In such a context the Scrambler Therapy (ST5) interferes with pain signal transmission, by ''mixing'' a ''non-pain'' information into the nerve fibres. The aim of this study is to evaluate the effectiveness of ST5 in the treatment of neuropathic pain. The ST5 consists of a multiprocessor apparatus able to simulate 5 artificial neurons by the application of surface electrodes on skin pain areas. A total of 226 patients, all suffering from intense drug-resistant neuropathic pain, were recruited for this trial in 2004.

INCLUSION CRITERIA

neuropathic pain, very high baseline visual analogue scale (VAS).

EXCLUSION CRITERIA

pacemaker users, neurolithic blocks or neurolesive pain control treatment. The treated neuropathic pain syndromes were: failed back surgery syndrome (FBSS), sciatic and lumbar painpost-herpetical (PHN), trigeminal neuralgia, post-surgery nerve lesion neuropathy, pudendal neuropathy, brachial plexus neuropathy, low back pain (LBP), others. The trial programme: 1 to 6 therapy sessions of 5 treatments, each one lasting 30 min. Pain intensity was evaluated using VAS before and after each treatment. The statistical significance of VAS was measured using the paired t-test. The total results show 80.09% of responders (pain relief>50%), 10.18% of partially responders (pain relief from 25% to 49%) and 9.73% of no responders (patients with pain relief<24% or VAS>3). The

CONCLUSIONS

is draen that ST5 produced a statistically significant (P<0.0001) pain relief in all treated neuropathies.

Intentional lateral epidural catheter placement for anterior cruciate ligament reconstruction

BACKGROUND

Unilateral epidural block might constitute a clinical option in lower limb orthopedic surgery.

METHODS

Seventy-five patients undergoing anterior cruciate ligament reconstruction (ACLR) were randomized to either a laterally directed epidural catheter (IUEC, n = 40) or a classic midline catheter (CMEC, n = 35). Paresthesia encountered during catheter insertion was registered. The start dose of the anesthetic mixture clonidine 60 microg (0.4 ml), sufentanil 15 microg (0.3 ml) and ropivacaine 10 mg ml(-1)(10.3 ml) in 11 ml of total volume) was set at 5 ml and was increased by 2 ml if anesthesia was inadequate after assessment for sensory blockade to cold and pin-prick. Data were registered intra- and postoperatively regarding pain scores as well as motor block, hemodynamic parameters, adverse effects and need for supplemental analgesia other than a continuous postoperative epidural infusion.

RESULTS

In the IUEC group 80% of patients reported a light paresthesia of the affected side during catheter insertion, whereas 71% of patients in the CMEC group reported no paresthesia at all. The amount of anesthetic used to establish surgical anesthesia was lower in the IUEC group (6.2 +/- 0.8 vs. 8 +/- 1.9 ml, P < 0.001). Motor block (Bromage score) of the unaffected side was significantly lower in the IUEC group (P < 0.001). Pain intensity scores, hemodynamic parameters, and supplemental analgesia given were similar between the two groups except for VAS scores at 12 h postoperatively, which were higher in the CMEC group (P < 0.01). Urinary retention was significantly more frequent in the CMEC group (19/35 vs. 5/40, P < 0.001).

CONCLUSION

These results suggest that the IUEC technique is a feasible and efficient method for providing anesthesia and analgesia for ACLR and is associated with a lower consume of anesthetics, less motor block and a reduced incidence of urinary retention.

Combined general and epidural anesthesia with ropivacaine for renal transplantation

AIM

To evaluate the effectiveness and safety of epidural ropivacaine anesthesia in association with light general anesthesia during renal transplantation and compare epidural and endovenous analgesia techniques for postoperative pain control.

METHODS

EXPERIMENTAL DESIGN

prospective randomized study.

SETTING

Organ Transplantation Center, Department of Surgery, "Tor Vergata" University of Rome, St. Eugenio Hospital, Rome.

PATIENTS

25 patients affected by chronic renal failure were enrolled in this study. Thirteen constituted the combined epidural-general anesthesia group (EPI-GEN), mean age 40.15+/-9.81 years; while the others constituted the general anesthesia group (GEN), mean age 46.75+/-7.45 years. Operation: cadaveric renal transplantation. Group EPI-GEN: epidural anesthesia performed with 12-15 ml of a ropivacaine 0.75% and fentanyl 5 microg/ml solution followed by light intravenous or inhalatory general anesthesia and postoperative epidural analgesia with ropivacaine 0.2% and fentanyl 2 mg/ml. Group GEN: inhalatory or intravenous general anesthesia and intravenous tramadol postoperative analgesia.

MEASUREMENTS

hemo-dynamics, renal function, arterial blood gases analysis, acid-base balance and postoperative pain data was collected and examined.

RESULTS

Postoperative epidural analgesia resulted significantly more effective than intravenous tramadol. PaO(2)/FiO(2) ratio was significantly higher in group EPI-GEN patients both on awakening and throughout postoperative observation. Hemodynamics and renal function did not appear to differ significantly.

CONCLUSION

Combined epidural-general anesthesia is as valid a technique as any for renal transplantation; however postoperative epidural ropivacaine analgesia resulted more effective than intravenous tramadol. Respiratory function appeared less affected, facilitating a fast and uncomplicated postoperative recovery.

Comparison of epidural, continuous femoral block and intraarticular analgesia after anterior cruciate ligament reconstruction

BACKGROUND

The purpose of this study was to compare three locoregional techniques of pain management after arthroscopic anterior cruciate ligament reconstruction (ACLR).

METHODS

Sixty ASA I-II subjects were enrolled after obtaining written informed consent. Patients were randomly allocated to three groups of 20 subjects. The first group (EPI) received epidural ropivacaine 0.2% plus sufentanil 0.2 micro g ml-1, at 5 ml h-1. Patients in the second group (CFB) were given a continuous infusion of the same analgesic mixture through a femoral catheter. The third group (IA) received a continuous intraarticular infusion of ropivacaine 0.2% plus sufentanil 0.2 micro g ml-1, at 5 ml h-1. All subjects were allowed PCA boluses of 5 ml of local anesthetic. Analgesia was assessed for 36 h after the end of surgery by means of a visual analog scale (VAS) and a verbal scale (VS), as well as the number of PCA boluses administered and the amount of supplementary i.v. ketorolac, if given.

RESULTS

The VAS and VS scores were significantly higher in group IA during the 24 h following surgery. Ketorolac requirement was higher in group IA throughout the postoperative observation. Adverse effects were similar in all groups except for urinary retention, which was significantly more frequent in group EPI.

CONCLUSIONS

We conclude that either epidural or continuous femoral nerve block provide adequate pain relief in patients who undergo ACLR, whereas intraarticular analgesia seems unable to cope satisfactorily with the analgesic requirements of this surgical procedure.

Plasma 5alpha-androstane-3alpha,17betadiol, an endogenous steroid that positively modulates GABA(A) receptor function, and anxiety: a study in menopausal women

We tested the hypothesis that changes in endogenous neuroactive steroids acting as positive allosteric modulators of gamma-aminobutyric acid (GABA)(A) receptors may be related to the menopause-associated mood alterations. The study sample consisted of twenty five drug-free menopausal women, 1-3 years since the onset of menopause, homogeneous for age and body mass index (BMI) and without personal history of psychiatric, metabolic or endocrine disorders. Depression and anxiety-related symptoms were assessed with the Zung Self-administered Depression Scale (ZSDS) and the Cornell's Dysthymia Rating Scale (CDRS). The cut-off value predicted by the ZSDS index defined two groups of women (asymptomatic [35.5+/-4.6, n=12] and symptomatic [60.8+/-7.9, n=13]), that were also significantly different according to the CDRS scores (10.6+/-3.4 and 31.5+/-12, respectively, P<0.05). Upon evaluation of the scores relative to the anxiety factor of the CDRS (items 11-15) the symptomatic, but not the asymptomatic, group showed a moderate level of anxiety. The plasma concentrations of several neuroactive steroids were measured, after extraction and HPLC purification, by radioimmunoassay with specific antisera. Only dehydroepiandrosterone and its metabolite 5alpha-androstane-3alpha,17betadiol (3alpha-ADIOL), a positive allosteric modulator of GABA(A) receptors, were significantly (P<0.05 and P<0.005) higher (+110% and +64%, respectively) in the asymptomatic group. A highly significant and negative correlation (r=-0.672, P=0.003) was found between the plasma 3alpha-ADIOL concentrations and the scores of the anxiety factor of the CDRS. These data suggest that endogenous 3alpha-ADIOL modulates the central GABAergic tone and that higher 3alpha-ADIOL concentrations could have a role in preventing the expression of anxiety in the asymptomatic women.

Curariform peripheral block of muscular tone selectively increases precentral N30 somatosensory evoked potentials component. A pharmacological study carried out on healthy subjects and parkinsonian syndromes

In the present study we investigated whether the precentral component (N30) of short somatosensory evoked potentials (SEPs) to median nerve stimulation may be modified by peripheral neuromuscular blocking agent in patients affected by rigidity. We, therefore, recorded SEPs in nine Parkinson's disease (PD) patients and in seven psychotic patients affected by neuroleptic malignant syndrome (NMS), all showing severe rigidity. Each patient group was studied before and after the placebo, and before and after an atracurium besilate bolus of 0.05 mg/kg, in a single recording session. At the time of the test the PD patients had not taken any antiparkinsonian therapy for at least 48 h. The same recordings were also taken on nine neurologically normal subjects undergoing surgical procedures. Atracurium administration produced a remarkable amplitude increase of the major precentral component (N30) of SEPs. An atracurium-induced N30 amplitude increase was observed in both PD patients (from 2.41 to 4.07 microV) and NMS psychotic patients (from 2.03 to 3.97 microV), whereas there was a minor N30 amplitude increase in healthy subjects (from 3.53 to 4. 10 microV). The N30 latency was unaffected. Amplitude and latency of the major parietal SEPs component (N20) was unchanged in the three groups studied. Our results lead to the conclusion that a neuromuscular blocking agent is capable of increasing the N30 amplitude in patients affected by severe rigidity, exclusively reducing their muscular tone without interfering with the central dopaminergic system. Thus, a "peripheral gating" of sensory input to the supplementary motor area due to rigidity may play a relevant role in producing the N30 amplitude decrease described in patients affected by degenerative or pharmacologically induced parkinsonism. The reduction of rigidity could be the mechanism by which dopamine may increase the precentral N30 amplitude in parkinsonian syndromes.

Unilateral thoracoscopic reduction pneumoplasty for asymmetric emphysema

OBJECTIVE

We prospectively analyzed the surgical and functional results of unilateral thoracoscopic reduction pneumoplasty which we performed by choice in patients with asymmetric emphysema.

METHODS

Between October 1995 and June 1997, 119 emphysematous patients were examined and 34 were operated upon. Among these, 14 selected patients with asymmetric distribution of emphysema in the lungs underwent unilateral reduction pneumoplasty (ten right, and four left). There were 13 males and one female, with a mean age of 62 years. Eligibility criteria included bullous and non-bullous end-stage emphysema with severe limitation to daily activity.

RESULTS

No patient required conversion to thoracotomy. Mean operative time ranged between 70 and 240 min with a mean of 103 min. There was no postoperative mortality but five patients developed one or more complications: five prolonged air leaks (>7 days); two pulmonary infections; one empyema. No patient required postoperative mechanical ventilation. Median hospital stay was 8 days. At the 3-month follow-up the mean FEV1 increased from 0.8 l to 1.2 l (P < 0.001). Mean FVC increased from 2.6 l to 2.9 l (P < 0.001). The Medical Research Council dyspnea score decreased from a mean of 3.2 to 1.8 (P < 0.001).

CONCLUSIONS

Asymmetric distribution is a frequent finding in patients with severe emphysema. Unilateral thoracoscopic reduction pneumoplasty may represent an ideal approach in this selected group of patients.

Adjuvant pneumomediastinum in thoracoscopic thymectomy for myasthenia gravis

To facilitate initial visualization and subsequent mobilization of the thymus, adjuvant pneumomediastinum was preoperatively induced in 4 patients who underwent video-assisted thoracoscopic thymectomy. Neither mortality nor technique-related morbidity was observed. This experience shows video-assisted thoracoscopic thymectomy to be a safe and reliable procedure. In addition, we believe that adjuvant pneumomediastinum seems to facilitate the dissection maneuvers and could shorten operative time.

The amino acid cerebral pool after toxic doses of lidocaine and mexiletine. An experimental study on guinea pigs

Lidocaine and Mexiletine are two anti-arrhythmic drugs which when administered in toxic doses cause alterations in the central nervous system (convulsions, tremors, coma). An experimental study was carried out to clarify some neurological side-effects caused by these two drugs, by studying the variations of the brain amino acid pool. With Lidocaine one can observe an increase of phenyl-alanine and tyrosine, a decrease of glycine, GABA, alanine, aspartate and glutamate, while taurine and ammonia showed no significant changes. After Mexiletine one can observe an increase of ammonia, a decrease of GABA, glutamine, glycine and alanine, while glutamate, taurine, phenyl-alanine and tyrosine remain within normal values. In conclusion, on the basis of the data obtained by comparing the two drugs, one could say that Lidocaine has a greater interference on the catecholaminic precursors which are little influenced by Mexiletine. For the rest, the data obtained are practically super- imposable .

The brain amino acid pattern in experimental coma due to phenytoin in guinea pigs

An experimental study was carried out on 50 guinea pigs to evaluate the amino acid pattern in the whole brain after a toxic dose of phenytoin (1 g . kg-1 body wt). One group of 25 guinea pigs was treated with the drug which made them comatose, and their brains removed by craniotomy and frozen in liquid nitrogen; 25 guinea pigs were used as a control group. The brain amino acid pattern was determined by ion-exchange chromatography. All the amino acids, except threonine and methionine, decreased. Hypotheses about the particular cerebral metabolic pathways involved are discussed.

Experimental acute hypoxia. Brain preservation by phenobarbital pretreatment. Histological study in guinea pigs

Acute hypoxia was induced by keeping guinea pigs in an atmosphere of 5% O2/95% N2 for 20 min. Four groups of 10 guinea pigs each were used: (A) control; (B) after 20 min of hypoxia; (C) after 20 min of hypoxia and 20 min of oxygen therapy (100%); (D) pretreatment with phenobarbital (100 mg/kg body wt) and 20 min of hypoxia, followed by 20 min of oxygen therapy. The histological study did not show significant differences between barbiturate-treated and untreated hypoxic brains. In fact, the severity of ischemic-hypoxic damage as well as its distribution were similar in all the experimental groups of animals. Lesions predominated in the regions which are known to be more sensitive to hypoxia (3rd and 4th layers of parieto-occipital cortex, Sommer's fields, cerebellum). It is considered that in the experimental conditions barbiturates did not act as a protective agent--at least as assessed morphologically.