Neurological complications following central neuraxial blocks: are there predictive factors?

Severe complications such as spinal epidural haematoma and an array of adverse neurological events leading to temporary or permanent disability have been ascribed to central neuraxial blocks. Infections (meningitis, abscesses), chemical injuries and very rarely cerebral ischaemia or haemorrhage, or both, have also been ascribed directly or indirectly to spinal and/or epidural anaesthesia. Some case reports, and very few retrospective studies, have focused their attention on the fact that central nerve blocks can cause, albeit rarely, permanent damage to the spinal cord or nerve roots, or both. The cause of this damage in many cases remains unclear. The attention of investigators and practitioners is focused both on understanding the causative mechanisms of such accidents and in identifying 'alarm events' that can arise during the administration of a central block, if any. We reviewed the international literature for the neurological complications of central neuraxial blocks to identify some events that, if they occurred during the block procedure, could be perceived as dangerous.

Postoperative analgesia by combined continuous infusion and patient-controlled epidural analgesia (PCEA) following hip replacement: ropivacaine versus bupivacaine.

BACKGROUND: Ropivacaine is a new local anaesthetic, which compared to bupivacaine is less toxic and shows greater sensory and motor block dissociation. We hypothesised that treatment of postoperative pain with a combined regimen of continuous epidural infusion and Patient-Controlled Epidural Analgesia (PCEA) using ropivacaine could have given better results compared with those we had obtained using bupivacaine. METHODS: Patients undergoing total hip replacement were randomly assigned to two groups. They received epidural analgesia for postoperative pain treatment using ropivacaine, 2 mg x ml(-1) or bupivacaine 2 mg x ml(-1). Both drugs were administered as a constant infusion of 6 ml x h(-1) supplemented by PCEA bolus doses of 2 ml. Patients in both groups received morphine intravenously on demand from a patient-controlled analgesia (PCA) device. An independent observer recorded pain scores, intensity of motor block and morphine consumption at regular intervals during the first 24 h after surgery. RESULTS: Fifty-one patients were evaluated. Ropivacaine and bupivacaine, in similar amounts, provided similar results assessed as adequate to very good postoperative analgesia, whereas motor block was significantly more intense in patients treated with bupivacaine. CONCLUSIONS: Despite similar analgesic effects, epidural infusion of ropivacaine combined with PCEA provides higher patient satisfaction than equal doses of bupivacaine due to lack of motor block.

[Epidemiologic analysis of patients afferent to the ICU]. / Studio epidemiologica sull'attività del centro di rianimazione.

BACKGROUND: To understand in- and out-patients flow to and from an ICU during a year (1998). The setting of the study was an 8-beds Intensive Care Unit of a 480-beds General Hospital with an Emergency Department. METHODS: Retrospective analysis by a specific designed software of all patient data extrapolated from the hospital database, in order to: 1) Divide all ICU patients in four groups, according to the first admission Department; 2) Classify all ICU patients into 3 subgroups: a) medical; b) surgical; c) trauma; 3) Evaluate the different needs of ICU resources in these different patient populations. RESULTS: Two hundred and fifty-four patients were admitted to our ICU during the study period (1.2% of all admissions). The mean duration of ICU stay was 10.4 days. Thirty-five per cent of ICU admissions came from the Emergency Department, 61% of ICU patients were discharged to another hospital ward, while the remaining 7% had to be transferred to a different hospital; 2.8% of our patients had ICU re-admissions. The overall mortality rate was 32%. CONCLUSIONS: Compared with previously reported data, a lower re-admission rate (3%), a longer mean stay in the ICU (>10 days) and a higher occupancy rate (91.4%) were observed. These data suggest that a large part of the available resources for the intensive care in our hospital are devoted to the in-hospital patient care. The hypothesis is suggested that this could be mainly due to the lack of sub-critical care areas.

[Technical difficulties in epidural blocks and spinal bleeding complications]. / Difficoltá techniche nell'esecuzione dei blocchi centrali e complicanze emorragiche spinali.

The clinical cases of two patients with neurological complications following neuroaxial blocks are reported. The events took place in different institutions where thousands of central blocks were yearly performed. In both instances the blocking procedures presented technical difficulties needing repeated lumbar punctures. The first case concerns a patient receiving anticoagulant and fibrinolytic therapy for vascular pathology. This 89 year-old female experienced severe cord compression requiring surgical decompression and laminectomy. The second case regards a patient with previous minor surgical procedure requiring postoperative antiinflammatory treatment. This 74 year-old male experienced subarachnoid hemorrhage and spinal/epidural hematoma as shown by NMR. The symptoms regressed with steroid therapy. The authors emphasise the risks of mechanical trauma of epidural or spinal anesthesia both during positioning or removal of an epidural catheter. The problem related to the compatibility between central blocks and antithrombotic/anticoagulant prophylaxis/therapy is now of primary concern and has led to publications about guide lines on this topic. If central block is carried out in patients with bleeding diathesis it is mandatory to co-ordinate multidisciplinary assistance for early detection of significant symptoms of the above described complications and subsequent treatment.

Mepivacaine: update on an evergreen local anaesthetic.

Many local anaesthetics are presently available for clinical use. The choice of a particular agent for a particular regional anaesthetic is based mainly on its clinical and pharmacological features. Besides these, safety of drugs and the knowledge of side effects associated with their use can play a major role, since serious complications can be related to local anaesthetics administration. Pharmacologic features of mepivacaine are: its amide structure (therefore it is not detoxified by circulating plasma esterases), its rapid metabolism, which take place into the liver, and its rapid excretion via the kidneys. Clinically, mepivacaine shows: short onset time, very close to lidocaine, intermediate duration and low toxicity. Mepivacaine can be therefore considered as a first choice agent for peripheral nerve blocks, particularly in high cardiac risk patients.

0.75% and 0.5% ropivacaine for axillary brachial plexus block: a clinical comparison with 0.5% bupivacaine.

BACKGROUND AND OBJECTIVES: Although ropivacaine has been extensively studied for epidural anesthesia, very few reports exist on brachial plexus block. We therefore decided to investigate the clinical features of axillary brachial plexus anesthesia with two different concentrations of ropivacaine (0.5% and 0.75%) and to compare the results with those obtained with 0.5% bupivacaine. METHODS: Three groups of patients were randomized and prospectively studied. They received, in a double-blind fashion, 32 mL of the local anesthetic solution into the midaxilla, by a nerve-stimulator technique. Onset time in each of the stimulated nerves was recorded both for the sensory and motor block. Peak time (ready to surgery), rate of supplemental blocks, need for intraoperative opioids, duration of sensory and motor block, postoperative analgesic requirements, and patient satisfaction were also recorded. RESULTS: The rate of complete sensory and motor block observed with both ropivacaine groups was higher at 10, 15, and 20 minutes postinjection (P < .001). The mean peak time was shorter with ropivacaine than with bupivacaine (R50 = 16.37 minutes, R75 = 14.7 minutes, B = 22.3 minutes, P < .05). The quality of the anesthesia was higher with ropivacaine, as measured by the intraoperative needs for opioids and the overall patient's satisfaction (P < .05). No significant differences were noted with all the other studied parameters. CONCLUSION: Ropivacaine showed advantages over bupivacaine for axillary brachial plexus block. Because no statistical differences were found between the two ropivacaine groups, we therefore conclude that 0.75% does not add benefit and that 0.5% ropivacaine should be used to perform axillary brachial plexus blocks.

A clinical comparison between needle-through-needle and double-segment techniques for combined spinal and epidural anesthesia.

BACKGROUND AND OBJECTIVES: The goal of the present investigation was to compare the double-segment and the needle-through-needle techniques for combined spinal and epidural anesthesia (CSE) in a prospective, randomized, blinded study. METHODS: With Ethical Committee approval and patient's consent, 120 patients were randomized to receive CSE by the needle-through-needle (SST; n=60) or the double-segment technique (DST; n=60). A blind observer measured the time required from skin disinfection to readiness for surgery (loss of pinprick sensation up to T10), failure of dural puncture, need for epidural top-up before surgery, patient acceptance, and occurrence of complications. RESULTS: No neurologic complications were observed in either group. Time to readiness for surgery was 22.7+/-8.2 minutes in the SST group and 29.8+/-8.31 minutes in the DST one (P < .001). Dural puncture was unsuccessful in three patients in the SST group (5%) and in one patient in the DST group (1.6%) (ns); inadequate spread of spinal anesthesia was observed in five patients in the SST group (8.3%) and in eight patients in the DST group (13.3%) (ns). No difference in the incidence of hypotension, postdural puncture headache, and back pain was observed between the two groups. Acceptance of anesthetic procedure was better in the SST (85%) than in the DST group (66.6%) (P < .05). CONCLUSIONS: The needle-through-needle technique for CSE requires less time, has no greater failure rate, and results in greater patient satisfaction than the double-segment technique. The use of a spinal needle with an adjustable locking mechanism and protruding up to 15 mm beyond the Tuohy needle improved successful spinal block in the needle-through-needle technique compared with previous reports.

Unusually prolonged duration of spinal anesthesia following 2% mepivacaine.

BACKGROUND AND OBJECTIVES: Spinal mepivacaine has been reported as a reliable anesthetic for ambulatory anesthesia. Its pharmacologic properties are midway between those of bupivacaine and lidocaine, and it can be used in intermediate duration ambulatory surgical procedures. METHODS: A patient taking clonidine transdermal patches (TTS) to control high blood pressure received spinal mepivacaine for surgical repair of a ruptured meniscus with arthroscopy. RESULTS: The resulting duration of sensory and motor block were 12 and 8.5 hours, respectively. These are more than four times as long as the reported mean durations with this spinal local anesthetic. We hypothesized that the use of clonidine via TTS for the previous 16 months contributed to this unusual delay of recovery from spinal anesthesia. CONCLUSIONS: Clonidine can increase the duration of spinal anesthetics. Even though this well-known effect has been considered mostly beneficial, it can be an adverse effect when spinal ambulatory anesthesia is given to patients receiving clonidine TTS or clonidine in other forms for long-term treatment of hypertension or other diseases.

[Patient-controlled postoperative analgesia in orthopedic surgery: epidural PCA versus intravenous PCA]. / Analgesia postoperatoria controllata dal paziente in chirurgia ortopedica: PCA epidurale versus PCA endovenosa.

OBJECTIVE: To evaluate both effectiveness and incidence of side effects of two techniques of postoperative pain treatment: intravenous and epidural PCA. DESIGN: Prospective analysis of data from two groups of randomized patients. SETTINGS: Orthopedic and trauma center. PATIENTS: Figty ASA class II-III patients undergoing total hip replacement under combined Spinal-Epidural Anesthesia. METHODS: Patients were divided into 2 groups who received different postoperative pain treatment. One group (group PCA) received a patient-controlled intravenous analgesia with morphine 30 mg and ketorolac 90 mg in 100 ml of saline (back-ground infusion 2-4 ml, according to body weith, bolus 1 ml, lockout 5 min, 4 h dose limit 40 ml). PCEA group received a patient-controlled epidural analgesia with morphine 4 mg and bupivacaine 0.125% 100 ml, (background infusion 3-4 ml, according to patient' height, bolus 1 ml, lockout 10 min, 4 h dose limit 25 ml). Postoperative pain intensity was evaluated, through 24 postoperative hours, by a verbal analogue scale (VPS = 0 to 3) and a total pain score (TOTPAR) was calculated for each patient at 6 and 24 postoperative hours. Side effects were recorded and their incidence was obtained for each group. Statistical data analysis was performed by one-way ANOVA and non-parametric tests for ordinal data. Nominal data were analyzed by chi 2 test. p < 0.05 was considered significant. RESULTS: Patient receiving PCEA showed a significant (p < 0.005) decrease of incident pain, while VPS at rest was similar in the two groups. TOTPAR VPS was lower (p < 0.05) in PCEA group both at 6 and 24 postoperative hours. Somnolence was observed more often in PCA patients (8% vs 2%; p 0.05), while no significant differences were noted among other side effects incidence. CONCLUSIONS: Our data show a better control of postoperative pain arising from total hip replacement during PCEA when compared to PCA. It should be emphasized that incident pain is far more decreased by PCEA, so that this technique is particularly indicated when an early postoperative mobilization is required.

The effect of pH adjustment of 2% mepivacaine on epidural anesthesia.

Two-hundred men, scheduled for elective meniscectomy under epidural anesthesia, were randomly assigned to receive either a standard 2% mepivacaine solution (n = 100) or a pH adjusted 2% mepivacaine solution (pHAS, n = 100). The pHAS was freshly prepared before the block by adding 0.1 mEq of NaHCO3 per ml of mepivacaine solution. After a test-dose, the anesthetic solution was injected to produce a level of sensory anesthesia to T10. The mean duration of anesthesia and the mean dose of mepivacaine used were comparable between the groups. Patients in the pHAS group showed a significant shortening of onset time in T10 and in S2 segment (p less than .001). Grade 3 motor blockade was achieved in the same number of patients, but a faster motor block was observed in the pHAS group (p less than .05). Regression of both sensory and motor blockade in the two groups was not significantly different.

Intrathecal buprenorphine for postoperative analgesia in the elderly patient.

Ninety patients aged 56-85 years scheduled for suprapubic prostatectomy, randomly received intrathecally either bupivacaine 30 mg (group A, n = 30), bupivacaine 30 mg plus buprenorphine 0.03 mg (group B, n = 30) or bupivacaine 30 mg plus buprenorphine 0.045 mg (group C, n = 30). Prolonged postoperative analgesia, minimal disturbance of consciousness and comfortable breathing were common to the groups that received buprenorphine. The higher concentration of buprenorphine improved the quality and duration of analgesia. The only side effects found in the buprenorphine groups were nausea and vomiting in 11 and 14 patients, respectively, in groups B and C. Our study shows that buprenorphine is an effective analgesic, suitable for the management of postoperative pain in elderly patients.