Anesthesia and analgesia
-
Anesthesia and analgesia · Mar 2003
Comparative StudyOrganizational factors affect comparisons of the clinical productivity of academic anesthesiology departments.
Productivity measurements based on "per operating room (OR) site" and "per case" are not influenced by staffing ratios and have permitted meaningful comparisons among small samples of both academic and private-practice anesthesiology groups. These comparisons have suggested that a larger sample would allow for clinical groups to be compared using a number of different variables (including type of hospital, number of OR sites, type of surgical staff, or other organizational characteristics), which may permit more focused benchmarking. In this study, we used such grouping variables to compare clinical productivity in a broad survey of academic anesthesiology programs. Descriptive, billing, and staffing data were collected for 1 fiscal or calendar year from 37 academic anesthesiology departments representing 58 hospitals. Descriptive data included types of surgical staff (e.g., academic versus private practice) and hospital centers (e.g., academic medical centers and ambulatory surgical centers [ASCs]). Billing and staffing data included total number of cases performed, total American Society of Anesthesiologists units (tASA) billed, total time units billed (15-min units), and daily number of anesthetizing sites staffed (OR sites). Measurements of total productivity (tASA/OR site), billed hours per OR site per day (h/OR/d), surgical duration (h/case), hourly billing productivity (tASA/h), and base units/case were compared. These comparisons were made according to type of hospital, number of OR sites, and type of surgical staff. The ASCs had significantly less tASA/OR site, fewer h/OR/d, and less h/case than non-ASC hospitals. Community hospitals had significantly less h/OR/d and h/case than academic medical centers and indigent hospitals and a larger percentage of private-practice or mixed surgical staff. Academic staffs had significantly less tASA/h and significantly more h/case. tASA/h correlated highly with h/case (r = -0.68). This study showed that the hospitals at which academic anesthesiology groups provide care are not all the same from a clinical productivity perspective. By grouping based on type of hospital, number of OR sites, and type of surgical staff, academic anesthesiology departments (and hospitals) can be better compared by using clinical productivity measurements based on "per OR site" and "per case" measurements (tASA/OR, billed h/OR/d, h/case, tASA/h, and base/case). ⋯ Organizational factors, including type of hospital, number of operating rooms, and type of surgical staff, influence the clinical productivity of academic anesthesiology departments. Reporting quartile data by focused grouping variables allows anesthesiology groups to compare their clinical productivity with groups practicing in similar clinical settings.
-
Anesthesia and analgesia · Mar 2003
Clinical TrialChanges in consciousness, conceptual memory, and quantitative electroencephalographical measures during recovery from sevoflurane- and remifentanil-based anesthesia.
It is unclear whether opioid-induced changes in electroencephalogram (EEG) or auditory evoked potentials (AEPs) reliably correspond with consciousness. We examined the correlation between 1) the clinically assessed state of consciousness, 2) implicit and explicit memory (by use of word pairs), and 3) various measures of EEG and AEP-bispectral index (BIS), A-Line ARX AEP index, spectral entropy, and entropy of the singular value decomposition (SVDEN; a measure of the complexity of the EEG). We studied 21 women during a two-stage awakening (sevoflurane washout followed by remifentanil washout) after anesthesia for gynecological surgery. All were amnesic, and 19 were unresponsive to verbal command with remifentanil alone. In six patients, BIS decreased paradoxically as the remifentanil concentration decreased; this was caused by a low-amplitude EEG, which was misinterpreted by the Aspect algorithm as burst suppression. Most of the EEG/AEP variables were sensitive to the decrease in sevoflurane and the recovery of consciousness, but not to the effects of decreasing remifentanil concentrations. SVDEN was the only variable that demonstrated significant increases for both the sevoflurane and remifentanil washout phases. With the prediction probability statistic during remifentanil washout, SVDEN = 0.79, spectral entropy = 0.81, A-Line ARX AEP index = 0.63, and BIS = 0.58. Entropy measures appear to be worthy of further clinical evaluation in a larger series of patients. SVDEN may be a useful variable for assessing anesthetic and analgesic effects on the central nervous system. ⋯ During the recovery phase from a remifentanil-based anesthetic, the bispectral index is not reliably predictive of the depth of consciousness, because of suppression ratio artifacts. Entropy measures of the electroencephalogram show promise, but there is still no gold standard to estimate anesthetic depth.
-
Anesthesia and analgesia · Mar 2003
Clinical TrialInfragluteal-parabiceps sciatic nerve block: an evaluation of a novel approach using a single-injection technique.
Clinical use of the sciatic nerve block (SNB) has been limited by technical difficulties in performing the block using standard approaches, substantial patient discomfort during the procedure, or the need for two injections to block the tibial and peroneal nerves. In this report, we describe a single-injection method for SNB using an infragluteal-parabiceps approach, where the nerve is located along the lateral border of the biceps femoris muscle. SNB was performed in the prone or lateral decubitus position. The needle was positioned (average depth, 56 +/- 15 mm) to the point where plantar flexion (53%) or inversion (45%) of the ipsilateral foot was obtained at < or =0.4 mA. Levobupivacaine 0.625% with epinephrine (1:200:000) was administered at a dose of 0.4 mL/kg. The procedure was completed in 6 +/- 3 min. Discomfort during block placement was treated with fentanyl 50-100 microg in 24% of patients. Complete sensory loss and motor paralysis occurred in 92% of subjects at a median time of 10 (range, 5-25) min after injection. Compared with plantar flexion, foot inversion was associated with a more frequent incidence (86% versus 100%), and shorter latency for both sensory loss and motor paralysis of the peroneal, tibial, and sural nerves. There were no immediate or delayed complications. We conclude that the infragluteal-parabiceps approach to SNB is reliable, efficient, safe, and well tolerated by patients. ⋯ Sciatic nerve block using the infragluteal-parabiceps approach produces sensory loss and motor paralysis after a single 0.4 mL/kg injection of levobupivacaine 0.625% with epinephrine (1:200,000) in >90% of patients. The approach is reliable, uses consistent soft-tissue landmarks, is not typically painful, and does not produce significant complications.
-
Anesthesia and analgesia · Mar 2003
Continuous intrathecal clonidine and tizanidine in conscious dogs: analgesic and hemodynamic effects.
Alpha-2-adrenergic agonists, such as clonidine, produce antinociception in animal pain models after intrathecal administration. However, clinical usage is limited by cardiovascular side effects. To investigate alternative alpha(2)-adrenergic agonists as analgesics, we implanted six dogs with an intrathecal catheter and infusion pump. After baseline saline infusion, animals received clonidine or tizanidine (crossover study) each week at escalating doses of 125-750 microg/h. Analgesia, blood pressure, heart rate, respiratory rate, sedation, and coordination were evaluated. A 28-day safety study was performed with another nine dogs receiving intrathecal tizanidine (3 or 6 mg/d) or saline. Equal doses of clonidine and tizanidine produce the same antinociception in thermal withdrawal tests. Blood pressure was reduced with 125-500 microg/h of clonidine, but not with tizanidine at any dose. Clonidine 250 microg/h reduced heart rate by 45.8%, and five of six animals had bradyarrhythmias (marked bradycardia), whereas tizanidine decreased heart rate by 15.1% without arrhythmias, even at the largest dose. Respiratory rate decreased with 250 microg/h of clonidine and larger doses. Sedation or incoordination occurred only at the largest dose for either drug. The safety study indicated that 3 mg/d of tizanidine in dogs produced no side effects or histopathologic changes. Tizanidine may be a useful alternative in patients experiencing cardiovascular side effects with intrathecal infusion of clonidine. ⋯ Clonidine is an effective spinal analgesic, but it is dose-limited by cardiovascular side effects. We compared the analgesic properties and side effects of clonidine with those of a similar drug, tizanidine. Continuous spinal infusion of tizanidine produced similar analgesia as clonidine, but with fewer adverse effects on blood pressure and heart rate.
-
The 1995 Tokyo subway strike proved nerve gas to be a fearsome terrorist weapon of mass destruction. Because the clear liquid is easily hidden until released, rescuers must aid nonbreathing casualties near instantly. Anesthesiologists are uniquely qualified to train these rescue squads and to manage nerve gas victims in the hospital.