Anesthesia and analgesia
-
Anesthesia and analgesia · May 2004
Randomized Controlled Trial Clinical TrialAutomated cardiac output measurement by transesophageal color Doppler echocardiography.
Automated cardiac output measurement (ACOM), which integrates digital color Doppler velocities in space and in time, has been validated using transthoracic echocardiography but has not been tested using transesophageal echocardiography (TEE). Therefore, we determined the feasibility of the ACOM method by TEE in 36 patients undergoing cardiovascular surgery. Regions of interest for ACOM were placed within a color sector across the main pulmonary artery (PA), the mitral annulus, and the left ventricular outflow tract. Cardiac output was determined from the PA flow, the mitral flow, and the left ventricular ejection flow at each view using the ACOM method. We compared measurements of cardiac output derived from the ACOM method with measurements simultaneously obtained by thermodilution (TD). In the mitral flow analysis, the values derived from ACOM correlated well with those from TD (R(2) = 0.85; mean difference = 0.01 +/- 0.58 L/min in the 2-chamber view; R(2) = 0.78; mean difference = -0.10 +/- 0.68 L/min in the 4-chamber view). In the PA flow analysis, the values derived from ACOM did not correlate with those from TD (R(2) = 0.30). In the left ventricular outflow tract analysis, it was very difficult to obtain the optimal view (44%) in which color Doppler flow signals adequately appeared. Using the ACOM method, we obtained good correlation and agreement for cardiac output measurements in the mitral flow analysis compared with TD. The ACOM method is a practical and rapid method to measure cardiac output by TEE analysis of mitral flow. ⋯ Automated cardiac output measurement by transesophageal color Doppler echocardiography is a practical and rapid method to measure cardiac output. This technique is a promising new approach to echocardiographic quantification in the intraoperative setting.
-
Anesthesia and analgesia · May 2004
Case ReportsTransient vascular insufficiency after axillary brachial plexus block in a child.
Axillary block is used in children for procedures on the hand and forearm. We report on a child with an amputation of the thumb in whom an axillary block was given, after which the limb became pale and pulseless. The pulses returned spontaneously in 15 min. The awareness of this possibility and chances of spontaneous recovery should be considered. ⋯ Transient vascular insufficiency of the upper limb may happen as a rare complication after axillary block. Knowledge of this complication can help the anesthesiologist in the management of this problem.
-
We accomplished endotracheal intubation by using fluoroscopic direction in a patient presenting a difficult airway both on the basis of a preanesthetic physical examination and on the basis of a potential for cervical cord injury associated with complicated laryngoscopy. Under topical anesthesia, a multipurpose angiographic (MPA) catheter over a Bentson wire was advanced into the trachea under intermittent C-arm fluoroscopic guidance while the occiput, cervical spine, and mandible remained in a neutral position. The endotracheal tube was then easily advanced over the MPA catheter into the trachea, where the location was documented by fluoroscopic view. Because of judicious use of topical anesthesia and the small diameter and flexibility of the MPA catheter, the unsedated patient remained comfortable throughout the procedure. The stored data were later transferred to a compact disk, and a copy was provided to the patient as an adjunct to Medic-Alert. Unlike fiberoscopy, with which the view can be totally obscured by secretions, blood, and abnormal anatomy, the direction and location of the MPA catheter within the airway were easily identifiable throughout the procedure. The small diameter of the MPA (1.5-mm outer diameter) should allow placement of endotracheal tubes as small as 3.0-mm inner diameter--an option not available even with pediatric instruments. Although time was not a consideration, the procedure was accomplished in <12 min with 22 s of fluoroscopy. We believe that with experience, atraumatic intubation of a difficult airway could be accomplished routinely in less than 2 min with radiological-assisted intubation. ⋯ Radiologic-assisted intubation facilitated endotracheal intubation without sedation, instrumentation, or significant movement of the occiput, cervical spine, or mandible. The procedure was accomplished in <12 min and with only 22 s of fluoroscopy. This approach provides the ultimate adjunct to the preoperative airway physical evaluation while providing for immediate (or delayed) atraumatic endotracheal intubation. The diagnostic information and procedure can be recorded on a compact disk.
-
Anesthesia and analgesia · May 2004
A model for evaluating droperidol's effect on the median QTc interval.
Controversy surrounds the use of the antiemetic droperidol, because of the Food and Drug Administration-imposed "black box" warning alleging that even small doses of the drug can lead to serious (even fatal) arrhythmias when it is used for antiemetic prophylaxis during the perioperative period. We used mathematical modeling of electrocardiographic QT interval data published in a peer-reviewed manuscript to evaluate the relationship between the dose of droperidol (0.1-0.25 mg/kg i.v.) and QT(c) prolongation. In comparing the calculated QT(c) values based on the logarithm model (27-63 ms), the linear model (27-67 ms) and the square-root model (36-57 ms) to the actual measured QT(c) values (37-59 ms), the square-root model provided the best simulation of the experimental findings. Other models that we evaluated included the polynomial model and various exponent models (e.g., quartic-root model, cubic-root model, square model, and cubic model). The estimated median prolongation of the median QT(c) interval produced by droperidol 0.625-1.25 mg i.v. would vary from 9 +/- 3 to 18 +/- 3 ms. Therefore, this regression analysis suggests that small "antiemetic" doses of droperidol (< or =1.25 mg) would be unlikely to produce proarrhythmogenic effects in the perioperative period. ⋯ Using a square-root curve fit model to evaluate the relationship between the dose of droperidol and QT(c) prolongation, small-dose droperidol (0.625-1.25 mg i.v.) would be expected to produce <30-ms prolongation of the QT(c) interval. Therefore, small "antiemetic" doses of droperidol would not be expected to produce proarrhythmogenic effects when used for prophylaxis in surgical patients.
-
Anesthesia and analgesia · May 2004
Randomized Controlled Trial Comparative Study Clinical TrialThe short- and long-term benefit in chronic low back pain through adjuvant electrical versus manual auricular acupuncture.
Acupuncture is an established adjuvant analgesic modality for the treatment of chronic pain. Electrical stimulation of acupuncture points is considered to increase acupuncture analgesia. In this prospective, randomized, double-blind, controlled study we tested the hypothesis that auricular electroacupuncture (EA) relieves pain more effectively than conventional manual auricular acupuncture (CO) in chronic low back pain patients with insufficient pain relief (visual analogue scale [VAS] > or = 5) treated with standardized analgesic therapy. Disposable acupuncture needles were inserted in the auricular acupuncture points 29, 40, and 55 of the dominant side and connected to a newly developed battery-powered miniaturized stimulator worn behind the ear. Patients were randomized into group EA (n = 31) with continuous low-frequency auricular EA (1 Hz biphasic constant current of 2 mA) and group CO (n = 30) without electrical stimulation (sham-electroacupuncture). Treatment was performed once weekly for 6 wk, and in each group needles were withdrawn 48 h after insertion. During the study period and a 3-mo follow-up, patients were asked to complete the McGill questionnaire. Psychological well being, activity level, quality of sleep, and pain intensity were assessed by means of VAS; moreover, analgesic drug consumption was documented. Pain relief was significantly better in group EA during the study and the follow-up period as compared with group CO. Similarly, psychological well-being, activity, and sleep were significantly improved in group EA versus group CO, the consumption of analgesic rescue medication was less, and more patients returned to full-time employment. Neuropathic pain in particular improved in patients treated with EA. There were no adverse side effects. These results are the first to demonstrate that continuous EA stimulation of auricular acupuncture points improves the treatment of chronic low back pain in an outpatient population. ⋯ Continuous electrical stimulation of auricular acupuncture points using the new point stimulation device P-stim significantly decreases pain intensity and improves psychological well-being, activity, and sleep in chronic low back pain patients.