Anesthesia and analgesia
-
Anesthesia and analgesia · Apr 2003
Randomized Controlled Trial Clinical TrialClinical results with the acoustic puncture assist device, a new acoustic device to identify the epidural space.
Sixty patients scheduled for lumbar epidural anesthesia were included in a study in which we evaluated the efficacy of localizing the epidural space by means of an acoustic signal. A prototype of an acoustic puncture assist device, connected to the epidural needle by an extension tube, generated the pressure needed to perform the epidural puncture and translated this pressure into corresponding acoustic and visible signals. The device frees the anesthesiologist to handle the epidural needle with both hands and to detect the epidural space by means of these signals. In all 60 patients (100%), the epidural space was successfully located by using the acoustic signal. In all cases, this was confirmed by the pressure measurement, which proved to be a reliable indicator for correct identification of the epidural space. We conclude that it is possible to locate the epidural space by means of the acoustic puncture assist device. The method proved to be reliable, safe, and simple in this study. The benefits of this new epidural puncture technique include better needle control, teaching, control of correct catheter placement, and documentation. The last can be an important adjunct to anesthesia practice. ⋯ The authors demonstrate that it is possible to identify the epidural space by an acoustic and visible signal. An experimental setup constructed for this purpose makes the epidural puncture procedure audible and visible.
-
Anesthesia and analgesia · Apr 2003
Randomized Controlled Trial Clinical TrialThe effect of epidural test dose on motor function after a combined spinal-epidural technique for labor analgesia.
Labor analgesia initiated with intrathecal bupivacaine and fentanyl, without a local anesthetic epidural test dose, provides effective analgesia and allows ambulation. In this study, we sought to determine the effect of a lidocaine-epinephrine test dose administered immediately after the initiation of combined spinal-epidural (CSE) analgesia with bupivacaine 2.5 mg and fentanyl 25 micro g on parturients' hemodynamic stability, posterior column function, motor strength, and subjective ability to walk. Parturients (n = 153) were randomized to receive either 3 mL of epidural saline or lidocaine 1.5% with epinephrine 1:200,000. Hemodynamic variables, proprioception, straight leg raise, and the modified Bromage score were analyzed in 110 parturients who completed the study protocol and were not different between groups. Vibratory sense, the ability to perform a partial deep knee bend and to step up on a stool, and the subjective ability to walk were impaired in a larger number of parturients in the lidocaine-epinephrine group at 30 min (P < 0.05). At 60 min, there were no differences between the groups except that fewer parturients in the lidocaine-epinephrine group could step up on a stool. The straight leg raise against resistance and the modified Bromage scale did not correlate well with other tests of motor strength (Spearman's rho, 0.273-0.405). These data suggest that the test dose should be avoided immediately after initiation of CSE analgesia when early ambulation is desired. ⋯ A lidocaine-epinephrine epidural test dose (3 mL of lidocaine 1.5% with epinephrine 1:200,000), injected immediately after the initiation of combined spinal-epidural labor analgesia with bupivacaine 2.5 mg and fentanyl 25 microg, may interfere with the ability to perform simple tests of motor function and ambulation.
-
Anesthesia and analgesia · Apr 2003
Comparative Study Clinical TrialA comparison of the PAxpress and face mask plus Guedel airway by inexperienced personnel after mannequin-only training.
The PAxpress (PAX) is a new extraglottic airway device consisting of an anatomically curved tube, an inflatable circular cuff in the midsection, a noninflatable gilled conical cuff at the distal end, and an anterior-facing, rectangular hooded vent between the two cuffs. We compared the ability of nurses with no previous airway management experience to ventilate the lungs of 45 ASA physical status I and II anesthetized, paralyzed patients using either the PAX or face mask and Guedel airway (FM/GA) after mannequin-only training. Nurses were asked to ventilate the patient to an expired target tidal volume of 7 mL/kg and then to the maximum tidal volume achievable. The FM/GA was used first and the then the PAX. The target tidal volume was achieved in all patients with both devices. There were no differences in the time taken (PAX, 41 +/- 15 s; FM/GA, 39 +/- 25 s) or the number of insertion attempts to achieve the target tidal volume. There were no differences in the frequency of esophageal leaks at the target (PAX, 9%; FM/GA, 4%) and maximum tidal volume (PAX, 51%; FM/GA, 49%). The maximal tidal volume (1261 +/- 306 versus 958 +/- 220 mL; P < 0.0001) and peak airway pressure (37 +/- 5 versus 28 +/- 6 cm H(2)O; P < 0.0001) was larger for the PAX, but blood was detected more frequently (22% versus 0%; P = 0.001). We conclude that ventilation to a target tidal volume of 7 mL/kg in anesthetized, paralyzed adults is equally successful for the PAX and FM/GA by inexperienced nurses after mannequin-only training. However, the maximal tidal volume and peak airway pressure is larger and airway trauma more common with the PAX. ⋯ Ventilation to a target tidal volume of 7 mL/kg in anesthetized, paralyzed adults is equally successful for the PAxpress (PAX) and Face Mask/Guedel Airway by inexperienced nurses after mannequin-only training. However, the maximal tidal volume and peak airway pressure is larger and airway trauma more common with the PAX.
-
Anesthesia and analgesia · Apr 2003
Clinical TrialPenetration of intravenous hydroxyethyl starch into the cerebrospinal fluid in patients with impaired blood-brain barrier function.
Hypovolemic patients with impairment of the blood-brain barrier may receive IV hydroxyethyl starch (HES) to stabilize cardiovascular function and to increase cerebral perfusion pressure. It is not known whether HES can penetrate into the cerebrospinal fluid (CSF) under those conditions. We investigated plasma and CSF levels of HES after IV infusion in patients with suspected disturbance of the blood-brain barrier. Eight adult patients were studied who were being treated for head trauma or subarachnoid hemorrhage, with an external CSF drain in place. All patients exhibited radiographic signs of blood-brain barrier impairment diagnosed by cerebral computed tomography. After IV infusion of 500 to 1000 mL of HES 200,000/0.5, plasma HES levels were measured. Additionally, all CSF that was drained within 8 h after the HES infusion was collected, and HES concentrations were measured. All patients had detectable HES plasma concentrations (3.41 to 9.95 mg/mL). In contrast, no HES could be detected in the CSF of any patient. These data indicate that IV HES 200,000/0.5 does not penetrate into the CSF in patients with disturbed blood-brain barrier function after subarachnoid hemorrhage or head trauma. Further study is required to determine whether HES penetrates into the intracranial interstitium, despite the absence of HES in the CSF. ⋯ Patients may receive IV hydroxyethyl starch (HES) after head trauma or subarachnoid hemorrhage. The results of the present study indicate that in patients with suspected blood-brain barrier impairment, HES does not penetrate from the plasma into the cerebrospinal fluid.
-
Anesthesia and analgesia · Apr 2003
Comparative StudyThe comparative effects of prostaglandin E1 and nicardipine on cerebral microcirculation in rabbits.
We compared the effects of the systemic hypotensive drugs prostaglandin E1 (PGE1) and nicardipine on the cerebral microcirculation and on the cerebrovascular reactivities to hypercapnia and hypoxia. In isoflurane-anesthetized rabbits (n = 48), we measured cerebral pial vessel diameters using a cranial-window preparation: (a) during IV PGE1- or nicardipine-induced mild or moderate hypotension (to 80% or 60% of initial mean arterial blood pressure), (b) after topical administration of these drugs, and (c) during hypercapnia or hypoxia induced during such mild or moderate hypotension. Pial arteriolar diameters were (a) unchanged when hypotension (mild or moderate) was induced by PGE1 but increased when it was induced by nicardipine and (b) increased dose-dependently by topical administration of nicardipine but not PGE1. Only small changes in cerebral venular diameter were observed in these experiments. The pial arteriolar dilator response to hypercapnia was potentiated during hypotension (mild or moderate) when it was induced by PGE1 but decreased when it was induced by nicardipine, whereas the response to hypoxia was maintained during PGE1-induced hypotension but decreased during nicardipine-induced hypotension. In conclusion, as a systemic hypotensive drug, PGE1 does not dilate cerebral arterioles and maintains cerebrovascular reactivities to hypercapnia and hypoxia, whereas nicardipine dilates such vessels and reduces these cerebrovascular reactivities. ⋯ When given systemically to produce mild or moderate hypotension, prostaglandin E1 does not induce cerebral vasodilation and maintains cerebrovascular reactivity to hypercapnia and hypoxia, whereas nicardipine dilates cerebral vessels and reduces both reactivities.