Anesthesia and analgesia
-
Anesthesia and analgesia · Mar 2005
Randomized Controlled Trial Clinical TrialEpidural ropivacaine anesthesia decreases the bispectral index during the awake phase and sevoflurane general anesthesia.
The sedative effects of epidural anesthesia without volatile and IV anesthetics and quantification of the degree of epidural anesthesia-induced sedation have not been investigated. In the current study we evaluated the effects of epidural anesthesia on the bispectral index (BIS) during the awake phase and during general anesthesia. After placing the epidural catheter, the patients were randomly allocated to 2 groups receiving either 5 mL of epidural saline (group S) or the same volume of 0.75% ropivacaine (group R). ⋯ The BIS during general anesthesia was significantly lower in group R than in group S (P < 0.0001). Epidural anesthesia decreased the BIS during the awake phase and during general anesthesia. The decrease of the BIS associated with epidural anesthesia was more prominent during general anesthesia than during the awake phase.
-
Anesthesia and analgesia · Mar 2005
Threshold current of an insulated needle in the intrathecal space in pediatric patients.
A threshold current of <1 mA has been suggested to be sufficient to produce a motor response to electrical stimulation in the intrathecal space. We designed this study to determine the threshold current needed to elicit motor activity for an insulated needle in the intrathecal space. Twenty pediatric patients aged 7.3 +/- 3.9 yr scheduled for lumbar puncture were recruited. ⋯ In 19 patients, the twitches were observed at the L4-5 myotomes and 1 patient had twitches at L2. Twitches were observed unilaterally in 19 children and bilaterally in one child. This confirms the hypothesis that the threshold current in the intrathecal space is <1 mA and that it differs significantly from the threshold currents reported for electrical stimulation in the epidural space.
-
Anesthesia and analgesia · Mar 2005
Cardiac arrest during neuraxial anesthesia: frequency and predisposing factors associated with survival.
The frequency and predisposing factors associated with cardiac arrest during neuraxial anesthesia remain undefined, and the survival outcome data are contradictory. In this retrospective study, we evaluated the frequency of cardiac arrest, as well as the association of preexisting medical conditions and periarrest events with survival after cardiac arrest during neuraxial anesthesia between 1983 and 2002. To assess whether survival after cardiac arrest differs for patients who arrest during neuraxial versus general anesthesia, data were also obtained for patients who experienced cardiac arrest under general anesthesia during similar surgical procedures during the same time interval. ⋯ Hospital survival was significantly improved for patients who arrested during neuraxial anesthesia versus general anesthesia (65% vs 31%; P = 0.013). The association of improved survival with neuraxial anesthesia remained statistically significant after adjusting for all patient/procedural characteristics, with the exception of ASA classification and emergency procedures. We conclude that a cardiac arrest during neuraxial anesthesia is associated with an equal or better likelihood of survival than a cardiac arrest during general anesthesia.
-
Anesthesia and analgesia · Mar 2005
The effects of propofol or sevoflurane on the estimated cerebral perfusion pressure and zero flow pressure.
The zero flow pressure (ZFP) is the pressure at which blood flow ceases through a vascular bed. Using transcranial Doppler ultrasonography, we investigated the effects of propofol or sevoflurane on the estimated cerebral perfusion pressure (eCPP) and ZFP in the cerebral circulation. Twenty-three healthy patients undergoing nonneurosurgical procedures under general anesthesia were studied. ⋯ The eCPP decreased significantly in the propofol group (median, from 58 to 41 mm Hg) but not in the sevoflurane group (from 60 to 62 mm Hg). Correspondingly, ZFP increased significantly in the propofol group (from 25 to 33 mm Hg) and it decreased significantly in the sevoflurane group (from 27 to 7 mm Hg). Hypocapnia did not change eCPP or ZFP in the propofol group, but it significantly decreased eCPP and increased ZFP in the sevoflurane group.
-
Anesthesia and analgesia · Mar 2005
The effect of venous pulsation on the forehead pulse oximeter wave form as a possible source of error in Spo2 calculation.
Reflective forehead pulse oximeter sensors have recently been introduced into clinical practice. They reportedly have the advantage of faster response times and immunity to the effects of vasoconstriction. Of concern are reports of signal instability and erroneously low Spo(2) values with some of these new sensors. ⋯ Further examination of the complex forehead wave form reveal a morphology consistent with a central venous trace with atrial, cuspidal, and venous waves. It is speculated that the presence of the venous signal is the source of the problems reported with the forehead sensors. It is believed that the venous wave form is a result of the method of attachment rather than the use of reflective plethysmographic sensors.