ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

BackgroundSome studies suggest that epidural analgesia prolongs labor and increases the incidence of cesarean section, especially if it is administered before 5 cm cervical dilation. The purpose of the current study was to determine whether early administration of epidural analgesia affects obstetric outcome in nulliparous women who are receiving intravenous oxytocin.MethodsInformed consent was obtained from healthy nulliparous women with a singleton fetus in a vertex presentation, who requested epidural analgesia while receiving intravenous oxytocin at at least 36 weeks' gestation. Each patient was randomized to receive either early or late epidural analgesia. Randomization occurred only after the following conditions were met: (1) the patient requested pain relief at that moment, (2) a lumbar epidural catheter had been placed, and (3) the cervix was at least 3 but less than 5 cm dilated. Patients in the early group immediately received epidural bupivacaine analgesia. Patients in the late group received 10 mg nalbuphlne intravenously. Late-group patients did not receive epidural analgesia until they achieved a cervical dilation of at least 5 cm or until at least 1 h had elapsed after a second dose of nalbuphine.ResultsEarly administration of epidural analgesia did not prolong the interval between randomization and the diagnosis of complete cervical dilation, and it did not increase the incidence of malposition of the vertex at delivery. Also, early administration of epidural analgesia did not result in an increased incidence of cesarean section or instrumental vaginal delivery. Thirteen (18%) of 74 women In the early group and 14 (19%) of 75 women in the late group underwent cesarean section (relative risk for the early group 0.94; 95% confidence interval 0.48–1.84). Patients in the early group had lower pain scores between 30 and 120 min after randomization, and were more likely to experience transient hypotension. Infants in the late group had lower umbilical arterial and venous blood pH and higher umbilical arterial and venous blood carbon dioxide tension measurements at delivery.ConclusionsEarly administration of epidural analgesia did not prolong labor or increase the incidence of operative delivery, when compared with intravenous nalbuphine followed by late administration of epidural analgesia, in nulliparous women who were receiving intravenous oxytocin.

ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

BackgroundSome studies suggest that epidural analgesia prolongs labor and increases the incidence of cesarean section, especially if it is administered before 5 cm cervical dilation. The purpose of the current study was to determine whether early administration of epidural analgesia affects obstetric outcome in nulliparous women who are in spontaneous labor.MethodsInformed consent was obtained from 344 healthy nulliparous women with a singleton fetus in a vertex presentation, who requested epidural analgesia during spontaneous labor at at least 36 weeks' gestation. Each patient was randomized to receive either early or late epidural analgesia. Randomization occurred only after the following conditions were met: (1) the patient requested pain relief at that moment, (2) a lumbar epidural catheter had been placed, and (3) the cervix was at least 3 cm but less than 5 cm dilated. Patients in the early group immediately received epidural bupivacaine analgesia. Patients in the late group received 10 mg nalbuphlne intravenously. Late-group patients did not receive epidural analgesia until they achieved a cervical dilation of at least 5 cm or until at least 1 h had elapsed after a second dose of nalbuphine. Ten of the 344 patients were excluded because of a protocol violation or voluntary withdrawal from the study.ResultsEarly administration of epidural analgesia did not increase the incidence of oxytocin augmentation, prolong the interval between randomization and the diagnosis of complete cervical dilation, or increase the incidence of malposition of the vertex at delivery. Also, early administration of epidural analgesia did not result in an increased incidence of cesarean section or instrumental vaginal delivery. Seventeen (10%) of 172 women in the early group and 13 (8%) of 162 women in the late group underwent cesarean section (relative risk for the early group 1.22; 95% confidence interval 0.62–2.40). Patients in the early group had lower pain scores between 30 and 150 min after randomization. Infants in the late group had lower umbilical arterial and venous blood pH and higher umbilical venous blood carbon dioxide tension measurements at delivery.ConclusionsEarly administration of epidural analgesia did not prolong labor, increase the incidence of oxytocin augmentation, or increase the incidence of operative delivery, when compared with intravenous nalbuphlne followed by late administration of epidural analgesia, in nulliparous women who were in spontaneous labor at term.

ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

BackgroundAlthough intrathecal sufentanil has been reported to provide rapid-onset, complete analgesia lasting 1–3 h for the first stage of labor, no well-controlled double-blind study has compared this technique to the use of epidurally administered local anesthetics.MethodsFifty healthy parturient women requesting labor analgesia were studied. In a combined spinal-epldural technique, a spinal needle was inserted through the epidural needle before insertion of the epidural catheter. Patients were randomly assigned to receive either intrathecal sufentanil (10 μg) and epidural saline, or intrathecal saline and epidural bupivacaine (30 mg). Visual analog scores for pain, blood pressure, heart rate, sensory levels, and the incidence of nausea, pruritus, and motor blockade were recorded.ResultsPatients receiving intrathecal sufentanil had significantly lower visual analog pain scores at 5, 15, and 30 min after injection and a greater duration of analgesia before requesting additional medication (mean 123 vs. 68 min for those receiving bupivacaine; P < 0.05). These patients also experienced pruritus more frequently but motor blockade less frequently than patients receiving epidural bupivacaine. The groups exhibited dermatomal sensory deficits to pin prick as well as bradycardia and hypotension with equal frequency. The length of labor and type of delivery were similar between the groups. No patient experienced a post-dural puncture headache.ConclusionsThe rapid onset of analgesia and lack of motor blockade from intrathecal sufentanil injection may be advantageous in certain clinical situations. With this technique, however, pruritus is common; hypotension may occur; and extensive dermatomal spread suggests that early-onset respiratory depression could occur. Therefore, blood pressure and respiratory adequacy should be monitored if intrathecal sufentanil is used.

ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Backgroundα2-Adrenergic agonists such as dexmedetomidine can be used to reduce the dose requirement of intravenous and volatile anesthetics. Whereas dexmedetomidine and volatile anesthetics interact pharmacodynamically (reduction of MAC), the mechanism of interaction between dexmedetomidine and intravenous anesthetics is not known.MethodsFourteen male ASA physical status 1 patients were randomly assigned to serve as control subjects (n = 7) or to be treated with dexmedetomidine (n = 7; 100, 30, and 6 ng. kg−1. min−1for 10 min, 15 min, and thereafter, respectively). After 35 min, in all patients, thiopental (100 mg/min) was infused until burst suppression appeared in the raw tracing of the electroencephalogram. By using concentrations of thiopental in plasma and the electroencephalogram as a continuous pharmacologic effect measure, the apparent effect site concentrations for thiopental were estimated in both groups. Three-compartment pharmacokinetics were calculated for thiopental.ResultsDexmedetomidine reduced the thiopental dose requirement for electroencephalographic burst suppression by 30%. There was no difference in estimated thiopental effect site concentrations between dexmedetomidine and control patients, suggesting the absence of a major pharmacodynamic interaction. Dexmedetomidine significantly decreased distribution volumes (V2, V3, and Vdss) and distribution clearances (Cl1Zand Cl13) of thiopental.ConclusionsThe thiopental dose-sparing effect of dexmedetomidine on the electroencephalogram is not the result of a pharmacodynamic interaction but rather can be explained by a dexmedetomidlne-lnduced decrease in thiopental distribution volume and distribution clearances. Dexmedetomidine reduces thiopental distribution, most probably by decreasing cardiac output and regional blood flow.

ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

BackgroundControversy exists regarding the definition of masseter muscle rigidity (MMR) and anesthetic management after MMR. This study reports current anesthetic management after MMR, estimates the incidence of clinical malignant hyperthermia (MH) in patients with MMR, and is the first to evaluate the coincidence of MMR with malignant hyperthermla susceptibility (MHS) according to the 1987 North American Malignant Hyperthermia Group protocol.MethodsPracticing anesthesiologists referred pediatric patients for biopsy between 1986 and 1991 based on evidence of MMR after succinylcholine (1975–1991). The clinical scenario was described as MMR alone or MMR followed by signs of MH, including arterial CO2tension > 50 mmHg, arterial pH ± 7.25, and base deficit > 8. Patients had caffelne-halothane muscle contracture testing to determine MHS.ResultsSeventy patients (50 boys and 20 girls) were evaluated. Eighty-three percent (58 of 70) of anesthetics were halothane-succinylcholine. In 68% (48 of 70) of cases, the anesthetic was discontinued, whereas anesthesia was continued with nontriggering agents in 11% (8 of 70) and with triggering agents in 13% (9 of 70). Fifty-nine percent (41 of 70) of patients were diagnosed as MHS by muscle biopsy. In 7% (5 of 70) of patients, clinical MH developed within 10 min of MMR.ConclusionsThis study, by using the current North American Malignant Hyperthermla Group protocol, reaffirms the high incidence (59%, 41 of 70) of MHS associated with MMR as confirmed by muscle biopsy. Of the MHS patients, 5 developed signs of clinical MH. Most anesthesiologists in this study, when confronted with MMR, discontinued anesthesia. Because of the potential lethality of MH and the > 50% concordance between MMR and MHS, the most conservative course of action after MMR is to discontinue the anesthetic and observe the patient for clinical evidence of MH. An acceptable alternative, depending on the urgency of the surgery, would be to continue anesthesia with nontriggering agents for MH, with appropriate monitoring.

ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

BackgroundContinuation of intrathecal anesthesia into the postoperative period has been limited by important safety concerns. Principal among these has been the assumption that extended intrathecal therapy leads to spinal (epidural and intrathecal) space infections. To address the role of extended intrathecal catheter therapy as a cause of infections, we cultured all intrathecal catheters used to provide postoperative analgesia.MethodsAll intrathecal catheters were inserted in the operating room using sterile technique. The catheters were used either for the duration of the patients stay in the intensive care unit or until they were no longer judged to provide a therapeutic advantage. They were removed without skin preparation. The distal 2–3 cm of the catheters was cultured using semiquantitative culture methods. Results were divided into four groups: group 1, negative culture results; group 2, ten or fewer colonies of growth; group 3, more than 10 colonies on initial plates and/or growth from broth cultures; and group 4, any bacterial growth, along with evidence of local or central nervous system infections.ResultsCultures were obtained from 139 patients with a mean Indwelling catheter time of 66.1 h. Group 1 (102 patients) had a mean indwelling duration of 55 h. Group 2 (26 patients) and group 3 (11 patients) had significantly longer indwelling duration (83.2 h P =.0023, 129.6 h P = <.0001, respectively) than group 1. Cultures of cerebrospinal fluid obtained simultaneously with catheter cultures in 9 cases (5 in group 2 and 4 in group 3) showed no growth. No patient had evidence of local or central nervous system infection. Difficulty of catheter placement (number of attempts made and the number of levels explored), antibiotic administration, the composition of the postoperative infusions and the number of catheter breaks in the postoperative period were similar in each group. With the exception of two catheters in group 3, (cultured at 49 and 54 h), significant bacterial growth (more than ten colonies) was observed only after more than 96 h of indwelling duration.ConclusionsApplication of semiquantitative culture methods assisted in explaining the results seen in group 2 as secondary to contamination of the catheter that occurred on removal. Higher numbers of bacteria (group 3) may define a population at increased risk for infectious complications. The results of this study do not absolutely resolve the issue of infectious risk associated with postoperative intrathecal catheter use, nor do they define a safe period beyond which the risk of continued catheter use would be unacceptable. However, it appears that limited periods of use (96 h or less) is not associated with either frequent local or spinal infections. Semiquantitative culture methods may help identify individuals (with catheter cultures yielding more than ten colonies) at increased risk for infectious complications and in need of closer observation.

ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

BackgroundRocuronium, like other steroidal nondepolarizing muscle relaxants, may in part be eliminated by the liver. To determine the influence of liver disease on its neuromus-cular blocking effect, we studied the pharmacokinetics and pharmacodynamics of rocuronium in patients with cirrhosis.MethodsEighteen patients undergoing elective surgery, 10 with cirrhosis and 8 with normal liver function, were studied. Anesthesia was induced with Intravenous thiopental 5–7 mg. kg−1and maintained with 60% nitrous oxide in oxygen and repeated doses of fentanyl 2 μg. kg−1. The force of thumb adduction in response to supramaximal ulnar nerve stimulation was monitored and recorded. An intravenous bolus of rocuronium 0.6 mg. kg−1was administered and venous blood sampled at frequent intervals for 6 h. Plasma concentrations of rocuronium was measured by high-pressure liquid chromatography. Data were fitted to both a pharmacokinetic and a pharmacodynamic model by using a two-compartment open model and an effect compartment model. Data were analyzed by least-squares regression.ResultsThe onset of neuromuscular blockade was longer (P >< 0.01) in patients with cirrhosis (158 ± 56 s) than in normal patients (108 ± 33 s). Recovery of the thumb twitch to 75 and 90% of its control value was 77 ± 25 and 88 ± 29 min in cirrhotic patients versus 57 ± 11 and 64 ± 13 mln, respectively, in normal patients (P < 0.05). The central volume of distribution of rocuronium was 104 ± 21 in cirrhotic patients and 78 ± 24 ml. kg−1in normal patients (P < 0.05). No significant difference in elimination kinetics was observed between the two groups. The elimination half-life was 87.5 ± 17.5 mln in normal patients and 96.0 ± 36.8 min in cirrhotic patients (difference not significant). This increased onset time was linearly correlated to the increased central volume of distribution of rocuronium in cirrhosis.ConclusionRocuronium onset time is longer in cirrhotic patients than in those with normal liver function; this can be explained by an increase in the volume in which rocuronium initially distributes. Although elimination kinetics are unchanged in patients with cirrhosis, rocuronium recovery time is prolonged in cirrhotic patients.

ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

BackgroundFor a newborn requiring positive-pressure ventilation (PPV), the American Heart Association recommends bag-and-mask ventilation, a challenging procedure for those inexperienced in neonatal resuscitation. The objective of this prospective study was to evaluate the laryngeal mask airway (LMA) as an alternative method of airway management in neonates requiring PPV at birth.MethodsWith the approval of the institutional ethics committee, consent was obtained from women in labor at a tertiary care-perinatal center. Inclusion criteria consisted of an expected birth weight of at least 2.5 kg, gestational age of at least 35 weeks, and resuscitation requiring PPV. Neonates meeting these criteria were resuscitated with PPV by means of the LMA. The ease of insertion, number of attempts required, time to establish effective ventilation, skin color, heart rate, respiratory effort, and Apgar scores were recorded.ResultsAttendance by the investigators at delivery was achieved in 93 cases, with 21 meeting the inclusion criteria. In all cases, the LMA was successfully inserted on the first attempt and provided a clinically patent airway. Twenty neonates were successfully resuscitated with the LMA to provide PPV, with no complications directly attributable to its use. One neonate required LMA removal and tracheal intubation to facilitate administration of epinephrine; data from this case was removed from the study.ConclusionsProviding PPV at birth via a size-1 LMA is effective and easily learned by personnel with expertise in neonatal resuscitation. The LMA should be further assessed as an alternative to bag-and-mask ventilation for this purpose.

ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID