Anesthesia and analgesia
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Anesthesia and analgesia · May 1998
Randomized Controlled Trial Clinical TrialThe effect of epinephrine on small-dose hyperbaric bupivacaine spinal anesthesia: clinical implications for ambulatory surgery.
The effect of adding epinephrine to small doses of spinal bupivacaine on the duration of sensory motor block has not been carefully investigated. Twelve volunteers underwent hyperbaric bupivacaine spinal anesthesia (7.5 mg) with and without epinephrine (0.2 mg) in a randomized, double-blind, cross-over fashion. Sensory block was assessed with pinprick, transcutaneous electrical stimulation (TES) equivalent to surgical stimulation (at umbilicus, pubis, knee, and ankle), and tolerance of a pneumatic thigh tourniquet. Motor block was assessed with isometric force dynamometry. Discharge criteria were defined as return of pinprick sensation to dermatome S2, ability to ambulate, and ability to urinate. Extent of sensory block to pinprick over time was unaffected by the addition of epinephrine. However, epinephrine prolonged tolerance of TES at the pubis, knee, and ankle (33-48 min, P < 0.05) and of thigh tourniquet (30 min, P < 0.01). Motor block was prolonged by epinephrine at the quadriceps and gastrocnemius muscles (by 23 and 51 min, respectively, P < 0.002). Achievement of discharge criteria was prolonged by 48 min by the addition of epinephrine (P < 0.01). Thus, epinephrine may prolong surgical anesthesia for lower abdominal and lower extremity surgery and delay time until patients achieve discharge criteria. ⋯ Using a cross-over study design, 12 volunteers underwent bupivacaine spinal anesthesia with and without epinephrine. This study suggests that adding epinephrine to bupivacaine may prolong surgical anesthesia and also delay patients' discharge.
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Anesthesia and analgesia · May 1998
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of patient-controlled analgesia with lornoxicam versus morphine in patients undergoing lumbar disk surgery.
The analgesic efficacy and tolerability of lornoxicam (Xefo; Nycomed Pharma A/S, Roskilde, Denmark), a new nonsteroidal antiinflammatory drug, was compared with that of morphine in a double-blind, randomized, parallel-group study of 96 patients with at least moderate pain after lumbar microsurgical discectomy. Both drugs were administered i.v. via a patient-controlled analgesia (PCA) for up to 24 h postoperatively. Efficacy was assessed by comparing mean hourly pain intensity differences, mean hourly pain relief, and total pain relief (TOTPAR) values derived from a 5-point verbal rating scores of pain intensity and pain relief at several time points over 24 h. Of 79 patients included in a per-protocol analysis, statistically significant equivalence of lornoxicam and morphine was shown by TOTPAR values of 31.6 and 28.9, respectively (P = 0.048). Trends toward slightly faster onset of analgesia with morphine and slightly greater PCA demands with lornoxicam were observed initially, which may partly have been due to a higher baseline pain intensity in the lornoxicam group. Lornoxicam caused fewer adverse events than morphine (21.7% vs 38.0% of patients, respectively), most of which were mild or moderate in severity. These results suggest that lornoxicam is an alternative to morphine when administered by PCA for the treatment of moderate to severe postoperative pain. ⋯ After surgery for lumbar disk disease, patients obtained statistically equivalent pain relief with lornoxicam and morphine when administered by patient-controlled analgesia. However, lornoxicam was associated with a lower incidence of adverse events. This study suggests that lornoxicam provides an alternative to morphine for the treatment of postoperative pain.
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Anesthesia and analgesia · May 1998
Randomized Controlled Trial Clinical TrialSimulation of an epidural test dose with intravenous epinephrine in sevoflurane-anesthetized children.
An epidural test dose containing small doses of epinephrine does not produce a reliable increase in heart rate (HR) in children under halothane anesthesia. Because sevoflurane is increasingly used in clinical practice, we designed the present study to determine the hemodynamic responses to, and efficacy of, a simulated IV test dose containing a small dose of epinephrine in sevoflurane-anesthetized children. Sixty ASA physical status I infants and children (4.1 +/- 2.5 yr) undergoing elective minor surgeries were studied during 1.0 minimum alveolar anesthetic concentration of sevoflurane and 60% nitrous oxide in oxygen. The patients were randomly assigned to receive either saline (n = 15), a test dose consisting of 1% lidocaine (0.1 mL/kg) with 1:200,000 epinephrine (0.5 microg/kg, n = 15), atropine 0.01 mg/kg followed 5 min later by saline (n = 15), or atropine followed by the test dose (n = 15) via a peripheral vein to simulate intravascular injection of the epidural test dose. HR and systolic blood pressure were recorded every 15 and 30 s, respectively. The test dose increased the HR from 15 to 60 s and from 15 to 90 s without and with atropine, respectively. Mean maximum increases in HR were similar with and without atropine (21 +/- 8 and 22 +/- 6 bpm, respectively). Of 15 children, 7 and 5 developed HR changes < 20 bpm after the test dose with and without atropine, respectively, whereas all children who received saline had an increase in HR < 20 bpm. No dysrhythmia occurred during the study. Our results indicate that an epidural test dose containing epinephrine is unreliable based on the conventional HR criterion (positive if > or = 20 bpm increase), but reliable on the modified HR criterion (positive if > or = 10 bpm increase) in children anesthetized with sevoflurane. I.v. atropine before the test dose injection did not improve the efficacy based on the conventional HR criterion. Because test doses of epinephrine-containing solution are used to determine whether an epidural catheter is intravascular, it is important to define the optimal test dose under sevoflurane anesthesia. ⋯ We found that during sevoflurane anesthesia in children, a heart rate increase > or = 10 bpm and a systolic blood pressure increase > or = 15 mm Hg, when preceded by atropine, may be reliable indicators for detecting intravascular injection.
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Anesthesia and analgesia · May 1998
Comparative StudyA comparison of awake versus paralyzed tracheal intubation for infants with pyloric stenosis.
This prospective, nonrandomized, observational study of 76 infants with pyloric stenosis was conducted at an academic children's hospital and compared awake versus paralyzed tracheal intubation in terms of successful first attempt rate, intubation time, heart rate (HR) and arterial hemoglobin oxygen saturation (SpO2) changes, and complications. Three groups were determined by intubation method: awake (A) with an oxygen-insufflating laryngoscope, after rapid-sequence induction (R), or after modified rapid-sequence induction (M) including ventilation through cricoid pressure. Successful first attempt intubation rate was 64% for Group A versus 87% for paralyzed Groups R and M (P = 0.028). Median intubation time was 63 s in Group A versus 34 s in Groups R and M (P = 0.004). Transient, mild decreases in mean HR and SpO2 and incidences of significant bradycardia and decreased SpO2 did not vary by group. Complications, including bronchial or esophageal intubation, emesis, and oropharyngeal trauma, were few. Senior anesthesiologists intervened in four tracheal intubations. We advocate anesthetized, paralyzed tracheal intubation because struggling with conscious infants takes longer, often requires multiple attempts, and prevents neither bradycardia nor decreased SpO2. After induction, additional mask ventilation with O2 confers no advantage over immediate tracheal intubation in preserving SpO2. ⋯ In our children's hospital, awake tracheal intubation was not superior to anesthetized, paralyzed intubation in maintaining adequate oxygenation and heart rate or in reducing complications, and should be abandoned in favor of the latter technique for routine anesthetic management of otherwise healthy infants with pyloric stenosis.
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Anesthesia and analgesia · May 1998
Tests to evaluate intravenous placement of epidural catheters in laboring women: a prospective clinical study.
We prospectively evaluated the diagnostic accuracy of an epinephrine-containing epidural test dose (EpiTD) as a marker of intravascular injection in 209 unmedicated laboring women. Maternal heart rate (MHR) was continuously monitored and recorded on a strip chart. A tocodynamometer monitored uterine activity. A lumbar epidural catheter was placed and aspirated. If aspiration was positive for blood or cerebrospinal fluid (CSF), the catheter was replaced. In uterine diastole and with stable MHR, 198 patients received an EpiTD (epinephrine 15 microg plus lidocaine 45 mg) via the catheter. MHR and the generated HR strip were observed. A positive EpiTD was defined as a sudden increase in MHR of 10 bpm more than the resting MHR, within one minute after the injection, with a fast acceleratory phase of more than 1 bpm. Absence of a tachycardiac response suggested a negative EpiTD. If the tachycardiac response was deemed equivocal or a uterine contraction followed the EpiTD injection within 1 min, the EpiTD was invalidated and repeated. Catheter aspiration was repeated, and the catheter was removed if aspiration was positive. All patients with negative EpiTD and aspiration received 6-12 mL of epidural bupivacaine 0.25% with or without fentanyl 50 microg. Absence of analgesia without signs or symptoms of systemic toxicity after a maximum of bupivacaine 30 mg defined failed epidural analgesia. All patients with positive EpiTD and negative aspiration received 5 mL of lidocaine 2% epidurally as a second test dose (Lido100TD). The presence of tinnitus and/or metallic taste defined a positive Lido100TD. There were 176 true negatives, 0 false negatives, 14 true positives, and 8 false positives. The sensitivity of EpiTD was 100%, the specificity 96%, the negative predictive value 100%, and the positive predictive value 63%. The prevalence of negative tests was 88%, and the prevalence of positive tests was 12%. The overall accuracy of an EpiTD was 95.5%. We conclude that EpiTD is a reliable test to identify i.v. catheters during the performance of lumbar epidural analgesia in laboring patients. ⋯ Catheters inserted for epidural analgesia in laboring patients may accidentally enter a blood vessel. Local anesthetics injected through these catheters may cause seizures and cardiac arrest. In this study, we concluded that injecting a small amount of epinephrine before injecting a local anesthetic frequently helps to identify these misplaced catheters. Few catheters may actually be in the correct place even after responses to epinephrine.