Search PubMed⌕ Search

Biomedical subjects

M C Norris

Publications and source records attributed to M C Norris.

At least 37 records · Page 2Linked to original sources
PubMed1996

The dermatomal spread of epidural bupivacaine with and without prior intrathecal sufentanil.

Clinicians often use a technique combining intrathecal sufentanil and epidural bupivacaine to provide labor analgesia. This study determines the effect of 27- or 24-gauge dural puncture and intrathecal sufentanil 10 micrograms on the dermatomal spread of epidural bupivacaine. Healthy laboring women received no dural puncture (n = 77) (no puncture group [NPG]) or dural puncture with a 27-gauge Whitacre needle (n = 33) or a 24-gauge Sprotte needle (n = 37) and intrathecal sufentanil 10 micrograms (dural puncture group [DPG]) before epidural injection of 13 mL bupivacaine 0.25%. More dermatomes were anesthetized in the DPG, 16.6 +/- 7.5 vs 13.6 +/- 6.6 in the NPG (P < 0.02). More patients in the DPG had sensory blockade T-4 or higher (17 of 70 DPG patients vs 8 of 77 NPG patients; P < 0.05). No patient in either group showed clinical evidence of respiratory compromise. In conclusion, epidural bupivacaine anesthetized more dermatomes when administered 104 +/- 42 min after dural puncture and intrathecal sufentanil 10 micrograms than when given without prior dural puncture and intrathecal injection.

Analgesia, Epidural↗
PubMed1996

Labour analgesia. A risk-benefit analysis.

The pain associated with labour can be severe. The ideal labour analgesic does not exist and systemic opioids provide little relief. Nausea, vomiting and sedation are common adverse effects of systemic opioids. Paracervical block can relieve only the pain of the first stage of labour. The duration of analgesia obtained using paracervical block is limited and repeat blocks increase the risk of direct fetal injection. Epidural analgesia effectively relieves labour pain. The insertion of an epidural catheter can provide continuous analgesia throughout labour. In addition, the catheter can be used to provide surgical anaesthesia, should operative delivery be required. Epidural local anaesthetics commonly produce maternal hypotension and motor blockade. However, opioids potentiate the effect of epidural local anaesthetics. Thus, concomitant epidural opioid injection allows the use of lower concentrations of local anaesthetics, decreasing the frequency and severity of hypotension and motor blockade. Epidural analgesia has other, potentially catastrophic, adverse effects but, with safe clinical practice, these problems are extremely rare. Intrathecal injection of opioids or local anaesthetics also effective labour analgesia. However, no single intrathecal drug or drug combination reliably provides analgesia for the duration of labour. Many clinicians use both intrathecal and epidural analgesia as a combined spinal-epidural technique. This approach provides the rapid onset of intrathecal drugs and the flexibility of continuous epidural block. Fetal heart rate decelerations occasionally follow the use of any of the above labour analgesic techniques. Most studies of the aetiology of fetal heart rate decelerations have focused on factors unique to each analgesic technique. However, the similar timing and appearance of fetal bradycardia suggests a common cause. Induction of maternal analgesia may transiently alter the balance between factors encouraging and inhibiting uterine contraction. A temporary increase in the uterotonic effects of endogenous or exogenous oxytocin may then produce a tetanic uterine contraction with subsequent decrease fetal oxygen delivery and resultant fetal bradycardia. Regardless of aetiology, these bradycardias are transient and should not produce maternal or fetal morbidity. Much controversy surrounds the effects of analgesia, especially epidural block, on the course and outcome of labour. Various studies have reported that epidural analgesia slows labour, increases the incidence of malposition of the fetal head, increases the need for forceps delivery and increases the risk of caesarean delivery. Most of the studies reporting these effects are retrospective and nonrandomised. More careful studies suggest that specific anaesthetic techniques (i.e. local anaesthetic-opioid mixtures) or obstetrical management can limit or eliminate these 'risks' of epidural labour analgesia.

Adult↗
PubMed1994

The incidence of herpes simplex virus labialis after cesarean delivery.

Epidural and subarachnoid opioids have been associated with the development of oral herpes simplex lesions. Because of this risk, some anesthesiologists avoid neuraxial morphine in parturients with a history of herpes simplex virus labialis. When we began using neuraxial opioids for analgesia after cesarean delivery, we did not see any increased incidence of facial lesions. To confirm this impression, we studied 357 consecutive parturients presenting for elective or emergent cesarean delivery between 1 December 1989 and 27 June 1990. The women received spinal, epidural, or general anesthesia. Two hundred and one women received either spinal or epidural morphine, the remaining 156 parturients received only systemic opioids for postoperative analgesia. An investigator saw each patient daily until discharge. Only 11 patients (3%) developed oral lesions while hospitalized. None of these women had severe lesions. Neuraxial morphine did not increase the risk of labial lesions significantly (3.5% vs. 2.6%). Despite published data to the contrary, we found no correlation between neuraxial morphine and the risk of facial herpes virus lesions in women after cesarean delivery. We offer patients the option of neuraxial morphine for analgesia after cesarean delivery despite any history of oral herpes lesions.

Journal Article↗
PubMed1994

Complications of labor analgesia: epidural versus combined spinal epidural techniques.

Both epidural and combined spinal epidural (CSE) analgesia can provide maternal pain relief during labor. Currently, there are few data comparing the risks and complications of these two techniques. We recorded the incidence and severity of anesthetic-related complications in 1022 laboring parturients. Ninety-eight women opted for either no or parenteral analgesia, 388 chose epidural, and 536 requested CSE analgesia. Women choosing CSE analgesia most often received an intrathecal injection of sufentanil 10 micrograms at the time of epidural catheter insertion. The epidural catheters were then dosed as needed as the intrathecal analgesia waned. Women who received CSE analgesia were more likely to itch (41.4% vs 1.3%) or complain of nausea (2.4% vs 1.0%) or vomiting (3.2% vs 1.0%) than those receiving solely epidural analgesia. Patients who requested only epidural analgesia were more likely to suffer an unintended dural puncture (4.2% vs 1.7%). Fewer than 10% developed hypotension with either technique. The risk of headache was the same with both anesthetics (4%-10%) and did not differ from the incidence of headache in women not receiving neuraxial analgesia (10%-14%). Six patients required epidural blood patch for moderate to severe postural headache. Four of these women suffered a dural puncture with the 18-gauge Hustead epidural needle. The other two women had reportedly uncomplicated epidural and CSE analgesia. These data suggest either neuraxial analgesic technique can safely relieve the pain of labor. CSE analgesia is a safe alternative to epidural analgesia for labor and delivery.

Adult↗
PubMed1994

Spinal opioid analgesia for labor.

Intrathecal opioids and the combined spinal/epidural technique provide new tools for the obstetrical anesthesiologist. With intrathecal opioids, we can rapidly and safely relieve the pain of labor without maternal sedation or motor blockade. Intrathecal sufentanil 10 micrograms provides 1 to 2 hours of excellent analgesia during the first stage of labor. We often use this technique in women who would otherwise obtain marginal pain relief from systemic opioids. Unless morphine is used, the side effects induced by intrathecal opioids are usually mild and easily treated. In our practice, combined spinal/epidural labor analgesia has rapidly gained wide acceptance by patients, nurses, obstetricians, and anesthesiologists. Continuous spinal analgesia, although theoretically appealing, requires further refinement.

Analgesia, Epidural↗
PubMed1993

Intrathecal sufentanil labor analgesia: the effects of adding morphine or epinephrine.

Intrathecal opioids can provide labor analgesia. We attempted to prolong the duration of intrathecal sufentanil analgesia by adding epinephrine or morphine. Forty-one healthy, term nulliparae with cervical dilation < 5 cm participated in this double-blind, randomized protocol. Using a combined spinal and epidural technique, we gave intrathecal injections of either sufentanil 10 micrograms, sufentanil 10 micrograms plus epinephrine 200 micrograms, or sufentanil 10 micrograms plus morphine 250 micrograms. At baseline and every 5 min for 30 min thereafter, we recorded arterial blood pressure and asked the patients to rate their pain, nausea, and pruritus on visual analog scales. The women continued to rate these variables every 30 min until they requested additional analgesia. They then received 10 mL of 0.25% bupivacaine via the epidural catheter, and rated the above variables every 30 min until they requested additional epidural drug injection. Both morphine and epinephrine prolonged the duration of sufentanil analgesia. Only morphine prolonged analgesia after the first dose of epidural bupivacaine. However, because women in the morphine group experienced significantly more side effects throughout the study period, we do not recommend intrathecal morphine for labor analgesia.

Adult↗
PubMed1992

Intrathecal meperidine for labor analgesia: preliminary communication.

The authors administered intrathecal meperidine 10 mg to 10 healthy laboring women to determine its analgesic quality, onset, duration, and side-effect profile. When patients requested pain relief, we injected 10 mg preservative-free meperidine in 1 ml normal saline through a 32 gauge spinal catheter. We administered a second dose of meperidine 10 mg if analgesia was inadequate at 10 min. Additional doses of intrathecal meperidine or bupivacaine were administered on request. All patients received local anesthetic intrathecally or by infiltration for delivery. Eight patients were pain-free following meperidine 10 mg, the other 2 patients were comfortable after the second 10 mg meperidine dose. Three patients did not request further labor analgesics and delivered 58, 66 and 244 min following their initial injection of intrathecal meperidine. The mean duration of analgesia in the other 7 patients was 136 +/- 58 (mean +/-SD) min. Six of the 10 women in the study delivered vaginally; 3 spontaneously and 3 with vacuum or forceps assistance. Four patients delivered by cesarean section for failure to progress. Side-effects (which were easily treated) consisted of: pruritus (n = 1), vomiting (n = 2), hypotension (n = 2) and changes in fetal heart rate pattern (n = 5). All infants were vigorous and had good Apgar scores at birth. In conclusion, intrathecal meperidine is a promising labor analgesic, but the effect of meperidine on maternal blood pressure, fetal heart rate pattern, and the progress of labor need to be determined.

Journal Article↗
PubMed1992

Comparison among intrathecal fentanyl, meperidine, and sufentanil for labor analgesia.

This study compared the analgesic efficacy of intermittent injections of intrathecal fentanyl (10 micrograms), meperidine (10 mg), or sufentanil (5 micrograms) administered to 65 parturients during the first stage of labor. The groups did not differ in onset or duration of effective analgesia. The meperidine group, however, had significantly lower pain scores once cervical dilation progressed beyond 6 cm. Side effects included mild pruritus and nausea. After intrathecal drug injection, variable decelerations of the fetal heart rate increased in the fentanyl and meperidine groups. All neonates had a 5-min Apgar score of 7 or more. We conclude that intermittent intrathecal injections of fentanyl, meperidine, or sufentanil can provide adequate first-stage labor analgesia. Meperidine appears to provide more reliable analgesia as the first stage of labor progresses.

Adult↗
PubMed1991

Histamine release following intrathecal administration of morphine for cesarean section.

We present a case of unusually profound, prolonged hypotension after induction of spinal anesthesia for cesarean section. The patient, a healthy parturient at 26 weeks gestation, received 0.75% bupivacaine, 15 mg and morphine, 0.15 mg by subarachnoid injection. Systolic blood pressure rapidly fell to below 80 mmHg despite left uterine displacement, 10 l of balanced saline solution, ephedrine 210 mg and phenylephrine 1000 microg. At the end of the operation we noted a pruritic, erythematous, circumscribed, raised rash, consistent with urticaria, over the patient's trunk, legs, arms and face. This rash persisted for 2 days. We postulate that the excessive hypotension following spinal anesthesia in this parturient was the result of intrathecal morphine induced histamine release.

Journal Article↗
PubMed1990

Patient variables and the subarachnoid spread of hyperbaric bupivacaine in the term parturient.

To determine if age, height, weight, body mass index, or vertebral column length significantly influence the distribution of sensory analgesia or anesthesia after subarachnoid injection of hyperbaric bupivacaine, 52 women presenting for cesarean section were studied. All received 15 mg hyperbaric bupivacaine via subarachnoid injection at L-2 or L-3. Fifteen minutes after injection, while the women lay supine on a horizontal operating table, the maximum cephalad extent of sensory analgesia (loss of sensation of sharpness to pin prick) and anesthesia (loss of sensation of light touch) was determined. Age (20-42 yr), height (146.9-174.0 cm), weight (55.5-136.4 kg), body mass index (19.2-50.0 kg/m2), and vertebral column length (49.6-67.0 cm) did not correlate with the spread of sensory blockade. In conclusion, in parturients of age, height, weight, body mass index, and vertebral column length within the aforementioned ranges, it is not necessary to vary the dose of injected hyperbaric bupivacaine with changes in any of the patient variables studied.

Adult↗
PubMed1990

The air test as a clinically useful indicator of intravenously placed epidural catheters.

The authors performed a clinical trial in 313 patients in labor to determine the safety and efficacy of an air test for unintentional intravenous placement of epidural catheters. Following routine aspiration for blood and cerebrospinal fluid, 1 ml of air was injected through each epidural catheter while heart tones were continually monitored with a Doppler ultrasound probe placed over the maternal precordium. In 281 patients, Doppler heart tones did not change following air injection (negative air test). All but eight of these patients developed an adequate level of analgesia following anesthetic administration, and no patients with negative air tests developed signs or symptoms of local anesthetic toxicity (false-negative rate, 0%; 95% confidence limits, 0.0-1.1%). Doppler heart tone changes followed air injection in 22 cases (positive air test). In 16 of these, intravenous catheter position was subsequently shown by aspiration of blood from the catheter or by the use of test doses consisting of local anesthetics with or without epinephrine. In six cases, adequate levels of analgesia developed despite a positive air test (false-positive rate, 2%; 95% confidence limit, 0.7-4.3%). None of the 303 patients receiving the air test developed any complications attributable to the injection of air (95% confidence limits, 0.0-1.0%). The authors conclude that air, with precordial Doppler detection, is a safe and effective test for identifying intravenously located epidural catheters.

Air↗