Janna Blanchard

Intravenous regional sympatholysis: A double-blind comparison of guanethidine, reserpine, and normal saline

This double-blind, randomized study was designed to compare the effectiveness of intravenous regional sympatholysis using guanethidine, reserpine and normal saline. Twenty-one patients with reflex sympathetic dystrophy of an upper or lower extremity were enrolled and received intravenous regional blockade (IVRB) with one of the three medications. There was significant pain relief in all three groups at 30 min. There were no significant differences among the three groups in the degree of pain relief, the number of patients obtaining pain relief in the 30 min after the block, or the number of patients reporting more than 50% pain relief for more than 24 hr. The saline groups high rate of pain relief could be partially due to a mechanism of tourniquet-induced analgesia.

Plasma concentrations of ropivacaine given with or without epinephrine for brachial plexus block

The purpose of this study was to determine the pharmacokinetic properties of the local anaesthetic ropivacaine used with or without epinephrine for brachial plexus block. Seventeen ASA physical status I or II adult patients undergoing elective orthopaedic surgery received a single injection of 33 ml ropivacaine for subclavian perivascular block and 5 ml to block the intercostobrachial nerve in the axilla. One group (n =8) received 0.5 per cent ropivacaine without epinephrine (190 mg) and the other (n =9) received 0.5 per cent ropivacaine with epinephrine 1:200,000 (190 mg). Plasma ropivacaine concentrations were measured from peripheral venous blood samples taken for 12 hr after drug administration. Ropivacaine base was determined in plasma using gas chromatography and a nitrogen-sensitive detector. The mean peak plasma concentration (Cmax) was 1.6 ± 0.6 mg· L−1 and 1.3 ± 0.4 mg· L−1 after administration of ropivacaine with and without epinephrine. The median time to peak plasma concentration (tmax) was 0.75 hr and 0.88 hr and the mean area under the plasma concentration curve AUC0-12h was 7.7 ± 3.6 and 7.0 ± 3.4 mg · 1 hr−1. The differences were not statistically significant. The terminal phase of the individual plasma concentrationtime curves showed a varying and sometimes slow decline possibly indicating a sustained systemic uptake of ropivacaine from the brachial plexus. No central nervous system or cardiovascular symptoms attributed to systemic plasma concentrations of the drug were observed, with the dose (1.90–3.28 mg · kg−1) of ropivacaine used. It is concluded that the addition of epinephrine does not alter the pharmacokinetic properties of ropivacaine when used for subclavian perivascular brachial plexus block.RésuméLe but de cet étude était de déterminer la pharmacocinetique de l’anesthésique local ropivacaine utilisé avec ou sans épinéphrine pour un bloc de plexus brachiale. Dixsept patients adultes ASA I ou 2 devant subir des chirurgies orthopédiques électives out reçu une injection unique de 33 ml de ropivacaine pour un bloc perivasculaire sous claviere 5 ml afin de bloquer le nerf intercostal brachial à I’aisselle. Un groupe (n =8) a reçu 0.5 pour cent de ropivacaine sans épinéphrine (190 mg) et l’autre (n =9) a reçu 0.5 pour cent de ropivacaine avec epinephrine 1:200,000 (190 mg). Les concentrations plasmatiques de ropivacaine out été mesurées à partir d’échantillons veineux périphériques 12 heures apres l’administration de la drogue. La base de ropivacaine a été déterminee dans le plasma utilisant la chromotographie et un détecteur sensible à l’azote. Les concentrations plasmatiques moyennes les plus élevées (Cmax) était de 1.6 ± 0.6 mg · L−1 et 1.3 ± 0.4 mg· L−1 après administration de ropivacaine avec ou sans épinéphrine. Le temps moyen pour atteindre la concentration plasmatique maximale (tmax) était de 0.75 heures et 0.88 heures vu la moyenne de la surface sous la courbe de concentration plasmatique AUC0–12h était de 7.7 ± 3.6 et7.0 ± 3.4 mg ·1 hr−1−1. Les differences n’ ètaient pas statistiquement significatives. La phase terminale des courbes des concentrations plasmatiquestemps out demontre un declin variable el des fois lent indiquant possiblement une rétention systemique soutenue ds ropivacaine a partir du plexus brachial. Aucun symptome cardiovasculaire ou nerveux central attribue aux concentrations plasmatiques de la drogue furent observe avec des doses de (1.90–3.28 mg · kg−1)de ropivacaine utilisée. On conclut que l’addition d’épinéphrine n’allère pas la pharmacocinetique de la ropivacaine lorsqu’utilisée pour un bloc de plexus brachial.

Brachial plexus block with a new local anaesthetic: 0.5 percent ropivacaine

A new local anaesthetic, ropivacaine hydrochloride, was used in a concentration of 0.5 per cent in 32 patients receiving a subclavian perivascular block for upper extremity surgery. One group (n = 15) received 0.5 per cent ropivacaine without epinephrine and a second group (n = 17) received 0.5 per cent ropivacaine with epinephrine in a concentration of 1:200,000. Anaesthesia was achieved in 87 per cent of the patients in both groups in all of the C5 through T1 brachial plexus dermatomes. Motor block was profound with 100 per cent of patients in both groups developing paresis at both the shoulder and hand and 100 per cent developing paralysis at the shoulder. There was a rapid initial onset of sensory block (a mean of less than four minutes for analgesia) with a prolonged duration (a mean of greater than 13hr of analgesia). The addition of epinephrine did not significantly affect the quality or onset of sensory or motor block. The duration of sensory block was reduced by epinephrine at T1 for analgesia and at C7, C8, and T1 for anaesthesia. The duration of sensory block in the remaining brachial plexus dermatomes as well as the duration of motor block was not effected by epinephrine. There was no evidence of cardiovascular or central nervous system toxicity in either group with a mean dose of 2.5– 2.6 mg · kg− 1 ropivacaine.RésuméAfin de permettre une intervention chirugicale sur le membre supérieur, nous avons fait chez 32 patients un bloc périvasculaire par approche sous- clavière en utilisant une solution de 0,5 pour cent d’hydrochlorure de ropivacaïne. Cette solution était employée seule (groupe I, n = 15) ou enrichie d’adrénaline à 1:200 000 (groupe II, n = 17). Nous avons obtenu une anesthésie de tous les dermatomes entre C5 et D1 chez 87 pour cent des patients des deux groupes. Le bloc moteur était intense avec une paralysie de l’épaule et au moins une parésie de la main chez tous les patients. Le bloc sensitif s’installait rapidement et durait longtemps (l’analgésie survenait en moins de quatre minutes et durait plus de 13 heures en moyenne). L’addition d’adrénaline n’eut en général pas d’effet sur la latence, la qualité et la durée des blocs moteurs et sensitifs sauf celui d’abréger l’analgésie dans le territoire de D1 et l’anesthésie dans celui de C7 à D1. Avec des doses moyennes de 2,5 et 2,6 mg· kg− 1 de ropivacaine, nous n’avons noté de signe de toxicité centrale ou cardiovasculaire dans aucun des deux groupes.

Incidence of venous air embolism during cesarean section is unchanged by the use of a 5 to 10 degree head-up tilt.

One hundred healthy parturients were divided at random into two demographically similar groups and were positioned for cesarean section either horizontally or flexed 5 to 10 degrees head up, with a 15 degrees lateral tilt. A Doppler ultrasound transducer was positioned over the fourth intercostal space parasternally. Initially, two patients received spinal, three general, and 95 epidural anesthesia. Two patients subsequently needed general for failed epidural anesthesia. Changes in Doppler heart tones (greater than 15 sec duration) indicative of venous air embolism (VAE) were identified 15 times in 11 patients--seven in supine and four in head-up patients (no statistically significant difference). Six awake patients (three horizontal, three head-up) developed chest tightness or pain during surgery, but only one episode correlated with VAE. No patient developed breathlessness. Moderate hypotension (greater than 10% decrease in systolic arterial pressure [SAP]) occurred in seven of 11 (63.6%) patients with, and in 26 (29.2%) of 89 patients without, VAE (P less than 0.001). More severe hypotension (SAP less than 90 mm Hg) due to bleeding occurred once. We conclude that a modest (5-10 degrees) head-up position does not influence the occurrence of VAE in patients having cesarean section. An 11% incidence of clinically insignificant VAE, although low, is still worrisome, as even small air bubbles in the circulation are potentially harmful, especially if the foramen ovale is patent. VAE during cesarean section should be anticipated and the anesthetic management planned accordingly.

Subarachnoid and epidural calcitonin in patients with pain due to metastatic cancer

Nine patients with metastatic cancer who had pain refractory to traditional treatments received a subarachnoid injection of salmon calcitonin. Eight of the nine patients reported pain relief after subarachnoid injection varying from 1 hr to 5 days. Four of the responding patients subsequently received an epidural injection of salmon calcitonin, and two of these patients reported pain relief. Although many patients experienced pain relief, nausea and vomiting appeared to be a significant side effect, occurring in seven out of nine patients.

DOES THE SYMPATHETIC BLOCK OUTLAST SENSORY BLOCK-A THERMOGRAPHIC EVALUATION

Summa~ A study to evaluate the duration of sympathetic and sensory block in the L, and L5 dermatome distributions using thermography and pinprick was conducted. Twenty patients received epidural block using 2% lidocaine with epinephrine. Onset and duration of the sensory and sympathetic blocks were determined and compared statistically. There was no difference between the duration of sensory and sympathetic block over the L2 dermatome, but sympathetic block was significantly longer than sensory block in the L, dermatome. This study demonstrates that the duration of sympathetic block can be either longer or shorter than sensory block in L, and L, dermatomes. This has important implications for interpretation of results of differential epidural studies in that one cannot predict the duration of sympathetic block based on duration of sensory block.

Subarachnoid Alcohol Block

In 1931, Dogliotti [1] first described the technique and indications for using intrathecal alcohol for the relief of intractable pain. He suggested its use as a safer and simpler alternative to the various neurosurgical measures (posterior rhizotomy, cordotomy, sympathectomy) that were available for chronic pain patients at that time. Dogliotti felt there were patients who were either too sick or whose life expectancy was too uncertain to warrant the risk of a not-always-successful surgery.

Does the sympathetic block outlast sensory block: a thermographie evaluation

&NA; A study to evaluate the duration of sympathetic and sensory block in the L2 and L5 dermatome distributions using thermography and pinprick was conducted. Twenty patients received epidural block using 2% lidocaine with epinephrine. Onset and duration of the sensory and sympathetic blocks were determined and compared statistically. There was no difference between the duration of sensory and sympathetic block over the L2 dermatome, but sympathetic block was significantly longer than sensory block in the L5 dermatome. This study demonstrates that the duration of sympathetic block can be either longer or shorter than sensory block in L2 and L5 dermatomes. This has important implications for interpretation of results of differential epidural studies in that one cannot predict the duration of sympathetic block based on duration of sensory block.