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M Stanton-Hicks

Publications and source records attributed to M Stanton-Hicks.

36 records · Page 2Linked to original sources
PubMed1995

Long-term intraspinal infusions of opioids in the treatment of neuropathic pain.

Long-term intraspinal infusions of opioid drugs are being increasingly utilized in patients with noncancer pain. Despite this, there is a lack of long-term information, including success and failure rates for pain relief and technical problems. During a 5-year period, 18 noncancer patients underwent implantation of programmable infusion pumps for long-term intrathecal opioid infusion. Patients had (a) neuropathic pain, (b) had failed or been ineligible for noninvasive treatments, and (c) obtained greater than 50% pain relief with intrathecal trial infusions of morphine sulfate or sufentanil citrate. A disinterested third-party reviewer evaluated patients at the most recent follow-up. Sixty-one percent (11/18) of patients had good or fair pain relief with mean follow-up 2.4 +/- 0.3 years (0.8-4.7 years). Average numeric pain scores decreased by 39% +/- 4.3%. Five of the 11 responders required lower opioid doses (12-24 mg/day morphine) and the remaining six patients required higher opioid doses (> 34 mg/day morphine). Failure of long-term pain relief occurred in 39% (7/18) despite good pain relief in trial infusions and the use of both morphine and sufentanil. Technical problems developed in 6/18 patients but appeared to be preventable with further experience. Long-term intrathecal opioid infusions can be effective in treatment of neuropathic pain but might require higher infusion doses.

Analgesia, Epidural↗
PubMed1991

Neuroanatomy and pathophysiology of pain related to spinal disorders.

Sensation is achieved through the integration of many neural elements: receptors, afferent and efferent neurons, the spinal cord with its subdivisions, and the higher brain centers. One of the many sensations perceived by the human body is that of pain or nociception. To understand the concept of "back pain" associated with various spinal pathologies, some basic knowledge of the anatomy and physiology of sensation, and more specifically nociception, is necessary. This knowledge is presented herein.

Back Pain↗
PubMed1991

[Postoperative analgesia following spondylodesis using a peridural catheter placed during surgery. Results of a pilot study].

For the treatment of postoperative (p.o.) pain following vertebral surgery, systemic analgesics are frequently used in high doses with a variety of side effects. It was the aim of this study to investigate p.o. epidural catheter analgesia in 20 patients following surgical correction of scoliosis using the Cotrel and Dubousset technique. METHODS. The patients received balanced general anesthesia with fentanyl and isoflurane. At the end of the operation, before closing the fascia, an epidural catheter was placed by the orthopedic surgeon. After extubation and following evaluation of the motor function of all extremities. 6-10 ml bupivacaine 0.25% was injected into the epidural catheter followed by continuous administration of 0.25% bupivacaine 4-8 ml/h. Analgesic level and hemodynamic parameters were monitored. Pain was measured by the visual analogue scale. If analgesia was not sufficient, the patients received tramadol or piritramide intravenously. RESULTS. In 11 of 20 patients epidural analgesia was rated adequate; 5 needed additional systemic analgesics, and in 4 effective analgesia was not achieved with either epidural analgesia or systemic opioids. No complications were observed. DISCUSSION. The pilot study documented that epidural analgesia using an intraoperatively placed epidural catheter can be used for p.o. pain relief after vertebral surgery using the Cotrel and Dubousset technique. Additional studies will compare the method described to other pain-relieving procedures.

Adolescent↗
PubMed1989

Arterial and mixed venous blood gas status during apnoea of intubation--proof of the Christiansen-Douglas-Haldane effect in vivo.

The Christiansen-Douglas-Haldane effect, in short the Haldane effect, describes the dependence of the CO2 binding of blood on the degree of oxygenation of haemoglobin. Under the physiological conditions of an 'open' system between blood and alveoli the partial pressure of arterial CO2 (PaCO2), must be less than that of mixed venous blood (PvCO2). During the unphysiological conditions of a 'closed' system, e.g. hyperoxic apnoea, i.e. continuous oxygen uptake without CO2 delivery by the lungs, the PaCO2 will not only approximate the PvCO2 but will even exceed it. Without the Haldane effect, rapid adjustment of PaCO2 to PvCO2 would be expected during apnoea due to the lack of CO2 excretion. If, however, as undertaken in this study, ongoing oxygenation (high alveolar PO2 (PACO2) with concomitant lack of CO2 delivery (apnoea, i.e. the CO2 concentration remains constant) lead to a continuing sufficient oxygenation of blood during its passage through the lung capillaries, then this leads to a rightwards shift of the CO2 binding curve--the Haldane effect. The resulting increase in PCO2 as shown here actually leads to an arterial-mixed venous CO2 partial pressure difference (avDPCO2) of 2.8 +/- 1.8 mmHg. The results described substantiate for the first time the existence of the Haldane effect under clinical conditions.

Apnea↗
PubMed1989

[The effect of the injection speed on the blockade characteristics of hyperbaric bupivacaine and tetracaine in spinal anesthesia].

A lack of uniform methodology used in the assessment of different injection speeds in spinal anesthesia by different authors formed the basis of the current study, which compared under randomized conditions the effects of various injection speeds during intrathecal administration of 4 ml 0.5% hyperbaric bupivacaine or 0.5% hyperbaric tetracaine. MATERIALS AND METHODS. Eighty male ASA Physical Status II and III patients scheduled for transurethral resection of the prostate under spinal anesthesia were selected. They were randomly divided into four groups of 20 each. Patients were given 4 ml of either 0.5% hyperbaric bupivacaine or 0.5% hyperbaric tetracaine according to the following scheme: I: 4 ml tetracaine/0.25 ml.s-1; II: 4 ml tetracaine/0.5 ml.s-1: III: 4 ml bupivacaine/0.25 ml.s-1; IV: 4 ml bupivacaine/0.5 ml.s-1. The study was carried out in a double-blind fashion and puncture was performed at the L3-4 interspace using a 25-gauge needle with the patient in the sitting position. Following injection of the anesthetic solution (0.25 ml.s-1 or 0.5 ml.s-1 without barbotage), the patient was immediately placed in the lithotomy position with the table remaining horizontal. The level of anesthesia using pin prick and the degree of motor blockade, using a 0 to 3+ scale where 0 represented no motor weakness and 3+ complete motor block, were assessed at specific intervals. Statistical analysis was performed using the Mann-Whitney rank sum test: P value of less than 0.05 was considered statistically significant. RESULTS. Bupivacaine injected at 0.25 ml.s-1 was associated with a higher dermatome level than at 0.5 ml.s-1 (P less than 0.05). Time to highest dermatome, however, was shorter with bupivacaine 0.5 ml.s-1 compared to 0.25 ml.s-1 (P less than 0.05) (Table 3, Fig. 1). Time to highest level of analgesia was shorter with tetracaine 0.25 ml.s-1 compared to 0.5 ml.s-1 (P less than 0.05) (Fig. 2). At 0.25 ml.s-1, tetracaine achieved the highest dermatome faster than bupivacaine (P less than 0.05). Tetracaine injected at 0.5 ml.s-1, however, was associated with a higher segmental level than bupivacaine (P less than 0.05). At 0.25 ml.s-1 bupivacaine and tetracaine achieved a 3+ motor block faster than at 0.5 ml.s-1 (P less than 0.05). Complete motor blockade, however, was significantly longer with tetracaine at both injection speeds (0.25 and 0.5 ml.s-1) compared to bupivacaine (P less than 0.05). CONCLUSIONS. The results suggest that 4 ml 0.5% hyperbaric bupivacaine or tetracaine injected at 0.25 or 0.5 ml.s-1 provides a rapid and reproducible spread of analgesia for transurethral surgery. However, our findings suggest that speed of injection is of little i

Aged↗
PubMed1987

Venoconstrictor agents mobilize blood from different sources and increase intrathoracic filling during epidural anesthesia in supine humans.

The authors studied the effects of dihydroergotamine (DHE) and etilefrine hydrochloride (E) on the regional distribution of 99mTc-marked erythrocytes during epidural anesthesia in eight supine men to determine if vasoactive agents with venoconstrictor action would enhance cardiac filling during epidural anesthesia. Radioactivity was recorded with a gamma camera, and its distribution determined in the thorax, abdomen, and limbs. Arterial and central venous pressure, heart rate, and calf volume by plethysmography were measured. During epidural anesthesia with a sensory block up to T4/5, DHE (7.5 micrograms/kg) reduced the radioactivity, i.e., blood volume, in both the innervated (-5.9 +/- 3.5%) and denervated muscle/skin (-16.9 +/- 7%) regions, and increased it in both the intrathoracic (+7.0 +/- 2.3%), and splanchnic vasculature (+4.2 +/- 3.2). In contrast, E (6 micrograms X kg-1 X min-1) decreased the blood volume most markedly in the splanchnic region (-5.4 +/- 0.7%) and increased it in the thorax (+2 +/- 0.6%). All these changes were statistically significant. The combined effects were estimated to be equivalent to a transfusion of nearly 1.01 of blood. Both drugs reversed the hypotensive action of epidural anesthesia. During epidural anesthesia, DHE preferentially constricted the capacitance vessels in skeletal muscle and skin irrespective of the state of innervation, whereas E preferentially constricted the splanchnic vasculature. In the doses used, the two agents replenished in an additive fashion the central circulation during epidural anesthesia.

Adult↗
PubMed1987

[Effect of dihydroergotamine (DHE) on blood volume and circulation in the calf in peridural anesthesia in the human].

Dihydroergotamine (DHE) preferentially constricts capacitance vessels in the skin and striated musculature, thereby redistributing blood in favor of the pulmonary vascular bed in the presence of neurogenic vascular tone. The aim of this study was to see if DHE would act likewise when neurogenic vascular tone is absent. Filling and blood flow of the calves were measured plethysmographically in six healthy, supine male volunteers before and during peridural anesthesia (PDA) to the level of at least T5 and, in the denervated state, after the injection of DHE 7.5 micrograms/kg intravenously. Arterial blood pressure, central venous pressure (CVP), and heart rate were also determined. Both blood flow (+2.2 ml/min per 100 ml tissue) and volume (+1 ml/100 ml tissue) of the calves increased while CVP and systolic arterial pressure decreased during PDA (Table 1). DHE did not affect the PDA-included increase in blood flow, but strongly reduced calf volume (-1.7 ml/100 ml tissue). This was accompanied by an increase in CVP and systolic blood pressure (Fig. 1). In the absence much as in the presence of neurogenic vascular tone, DHE preferentially constricts capacitance but not resistance vessels. Thus, DHE counteracts the vascular effects of PDA, as it improves cardiac filling and consequently raises arterial blood pressure by redistributing blood from the dilated capacitance vessels without curtailing blood flow. It would appear, therefore, that DHE is a rational alternative to fluid therapy for the prophylaxis of arterial hypotension during major conduction anesthesia.

Adult↗
PubMed1985

Peridural anesthesia and the distribution of blood in supine humans.

To determine the effects of vasomotor tone on intrathoracic and splanchnic blood volume, the distribution of radioactively (99mTc) labeled erythrocytes was recorded by whole body scintigraphy before and during peridural anesthesia (PDA) in eight supine men. The radioactivity was recorded with a gamma camera and its distribution determined in the thorax, abdomen, and limbs. Arterial and central venous pressure, heart rate, and calf volume and flow also were measured. During PDA with a sensory block up to T4/5, radioactivity increased only in the denervated legs (+ 9.9 +/- 2.3% SE), whereas it decreased in all other regions, i.e., in the thorax (-8.1 +/- 1.2%), the innervated upper limbs (-10.6 +/- 4.0%), and in the splanchnic vasculature (-5 +/- 1.7%). However, in two of the subjects, after an initial decrease, splanchnic blood content increased while intrathoracic blood volume decreased further. The effects of PDA on thoracic and splanchnic filling could be duplicated by the sequestration of about 500-600 ml of blood in both legs. In supine humans high peridural anesthesia evokes the same decrease in intrathoracic blood volume as orthostasis. This seems to be counteracted by a reflex decrease in filling of the denervated muscle and skin areas and also by a constriction of the splanchnic vasculature by an unknown mechanism. Potential circulatory collapse may ensue when the vasoconstrictor response fails in the splanchnic circulation.

Adult↗
PubMed1976

Effects of extradural block: comparison of the properties, circulatory effects and pharmacokinetics of etidocaine and bupivacaine.

Five healthy, unmedicated male volunteers, aged 19-25 yr, participated in a double-blind, crossover study. Each subject received, on separate occasions and via a catheter placed at L2, 1.5% etiodocaine HCl20 ml with adrenaline 5 mug/ml, or 0.75% bupivacaine HCl 20 ml with adrenaline 5 mug/ml for extradural analgesia. In addition, in order to calculate the absorption rate of the local anaesthetic agent, each subject received on two further occasions etidocaine HCl 75 mg and bupivacaine HCl 75 mg respectively by i.v. infusion, over a period of 10 min. Spread of sensory analgesia to four segments above and below the site of injection was faster with etidocaine (13 +/- 3 min) (mean +/- SD) than with bupivacaine (22 +/- 8 min). Two-segment regression occurred later for bupivacaine (260 +/- 57 min) than for etidocaine (180 +/- 96 min). Caudal spread of analgesia was more extensive with etidocaine than with bupivacaine. The onset of motor blockade tended to be faster with etidocaine (5.8 +/- 3.0 min), than with bupivacaine (10.0 +/- 3.5 min); regression of motor blockade by one unit was longer with etidocaine (306 +/- 103 min) than bupivacaine (238 +/- 75 min). Sudomotor block occurred earlier with etidocaine (4.0 +/- 2.1 min) than bupivacaine (13.7 +/- 4.8 min). Significant changes in cardiac stroke work and stroke volume occurred. For etidocaine these measurements remained below control values for 120-210 min after injection. The mean maximum arterial plasma concentration of etidocaine was 1.52 +/- 0.64 mug/ml, at 14 +/- 2 min and of bupivacaine was 1.35 +/- 0.63 mug/ml, achieved at 20 +/- 4 min. The systemic absorption of both drugs occurred in a biphasic pattern with a fast and slow half-life of 0.3 and approximately 8 h respectively.

Acetanilides↗
PubMed1976

The effects of adding adrenaline to etidocaine and lignocaine in extradural anaesthesia I: block characteristics and cardiovascular effects.

The addition of adrenaline 5 mug/ml, 1 : 200 000 to 1% etidocaine hydrochloride administered extradurally (L2-3) shortened significantly the onset time for sensory blockade, particularly with respect to the spread of the analgesia from the injection site, and shortened the already rapid onset of motor block. Etidocaine hydrochloride 1% plain caused a slower onset of block, laster longer and produced more profound analgesia over the caudal dermatomes than did 2% lignocaine hydrochloride. The motor block from plain etidocaine was more profound in its extent and lasted longer than that caused by lignocaine. With regard to cardiovascular variables, there were no significant differences between subjects receiving the plain etidocaine and the plain lignocaine. However, subjects receiving etidocaine with adrenaline exhibited increased cardiac stimulation and a decrease in total peripheral resistance over the first 150 min.

Acetanilides↗
PubMed1976

Hemodynamic drug interaction: peridural lidocaine and intravenous ephedrine.

Hypotension following peridural anesthesia with lidocaine was treated by intravenous injection of ephedrine. The ephedrine relieved the cardiovascular depression, but was associated with a concomitant increase in plasma lidocaine concentrations. This increase may push the plasma lidocaine concentration into the toxic region.

Adult↗
PubMed1975

Effects of peridural block: V. Properties, circulatory effects, and blood levels of etidocaine and lidocaine.

Ten healthy, unpremedicated, male volunteers, aged 21-33 years, were given 20 ml 1 per cent etidocaine with 5 mug/ml epinephrine for peridural analgesia via a catheter placed L2. On a different occasion they were given 20 ml 2 per cent lidocaine with 5 mug/ml epinephrine in the same manner. Initial onset of sensory analgesia to pin prick was faster for etidocaine (7 min) than for lidocaine (9 min). Analgesia lasted significantly longer after etidocaine with respect to both two-segment regression (177 plus or minus SE min vs. 114 plus or minus 8 min) and total duration (379 plus or minus 22 min vs. 190 plus or minus 8 min). Onset of maximal motor blockade was significantly faster with etidocaine (15.4 plus or minus 2.5 min) than with lidocaine (31.7 plus or minus 3.3 min); blockade lasted longer with etidocaine (331 plus or minus 25 min vs. 167 plus or minus 13 min). Changes in mean arterial pressure cardiac output, central venous pressure, limb blood flows, total peripheral resistance, and stroke volume were similar with the two drugs, although those after etidocaine were more prolonged as a result of the longer blockade. Mean maximum arterial concentrations of etidocaine were 0.96 plus or minus 0.05 SE mug/ml (plasma) and 0.55 plus or minus 0.03 mug/ml (whold blood), achieved at 17 plus or minus 2 min. Mean maximum arterial concentrations of lidocaine were 2.22 plus or minus 0.09 mug/ml (plasma) and 1.85 plus or minus mug/ml (whold blood), achieved at 24 plus or minus 2 min. No sign of central toxicity was observed with either drug, although subjects receiving lidocaine tended to sleep, which was not the case with etidocaine. Hematologic screening, blood chemistries, and urinalyses performed 24 hours before and after each study showed no abnormality.

Acetanilides↗
PubMedDate not supplied

Pain outcomes after intestinal surgery.

Pain sensation and distress in 38 intestinal surgical patients were moderate to severe on postoperative day 1, ranging from 34 to 49 mm and 33 to 45 mm, respectively, on 100-mm scales. During ambulation, both increased from baseline to post-ambulation, P < 0.01. Half of the patients reported severe pain not relieved by analgesics, and although 44% learned a relaxation technique in the past, only 8% used one for pain after this surgery. Pain disturbed the sleep of 34% of the patients, and pain was related to respiratory, intestinal, febrile, and other complications in 18 (47%) subjects. Attentive analgesic use and nonpharmacologic therapies are recommended.

Adult↗
PubMedDate not supplied

Exogenous and endogenous plasma levels of epinephrine during dental treatment under local anesthesia.

BACKGROUND AND OBJECTIVES: To determine serum levels of catecholamines after local anesthesia for dental treatment, we used tritium-labeled epinephrine as a vasoconstrictor for dental local anesthesia. METHODS: Twenty healthy male outpatients undergoing standardized dental treatment (deep scaling) were studied. In all patients, only one quadrant was anesthetized even though the treatment was performed on all teeth. Two milliliters of articaine 4% (amide anesthetic) with 20 micrograms epinephrine was used as local anesthetic. Of the total epinephrine administered, 1.2% (100 microCi) consisted of tritium-labeled epinephrine. Blood samples were drawn through a central venous catheter before and at frequent intervals after the local anesthetic solution was administered. RESULTS: A dramatic increase in exogenous epinephrine was observed in four patients during injection (up to 6937 pg/mL). The other 16 patients demonstrated a continuous increase in applied epinephrine that peaked on average at the 7th minute (631.5 +/- 41.4 pg/mL). A second increase occurred after the beginning of the dental procedure. The mean total epinephrine levels were always higher than those of the applied epinephrine. Extrasystoles were observed in two of four and tachycardia in three of four patients with high plasma levels of applied epinephrine. Increases in total epinephrine were associated with exogenous catecholamine administration, whereas the dental treatment did not significantly influence the plasma levels. CONCLUSION: Despite aspiration in 20% of the patients, an unintended intravascular injection occurred. Although healthy young men tolerated large increases in central plasma epinephrine levels surprisingly well, this may not be the case in patients with concurrent cardiovascular disease. Patients at cardiovascular risk should be under continuous monitoring when an epinephrine-containing solution is applied.

Adult↗