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PubMed1994

Effect of neuromuscular blockade on facial nerve monitoring.

Direct facial nerve stimulation and monitoring during cerebellopontine angle (CPA) tumor surgery are critical for identification and preservation of function. Electrically evoked facial nerve monitoring was compared with ulnar train-of-four monitoring under progressive neuromuscular blockade. Using a rabbit model, the facial nerve function of six controls was compared to that of six specimens with acute or chronic injuries. Eight of 18 patients who had undergone CPA tumor resection during one year were also studied. Regression analysis correlated between ulnar nerve monitoring and facial electromyographic (EMG) peak voltage in all groups. Facial EMG was measurable, even with 75 percent receptor blockade. The results of this study support the hypothesis that high degrees of neuromuscular blockade do not preclude satisfactory EMG monitoring of the facial nerve during CPA tumor surgery. This study did demonstrate that chronically injured facial nerves may show greater sensitivity to the effects of neuromuscular blockade. Lower levels or avoidance of neuromuscular blockade should be employed under these circumstances.

Animals↗

PubMed1996

Myogenic motor-evoked potential monitoring using partial neuromuscular blockade in surgery of the spine.

STUDY DESIGN: The authors analyzed motor-evoked potentials using transcranial electrical cortical stimulation during spinal surgery in 40 patients under conditions of partial neuromuscular blockade. OBJECTIVES: The results were used to investigate the utility of motor-evoked potential monitoring to prevent neurologic injury in spinal surgery. SUMMARY OF BACKGROUND DATA: Noninvasive transcranial electrical motor-evoked potentials are reportedly effective in predicting postoperative spinal cord deficits caused by intraoperative occurrences. However, the sensitivity and specificity of these predictions have not been assessed under conditions of partial neuromuscular blockade during a wide variety of surgical procedures. METHODS: Compound muscle action potentials were recorded at the tibialis anterior muscle while general anesthesia was maintained with nitrous oxide, etomidate, and sufentanil. Surgery was performed at all spinal levels for a variety of diagnoses. RESULTS: Reference motor-evoked potential amplitudes, measured after induction of partial neuromuscular blockade, ranged from 25 to 7562 microV (median, 600 microV). Variation in intraoperative motor-evoked potential amplitude ranged from signal loss to a 3440% increase. A decrease to less than 20% of the individual reference value for motor-evoked potential amplitude occurred at least once in nine patients (22.5%) but as not associated with postoperative motor deficits. Two patients who had loss of motor-evoked potential signal without recovery did have postoperative motor deficits. Motor-evoked potentials predicted postoperative motor improvement in six patients. An improvement threshold of 160% of the reference amplitude predicted postoperative motor improvement with 100% sensitivity and 81% specificity. CONCLUSIONS: The authors support the utility of recording transcranial electrical motor-evoked potentials in spinal surgery under partial neuromuscular blockade. Recovery of lost motor-evoked potentials was not associated with postoperative motor deficits, whereas non-recovery of lost motor-evoked potentials was.

Adolescent↗

PubMed1992

[Vecuronium-induced neuromuscular blockade in two patients with hyperparathyroidism and a patient with hypoparathyroidism].

Vecuronium-induced neuromuscular blockade was evaluated in two patients with primary hyperparathyroidism and in a patient with hypoparathyroidism. A 39 year old male with typical primary hyperparathyroidism was scheduled for surgical removal of the parathyroid adenoma. Serum levels of calcium and ionized calcium were 15.0 mg.dl-1 and 1.95 mmol.l-1, respectively. A 44 year old female suffering from primary hyperparathyroidism was also scheduled for surgical removal of the adenoma. Serum levels of calcium and ionized calcium were 12.5 mg.dl-1 and 1.51 mmol.l-1, respectively. A 63 year old male, suffering from postoperative secondary hypoparathyroidism and treated with calcium, was scheduled for surgical removal of the recurrent pharyngeal cancer. Serum levels of calcium and ionized calcium were 9.0 mg.dl-1 and 1.15 mmol.l-1, respectively. Anesthesia was induced with thiamylal 4-5 mg.kg-1 and vecuronium 0.08 mg.kg-1 and was maintained with 70% nitrous oxide in oxygen and fentanyl in all three patients. Neuromuscular blockade following the administration of vecuronium was measured by a big toe abduction evoked by supramaximal stimulation of the tibial nerve (Myograph 2000, Biometer, Denmark). In order to evaluate the effect of serum calcium level on vecuronium neuromuscular blockade, ten patients with normal serum levels of calcium, were examined in the same fashion. In only one patient with hyperparathyroidism, whose serum calcium was 15.0 mg.dl-1, the onset and the duration of vecuronium were later and shorter than those of other patients with normal serum levels of calcium. In conclusion, we should pay attention to the antagonistic responses to vecuronium in patients with severely high levels of serum calcium.

Adult↗

PubMed1985

Resistance to metocurine-induced neuromuscular blockade in patients receiving phenytoin.

Recent reports have described resistance to pancuronium-induced neuromuscular blockade in patients chronically receiving anticonvulsants. This study examines the pharmacokinetics and pharmacodynamics of metocurine (MTC) in 12 patients undergoing craniotomy--six on chronic phenytoin therapy and six comparable controls. Each patient received MTC 0.2 mg/kg during the induction of general anesthesia. Quantification of plasma MTC concentration was performed by radioimmunoassay, while the response to MTC was evaluated by evoked compound electromyography (ECEMG). Patients in the phenytoin group were resistant to this dosage of MTC, as demonstrated by their response (83 +/- 16% compared with 98 +/- 2% depression of ECEMG in control patients, P less than 0.05) and by recovery index, defined as the time required for recovery from 25 to 75% of the control ECEMG (53 +/- 22 min compared with 125 +/- 54 min in control patients, P less than 0.01). Similarly, the total duration of neuromuscular blockade, measured to recovery to 90% of control ECEMG, was significantly shorter in the phenytoin group (122 +/- 25 min compared with 269 +/- 64 min in the control group, P less than 0.01). Plasma concentration-time curves were fit to biexponential equations for both groups. These were used to generate two-compartment models. Neither the model parameters nor the plasma concentrations of MTC at any time in the study were significantly different for the two groups. The pharmacodynamic analysis, however, showed that patients on phenytoin require a higher plasma concentration of MTC (0.415 +/- 0.095 microgram/ml compared with 0.249 +/- 0.066 microgram/ml in control patients at 50% ECEMG, P less than 0.01) to effect a given level of neuromuscular blockade.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

Enzymatic antagonism of mivacurium-induced neuromuscular blockade by human plasma cholinesterase.

BACKGROUND: Mivacurium chloride is a bis-benzylisoquinolinium nondepolarizing neuromuscular blocking agent, hydrolyzed by butyrylcholinesterase (PCHE). The dose-response relationships for PCHE after mivacurium have not been studied. Therefore, this study was designed to establish dose-response relationships for PCHE as an antagonist of mivacurium-induced neuromuscular blockade. METHODS: Forty-eight physical status 1 adults were given 0.15 mg/kg mivacurium during fentanyl-thiopental-nitrous oxide-isoflurane anesthesia. Train-of-four (TOF) stimulation was applied to the ulnar nerve every 12 s, and the force of contraction of the adductor pollicis muscle was recorded. When spontaneous recovery of first twitch height (T1) reached 10% of its initial control value, exogenous PCHE equivalent to activity present in 2.5, 5, 7.5, 15, or 25 ml/kg of human plasma was administered by random allocation to 40 patients. Neuromuscular function in another eight subjects was allowed to recover spontaneously. Two blood samples were taken for determination of plasma cholinesterase activity. The first sample was taken before induction of anesthesia, and the second sample was taken when the TOF ratio had recovered to 0.75. Dibucaine and fluoride numbers were determined from the first assay. RESULTS: Administration of PCHE produced significant increases in PCHE activity in all patients. The larger the dose, the greater was the resultant plasma activity. Human PCHE produced a dose-dependent antagonism of mivacurium-induced neuromuscular blockade and the recovery times correlated inversely with PCHE activity (P < 0.01). The recovery of T1 was greater (P < 0.01) and time to attain a TOF ratio of 0.75 was shorter (P < 0.01) with any dose of PCHE than that observed in the spontaneous recovery group. After the administration of exogenous PCHE equivalent to activity present in 25 ml/kg of human plasma, recovery of TOF ratio to 0.75 or more was observed in all patients in less than 10 min and time to attain a TOF ratio of 0.75 was 55% shorter than the spontaneous recovery group (8.4 [7.1-9.7] vs. 18.7 [15.4-22] min; mean and 95% confidence intervals). CONCLUSIONS: Administration of exogenous PCHE equivalent to activity present in 25 ml/kg of human plasma (in a 65-kg patient, this dose is equivalent to PCHE activity of 1,625 ml of adult human plasma) resulted in reliable antagonism of mivacurium-induced neuromuscular blockade. Nevertheless, because of the prohibitive cost of this compound, this reversal modality is unlikely to have a routine practical application at this time.

Adolescent↗

PubMed2003

Sedation and neuromuscular blockade in paediatric intensive care: a review of current practice in the UK.

BACKGROUND: Our aim was to investigate the current practice of sedation and neuromuscular blockade in critically ill children in paediatric intensive care units (PICUs) in the UK. METHODS: A postal questionnaire was sent to all PICUs in the UK. RESULTS: The most commonly used sedative agents were midazolam in combination with morphine. Written clinical guidelines for the sedation of critically ill children were available in 45% of units. Sedation is formally assessed in 40% of units. Vecuronium is the most commonly used neuromuscular blocking agent. In the UK, 31% of critically ill children are likely to receive neuromuscular blocking agents. Depth of neuromuscular blockade is routinely assessed in 16% of patients. CONCLUSIONS: Relatively few units possess clinical guidelines for the sedation of critically ill children, and only a minority formally assess sedation levels. Where neuromuscular blocking agents are administered, sedation is frequently inadequately assessed and the depth of neuromuscular blockade is rarely estimated.

Child↗

PubMed2004

Hipocrates: a robust system for the control of neuromuscular blockade.

OBJECTIVE: Development of an automatic system (software package Hipocrates) for the control of neuromuscular blockade by continuous infusion of the non-depolarising types of muscle relaxant drugs presently used in anaesthesia, namely atracurium, cisatracurium, vecuronium and rocuronium. METHODS: Hipocrates incorporates control strategies based upon classical, adaptive and robust control, as well as a wide range of noise reduction techniques and on-line adaptation to patient-specific characteristics. Therefore, the system provides strong robustness to inter- and intra-individual variability of the patients responses or unexpected circumstances and adaptation to the individual requirements. RESULTS: The control system is easy to set up and to use in a clinical environment. It consists of a portable PC computer, a Datex AS/3 NMT sensor and a B/Braun compact perfusion pump. In the simulation mode the software package incorporates sophisticated generation of pharmacokinetic/pharmacodynamic models driven by simulated drug administration regimes (bolus, continuous infusion and a combination of both). CONCLUSIONS: Hipocrates is an advanced standalone application for the control of neuromuscular blockade with a friendly graphic interface. It has been extensively validated, and it can be used on patients undergoing surgery as well as for simulation studies. Therefore Hipocrates also provides an excellent environment for education and training purposes.

Anesthesia, General↗

PubMed1976

Antagonism of neuromuscular blockade.

Although acetylcholinesterase inhibitors are accepted antagonists of nondepolarizing neuromuscular blockade, many basic questions are still unanswered. What is the relationship between receptor occupancy and adequate ventilation? What are the effects of changes in acid-base balance and temperature? What are the mechanisms of the various antibiotic-induced neuromuscular blockades, and what antagonizes them? This review is an attempt to summarize the known factors infuencing relaxant blocks and to identify the unknown factors. The need for further studies is obvious.

Acid-Base Equilibrium↗

PubMed1994

Onset of action of mivacurium chloride. A comparison of neuromuscular blockade monitoring at the adductor pollicis and the orbicularis oculi.

BACKGROUND: The optimal site for monitoring neuromuscular blockade for intubations facilitated with mivacurium chloride has not been established. The primary purpose of this evaluation was to determine the difference in onset of neuromuscular blockade between the orbicularis oculi and adductor pollicis in patients administered mivacurium chloride. We also evaluated intubating conditions when intubation was timed to maximal neuromuscular blockade at either the orbicularis oculi or the adductor pollicis. The results for patients administered mivacurium chloride were compared with those for a control group administered succinylcholine. METHODS: In a double-blind randomized design, the time to loss of the compound muscle action potential at the orbicularis oculi and adductor pollicis was monitored in 20 patients administered mivacurium chloride and ten patients administered succinylcholine. After administration of mivacurium chloride (0.15 mg.kg-1), ten patients underwent tracheal intubation at maximal depression of the orbicularis oculi (group 2) and ten patients at maximal depression of the adductor pollicis (group 3). In an additional ten patients the trachea was intubated 60 s after administration of succinylcholine (1 mg.kg-1) (group 1, control). Intubation and evaluation of conditions was performed by one investigator blinded to patient treatments. RESULTS: Loss of compound muscle action potential at the orbicularis oculi and adductor pollicis was more rapid in group 1, and intubation was completed at 86 +/- 26 s. In the patients administered mivacurium chloride, the orbicularis oculi compound muscle action potential was lost 3 min earlier than the adductor pollicis compound muscle action potential. Subsequently, intubation was completed at 134 +/- 50 s in the orbicularis oculi group, whereas the time to intubation was 321 +/- 57 s in the adductor pollicis group. There was no significant differences in intubation conditions between the mivacurium chloride groups. CONCLUSIONS: When monitoring 95% twitch height depression of the orbicularis oculi muscle, intubation can be accomplished in approximately 2 min after administration of mivacurium chloride (0.15 mg.kg-1). Because intubating conditions were comparable to the patients administered succinylcholine or intubated during monitoring of the twitch height depression of the adductor pollicis, we believe that optimal site for monitoring during intubation using mivacurium chloride is the orbicularis oculi muscle.

Action Potentials↗

PubMed1996

Intraoperative electrophysiologic monitoring of ocular motor nerves under conditions of partial neuromuscular blockade during skull base surgery.

The feasibility and usefulness of intraoperative electromyographic monitoring of the oculomotor nerve (CN III), trochlear nerve (CN IV), and abducens nerve (CN IV) were evaluated under conditions of partial neuromuscular blockade in 21 patients undergoing skill base surgery. Intracranial electrical stimulation of each nerve was performed, and compound muscle action potentials (CMAPs) were reconded from the inferior or superior rectus muscle, the superior oblique muscle, and the lateral rectus muscle for monitoring of CN III, IV, and VI, respectively. Partial neuromuscular blockade was achieved by controlled infusion of vecuronium titrated to eliminate about 90% of the twitch response of the abductor pollicis brevis to electrical stimulation of the median nerve. A total of 30 cranial nerves were stimulated intraoperatively. Of these, 29 were successfully monitored (19 CN III, 6 CN IV, 4 CN VI). A relationship was found between intraoperative findings of cranial nerve monitoring, such as disappearance of response and increase in latency and stimulus threshold during manipulation of a lesion, and the presence of postoperative nerve deficits. We conclude that intraoperative electromyographic monitoring of ocular motor nerves is feasible during partial neuromuscular blockade, and that partial neuromuscular blockade does not affect the relationship between findings of intraoperative monitoring and postoperative nerve function.

Journal Article↗

PubMed2005

Gabexate mesilate hastens recovery from vecuronium-induced neuromuscular blockade.

BACKGROUND AND OBJECTIVE: To test the hypothesis that gabexate mesilate, a protease inihibitor, hastens recovery from neuromuscular blockade, we examined the effect of gabexate mesilate on the recovery of vecuronium-induced neuromuscular blockade in anaesthetized patients in a double-blind, randomized fashion. METHODS: Thirty adult patients were divided into two groups of 15. In the gabexate mesilate group, immediately after administration of vecuronium 0.1 mg kg(-1), a continuous infusion of gabexate mesilate was started at a speed of 1.5 mg kg(-1) h(-1). In the control group, normal saline was administered instead of gabexate mesilate. Times to the return of T1, T2, T3 or T4 (first, second, third and fourth response of train-of-four (TOF)), times to the recovery of T1/control to 0.25 (T25) or 0.5 (T50), recovery of T1/control or TOF ratio (T4/T1) were compared between the two groups. RESULTS: Times to the returns of T1, T2, T3 and T4 in the gabexate mesilate group were significantly shorter than in the control group (19.4 +/- 6.8 vs. 25.7 +/- 7.2 min for T1; mean +/- SD, P = 0.020). Times to T25 and T50 were significantly shorter in the gabexate mesilate group than in the control group (34.0 +/- 9.9 vs. 51.3 +/- 10.2 min for T25, P < 0.001). T1/control and TOF ratio in the gabexate mesilate group were significantly higher than in the control group 40-80 min and 40-120 min after administration of vecuronium, respectively (P < 0.05). CONCLUSION: Gabexate mesilate hastens recovery from neuromuscular block in anaesthetized patients receiving vecuronium.

Adult↗

PubMed1989

Comparison of the effects of calcium and the calcium channel stimulant Bay k 8644 on neomycin-induced neuromuscular blockade.

The effects of calcium and the calcium channel stimulant Bay k 8644 on neomycin-induced neuromuscular blockade were evaluated using rat phrenic nerve-hemidiaphragm preparations in vitro. neomycin showed maximum potency in inducing neuromuscular blockade when the calcium concentration in the bath was 1 mM. Higher calcium concentrations (1.5, 2 and 4 mM) produced a gradual decrease in neomycin potency, manifested as a progressive shift to the right of neomycin concentration-response curves. Bay k 8644 (0.1 and 1 microM) did not significantly modify indirectly elicited diaphragm contractions per se, nor did it antagonize neomycin-induced neuromuscular blockade. A higher concentration of Bay k 8644 (10 microM) antagonized indirectly elicited contractions. In conclusion, our results show that Bay k 8644, at concentrations causing calcium channel stimulation at the cardiac and vascular level, did not exert stimulant effects in a nerve-skeletal muscle preparation, suggesting that its action may be tissue-selective to a certain degree.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

PubMed1994

Localized hypothermia influences assessment of recovery from vecuronium neuromuscular blockade.

The purpose of this study was to determine the extent to which localized hypothermia of a monitored extremity alters the assessment of recovery from vecuronium-induced neuromuscular blockade. Bilateral integrated evoked electromyographic (IEMG) responses were measured in the ulner distribution of 14 anaesthetized patients who had differing upper extremity temperatures as measured at the adductor pollicis to determine whether localized hypothermia alters the clinical assessment of spontaneous recovery from vecuronium-induced neuromuscular blockade. All patients received general anaesthesia with thiopentone, N2O/O2 and opioid; 11/14 patients received isoflurane for blood pressure control. Bilateral adductor pollicis, oesophageal and ambient temperatures, and IEMG evoked response (t1) expressed as percent unparalyzed control were recorded during the anaesthetic. The difference in evoked response between the warmer and the colder upper extremity was calculated at 25%, 50% and 75% spontaneous recovery from neuromuscular blockade in the warm extremity. Differences in temperature between extremities ranged from 0.2-11 degrees C. The difference in IEMG-evoked response between extremities was proportional to the difference in temperature, and there was a direct correlation (r = 0.78) between IEMG response and extremity temperature; IEMG response was absent when extremity temperature was less than 25 degrees C. We concluded that localized hypothermia in the monitored extremity decreases the IEMG-evoked response to vecuronium neuromuscular blockade; the greater the temperature decrease, the less the evoked response.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1989

Onset and duration of neuromuscular blockade following high-dose vecuronium administration.

To determine the onset time and duration of high doses of vecuronium, 40 ASA Physical Status 1 and 2 patients were randomly assigned to receive either 100, 200, 300, or 400 micrograms/kg of vecuronium bromide for muscle relaxation during elective general surgery. Neuromuscular blockade was continuously quantitated by recording the electromyographic response to stimulation of the ulnar nerve train-of-four. The rate of onset of neuromuscular blockade, endotracheal intubating conditions, duration of neuromuscular blockade, and hemodynamic effects of vecuronium at each dose were evaluated and compared. The time from vecuronium administration to complete abolition of twitch tension (T1 = 0%) decreased from 208 +/- 41 to 106 +/- 35 s as the vecuronium dose was increased from 100 to 400 micrograms/kg (P less than 0.01). Corresponding times to endotracheal intubation (T1 less than 20%) also decreased from 183 +/- 24 to 96 +/- 31 s with increasing doses (P less than 0.01). Recovery time (T1 = 25%) increased from 37 +/- 13 to 138 +/- 24 min with increasing doses (P less than 0.01). No significant hemodynamic differences between the four groups were observed. Endotracheal intubating conditions were good or excellent in all patients. High doses of vecuronium may, therefore, be a useful alternative to succinylcholine when a rapid onset of neuromuscular blockade is required.

Anesthesia, General↗

PubMed2004

Assessing residual neuromuscular blockade using acceleromyography can be deceptive in postoperative awake patients.

UNLABELLED: Postoperative awake patients may have significant residual neuromuscular block. In awake patients, the results of accelerometry are affected by extra movements to which the thumb may be subject. In this study, we evaluated the repeatability of train-of-four (TOF) ratio using acceleromyography in 253 patients recovering from anesthesia. Immediately after arrival in the postanesthesia care unit, the ulnar nerve was stimulated with TOF stimulation. The evoked response at the thumb was measured by the TOF-Watch apparatus. The current intensity was 30 mA. Two TOF stimulations were applied and recorded at 30-s intervals. A Bland-Altman test was used. The Kappa (kappa) test for clinical agreement between the two measurements was also calculated according to the presence or absence of a residual neuromuscular blockade, defined as a TOF ratio <0.9. According to the presence of a residual neuromuscular blockade, the paired TOF ratios were discordant in 61 patients (24%; 95% confidence interval, 21%-27%). The kappa test indicated a moderate agreement (k = 0.47). We demonstrated that accelerometry as used in this study is not always accurate. Two isolated acceleromyograph TOF ratios are not an accurate representation of the neuromuscular status of the patient recovering from anesthesia. IMPLICATIONS: Clinicians should be aware that acceleromyography as used in this study does not always provide precise train-of-four ratio measurements. Two isolated acceleromyograph train-of-four ratios are not an accurate representation of the neuromuscular status of the patient recovering from anesthesia.

Adult↗

PubMed2004

Different F-wave recovery after neuromuscular blockade with pancuronium and mivacurium.

We performed this study to assess the recovery period after neuromuscular blockade by electromyographic F-wave analysis, a method that supplies more information about more proximal parts of the motor system than conventionally used methods, e.g., mechanomyography (MMG). In 20 neurosurgical ASA physical status I or II patients anesthesia was induced and maintained with IV fentanyl and midazolam. Patients were randomly assigned to receive either 0.25 mg/kg mivacurium (MV group, n = 10) or 0.1 mg/kg pancuronium (PC group, n = 10) intraoperatively. MMG monitoring of the adductor pollicis muscle was performed continuously. F waves were recorded at the abductor pollicis muscle of the contralateral hand at train-of-four (TOF) ratios of 0.1, 0.25, 0.5, 0.7, 0.75, 0.8, 0.85, 0.9, and 0.95. Recovery of F-wave amplitudes after neuromuscular blockade with pancuronium was significantly slower compared with mivacurium (P = 0.004) during the clinically important recovery period defined by MMG TOF ratios from 0.7 to 0.95. This electrophysiologic finding suggests a differential recovery of the motor system after administration of pancuronium and mivacurium not detected by MMG.

Adult↗

PubMed2003

Injectable neuromuscular blockade in the treatment of spasticity and movement disorders.

Neuromuscular blockade via injection of alcohol, phenol, or botulinum toxin reduces the tone of overactive muscles in order to restore the appropriate balance between agonists and antagonists. Such a restoration allows improved stretch and increased resting length and can reduce the likelihood of contracture. Alcohol or phenol, injected onto the motor nerve, denatures proteins and promotes axonal degeneration. The onset of action is within hours, whereas the duration of action is variable, ranging from 2 weeks to 6 months and beyond. The advantages of alcohol or phenol chemodenervation lie in their low cost and lack of antigenicity. The disadvantages include the technical difficulty of the injections and significant risk for pain as a result of treatment. Botulinum toxins, purified forms of Clostridium botulinum exotoxins, are injected directly into muscle, where they cleave one or more vesicle fusion proteins, thus blocking release of acetylcholine at the neuromuscular junction. Three commercial products--two of serotype A and one of B--are available. Each differs in its unit potency, side effects, and duration of action. On average, botulinum toxin has a clinical onset of action approximately 12 to 72 hours after injection, with a peak effect at 1 to 3 weeks. Effects then plateau for 1 to 2 months, with patients often requiring reinjection approximately every 3 months. Side effects may include local discomfort at the site of the injection and excessive weakness of the injected or nearby muscles, although more distant effects may occur. Antibody formation is a significant clinical concern and eventually obviates treatment benefit in approximately 5% of patients. Switching serotypes may be effective, at least temporarily. Consensus dosing guidelines have been developed and are presented within. Numerous studies have suggested that botulinum toxin has a role in the care of children with spasticity or dystonia related to cerebral palsy, and may improve equinus, gait, upper extremity use, comfort, and care. Evidence of functional improvement remains equivocal in the severely impaired child; however, there is evidence for improvement in less impaired children. The optimal candidate for injectable neuromuscular blockade is one who has a limited number of muscles that need treatment, who does not have fixed contracture, and who retains selective motor control. The ultimate goal of treatment for the hypertonic child is to maximize function, comfort, and independence. Hypertonia is only one aspect of the upper motoneuron syndrome, which includes both positive and negative symptoms. The treatment program, in which chemodenervation is only one tool, requires a multidisciplinary evaluation and individualized plan to address the whole patient.

Anti-Dyskinesia Agents↗

PubMed1980

Nitroglycerin and the neuromuscular blockade produced by gallamine, succinylcholine, d-tubocurarine, and pancuronium.

The finding in cats of prolonged pancuronium neuromuscular blockade in conjunction with intravenous infusion of nitroglycerin was previously reported by this laboratory. To expand on this finding the present study compared the effects of nitroglycerin on neuromuscular blockade produced by gallamine, d-tubocurarine, succinylcholine, and pancuronium, and further characterized the nitroglycerin-pancuronium interaction. The results indicate that of the relaxants studied only pancuronium neuromuscular blockade is prolonged, and that the prolongation is not due to altered plasma elimination of pancuronium. In vitro pancuronium blockade was not affected by nitroglycerin, suggesting the involvement of a metabolite in the block prolongation response. Reversibility of the prolonged pancuronium block by neostigmine is not influenced by nitroglycerin.

Animals↗