Gas Under Right Hemidiaphragm: A Rare Presentation of Unruptured Liver Abscess

A perforated liver abscess mimics hollow viscus perforations. It may be accompanied by pneumoperitoneum and peritonitis. A hollow viscus perforation appears to be the most common cause of gas under diaphragm. In about 10% of the cases, it can be due to rare abdominal and extra-abdominal causes. One of the causes could be intra-abdominal infection caused by gas-forming organisms. We are reporting a rare case of pneumoperitoneum resulting from an unruptured liver abscess in an old male with no comorbidity. An unruptured pyogenic right lobe liver abscess in a 70-year-old male was accompanied by X-ray flat plate abdomen features suggestive of free gas under the right hemidiaphragm. Culture of the pus drained from liver abscess grew Klebsiella sensitive to piperacillin and tazobactam, and antibiotic treatment was administered.

Paralysis of the right hemidiaphragm after liver transplantation: diagnosis and management / 中华肝胆外科杂志

Objective To review our experience in the diagnosis and management of paralysis of the right hemidiaphragm after liver transplantation. Methods 60 adult patients received liver transplantation from February 2001 to March 2007 in Sun Yat-sen Memorial Hospital were retrospectively analyzed. The pathophysiologic changes, clinical progress, and management of serious respiratory complications caused by post-transplant paralysis of the right hemidiaphragm were studied. Results Among 60 patients, 40 developed postoperative respiratory complications, and 5 were due to paralysis of the right hemidiaphragm. The 5 patients presented with paradoxical respiration and the ventilator supporting times were 14, 16, 34, 45, and 60 days, respectively. Tracheostomy was performed in 4. These patients developed pneumonia in 5, atelectasis in 4, acute respiratory distress syndrome (ARDS) in 4, hepatopulmonary syndrome in 4, and pulmonay interstitial edema in 3. Among the 5 patients, 4 patients survived and 1 patient died of ARDS and multiple organs failure 31 days after the transplantation. Conclusions After liver transplantation, strict monitoring of the respiratory function and timely use of a respirator for patients with the paralysis of the hemidiaphragm is very important. For patients with suspicious hemidiaphragm paralysis, tracheostomy should be decisively performed.

Neuromuscular Blocking Actions of Hexamethonium, Rocuronium and (-)Vesamicol / 대한마취과학회지

BACKGROUND: Hexamethonium (HM) and Rocuronium (R) are nAChR antagonists. However, there is some controversy as to whether R has a selective presynaptic effect. (-)Vesamicol (V) inhibits the transport of acetylcholine into the vesicles. This study compared the neuromuscular blockade of HM, R and V. METHODS: Hemidiaphragm-phrenic nerve preparations (male Sprague-Dawley rats [150-250 g]) were bathed in a Krebs solution maintained at 32oC and aerated with a mixture of 95% O2 and 5% CO2. Isometric forces were generated in response to 0.1 Hz, and 1.9-second 50 Hz with supramaximal stimulation (0.2 ms, rectangular) of the phrenic nerve. HM, R and V were added sequentially to achieve an 80-90% decrease in the ST. The ECs for ST, PTT and TF were calculated using a probit model. The antagonism indices of calcium (5 mM) and neostigmine (N) (250 nM) were assessed at the 85+/-5% level. RESULTS: The potency of ST, PTT and TF were respectively, 5.92, 3.56 and 1.99 mM for HM, 10.81, 5.27 and 4.4 1micronM for R, and 19.4, 15.2 and 13.3micronM for V. The neuromuscular blockades of R were reversed by N but not by calcium. Those of V were not reversed by either of them. Calcium and N inhibited the decrease in ST and TF by HM, respectively. CONCLUSIONS: The mechanism for how HM and R affect the neuromuscular blockade are different. V might not affect the release of acetylcholine.

Bovine pericardium as a lasting option tocorrect agenesis of the left hemidiaphragm:a five years follow-up / Uso do pericárdio bovino como opção duradoura para a correção da agenesia do hemidiafragma esquerdo: seguimento de cinco anos

Different surgical approaches for large congenital diaphragmatic defects have been described in the last fifity years. Synthetic patches have been proposed but have not always lead to good results due to reherniations, absence of growth of the patch, and future definitive operations. Few options of biological patches to reconstruct those large congenital defects are described in the literature, such as: dorsal muscle flap, lyophilized dura patch, small intestine submucosa and autologous fascia lata. There was no report of bovine pericardium patches as an alternative to treat congenital defects such as the total agenesis of the left hemidiaphragm, although experimental studies has shown that bovine pericardium seemed to be a very safe and resistant material to used in this congenital defect. We present a 4-years old girl that was re-operated with a patch of glutaraldehyde-preserved bovine pericardium after Silistic® patch had failed twice when she was born. We hypothesized that the bovine pericardium patch would be a lasting alternative to reconstruct agenesis of the left hemidiaphragm in this patient because of the attributes of the material: strength, elasticity, resistance to sutures and the possibility of growth. The aim of this communication is to present this biological material as a better and long-term alternative for correction of large congenital diaphragmatic defects, since our patient completed four years after the procedure without any deformities or respiratory complications.

Várias abordagens cirúrgicas têm sido descritas nos últimos cinqüenta anos para a correção dos grandes defeitos congênitos do diafragma. Material sintético tem sido proposto, mas não tem apresentado bons resultados devido às recidivas do defeito. O remendo sintético não cresce com a criança e apresenta necessidade de futuras reoperações. Poucas opções de materiais biológicos vêm sendo descritas na literatura para a correção dos grandes defeitos congênitos do diafragma, como: retalho muscular dorsal, duramáter liofilizada, submucosa de intestino delgado e fáscia lata autóloga. Não existem relatos na literatura a respeito do pericárdio bovino como opção ao tratamento dos defeitos congênitos do diafragma como agenesia total do hemidiafragma esquerdo, embora estudos experimentais mostram que o pericardium bovino parece ser material seguro e resistente que pode ser usado neste defeito congênito. Este é o relato de uma menina de 5 anos de idade que foi reoperada com remendo biológico de pericárdio bovino preservado em glutaraldeído, aos 4 meses de idade após duas tentativas frustradas de correção com remendo sintético (silicone). Os autores acreditam que o remendo de pericárdio bovino poderia ser opção mais duradoura para a correção da agenesia total do hemidiafragma esquerdo nesses pacientes devido às suas vantagens, como forte estrutura do material, elasticidade, resistência a suturas e possibilidade de crescimento. O objetivo deste relato é apresentar esse material biológico como melhor escolha, mais duradoura para correção dos grandes defeitos congênitos do diafragma, já que a criança completou quatro anos após o procedimento sem apresentar deformidade e ou complicações respiratórias.

The Effect of Nicorandil on the Pharmacodynamics of Rocuronium / 대한마취과학회지

BACKGROUND: Some investigators have shown that nicorandil, a K(ATP) channel opener, depresses the neuromuscular transmission contraction of the skeletal muscle. However, others have reported that it improves the recovery of vecuronium relaxation and the myotonic activity of muscle. This study investigated the effect of nicorandil on rocuronium relaxation. METHODS: Hemidiaphragm-phrenic nerve preparations were obtained from male Sprague-Dawley rats (150-250 g). The preparations were bathed in Krebs' solution containing in (mM): NaCl 118, KCl 5, CaCl2 2.5, NaHCO3 30, KH2PO4 1, MgCl2 1 and glucose 11. The preparations were, then maintained at 32 degrees C and aerated with a mixture of 95% O2 and 5% CO2. Isometric forces that were generated in response to 0.1 Hz, and, 50 Hz for 1.9 seconds with supramaximal electrical stimulation (0.2 msec, rectangular) to the phrenic nerve were measured using a force transducer. The single twitch tension (ST) and peak tetanic tension (PTT) were calculated as % inhibition of the control, and the tetanic fade (TF), as % increase in the PTT. Each preparation was exposed to one of the 6 nicorandil concentrations (0.0, 0.625, 1.25, 2.5, 5, 10 micrometer), and the adequate volume of the rocuronium solution was cumulatively added to the tissue bath for a desired rocuronium concentration until there was an 80-90% decrease in the ST. The effect of rocuronium at each concentration was allowed to reach a steady state before the tension parameters were measured. The EC5, EC25, EC50, EC75, and EC95 of rocuronium for the ST, PTT and TF were calculated using a probit model. The differences between the EC50 of rocuronium according to the nicorandil concentrations were tested using a t-test and a Bonferroni's correction. RESULTS: 1.25 and 2.5 micrometer nicorandil shifted the cumulative concentration-response curves for the TF of rocuronium to the right. 5 and 10 micrometer nicorandil shifted the cumulative concentration-response curves for the ST of rocuronium to the left. CONCLUSIONS: Lower concentration of nicorandil may help maintain the tetanic contraction during rocuronium relaxation.

The Effect of Kanamycin on Rocuronium Neuromuscular Blockade in Rat Hemidiaphragm-phrenic Nerve Preparations / 대한마취과학회지

BACKGROUND: Kanamycin has been shown to block neuromuscular transmission by reducing acetylcholine can release or blocking postsynaptic receptors. This study was undertaken to investigate whether kanamycin can potentiate rocuronium neuromuscular block. METHODS: Hemidiaphragm-phrenic nerve preparations were obtained from male Sprague-Dawley rats (150-250 g). Preparations were bathed in Kreb's solution of (mM): NaCl 118, KCl 5, CaCl2 2.5, NaHCO3 30, KH2PO4 1, MgCl2 1 and glucose 11 maintained at 32oC and aerated with a mixture of 95% O2 and 5% CO2. Isometric forces generated in response to 0.1 Hz and 50 Hz for 1.9 seconds with supramaximal electrical stimulation (0.2 msec, rectangular) to the phrenic nerve, were measured using a force transducer. The effects of drugs on single twitch tension (ST) and peak tetanic tension (PTT) were calculated as % inhibition of control and tetanic fade (TF), as % increase. Each preparation (n = 20) was exposed to one of 4 kanamycin concentrations (0.0, 1.0, 2.0, 4.0 mM), and an adequate volume of rocuronium solution was cumulatively added to the tissue bath to achieve a 80-90% reduction in ST. An adequate volume of kanamycin solution was cumulatively added to the other 5 preparations to achieve a 80-90% reduction in ST. The effect of kanamycin or rocuronium at each concentration was allowed to reach a steady state before tension parameters were measured. EC5, EC25, EC50, EC75, and EC95 of rocuronium and kanamycin for ST, PTT and TF were calculated using a probit model. Drug interactions were drawn using Berenbaum's additive isobole at 25% isobole, 50% isobole, and 75% isobole. Differences between EC50's of rocuronium at different kanamycin concentrations were tested using one way ANOVA with Tamhane post hoc analysis, P values of < 0.05 were regarded significant. RESULTS: Kanamycin shifted cumulative concentration-response curves to the right. The interactions of these drugs varied from additive to antagonistic or synergistic according to the magnitude of neuromuscular block, concentration of the drugs and the frequency of the stimulation. CONCLUSIONS: Kanamycin lowered the effective concentration of rocuronium, but the interaction between rocuronium and kanamycin was variable.

The Effect of Pefloxacin on Rocuronium-Induced Neuromuscular Blockade in Rat Phrenic Nerve-Hemidiaphragm Preparations / 대한마취과학회지

BACKGROUND: At the neuromuscular junction, pefloxacin (P) may exacerbate myasthenia gravis and reduce the tau of MEPC. So here we investigated the effect of P on the neuromuscular blocking action of rocuronium (R). METHODS: Hemidiaphragm-phrenic nerve preparations were obtained from male Sprague-Dawley rats (150-250 g). Preparations were bathed in Kreb's solution (in (mM): NaCl 118, KCl 5, CaCl2 2.5, NaHCO3 30, KH2PO4 1, MgCl2 1 and glucose 11), maintained at 32oC and then aerated with a mixture of 95% O2 and 5% CO2. Isometric forces generated in response to 0.1 Hz, and, 50 Hz for 19 seconds with supramaximal electrical stimulation(0.2 msec, rectangular) to the phrenic nerve, were measured with a force transducer. Single twitch tension (ST) and peak tetanic tension (PTT) were calculated as % reduction versus the control, and tetanic fade (TF), as a % increase. Each preparation was exposed to one of 4 P concentrations of Krebs' solution (0, 0.25, 0.5, 1.0 mM), and enough R solution was added to the tissue bath to achieve the desired R concentration. The effects of P and R were allowed to stabilize before measuring tension parameters. EC5, EC25, EC50, EC75, and EC95 of R for ST, PTT and TF were calculated using a probit model. The interactions between the two drugs were drawn with Berenbaum's additive isobole at 25% isobole, 50% isobole, and 75% isobole. Differences between EC50's of R according to P concentrations were tested by one way ANOVA with Tamhane for post hoc; P <0.05 was regarded as significant. RESULTS: The cumulative concentration-effect curves shifted to the right in ST, and to the left in TF as the concentration of P was increased. The interactions between these two drugs varied from additive to antagonistic according to the magnitude of relaxation effect, drug concentration, and the frequency of stimulation. CONCLUSIONS: P augmented the TF of R. Our results suggest that simultaneous 0.1 Hz and 50 Hz stimulations allow the neuromuscular blocking action of a drug to be correctly evaluated.

The Effect of Magnesium on the Verapamil Neuromuscular Blockade in Rat Phrenic Nerve-Hemidiaphragm Preparations / 대한마취과학회지

BACKGROUND: At the neuromuscular junction, magnesium acts on the release of acetylcholine and on the excitability of sarcolemma. Verapamil inhibits acetylcholine release and enhances the autodesensitization of acetylcholine receptor ion channels. So, we studied the effect of magnesium on the neuromuscular blocking action of verapamil. METHODS: Hemidiaphragm-phrenic nerve preparations were obtained from male Sprague-Dawley rats (200-300 g). Preparations were bathed in Kreb's solution of (mM): NaCl 118, KCl 5, CaCl2 2.5, NaHCO3 30, KH2PO4 1, MgCl2 1 and glucose 11, then maintained at 32 degrees C, and aerated with a mixture of 95% O2 and 5% CO2. Isometric forces generated in response to 0.1 Hz and 50 Hz for 1.9 seconds with supramaximal electrical stimulation (0.2 msec, rectangular) to the phrenic nerve, were measured with a force transducer. Single twitch tension (ST) and peak tetanic tension (PTT) were calculated as % reduction versus the control, and tetanic fade (TF) as a % increase. Each preparation was exposed to one of 4 magnesium concentrations of Krebs' solution (0.5, 1.0, 2.0, 3.0 [mM]), and the adequate volume of verapamil stock solution was added to the tissue bath to achieve the desired verapamil concentration. The effects of magnesium and verapamil were allowed to reach a steady state before tension parameters were measured. EC5, EC25, EC50, EC75, and EC95 of verapamil for ST, PTT and TF were calculated using a probit model. Differences between the EC50's of verapamil according to magnesium concentrations were tested using the Mann-Whitney U test with the Bonferroni correction, P < 0.05 was regarded as significant. RESULTS: The effective concentration of verapamil reduced at magnesium concentrations of 0.5, 2.0 and 3.0 (mM). CONCLUSIONS: The neuromuscular action of verapamil was found to be potentiated at either lower or higher magnesium concentrations.

Effects of Dexamethasone on Neuromuscular Transmission in a Phrenic Nerve-Hemidiaphragm Preparation in the Rat / 대한마취과학회지

BACKGROUND: MacFarlane and Rosenthal reported a case of acute quadriplegia after nondepolarizing muscular blocking agents in status asthmaticus patient treated with high doses of corticosteroid. Reports regarding the reactions of glucocorticoid treated muscles to neuromuscular blocking agents are sparse and inconsistent. The aims of this study were to examine the degree of muscle atrophy and its effects on sensitivity to neuromuscular blocking agents in relation to the dose and duration of dexamethasone. METHODS: Sixty Sprague-Dawley rats were divided into six groups. They were treated daily with dexamethasone 0.4 mg/kg and 4 mg/kg daily for 1 week or 3 weeks. The two control groups were treated with normal saline. The day after treatment, the dose-response curves of vecuronium were measured using a phrenic nerve-hemidiaphragm preparation. To classify muscle fiber, the diaphragm was stained for myofibrillar adenosine triphosphatase after alkaline and acid preincubation, and a morphometric examination was carried out. RESULTS: The diaphragmatic muscle in rats treated with long term, high dose dexamethasone showed significant atrophy. For the short term, low dose dexamethasone group, the ED50 and ED95 of vecuronium decreased 41.5% and 26.8% compared to those of the control group, respectively (P<0.05). However, the ED50 of vecuronium in the long term, high dose dexamethasone group increased 22.2% compared to that of the control group (P<0.05). CONCLUSION: This study suggests that sensitiviy to vecuronium was not modulated by dexamethasone-induced muscle atrophy. Quantitative changes of receptors at the neuromuscular junction or some anoother process might be responsible for this change.

Effect of Tetraethylammonium on the Contractile Reponse in the Isolated Rat Phrenic: Hemidiaphra / 대한마취과학회지

BACKGROUND: Recently, the phannacologic and therapeutic significance of various types of potassium channels are being realized. Thus it was attempted to delineate the role of voltage-gated K+ -channels on the excitation-contraction coupling in skeletal muscle. METHODS: The effects of tetraethylammonium, a well known K+ -channel blocker, on the electrically-evoked twitch response, train-of-four and tetanic stimulation, and the influence of various agents on the these effects were studied in the isolated rat hemi-diaphragm preparation. RESULTS: Tetraethylammonium (1 & 3 mM) increased the electrically-evoked twitch response, but the large dose (10 mM) decreased the twitch response. And tetraethylammonium decreased the TOF- and tetanus-ratio in a dose-related fashion. d-Tubocurarine(1 microM) decreased the twitch response, and tetraethylammonium recovered the d-tubocurarine-induced-depression of twitch response. When the Ca++(6x) and K+ (2x) concentration of the medium were increased, the twitch response caused by tetraethylammonium were slightly inhibited than that observed in the normal solution, but the fade phenomenon was potentiated. The tetraethylammonium (10 mM)-induced depression of twitch response were reduced by reducing the stimulus frequency to 0.01 Hz and choline (400 microM) treatment. And N-ethylmaleimide inhibited the tetraethylammonium-induced increment of twitch response and also potentiated the tetraethylammonium-induced fade phenomenon. However, it is noteworth the 4-aminopy- ridine, another K+ -channel bloker, potentiated the electrically-evoked twitch response but did not affect the TOF-and tetanusratio. CONCLUSION: These result indicate that tetraethylammonium elicited two districtive types of response in the rat phrenic-hemidiaphragm preparation. The potentiating effects of twitch response is mediated by blocking delayed K+ -rectifier channel and decreasing effects of twitch response, TOF-and tetanus-ratio is may be due to decreased the acetylcholine release from presynaptic nerve terminal.

Influence of Respiratory and Metabolic Acid-Base Changes on the Effect of Nondepolarizing Muscle Relaxants in the Rat Phrenic-hemidiaphragm / 대한마취과학회지

The effects and interactions of metabolic and respiratory acid-base changes on electrically-evoked twitch response, train-of-four and tetanic stimulation with pipecuronium (Pip), vecuronium (Vec) and atracurium (Tra) were studied in the isolated rat hemi-diaphragm preparation. pip (3X10(-7) - 4X10(-6) M), Vec (3X10(-6) - 15X10(-6) M) and Tra (10(-6) - 3X10(-5) M) decreased the electrically-evoked (phrenic nerve stimulation, 0.1 Hz, 0.2 ms, 10 V) twitch response in a dose related fashion and Pip was more potent than Vec and Tra. In the alkali state (pH 7.6 or high HCO3 ), the decrements of twitch response, train-of-four and tetanus ratio induced by Pip (1.5uM) were potentiated, but the effects of Vec or Tra were markedly intensified by acid midium (pH 7.2 or low HCO3 ). And also, decreasing pH by increasing PCO2 or by decreasing HCO3 intensified the effects of Vec and Tra, whereas it reversed by Pip. Conversely, increasing pH by decreasing PCO2 or by increasing HCO3 antagonized the effects of Vec and Tra, whereas it potentiated the Pip effect. On the basis of these finding, the result of the present study suggest that neither PCO2 nor HCO3 has a specific action, but that changes in pH may be responsible for the results. In addition, the differences of the above results by each drugs may not be due to the number of quaternary ammonium of the agents. And also, indicate that the effective site of the influence of the acid-base change upon the neuromuscular blocking effects might be prejunctional nerve terminal.

Effect of Diltiazem and Verapamil on Pipecuronium-and Atracurium-induced Neuromuscular Blockade / 대한마취과학회지

The effects and interactions of pipecuronium and atracurium with diltiazem and verapalmil on the electrically-evoked twitch response, train-of-four and tetanic stimulation were studied in the isolated rat phrenic-hemidiaphragm preparation. Pipecuronium (3X10(-7) -4X10(-6)) and atracurium (10(-6) -3X10(-5) M) decreased the electrically-evoked twitch response, train-of-four and tetanus ratio in a dose-related fashion and the pipecuronium was more potent than atracurium. The inhibitory effects of pipecuronium and atracurium were potentiated by pretreatment of 5 uM diltiazem and verapamil, Ca++-channel blokers, in which the concentration of diltiazem or verapamil has no obvious effect on the twitch response itself. Futhermore, it is noteworthy that the inhibitory effects of pipecuronium and atraeurium were markedly potentiated by 150 uM hemicholinium pretreatment. On the basis of these findings, the results of present study suggests that the muscle relaxation by pipecuronium and atracurium is mediated by pre- and post-junctional receptor blockade, and that diltiazem or verapamil intensifies neuromuscular blockade produced by these musele relaxants. The potentiating effect of diltiazem or verapamil may be due to blocking influx of calcium and/or release of acetylcholine from presynaptic nerve terminals.

A Study on the Blocking Effect of Diltiazem and Verapamil in the Isolated Rat Phrenic - Hemidiaphragm / 대한마취과학회지

The effects of diltiazem and verapamil on the electrically-evoked twitch response, train-of- four and tetanic stimulation were studied in the isolated rat hemidiaphragm preparation. Diltiazem(3-150 pM) and verapamil(3-100 pM) increased the electrically-evoked(nerve stimulation, 0.1 Hz, 0.5 ms, 10 V) twitch responses in a dose-related fashion and diltiazem was more potent than verapamil. But, the large doses of diltiazem(150-300 uM) and verapamil(100-300 uM) decreased the twich responses. And the effects of diltiazem and verapamil were not effected by reducing the extracellular calcium from 2.5 to 1.25 mM. Diltiazem and verapamil decreased the train-of-four and tetanus ratio as well as the d-tubocurarine in a dose-related fashion. d-Tubocurarine, a specific nicotinic antagonist, decreased twitch response, and the potentiating twitch response of diltiazem was significantly inhibited by pretreatment of d-tubocura- rine. Furthermore, it is noteworth that the inhibitory effects of d-tubocurararine were markedly potentiated by diltiazem. In cases of the direct(muscle, 0.1 Hz, 5 ms, 10 V) stimulation, diltiazem and verapamil decreaaed the electrically-evoked twitch response with dose dependently. These results indicate that diltiazem and verapamil elicited two distinctive types of twitch response in the rat phrenic-hemidiaphragm preparation. The potentiating effect of twitch response is mediated by the acetylcholine release from the prejunctional nerve terminal and the inhibiting effect may be due to blcking influx of calcium and/or release of acetylcholine from presynaptic nerve terminals.

Effect of Nifedipine on the Contractile Response in the Isolated Rat Phrenic - Hemidiaphragm / 대한마취과학회지

The effects of nifedipine, a dihydropyridine Ca2+ antagonist, on the eleetrically-evoked twitch response, train-of-four and tetanic stimulation were studied in the isolated rat hemidiaphragm preparation. Nifedipine, in concentrations ranging from 3 to 100 uM, increased the electrically-evoked (nerve stimulation, 0.1 Hz, 0.5 ms, 10 V) twitch response and train-of-four ratio in a dose-relat- ed fashion, and the potentiating effects were inhibited by d-tubocurarine preteratment. The effect of nifedipine was not affected by reducing the extracellular Ca2+ concentration from 2.5 mM to 1.25 mM. In cases of the direct(muscle, 0.1 Hz, 5 ms, 10 V) stimulation, nifedipine increased the twitch response in a dose-dependent manner, but the amplitudes were smaller than those in indirect stimulation. Nifedipine 30 uM potentiated the contractile response induced by 70 mM KC1 and caffeine(10 mM)-induced isometric contractile responses were markedly potentiated by nifedipine treatmeat. Nifedipine 70 upotentiated the effect of l mM caffeine on the electrically-evoked twitch response and the potentiating effect was also seen in reverse treatment. On the basis of these findings, the result of present study suggests that the potentiating contractile response by nifedipine is mediated by two distinctive mechanisms. One is the acetylcholine release from presynaptic nerve terminal and the other may be due to the releases of Ca2+ in sarcoplasmic reticulum.

Effect of Diltiazem on Pancuronium - and Vecuronium - induced Neuromuscular Blockade / 대한마취과학회지

The effects and interactions of pancuronium and vecuronium with diltiazem on the electri- cally-evoked twitch response, train-of-four and tetanic stimulation were studied in the isolated rat hemi-diaphragm preparation. Pancuronium(3 X 10(-7) -10(-5) M) and vecuronium(3 X 10(-6)-15 X 10(-6) M) decreased the electrically evoked(nerve stimulation, 0.1Hz, 0.5ms, 10V) twitch response, train-of-four and tetanus ratio in a dose-related fashion and pancuronium was more potent than vecuronium. The inhibitory effects of pancuronium and vecuronium were potentiated by pretreatment with 5 & 10 uM diltiazem, a Ca++-channel blocker, in which the concentration of diltiazem has no obvious effects on the twitch response itself. Furthermore, it is noteworth that the inhibitory effects of pancuronium and vecuronium were markedly potentiated by 150 uM hemicholinium pretreatment. In cases of the direct(muscle, 0.1 Hz, 5 ms, 10 V) stimulation, pancuronium and vecuronium decreased the electrically evoked twitch response dose dependently, but the amplitudes of inhibition were less than those in indirect(nerve) stimulation. The inhibitory effects were not affected by diltiazem pretreatment except low doses of vecuronium. On the basis of these findings, the result of the present study suggests that the muscle relaxation by pancuronium and vecuronium is mediated by pre- and post-junctional receptor blockade, and that diltiazem intensifies neuromuscular blockade produced by muscle relaxants. The potentiating effect of diltiazem may be due to blocking influx of calcium and/or release of acetylcholine from presynaptic nerve terminals.

Effect of Diltiazem on Pancuronium - and Vecuronium - induced Neuromuscular Blockade / 대한마취과학회지

The effects and interactions of pancuronium and vecuronium with diltiazem on the electri- cally-evoked twitch response, train-of-four and tetanic stimulation were studied in the isolated rat hemi-diaphragm preparation. Pancuronium(3 X 10(-7) -10(-5) M) and vecuronium(3 X 10(-6)-15 X 10(-6) M) decreased the electrically evoked(nerve stimulation, 0.1Hz, 0.5ms, 10V) twitch response, train-of-four and tetanus ratio in a dose-related fashion and pancuronium was more potent than vecuronium. The inhibitory effects of pancuronium and vecuronium were potentiated by pretreatment with 5 & 10 uM diltiazem, a Ca++-channel blocker, in which the concentration of diltiazem has no obvious effects on the twitch response itself. Furthermore, it is noteworth that the inhibitory effects of pancuronium and vecuronium were markedly potentiated by 150 uM hemicholinium pretreatment. In cases of the direct(muscle, 0.1 Hz, 5 ms, 10 V) stimulation, pancuronium and vecuronium decreased the electrically evoked twitch response dose dependently, but the amplitudes of inhibition were less than those in indirect(nerve) stimulation. The inhibitory effects were not affected by diltiazem pretreatment except low doses of vecuronium. On the basis of these findings, the result of the present study suggests that the muscle relaxation by pancuronium and vecuronium is mediated by pre- and post-junctional receptor blockade, and that diltiazem intensifies neuromuscular blockade produced by muscle relaxants. The potentiating effect of diltiazem may be due to blocking influx of calcium and/or release of acetylcholine from presynaptic nerve terminals.