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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have examined the effects of bupivacaine and lignocaine on myocardial metabolism in the rat isolated heart-lung preparation. Bupivacaine 1, 5 or 25 micrograms ml-1 or lignocaine 4, 20 or 100 micrograms ml-1 was administered 5 min after the start of perfusion. Both bupivacaine 25 micrograms ml-1 and lignocaine 100 micrograms ml-1 reduced heart rate significantly. Bupivacaine 25 micrograms ml-1 was associated with a higher incidence of arrhythmias than the other groups. Three hearts in the bupivacaine 25 micrograms ml-1 group (n = 8) and two hearts in the lignocaine 100 micrograms ml-1 group (n = 8) failed (zero cardiac output) at the end of the experiment. Although there were no significant differences in myocardial lactate and glycogen concentrations between groups, ATP content in the bupivacaine 25 micrograms ml-1 and lignocaine 100 micrograms ml-1 groups was significantly less than that in the control group. The results suggest that myocardial depression and subsequent metabolic deterioration occurred with both the high doses of local anaesthetics; these findings do not account for the apparent increased cardiotoxicity of bupivacaine.
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PMID:Functional and metabolic effects of bupivacaine and lignocaine in the rat heart-lung preparation. 224 20

The aim of this study was to assess the value of peridural thoracic analgesia (ATP) to prevent pain observed during pleural symphysis with tetracycline (STP) for pneumothorax (PNO). 12 patients (age 27 +/- 6 years) having a spontaneous PNO benefited from 13 SPT (1 gm, tetracycline diluted in 60 cc of normal saline) under cover of an APT (at the D5-D6 level) with Fentanyl (0.1 mg) and Bupivacaine 0.5% adrenalin (1 mg/kg). The protocol was used on three successive days. Repeated determinations of blood bupivacaine levels were performed in 9 patients on the first day. No patient had an intolerable pain which required injection of parenteral morphine and/or an interruption of the protocol. For two patients (one of them having a right symphysis and then a left symphysis one month later) the treatment sessions to achieve a symphysis were totally painless. 10 patients experienced moderate pain, mainly on the first day, which was relieved by reinjection of peridural bupivacaine (25 mg) (n = 9) or by the parenteral injection of non morphine analgesia (n = 1). No patient had a respiratory depression, collapse or bradycardia. The blood bupivacaine levels were always significantly less than the toxic levels (1.6 mg). The results observed suggest that APT, (Fentanyl and Bupivacaine) is an effective method, non toxic and well tolerated for the prevention of intolerable pain which is seen in SPT for PNO.
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PMID:[Pleural symphysis with tetracyclines for pneumothorax. The value of thoracic peridural analgesia]. 203 49

The effects of local anesthetics in depressing myocardial contractility were studied in isolated guinea pig right ventricular papillary muscles. Bupivacaine and etidocaine, 4 and 10 microM, showed reverse frequency-dependent depression of contractility, that is, less significant depression of contractility at higher stimulation frequencies (2-3 Hz) than at lesser frequencies (less than 1 Hz). Lidocaine, 40 microM, demonstrated a similar trend. In contrast, the normal action potential maximum rate of depolarization (Vmax), a measure of sodium channel conductance, was significantly more depressed at 2-3 Hz by bupivacaine and etidocaine than by lidocaine. Consequently, contractile depression could be overcome only at higher stimulation frequencies, at which conduction was depressed. To explore the mechanism of the contractile depression, local anesthetic effects were studied on slow (calcium channel-mediated) action potentials in partially depolarized papillary muscles. Etidocaine and bupivacaine, 4 and 10 microM, and lidocaine, 40 and 100 microM, caused a marked depression of the late-peaking contractile responses, attributed to Ca2+ release from the sarcoplasmic reticulum. In contrast, only 10 microM bupivacaine caused any significant depression of the slow action potential rate of depolarization (to 89% of control), consistent with a possible small depression of Ca2+ entry.
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PMID:Depression of myocardial contractility in vitro by bupivacaine, etidocaine, and lidocaine. 242 88

The effects of lidocaine (25, 50 and 100 micrograms/ml) and bupivacaine (5, 10, and 20 micrograms/ml) on amplitude, velocity, and contraction frequency were studied in monolayer cultures of spontaneously beating chick embryo ventricular cells. The physiologic parameters of contraction frequency, amplitude, and velocity of shortening were measured with an optical-video system. Studies were also carried out in the presence of 1 microM tetrodotoxin (TTX) to isolate effects caused by TTX-sensitive ion channel blockade from other possible mechanisms of action of local anesthetics. Lidocaine and bupivacaine produced concentration-dependent, reversible decrements in contraction frequency, amplitude, and velocity of contraction. Bupivacaine demonstrated a 5-fold higher potency for depression of contractile properties than lidocaine. At a high concentration, bupivacaine (20 micrograms/ml) produced significantly more depression in all three measured parameters than did lidocaine (100 micrograms/ml). In the presence of predominantly Na+ channel blockade by TTX, bupivacaine (10 micrograms/ml) produced further decreases in amplitude and velocity of shortening. In the presence of TTX, lidocaine (50 micrograms/ml) produced a further decrease in amplitude of contraction, but no significant change in contraction frequency or velocity of contraction. It is well known that local anesthetics block Na+ channels of excitable membranes. The authors observations suggest that both lidocaine and bupivacaine have at least one locus of action at a site other than a TTX blockade site.
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PMID:Contractility effects of local anesthetics in the presence of sodium channel blockade. 256 53

The effects of bupivacaine and lidocaine on cardiac conduction were compared in guinea pig ventricular muscle. Membrane potential was controlled using a single sucrose gap voltage clamp technique, and the maximum upstroke velocity of the action potential (Vmax) was used as an indicator of peak sodium current. Bupivacaine blocked cardiac sodium channels in a time- and voltage-dependent fashion. Although bupivacaine has a low affinity for rested and activated sodium channels, it avidly blocks inactivated channels (Kd = 9 X 10(-7) M). Bupivacaine-associated channels do not conduct and have their voltage dependence of inactivation shifted by about 33 mV to more negative potentials. At bupivacaine concentrations above 0.2 micrograms/ml, a substantial fraction of the channels become blocked during the cardiac action potential, while recovery from block during diastole proceeds relatively slowly with a time constant (tau) of 1,557 +/- 304 ms (n = 8). Thus, bupivacaine blocks sodium channels in a fast-in-slow-out fashion, and substantial block accumulates at 60-150 beats/min. In comparison, 5-10 micrograms/ml lidocaine also blocks a substantial fraction of channels during the action potential, but diastolic recovery from block is more rapid (tau = 153.8 +/- 51.2 ms, n = 4). Thus, lidocaine blocks channels in a fast-in-fast-out fashion. Consequently, even at toxic doses of lidocaine (i.e., 10 micrograms/ml), little accumulation of block occurs at normal heart rates. Sodium channel block by bupivacaine can be minimized by reducing heart rate, hyperpolarization, and shortening of action potential duration. However, alteration of these variables over clinically applicable ranges does not produce marked changes in bupivacaine effect. Our results provide a possible explanation for the clinical observation that when bupivacaine accidently gains access to the general circulation, cardiac conduction can be depressed seriously and such depression may be difficult to reverse.
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PMID:Mechanism for bupivacaine depression of cardiac conduction: fast block of sodium channels during the action potential with slow recovery from block during diastole. 258 Apr 63

Morphine and bupivacaine have been administered caudal via to 28 children between 2 and 12 years old for the postoperative pain treatment. All of them were submitted to general anesthesia and randomly divided into 3 groups depending on the drug administered caudal via. a) Morphine group (n = 10): morphine chlorhydrate 50 micrograms/kg (0.5 ml/kg of morphine solution 100 micrograms/ml). b) Bupivacaine group (n = 10): bupivacaine 0.5%, 2.5 mg/kg. c) Control group (n = 8): no drug administered. Pain evaluation was made on the basis of physiological and clinical data. In the morphine group, the postoperative time until analgesia was required 20 +/- 5 hours and analgesia has been significantly better (p less than 0.001) than bupivacaine and control group. The number of analgesic drug needed during the postoperative 24 first hours was also less in morphine group. No differences on postoperative complications were seen among the 3 groups and no case of respiratory depression was observed. It is concluded that epiduro-caudal morphine provides effective and prolonged analgesia and can be safely used for postoperative pain treatment in pediatric urologic surgery. However, we believe, that larger series of patients will provide better information of its efficacy and other side effects.
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PMID:[Postoperative analgesia using caudal morphine in pediatric surgery: randomized double-blind study compared with bupivacaine]. 267 19

The effects of bupivacaine, a long-acting local anesthetic, were studied on action potentials of spontaneously beating sinus venosus of the frog Caudiverbera caudiverbera. The study was accomplished by recording transmembrane potentials of pacemaker transitional cells. Action potentials of these cells are known to have both a fast and a slow ionic component. Bupivacaine (1 X 10(-5) M to 1 X 10(-4) M) caused a reversible negative chronotropic effect accompanied by decrease of diastolic depolarization rate and prolongation of sinus cycle length. This drug also markedly depressed rate of rise [(dV/dt)max] of action potentials. Tetrodotoxin (TTX) (1 X 10(-7) M) induced similar effects than bupivacaine. In atropine-treated sinus venosus the effect of bupivacaine on spontaneous rate of firing was less intense. However, in cells exposed to both drugs, a greater depression of (dV/dt)max and of other electrophysiological parameters such as action potential amplitude, overshoot and maximum diastolic potentials was observed. Depression of phase 4 depolarization seems difficult to be explained in view of the complex nature of the ionic currents underlying pacemaker depolarization. Reduction of (dV/dt)max caused by bupivacaine and mimicked by TTX was ascribed to blockade of sodium channels. It was concluded that bupivacaine by decreasing (dV/dt)max of transitional cells and by depressing diastolic depolarization slows down conduction of impulses arising from primary cells and that this action may contribute to its cardiac toxicity.
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PMID:Electrophysiological effects of bupivacaine on transitional pacemaker cells of the frog heart. 282 42

Empirical i.v. doses of lignocaine or bupivacaine of equal local anaesthetic potency were administered to halothane-anaesthetized dogs. Both local anaesthetics caused the expected depression of global haemodynamic function. Regional myocardial systolic shortening was depressed similarly by both agents. Regional myocardial dysfunction, seen as post-systolic shortening, occurred to a similar extent with both lignocaine and bupivacaine. Coronary blood flow and coronary perfusion pressure were significantly correlated during the administration of lignocaine; bupivacaine had erratic effects on coronary blood flow and no correlation between coronary blood flow and coronary perfusion pressure was seen. These results suggest that regional myocardial dysfunction occurs with both local anaesthetics and does not account for the apparent increased cardiotoxicity of bupivacaine. Bupivacaine did, however, cause wider individual variations compared with lignocaine with respect to coronary blood flow.
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PMID:Effects of lignocaine and bupivacaine on regional myocardial function and coronary blood flow in anaesthetized dogs. 337 51

In a previous report, the incidence of tourniquet pain was found to be 25% with bupivacaine and 60% with tetracaine (P less than 0.05) spinal anesthesia. On the other hand, tetracaine is more potent than bupivacaine in abolishing the single-compound action potential in vitro in isolated nerves. These conflicting observations may be reconciled if bupivacaine produced greater frequency-dependent conduction blockade of nerve action potentials. This hypothesis was tested in C fibers of isolated, desheathed rabbit vagus nerves. The nerves were supramaximally stimulated at frequencies of 9 or 15 Hz. After a control period, the nerves were exposed to bupivacaine (0.2 mM) or tetracaine (0.02 mM) for 30 minutes. The local anesthetics were then washed out by continuous constant-rate perfusion. The decline and recovery of the first and last action potential amplitudes of the train were measured. Bupivacaine and tetracaine produced similar depression of the first action potential of the 9-Hz and 15-Hz trains. However, bupivacaine caused a delayed recovery of the last action potential of the 15-Hz train but not of the 9-Hz train. These results show that bupivacaine produces greater frequency-dependent conduction blockade of C fibers than does tetracaine. These findings offer a possible explanation as to why spinal anesthesia with bupivacaine results in a lower incidence of tourniquet pain than tetracaine.
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PMID:Decreased incidence of tourniquet pain during spinal anesthesia with bupivacaine. A possible explanation. 341 93

Since its introduction to North America in 1942, the use of epidural catheter analgesia has increased dramatically. Improved equipment, methods and medications have broadened its application to include among others, surgical anesthesia, chronic pain relief and the management of postoperative pain. Numerous techniques for epidural puncture and insertion of the catheter have been described. Although complications have been associated with placement of an epidural catheter, these are rare when performed by an experienced anesthesiologist. Epidural analgesia was first accomplished by blockade with local anesthetics. Bupivacaine has been called the local anesthetic of choice for epidural infusion. Bolus administration of epidural local anesthetics gives effective analgesia; however, its use is limited by brief duration and occasionally severe hypotension. Epidural local anesthetics have been administered by continuous infusion in an attempt to minimize side effects. Nevertheless, hypotension, as well as motor block, numbness, nausea and urinary retention have occurred. Epidural analgesia with local anesthetics is effective in relieving postoperative pain, but its safety and feasibility have been questioned because of the frequent, potentially serious side effects. These problems led to trials of epidural narcotics for postoperative pain management. The exact site of action of epidural narcotic analgesics is debatable; however, the bulk of evidence supports a direct spinal action. Epidural narcotics appear to specifically inhibit nociceptive stimuli. The prolonged and profound analgesia that occurs with epidural narcotics relative to parenteral administration is due to a higher concentration of drug reaching the CSF through the epidural route. Since nervous transmission is not completely blocked this technique cannot provide anesthesia during operation. Morphine has been the most frequently used narcotic for epidural analgesia. Results of several recent, randomized double-blind studies have shown that epidural narcotics give adequate analgesia comparable with that observed with epidural bupivacaine. Epidural morphine provides a greater duration of analgesia and may cause fewer side effects. Improved analgesia has been reported when epidural narcotics are used in combination with local anesthetics. Continuous administration of low dosage epidural narcotics has been shown to have less frequent side effects than bolus administration. Nevertheless, pruritus, urinary retention, hypotension and severe respiratory depression have been reported with both methods.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Epidural catheter analgesia for the management of postoperative pain. 351 98


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