Search PubMed⌕ Search

Biomedical subjects

H Wulf

Publications and source records attributed to H Wulf.

At least 127 records · Page 7Linked to original sources
PubMed1994

The stability of mixtures of morphine hydrochloride, bupivacaine hydrochloride, and clonidine hydrochloride in portable pump reservoirs for the management of chronic pain syndromes.

The physical and chemical stability of a combination of drugs commonly administered into the epidural or intrathecal space for the treatment of chronic pain was investigated. The concentrations of bupivacaine hydrochloride, morphine hydrochloride, and clonidine hydrochloride were measured using high performance liquid chromatography. The solutions were stored in reservoir bags for up to 90 days. No macroscopic or microbiological signs of precipitation, change in color, or contamination were observed, and pH remained stable. None of the three drugs declined in concentration during the observation period. A small increase in concentration of all three drugs did occur over time, most probably due to evaporation processes. In conclusion, no problems in physical or chemical stability are to be expected when combining morphine, bupivacaine, and/or clonidine for long-term epidural or intrathecal administration. In the case of clinically apparent loss of analgesic efficacy, other mechanisms should be considered.

Bupivacaine↗
PubMed1994

Functional interaction between local anaesthetics and calcium antagonists in guineapig myocardium: 1. Cardiodepressant effects in isolated organs.

Both local anaesthetics and calcium antagonists depress cardiac function. Therefore, we have studied the interaction of these compounds in the isolated myocardium of guineapigs. The negative inotropic effect of various local anaesthetics was investigated in left atria in the absence or presence of nitrendipine 10(-7) mol litre-1 (n = 7-8 in each group). In addition, the effect of bupivacaine was studied in the presence of several calcium antagonists. The factor by which the negative inotropic potency (EC50) of local anaesthetics was enhanced significantly in the presence of nitrendipine varied from mean 1.2 (SD 0.2) (benzocaine) to 3.0 (0.6) (bupivacaine). The EC50 of bupivacaine was lowered by all calcium antagonists. The potentiation factor varied from 1.4 (0.4) (verapamil) to 3.3 (0.6) (nifedipine). The effects of benzocaine (n = 12) and bupivacaine (n = 11) on the working heart were assessed either alone or after pretreatment with nifedipine 10(-8) mol litre-1. The effects of benzocaine on contractility remained unaltered in the presence of nifedipine, whereas the negative inotropic effect of bupivacaine increased significantly (for example, a 20% reduction in left ventricular maximum dP/dt occurred with bupivacaine 1.75 (0.16) x 10(-6) mol litre-1 alone compared with 1.1 (0.22) x 10(-6) mol litre-1 when combined with nifedipine). We conclude that the effects of some local anaesthetics, for example bupivacaine, on cardiac contractility are enhanced in the presence of calcium antagonists. The relevance of this interaction in patients remains to be determined.

Anesthetics, Local↗
PubMed1994

Functional interaction between local anaesthetics and calcium antagonists in guineapig myocardium: 2. Electrophysiological studies with bupivacaine and nifedipine.

The negative inotropic effect of local anaesthetics is potentiated by several calcium antagonists in guineapig myocardium [1]. Therefore, we studied which effects on cardiac ionic currents could be responsible for this interaction. Concentration-response curves for bupivacaine were studied in isolated guineapig atria and papillary muscles (slow action potentials). Effects on action potentials were assessed in the absence (n = 7 atria, n = 8 papillary muscles) or presence of nifedipine (8 x 10(-8) mol litre-1 in n = 8 atria, 10(-8) mol litre-1 in n = 8 papillary muscles). The effect on the Ca2+ current was assessed directly using the patch-clamp technique in guineapig ventricular myocytes. Bupivacaine reduced contractile force and upstroke velocity of atrial action potentials. Only the negative inotropic effect was potentiated in the presence of nifedipine. Force and upstroke velocity of slow action potentials were diminished by bupivacaine. Both variables were affected at significantly smaller concentrations of bupivacaine when given in combination with nifedipine. The Ca2+ current was reduced significantly by bupivacaine 5 x 10(-5) mol litre-1 (mean -18 (SD 7)%, n = 9). Its effect was accentuated in the presence of nifedipine 10(-9) mol litre-1 (-47 (4)%, n = 7). Bupivacaine 3 x 10(-4) mol litre-1 given alone exerted a comparable effect (-53 (4)%, n = 4). Variables indicative of Ca2+ channel function (contractile force, upstroke of slow but not normal action potentials, Ca2+ inward current) revealed potentiation of the effects of bupivacaine by nifedipine.

Action Potentials↗
PubMed1994

Plasma concentrations of bupivacaine after lumbar sympathetic block.

To determine the pharmacokinetics of local anesthetics after lumbar sympathetic blocks, total and free (unbound) plasma concentrations of bupivacaine in venous blood samples were measured in 12 patients using a high-performance liquid chromatography (HPLC) technique. Administration of 30 mL of plain bupivacaine 0.175%, via two needles, resulted in a maximum total plasma concentration of 0.2-1.0 mg/L (mean 0.49 mg/L). These maximum concentrations were reached 10-45 min after the injection (mean 24 min). There were no clinical signs of central nervous system (CNS) toxicity attributable to local anesthetics. All patients showed hemodynamic stability after the blocks. We conclude that the absorption of local anesthetics after lumbar sympathetic blocks is slow compared to stellate ganglion or intercostal blocks, and does not result in toxic plasma concentrations. These blocks might well be performed in outpatients.

Adult↗
PubMed1993

[Potassium substitution during coronary surgery: K(+)-Mg+(+)-aspartate-complex (Inzolen) versus potassium chloride].

Potassium loss may cause arrhythmias and cardiac injury in patients undergoing heart surgery with cardiopulmonary bypass (CPB). In a prospective, randomized trial two different methods of potassium substitution were investigated regarding their influence on cardiac rhythm following reperfusion. Patients received either potassium chloride (Group I, n = 102) or potassium magnesium aspartate (Inzolen, group II, n = 105) to achieve intraoperative serum potassium concentrations of 4.5 mmol/l. St. Thomas cardioplegic solution was used. CPB was performed in moderate hypothermia (28-32 degrees C) with a non-pulsatile pump flow, a membrane oxygenator and a single two-stage venous catheter. The two study groups were comparable with regard to biometric data, preoperative state, duration of operation, ischemia and clinical outcome. In 6 patients in group I and in 3 patients in group II perioperative myocardial infarction was diagnosed based on ECG and CK-MB findings. One patient in each group died during the postoperative hospital stay. At the time of declamping mean serum potassium concentration was 4.9 +/- 0.7 mmol/l in group I and 4.8 +/- 0.5 mmol/l in group II (n.s.). The concentration of magnesium was significantly lower in the potassium chloride substitution group (1.48 mmol/l) compared to the other group (2.33 mmol/l) (p < 0.05). No significant differences in cardiac electric activity were observed between the two groups. The incidence of ventricular fibrillation in the early reperfusion period was 37% versus 45% (n. s.). In both groups patients with a potassium value of < 4.5 mmol/l showed a significantly higher incidence of ventricular fibrillation. Five percent of the patients had bradycardia requiring temporary pacing.(ABSTRACT TRUNCATED AT 250 WORDS)

Aspartic Acid↗
PubMed1993

[The potential dependence of the effect of bupivacaine and ropivacaine on the heart. In-vitro studies on the effect of local anesthetics on the force of contraction and the action potential in left guinea pig atria].

The cardiotoxicity of long acting local anaesthetics is still a matter of controversy. Therefore, the effects of bupivacaine and ropivacaine on cardiac contractility and electrophysiologic parameters were evaluated in the presence of different extracellular potassium concentrations. METHODS. In strips from left atria of guinea pigs action potentials were induced to obtain cumulative dose response curves for bupivacaine (racemic mixture) and ropivacaine (S-enantiomer). Effects on force of contraction and parameters of the action potential (especially maximum upstroke velocity, dV/dtmax, as an indirect measure of fast sodium channel function) were compared for low (2.7 mM) and high (8.7 mM) extracellular K+ concentrations (n = 7-8). RESULTS. At low K+ concentration, bupivacaine and ropivacaine depressed force of contraction and dV/dtmax in a dose-dependent manner. At higher local anaesthetic concentrations, action potential amplitude decreased and action potential duration was prolonged. There was no influence on the resting membrane potential (Tables 2, 3). At high K+ concentration, both local anaesthetics induced effects similar to those observed with low K+, but the dose-response curves for contractility and dV/dtmax were shifted leftward. The EC50 of bupivacaine for the negative inotropic effect and, analogously, for dV/dtmax was approximately 10 times lower. Similar results were observed for ropivacaine (Figs. 1, 2). CONCLUSION. This study confirms the dependence of the cardiodepressive effects of bupivacaine on the extracellular K+ concentration (i.e. membrane potential). The present investigation shows a similar dependence for the effects of ropivacaine, a new long-lasting local anaesthetic. Our results concerning the potential dependency of dV/dtmax depression are compatible with the binding of bupivacaine to the inactivated state of the sodium channel protein preferentially (modulated receptor hypothesis). Thus accumulation of block will occur if stimulation frequency is in an appropriate range. Though we found striking analogies between potential dependency of dV/dtmax depression and negative inotropic effect, there is no firm evidence that the sodium channel block by bupivacaine or ropivacaine substantially participates in the latter effect. An influence on other ionic channels such as the calcium channel remains to be evaluated.

Action Potentials↗
PubMed1993

[Computer-aided anesthesia monitoring. Experiences with the use of three systems in heart surgery].

Basic monitoring in cardiac anaesthesia embraces at least 19 different parameters of haemodynamics and blood gas analysis. In special cases additional measurements may be desirable, providing a total of up to 44 variables displayed on various monitors, as depicted in Fig. 2. The recording of such an amount of data is only feasible with automated recording systems. Therefore, in the past 6 years we have introduced three different computer systems to our cardiac anaesthesia workplaces. The experiences in their handling are reported. MATERIAL AND METHOD. Three systems were investigated: (1) System S 4000 (Siemens, Germany), based on a central processor unit (PDP 11, DEC, Japan) connected with 20 bedside input/output terminals and Sirecust 404a monitors (Siemens). The system collected the data in a ring buffer with a capacity for about 24-48 h. (2) Patient Care Manager (PCM; Siemens, Germany), a single workplace system based on an IBM-compatible personal computer (PC) with the operating system environment DOS 5.0/Windows 3.0. In our test configuration it was connected with a Sirecust 1281 monitor (Siemens). (3) Monitor-Data-Manager (MDM) (our own development). This single workplace system is also based on an IBM-compatible PC running under DOS and was connected to four different monitors used in our cardiac surgery operating theatre (Fig. 2). A second computer (Sirecust S 425, Siemens) served as an interface between the two 404 monitors (not featuring a serial output like RS 232) and the PC. The self-developed program for that interface was memory resistant and executable with three key presses when the anaesthetic record was started. The three systems were compared with regard to their ease of use, function and practicability. RESULTS. System S 4000: Because of the older system architecture, the response time to key inputs was fairly long and the menu structure somewhat uncomfortable. A major drawback was the limited data buffer capacity and the lack of a long-term storage medium as well as the lack of compatibility with the industry standard for PCs. Software interfaces to other companies' monitors were not implemented, limiting the system to the Sirecust 404 devices. Patient-Care-Manager: The user interface is a Windows 3.0 application representing an up-to-date graphical environment. Unfortunately some Windows features were not fully used, e.g. the free positioning and sizing of graphic windows and the color options. Drug inputs were somewhat long-winded, limiting the system's suitability for the operating theatre. The main disadvantage, however, was the lack of interfaces to monitors other than those from Siemens. Monitor Data Manager: The system was designed to sample data from all monitors operating in our hospital's heart surgery department. Each parameter was displayed in a digital form to get close control over the recorded data (Fig. 1b); additionally calculated values like total peripheral resistance or oxygen demand could be drawn from a separate window. Furthermore, key inputs were reduced to minimum, making drug inputs faster than the hand-written protocol. The ease of performing calculations of continuous drug infusions (from microgram/kg/min to ml/h pump speed) was particularly appreciated by the users. Since the data were saved as an ASCII file, they could easily be imported by any spreadsheet like Lotus 1-2-3 or Excel, providing the whole variety of their graphical presentation or calculation features. Because of the high sampling rate (3 min), even short-lasting drug effects could be registered, making the system favourable for scientific studies. CONCLUSION. Automated monitor data record systems are considered to be a prerequisite not only for research in anaesthesia but also for quality assurance. A basic requirement for wide acceptance in clinical practice is a user interface that provides fast and convenient key inputs as well as further information about parameters not displayed on other monitors. In our h

Anesthesia↗
PubMed1993

[Radiologic position control of epidural catheters (epidurography). An instrument of quality assurance for regional analgesia].

Epidural analgesia is a very efficient method of postoperative pain management. Nevertheless, problems such as unilateral analgesia, sensory loss and inadequate pain relief are often difficult to handle. Radiologic evaluation of the position of the catheter and the spread of radiopaque dye (epidurography) is an important advance toward a solution of these problems. METHODS. The findings of 110 consecutive epidurographies from the acute pain service of the Department of Anaesthesiology of the University Hospital of Kiel, Germany, were analysed. Radiograms were obtained following the injection of 2 ml and an additional 8 ml of radiopaque dye (iopamidol) in the anterior-posterior and lateral plane. In addition, typical and instructive examples of epidurographies from the past 8 years are presented. RESULTS. In 99 of 110 patients the epidurography revealed a proper position of the catheter. Seven cases of partial displacement (e.g. paravertebral spread of radiopaque dye) and two cases of complete misplacement were documented. Allergic reactions or other side effects were not observed. The radiologic criteria for a proper epidural position of the catheter are discussed (Fig. 2a). Furthermore, examples of the following malpositions of epidural catheters are presented: intravascular misplacement (Fig. 2b), paravertebral misplacement (Fig. 2c), paravertebral escape of radiopaque dye (Fig. 2e) and correct distribution after the catheter had been withdrawn 2 cm (Fig. 2f), intrathecal misplacement (Fig. 2g), and simultaneous spread of dye in the subarachnoid and epidural space in a patient with preceding dural tap (Fig. 2h). In some cases unexpected reasons for problems in postoperative pain management were revealed by epidurography (e.g. disc prolapse, (Fig. 2d). CONCLUSION. In our view epidurography is a valuable way of improving the quality and safety of postoperative epidural analgesia. It is an important tool for decision-making in the event of clinical problems. The benefits for the patients have to be weighed against the radiation exposure.

Aged↗
PubMed1992

[Nifedipine versus nitroglycerin in aortocoronary bypass surgery. The effect on hemodynamics, kidney function and homologous blood requirement].

Even during adequate general anesthesia, hypertension is a common phenomenon in patients undergoing aortocoronary bypass grafting (CABG). In such cases application of vasodilators is recommended in order to decrease myocardial oxygen consumption. This study was performed to compare two commonly used substances, i.e., nitrates and nifedipine, with regard to their influence on hemodynamics, renal blood flow, kidney function, and the requirement for homologous blood transfusions. METHODS. Forty-four patients gave their informed consent to the study. They were randomly divided into 2 groups: group 1 received nitroglycerin (3.0 micrograms/kg.min), group 2 nifedipine (Adalat, 0.5 microgram/kg.min) in order to prevent hypertension in the phase before onset of cardiopulmonary bypass (CPB). Anesthesia was induced by etomidate and succinylcholine and maintained as a modified neuroleptanalgesia with fentanyl (up to 50 micrograms/kg), midazolam (0.3 mg/kg.h), and pancuronium (0.1 mg/kg). Systolic blood pressure was kept within the range of 120-160 mm Hg; in case of higher values boluses of either 0.25 mg nitroglycerin or 0.5 mg nifedipine were administered. Cardiac index, stroke volume index, rate-pressure product, intrapulmonary shunt, and pulmonary and total peripheral resistances were evaluated at five predefined points: (1) after induction of anesthesia; (2) before incision; (3) before cannulating the aorta; (4) after decannulating the aorta; and (5) at the end of operation. Creatinine and free-water clearances as well as sodium and potassium excretion were calculated for three phases of the operation: (A) induction of anesthesia--onset of CPB; (B) during CPB; and (C) end of CPB--end of operation. CPB was performed using a membrane oxygenator (Sorin 51) and a nonpulsatile blood flow of 2.5 1/min.m2, which was reduced during mild hypothermia of 30-32 degrees C to 1.7 l/min.m2. Mean arterial pressure in both groups was kept at approximately 70 mm Hg. In case of lower pressures norepinephrine (50-100 micrograms/bolus) was administered; higher pressures were treated as described above. Volume substitution was performed initially by 500 ml hydroxyethyl starch and continued, if necessary, by homologous blood or 5% human albumin in order to keep the hematocrit greater than 30 in the phases before and after CPB. RESULTS. Group 2 showed significantly higher values of cardiac index and stroke volume index at point 3 while the rate-pressure product was clearly lower, indicating better myocardial performance and lower oxygen consumption than in group 1. Creatinine and free-water clearances in all three phases did not differ. However, sodium excretion during CPB was significantly higher in the nifedipine group while potassium excretion showed no differences. The average requirement for blood and blood substitutes was lower in group 2, but the difference could not be confirmed statistically because of the large dispersion of values. Nevertheless, 4 patients in the nifedipine group but no patient in group 1 did not need homologous blood transfusion. CONCLUSION. In comparison to nitrates, nifedipine showed some advantages in the treatment of hypertension during CABG: (1) it provided better myocardial performance; (2) it had a more reliable but not too long-lasting effect on elevated total peripherial resistance, leading to better hemodynamic stability; and (3) by not affecting the capacitance vessels it may necessitate fewer homologous blood transfusions.

Adult↗
PubMed1992

[Complications and side effects of stellate ganglion blockade. Results of a questionnaire survey].

Stellate ganglion blockade (SGB) is an established method in the therapy of chronic pain syndromes. Complications are rare but can be life-threatening (inadvertant subarachnoid or intra-arterial injection). Since no data are currently available as to the incidence of complications, we sent questionnaires to 76 departments of anaesthesiology in West Germany to evaluate this issue. RESULTS. Thirty-nine questionnaires (51%) were returned, representing approximately 45,000 SGBs; 82% of the departments prefer bupivacaine for SGB. The incidence of severe complications was 1.7 in 1000 blockades. Most of these were CNS complications (i.e., convulsions). A high subarachnoid block was reported in 6 cases, high epidural blockade in 3, pneumothorax in 9, and allergic reactions in 2. All departments conduct aspiration tests before injection; 94% take precautionary measures in case of respiratory failure (oxygen, ventilating devices); 73% do not perform SGB without an assistant and an anticonvulsant drug at hand; 72% place an intravenous line before SGB; 28% use ECG monitoring routinely; and 53% administer a test dose of 0.5-2 ml local anaesthetic. DISCUSSION. Severe complications following SGB are rare. Potentially life-threatening complications usually arise from inadvertant subarachnoid or intra-arterial injection. Aspiration tests and test doses obviously do not guarantee proper administration. Placement of an intravenous line, ECG monitoring, and the presence of an assistant are strongly recommended. Anticonvulsant drugs as well as drugs and equipment for intubation and resuscitation should be immediately available. The administration of very low doses of opioids to the stellate ganglion has been shown to have similar therapeutic results to local anaesthetic blocks, whereas the incidence of side effects and complications is lower. Therefore, the administration of opioids to sympathetic ganglia could provide an alternative therapeutic regimen for the future.

Adult↗
PubMed1991

Plasma protein binding of bupivacaine in pregnant women at term.

The increased toxicity of bupivacaine in parturients is a well-known phenomenon. The reduced plasma protein binding of bupivacaine is one of the possible reasons. Therefore, we measured the free fraction of bupivacaine in plasma samples of parturients and non-pregnant volunteers. The free fraction was significantly higher in parturients (8.2% vs 5.4%) associated with a lower concentration of the alpha-1-acid glycoprotein (0.42 vs 1.01 g/l) and a higher concentration of progesterone (156 vs 0.4 ng/ml). The addition of progesterone to plasma samples of non-pregnant volunteers did not influence the free fraction of bupivacaine, whereas the addition of alpha-1-acid glycoprotein to the plasma of parturients decreased the free fraction significantly. Therefore, the lower concentration of this protein is the principal reason for the higher free fraction of bupivacaine in pregnancy and possibly one of the causes of the higher incidence of toxic side effects of bupivacaine in obstetric use.

Adolescent↗
PubMed1991

[The treatment of zoster neuralgia].

Neuralgic pain during or following herpes zoster infection is a common problem in pain therapy. The current management of neuralgias due to zoster is discussed with reference to patients in a chronic pain clinic within an anesthesiology department. The courses of 80 patients followed up for at least 3 months from the pain clinic at the University Hospital in Kiel were analyzed. The mean age was 69 years. The predominant locations for zoster lesions were the thoracic segments (65%) and the first branch of the trigeminal nerve (19%). Diabetes mellitus was present in 20% of the patients and malignant disease in 18%. In 2 patients recurrent postherpetic neuralgia was the first symptom of HIV infection. Despite pretreatment, the mean initial pain score was 8 on an analog scale (range 0-10). Acute herpes zoster pain during the infection was treated with virustatic agents, corticosteroids and sympathetic blocks. Postherpetic neuralgias required a more sophisticated approach, depending on the stage of the disease and the type of pain involved: sympathetic blockade with local anesthetic agents or injections of very low dose opioids to sympathetic ganglia, transcutaneous electrical nerve stimulation, and antidepressants or anticonvulsants. The success of the therapy is correlated with the duration of pain. If the history of zoster pain was less than 1 month, the majority of patients showed good or excellent results. On the other hand, only one-third of patients with a history longer than 6 months had adequate pain relief. Therefore, early and appropriate treatment is desirable for patients suffering from zoster neuralgias.

Aged↗
PubMed1991

[Clinical pharmacokinetics of lidocaine after intraoral nerve block].

Aim of this study was to show the time course of plasma concentrations of 2% lignocaine with adrenalin at a concentration of 1:100,000. Four retinated third molars were removed in one session in 23 patients. For local anaesthesia in each patient we used 10 ml of Xylocaine 2% (Astra), which is commonly used in dentistry. The plasma-concentration was measured for the first 30 minutes after injection of the local anaesthetic using high pressure liquid chromatography (HPLC). Our results suggest that partially intravascular injection could not be avoided although careful aspiration was carried out before injecting. Neither subjective nor objective adverse central nervous effects were seen in our patients. Nevertheless we consider a peripheral intravenous cannula and ECG-monitoring strongly recommended in all major operations under local anaesthesia.

Adolescent↗
PubMed1991

[Results of a questionnaire survey of the practice and organization of postoperative peridural analgesia at 461 anesthesia departments].

In 1988, questionnaires were sent to 1225 departments of anesthesiology to evaluate the practice of postoperative epidural analgesia (EA) in the Federal Republic of Germany. The following problems were investigated. To what extent are anesthesiologists concerned with postoperative pain therapy? Does EA play a major role in this, in particular outside the intensive care setting? Who is allowed to administer epidural injections: anesthesiologists, other physicians or nurses? What kind of monitoring is used? What agents are used for epidural injections and what problems and complications have arisen? In all, 461 (38%) evaluable forms were returned. Most anesthesiologists said they were responsible for postoperative pain control. In 75.3% of the responding departments EA was used as a method of postoperative pain therapy, while in 24.7% the catheter was removed immediately after the operation, in most cases for fear of complications resulting from insufficient monitoring. In clinical practice, however, EA was the only major alternative to routine intermittent injections of opioids as needed. Some departments reported that they restricted postoperative EA to patients in the intensive care unit or in the recovery room because adequate monitoring was not feasible on the ordinary wards. EA was administered in 62.4% on ordinary wards. But in only 25.7% were trained nurses allowed to give epidural injections. Most responding departments (77%) preferred epidural use of opioids during intensive care, in most cases morphine or buprenorphine in combination with low-dose local anesthetics, and 66.7% also favored epidural opioids on ordinary wards.

Analgesia, Epidural↗
PubMed1991

[Intrapleural catheter analgesia in patients with multiple rib fractures].

Patients with multiple rib fractures often suffer from severe pain that impairs their respiratory performance. The effect of interpleural administration of bupivacaine (20 ml 0.25% every 4 h) for pain management was evaluated in ten patients. The initial interpleural injection resulted in significant pain relief and improvement of arterial oxygen tension. Two patients needed additional i.v. injections of opioids (piritramide 15-22.5 mg/24 h). In one patient a small asymptomatic pneumothorax was observed following placement of the catheter, which resolved spontaneously. No other complications were reported. In an intraindividual comparison, bupivacaine alone and bupivacaine plus epinephrine 1:200,000 were compared with regard to pharmacokinetics of bupivacaine, analgesic effect, side effects, and respiratory performance. The addition of epinephrine yielded only minor advantages from a pharmacokinetic point of view (median peak concentration of bupivacaine 1.8 micrograms/ml vs 2.0 micrograms/ml for bupivacaine alone). The quality and duration of analgesia and the effects on respiration were not influenced by epinephrine. The heart rate was significantly higher and the blood pressure significantly lower when epinephrine was added to the solution. Nevertheless, these differences were too small to be of clinical importance. Even though maximum total plasma concentrations of bupivacaine above 2 micrograms/ml were found in some patients, there were no signs of CNS toxicity, most probably because of the increased protein binding of bupivacaine following trauma. Accordingly, the maximum free plasma concentrations in all patients were below the threshold level of 0.24 micron/ml. We therefore conclude tht interpleural administration of bupivacaine could be a valuable means of pain relief in patients with multiple rib fractures, providing no severe pulmonary contusions or concomitant injuries are present.

Adult↗