Biomedical subjects

P Lipfert

Publications and source records attributed to P Lipfert.

At least 19 recordsLinked to original sources

PubMed2006

Sedation during spinal anaesthesia in infants.

BACKGROUND: Neuraxial anaesthesia in adults decreases the dose of i.v. or inhalational anaesthetic needed to reach a desired level of sedation. Furthermore, spinal anaesthesia alone has a sedative effect. The mechanism behind this phenomenon is presumed to be decreased afferent stimulation of the reticular activating system after sympatholysis. We hypothesized that this mechanism is equally active in infants undergoing spinal anaesthesia. METHODS: In total, 20 unpremedicated former preterm infants underwent surgery under spinal anaesthesia with hyperbaric bupivacaine 0.5% 1 mg kg(-1) with epinephrine 10 microg kg(-1). No additional sedatives or anaesthetics were administered. Sedation was evaluated using the bispectral index (BIS) score and the 95% spectral edge frequency (SEF(95)). RESULTS: After spinal anaesthesia, mean (SD) BIS began to decrease significantly from baseline 97.0 (1.1) to 83.9 (14.4) after 15 min (P=0.006). BIS decreased further, reaching the lowest values after 30 min [62.2 (14.0); P<0.00001]. Mean (SD) SEF(95) declined from baseline 26.1 (1.8) Hz to 24.3 (3.1) after 5 min (P=0.02) and further to 9.9 (3.8) after 30 min (P<0.00001). Mean arterial pressure also decreased significantly from 66.5 (4.7) mm Hg within 10 min to 56.1 (5.6) after spinal anaesthesia (P=0.0002), while heart rate remained stable. CONCLUSIONS: These results suggest that sedation after spinal anaesthesia in infants is at least as pronounced as in adults. The sedative effect of spinal anaesthesia should be kept in mind when additional sedatives are administered, especially in former preterm infants.

Anesthesia, Spinal↗

PubMed2006

[Intraoperative and postoperative analgesia with a caudal catheter in a child suffering from Schwartz-Jampel syndrome].

The Schwartz-Jampel syndrome, also known as myotonia chondrodystrophica, is a rare autosomal recessive disorder characterized by bone dysplasia, growth retardation and generalized myotonia. Laryngoscopy and intubation may be difficult because of micrognathia and limited mouth opening due to myotonia of the masseter muscles. As regional anaesthesia reduces myotonic contractions and avoids administration of opioids causing respiratory depression, it appears to be the ideal method for postoperative analgesia. We report on a 5-year-old girl who underwent osteotomy of both hips and received intraoperative and postoperative analgesia via a caudal catheter. Excellent analgesia without myoclonic episodes could be achieved by continuous infusion of ropivacaine.

Amides↗

PubMed2006

Propofol infusion syndrome during anaesthesia for scoliosis surgery in an adolescent with neonatal progeroid syndrome.

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Acidosis↗

PubMed2006

The effect of mirtazapine in patients with chronic pain and concomitant depression.

OBJECTIVE: To evaluate the safety, tolerability and efficacy of mirtazapine in patients with the primary diagnosis of chronic pain and concomitant depression in an open post-marketing surveillance study. RESEARCH DESIGN AND METHODS: 594 patients with a primary diagnosis of at least one chronic pain syndrome (minimum duration of 3 months) and the diagnosis of concomitant depression, appropriately made by a neurologist or psychiatrist, were recruited at psychiatric and/or neurological outpatient facilities throughout Germany. The primary efficacy parameter was pain at baseline and endpoint using a patient self-assessment scale. Secondary analyses were performed at baseline, week 1 (day 7 +/- 2), week 4 (day 28 +/- 4) and at endpoint (day 42 +/- 4 or early termination) and included safety and tolerability assessments. Investigators rated the severity of different potential co-morbidities (including depression) with a four-step rating scale (not present, mild, moderate, severe). RESULTS: 594 patients were enrolled and treated with mirtazapine (mean daily dose of 34.5 +/- 10.4 mg at study endpoint). A statistically significant (p < 0.0001; one sample sign test) reduction of pain from baseline to endpoint was found for the overall population. The percentage of patients free of pain or with only moderate pain increased significantly, irrespective of patients' age or pain syndromes. Furthermore, we found a substantial improvement from baseline to endpoint regarding co-morbidities such as sleep disturbance, irritability and exhaustion. The number of adverse events was low (<7%; n = 37), with fatigue (n = 13) and weight gain (n = 11) occurring most frequently. No previously-unknown side effects occurred. One hundred and six patients (18%) discontinued mirtazapine during the study. The main reason was lack of efficacy (6%, n = 33), which may be a reflection of sub-optimal response to the anti-depressant or analgesic effect of the drug, but no appropriate rating scale was used to clarify this question. Only a small number of patients stopped the drug due to adverse events (3%; n = 15). At study endpoint, the majority of physicians and patients rated the overall efficacy and tolerability of mirtazapine as good or very good. Most patients (80%) continued the therapy after 6 weeks. CONCLUSIONS: Despite the limitations of an open observational study, our findings suggest that mirtazapine is a safe and well-tolerated drug for use in daily clinical practice. It still remains unclear whether the reduction of pain, the enhancement of the depressed mood or the combination of both effects led to these results. Nevertheless, our data point to a potential beneficial effect of mirtazapine in the treatment of patients with pain and concomitant depression. However, more systematic research, including placebo-controlled studies, and further empirical testing are necessary.

Adolescent↗

PubMed2004

Tetrodotoxin-induced conduction blockade is prolonged by hyaluronic acid with and without bupivacaine.

BACKGROUND: In isolated nerves, tetrodotoxin (TTX) blocks nerve conduction longer than bupivacaine. In vivo, however, both substances block nerve conduction to an equal duration, presumably because the hydrophilic TTX binds only weakly to the perineural tissue. High molecular weight hyaluronic acid (HA) prolongs the action of local anaesthetics several-fold. We tested whether admixture of HA enhances the binding of TTX to the perineural tissue and thus induces an ultra-long conduction block after a single application. METHODS: In 12 anaesthetized rabbits, the minimal blocking concentrations of TTX, TTX and HA (TTX/HA) and bupivacaine with HA (bupivacaine/HA) were determined by blocking the natural spike activity of the aortic nerve. In 18 other animals, equipotent concentrations of either TTX, TTX/HA or TTX/bupivacaine/HA were applied topically to the aortic nerve. After disappearance of the spike activity, the wound was closed to simulate the clinical situation of a single shot nerve block. The time until recovery of spike activity was determined. The nerves were examined for signs of neurotoxicity 24 h after the application of the drugs. Data are presented as means +/- SD and compared by ANOVA and Student's t-test for unpaired data. RESULTS: The conduction block by TTX/bupivacaine/HA (10.1 +/- 1.9 h) or TTX/HA (9.3 +/- 1.0 h) was significantly longer than that of plain TTX (7.9 +/- 1.0 h). Neurotoxicity was not observed. CONCLUSIONS: Both HA and HA/bupivacaine prolong the TTX-induced conduction blockade of the aortic nerve of rabbits in vivo. No signs of neurotoxicity were observed.

Anesthetics, Local↗

PubMed2004

Tetrodotoxin-induced conduction blockade is prolonged by hyaluronic acid with and without bupivacaine.

Anesthetics, Local↗

PubMed2001

Lidocaine reduces ischaemic but not reperfusion injury in isolated rat heart.

The local anaesthetic lidocaine protects the myocardium in ischaemia-reperfusion situations. It is not known if this is the consequence of an anti-ischaemic effect or an effect on reperfusion injury. Therefore, we investigated the effect of two concentrations of lidocaine on myocardial ischaemia-reperfusion injury and on reperfusion injury alone. We used an isolated rat heart model where heart rate, ventricular volume and coronary flow were kept constant. Hearts underwent 45 min of low-flow ischaemia followed by 90 min reperfusion. Two groups received lidocaine 1.7 or 17 microg ml(-1) starting 5 min before the onset of reperfusion. In two additional groups, lidocaine infusion started 5 min before low-flow ischaemia. In all groups, lidocaine administration was stopped after 15 min of reperfusion. One group served as an untreated control (n=11 in each group). Left ventricular developed pressure (LVDP) and total creatine kinase release (CKR) were measured. Lidocaine administration during ischaemia and reperfusion led to an improved recovery of LVDP during reperfusion (1.7 microg ml(-1), 54 (SEM 10) mm Hg; 17 microg ml(-1), 71 (9) mm Hg at 30 min of reperfusion; both significantly different from control (21 (4) mm Hg) (P<0.05)) and a reduced CKR (1.7 microg ml(-1), 79 (13) IU; 17 microg ml(-1), 52 (8) IU at 30 min of reperfusion; both significantly different from control (130 (8) IU (P<0.05)). Lidocaine given during early reperfusion only, affected neither LVDP during reperfusion (1.7 microg ml(-1), 19 (6) mm Hg (P=1.0); 17 microg ml(-1), 36 (8) mm Hg (P=0.46)) nor CKR (156 (21) IU (P=0.50) and 106 (14) IU (P=0.57)). We conclude that lidocaine protects the myocardium against ischaemic but not against reperfusion injury in the isolated rat heart.

Analysis of Variance↗

PubMed1998

Inactivation of baroafferents leads to loss of barosensitivity without changes in nerve morphology.

Baroreceptors are stretch-sensitive mechanoreceptors, which are silenced by preventing distension of the receptor zone. Does chronic inactivation of these peripheral afferents alter their function or morphology? Compound action potentials and morphometry of carotid sinus nerves of 10 rabbits were investigated. The baroafferents were inactivated by embedding the pressure-released carotid sinus into silicon gel. The success of this procedure was validated by the absence of spike activity of the sinus nerve during normal and elevated systemic blood pressure. The contralateral vessels of the same animals were sham-operated and also embedded into silicon, but without prevention of wall movements. After 5, 7, 14 or 28 days the nerves were functionally reinvestigated before and after release of the sinus wall. Afterwards, the morphology of the nerve cross-sections was analysed by morphometry of electron micrographs. Baroafferents did not regain spike activity during immobilisation of the sinus wall. After release of the carotid sinus wall only nerves inactivated for five days regained their pulse synchronous baroreceptor discharge. Following seven days of inactivation, baroreceptor discharge could be elicited by maximal pressure elevation in only one of three nerves. At any time later, the baroreceptor response to arterial pressure changes was lost completely. The activity of the control nerves was preserved after 28 days. No obvious differences in fibre size and myelin thickness were observed between inactivated and control nerves. Inactivation of baroafferents for more than one week leads to a loss of pressure-dependent spike activity. Since morphology did not differ between inactivated and control nerves, it is suggested that changes of baroreceptor endings are responsible for this loss of function.

Action Potentials↗

PubMed1997

[Ipsilateral pneumothorax in one-lung respiration. A rare, recently diagnosed and atypical complication of a double lumen tube].

The authors report a rare, recently diagnosed and atypical mishap during one-lung ventilation (OLV) via a double lumen tube (DLT) and left-sided thoracotomy: an ipsilateral pneumothorax during ventilation of the right lung. This occurred in a 63-year-old patient with chronic obstructive airway disease who was scheduled for urgent repair of a descending thoracic aortic aneurysm. Anaesthesia and surgery were uneventful until aortic cross-clamping release. The common presentation of increased intrathoracic extrapleural pressure owing to a pneumothorax in patients with mechanically ventilated lungs is a rapid decrease in oxygen saturation, followed or paralleled by haemodynamic deterioration. Although the above presentation could be seen in this case, the diagnosis of a tension pneumothorax was delayed twice. First, symptoms were initially obscured by haemodynamic changes resulting from a head-down tilt and aortic declamping. Second, since the lack of consolidation after aortic declamping focused attention on the airway problems, complications resulting from the use of a DLT were primarily considered. In particular, since breathing sounds were detectable initially, malposition or torsion of the DLT had to be excluded by fibre-optic bronchoscopy, which involved a further delay. Finally, two observations led to the diagnosis of a right-sided tension pneumothorax: (1) bullae of the contralateral lung, detected during thoracotomy; (2) the finding that ventilation of both lungs and the left lung subsequently increased arterial (SaO2) and mixed venous oxygen saturation (SvO2) and the circulatory status, but ventilation of the right lung caused a deterioration. Chest radiography and insertion of a chest tube with drainage of air, thereafter, validated our hypothesis. The time course of oxygen desaturation during OLV and tension pneumothorax was as severe as expected; the time course of haemodynamic deterioration, however, appeared quicker and had more impact than expected. Assuming that mediastinal deviation was not hindered by contralateral intrathoracic pressure during thoracotomy, we believed that circulation should be depressed later or to a lesser extent in patients with an intraoperative pneumothorax. Yet, during thoracotomy, decrease in cardiac filling and output during tension pneumothorax in OLV obviously results primarily from the immovability of the mediastinum owing to mediastinal fixation and is at least as decisive as the contralateral intrathoracic pressure in closed-chest patients. In summary, a tension pneumothorax during one-lung ventilation and thoracotomy is a rare, but disastrous complication during the use of a DLT, which has not, to our knowledge, been reported previously. We recommend that tension pneumothorax be added to the list of complications and problems during OLV by the use of a DLT, especially in patients with structural lung diseases.

Anesthesia↗

PubMed1997

[Chronopharmacology. Time of day variations in the action of bupivacaine are not manifested in nerves].

UNLABELLED: To test the hypothesis that the efficacy of local anaesthetics to block nerve conduction is related the time of day (TOD) of drug application, we retrospectively analysed data from previous experiments on tachyphylaxis. During the course of these experiments, as a measure of drug efficacy we determined the minimal blocking concentration (c(m)) of bupivacaine in rabbit aortic nerves at several TODs. The special in situ preparation used permitted study of local anaesthetic pharmacodynamics without the influence of pharmacokinetics, making it possible to investigate the chronopharmacodynamics of these drugs by relating c(m)s to the respective TODs of their measurement. METHODS: In 43 New Zealand rabbits anaesthetised with urethane, the aortic nerve was dissected and partly placed in a double-lumen perfusion chamber (Fig. 1A), which was continuously perfused with tyrode solution or bupivacaine. Spike activity was continuously recorded by bipolar platinum-iridium electrodes caudad to the chamber for control and cephalad for registration of blocking effects. As a measure of drug efficacy, by increasing the bupivacaine concentration stepwise we determined the smallest concentration that blocks spike activity i.e., c(m). After each determination bupivacaine was rinsed off to confirm intact nerve function (Fig. 18). RESULTS: Forty-nine determinations of bupivacaine c(m) were performed between 12:25 p.m. and 2:35 a.m. Data were pooled into groups of 2 h (Fig. 2). There was no significant difference between groups (ANOVA). In particular, c(m) at 3:00 p.m. was not lower than at 11:00 p.m., times at which local anaesthetics have been found to be most and least effective, respectively. CONCLUSIONS: The c(m) of bupivacaine, and thus its efficacy to block nerve conduction, does not depend on TOD of drug application. Therefore, it is suggested that chronopharmacodynamics does not play an important role in the well-known circadian rhythm of the action of bupivacaine and probably of local anaesthetics in general.

Anesthetics, Local↗

PubMed1996

[Conduction block in man is stimulation frequency dependent].

The action of local anaesthetics on isolated nerves is enhanced by high stimulation frequencies. The aim of our study was to investigate whether high-frequency stimulation enhances regional anaesthesia in man. METHODS. Seven healthy volunteers underwent three ulnar nerve blocks while non-noxious electrical stimulation with high (10, 50 Hz) or low (0.2 Hz) frequencies was applied via a widespread cutaneous electrode in the area supplied by the ulnar nerve. Perception was monitored continuously by means of a visual analogue scale. Skin temperature (infrared telethermometry) was evaluated every minute as an indicator of vasomotor block. After complete loss of perception or after 45 min, the spread of anaesthesia was determined by sharp-dull discrimination. The nerve block was preceded by a control stimulation of 45 min under otherwise identical conditions. RESULTS. During stimulation with 10 and 50 Hz, perception was lost significantly earlier than with 0.2 Hz. The spread of sensory block at the end of the experiments was also enhanced by stimulation with high frequencies, whereas the onset of vasomotor block (rise in skin temperature) remained unaltered. CONCLUSION. Non-oxious electrical stimulation with high frequencies significantly accelerates the onset of anaesthesia and extends the spread of sensory block.

Adult↗

PubMed1996

Intravenous lidocaine and bupivacaine dose-dependently attenuate bronchial hyperreactivity in awake volunteers.

BACKGROUND: In standard textbooks, intravenous lidocaine is recommended for intubation of patients with bronchial hyperreactivity. However, whether and to what extent intravenous local anesthetics attenuate bronchial hyperreactivity in humans is unknown. Accordingly, nine awake volunteers with known bronchial hyperreactivity were subjected to an inhalational challenge with acetylcholine before and during intravenous infusion of lidocaine, bupivacaine, or placebo in a randomized, double-blinded fashion. METHODS: Baseline acetylcholine threshold concentrations were determined 3-5 days before initiation of the investigation. The response to the acetylcholine challenge was defined as hyperreactive, if forced expiratory volume in 1 s decreased by at least 20%. In addition, the acetylcholine threshold for a 100% increase in airway resistance was obtained by body plethysmography. On seven different days, the acetylcholine challenge was repeated at the end of a 30-min intravenous infusion period of three doses of lidocaine (1, 3, and 6 mg.min(-1)) or bupivacaine (0.25, 0.75, and 1.5 mg.min(-1)), during saline placebo infusion, respectively. Acetylcholine-threshold concentrations were presented with the respective plasma concentrations of the local anesthetic. RESULTS: The infusion of lidocaine and bupivacaine resulted in plasma concentrations (means +/- SD) of 0.29 +/- 0.11, 1.14 +/- 0.39, and 2.02 +/- 0.5 microg.ml(-1) for lidocaine and 0.11 +/- 0.04, 0.31 +/- 0.09, and 0.80 +/- 0.18 microg.ml(-1) for bupivacaine, respectively. Compared to baseline, the acetylcholine threshold for a 20% decrease of forced expiratory volume in 1 s as well as the threshold for a 100% increase in total airway resistance increased significantly with increasing plasma concentrations of both local anesthetics. Compared to placebo, acetylcholine threshold was almost quadrupled for lidocaine and tripled for bupivacaine with the highest plasma concentration of each local anesthetic. CONCLUSIONS: In awake humans, intravenous lidocaine and bupivacaine both dose-dependently attenuated the hyperreactive response to a nonspecific inhalational challenge with acetylcholine.

Adult↗

PubMed1996

Effect of transcutaneous electrical nerve stimulation on onset of axillary plexus block.

We examined the effect of high frequency transcutaneous electrical nerve stimulation on the onset of brachial plexus block. Three groups of patients scheduled for surgery of the hand had a local anaesthetic block performed with 40 ml mepivacaine 1.5% using the axillary approach. After injection of the local anaesthetic transcutaneous electrical nerve stimulation was applied for 15 min either to the median nerve or the ulnar nerve; no stimulation was applied in the control group. Before and for 45 min after, the injection of local anaesthetic touch perception, pin prick, motor strength and skin temperature were tested by a blinded investigator in the areas supplied by the median, musculocutaneous, radial and ulnar nerves. There were no differences in the onset of block between the groups. Thus, the frequency-dependent action of local anaesthetics could not be demonstrated.

Adult↗

PubMed1995

Pulmonary sympathetic denervation does not increase airway resistance in patients with chronic obstructive pulmonary disease (COPD).

Whether or not neural blockade of pulmonary sympathetic innervation is of relevance for airway resistance in patients with chronic obstructive pulmonary disease (COPD) is unknown. Accordingly we evaluated airway resistance during sympathetic blockade by high thoracic epidural anaesthesia in patients with COPD. Before and 45 min after thoracic epidural injection of bupivacaine 0.75% (6-8 ml; n = 10) total respiratory resistance (oscillometry, ROS), vital capacity (VC), forced expiratory vital capacity in 1 s (FEV1, [%VC]), functional residual capacity (FRC; helium dilution method), and arterial blood gases were measured. Three additional patients received bupivacaine intravenously (1.2 mg.min-1 for 45 min), another three received saline epidurally. Sensory blockade covered segment C5 through T8. As an indicator of widespread sympathetic blockade including the lungs, skin temperature increased significantly on thumb and little toe. Despite pulmonary sympathetic denervation ROS, FEV1, and FRC remained unchanged, while VC decreased slightly, probably due to intercostal muscle blockade. Blood gases remained constant. Neither intravenous bupivacaine nor epidural saline evoked directional changes. Since, in contrast to beta-adrenoceptor blockade, pulmonary sympathetic denervation did not increase airway resistance in patients with COPD, neural sympathetic blockade seems to be of no relevance for airway resistance in these patients.

Airway Resistance↗

PubMed1994

Pre-emptive analgesia: comparison of preoperative with postoperative caudal block on postoperative pain in children.

We have compared in 25 children the effect of preoperative with postoperative caudal block on pain after circumcision in a double-blind, randomized study. After induction of anaesthesia, patients were allocated randomly to receive a caudal block either before (n = 14) or immediately after (n = 11) surgery. Postoperative pain was rated on a paediatric pain scale. If pain occurred, children received paracetamol in a dose related to body weight. Using the Mann-Whitney U test (significance < or = 0.05) there was no significant difference in cumulative postoperative analgesic requirements within the first 48 h and in times to first analgesic administration between the groups. Cumulative pain score, assessed every 30 min for the first 8 h after operation, was significantly lower for those patients who received caudal anaesthesia after operation. Thus we could not demonstrate any advantage in performing caudal block before compared with after surgery.

Acetaminophen↗

PubMed1994

High thoracic epidural anesthesia does not alter airway resistance and attenuates the response to an inhalational provocation test in patients with bronchial hyperreactivity.

BACKGROUND: The functional relevance of an intact pulmonary sympathetic innervation for airway resistance is unknown. We therefore evaluated whether or not pulmonary sympathetic denervation by thoracic epidural anesthesia decreases the threshold of an inhalational provocation with acetylcholine in 20 patients with documented bronchial hyperreactivity scheduled for elective upper abdominal or thoracic surgery. METHODS: Baseline inhalational provocation with acetylcholine was performed 2-4 days before surgery. The acetylcholine threshold concentration for a hyperreactivity response (i.e., for a 20% decrease in forced expiratory volume in 1 s and a 100% increase in total respiratory resistance by oscillometry) was determined. On the day of surgery a second inhalative provocation with acetylcholine was performed 45 min after the patients had received 6-8 ml epidural bupivacaine 0.75% (n = 10), intravenous bupivacaine (1.2 mg.min-1, n = 6), or 6-8 ml epidural saline (n = 4). The acetylcholine threshold concentration for a hyperreactive response was again determined. We also measured vital capacity, forced expiratory volume in 1 s as a percentage of vital capacity, spread of sensory blockade (pin prick), skin temperature on hand and foot (telethermography). RESULTS: During thoracic epidural anesthesia, C4-T8 skin temperature increased significantly on hand and foot indicating widespread sympathetic blockade including the lungs. Compared to values obtained immediately before pulmonary sympathetic blockade, forced expiratory volume in 1 s as a percentage of vital capacity, and total respiratory resistance by oscillometry remained unchanged, while vital capacity decreased. Compared to baseline the acetylcholine threshold concentration for the hyperreactive response increased threefold after epidural as well as after intravenous bupivacaine. Epidural saline evoked no directional changes in the acetylcholine threshold concentration. CONCLUSIONS: We conclude that in patients with bronchial hyperreactivity 1. blockade of pulmonary sympathetic innervation seems to be of no relevance for airway resistance and 2. both epidural and intravenous bupivacaine substantially attenuate the response to an inhalational provocation with acetylcholine.

Acetylcholine↗

PubMed1993

In vivo determination of concentration-effect curves of local anaesthetics in man.

In clinical use, the concentrations of local anaesthetics at the site of action are unknown. With the method described here, concentrations of local anaesthetics can be predetermined and kept constant at the site of action. In six volunteers, a blister was raised on the ventral surface of the forearm. After removal of the epithelium, the blister base was rinsed continuously with carbogenated Tyrode's solution with and without increasing concentrations of bupivacaine (Carbostesin) for 15 min each. The effects of bupivacaine were determined by changes in the perception (tactile sensation) of drops falling on the blister base from increasing heights. The minimal height at which the drops were just perceived characterized the threshold of perception. With increasing bupivacaine concentrations, threshold increased until the drops were no longer perceived, at a median concentration of 2.48 mmol litre-1 (range 1.24-3.10 mmol litre-1). After the blister base was rinsed with Tyrode's solution, threshold of perception reached baseline values, which was in accordance with an intact blister base.

Adult↗

PubMed1993

Dermal anaesthesia: comparison of EMLA cream with iontophoretic local anaesthesia.

We have compared the efficacy of two non-invasive methods of transdermal anaesthesia: application of EMLA cream and iontophoresis of 5% lignocaine with adrenaline 1:50,000 in six healthy subjects. We tested depth of tissue penetration (pinprick) and effect on pain evoked by i.v. injection. After iontophoresis, pain on i.v. injection was abolished in five of six volunteers, whereas EMLA had no effect. We conclude that local anaesthetics penetrate deeply enough to numb both veins and skin with iontophoresis only.

Adult↗