Digital image analysis of erythema development after experimental thermal injury to human skin: effect of postburn topical local anesthetics (EMLA)

Local anesthetics inhibit edema and improve circulation in experimental burns. We evaluated the effect of topical local anesthetics on human skin burns in volunteers using computerized color analysis that allowed repeated noninvasive quantitative measurements. A standardized partial-thickness burn (1 cm2) was induced in one forearm of 10 healthy volunteers and in the opposite forearm a week later. The burned areas were treated with lidocaine/prilocaine cream (EMLA; Astra, Sweden) or a placebo cream for 1 h. The experimental skin area was photographed before and 1, 2, 4, and 12 h postburn. Digitized images were evaluated using normalized red-green-blue and Hue-Saturation-Intensity. Differences in erythema between skin treated with EMLA and placebo were not significant during the first 4 h postburn. However, 12 h postburn, a pronounced decrease in the degree of erythema was observed in EMLA-treated skin compared with placebo-treated skin. We conclude that topical local anesthetics administered for 1 h postburn significantly reduces the duration of erythema after a mild thermal injury, which suggests a potential use in clinical practice in the treatment of minor skin burns.

IMPLICATIONS

Burn injury constitutes a serious type of tissue damage that activates inflammatory mechanisms, often causing pain, disfiguration, or malfunction. We treated burns using an anesthetic cream and demonstrated a reduction in burn-induced inflammation by using computer-based color image analysis.

Bone marrow harvesting using EMLA (eutectic mixture of local anaesthetics) cream, local anaesthesia and patient-controlled analgesia with alfentanil

Bone marrow harvesting (BMH) was performed on 40 consecutive allogeneic or autologous donors using EMLA (eutectic mixture of local anaesthetics), local anaesthesia (LA) and patient-controlled analgesia with alfentanil (PCA-A). The effect of alkalinizing the LA solution on reducing pain during LA infiltration in the presence of EMLA was also investigated. EMLA 10 g with occlusive dressing was applied to the harvest sites at least 60 min before BMH. The PCA device was programmed to deliver an intravenous loading dose of 15 microg/kg alfentanil, followed by a background alfentanil infusion of 0.05 microg/kg/min. Demand dose was 4 microg/kg and lockout time was 3 min. Donors were randomized to receive either alkalinized (n = 19) or non-alkalinized (n=21) LA solution (lignocaine 1% with 1:100000 adrenaline). While post-operative nausea and vomiting were the only side-effects, all donors in both groups reported satisfactory pain scores during LA infiltration and satisfactory overall intra-operative comfort scores. They completed BMH using either regimen successfully, found this technique acceptable and would recommend this form of anaesthesia to others. Alkalinizing the LA solution did not significantly improve the pain scores during LA infiltration in the presence of EMLA. In conclusion, BMH can be performed safely using EMLA, LA and PCA-A without major complications.

Safety of lidocaine-prilocaine cream application four times a day in premature neonates: a pilot study

Although safety is established for lidocaine-prilocaine cream application to the heel once a day in neonates, it is often necessary to repeat heel lances several times a day in the clinical situation. A pilot safety study applying 0.5 g lidocaine-prilocaine cream to the heel covering an area of 5 cm2 with an occlusive dressing during 30 min four times a day was carried out. Twelve neonates (5 male, 7 female) with a gestational age of 30.1-36.3 weeks (mean 31.6 weeks) and a birth weight of 1100-2910 g (mean 1665 g) were enclosed. To establish safety, methaemoglobin levels and plasma concentrations of lidocaine, prilocaine and o-toluidine were measured until 24 h after the final application. Methaemoglobin levels were no different from baseline measurements, ranging from 0.2-1.1% and 0.1-0.7% respectively. Plasma concentrations of lidocaine and prilocaine were very low, maxima at 0.230 and 0.223 mg/l respectively. Plasma o-toluidine concentrations remained below the detection limit (0.025 mg/l).

CONCLUSION

Application of 0.5 g lidocaine-prilocaine cream to the heel under occlusion four times a day during 30 min is safe in preterm neonates. Establishing safety by measuring the methaemoglobin level by daily application is recommended.

Evaluating the efficacy of commonly used topical anesthetics

PURPOSE

This study compared the efficacy of commonly used topical anesthetics using an objective measuring scale.

METHODS

The following were tested: 5% EMLA cream, 10% cocaine, 10% lidocaine, 10% benzocaine, 1% dyclonine, and a placebo. A special instrument was designed to serve the purpose of pressure application on the gingiva to obtain a threshold discomfort level in grams before and after the topical delivery. The medicaments, in the quantity of 20 microL (2-3 drops) were placed on the maxillary anterior region using Beckman paper wicks in the form of discs. The topical anesthetics were left on the gingiva for 3 min and off for another 3 min. The instrument applied pressure progressively, and the pressure application was stopped when the subjects reported the initial feeling of discomfort.

RESULTS

5% EMLA cream significantly reduced the pain threshold level followed by 1% dyclonine and 10% benzocaine. However, there was no significant difference between 10% cocaine, 10% lidocaine, and the placebo. The placebo effect was observed.

CONCLUSIONS

5% EMLA cream was superior in performance to all other topical anesthetics. The remainder of the agents had no statistically different effect than the saline.

Pharmacokinetics of prilocaine after intravenous administration in volunteers: enantioselectivity

BACKGROUND

Prilocaine exists in two stereoisomeric configurations, the enantiomers S(+)- and R(-)-prilocaine. The drug is clinically used as the racemate. This study examined the pharmacokinetics of the enantiomers after intravenous administration of the racemate.

METHODS

Ten healthy male volunteers received 200 mg racemic prilocaine as a 10-min intravenous infusion. Blood samples were collected for 8 h after the start of the infusion. Plasma concentrations were measured by stereoselective high-performance liquid chromatography (HPLC). Unbound fractions of the enantiomers in blank blood samples, spiked with racemic prilocaine, were determined using equilibrium dialysis.

RESULTS

The unbound fraction of R(-)-prilocaine (mean +/- SD, 70%+/-8%) was smaller (P < 0.05) than that of S(+)-prilocaine (73%+/-5%). The total plasma clearance of R(-)-prilocaine (2.57+/-0.46 l/min) was larger (P < 0.0001) than that of S(+)-prilocaine (1.91+/-0.30 l/min). The steady-state volume of distribution of R(-)-prilocaine (279+/-94 l) did not differ from that of S(+)-prilocaine (291+/-93 l). The terminal half-life of R(-)-prilocaine (87+/-27 min) was shorter (P < 0.05) than that of S(+)-prilocaine (124+/-64 min), as was the mean residence time of R(-)-prilocaine (108+/-30 min) compared with S(+)-prilocaine (155+/-59 min; P < 0.005).

CONCLUSIONS

The pharmacokinetics of prilocaine are enantioselective. The difference in clearance is most likely a result of a difference in intrinsic metabolic clearance. The difference in the pharmacokinetics of the enantiomers of prilocaine does not seem to be clinically relevant.

Allergic reactions to lignocaine

True allergic reactions to local analgesics are extremely rare. This case report illustrates the procedures adopted to manage a patient with a history of suspected allergy. A young woman was found to have a true type I hypersensitivity to lignocaine. Another routinely used local analgesic agent, prilocaine, was tested by the same methods and found to give no allergic response. Dental treatment was successfully completed using the latter and the patient advised to wear a medical alert bracelet.

Evaluation of the analgesic efficacy of EMLA cream in volunteers with differing skin pigmentation undergoing venipuncture

BACKGROUND AND OBJECTIVES

Lidocaine/prilocaine cream (EMLA) applied to intact skin for 60 minutes has been shown to reduce venipuncture pain. Recent studies have suggested that lidocaine/prilocaine cream is less effective on heavily pigmented skin. The objective of this study was to evaluate the topical anesthetic efficacy of lidocaine/prilocaine cream in volunteers with varying skin pigmentation types.

METHODS

Sixty volunteers were enrolled into each of three groups based on skin pigmentation history. Subjects were randomized to receive lidocaine/prilocaine cream onto the antecubital fossa of one arm and placebo cream on the comparable location of the other arm for either 60, 90, or 120 minutes prior to venipuncture. Assessments of perceived pain associated with each venipuncture were made by the subject using a visual analog scale.

RESULTS

Lidocaine/prilocaine cream applied for 60 minutes significantly (P < .0001) reduced the pain of venipuncture compared to placebo regardless of the skin pigmentation type. Pain reduction did not differ significantly across skin types (P = .7986). Additional exposure up to 120 minutes did not change the efficacy of EMLA cream.

CONCLUSIONS

Lidocaine/prilocaine cream is a safe and effective topical anesthetic for reducing pain associated with venipuncture in individuals, regardless of skin pigmentation.

[Efficacy of EMLA cream, effect of time and place of application]

OBJECTIVE

To evaluate the anesthetic efficacy of EMLA cream for alleviating pain associated with puncture and pressure in areas where venous catheters are normally inserted.

MATERIAL AND METHODS

We performed a prospective, double blind study in 38 volunteers between 25 and 36 years of age, after obtaining informed consent. A 1.5 g dose of EMLA cream was applied to three sites on each patient: the back of the hand, the antecubital fossa and the side of the neck. Placebo cream with similar characteristics was applied to contralateral sites. Pain was evaluated on a visual analog scale (VAS, 0-10). Tactile sensitivity was assessed on a four-point scale (0 = no sensation; 1 = slight sensation; 2 = moderate, and 3 = strong). An analysis of variance study was performed to compare baseline scores to results over time, and placebo results to EMLA scores for each test site.

RESULTS

The assessment of response to puncture and pressure gradually decreased over time for the sites where EMLA cream was applied, but not for the areas where placebo was applied.

CONCLUSION

The efficacy of EMLA cream varies demonstrably depending on type of stimulus, site of application and time since application.

A comparison of 2 topical anesthetics on the discomfort of intraligamentary injections: a double-blind, split-mouth volunteer clinical trial

OBJECTIVE

The purpose of this volunteer clinical trial was to compare the effects of 5% lidocaine ointment and EMLA cream on the discomfort associated with intraligamentary injections.

STUDY DESIGN

A double-blind, split mouth study was conducted. Each of 10 healthy volunteers had 5% lidocaine and EMLA cream applied to the maxillary premolar buccal gingiva for 5 minutes before the administration of an intraligamentary injection. Discomfort during the injection was assessed through use of a visual analog scale. Data were analyzed by means of Student paired and unpaired t tests.

RESULTS

Injection discomfort on the side on which EMLA cream was applied was significantly less than on the lidocaine side (t = 2.32, P < .05).

CONCLUSIONS

EMLA cream reduced the discomfort associated with intraligamentary injections.

Effect of EMLA pre-treatment on capsaicin-induced burning and hyperalgesia

Capsaicin, which has been studied extensively as a treatment for itch and several chronic pain disorders, induces burning during the first week of therapy, causing a substantial percentage of patients to discontinue treatment prematurely. We examined whether pre-treatment with the topical anesthetic EMLA reduces the burning sensation induced by capsaicin and alters capsaicin effects on thermal sensation and pain thresholds. Healthy adult volunteers participated in the single-blind, 6-day study. After baseline measurement of warmth, cold pain and heat pain thresholds with a computerized thermal sensory analyzer, subjects applied EMLA thrice daily on one forearm and vehicle placebo on the other forearm, 60 min before applying capsaicin 0.075% on both forearms. Subjects rated burning sensations 3 times a day throughout the study. After 1 and 5 days of thrice daily application of EMLA or vehicle followed by capsaicin, thermal sensory testing was repeated. Subjects rated burning sensations to the significantly less on the EMLA pre-treated forearm compared with the placebo pre-treated forearm during all 5 days of treatment (p < 0.01). Capsaicin with and without EMLA produced significant heat pain hyperalgesia and cold pain hypoalgesia after 1 day of treatment. After 5 days of treatment, heat pain hyperalgesia persisted on both forearms; however, it was significantly less on the EMLA-treated forearm vs the vehicle-treated site (p < 0.03). Cold pain hypoalgesia persisted in both forearms. The warmth sensation threshold was significantly higher on the EMLA-pre-treated forearm after 1 and 5 days of treatment. In conclusion, pre-treatment with EMLA significantly reduced the burning sensation from capsaicin and attenuated heat hyperalgesia during treatment.

V. A new route, jet injection of lidocaine for skin wheal for painless intravenous catheterization

OBJECTIVE

The objective of this study was to compare the efficacy of intradermal lidocaine anesthesia by two jet injectors to the routine needle infiltration and to the topical EMLA cream.

SUBJECTS AND METHODS

In a randomized, prospective, controlled trial, 100 consenting surgicenter patients in a university hospital setting were divided into four groups (n = 25, each); intradermal lidocaine anesthesia was given either by the conventional 25 g needle/syringe or the Med-E-Jet or Biojector injector or EMLA cream was applied on the skin. Visual analogue pain scores (VAS) or verbal pain intensity scores (PIS) were reported by the patients at lidocaine application and i.v. catheterization. Cost was also assessed.

RESULTS

At lidocaine application, no pain was reported, since proportions of VAS = 0 were 25/25 (CI: 0.868, 0.999) with Med-E-Jet; 24/25 (0.804, 0.991) with Biojector; 25/25 (0.868, 0.999) with EMLA; in contrast to pain, 3/25 (0.044, 0.302) with the needle (PP > 0.999). The VAS scores (mean +/- SD) were 0.00 +/- 0.00, 0.04 +/- 0.20, 0.00 +/- 0.00, and 2.4 +/- 2.2 respectively (p < 0.00 1). No pain was reported by proportions of PIS = 0 with Med-E-Jet: 25/25 (CI: 0.868, 0.999); with Biojector: 23/25 (0.749, 0.976); EMLA 25/25 (0,868, 0.999); but pain with the needle: 5/25 (0.090, 0.394) (PP > 0.999). The mean +/- SD PIS scores were 0.00 +/- 0.00, 0.16 +/- 0.55, 0.00 +/- 0.00, and 1.24 +/- 1.00, respectively (p < 0.001). At i.v. catheterization, the proportions of VAS = 0 scores were 22/25 with Med-E-Jet (0.698, 0.956); 21/25 (0.651, 0.934) with Biojector; but some pain with needle: 6/25 (0.116, 0.436) (PP > 0.999). The mean +/- SD VAS scores were: 0.12 +/- 0.33, 0.44 +/- 0.20, and 1.64 +/- 1.50, respectively (p < 0.001). No pain was reported by PIS = 0 scores in 24/25 (0.804, 0.991) with Med-E-Jet; 24/25 (0.804, 0.991) with the Biojector; but pain by zero PIS scores 13/25 (0.334, 0.703) in half of the patients in the needle group (PP > 0.999). The mean +/- SD scores were 0.00 +/- 0.00, 0.00 +/- 0.00, and 0.76 +/- 0.88, respectively (p < 0.001). The EMLA cream was not evaluated because of inadequate duration of application prior to anesthetic induction. Cost/application were: Med-E-Jet = $ 0.13; needle = $ 0.50; Biojector = $ 0.94 and EMLA = $ 3.76.

CONCLUSION

Almost completely painless i.v. catheterization by jet injection of lidocaine was accomplished, while needle infiltration produced pain/discomfort and did not significantly reduce it at the i.v. needle insertion.

EMLA cream as a topical anesthetic for the repeated mechanical debridement of venous leg ulcers: a double-blind, placebo-controlled study

BACKGROUND

A granulating surface is important for skin grafting and healing of leg ulcers. Mechanical debridement to remove necrotic tissue often must be stopped before completion because of pain.

OBJECTIVE

Our purpose was to assess the effect of EMLA cream on the number of debridements required to obtain a clean ulcer and on pain during debridement and to determine its safety after repeated doses.

METHODS

In this randomized double-blind, placebo-controlled study, 69 patients with venous leg ulcers received cream before debridement until a clean ulcer was obtained (or a maximum of 15 debridements).

RESULTS

EMLA decreased the median number of debridements required for a clean ulcer (EMLA 11.5, placebo >15; P = .019) and decreased pain by 50% (P = .003). Plasma levels of lidocaine, prilocaine, and their main metabolites were low without any apparent accumulation.

CONCLUSION

EMLA produces effective pain relief for the debridement of leg ulcers and shortens the time to a clean ulcer.

Cutaneous tape stripping to accelerate the anesthetic effects of EMLA cream: a randomized, controlled trial

Most medications are not absorbed topically due to the stratum corneum barrier. While effective as a topical anesthetic, EMLA cream is absorbed slowly, delaying its effects for up to one hour, thereby limiting its usefulness.

OBJECTIVE

To determine whether removal of the cornified layer of the skin by tape stripping (TS) would allow more rapid onset of anesthesia after topical application of EMLA cream prior to IV catheterization (IVC).

METHODS

This was a prospective, randomized, controlled trial comparing the levels of pain of IVC 15 minutes after topical application of EMLA cream in patients who had TS vs patients who did not. The setting was a suburban university-affiliated ED. A convenience sample of 68 alert adult patients requiring IVC were enrolled. The primary outcomes measured were pain of IVC and pain of TS using a previously validated 100-mm visual analog scale as well as the IVC success rate.

RESULTS

The pain of IVC was less for TS vs control patients [29.7 mm (95% CI=20.4 to 39.0 mm) vs 15.9 mm (95% CI=9.1 to 22.6 mm), p=0.017]. The mean pain of TS was 4.8+/-7.4 mm. The IVC success rate for TS vs control patients was 91% vs 74% (p=0.056). There were no adverse events after TS.

CONCLUSIONS

Removal of the cornified layer of the skin resulted in a more rapid anesthetic effect of EMLA cream as evidenced by lower IVC pain scores after TS. The effectiveness of TS for enhanced absorption of other medications should be investigated.

Subcutaneous administration of midazolam: a comparison of the Bioject jet injector with the conventional syringe and needle

PURPOSE

The purpose of this study was to compare jet injection to a syringe and needle in terms of the difference in discomfort and pharmacokinetics after the subcutaneous administration of midazolam.

PATIENTS AND METHODS

Using a prospective, randomized, double-blinded study design, 14 subjects were administered midazolam on two separate occasions (at least 2 weeks apart). The subjects were randomly distributed into two groups: syringe and needle (saline)/jet injector (midazolam) or syringe and needle (midazolam)/jet injector (saline). The subjects were randomly assigned to receive either EMLA (eutectic mixture of local anesthetics) or a placebo at the injection site for the first administration and the other topical agent on the second visit. Each subject received one subcutaneous injection in the deltoid region per arm per day. Each injection contained the same volume of solution. Subjects completed visual analog scale (VAS) questionnaires assessing the discomfort of the injection. Blood samples were taken at specified intervals over 2 hours for determination of midazolam levels.

RESULTS

The discomfort associated with the injection was less with the Biojector 2000 (Bioject Inc, Portland, OR) although this was not statistically significant. However, persistent discomfort was significantly greater at the needle site. The mean peak plasma level of midazolam was achieved more rapidly with the Biojector 2000 than with the syringe and needle (P < .05). However, the peak plasma level after jet injection or injection with a syringe and needle was not statistically different.

CONCLUSION

The results of the study show that the Biojector 2000 is a needle-free injection system that can be used for the administration of a premedicant before induction of anesthesia. It has several advantages, including the potential reduction of anxiety associated with the "fear of needles" and occupational injuries.

[Utilization of transcutaneous anesthetics during heart catheterization]

OBJECTIVES

Assess the efficacy of an anesthetic cream for cardiac catheterization.

PATIENTS AND METHODS

Percutaneous anesthesia was studied in a series of 100 consecutive patients undergoing cardiac catheterization. The anesthesia was composed with an eutetic mixture of local anesthetics and applied precisely over the puncture area in a randomized controlled study. After admission, patients were randomized into two groups: 50 patients received lidocaine infiltration and 50 patients received associated cream and infiltration. Percutaneous anesthesia was to be applied 2 hours before entering the operating room.

RESULTS

No complication developed with this cream combined with lidocaine infiltration. Serum concentration indicated very low levels which were very well tolerated. Patient comfort improved with the anesthetic cream-lidocaine infiltration association.

CONCLUSION

The use of an anesthetic cream is safe and effective, especially combined with lidocaine infiltration during cardiac catheterization. Cost is high and the association might be reserved for special indications (obesity, children).

Prilocaine-phenylephrine topical anesthesia for repair of mucous membrane lacerations

OBJECTIVE

To compare the effectiveness of prilocaine-phenylephrine (Prilophen), a new topical anesthetic that does not contain cocaine, to that of lidocaine infiltration during repair of lacerations on or near mucous membranes in children.

DESIGN

A prospective, randomized, blinded trial.

SETTING

The emergency department of a large academic children's hospital.

PATIENTS

Children one year of age or older with a laceration 5 cm or less in length on or near a mucous membrane.

INTERVENTIONS

Forty patients were randomly assigned one of the two local anesthetics, with 20 patients in each treatment group.

OUTCOME MEASURES

Pain felt during suturing was scored by suture technicians, research assistants, a videotape reviewer, parents, and patients five years of age and older using a visual analog scale (VAS).

RESULTS

There was no statistically significant difference in performance between topical Prilophen and lidocaine infiltration when VAS pain scores of research assistants, parents, and patients were compared. However, lidocaine infiltration performed significantly better than topical Prilophen when comparing VAS scores of suture technicians (P = 0.003) and the videotape reviewer (P = 0.02). When power analyses were performed using alpha = 0.05 and beta = 0.20, it was possible to detect a difference of 2 units for VAS scores of suture technicians, 2 VAS units for research assistants, 3 VAS units for the videotape reviewer and parents, and 7 VAS units for patients. There were no wound healing or other complications.

CONCLUSIONS

Prilophen is a new topical anesthetic alternative to lidocaine infiltration for closure of lacerations on or near mucous membranes, where use of tetracaine-adrenaline-cocaine is contraindicated. The performance of Prilophen was rated by two of the observer groups as statistically inferior to that of lidocaine infiltration; however, the differences in pain scores were small and may not be clinically significant. Further investigation of this new topical anesthetic is warranted.

[Pharma clinics. How I treat...or preventing pain with "patches"]

There exists two distinct types of patches aiming at increasing the pain threshold either systematically or locally. The first type of analgesic patch is a real transdermal delivery system releasing fentanyl. Such potent opioid drug exerts a systemic effect. The other type of patch associates lidocain and prilocain to induce a local anesthesia of the skin without inducing a systemic effect.

[Subcutaneous infusion anesthesia with prilocaine diluted with Ringer's lactate]

BACKGROUND

Dermatologic surgery is usually possible under local anesthesia, even when large amounts of highly diluted anesthetic solutions are required (tumescent anesthesia). Although special pumps now render such large injections effortless, it is usually still necessary to hold and guide the injection cannula. We have overcome this handicap by injecting anesthetic solutions slowly with an infusomat, which allows slow painless automatic infusion into the subcutaneous layer.

METHOD

The speed of infusion varied between 40 ml and 1500 ml per hour depending on location, size of the operation, and needle size. Volumes usually ranged from 1 ml to 500 ml but rose as high as 1000 ml if necessary. We found it easier to inject larger amounts than with the conventional method. We used 21-gauge to 30-gauge needles with a length of 1 to 10 cm. The anesthetic solution was prilocaine (Xylonest), and the dilution liquid was original Ringer's solution in 500 ml bottles with no additives. The concentration of the solution varied between 0.4% and 0.1%. After setting up the system, the physician even can leave the room. Especially for children and very anxious patients, this feature is calming.

MATERIAL

We used this type of subcutaneous infusion anesthesia (SIA) in our department to treat 502 patients ranging in age from 3 to 92 years (mean age: 51 years). We performed all kinds of tumor operations (n = 213), dermabrasions (n = 5), scar revisions (n = 21), stripping of the long and short saphenous veins (n = 82), sentinel node dissection (n = 27), complete lymph node dissection of the axilla (n = 12) and groin (n = 17), and 125 other operations as well.

RESULTS

There were no severe complications. Postoperative recovery was fast. 110 (91%) of 121 patients who had previously experienced other forms of anesthesia for the same kind of operation preferred SIA.

CONCLUSIONS

SIA Ringer's solution diluted prilocaine is an economical, safe and comfortable technique for nearly all skin operations, even for children and very sensitive patients.

Eutectic mixture of local anesthetics in adult urology patients: an observational trial

BACKGROUND AND OBJECTIVES

The effectiveness of EMLA eutectic mixture of local anesthetics, (ASTRA Co, France) cream in minor surgery on the penis and its acceptability in unpremedicated outpatients were assessed.

METHODS

EMLA cream was applied 1 hour before surgery (fremulum plasty, circumcision or dorsal section for phimosis, and condyloma accuminatum) in addition to a subcutaneous infiltration of lidocaine 1%, just before incision in cases of circumcision. Verbal Rating Scale (VSR) was assessed during the surgery and the acceptance 15 days later by a questionnaire.

RESULTS

Thirty-two patients included. In all of the cases, the application of EMLA cream was sufficient, with the exception of one (fremulum plasty). General anesthesia was used for this patient unable to tolerate the proprioceptive sensations (VRS = 0). In cases of circumcision, the subcutaneous infiltration was not experienced as painful. Eighty-eight percent of patients who answered the questionnaire confirmed that if they had to be reoperated on, they would opt for this technique of anesthesia.

CONCLUSION

EMLA cream is effective in minor penile surgery in adult patients, and it is associated with subcutaneous infiltration of local anesthetic in the case of circumcision.

What are the parameters for predictive selection of patients requiring anesthesia for extracorporeal shockwave lithotripsy?

OBJECTIVE

Additional anesthesia is required to minimize the tolerable pain level in efficiently performed extracorporeal shockwave lithotripsy (ESWL) with electrohydraulic and electromagnetic sources. In order to assess optimum anesthesia for each patient undergoing a standardized ESWL protocol, pain measurement and scoring were carried out. We attempted to determine the individual type and amount of analgesia prior to treatment.

METHODS

Patients (n = 95) with urolithiasis underwent pain measurement and scoring prior to ESWL. 'Threshold of pain' (TP) and 'maximal tolerable pain (MTP) were assessed by inducing ischemia pain with the submaximum effort tourniquet technique. Pain intensity was assessed by a verbal rating scale (VRS). The results of pain measurement and amount of analgosedation were correlated in two phases. Patients were administered an oral premedication of 0.1 mg/kg midazolam. Phase 1: 60 patients were randomized into three groups: (1) piritramide (0.1-0.3 mg/kg) and midazolam (1-3 mg) i.v. (2) Lidocaine/prilocaine cream topically (30 g) to skin and diclofenac supp. 100 mg. (3) No analgesia. Phase 2: Based on the data of phase 1, cut-off points for TP and MTP were set for female and male patients. In accordance with these results, 35 patients comprised group 1 for anesthesia with piritramide/midazolam, group 2 with lidocaine/prilocaine cream and diclofenac supp. and group 3 for no analgesia at all. The electromagnetic shockwave sources Modulith SLX and Lithostar Plus were utilized.

RESULTS

Phase 1: All patients randomized for group 1 (intravenous analgosedation) were treated in accordance with the protocol. 65% of group 2 (cream/suppository) tolerated treatment as planned. 35% of patients selected for ESWL without analgesia (group 3) remained within this group. Patients requiring additional analgosedation displayed lower TP and MTP. The cut-off points for females and males were TP >/=25/35 s and MTP >/=45/60 s, respectively. Phase 2: 20/35 patients were preselected for a nonintravenous protocol. Five out of these 20 violated the protocol. The rate of additionally administered analgesia was lower than in phase 1: 35:10% in group 2 (cream/supp.), 65:40% in group 3 (no analgesia).

CONCLUSIONS

The TP and MTP levels are lower in patients requiring stronger analgesia. The determined parameters are suitable for patient preselection and individual assessment of anesthesia prior to ESWL. It may be assumed that 50% of patients administered intravenous opioids are overtreated. Routine pain measurement for patient depends on the individual pain tolerance level. A third phase of this study recruiting a large number of patients will contribute to the confirmation of these results.

Procaine spinal anesthesia: a pilot study of the incidence of transient neurologic symptoms

STUDY OBJECTIVES

To determine the approximate incidence of transient neurologic symptoms (TNS) [formerly known as transient radicular irritation (TRI)] associated with procaine spinal anesthesia, and whether fentanyl prolongs the duration of procaine spinal anesthesia.

DESIGN

Unrandomized pilot study.

SETTING

Community teaching hospital.

PATIENTS

106 consecutive patients scheduled for spinal anesthesia for procedures anticipated to last less than 90 minutes.

INTERVENTIONS

All patients received 5% procaine for spinal anesthesia. Fentanyl 20 micrograms was added for procedures anticipated to last longer than 45 minutes (but less than 90 min). Intraoperatively the adequacy of duration, level, and intensity of anesthesia were observed. Time from injection of local anesthetic until knee-bending was recorded. Three days postoperatively, patients were questioned intensively in an effort to determine whether back pain and/or symptoms consistent with TNS had occurred.

MEASUREMENTS AND MAIN RESULTS

Duration of anesthesia was adequate in all but one instance. The intensity and the sensory level of anesthesia were satisfactory with one exception, a woman who had an unexpectedly low sensory level (L1) after 60 mg of procaine for cerclage, and who was also was the only patients to develop TNS. The incidence of TNS (0.9%) was markedly less than that reported after lidocaine and similar to the incidence observed after bupivacaine. Mild back pain without radiation occurred in 11 patients (10%), an incidence that is similar to that seen after bupivacaine and lidocaine. Compared with procaine alone, the addition of fentanyl significantly (p = 0.0001) prolonged the time to bending knees from 72 minutes to 97 minutes.

CONCLUSIONS

Procaine may be a useful alternative to lidocaine for short procedures, and it is less likely to produce TNS. Fentanyl prolongs motor block when added to procaine.

A clinical study of hair removal using the long-pulsed ruby laser

BACKGROUND

Laser hair removal is rapidly becoming a widely used modality. Clinical studies are needed to assess these hair removal systems. The long-pulsed ruby laser is one such modality for the removal of unwanted hair.

OBJECTIVES

To evaluate the efficacy of the long-pulsed ruby laser (694 nm, 3-msec pulsewidth, 7- or 10-mm spot size) in removing unwanted hair, and to provide treatment guidelines for the proper utilization of this laser system.

METHODS

Forty-eight areas of unwanted facial and body hair from 25 patients with blonde, brown, or black hair were treated with the long-pulsed ruby laser at fluences between 10 and 40 J/cm2. Hair regrowth was measured at 4 weeks after the first treatment, 4 weeks after the second treatment, 4 weeks after the third treatment, and 16 weeks after the third treatment by counting the number of terminal hairs compared with baseline pretreatment values. All complications and treatment outcomes were documented.

RESULTS

The mean percent of regrowth after the first treatment was 65.5%, 41% after the second treatment, and 34% after the third treatment. Overall, regardless of skin type or targeted body region, patients who underwent three treatment sessions demonstrated an average 35% regrowth in terminal hair count compared with baseline pretreatment values 6 months after initial therapy.

CONCLUSION

Long-pulsed ruby laser treatment resulted in significant hair growth delay in most cases. Repeated laser treatments produced an increased number of vellus hairs, an increase in growth delay, and a decreased percentage of hair regrowth.