EMLA anaesthetic cream for debridement of burns: a study of plasma concentrations of lidocaine and prilocaine and a review of the literature.

The lidocaine-prilocaine cream (EMLATM) effectively reduces the pain from debridement of chronic leg ulcers. Studies have demonstrated that when applied to leg ulcers, plasma concentrations of the local anaesthetics are well below the threshold for CNS toxicity. However, there are minimal pharmacokinetic data available from EMLA application to burn wounds. This study evaluated EMLA cream for debridement of burns with regard to plasma concentrations of lidocaine and prilocaine, and reviewed the published literature on safety and efficacy of lidocaine-prilocaine applied epicutaneously to burns. Eight patients aged 22-59 received 5 g of EMLA 5% cream applied to 25 cm2 large 2nd degree burn areas for 30 min. Venous blood samples drawn at set intervals up to 120 min after cream application were analyzed for total plasma concentrations of lidocaine and prilocaine. Pain from debridement was assessed on a 4-point verbal scale and a 100-mm visual analog scale (VAS) with the end points "no pain" and "severe pain". A literature search on the use of lidocaine-prilocaine cream on burn wounds was performed in PubMed. The results showed that six patients felt no pain and two patients mild pain. The median VAS score was 11 (range 2-59). Peak plasma concentrations of lidocaine (mean 205 ng/ml) and prilocaine (mean 97 ng/ml) were observed after 15-60 min. Two published studies and two case reports of overdose of lidocaine-prilocaine cream applied to burns in paediatric patients were retrieved. Peak plasma concentrations of lidocaine and prilocaine combined after application of 5 g EMLA to burns 25 cm2 large for 30 min in adults are far below those associated with toxicity. Bioavailability estimation suggests 5 to 30% of the prilocaine dose applied to burns is percutaneously absorbed. The analgesic efficacy appears satisfactory for debridement of 2nd degree burns.

Quality of life--the effect of hyperbaric oxygen treatment on radiation injury.

The purpose of the present study was to assess changes in health-related quality of life (HRQL) among patients with radiation injury one year after hyperbaric oxygen (HBO2 therapy). HBO2 therapy was given once daily, five times a week in monoplace hyperbaric chambers for at least 19 days. HRQL was measured by SF-36 (Short Form with 36 questions). The study population was 101 patients, and among these 53.5% had radiation injury to the head and neck region, 35.6% to the intestine and 10.9% to the bladder. Testing for differences before and one year after HBO2 therapy showed significant improvement for the following SF-36 scales: Physical Function an increase of 4.54 (p = 0.01). Role Performance an increase of 8.79 (p = 0.04). Vitality an increase of 6.88 (p = 0.001). Social Function an increase of 8.04 (p = 0.002). Time since radiation at HBO2 therapy was 1-39 years. A total of 82% received radiation more than one year ago, and 33% more than seven years ago. Changes in physical and mental sum scores were not associated with time since radiation. Patients below the age of 70 seemed to have the best effect of HBO2 therapy measured by HRQL.

Risk of misclassification of decompression sickness.

Decompression sickness (DCS) is classified on the basis of which organ system is affected, and neurological DCS is considered more severe than DCS in joints and skin with respect to response to recompression treatment and risk of long-term sequelae. Gas bubble formation interstitially in the tissues or in the circulation is considered to be the mechanism for all types of DCS. Ten patients diagnosed as having DCS in joints or skin, by doctors experienced in diving medicine, underwent clinical examination by a neurologist and had an electroencephalogram. Eight of the ten subjects had findings suggesting central nervous system deficits. The findings indicate that DCS of the central nervous system often accompanies DCS of the joints and skin, and that local skin and joint symptoms may draw attention away from cerebral symptoms. We recommend that all cases with DCS should initially be treated as neurological DCS.

Hypermetropia-succeeded myopia after hyperbaric oxygen therapy.

A 58-year-old man presented with a change in vision during hyperbaric oxygen (HBO) therapy. Subsequent follow-up visits showed a hypermetropic shift, which succeeded the myopic shift after each of two series of HBO treatments. The maximal refractive amplitude was 3.00 D (range -1.37 D to +1.62 D) in the right eye and 2.75 D (range -1.25 D to + 1.50 D) in the left eye. Refraction stabilized after 1.5 years at +0.62 D and +0.50 D to pretreatment values in the right and left eye, respectively. The findings are discussed with regard to possible changes in the structure of the lens.

Time and temperature effects on body fluid loss during dives with the open hot-water suit.

BACKGROUND: Bodyweight (BW) losses up to 5 kg have been observed during diving with the open hot-water suit (HWS). The objective of these dives was to study the hormonal, hematological, and renal effects of dehydration during shallow HWS diving. METHODS: In series 1, four divers dove for 3.5 h each day for 7 d. In series 2, 12 divers dove to 6-8 msw for 1, 2, and 4 h. Blood and urine samples, BW measurements, oral temperature, and thermal stress indices were collected. RESULTS: Average deltaBW (+/- SD) for the 28 dives in series 1 was 1.5 +/- 0.8 kg, and the largest BW reductions were 3.2 and 3.0 kg, corresponding to 3.7 and 4.7% of BW. Changes in thermal stress, hemoglobin, hematocrit, aldosterone, and electrolyte excretion correlated with BW reduction. In series 2, average BW reductions were 0.46 +/- 0.27, 0.96 +/- 0.38, and 1.55 +/- 0.59 kg during 1-, 2-, and 4-h dives. BW reduction correlated significantly with thermal stress (p < 0.01). Aldosterone increased after 1 and 2 h and plasma renin activity was unchanged. Atrial natriuretic peptide increased in all dives (p < 0.01) and arginine vasopressin increased in the 4-h dives (p < 0.05). The 7.2% decrease in plasma volume, the increases in hemoglobin, hematocrit and serum proteins, and an unchanged plasma osmolality indicate an isotonic dehydration after the 4-h dives. CONCLUSIONS: BW loss during HWS diving is mainly caused by sweating. Dives of 4 h produce an isotonic dehydration and a break for fluid intake is, therefore, recommended.

Ocular refractive changes in patients receiving hyperbaric oxygen administered by oronasal mask or hood.

PURPOSE: The aim of this study was to quantify ocular refractive changes after a standard hyperbaric oxygen (HBO) treatment protocol and to characterize the time period of recovery. PATIENTS AND METHODS: Hyperbaric oxygen therapy was given for 90 min daily at a pressure of 240 kPa for 21 days. Oxygen was administered to 20 patients using an oronasal mask and to 12 patients using a hood. Follow-up examinations were carried out 2-4 days after treatment, and thereafter regularly for up to 10 weeks in both groups. Refraction was assessed automatically and by the monocular subjective refraction method. A subgroup of nine of the 20 patients to whom oxygen was administered by an oronasal mask underwent a separate eye examination, which included crystalline lens opacity measurements and LOCS III gradings. RESULTS: In the patients given oxygen by mask, there was a significant myopic shift in the mean spherical equivalent, which was largest 2-4 days after treatment. The shift was - 0.55 +/- 0.40 D in the right eye and - 0.53 +/- 0.42 D in the left eye. In the patients given oxygen by hood, the largest shift was observed after 12-16 days, and was - 1.06 +/- 0.52 D in the right eye and - 1.10 +/- 0.57 D in the left eye. The refractive changes returned to baseline 6 weeks and 10 weeks after HBO treatment, respectively. No significant changes in crystalline lens transparency were revealed. CONCLUSIONS: The myopic shift after HBO therapy recovers within 10 weeks and may be more pronounced when patients are given oxygen using a hood compared with using an oronasal mask.

[Neurologic decompression sickness in sports divers]. / Nevrologisk trykkfallssyke hos sportsdykkere.

BACKGROUND: Sports diving is a popular recreational activity. Sports divers presenting with acute decompression sickness may exhibit residual neurologic and neuropsychological symptoms during follow-up, in spite of appropriate treatment. MATERIAL AND METHODS: A retrospective review of medical records was carried out for sports divers admitted to the department of neurology at Haukeland University Hospital during 1997. RESULTS: 11 out of 20 divers experienced residual neurological symptoms after treatment. Five responded poorly to treatment, with 50% or more residual clinical score. These patients tended to be older, had performed deeper dives, and more repetitive diving. Seven divers had increased slow wave activity in EEG on initial recording, in two the EEG changes persisted after treatment. INTERPRETATION: In this small series of sports divers with decompression sickness and arterial gas embolism, most neurologic symptoms responded to hyperbaric treatment. However, more than one half of the divers had residual neurological symptoms on discharge. Sensory loss and asymmetrical reflexes were the most common residual findings.