Kenjiro Dan

Human skin flora as a potential source of epidural abscess.

Background The mechanism of epidural infection associated with epidural block is not clearly understood. Resident organisms in skin specimens were studied after skin was prepared with disinfectants. Methods Sixty-nine paired skin specimens were excised at incisional sites after skin disinfection with 10% povidone-iodine (10% PVP-I) or 0.5% chlorhexidine in 80% ethanol (0.5% CHE) from 60 patients having back surgery. One of the specimen pairs was placed in 10 ml brain-heart infusion broth and incubated in air at 37 degrees Celsius for 96 h. The other specimen was sectioned at 3 micro meter and prepared with Grams stain for examination with the microscope. Results Thirteen gram-positive staphylococcal species (Staphylococcus epidermidis, 69.2%; S. hyicus, 15.4%; and S. capitis, 15.4%) were isolated from cultures. The isolates were found in a significantly greater proportion of the skin specimens disinfected with 10% PVP-I than in those disinfected with 0.5% CHE (11 of 34 cultures [32.4%] vs. 2 of 35 cultures [5.7%]; P < 0.01). Many gram-positive cocci were observed with the microscope in 4 (11.8%) and 5 (14.3%) of 34 and 35 skin specimens disinfected with 10% PVP-I and 0.5% CHE, respectively. The cocci formed a dense colony in each follicle and in the stratum corneum. No organism was present in any of 17,584 sweat glands examined. Conclusions In a large proportion of patients, isolation of viable organisms from excised skin specimens after disinfection with 10% PVP-I suggests that contamination of the epidural space by the skin flora may be a potential mechanism of epidural infection associated with epidural block.

Bactericidal activity of skin disinfectants on methicillin-resistant Staphylococcus aureus.

We studied bactericidal activity of 10% povidone-iodine, 0.5% chlorhexidine gluconate, and 0.5% chlorhexidine in 80% ethanol on four strains of methicillin-resistant and two strains of methicillin-susceptible Staphylococcus aureus. The pathogen was exposed to each of the disinfectants for 15,30,60,120, and 240 s at room temperature. The inocula from these suspensions were cultured 72 h at 37 degrees C after the antimicrobial activity of the disinfectants in the suspensions was inactivated by 1:1000 dilution with neutralizer. No organism grew in any of the strains after exposure to 0.5% chlorhexidine in 80% ethanol. The 15-, 30-, and 60-s exposure to 10% povidone-iodine reduced the mean colony count by 55.2%, 91.2%, and 96.7%, respectively, and the exposures to 0.5% chlorhexidine gluconate reduced the mean colony count by 37.2%, 77.1%, and 93.3%, respectively. The difference in colony count between disinfectants was significant at 15- and 30-s exposures (P < 0.01 and 0.05, respectively). The results suggest that bactericidal activity of 0.5% chlorhexidine in 80% ethanol is more potent and more rapid against methicillin-susceptible and methicillin-resistant strains of S. aureus. (Anesth Analg 1995;81:555-8)

Factors influencing the duration of treatment of acute herpetic pain with sympathetic nerve block: Importance of severity of herpes zoster assessed by the maximum antibody titers to varicella-zoster virus in otherwise healthy patients

&NA; Antibody responses to varicella‐zoster virus (VZV) were serially investigated by the complement‐fixation test in 72 Japanese of both sexes, suffering from herpes zoster (HZ), but otherwise healthy. Our objective was to elucidate whether there were mutual relationships among severities of skin lesion, maximum antibody titers to VZV, and duration of treatment for acute herpetic pain (AHP). Patients were divided into 3 groups: mild group (n = 26), moderate group (n = 26) and severe group (n = 20), according to the severity of the skin lesions. The 3 groups did not differ significantly with respect to age (P > 0.6). All patients were treated with regional sympathetic nerve blocks (SNBs) until pain relief was achieved. The durations of treatment for AHP became significantly longer as HZ increased in severity; the mean log10 durations of treatment (± S.E.) for the mild, moderate, and severe groups were 1.383 ± 0.037, 1.616 ± 0.055, and 1.888 ± 0.069 days, respectively (P < 0.01 for the mild group vs. the moderate group, and P < 0.001 for the moderate group vs. the severe group). Irrespective of age, the maximum antibody titers closely paralleled the severities of the skin lesion of HZ; the mean maximum log10 antibody titers (±S.E.) for the mild, moderate, and severe groups were 5.12 ± 0.24, 6.73 ± 0.20, and 8.00 ± 0.18, respectively (P < 0.001 for the mild group vs. the moderate group and for the moderate group vs. the severe group). There was a highly significant positive linear correlation between maximum antibody titers and duration of treatment for the entire group of patients (r = 0.56, P < 10−6). It is concluded that, irrespective of age, the severities of HZ in otherwise healthy patients can be defined objectively and quantitatively by the maximum antibody titers to VZV, and that the severity of HZ itself rather than age is of utmost importance in influencing the duration of treatment of AHP with intensive SNB. We propose that reports dealing with the treatment of AHP should include data on the severity of HZ and that the results be analyzed according to the severity of HZ itself, defined preferably by the maximum antibody titers to VZV, in otherwise healthy patients.

Computer-assisted infrared thermographic study of axon reflex induced by intradermal melittin

Abstract The aim of the present study was to investigate whether melittin, the principal toxin of the honeybee (Apis mellifera) venom, can be used as an algogenic agent in the study of pain in humans. Five micrograms of melittin in 0.5 ml of saline was intradermally injected into the volar aspect of the forearm. Resultant pain was scored by a visual analogue scale (VAS), and skin temperature change was analyzed by means of a computer‐assisted infrared thermography. Intradermal melittin temporarily produced severe pain, followed by a sustained increase in skin temperature. The skin temperature increase peaked in about 10 min and outlasted 1 h. Topical application of 10% lidocaine gel did not significantly suppress the melittin‐induced pain, but markedly suppressed both the increase in the peak temperature and the area of temperature increase. In conclusion, 5 &mgr;g of melittin is sufficient to produce pain in humans and 10% lidocaine gel differentially decreases the melittin‐induced axon reflex without any significant analgesic effect.

Growth of Escherichia coli in propofol, lidocaine, and mixtures of propofol and lidocaine

Background: Microorganisms grow rapidly in propofol. Extrinsic contamination of propofol is thought to be a source of postoperative sepsis and wound infection. We studied growth of a strain of Escherichia coli in thiopental, propofol, lidocaine, and mixtures of propofol and lidocaine.

Severity of skin lesions of herpes zoster at the worst phase rather than age and involved region most influences the duration of acute herpetic pain

Abstract Duration of acute herpetic pain (AHP) in 1431 patients for whom treatment was begun within 14 days after the onset of herpes zoster (HZ) was analyzed with respect to age, involved region, and severity of skin lesions. All patients were treated with repeated sympathetic nerve blocks until their pain was almost nil. Severity of the skin lesions at the worst phase was defined as mild when they covered less than one‐quarter of the primary dermatome, as severe when they covered more than three‐quarters of the primary dermatome, and moderate if they were between mild and severe. Without taking into account the severity of skin lesions, the duration of AHP for those aged 60 years or over and for those with trigeminal involvement was significantly longer than for patients aged under 40 years (P<0.01 and P<0.001) and for patients with thoracic (P<0.001) and lumbosacral (P<0.01) involvement, respectively. However, duration of AHP was significantly longer with increase in the severity of skin lesions in all age groups (the mild group versus the moderate group, P<0.01 and P<0.001; the moderate group versus the severe group, P<0.01 and P<0.001). The mean duration of AHP for patients aged 60 years or over with mild skin lesions ranged from 17.4 to 22.9 days, while that for patients aged 30–59 years with severe skin lesions ranged from 37.2 to 50.1 days. In addition, duration of AHP was significantly longer with increase in the severity of skin lesions in all regions (the mild group versus the moderate group, P<0.01 and P<0.001; the moderate group versus the severe group, P<0.05 and P<0.001). The mean duration of AHP for those with trigeminal involvement with mild skin lesions was 19.5 days, while the range was from 51.3 to 55.0 days for patients with severe skin lesions involving regions other than the trigeminal area. The frequency of severe skin lesions was significantly higher (P<0.001) in patients aged 60 years or over and in those with trigeminal involvement. Multiple stepwise regression analysis revealed that the most important factors influencing the duration of AHP were the severity of skin lesions of HZ at the worst phase (r=0.412), age (r=0.277) and the involved region (r=‐0.101). Thus, AHP in the elderly and in cases of trigeminal involvement is longer because of higher frequencies of severe HZ in the elderly and in trigeminal involvement rather than ‘being aged’ and ‘trigeminal involvement’ itself. We propose that one needs to analyze the results of treatment of AHP with respect to the severity of skin lesions at the worst phase.

Continuous Epidural Infusion of Local Anesthetics and Shorter Duration of Acute Zoster-associated Pain

Objective:The purpose of this study was to investigate the effects of continuous epidural blockade on acute zoster-associated pain, compared with intermittent epidural blocks. Design:The design was a retrospective, nonrandomized study. Setting:The study was conducted at a university hospital in Japan from 1982 through 1992. Patients:A total of 178 otherwise healthy patients hospitalized with moderate or severe herpes zoster lesions. Interventions:Group A (n = 66) had intermittent epidural blocks using 1% mepivacaine, 4–6 ml, three to six times daily; group B (n = 43) were given intermittent epidural blocks and parenteral acyclovir (500 mg/day) or vidara- bine (600 mg/day) for 5 days; group C (n = 69) were administered a continuous epidural 0.5% bupivacaine infusion (0.3–1.0 ml/h) for ∼2 weeks and antiviral agents followed by intermittent blocks. Main Outcome Measures:The number of treatment days was used as the outcome measure. Results:The length of treatment was significantly shorter in group C than in groups A or B. For moderate lesions the means (days) were 36.2 [95% confidence interval (CI), 31.4–41.7), 45.6 (95% CI, 34.0–61.4), and 26.8 (95% CI, 22.3–32.3) for groups A, B, and C, respectively (p < 0.01). For severe lesions they were 73.3 (95% CI, 55.1–97.7), 81.7 (95% CI, 59.1–113.0), and 44.9 (95% CI, 35.2–57.3) for groups A, B, and C, respectively (p < 0.01). Conclusions:Continuous epidural blockade for patients with acute zoster can shorten the duration of treatment and may reduce the incidence of postherpetic neuralgia.

T-lymphocyte subsets in otherwise healthy patients with herpes zoster and relationships to the duration of acute herpetic pain.

&NA; T‐lymphocyte subsets (CD3, CD4, and CD8 lymphocytes) in peripheral blood, parameters of cell‐mediated immunity, were serially measured in 62 otherwise healthy Japanese patients with herpes zoster (HZ), and the findings were compared with those of 20 age‐matched healthy controls who had had varicella but not HZ. Our objective was to elucidate whether there were changes in cell‐mediated immunity, even in immunocompetent patients with HZ, and to investigate relationships between these variables and the duration of acute herpetic pain (AHP). All the patients underwent repeated sympathetic nerve blocks until pain was relieved. As compared with controls, there were slight increases in the percentages of CD4 lymphocytes (helper/inducer) and highly significant increases in the percentages of CD8 lymphocytes (suppressor/cytotoxic), resulting in marked decreases in CD4/CD8 ratios in the acute phase of HZ. The percentages of CD3 lymphocytes (pan‐T lymphocytes) did not differ significantly. The duration of AHP was analyzed in 49 patients in whom T‐lymphocyte subsets were measured more than twice. There was a weak but statistically significant positive linear correlation between age and the duration of AHP (r = 0.43, P < 0.01). There were statistically highly significant positive linear correlations between the number of days on which percentages of CD3 (r = 0.72, P < 10−8) and CD4 lymphocytes (r = 0.60, P < 10−5), and CD4/CD8 ratios (r = 0.62, P < 10−5) reached the maximum values after the onset of HZ and the duration of AHP. These correlation coefficients were higher than that between age and the duration of AHP. Thus, there are significant changes in peripheral blood T‐lymphocyte subsets after the onset of HZ even in otherwise healthy patients and cell‐mediated immunity plays an important role in the recovery from AHP.

Optimum pain relief with continuous epidural infusion of local anesthetics shortens the duration of zoster-associated pain.

Objective:To investigate effects of continuous epidural infusion (CEI) of 0.5% bupivacaine added to intermittent epidural boluses (IEB) on the duration of zoster-associated pain (ZAP), as compared with continuous infusion of normal saline placebo added to IEB. Design:A prospective, double-blind, randomized, placebo-controlled study. Setting:A university hospital and an affiliated clinic in Japan from 1996 through 1999. Patients:56 immunocompetent herpes zoster (HZ) patients, 50 years or older, within 10 days of rash onset and with severe pain and eruption. Interventions:Patients were hospitalized and randomly allocated into 2 groups. CEI group given CEI of 0.5% bupivacaine (0.5–1.0 mL/h) plus IEB of 0.5% bupivacaine 4 times daily (n = 29). IEB group given normal saline infusion plus IEB of 0.5% bupivacaine 4 times daily (n = 27). All patients received oral acyclovir 800 mg, 5 times daily, for 7 days. Outcome Measures:The number of days required for complete cessation of ZAP and the proportion of subjects with allodynia beyond 30 days. Results:The median time to cessation of ZAP was significantly shorter in the CEI group than in the IEB group (29 days vs. 40 days, P = 0.002). The number of patients whose allodynia persisted beyond 30 days of treatment was significantly lower in the CEI group than in the IEB group (10% vs. 37%, P = 0.027). Conclusions:CEI of 0.5% bupivacaine plus IEB was associated with a shorter duration of ZAP and fewer patients with allodynia beyond 30 days, compared with IEB plus normal saline infusion. Patients at high risk for developing postherpetic neuralgia (PHN) can be managed with intensive therapies at the early stage of disease, such as CEI, which maintains effective analgesia and may reduce the burden of PHN.

Blood flow velocity changes in carotid and vertebral arteries with stellate ganglion block: measurement by magnetic resonance imaging using a direct bolus tracking method.

Background and Objectives. Stellate ganglion block (SGB) leads to vasodilation of the head and neck, as a result of a regional sympathetic blockade. However, in such cases, controversy remains concerning changes in cerebral and extracerebral blood flow in the head. We estimated the effect of SGB on blood flow in the head by measuring the blood flow velocity in cervical vessels, using magnetic resonance imaging and the direct bolus tracking method. This noninvasive method is free from potential artifacts of bones and other connective tissues. Methods. Seven adult patients with acute or chronic pain in the head or neck underwent SGBs, using an anterior paratracheal approach with 6‐8 mL of 1% mepivacaine (3 right and 4 left SGBs). Blood flow velocity in common carotid and vertebral arteries (CCA and VA) was measured simultaneously before and after SGB, using the direct bolus tracking method. Results. On the side of SGB, blood flow velocity in CCA significantly increased (P < .002), whereas velocity in VA was unchanged after SGB. On the side contralateral to the SGB, significant changes in blood flow velocity in CCA and VA were never observed. Conclusions. Blood from the VA flows primarily to cerebral vessels, whereas that from CCA goes to both cerebral and extracerebral vessels. Given the presumed differences in blood flow distribution through the VA and CCA, we assume that the observed CCA blood flow increases, ipsilateral to the SGB, primarily as a result of vasodilation of extracerebral vessels and independent of changes in brain blood flow.