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Biomedical subjects

R Mann

Publications and source records attributed to R Mann.

At least 55 records · Page 3Linked to original sources
PubMed1997

Intra-amniotic debris identified at ultrasound scanning: a feature of congenital ichthyosis.

A case is described in which intra-amniotic debris was identified during an ultrasound scan in a woman with polyhydramnios at 33 weeks' gestation. At delivery the neonate was found to have severe ichthyosis involving the whole of her head, trunk and limbs, with large plaques of hyperkeratotic skin on the palms of her hands and the soles of her feet. The finding of excessive debris in association with polyhydramnios should raise the possibility of an exfoliative skin disorder.

Adult↗
PubMed1997

Do increased levels of drug abuse treatment lead to fewer drug-related problems?

It has been argued that increased levels of treatment for drug abuse are effective in reducing the levels of drug problems. During the 1980s in Ontario levels of treatment increased considerably. More treatment facilities were opened, and the number of drug abuse cases increased by a factor of about seven. It was expected that drug-related problems (mortality, morbidity, and convictions) would decrease, as happened for alcohol problems when alcohol treatment levels increased. However, the results were inconsistent. Hospital separations for drug problems decreased in the late 1970s and then increased in the 1980s. However, deaths from drug psychoses and drug dependency showed an opposite trend. Convictions for cocaine offences increased while those for narcotics, LSD, and hallucinogenic drugs showed a substantial decline from the early 1980s to the present. Significant negative correlations (suggestive of a beneficial impact) were found between treatment rates and three drug-problem measures (deaths rates from drug psychoses and drug dependence, other drug-related deaths, and convictions under the Food and Drug Act); however, a significant positive correlation was found between treatment rates and Narcotic Control Act convictions. Thus, although some of the predicted negative relationships between treatment rates and drug problems were observed, the correlations did not provide a consistent picture of the effects of increased drug treatment. More research is needed to identify better indicators of drug problems and monitor the factors that influence them.

Adult↗
PubMed1996

[Neuromuscular and cardiovascular effect of mivacurium in anesthesia induction in patients with renal failure].

OBJECTIVE: Mivacurium produces a prolonged neuromuscular block (NMB) in anuric patients (13), in spite of its rapid hydrolysis by pseudocholinesterase (PChE) which is independent of renal function (17). In the present study the pharmacodynamics and the cardiovascular effects of a bolus dose of mivacurium (0.15 mg/kg) in relation to impairment of renal function were evaluated. METHODS: 60 patients (ASA class 2-4) were assigned to one of three groups according to the degree of renal dysfunction. Creatinine clearance (Krea-Cl) as a measure of renal function was calculated using weight, age, sex and serum creatinine concentrations. Group C (control): Krea-Cl > 50 ml/min; group P (preterminal): 20 ml/min < Krea-Cl < 50 ml/min; group T (terminal): Krea-Cl < 20 ml/min. PChE activity and dibucaine numbers were assessed preoperatively. Neuromuscular transmission (Train-of-Four) was monitored using electromyography (Relaxograph, Datex Inc.) with stimulation of the ulnar nerve. The response was recorded from the hypothenar muscle. Five minutes after induction of anaesthesia with propofol and fentanyl, 0.15 mg/kg mivacurium was given i.v. over 30 s. 150 s later patients were intubated. Anaesthesia was maintained by propofol (2-10 mg/kg/h) and fentanyl (0-5 micrograms/kg/h) infusion. Patients were ventilated with oxygen/nitrous oxide (FiO2 = 0.35). As soon as T1 recovered to 5% or more, mivacurium was administered continuously and this part of the study was finished. Times of onset (onset 10; onsetmax), maximal neuromuscular block (NMBmax), neuromuscular block when intubation was started (NMBTubus), and duration 5% (dur 5) were calculated. Arterial blood pressure and heart rate were recorded before anaesthesia, after induction of anaesthesia, 2-times after mivacurium application, and after intubation. All data were compared using Kruskal-Wallis test corrected for multiple comparisons, Friedman test, or chi 2-test (*: p < 0.05). Logarithms of dur 5 and PChEd were correlated using linear regression. RESULTS: Demographic data were comparable between all groups. PChEd was 3.7 (3.0/4.1) kU/l in group C, 3.2 (2.2/4.8) kU/l in group P, and 3.5 (2.5/4.0) kU/l in group T, respectively. There were no differences between groups, neither in the NMBmax, in NMBTubus, or in onset times. But dur 5 was significantly longer in patients with renal impairment, both preterminal and also end-stage (medians: 11 min in group K, 16 min in group P, 17 min in group T). Emphasis, however, is put on the broad range between 5 and 47 min of dur 5 in group P, and between 6 and 53 min in patients of group T which is clinically more important than the differences in the median values. Dur 5 correlates with PChEd (p = 0.0001). Intubation conditions were excellent (relaxed vocal cords, easy passage of the tube, without coughing) in approximately 70% of all 59 patients without significant differences between groups. In 8 patients conditions were poor (successful intubation, inspite of moderately adducted vocal cords, but moderate coughing after passage of the endotracheal tube). There were no clinically relevant hemodynamic changes in each group in the time between injection of 0.15 mg/kg mivacurium slowly and intubation 2.5 min later. DISCUSSION: Our findings suggest that 0.15 mg/kg mivacurium is an effective and safe intubation dose in healthy patients as well as in patients with renal impairment, inspite of a prolonged duration in patients with renal impairment. Low PChE in some, but not in all patients with a renal dysfunction indicates involvement of impaired hepatic function. There was a close correlation between the PChEd and dur 5. Therefore mivacurium dosage should be reduced in patients with compromised renal function, mainly if there are additional systemic, especially hepatic diseases. Thus, in patients with impaired renal function, relaxometry may be of high valu

Adolescent↗
PubMed1996

Is immediate decompression of high voltage electrical injuries to the upper extremity always necessary?

OBJECTIVE: To determine if immediate decompression is required for all high voltage injuries to the upper extremity. DESIGN: Retrospective review. MATERIALS AND METHODS: Charts reviewed of 62 patients who had upper extremity contact with >1,000 volts of electricity over a 10-year period. MAIN RESULTS: One hundred upper extremities were treated. Twenty-two percent were decompressed within 24 hours because of progressive nerve dysfunction, clinical compartment syndrome, or failure of resuscitation. This group required a mean of 4.2 operations with an amputation rate of 45%, similar to other series. Thirty-five percent of burned extremities had their first operative procedure delayed until resuscitation was complete. This group required a mean of 2.1 operations with no amputations. Forty-three percent of extremities did not require operations to achieve healing. Overall results show a 10.0% amputation rate and mean hospital stay of 27 days. CONCLUSIONS: We conclude that the need for amputation and multiple operations is determined by the injury itself and that immediate decompression is only required for the usual clinical signs of compartment syndrome. Selective decompression may actually preserve tissue and decrease the need for eventual amputation because fasciotomy can lead to soft tissue dessication by exposing viable tissue.

Adolescent↗
PubMed1996

Improved accuracy of burn wound assessment using laser Doppler.

The utility of the laser Doppler for determining burn depth has been questioned because of problems with technology and methodology. This study prospectively evaluates the ability of a new laser Doppler technique to predict burn healing time. Using the Periflux System 4000 laser Doppler, readings were taken on 305 burns (147 patients) on postburn day 3 or 4. Sixty-six wounds were used to derive a predictive function (phase I) and 152 wounds were used to test the function (phase II). Blood flow dynamics (flux), microvascular dilation capacity of the wounds to beat stress, and flow motion wave pattern (vasomotion) were studied using the laser Doppler, and seven parameters were evaluated to determine their relative contribution to the prediction of healing time. These parameters are hyperemic flux (flux value after heating to 42 degrees C), average hyperemic wave amplitude (AHWA), number of average flux units >100(F100), number readings with wave amplitude 75 (A5), average flux change (AFC), percentage of average flux increase, and relative flow capacity (RFC = AFC/average hyperemic flux). After readings were made, the wounds were observed and divided into two groups: those that healed in less than 14 days and those that healed or were grafted after 14 days. A step-wise discriminant analysis was used to assess the relative contribution of the Doppler-derived measures to healing time prediction. AHWA, F100, and RFC were included in the final discriminant function explaining 72% of the healing time variance (Wilks' lambda value 0.28; p value <0.0001). Predicted outcome = 0.05(AHWA) + 0.31(F100) + 5.0(RFC) - 2.3. With this derived function, there is 94% accuracy in the prediction of burn wound healing time compared with a physician predictive accuracy of 70%.

Adolescent↗
PubMed1996

Prognosis and treatment of burns.

Survival rates for burn patients in general have improved markedly over the past several decades. The development of topical antibiotic therapy for burn wounds, the institution of the practice of early excision and grafting, and major advances in intensive care management have all contributed to this success. In this review we address these 3 important advances in the modern treatment of burn injuries and provide a brief historical overview of these accomplishments and others, emphasizing specific achievements of note and promises for the future. We also discuss 3 topics of interest to burn physicians, including the special problems and high mortality of elderly burn patients, the disturbingly high mortality in burn patients with inhalation injury, and the possible use of artificial skin to facilitate rapid wound closure.

Burns↗
PubMed1995

Effect of renal function on neuromuscular block induced by continuous infusion of mivacurium.

We have studied the effect of renal function on the pharmacodynamics of mivacurium. Sixty patients were allocated to three groups according to creatinine clearance: group C (control), creatinine clearance > 50 ml min-1; group P (preterminal renal failure), creatinine clearance < 50 ml min-1 > 20 ml min-1; group T(terminal renal failure), creatinine clearance < 20 ml min-1. Neuromuscular transmission (train-of-four) was monitored using electromyography from the hypothenar muscle with stimulation of the ulnar nerve. After an initial bolus, mivacurium was administered continuously to maintain a T1 of 5 (4)% of baseline. The dose of mivacurium necessary to maintain 95% neuromuscular block was similar in patients with normal renal function and patients with different levels of renal impairment. Recovery from neuromuscular block after ceasing mivacurium infusion was significantly prolonged in patients with preterminal renal impairment. There was a close correlation between mivacurium pharmacodynamics and pseudocholinesterase activity, but not creatinine clearance.

Adolescent↗
PubMed1995

Aggressive chemotherapy in the treatment of Burkitt's and non-Burkitt's undifferentiated lymphoma.

Because of the aggressive nature and frequent recurrence of malignant lymphomas of the undifferentiated type, we used a multi-drug induction chemotherapy regimen that has met with some success in children with similar type of histopathology followed by intensification and 8 cycles of consolidation chemotherapy in an attempt to prolong the duration of remission and survival in adult patients with this diagnosis. Fifty-one patients (median age 35 years) with undifferentiated malignant lymphoma were collected over a 4 year period (1984-1988) and entered into a phase III protocol done under the auspices of the Eastern Cooperative Oncology Group (ECOG). Six patients who had their diagnosis made at surgery and had resection of their tumor were excluded from analysis of response to therapy. Sixty percent of the patients had Stage IV disease. Sixteen patients had marrow involvement and five had central nervous system (CNS) disease. None of the patients received CNS radiation therapy. The 45 patients evaluated for response showed a response rate of 67% (30/45) and a complete response rate of 40% (18/45). Thirteen responders continue disease-free with a median follow-up of > 40 months and have an estimated 5 year survival of 80%. Only two treatment related deaths were reported for the entire group. Patients with undifferentiated non-Burkitt's lymphoma had a longer survival than those with undifferentiated Burkitt's. We concluded that adult patients with undifferentiated lymphomas could be treated successfully with an aggressive multi-drug chemotherapy regimen, consisting of multiple alternating cycles of non-crossed-resistant chemotherapy. Toxicity with this aggressive prolonged regimen was acceptable.

Adolescent↗
PubMed1994

In vivo ovine flap model to evaluate surgical infection and tissue necrosis.

Although the inciting causes and the end results of soft tissue infection are well described, we have not achieved a quantitative methodistic description of the sequence of events in between. The following study presents an isolated in vivo model which will allow specific manipulations and quantifications of the events of integumentary infection. Pedicle flaps were raised on the buttock of the adult range ewe and it was multiply inoculated with Staphylococcus aureus, and followed for 96 hr. This pedicle contains not only a well-defined artery, vein, and nerve, but also a well-developed efferent lymphatic vessel. In addition, the distal portion of the flap is primarily supplied by a musculocutaneous arterial perforator, making the distal flap a watershed area. Anatomic, radiologic, and vital stain injection studies confirmed these results. The sheep model was found to be superior to the pig model both in terms of its anatomy (the addition of an efferent lymphatic vessel) as well as the disposition of the sheep which was more compliant than that of the pig. We believe that this flap will allow multiple manipulations and provide an in vivo isolated system to study the pathobiology of soft tissue infection.

Animals↗
PubMed1994

Changes in transfusion practices in burn patients.

In 1980 patients with burns greater than 10% of total body surface area (TBSA) received a mean of 8 units of blood (range, 0-42 units) during hospitalization in our burn center. Concern about the risks of blood transfusion caused us to reassess our transfusion practices and to question the need to maintain hematocrits above 30%. We compared the quantity of blood given to burn patients at Harborview Medical Center in 1980 with that given in 1990. Available records were reviewed from all patients with greater than 10% TBSA burns who required at least one operation (1980; n = 41; 1990: n = 38). There were no differences between groups for patients' ages, timing of first excision, or length of hospital stay. There were no differences in extent of burn excision per operation, but surgical times were significantly shorter in 1990 than in 1980. In 1980, 1.2 +/- 1.2 mL of blood was transfused per square centimeter surface area excised, compared with 0.23 +/- 0.49 mL in 1990 (p < 0.0001). In 1980, 133 +/- 153 mL blood was transfused per patient per percent burn during the acute hospitalization, compared with 20 +/- 34 mL in 1990 (p < 0.0001). There have been no instances of myocardial infarction or congestive heart failure related to the maintenance of lower hematocrits. We now permit hematocrits to fall to 15%-20% in healthy patients who need limited operations. In healthy patients with more extensive burns we accept hematocrits of 25%, and only critically ill patients and those with pre-existing cardiovascular disease are transfused to hematocrits of 30% or higher.

Adolescent↗