A Comparative Study of the Percutaneous versus Intraoral Technique for Mental Nerve Block

Objective: Mental nerve block is frequently used to aid repair of facial lacerations; both percutaneous and intraoral approaches to blocking this nerve are used, but have never been compared. The authors compared the two techniques for pain of administration and effectiveness of anesthesia. Methods: A prospective, randomized, single-blind, crossover study was conducted using ten healthy volunteers aged 22 to 33 years. Patients having prior experience with mental nerve blocks, lidocaine allergy, active oral/facial infection, or previous facial fractures were excluded. Bilateral mental nerve blocks were done using intraoral technique on one side and percutaneous technique on the other. Both techniques were used by the same investigator and were carried out with 27-gauge needles and 2.5 mL of 2% buffered lidocaine at room temperature injected over 20 seconds. The oral mucosa was topically anesthetized with viscous lidocaine for 1 minute prior to intraoral injection. The orders of the blocks and sides of the face anesthetized were randomized. Subjective and objective pain (visual-analog scale), efficacy (anesthesia of lower lip), time to onset, and duration of anesthesia were evaluated. Results: The intraoral technique was subjectively less painful than the percutaneous approach in nine of ten subjects (p = 0.02). Scores on the visual-analog pain scale were significantly lower for the intraoral technique (p = 0.03). Intraoral injection produced lower-lip anesthesia in 10/10 subjects versus 7/10 for percutaneous (p = 0.25). Times to onset (approximately 1–2 minutes) and durations of anesthesia (approximately one hour) were similar for the two techniques. Conclusion: The intraoral approach to the mental nerve block with adjunctive topical anesthesia was subjectively and objectively less painful than the percutaneous approach without adjunctive anesthesia. While the intraoral approach had a greater efficacy of lower-lip anesthesia and a longer duration of action, these differences were not statistically significant.     

Cardiac microcirculatory effects of beta-adrenergic blockade during sympathetic stimulation.

The effects of beta-adrenergic blockade on cardiac transcapillary exchange were examined at rest and during sympathetic stimulation. Multiple indicator dilution experiments were carried out in closed-chest anesthetized dogs at rest and during carotid occlusion, either under basal conditions or after beta-adrenergic blockade with alprenolol. beta-Adrenergic blockade at rest had no effect on coronary flow or transcapillary exchange in comparison with the control situation, but it abolished the increase in coronary flow and in the permeability/surface area product for labeled sucrose produced by carotid occlusion. High coronary resistance values in beta-blocked animals with carotid occlusion were associated with a high degree of heterogeneity in capillary transit times, but the overall relation between coronary flow and the capillary permeability/surface area product was unchanged. The findings indicate that beta-blockade increases coronary resistance during sympathetic stimulation and, simultaneously, decreases the coronary blood flow and capillary permeability/surface area product while increasing the heterogeneity of capillary transit times.     

The thermal effect on the blood flow response to electrical stimulation.

BACKGROUND: Wounds, especially in the elderly, can be life threatening. One modality which allegedly increases blood flow (BF) as an aid to heal chronic wounds is electrical stimulation. This technique applies electrical current (ES) across wounds. However, while many studies show positive findings, others do not. The purpose of this investigation was to investigate some of this inconsistency in results by determining the effect of environmental temperature on the circulation of the skin which may negate the effects of electrical stimulation in a clinical setting. MATERIAL/METHODS: Ten people with no wounds, controls (C), and 12 people with wounds (W) were examined in a thermally neutral or cool room (20 degrees C) and a warm room (34 degrees C) to observe the effect of reducing sympathetic vasoconstrictor activity on the response to 5 and 15 mA sine wave biphasic ES delivered by 2x2 cm surface electrodes. RESULTS: C and W subjects showed a greater BF in the skin in a warm room. In group C, after 30 minutes of stimulation at a current of 15 milliamps, BF increased significantly (p<0.05) but by an average of only 4 flux in the cool room. In the warm environment, BF increased significantly (p<0.01) by 19.3+/-7 flux and increased further during the 60 minute recovery phase. In the W group, BF during ES increased much more during stimulation in a warm room compared to a cool room. CONCLUSIONS: The results show that local vasoconstriction due to exposure to a warm global temperature greatly increases the response of the skin the ES.     

The prevalence of peripheral arterial disease and medial arterial calcification in patients with chronic renal failure: requirements for diagnostics

BACKGROUND: Knowledge of the prevalence of peripheral arterial disease (PAD) in patients with chronic renal failure (CRF) is limited because of a lack of uniformity in disease definition and recognition. Furthermore, little is known of the prevalence of medial arterial calcification (MAC) in patients with CRF. Our goal is to study the prevalence of PAD and MAC defined by ankle brachial index (ABI) or toe brachial index (TBI) measurements in a Finnish population of patients with CRF consisting of predialysis and dialysis patients, as well as renal transplant recipients. METHODS: We examined 136 patients with CRF and 59 control subjects. Fifty-nine of the patients with CRF had moderate to severe predialysis CRF, 36 patients were on dialysis treatment, and 41 were renal transplant recipients. Mean age of patients was 51.9 +/- 11.5 years, and 39 patients (29%) had diabetes. ABI and TBI were measured by means of photoplethysmography. The definition of PAD required an ABI value of 0.90 or less, a TBI value of 0.60 or less, or a previous positive lower-extremity angiogram result. ABI values of 1.3 or greater or incompressible arteries at ankle level indicated MAC. The presence of claudication was determined by an interview. RESULTS: Prevalences of PAD on this study were 22.0% in patients with predialysis CRF, 30.6% in patients on dialysis treatment, 14.6% in renal transplant recipients, and 1.7% in the control group (P = 0.001). Prevalences of MAC were 23.7%, 41.7%, 23.1%, and 3.4% (P < 0.001), respectively. Only 9 patients had claudication, and 6 of those patients had PAD. CONCLUSION: Both asymptomatic PAD and MAC are common in patients with CRF. Therefore, we recommend the use of both ABI and TBI measurements in the evaluation of PAD in patients with CRF.     

Pharmakogenetik

Die Pharmakogenetik untersucht, inwieweit genetische Polymorphismen der Proteine, die die pharmakokinetischen und pharmakodynamischen Prozesse eines Arzneimittels kontrollieren, für die interindividuellen Unterschiede in Wirkung und Nebenwirkung verantwortlich sind. Im Gegensatz zur Pharmakogenetik nutzt die Pharmakogenomik einen genomweiten Ansatz zur Identifizierung von Genen bzw. Gennetzwerken, die an der Entstehung von Erkrankungen beteiligt sind bzw. als therapeutische Ziele für neue Arzneistoffe dienen können. Die zurzeit am besten charakterisierten pharmakogenetischen Polymorphismen betreffen die Arzneimittel metabolisierenden Enzyme Zytochrom-P450-2C9, -2C19 und -2D6 bzw. die Thiopurinmethyltransferase, für die in klinischen Studien relevante Konsequenzen für die Arzneimitteltherapie gezeigt werden konnten. Das ultimative Ziel pharmakogenetischer/-genomischer Forschung ist es, unter Verwendung einer neuen Krankheits- und Therapieklassifikation auf molekularer Ebene eine spezifische Arzneimitteltherapie bei genetisch definierten Untergruppen von Patienten durchzuführen.     

Shoulder instability: impact of glenohumeral arthrotomography on treatment

We used arthrotomography to study the glenoid labrum in 114 patients. Sixty-nine of the patients had anatomic instability of the shoulder (including recurrent dislocation and subluxation of the shoulder), and 45 patients had functional instability of the shoulder (denoted by chronic pain, clicking of the joint, and the sensation that an unstable condition exists without the objective signs of it). Labral tears were revealed arthrotomographically in 86% of the patients with anatomic instability, while only 40% of the patients with functional instability had labral abnormalities, and these were primarily of minor severity. Fifty-six patients (44 of whom had anatomic instability; 12, functional instability) required surgery. The surgical findings were correlated with the arthrotomographic findings, and no false-positive results were revealed. However, arthrotomography demonstrated only part of the pathologic condition of two patients. These results confirm that there is a strong correlation between labral pathologic conditions and anatomic instability of the shoulder. Arthrotomographic studies have a great impact on the selection of therapy in cases of both anatomic and functional instability of the shoulder.