José A. Correa

Prognostic Value of the Six-Minute Walk in Advanced Non-small Cell Lung Cancer

Background: The 6 minute walk (6MW) is usually used to evaluate exercise capacity in a variety of patient populations. We hypothesized that the 6MW would decline after chemotherapy and assessed the prognostic value of this test. Materials and Methods: The 6MW was conducted in newly diagnosed advanced non-small cell lung cancer patients on three different days: twice before (one initial and one prechemotherapy test) and once after two cycles of chemotherapy. Results: Sixty-four patients were enrolled and 45 (70%) completed the study. For patients who dropped out the distance on initial 6MW was 361 m (SD 99) compared with 445 m (SD 85) for completers (p = 0.004). In the 45 completers, the mean 6MW decreased significantly after two cycles. There was a clinically significant (>54 m) decline in 6MW in 13 patients (29%), and an improved/unchanged 6MW in 32 patients (71%). For patients who walked <400 m on initial 6MW, rates of drop out were significantly higher (p = 0.02), progression of disease was statistically more frequent (p = 0.03), and median survival was significantly shorter: 6.7 months (95% confidence interval 2.6–10.8) compared with 13.9 months (95% confidence interval 10.0–17.8) in patients walking ≥400 m (p = 0.01). An initial 6MW of ≥400 m was the only variable with a significant effect on survival in a Cox regression after adjusting for all known covariates of interest. Conclusions: The 6MW declines significantly after two cycles of chemotherapy. This decline may have been even greater as patients with lower 6MW were more likely to drop out of the study. An initial 6MW ≥400 m might be a useful prognostic factor for survival in patients with advanced non-small cell lung cancer.

Minimum effective volume of lidocaine for ultrasound-guided infraclavicular block.

Background: The aim of this study was to determine the minimum effective volume of lidocaine 1.5% with epinephrine 5 &mgr;g/mL in 90% of patients (MEV90) for single-injection ultrasound-guided infraclavicular block (ICB). Methods: Using an in-plane technique, a single-injection ultrasound-guided ICB was performed: a 17-gauge, 8-cm Tuohy needle was advanced until the tip was located dorsal to the axillary artery. Volume assignment was carried out using a biased coin design up-and-down sequential method, where the volume of local anesthetic administered to each patient depended on the response of the previous one. In case of failure, the next subject received a higher volume (defined as the previous volume with an increment of 2.5 mL). If the previous patient had a successful block, the next subject was randomized to a lower volume (defined as the previous volume with a decrement of 2.5 mL), with a probability of b = 0.11, or the same volume, with a probability of 1 − b = 0.89. Lidocaine 1.5% with epinephrine 5 &mgr;g/mL was used in all subjects. Success was defined, at 30 mins, as a minimal score of 14 of 16 points using a composite scale encompassing sensory and motor block. Patients undergoing surgery of the elbow, forearm, wrist, or hand were prospectively enrolled until 45 successful blocks were obtained. Results: Fifty-five patients were included in the study. Using isotonic regression and bootstrap confidence interval (CI), the MEV90 for single-injection ultrasound-guided ICB was estimated to be 35 mL (95% CI, 30-37.5 mL). The probability of a successful response at 35 mL was estimated to be 0.91 (95% CI, 0.8-1.0). All patients with a minimal composite score of 14 points at 30 mins achieved surgical anesthesia intraoperatively. Conclusions: For single-injection ultrasound-guided ICB, the MEV90 of lidocaine 1.5% with epinephrine 5 &mgr;g/mL is 35 mL. Further dose-finding studies are required for other concentrations of lidocaine, other local anesthetic agents as well as techniques involving multiple injections, a more medial approach to ICB, or precise location of all 3 cords of the brachial plexus.

Quantitative measurement of hypertrophic scar: interrater reliability and concurrent validity.

Research into the pathophysiology and treatment of hypertrophic scar (HSc) remains limited by the heterogeneity of scar and the imprecision with which its severity is measured. The objective of this study was to test the interrater reliability and concurrent validity of the Cutometer® measurement of elasticity, the Mexameter® measurement of erythema and pigmentation, and total thickness measure of the DermaScan C® relative to the modified Vancouver Scar Scale (mVSS) in patient-matched normal skin, normal scar, and HSc. Three independent investigators evaluated 128 sites (severe HSc, moderate or mild HSc, donor site, and normal skin) on 32 burn survivors using all of the above measurement tools. The intraclass correlation coefficient, which was used to measure interrater reliability, reflects the inherent amount of error in the measure and is considered acceptable when it is >0.75. Interrater reliability of the totals of the height, pliability, and vascularity subscales of the mVSS fell below the acceptable limit (≅0.50). The individual subscales of the mVSS fell well below the acceptable level (≤0.3). The Cutometer reading of elasticity provided acceptable reliability (>0.89) for each study site with the exception of severe scar. Mexameter and DermaScan C reliability measurements were acceptable for all sites (>0.82). Concurrent validity correlations with the mVSS were significant except for the comparison of the mVSS pliability subscale and the Cutometer maximum deformation measure comparison in severe scar. In conclusion, the Mexameter and DermaScan C measurements of scar color and thickness of all sites, as well as the Cutometer measurement of elasticity in all but the most severe scars shows high interrater reliability. Their significant concurrent validity with the mVSS confirms that these tools are measuring the same traits as the mVSS, and in a more objective way.

Quantitative measurement of hypertrophic scar: intrarater reliability, sensitivity, and specificity.

The comparison of scar evaluation over time requires measurement tools with acceptable intrarater reliability and the ability to discriminate skin characteristics of interest. The objective of this study was to evaluate the intrarater reliability and sensitivity and specificity of the Cutometer®, the Mexameter®, and the DermaScan C® relative to the modified Vancouver Scar Scale (mVSS) in patient-matched normal skin, normal scar (donor sites), and hypertrophic scar (HSc). A single investigator evaluated four tissue types (severe HSc, less severe HSc, donor site, and normal skin) in 30 burn survivors with all four measurement tools. The intraclass correlation coefficient (ICC) for the Cutometer was acceptable (≥0.75) for the maximum deformation measure for the donor site and normal skin (>0.78) but was below the acceptable range for the HSc sites and all other parameters. The ICC for the Mexameter erythema (>0.75) and melanin index (>0.89) and the DermaScan C total thickness measurement (>0.82) were acceptable for all sites. The ICC for the total of the height, pliability, and vascularity subscales of the mVSS was acceptable (0.81) for normal scar but below the acceptable range for the scar sites. The DermaScan C was clearly able to discriminate HSc from normal scar and normal skin based on the total thickness measure. The Cutometer was less discriminating but was still able to discriminate HSc from normal scar and normal skin. The Mexameter erythema index was not a good discriminator of HSc and normal scar. Receiver operating characteristic curves were generated to establish the best cutoff point for the DermaScan C total thickness and the Cutometer maximum deformation, which were 2.034 and 0.387 mm, respectively. This study showed that although the Cutometer, the DermaScan C, and the Mexameter have measurement properties that make them attractive substitutes for the mVSS, caution must be used when interpreting results since the Cutometer has a ceiling effect when measuring rigid tissue such as HSc and the Mexameter erythema index does not discriminate normal scar from HSc.

Why university athletes choose not to reveal their concussion symptoms during a practice or game.

Objective:To determine why athletes decide not to seek medical attention during a game or practice when they believe they have suffered a concussion. Design:A retrospective survey. Setting:University Sport Medicine Clinic. Participants:A total of 469 male and female university athletes from several varsity team sports were participated in the study. Main Outcome Measures:Athletes were surveyed about the previous 12 months to identify specific reasons why those athletes who believed they had suffered a concussion during a game or practice decided not to seek attention at that time, how often these reasons occurred, and how important these reasons were in the decision process. Results:Ninety-two of the 469 athletes (19.6%) believed they had suffered a concussion within the previous 12 months while playing their respective sport, and 72 of these 92 athletes (78.3%) did not seek medical attention during the game or practice at least once during that time. Sports in which athletes were more likely to not reveal their concussion symptoms were football and ice hockey. The reason “Did not feel the concussion was serious/severe and felt you could still continue to play with little danger to yourself,” was listed most commonly (55/92) as a cause for not seeking medical attention for a presumed concussion. Conclusions:A significant percentage of university athletes who believed they had suffered a concussion chose not to seek medical attention at the time of injury. Improved education of players, parents, and coaches about the dangers of continuing to play with concussion symptoms may help improve reporting. Clinical Relevance:Medical staff should be aware that university athletes who believe they have suffered a concussion may choose not to volunteer their symptoms during a game or practice for a variety of personal and athletic reasons.

Impact of Lactose Containing Foods and the Genetics of Lactase on Diseases: An Analytical Review of Population Data

Dairy foods (DFs) contain complex ingredients that could affect different diseases. The control of lactose digestion phenotypically divides populations into those who can [lactase persistent (LP)] and those who cannot [lactase nonpersistent (LNP)] assimilate lactose. LNP subjects, however, can adapt to lactose intolerance through intestinal bacteria. The DF/LNP status interactions may function as disease risk modifiers. We evaluated the relationship between DF and LNP with colorectal, breast, prostate, ovarian, lung, and stomach cancer and inflammatory bowel diseases (IBD; Crohns disease and ulcerative colitis). Yearly per capita DF consumption, LNP national prevalence, cancer mortality, and incidence of IBD were obtained from several sources. A negative binomial regression model was used to derive incremental risks. There were statistically significant (P ≤ 0.05) increases in risk for colorectal and prostate cancer and ulcerative colitis with DFs and a statistically significant decreased risk for stomach cancer. There were trends (P < 0.1) for lung and ovarian cancers and Crohns disease. As LNP prevalence increased, stomach cancer risk increased, whereas risks of all other conditions decreased (P < 0.01). In 3 cancers (prostate, ovarian, and breast), meta-analyses of case-based studies support ecological data. In colorectal cancer, on the contrary, meta-analyses of case-based studies suggest protection. The possible importance of distinguishing LNP/LP status in studies is discussed.

Minimum effective volume of lidocaine for double-injection ultrasound-guided axillary block.

Background The aim of this study was to determine the minimum effective volume of lidocaine 1.5% with epinephrine 5 &mgr;g/mL in 90% of patients (MEV90) for double-injection ultrasound-guided axillary block (AXB). Methods All subjects received a double-injection ultrasound-guided AXB with lidocaine 1.5% and epinephrine 5 &mgr;g/mL. A 17-gauge, 8-cm Tuohy needle was initially advanced until its tip was positioned next to the musculocutaneous nerve. Volume assignment was carried out using a biased coin design up-and-down sequential method, where the volume of local anesthetic administered to each patient depended on the response of the previous one. In case of failure, the next subject received a higher volume (defined as the previous volume with an increment of 1.0 mL). If the previous patient had a successful block, the next subject was randomized to a lower volume (defined as the previous volume with a decrement of 1.0 mL), with a probability of b = 0.11, or the same volume, with a probability of 1 − b = 0.89. After injection of the musculocutaneous nerve, the needle was redirected toward the dorsal aspect of the axillary artery. For this second injection, volume assignment was carried out in a similar fashion; however, volume increments/decrements were 3.0 instead of 1.0 mL. Using a composite scale encompassing sensory and motor block, success was defined, at 30 minutes, as a composite score of 4 points (out of 4 points), and 10 points (out of 12 points) for the musculocutaneous and perivascular injection, respectively. Patients undergoing surgery of the forearm, wrist, or hand were prospectively enrolled until 45 successful musculocutaneous blocks or 45 successful perivascular injections were obtained. Results Fifty patients were included in the study. Using isotonic regression and bootstrap confidence interval (CI), the MEV90 was estimated to be 5.5 mL (95% CI, 3.0–6.7 mL) and 23.5 mL (95% CI, 23.1–23.9 mL) for the musculocutaneous and perivascular injection, respectively. Conclusions For double-injection ultrasound-guided AXB, the MEV90 of lidocaine 1.5% with epinephrine 5 &mgr;g/mL is 5.5 and 23.5 mL for the musculocutaneous nerve and perivascular injection, respectively. Further dose-finding studies are required for other concentrations of lidocaine, other local anesthetic agents, and other techniques for ultrasound-guided AXB.

Mechanisms of injury for concussions in university football, ice hockey, and soccer

Objective:To examine the mechanisms of injury for concussions in university football, ice hockey, and soccer. Design:Prospective cohort deign. Setting:McGill University Sport Medicine Clinic. Participants:Male and female athletes participating in varsity football, ice hockey, and soccer. Main Outcome Measures:Athletes were followed prospectively over a 10-year period to determine the mechanisms of injury for concussions and whether contact with certain areas of the body or individual variables predisposed to longer recovery from concussions. For soccer, data were collected on whether concussions occurred while attempting to head the ball. Results:There were 226 concussions in 170 athletes over the study period. The side/temporal area of the head or helmet was the most common area to be struck resulting in concussion in all 3 sports. Contact from another players head or helmet was the most probable mechanism in football and soccer. In hockey, concussion impacts were more likely to occur from contact with another body part or object rather than another head/helmet. Differences in mechanisms of injuries were found between males and females in soccer and ice hockey. Athletes with multiple concussions took longer to return to play with each subsequent concussion. Half of the concussions in soccer were related to attempting to head the soccer ball. Conclusions:The side of the head or helmet was the most common area to be struck resulting in concussion in all 3 sports. In ice hockey and soccer, there are differences in the mechanisms of injury for males and females within the same sport.

Age, atherosclerosis and type 2 diabetes reduce human mesenchymal stromal cell-mediated T-cell suppression

To this end human MSCs were isolated from adipose tissue and the MSC:CD4+ T-cell suppression was assessed in a co-culture system. In summary, this study demonstrates that advanced age, atherosclerosis and type 2 diabetes mellitus reduce the functional potency of MSCs. Optimizing the criteria for the selection of MSC donors could enhance the results of cell-based therapies.To this end human MSCs were isolated from adipose tissue and the MSC:CD4+ T-cell suppression was assessed in a co-culture system. In summary, this study demonstrates that advanced age, atherosclerosis and type 2 diabetes mellitus reduce the functional potency of MSCs. Optimizing the criteria for the selection of MSC donors could enhance the results of cell-based therapies.

Skin characteristics: normative data for elasticity, erythema, melanin, and thickness at 16 different anatomical locations

The clinical use of non‐invasive instrumentation to evaluate skin characteristics for diagnostic purposes and to evaluate treatment outcomes has become more prevalent. The purpose of this study was to generate normative data for skin elasticity, erythema (vascularity), melanin (pigmentation), and thickness across a broad age range at a wide variety of anatomical locations using the Cutometer® (6 mm probe), Mexameter®, and high‐frequency ultrasound in a healthy adult sample.