Brugada-type patterns are easily observed in high precordial lead ECGs in collegiate athletes.

BACKGROUND: Displacement of ECG leads can result in unwarranted findings. We assessed the frequency of Brugada-type patterns in athletes when precordial leads were purposely placed upward. METHODS: Four hundred ninety-one collegiate athletes underwent two ECGs: one with standard leads, one with V1 and V2 along the 2nd intercostal space. A positive Brugada-type pattern was defined as ST elevation in V1 or V2 consistent with a Type 1, 2, or 3 pattern in the high-lead ECG. A control group was comprised of 181 outpatients. RESULTS: No Type 1 patterns were seen. In 58 athletes (11.8%), a Brugada-type 2 or 3 pattern was observed. Those with Brugada-type 2 or 3 patterns were more likely male, taller, and heavier. In the control group, 18 (9.9%) had Brugada-type 2 or 3 patterns and were more likely male. CONCLUSIONS: Proper lead positioning is essential to avoid unwarranted diagnosis of a Brugada-type ECG, especially in taller, heavier male athletes.

Successful same day discharge after immediate post-mastectomy alloplastic breast reconstruction: A single tertiary centre retrospective audit.

BACKGROUND: Immediate Post-Mastectomy Alloplastic Breast Reconstruction (IPMABR) traditionally requires a post-operative overnight stay. Recent initiatives have identified same day discharge as a safe option. METHODS: A retrospective audit of all cases at a tertiary breast cancer centre was performed. Patients received surgery at a day care facility or regional hospital (RH). Unplanned admission was defined as any patient unable to be discharged or any patient returning to the emergency room within the first 24 h. Planned admission cases had a history of BMI >40, obstructive sleep apnoea or previous anaesthetic complications. Data were collected on planned same day discharge, unplanned admission and planned admission cases. Factors differentiating the groups were identified and variables predicting unplanned admission were determined. RESULTS: A total of 785 patients received IPMABR over a 5-year period of which 743 had satisfactory data sets for review. Greater than 96% of patients receiving care at the day care facility were successfully discharged. The success rate for same day discharge at the RH was 65%. We determined that the greatest variables determining successful planned discharge were shorter surgical time (67 min; SD 6 min; p<.01), shorter PACU time (130 min; SD 21 min; p<.01) and surgical institution (p<.01). This difference between institutions was significant when all other variables (age, co-morbidities, unilateral/bilateral and BMI) were controlled, indicating a strong institutional bias. There was no difference between groups in complication rates (infection, dehiscence, seroma and haematoma). CONCLUSION: Same day discharge following IPMABR is safe and greatly reduces resource use. It is imperative that members of the perioperative team understand the validity and benefits of the programme to ensure success and reduce unplanned admissions.

Biomechanical analysis of football neck collars.

OBJECTIVE: To determine the load-limiting capabilities of protective neck collars used in football through dynamic impact testing. DESIGN: A 50th-percentile male Hybrid III dummy was used in 48 dynamic impact tests comparing The Cowboy Collar, Bullock Collar, and Kerr Collar. A control and each collar were tested at two velocities (5 m/s and 7 m/s), three impact locations (front, top, and side of the helmet), and two shoulder pad positions (normal and raised). SETTING: Research laboratory. PATIENTS: None. INTERVENTIONS: None. Independent variables were the neck collars, impact velocity, and shoulder pad position. MAIN OUTCOME MEASUREMENTS: In addition to range of motion, upper and lower neck forces and moments were measured. RESULTS: With the top impact location, it was found that the Kerr Collar and Bullock Collar reduced head accelerations and force transmission through the neck. With the front impact location, all the collars reduced lower neck moment. The Kerr Collar was also capable of reducing the lower neck force and upper neck moment. With the side impact location, the Kerr Collar substantially reduced lower neck moment. CONCLUSIONS: These reductions in loads correlate with the degree to which each collar restricted the motion of the head and neck. By restricting the range of motion of the neck and redistributing load to the shoulders, neck loads can be effectively lowered.

Analysis of linear head accelerations from collegiate football impacts.

Sports-related concussions result in 300,000 brain injuries in the United States each year. We conducted a study utilizing an in-helmet system that measures and records linear head accelerations to analyze head impacts in collegiate football. The Head Impact Telemetry (HIT) System is an in-helmet system with six spring-mounted accelerometers and an antenna that transmits data via radio frequency to a sideline receiver and laptop computer system. A total of 11,604 head impacts were recorded from the Virginia Tech football team throughout the 2003 and 2004 football seasons during 22 games and 62 practices from a total of 52 players. Although the incidence of injury data are limited, this study presents an extremely large data set from human head impacts that provides valuable insight into the lower limits of head acceleration that cause mild traumatic brain injuries.

An experimental study on the effects of crayfish on the predator-prey interaction between bass and sculpin.

1. We examined the hypothesis that in a one predator-two prey system, prey that share a common refuge might have indirect interactions mediated by their reciprocal effects on each other's refuge use. Our experiments were done in laboratory pools with plexiglas refuges, using predatory smallmouth bass, Micropterus dolemieui, that can consume crayfish, Orconectes putnami and mottled sculpin, Cottus bairdi. 2. Bass consumed 35% of the sculpin in 36 h. Bass predation rates on sculpin were significantly reduced in the presence of crayfish; i.e., crayfish had an indirect positive effect on sculpin. Predation rates on cray fish were low (1.7% in 36 h) and were not affected by the presence of sculpin. 3. The indirect effect of crayfish on sculpin can be explained in terms of patterns of sculpin refuge use. When bass were present, but crayfish were absent, only 14% of the sculpin were in refuge. Instead of going into refuge, sculpin responded to bass by "freezing" in place, with most sculpin outside of refuge; that is, sculpin responded to bass presence by decreasing overall movement, including entry rate into refuge and exit rate out of refuge. In contrast, in the presence of crayfish, sculpin responded to bass by increasing their use of refuge. The presence of crayfish allowed sculpin to have a 10 fold increase in entry rate into refuge and a 2.5 fold increase in refuge use, relative to when crayfish were absent. We suggest that these increases occurred because crayfish drew the attention of the bass away from sculpin. 4. Crayfish did not alter their refuge use or movement patterns in response to the presence of either bass or sculpin. In retrospect, this is not surprising, given the low bass predation rates on crayfish.

Differences in hybrid iii and thornt neck response in extension using matched tests with football neck collars.

Anthropometric test devices have been used in sports injury biomechanics research. This study addresses the differences in the head and neck response of the Hybrid III and THOR-NT 50th percentile male crash test dummies when used to evaluate the load limiting capabilities of football neck collars. 24 matched tests were performed with the Hybrid III and THOR-NT; in which they were equipped with shoulder pads, a helmet, and various neck collars. The dummies were then impacted on the front of the helmet using a pneumatic linear impactor to promote extension of the neck. Results from these tests indicate that the Hybrid III generates greater loads than the THOR-NT due to its stiffer neck. The Hybrid III was also more sensitive to impact velocity. The neck collars had different effects on each dummy, typically affecting the Hybrid III's response more. Even though this study looks at a specific application, it highlights differences in neck response between the Hybrid III and THOR-NT.

Force transmission to the mandible by chin straps during head impacts in football.

The objective of this study was to determine the force transmitted to the mandible from the chin strap in football helmets for head impacts. A total of 32 tests were performed comparing front and side impact locations. Each location was tested at two impact velocities (6.5 m/s and 9.0 m/s). Different combinations of neck collars and shoulder pads were tested at each speed and location to account for potential equipment variability between football players. A 50th percentile male Hybrid III dummy was equipped with a helmet, shoulder pads, and various neck collars. Tension load cells were installed on the left and right sides of the chin straps. From the tension values in the chin strap, the force transmitted to the mandible was calculated. With the front impact location, the average peak mandible load was 568 +/- 80 N at 6.5 m/s and 806 +/- 64 N at 9.0 m/s. With the side impact location, the average peak mandible load was 87 +/- 36 N at 6.5 m/s and 170 +/- 80 N at 9.0 m/s. Although there are some overlying assumptions, these values represent a good estimation of the forces acting on the mandible for head impacts in football.

Lateral bending biomechanical analysis of neck protection devices used in football.

The objective of this study was to perform a dynamic biomechanical analysis of football neck collars in order to determine their effect on head and neck loading. A total of 48 tests were performed comparing the Cowboy Collar, Bullock Collar, and the Kerr Collar. A control and each collar was tested at two speeds (5 m/s and 7 m/s), three impact locations (front, top, and side of the helmet), and two shoulder pad positions (normal and raised). This paper specifically analyzes the load limiting capabilities of these collars during an impact to the side of the helmet. A 50 percentile male Hybrid III dummy was equipped with a helmet, shoulder pads, and the various neck collars mentioned. The dummy was instrumented with tri-axial accelerometers at the CG of the head. Angular rate sensors were used in the head and chest. In addition, both the upper and lower neck were instrumented with load cells. The helmet was struck with a pneumatic linear impactor to provoke rotation of the head and neck. With the side impact location, the Kerr Collar substantially reduced lower neck moment. These reductions in loads correlate with the degree to which each collar restricted the motion of the head and neck.

Impact of a fluoroquinolone restriction policy in an elderly population.

BACKGROUND: In light of growing concerns of bacterial resistance to fluoroquinolones, the province of Ontario instituted a fluoroquinolone restriction policy in March of 2001. The objective of this study was to examine the immediate impact of this policy on the rates of antibiotic prescription use and infectious disease-related hospitalizations among elderly individuals who are dispensed antibiotics. METHODS: An interrupted time series analysis was conducted from January 1, 1994, to March 31, 2002, using administrative health care databases covering more than 1.4 million residents of Ontario, Canada, aged 65 years and older. Population rates of antibiotic use and infectious disease-related hospitalizations within 4 weeks after an antibiotic prescription were examined using interventional autoregressive integrated moving average models. RESULTS: Immediately after the introduction of the fluoroquinolone policy, fluoroquinolone prescription rates decreased to approximately 70% of expected rates (P<.01). Approximately 30% higher than expected use of sulfonamide (P=.01) and urinary anti-infectives (primarily nitrofurantoin and trimethoprim; P<.01) were observed within 1 year after policy implementation. No significant changes in the use of any other groups of antibiotics were observed. Although no significant changes in the rates of overall infection-related hospital admissions among antibiotic users were observed, the rate of hospital admission for gastrointestinal infections was 32% lower than expected in the 1 year after the policy change (P<.01). The hospital admission rate for urinary tract infections was approximately 8% higher than expected (P<.01). CONCLUSIONS: These findings suggest that formulary restrictions to fluoroquinolones can be implemented effectively to decrease use among an elderly population without adverse impact on hospital admission rates.

Head acceleration is less than 10 percent of helmet acceleration in football impacts.

Sports-related concussions constitute 20 percent of brain injuries each year in the United States. Concussion research has included a variety of instrumentation and techniques to measure head accelerations. Most recently, the Head Impact Telemetry (HIT) System (Simbex, Lebanon, NH), a wireless system that provides real-time data from impacts, is used to measure in-situ head accelerations in collegiate football. The purpose of this study is to compare helmet shell acceleration to head center of gravity acceleration using two measures of linear head acceleration. A study of 50 helmet to helmet impact tests using a pendulum provided a range of head accelerations from 5 g to 50 g. The primary measure of head acceleration is accelerometers mounted at the center of gravity of the Hybrid III head. A secondary measure is the in-helmet HIT System. The series of 50 pendulum impacts included three impact velocities of 2.0 m/s, 3.5 m/s and 5.0 m/s at four different impact locations. The impact locations were on the side, back, top and just above the facemask on the front. By comparing these two measured head accelerations and the helmet acceleration during a pendulum impact, it is shown that the response of the head and the helmet vary greatly and the in-helmet system matches the head and not helmet acceleration. Specifically, head acceleration is less than 10 percent of helmet acceleration in football impacts; moreover, the HIT System is able to accurately measure the head acceleration.

Biomechanical response of the lumbar spine in dynamic compression.

The purpose of this study was to investigate the biomechanical properties of the human lumbar spine subjected to dynamic compression. A series of six experiments using the lumbar spines from four human cadavers was performed. The first two tests utilized the entire lumbar spine while the remaining four tests used lumbar functional joints to separate the differences in stability. A high rate material testing machine was used to produce the dynamic compression at a displacement rate of 1 m/s. Custom mounting plates were developed to ensure proper anatomical position of the lumbar spine sections. Both tests with the whole lumbar spines resulted in compression fractures at T12 due to combined axial loads of 5009 N and 5911 N and bending moments of 237 Nm and 165 Nm respectively. These failures occurred as the spine behaved in first order buckling which resulted in concentrated loading and bending of the anterior aspects of the vertebral bodies. All tests with functional units resulted in endplate fractures and recorded substantially higher axial loads between 11,203 N and 13,065 N and substantially lower bending moments between 47 Nm and 88 Nm. The results indicate that the mechanical stability of the lumbar spine is critical component in relation to the tolerable compressive loads.