Wednesday, September 29, 2010

18 Wheeler Truck Wrecks in Georgia

A rear dump trailer with a daycab tractorImage via Wikipedia18 Wheeler Dangers:

The size of a tractor-trailer means that they handle much differently than a passenger vehicle. One of the biggest differences is stopping distance. At 65 mph, a car requires approximately 160 feet to stop. A semi-truck, on the other hand, needs approximately 420 feet to stop.

A big rig also has huge blind spots, commonly referred to as "no zone" areas. We are all used to the blind spot in our own car, but trucks have multiple blind spots, including in the front and the back. This makes it difficult for the driver to spot surrounding vehicles, which could lead to a collision.


In addition, semi-trucks make wide turns. A driver often has to swing in the opposite direction before negotiating a turn. For example, before making a right turn, a tractor-trailer driver may first swing the truck left to accommodate the wide turning radius. This can endanger vehicles on either side of the truck.

The height and weight distribution of an 18-wheeler makes it particularly susceptible to rollovers. Although often caused by speeding, truck rollovers can occur even at very low speeds, especially when going around corners and up or down a steep pitch. Rollovers may also occur when a tire goes off the pavement and a driver tries to return the semi-truck to the road.

Driver Error

Aside from the physical limitations of 18-wheelers, other factors can lead to truck accidents. Although truck drivers by and large are skilled, attentive, courteous drivers, even minor lapses in judgment on their part can lead to a catastrophic situation. Actions such as speeding, tailgating, swerving, failing to signal, and driving under the influence of drugs or alcohol can all lead to a truck accident.

There are also a number of factors inherent to the trucking business that can lead to a big rig accident. Truck drivers often operate within a system of compensation that encourages driving faster and for more consecutive hours than is safe. They may also drive through hazardous conditions in order to meet deadlines. Additionally, drivers may receive inadequate training that does not prepare them for the danger of driving a tractor-trailer.
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GA: LNH Trucks on Roads are too Risky

Source: http://savannahnow.com/column/2010-09-29/watson-lng-truck-route-too-risky

The recent debate on these pages over the proposed trucking of liquified natural gas through Savannah is unfortunately typical of what passes for policy discussions these days, with competing interests making technically true but misleading statements.

The letter from Bruce Hughes of Southeast LNG on Sunday is an excellent example. As a scientist involved in energy and natural hazard research I feel compelled to dissect his letter in the hope of shedding a little light on this debate.

The claims by industry that LNG cannot burn or explode, and that when it evaporates it rises, are true. Yet they are also misleading.

Natural gas at ambient temperatures will rise, but LNG is extremely cold. Even as the liquid evaporates, the vapor is too cold to rise for some time and can travel for a significant distance over the ground before dissipating below dangerous levels. The radius of risk varies depending on weather and terrain, but can be several hundred feet for a truck accident.

While LNG may not explode in the conventional sense, it can undergo a process known as a rapid phase transition (RPT), which while physically a different process, has the destructive potential of an explosion. This process is triggered by contact with water - something we have in abundance along the route.

Of special concern is a truck running off the Truman Parkway and landing in the Casey Canal near Memorial Hospital. This could create a situation where a small leak results in an RPT event, catastrophically rupturing the container, and creating a cloud of cold gas.

Even a simple traffic accident could result in a pool fire, which would be a dangerous situation if it occurred near the hospitals. An LNG pool fire, while short lived, burns extremely hot - so hot it can cause burns and trigger secondary fires at a considerable distance from the fire itself. A pool fire in traffic would surely ignite adjacent vehicles and cause multiple severe burn injuries and fatalities.

The standard (and essentially only) practice for dealing with a pool fire is to let it burn itself out. Given that risk, I would not want these trucks passing closer than 1,000 feet to a hospital or other critical facility on a regular basis, certainly not in the volumes proposed by Southeast LNG, which would exceed two trucks an hour.

As to the repeated claim that LNG is "clean," while it may be true relative to coal, it is false overall. The LNG production and transport process is energy intensive, and the net impact on the environment per unit of energy produced by LNG is far greater than other energy sources, especially when compared to nuclear or renewables.

Mr. Hughes statement that LNG will "reduce our dependence on oil" is absolutely ridiculous, as we are simply exchanging dependence on foreign oil for dependence on foreign LNG, obtained from the same limited, unfriendly and politically unstable sources.

To be fair, the opponents of LNG often use fear-mongering and exaggeration in their efforts to stop LNG related facilities. The fact is, the risks of LNG are manageable, the environmental impacts no worse, and in some ways better, than comparable sources.

The industry has a fairly good safety record. But LNG does have risks, and natural gas in general is extremely problematic as a fuel, especially if one includes environmental and geopolitical considerations. My own view is that natural gas/LNG is not an appropriate fuel choice and its use should not be expanded, but we should make that decision based on facts, not on either the fears of opponents or the platitudes of industry.

As for the current debate, in my opinion the truck route as proposed is inappropriate, given the risks it presents to our critical lifeline infrastructure in the form of Memorial and Candler Hospitals. The Federal Energy Regulatory Commission should not approve it, and our elected officials should bring all of the pressure they can on Southeast LNG to change the route to avoid critical assets.

If it is approved, all the parties involved, especially the hospitals, must create realistic plans based on realistic scenarios to deal with a potential accident.
Chuck Watson lives in Savannah and runs Watson Technical Consulting, which performs risk assessments.
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Thursday, September 9, 2010

Keppra News

A generic version of the anti-convulsant medication Keppra, commonly used to treat patients that suffer from seizures, such as epileptics, was approved by the U.S. Food and Drug Administration (FDA) for marketing in 2009. However, it seems that patients who switch from Keppra to the generic, Levetiracetam, are experiencing increased re-occurance of seizures after having been seizure-free on the brand name Keppra.

Patients who were switched from Keppra to generic Levetiracetam may suffer economic losses resulting from having their driving privileges revoked because of seizure danger, inability to work, unable to attend school, and other problems. Additionally, there have been reports of injuries and at least one death resulting from a patient who suffered a seizure and died after being switched from Keppra to the generic drug.

In addition to treating patients with epilepsy or other seizure disorders, Keppra or Levetiracetam may be administered to patients who have had a traumatic brain injury (TBI) and had seizures from their brain injury.

Generic Keppra is made by a number of different manufacturers:

Aurobindo Pharma
Cobalt Pharmaceuticals
Dr. Reddy's Laboratories
Mylan Pharmaceuticals
Roxane Laboratories, Inc.
Sandoz
Teva Pharmaceuticals
Generic Keppra tablets are available in the following strengths:

Levetiracetam 250 mg
Levetiracetam 500 mg
Levetiracetam 750 mg
Keppra oral solution (liquid) is also available in generic form.

All generic medications must undergo certain tests to compare them to brand-name medications. The FDA then looks at these tests to decide if the generics are equivalent to the brand-name medications and assigns each generic a rating.

An "AB" rating means that the FDA has determined that a generic medication is equivalent to a brand-name medication. All of the generic Keppra versions currently available have an "AB" rating, meaning they should be equivalent to Keppra.

However, generic medications are allowed to have different inactive ingredients than the brand-name medication. This might include fillers or dyes or other ingredients that may cause problems for people with allergies or sensitivities.

It should also be noted that many health care providers believe that special care should be taken when switching a patient from a brand-name seizure medication to a generic one, or even switching between different generic versions of a medication.

Wednesday, September 8, 2010

ROP and ETROP: The Seminal Study about ROP

My office has worked on cases involving ROP in young children. I get asked about what might be the best source for information and to me it's the ETROP study.


At age 5 1/2 years, the oldest age for which follow-up data are available, children with threshold ROP who were enrolled in the Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) -- Outcome Study showed fewer treated eyes (31.5 percent) than control eyes (48 percent) that were blind (P<0.001). of those eyes that had a favorable structural outcome, with or without retinal ablation (cryotherapy to destroy the fringe of the retina through freezing), only a small percentage had best corrected visual acuity better than or equal to 20/40 at age 5 1/2 years (13 percent in the treated group; 17 percent in the untreated control group (p=0.19)). among the 1398 followed from the 5 large natural history centers of the cryo-rop follow-up study, children with retinal residua of rop (structural changes) had measurable visual acuity that was severly affected and tended to worsen with age. the cryo-rop study proved conclusively that peripheral retinal ablation improves the chances of avoiding blindness, but at least 80 percent of eyes are left with acuity less than 20/40.

Two concerns emerged from the CRYO-ROP extensive study on the natural history of ROP and treatment of threshold ROP. The first of these is failure of peripheral retinal ablation to eliminate all, or nearly all cases, of retinal detachment due to ROP. In the CRYO-ROP Study, 26 percent of eyes with threshold disease in zone II and 78 percent of eyes with zone I threshold disease had an unfavorable structural outcome despite treatment. The second concern is that most children who developed threshold ROP disease had visual acuity worse than 20/40 even if the eye had a favorable structural outcome.

Since no other treatment has yet been shown to be effective in preventing blindness from ROP, retinal ablation remains the treatment of choice. The ETROP Study will test whether earlier treatment is more effective than treatment at threshold in improving functional (visual acuity) outcome following ROP, as well as determining whether earlier treatment decreases the probability of an unfavorable structural outcome.

Description

Earlier treatment is defined as retinal ablation administered to the avascular retina when an eye reaches high risk prethreshold retinopathy of prematurity (ROP). Prethreshold indicates any Zone I ROP; or Zone II stage 2 with plus disease, or stage 3; or Zone II with less than 5 contiguous or 8 cumulative clock hours of stage 3 ROP with plus disease. Recognizing that a substantial number of eyes undergo spontaneous resolution of ROP, eyes will be randomized to early treatment only when high risk for an unfavorable visual acuity outcome is identified. High risk will be determined using a risk model analysis program based on longitudinal natural history data obtained from the CRYO-ROP study. This model integrates risk factors to assign a risk of progression to blindness without treatment. These factors include birth weight, gestational age, ethnicity, singleton/multiple status, outborn status, Zone on first exam, severity of ROP and rate of progression of ROP. When an infant develops prethreshold ROP and greater than or equal to 15 percent risk of unfavorable outcome, randomization to early treatment of one eye will occur. Visual acuity outcome will be measured by masked observers after wearing best corretion using the Teller Acuity Card Procedure at 9 months corrected age.

Patient Eligibility

Infants <1251 grams birthweight born at participating centers and/or examined by 42 days of life are eligible. the early treatment trial requires that an infant have prethreshold retinopathy of prematurity (rop).

Patient Recruitment Status

Completed. A total of 317 infants with birth weights less than 1251 g and birth dates between October 1, 2000, and September 30, 2002, were enrolled at 26 participating centers.
Grating acuity results showed a reduction in unfavorable visual acuity outcomes with earlier treat-ment, from 19.5% to 14.5% (P = .01). Unfavorable structural outcomes were reduced from 15.6% to 9.1% (P<.001) at 9 months. further analysis supported retinal ablative therapy for eyes with type 1 rop, defined as zone i, any stage rop with plus disease (a degree of dilation and tortuosity of the posterior retinal blood vessels meeting or exceeding that of a standard photograph); zone i, stage 3 rop without plus disease; or zone ii, stage 2 or 3 rop with plus disease. the analysis supported a wait-and-watch approach to type 2 rop, defined as zone i, stage 1 or 2 rop without plus disease or zone ii, stage 3 rop without plus disease. these eyes should be considered for treatment only if they progress to type 1 or threshold rop.

Early treatment of high-risk prethreshold ROP significantly reduced unfavorable outcomes to a clinically important degree. Additional analyses led to modified recommendations for the use of peripheral retinal ablation in eyes with ROP. Long-term follow-up is being conducted to learn whether the benefits noted in the first year after birth will persist into childhood.

OTHER OCULAR AND CLINICAL FINDINGS
The distribution of refractive errors at the 9-month examination was similar between the high-risk prethreshold eyes that received early treatment and those that were conventionally managed.
Cataract or aphakia that was not associated with total retinal detachment or vitrectomy was found in 4 eyes (1.2%) in the group treated at high-risk prethreshold and 4 eyes (1.2%) in the conventionally managed group. Nystagmus occurred in 22% of randomized infants with bilateral high-risk ROP.

  A table ompares other ocular and systemic complications of treatment among infants treated at high-risk prethreshold vs conventionally managed infants in whom high-risk prethreshold ROP progressed and who later underwent treatment at threshold. Ocular complication rates were similar in the 2 groups. Systemic complications were higher following treatment at high-risk prethreshold. Infants with high-risk prethreshold ROP who were randomized to early treatment received peripheral retinal ablation at a mean postmenstrual age of 35.2 weeks compared with 37 weeks in conventionally treated infants who underwent peripheral retinal ablation at threshold.

http://www.nei.nih.gov/neitrials/static/study83.asp