Escalator controls

One documented method uses process safety barriers identification for metrics selection. This concept uses a combination of lagging and leading indicators associated with process safety barriers and incident escalation controls to evaluate the process safety system performance. The basis for this method is documented in the U.K. Health and Safety Executive (HSE) publication HSG254 and illustrated by Figures 4.1-4.3. The strength of this technique arises from using the combination of indicators that provides multiple perspectives for judging the surety of a barrier or escalation control. For example, this basic concept was adopted and modified by BP to focus upon three information sources to assess key control barriers as summarized below ... 

The factors (human or other) that contributed to the initiation of the incident and its escalation/control and... 

Malaria affects an estimated 270 million people and causes 2—3 million deaths annually, approximately one million of which occur in children under the age of five. While primarily an affliction of the tropics and subtropics, it has occurred as far north as the Arctic Circle. The disease essentially has been eradicated in most temperate-zone countries, but some 1100 cases of malaria in U.S. citizens returning from abroad were reported to the Centers for Disease Control during 1990. Malaria is seen today in Southeast Asia, Africa, and Central and South America. It is on the increase in Afghanistan, Brazil, China, India, Mexico, the Philippines, Sri Lanka, Thailand, and Vietnam. Escalation of the disease is because of the discontinued use of the insecticide DDT which effectively kills mosquito larvae, but has been found to be toxic to Hvestock and wildlife. Also, chloroquine (6), a reUable dmg for the prophylaxis and treatment of falcipamm malaria, is ineffective in many parts of the world because of the spread of dmg-resistant strains. 

The EPA argues that the cost of compliance to environmental regulations is small in comparison to baseline industry expenditures. However, there are many hidden costs that oftentimes are not considered when contemplating a control technology investment, and which can escalate and adversely impact on bottom-line economic performance. These so-called other costs include, but are not limited to ... 

The costs of a wrong decision are loss of production, on the one hand, and failure to respond to a real emergency on the other. In order to improve his or her decision basis, the control room worker will usually dispatch others to the source of the emergency signal to declare whether it is spurious (false alarm) or whether it is real, but it is containable without need for depressurizing. This takes up valuable time, during which the situation could escalate dangerously. 

Control systems can quickly escalate into unmanageable complexity, and the initial approach to the design of a suitable control system should examine the purpose of each item, and the effect on others, to eliminate those which are not essential. 

The current use of IV rt-PA for acute stroke thrombolysis is based on the NINDS rt-PA study, a two-part randomized, double blind, placebo-controlled trial. " This trial was preceded by two open-label, dose-escalation safety studies that suggested that treatment within 180 minutes of stroke onset, and rt-PA dosages no higher than 0.95 mg/kg, was safe and effective. ... 

Abciximab in acute ischemic stroke a randomized, double-blind, placebo-controlled, dose-escalation study. The Abciximab in Ischemic Stroke Investigators. Stroke 2000 31 601-609. 

The abciximab in Acute Ischemic Stroke trial was a randomized, placebo-controlled dose-escalation study to examine the safety of abciximab in acute stroke. It randomized 74 patients within 24 hours of stroke onset to receive one of four doses of abciximab (by bolus with or without additional infusion, 54 patients) or placebo (20 patients). The median baseline National Institute of Health Stroke Scale (NIHSS) score was 15. The rates of asymptomatic ICH were 19% in the intervention group compared to 5% in the placebo group p = 0.07). Most (9 of 11) of the asymptomatic ICH patients had more severe stroke (NIHSS >14). No cases of symptomatic ICH or major systemic bleeding occurred. There was a trend toward a lower rate of stroke recurrence (2% vs. 5%) and a higher rate of functional recovery at 3 months in the group treated with abciximab than with placebo. 

An intriguing area of research on opioids has been the accumulating evidence for plasticity in opioid controls. The degree of effectiveness of morphine analgesia is snbject to modulation by other transmitter systems in the spinal cord and by pathological changes induced by peripheral nerve injury. Thus in neuropathic states, pain after nerve injury, morphine analgesia can be reduced (but can still be effective) and tactics other than dose-escalation to circumvent this will be briefly discussed in Chapter 21. 

Monitor for adequate pain control and the need for escalation or de-escalation of analgesia. 

Six months later, BA s pain is controlled with the escalating doses of the combination product however, he has reached the maximum dose of acetaminophen. What would you suggest at this time ... 

Widespread use of mirex may lead to altered population structure in terrestrial systems, with resurgence or escalation of nontarget pests due to selective mirex-induced mortality of predators (NAS 1978). For example, populations of immature horn flies and rove beetles, two species of arthropods normally preyed upon by fire ants, were higher in mirex-treated areas than in control areas (Howard and Oliver 1978). Conversely, other species, such as crickets, ground beetles, and various species of oil-loving ants, were directly affected and populations were still depressed or eliminated 14 months posttreatment (NAS 1978), whereas fire ants recovered to higher than pretreatment levels, as judged by mound numbers and mound size (Summerlin et al. 1977). 

Currently, physicians and patients determine the demand for pharmaceuticals and employers and insurers assume the risk and cost. As the price of new health care technologies escalates, payers will design and implement strategies to share risk and cost. Defined employer contributions, increased patient cost sharing, and benefit exclusions will be used to help control utilization and cost. In this environment, value-based assessments will be crucial to the adoption of any technological innovation. It is reasonable to expect public and private coverage for new therapies if evidence is provided regarding the costs and consequences of treatment. However, social and ethical dilemmas will certainly arise as therapies whose costs exceed their benefits are debated in the public arena. 

In practice the presence of all three ways of intervening are needed. It is not possible to eliminate all latent conditions and there will always be conditions leading to possible ineffective safety barriers and ineffective control elements, which subsequently lead to precursors. Therefore, recovery is necessary, to intervene and arrest the precursors and ineffective safety barriers from evolving into a possible accident. Finally, because not all precursors can be effectively recovered, finally an overview of affected safety barriers is necessary to prevent an alignment of ineffective safety barriers and the presence of precursors that can escalate into an accident. 

In this Chapter further evidence is provided that precursors exist long before they escalate into an accident. It will be demonstrated that the existence of precursor information could have been used to foresee and even prevent recent accidents with hazardous substances. Moreover, a set of precursors retrieved from 17 recent accidents in the Dutch chemical process industry is used to validate the 7-stage protocol developed in the previous Chapter. In spite of the limited accident information it is shown that if a proper control action had been initiated, all of these 17 accidents could have been prevented. 

A seemingly innocent change in the procedures, e.g. in parts, in staffing, was, almost without exception, the alteration that initiated the propagation and escalation of the deviation. Had the corresponding control loop not been ineffective then the escalation most likely would have been most likely prevented. 

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