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Metal fatigue occupies a position of importance in our everyday existence and has been a structural scourge since time immemorial. Wohler in the 1850's was the first man to study fatigue on a systematic basis. His constant amplitude fatigue testing on railway axles opened a new avenue of study. During the past 1-1/4 centuries, we have constantly improved, progressed and furthered our knowledge, but we are still a long way from comprehending the mysteries surrounding fatigue. This book, written in simple language, not disguised by abstract mathematical covers, goes a long way in providing the reader with an understanding of metal fatigue. It contains 13 chapters and two appendices.The first two chapters cover a historical overview and fatigue design methods, i.e., conforming to codes, safe line design, inspection, probabilistic design and reliabiltiy.Chapters III-IV discuss micro/macro aspects of fatigue. This includes total strain range representation (elastic and plastic) plus an introductory consideration of fatigue mechanisms (slip, slip bands and crack formation). Also provided are the fundamentals of Linear Elastic Fracture Mechanics (LEFTM) with a direct application to fatigue growth and fracture. Stress intensity fracture in Mode 1, fracture toughness (K c ), and plane strain fracture toughness (K lc ) are then examined. Ample pictures of fracture surfaces compliment the discussions.Chapter V considers constant amplitude fatigue testing. This falls into high cycle (importance of mean stress) and low cycle. The latter is considered in light of Manson-Coffin equation. Crack growth in the light of the relationship first proposed by Paris is also discussed. The chapter concludes with mean stress effects (Forman Equation), scatter and statistical aspects of fatigue, i.e., Sinclair-Dolan statistical fatigue study and WeibulPs 3-parameter model.A discussion of metal fatigue without including the effects of notches is unrealistic. Chapter VI supplies information concerning stress concentrations and fatigue reduction factors, Peterson's approximate formula and short references to the Kuhn-Hardrath approach. However, no mention is General Electric Co., Schenectady, N.Y. 12345.

Objective To evaluate the efficacy of an emergency department (ED)-based lung-protective mechanical ventilation protocol for the prevention of pulmonary complications. Methods This was a quasi-experimental, before-after study that consisted of a pre-intervention period, a run-in period of approximately six months, and a prospective intervention period. The intervention was a multifaceted ED-based mechanical ventilator protocol targeting lung-protective tidal volume, appropriate setting of positive end-expiratory pressure (PEEP), rapid oxygen weaning, and head-of-bed elevation. A propensity score-matched analysis was used to evaluate the primary outcome, which was the composite incidence of acute respiratory distress syndrome and ventilator-associated conditions. Results A total of 1,192 patients in the pre-intervention group and 513 patients in the intervention group were included. Lung-protective ventilation increased by 48.4% in the intervention group. In the propensity score-matched analysis (n= 490 in each group), the primary outcome occurred in 71 patients (14.5%) in the pre-intervention group, as compared with 36 patients (7.4%) in the intervention group [adjusted OR, 0.47 (0.31–0.71)]. There was an increase in ventilator-free days (mean difference 3.7, 95% CI 2.3–5.1), ICU-free days (mean difference 2.4, (95% CI 1.0–3.7), and hospital-free days (mean difference 2.4, 95% CI 1.2–3.6) associated with the intervention. The mortality rate was 34.1% in the pre-intervention group and 19.6% in the intervention group, adjusted OR 0.47 (0.35–0.63). Conclusions Implementing a mechanical ventilator protocol in the ED is feasible, and is associated with significant improvements in the delivery of safe mechanical ventilation and clinical outcome.

Deep sedation in mechanically ventilated patients, as evaluated in a small number of qualifying heterogeneous randomized controlled trials and observational studies, was associated with increased mortality and lengths of stay. Interventions targeting early sedation depth assessment, starting in the emergency department and subsequent ICU admission, deserve further investigation and could improve outcome.