Critical care : the official journal of the Critical Care Forum
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Comparative Study
Continuous control of endotracheal cuff pressure and tracheal wall damage: a randomized controlled animal study.
Intubation is frequently performed in intensive care unit patients. Overinflation of the endotracheal tube cuff is a risk factor for tracheal ischemia and subsequent complications. Despite manual control of the cuff pressure, overinflation of the endotracheal cuff is common in intensive care unit patients. We hypothesized that efficient continuous control of the endotracheal cuff pressure using a pneumatic device would reduce tracheal ischemic lesions in piglets ventilated for 48 hours through a high-volume, low-pressure endotracheal tube. ⋯ The pneumatic device provided effective continuous control of high-volume, low-pressure endotracheal cuff pressure in piglets mechanically ventilated for 48 hours. In the present model, however, no significant difference was found in tracheal mucosal lesions of animals with or without a pneumatic device. Further studies are needed to determine the impact of continuous control of cuff pressure over a longer duration of mechanical ventilation.
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Assessment of left ventricular diastolic function in the critically ill patient remains a difficult issue in clinical practice. Combined use of routine transmitral and pulmonary venous Doppler patterns in conjunction with tissue Doppler imaging have been claimed to allow bedside diagnosis of diastolic dysfunction. Although in the previous issue of Critical Care it was clearly demonstrated there might be a difference in load dependency of the early myocardial tissue Doppler velocity between lateral and septal placed sample volume, there remain still several unanswered questions, particularly with respect to the preload dependency of these indices.
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Terror attacks in Southeast Asia were almost nonexistent until the 2002 Bali bomb blast, considered the deadliest attack in Indonesian history. Further attacks in 2003 (Jakarta), 2004 (Jakarta), and 2005 (Bali) have turned terrorist attacks into an ever-present reality. ⋯ The changing nature of terror attacks mandates continued vigilance and disaster preparedness. The multidimensional burns patient, complicated by other injuries, is likely to become increasingly common. A burns disaster plan with emphasis on effective command, control, and communication as well as organisation of health care personnel following a 'team concept' will do much to ensure that the sudden onset of a crisis situation at an unexpected time does not overwhelm hospital manpower and resources.
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One potential mechanism of ventilator-induced lung injury (VILI) is due to shear stresses associated with alveolar instability (recruitment/derecruitment). It has been postulated that the optimal combination of tidal volume (Vt) and positive end-expiratory pressure (PEEP) stabilizes alveoli, thus diminishing recruitment/derecruitment and reducing VILI. In this study we directly visualized the effect of Vt and PEEP on alveolar mechanics and correlated alveolar stability with lung injury. ⋯ A ventilatory strategy employing high Vt and low PEEP causes alveolar instability, and to our knowledge this is the first study to confirm this finding by direct visualization. These studies demonstrate that low Vt and high PEEP work synergistically to stabilize alveoli, although increased PEEP is more effective at stabilizing alveoli than reduced Vt. In this animal model of ARDS, alveolar instability results in lung injury (VILI) with minimal changes in plasma and bronchoalveolar lavage cytokines and proteases. This suggests that the mechanism of lung injury in the high Vt/low PEEP group was mechanical, not inflammatory in nature.
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In acute lung injury (ALI), elevation of procollagen type III (PC III) occurs early and has an adverse impact on outcome. We examined whether different high-inflation strategies of mechanical ventilation (MV) in oleic acid (OA) ALI alter regional expression of PC III. ⋯ PC III expression is higher in nondependent regions and in ventilatory strategies that caused overdistension. This response was partially attenuated by prone positioning.