Application of a mechanical ventilation weaning protocol in a coronary unit

Abstract

Objectives To characterize an experimental model of pulmonary embolism by studying hemodynamics, lung mechanics and histopathologic derangements caused by pulmonary microembolism in pigs. To identify lung alterations after embolism that may be similar to those evidenced in pulmonary inflammatory conditions. Materials and methods Ten Large White pigs (weight 35-42 kg) were instrumented with arterial and pulmonary catheters, and pulmonary embolism was induced in five pigs by injection of polystyrene microspheres (diameter ~300 µM), in order to obtain a pulmonary mean arterial pressure of twice the baseline value. Five other animals injected with saline served as controls. Hemodynamic and respiratory data were collected and pressure x volume curves of the respiratory system were performed by a quasi-static low flow method. Animals were followed for 12 hours, and after death lung fragments were dissected and sent to pathology. Results Pulmonary embolism induced a significant reduction in stroke volume (71 ± 18 ml/min/bpm pre vs 36 ± 9 ml/min/bpm post, P < 0.05), an increase in pulmonary mean arterial pressure (27 ± 4 mmHg pre vs 39 ± 6 mmHg post, P < 0.05) and pulmonary vascular resistance (193 ± 122 mmHg/l/min pre vs 451 ± 149 mmHg/l/min post, P < 0.05). Respiratory dysfunction was evidenced by significant reductions in the PaO 2 /FiO 2 ratio (480 ± 50 pre vs 159 ± 55 post, P < 0.05), the dynamic lung compliance (27 ± 6 ml/cmH 2 O pre vs 19 ± 5 ml/cmH 2 O post, P < 0.05), the increase in dead space ventilation (20 ± 4 pre vs 47 ± 20 post, P < 0.05) and, the shift of pressure x volume curves to the right, with reduction in pulmonary hysteresis. Pathology depicted inflammatory neutrophil infiltrates, alveolar edema, collapse and hemorrhagic infarctions. Conclusion This model of embolism is associated with cardiovascular dysfunction, as well as respiratory injury characterized by a decrease in oxygenation, lung compliance and hysteresis. Pathology findings were similar to those verified in inflammatory pulmonary injury conditions. This model may be useful to study pathophysiology, as well as pharmacologic and ventilatory interventions useful to treat pulmonary embolism. P6 Hemodynamic and metabolic features of a porcine systemic low flow state model

BTS/ICS guideline for the ventilatory management of acute hypercapnic respiratory failure in adults

“…There is also marked variation in the weaning methods and protocols between the studies reported. A European study reported that a weaning protocol did not reduce ventilation time 246. Computer-automated weaning, in which adjustment in pressure settings occurs in response to changes in patient parameters, has been compared to professional-led weaning.…”

Evaluation of a clinical pathway for sedation and analgesia of mechanically ventilated patients in a cardiac intensive care unit (CICU): The Brigham and Women’s Hospital Levine CICU sedation pathways

“…Perhaps most importantly, despite the fact that nearly all patients in both populations were admitted with primary cardiac rather than non-cardiac issues, our study found no evidence to support the notion that this specialized population should be managed differently from non-cardiac populations with respect to analgesia and sedation. 5,11 Further research is necessary to probe these potential benefits and identify sub-populations that may require further specialized sedation strategies, such as patients requiring percutaneously placed mechanical circulatory support.…”

A systematic review of nurse‐led weaning protocol for mechanically ventilated adult patients

“…() described PBW that included spontaneous breathing trials with CPAP; for patients who satisfied the eligibility criteria for weaning, the duration of SBTs ranged from 30 to 120 min through a ventilator circuit. This is in accordance with six other studies (Ely et al ., , Kollef et al ., ; Marelich et al ., ; Namen et al ., ; Krishnan et al ., ; Piotto et al ., ). However, in Roh et al .…”