A systematic review and consensus definitions for standardised end-points in perioperative medicine: pulmonary complications.

BACKGROUND: There is a need for robust, clearly defined, patient-relevant outcome measures for use in randomised trials in perioperative medicine. Our objective was to establish standard outcome measures for postoperative pulmonary complications research. METHODS: A systematic literature search was conducted using MEDLINE, Web of Science, SciELO, and the Korean Journal Database. Definitions were extracted from included manuscripts. We then conducted a three-stage Delphi consensus process to select the optimal outcome measures in terms of methodological quality and overall suitability for perioperative trials. RESULTS: From 2358 records, the full texts of 81 manuscripts were retrieved, of which 45 met the inclusion criteria. We identified three main categories of outcome measure specific to perioperative pulmonary outcomes: (i) composite outcome measures of multiple pulmonary outcomes (27 definitions); (ii) pneumonia (12 definitions); and (iii) respiratory failure (six definitions). These were rated by the group according to suitability for routine use. The majority of definitions were given a low score, and many were imprecise, difficult to apply consistently, or both, in large patient populations. A small number of highly rated definitions were identified as appropriate for widespread use. The group then recommended four outcome measures for future use, including one new definition. CONCLUSIONS: A large number of postoperative pulmonary outcome measures have been used, but most are poorly defined. Our four recommended outcome measures include a new definition of postoperative pulmonary complications, incorporating an assessment of severity. These definitions will meet the needs of most clinical effectiveness trials of treatments to improve postoperative pulmonary outcomes.

Matrix metalloproteinases contribute to endotoxin and interleukin-1beta induced vascular dysfunction.

BACKGROUND AND PURPOSE: The acute vascular inflammatory dysfunction associated with endotoxaemia may reflect an imbalance between matrix metalloproteinases (MMPs) and their natural inhibitors (TIMPs), induced by the endotoxin. This possibility was tested in rat aortic tissue. EXPERIMENTAL APPROACHES: Tone induced by phenylephrine in aortic rings was measured after exposure in vitro to ambient lipopolysaccharide (LPS) or the proinflammatory cytokine interleukin-1beta (IL-1beta) for 6h, with or without MMP inhibitors (doxycycline or GM6001). Gelatinase and MMP activities, TIMP proteins and contractility were measured in aortae taken from rats 6h after receiving LPS in vivo. KEY RESULTS: Inhibition of MMP prevented the loss of phenylephrine-induced tone in aortic rings after LPS or IL-1beta. IL-1beta also increased release of MMP-2 activity from aortic tissue. In aortae exposed in vivo to LPS, net gelatinase, MMP-9 activities and TIMP-1 protein levels were increased, whereas TIMP-4 was reduced. These aortae were hypocontractile to both phenylephrine and KCl. Hypocontractility was partially reversed by doxycycline ex vivo. CONCLUSIONS AND IMPLICATIONS: MMP inhibitors ameliorate vascular hyporeactivity induced by either LPS or IL-1beta in vitro. LPS in vivo alters the balance between MMPs and TIMPs, contributing to vascular dysfunction which is partially reversed by MMP inhibitors. Vascular MMPs are activated as a result of LPS or IL-1beta-induced stress and contribute to the hyporeactivity of blood vessels to vasoconstrictors.