Acute pulmonary embolism: correlation of CT pulmonary artery obstruction index with blood gas values

OBJECTIVE: The purpose of our study was to investigate the relation between the pulmonary artery obstruction index assessed with helical CT and impairment in blood gases in patients with acute pulmonary embolism. SUBJECTS AND METHODS: Helical CT pulmonary angiography was performed in 78 patients who were suspected of having acute pulmonary embolism and selected as being free of underlying cardiopulmonary disease. Findings consistent with acute pulmonary embolism were observed in 34 patients. The severity was assessed by the pulmonary artery obstruction index, defined as Sigma (n x d), where n is the number of segmental arteries occluded and d is the degree of obstruction. Spearman's rank correlation coefficients were used to assess the correlation between the index of arterial obstruction and arterial partial pressure of oxygen (Pao(2)); alveolar-arterial difference in partial pressure of oxygen (Pao(2)-Pao(2)); arterial partial pressure of carbon dioxide (Paco(2)); and arterial oxygen saturation (Sao(2)). The statistical difference of the arterial blood gas values between the two groups of patients (those with and those without pulmonary embolism) was evaluated using the Mann-Whitney U test. Blood gases were comparatively evaluated below and above different index values (from 40% to 70%) and different Paco(2) values (25, 30, and 35 mm Hg) as possible indexes of embolism severity using the same test. The level of significance was set at 95% (p = 0.05). RESULTS: The values of Pao(2), Sao(2), and Paco(2) were significantly lower (p = 0.024, p = 0.0062, and p = 0.000075, respectively) and the values of Pao(2)-Pao(2) were significantly higher (p = 0.0169) in the pulmonary embolism group than in the no-pulmonary-embolism group. A significant correlation was observed between the obstruction index and Pao(2) (r = -0.33, p = 0.05), Paco(2) (r = -0.34, p = 0.05), Pao(2)-Pao(2) (r = 0.39, p = 0.02), and Sao(2) (r = -0.35, p = 0.04). Using cutoff values for the pulmonary artery obstruction index of 40%, 50%, 60%, and 70%, we observed that Paco(2) and Pao(2)-Pao(2) differed significantly between above and below the 40% (p = 0.018 and p = 0.03), 50% (p = 0.0087 and p = 0.029), and 60% (p = 0.005 and p = 0.003) cutoffs. Pao(2) differed significantly for the cutoff values of 60% (p = 0.03) and 70% (p = 0.004). The same was observed for Sao(2) at 60% (p = 0.05) and 70% (p = 0.03). Comparisons for Paco(2) showed that a value of 30 mm Hg significantly separates levels of the pulmonary artery obstruction index (p = 0.002), with 78% sensitivity and 82% specificity indicating a pulmonary artery obstruction index greater than 50%. CONCLUSION: In patients with acute pulmonary embolism but no other underlying cardiopulmonary disease, the severity of the pulmonary arterial tree obstruction assessed using the CT obstruction index is significantly correlated to the blood gas values. The strongest correlation was observed between the index and the Pao(2)-Pao(2). Furthermore, a Paco(2) value of 30 mm Hg or less is highly suggestive of an obstruction index of more than 50% of the arterial bed.     

Meta-analysis addressing the impact of cardiovascular-acting medication on peak oxygen uptake of patients with HFpEF

Heart Failure Reviews - As our therapeutic armamentarium for HFpEF is insufficient, research has been focusing on the potential beneficial effect of existing pharmaceutical regimens on this...     

Acute acalculous cholecystitis due to infectious causes

Acute acalculous cholecystitis (AAC) is an inflammation of the gallbladder not associated with the presence of gallstones. It usually occurs in critically ill patients but it has also been implicated as a cause of cholecystitis in previously healthy individuals. In this subgroup of patients, infectious causes comprise the primary etiology. We, herein, discuss the pathophysiological mechanisms involved in AAC, focusing on the infectious causes. AAC associated with critical medical conditions is caused by bile stasis and gallbladder ischemia. Several mechanisms are reported to be involved in AAC in patients without underlying critical illness including direct invasion of the gallbladder epithelial cells, gallbladder vasculitis, obstruction of the biliary tree, and sequestration. We emphasize that multiple pathogenic mechanisms may concurrently contribute to the development of AAC in varying degrees. Awareness of the implicated pathogens is essential since it will allow a more focused examination of the histopathological specimens. In conclusion, additional research and a high degree of clinical suspicion are needed to clarify the complex spectrum of mechanisms that are involved in the pathogenesis of AAC.     

'Waste the Waist': the development of an intervention to promote changes in diet and physical activity for people with high cardiovascular risk

Objectives. To identify an evidence‐based intervention to promote changes in diet and physical activity and adapt it for a UK primary care setting for people with high cardiovascular risk. Design. A three‐stage mixed‐methods design was used to facilitate a strategic approach to programme selection and adaptation. Method. Stage 1: Criteria for scientific quality and local appropriateness were developed for the selection/adaptation of an intervention to promote lifestyle change in people of high cardiovascular risk through (1) patient interviews, (2) a literature search to extract evidence‐based criteria for behavioural interventions, and (3) stakeholder consultation. Stage 2: Potential interventions for adaptation were identified and ranked according to their performance against the criteria developed in Stage 1. Stage 3: Intervention mapping (IM) techniques were used to (1) specify the behavioural objectives that participants would need to reach in order to attain programme outcomes, and (2) adapt the selected intervention to ensure that evidence‐based strategies to target all identified behavioural objectives were included. Results. Four of 23 potential interventions identified met the 11 essential criteria agreed by a multi‐disciplinary stakeholder committee. Of these, the Greater Green Triangle programme ( Laatikainen et al., 2007 ) was ranked highest and selected for adaptation. The IM process identified 13 additional behaviour change strategies that were used to adapt the intervention for the local context. Conclusions. IM provided a useful set of techniques for the systematic adaptation of an existing lifestyle intervention to a new population and context, and facilitated transparent working processes for a multi‐disciplinary team.