According to current guidelines, pulmonary arterial hypertension (PAH) is diagnosed when mean pulmonary arterial pressure (Ppa) exceeds 25 mmHg at rest or 30 mmHg during exercise. Issues that remain unclear are the classification of Ppa values ,25mmHg and whether Ppa .30 mmHg during exercise is always pathological.We performed a comprehensive literature review and analysed all accessible data obtained by right heart catheter studies from healthy individuals to determine normal Ppa at rest and during exercise. Data on 1,187 individuals from 47 studies in 13 countries were included. Data were stratified for sex, age, geographical origin, body position and exercise level.Ppa at rest was 14.0¡3.3 mmHg and this value was independent of sex and ethnicity. Resting Ppa was slightly influenced by posture (supine 14.0¡3.3 mmHg, upright 13.6¡3.1 mmHg) and age (,30 yrs: 12.8¡ 3.1mmHg; 30-50 yrs: 12.9¡3.0 mmHg; o50 yrs: 14.7¡4.0 mmHg). Ppa during exercise was dependent on exercise level and age. During mild exercise, Ppa was 19.4¡4.8 mmHg in subjects aged ,50 yrs compared with 29.4¡8.4 mmHg in subjects o50 yrs (p,0.001).In conclusion, while Ppa at rest is virtually independent of age and rarely exceeds 20 mmHg, exercise Ppa is age-related and frequently exceeds 30 mmHg, especially in elderly individuals, which makes it difficult to define normal Ppa values during exercise.

clinicaltrials.gov Identifier: NCT01130181.

Aims We compared the effects of continuous subcutaneous insulin infusion (CSII) with those of multiple daily insulin (MDI) injections on glycaemic control, risk of hypoglycaemic episodes, insulin requirements and adverse events in type 1 and type 2 diabetes mellitus. Methods The electronic databases MEDLINE, EMBASE and CENTRAL were systematically searched for randomised controlled trials up to March 2007. A systematic review and meta-analysis were performed. Results Overall, 22 studies were included (17 on type 1 diabetes mellitus, two on type 2 diabetes mellitus, three on children). With regard to adults with type 1 diabetes mellitus, our meta-analysis found a between-treatment difference of −0.4% HbA 1c (six studies) in favour of CSII therapy. Available median rates of mild or overall hypoglycaemic events were comparable between the different interventions (1.9 [0.9-3.1] [CSII] vs 1.7 [1. 1-3.3] [MDI] events per patient per week). Total daily insulin requirements were lower with CSII than with MDI therapy. In patients with type 2 diabetes mellitus, CSII and MDI treatment showed no statistically significant difference for HbA 1c . The incidence of mild hypoglycaemic events was comparable between the treatment groups. In adolescents with type 1 diabetes mellitus, glycated haemoglobin and insulin requirements were significantly lower in the CSII groups; no data were available on hypoglycaemic events. The only study performed in younger children did not provide enough data for conclusive inferences. No overall conclusions were possible for severe hypoglycaemia and adverse events for any of the different patient groups due to rareness of such events, different definitions and insufficient reporting. Conclusions/interpretation CSII therapy in adults and adolescents with type 1 diabetes mellitus resulted in a greater reduction of glycated haemoglobin, in adult patients without a higher rate of hypoglycaemia. No beneficial effect of CSII therapy could be detected for patients with type 2 diabetes mellitus. Diabetologia (2008) 51:941-951

The physiological range of pulmonary vascular resistance (PVR) and total pulmonary resistance (TPR), and the impact of exercise, age and posture have been a matter of debate for many years.We performed a systematic literature review including all right heart catheterisation data where individual PVR and TPR of healthy subjects both at rest and exercise were available. Data were stratified according to age, exercise level and posture.Supine resting PVR in subjects aged ,24 yrs, 24-50 yrs, 51-69 yrs and o70 yrs was 61¡23, 69¡28, 86¡15 and 90¡39 dyn?s?cm -5 , respectively. Corresponding TPR was 165¡50, 164¡46, 226¡64 and 223¡45 dyn?s?cm -5, respectively. During moderate exercise in subjects aged f50 yrs, an 85% increase in cardiac output was associated with a 25% decrease in TPR (p,0.0001) and a 12% decrease in PVR (p,0.01). At 51-69 yrs of age there was no significant decrease in TPR and PVR. In individuals aged o70 yrs TPR even increased by 17% (p50.01), while PVR did not change significantly. At higher exercise levels, TPR decreased in all age groups. In the upright position, based on a limited number of data, resting TPR and PVR were higher than in the supine position and decreased more prominently during exercise, suggesting the release of resting pulmonary vasoconstriction.These data may form a basis to define normal PVR at rest and exercise.

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