Intravascular versus surface cooling speed and stability after cardiopulmonary resuscitation.

BACKGROUND AND OBJECTIVE: Mild therapeutic hypothermia (MTH) is used to limit neurological injury and improve survival after cardiac arrest (CA) and cardiopulmonary resuscitation, but the optimal mode of cooling is controversial. We therefore compared the effectiveness of MTH using invasive intravascular or non-invasive surface cooling with temperature feedback control. METHODS: This retrospective study in post-CA patients studied the effects of intravascular cooling (CoolGard, Zoll, n=97), applied on the intensive care unit (ICU) in one university hospital compared with those of surface cooling (Medi-Therm, Gaymar, n=76) applied in another university hospital. RESULTS: Time to reach target temperature and cooling speeds did not differ between groups. During the maintenance phase, mean core temperature was 33.1°C (range 32.7-33.7°C) versus 32.5°C (range 31.7-33.4°C) at targets of 33.0 and 32.5°C in intravascularly versus surface cooled patients, respectively. The variation coefficient for temperature during maintenance was higher in the surface than the intravascular cooling group (mean 0.85% vs 0.35%, p<0.0001). ICU survival was 60% and 50% in the intravascularly and surface cooled groups, respectively (NS). Lower age (OR 0.95; 95% CI 0.93 to 0.98; p<0.0001), ventricular fibrillation/ventricular tachycardia as presenting rhythm (OR 7.6; 95% CI 1.8 to 8.9; p<0.0001) and lower mean temperature during the maintenance phase (OR 0.52; 95% CI 0.25 to 1.08; p=0.081) might be independent determinants of ICU survival, while cooling technique and temperature variability did not contribute. CONCLUSIONS: In post-CA patients, intravascular cooling systems result in equal cooling speed, but less variation in temperature during the maintenance phase, as surface cooling. This may not affect the outcome.

Impact of the definition of renal dysfunction on EuroSCORE performance.

AIM: Renal dysfunction is an important variable in the EuroSCORE (European System for Cardiac Operative Risk Evaluation) model and is currently defined as creatinine >200 mmol/L. The aim of this study was to examine whether using other definitions of renal dysfunction could improve the predictive ability of the EuroSCORE. METHODS: Between January 2004 and January 2006, 1 205 patients underwent cardiac surgery. Their preoperative glomerular filtration rate and EuroSCORE were calculated. Four recalibrated EuroSCORE models were constructed using 1) creatinine as a binary variable; 2) creatinine as a continuous variable; 3) glomerular filtration rate as a categorical variable; or 4) glomerular filtration rate as a continuous variable. The predictive ability of these models was assessed using receiver operating characteristic curve analysis. RESULTS: Hospital mortality was 4% (N.=47). Receiver operating characteristic curve values were: 0.78 for the original EuroSCORE, 0.80 for the recalibrated binary creatinine model, 0.83 for the continuous creatinine model, 0.83 for the categorical glomerular filtration rate model, and 0.82 for the continuous glomerular filtration rate model. CONCLUSIONS: The use of creatinine as a continuous variable or glomerular filtration rate as a categorical or continuous variable improves the predictive accuracy of the EuroSCORE model for hospital mortality. Given the increasing incidence of preoperative renal dysfunction and its impact on hospital mortality, future risk stratification models should include continuous creatinine or glomerular filtration rate rather than creatinine as a binary variable.

The open lung concept: effects on right ventricular afterload after cardiac surgery.

BACKGROUND: The open lung concept (OLC) is a method of ventilation intended to maintain end-expiratory lung volume by increased airway pressure. Since this could increase right ventricular afterload, we studied the effect of this method on right ventricular afterload in patients after cardiac surgery. METHODS: We studied 24 stable patients after coronary artery surgery and/or valve surgery with cardiopulmonary bypass. Patients were randomly assigned to OLC or conventional mechanical ventilation (CMV). In the OLC group, recruitment manoeuvres were applied until Pa(o(2))/FI(O(2)) was greater than 50 kPa (reflecting an open lung). This value was maintained by sufficient positive airway pressure. In the CMV group, volume-controlled ventilation was used with a PEEP of 5 cm H(2)O. Cardiac index, right ventricular preload, contractility and afterload were measured with a pulmonary artery thermodilution catheter during the 3-h observation period. Blood gases were monitored continuously. RESULTS: To achieve Pa(O(2))/Fl(O(2)) > 50 kPa, 5.3 (3) (mean, SD) recruitment attempts were performed with a peak pressure of 45.5 (2) cm H(2)O. To keep the lung open, PEEP of 17.0 (3) cm H(2)O was required. Compared with baseline, pulmonary vascular resistance and right ventricular ejection fraction did not change significantly during the observation period in either group. CONCLUSION: No evidence was found that ventilation according to the OLC affects right ventricular afterload.

Acute effects of etidronate on glucocorticoid-induced bone degradation.

OBJECTIVES: To study the acute short-term effects on the biochemical parameters of calcium and bone homeostasis in post-menopausal women treated with a high dose of prednisone alone or with additional etidronate, before and during 5 days of treatment. METHODS: Serum calcium, phosphorus, creatinine, alkaline phosphatase activity, osteocalcin, carboxy-terminal propeptide of type I procollagen (PICP), cross-linked carboxy-terminal telopeptide of type I collagen (ICTP), parathyroid hormone (PTH), 25-hydroxyvitamin D and urinary excretion of calcium over 24 h were measured before and during 5 days of treatment in 14 post-menopausal women treated with a high dose of prednisone (60 mg/day) alone (group A) or combined with cyclical etidronate (group B). RESULTS: Significant differences from baseline were found in osteocalcin and urinary excretion of calcium in both groups and for ICTP in group B. Significant differences between groups were calculated at day 5 of the study for osteocalcin, ICTP and 24 h urine calcium excretion (P < 0.01). Urinary excretion of calcium over 24 h increased in group A (+14.7%; P < 0.05) and decreased in group B (-22.1%; P < 0.01). Osteocalcin levels decreased in group A (- 38.1%) and increased in group B (+27.4%; both P < 0.01). ICTP decreased only in group B (-19.4%; P < 0.01). CONCLUSIONS: The results are consistent with the fact that etidronate is acutely able to prevent bone resorption due to corticosteroids. The increase in osteocalcin in the etidronate-treated group is a new feature. A direct or indirect (PTH, 1,25 vitamin D?) stimulatory effect of etidronate on the osteoblast cannot be excluded.

The effects of inhaled glucocorticoids on bone mass and biochemical markers of bone homeostasis: a 1-year study of beclomethasone versus budesonide.

Bone mass and biochemical bone markers were prospectively studied in 33 patients with chronic obstructive pulmonary disease treated for 1 year with inhaled beclomethasone 200 micrograms/q.i.d. (group A, 8 men and 4 women), inhaled budesonide 200 micrograms/q.i.d. (group B, 6 men and 5 women), or not requiring steroids (group C, 6 men and 4 women). Both inhaled corticosteroids decreased serum concentrations of the osteoblastic markers, osteocalcin and carboxy-terminal propeptide of type I collagen (PICP). The osteoclastic marker cross-linked carboxy-terminal telopeptide of type I collagen (ICTP) increased significantly more in patients on beclomethasone than in those on budesonide. The decrease in bone mineral density was more pronounced in patients treated with beclomethasone (1.1% in the spine 1.7% in the hip P < 0.05) compared to those treated with budesonide (0.6% in both spine and hip) or in the control group. Inhaled corticosteroids affect biochemical bone markers and bone mineral density, but there is a different effect for the two corticosteroids evaluated in the present study.