Myocardial contractility and relaxation after deep hypothermic circulatory arrest in a neonatal piglet model

Cooling before circulatory arrest or ischemic arrest has been reported to influence myocardial performance in isolated neonatal hearts. The aim of the present study was to analyze indices of myocardial contractility and relaxation in an in vivo neonatal model after deep hypothermic circulatory arrest (DHCA). DHCA (18°C; DHCA group; n = 8) or mild hypothermic cardiopulmonary bypass ([MH-CPB] 32°C; MH-CPB group; n = 10) was applied in newborn piglets. After reperfusion (60 and 120 min), left ventricular dP/dt(max) increased in DHCA and MH-CPB, while-dP/dt(max) decreased slightly in DHCA and increased in MH-CPB. Nevertheless, the differences between the two groups did not reach statistical significance. In conclusion, left ventricular contractility remained stable after reperfusion following DHCA, to some degree at the expense of the diastolic function.     

Timing the initiation of renal replacement therapy for acute kidney injury in Canadian intensive care units: a multicentre observational study

Purpose

The optimal timing for starting renal replacement therapy (RRT) in patients with acute kidney injury (AKI) is unknown. Defining current practice is necessary to design interventional trials. We describe the current Canadian practice regarding the timing of RRT initiation for AKI.

Methods

An observational study of patients undergoing RRT for AKI was undertaken at 11 intensive care units (ICUs) across Canada. Data were captured on demographics, clinical and laboratory findings, indications for RRT, and timing of RRT initiation.

Results

Among 119 consecutive patients, the most common ICU admission diagnosis was sepsis/septic shock, occurring in 54%. At the time of RRT initiation, the median and interquartile range (IQR) serum creatinine level was 322 (221-432) ??mol·L^?1. The mean (SD) values for other parameters were as follows: Sequential Organ Failure Assessment (SOFA) score 13.4 (4.1), pH 7.25 (0.15), potassium 4.6 (1.0) mmol·L^?1. Also, 64% fulfilled the serum creatinine-based criterion for Acute Kidney Injury Network (AKIN) stage 3. Severity of illness, measured using Acute Physiology and Chronic Health Evaluation (APACHE II) and SOFA scores, did not correlate with AKI severity as defined by the serum creatinine-based AKIN criteria. Median (IQR) time from hospital and ICU admission to the start of RRT was 2.0 (1.0-7.0) days and 1.0 (0-2.0) day, respectively.

Conclusion

Patients admitted to an ICU who were started on RRT generally had advanced AKI, high-grade illness severity, and multiorgan dysfunction. Also, they were started on RRT shortly after hospital presentation. We describe the current state of practice in Canada regarding the initiation of RRT for AKI in critically ill patients, which can inform the designs of future interventional trials.     

Determinants for postoperative complications after laparoscopic intestinal resection for Crohn’s disease

Background  

There is lack of studies that define parameters predictive of complications following laparoscopic resection for Crohn’s disease.     

Endobronchial valve deployment in severe α‐1 antitrypsin deficiency emphysema: a case series

Introduction: Patients with end‐stage emphysema because of α‐1 antitrypsin (AAT) deficiency represent a challenging clinical management problem, and studies of volume reduction therapy to date have largely excluded these patients. We report the outcome of bronchoscopic volume reduction with the insertion of Emphasys endobronchial valves (Emphasys Medical, Redwood City, CA, USA) in six patients with end‐stage emphysema because of AAT deficiency. Case Series: Of 51 patients with end stage emphysema referred for transplantation, we studied six patients with AAT deficiency and utilized the BODE index and lung allocation score for survival estimation. Measurements and Main Results: The forced expiratory volume in 1 s improved from a median of 0.575 L to 0.905 L (P = 0.028). There was a median reduction in total lung capacity (TLC) of 0.61 L. The residual volume /TLC fell from 74.0% to 58.4%. Before treatment, four patients had a BODE index of greater than eight units, which correlates with a 4‐year survival of 18%. After treatment, two patients improved their BODE index to below seven units, which correlates with an estimated 4‐year survival of over 50%. Conclusions: The data from this case series suggest that this intervention may provide bridging therapy to subsequent transplantation for younger AAT patients with end‐stage emphysema. Please cite this paper as: Tuohy MM, Remund KF, Hilfiker R, Murphy DT, Murray JG and Egan JJ. Endobronchial valve deployment in severe α‐1 antitrypsin deficiency emphysema: a case series. Clin Respir J 2013; 7: 45–52.     

Long-term follow-up of patients with atherosclerotic renal artery disease

Atherosclerotic renal artery stenosis (ARAS) is a predictor of increased morbidity and mortality. However, whether ARAS itself accelerates the arteriosclerotic process or whether ARAS is solely the consequence of atherosclerosis is unclear. We imaged renal arteries of 1561 hypertensive patients undergoing coronary angiography and followed this cohort for 9 years (range, 2.4–15.1 years; median, 31.2 months, interquartile range, 13.4/52.9 months). All patients received aspirin, renin-angiotensin system blockade, statins, and beta blockade as indicated. One hundred seventy-one patients had ARAS >50% diameter stenosis and 126 patients an arteriosclerotic plaque (ARAP) without significant stenosis. Blood pressures were not different in ARAS, ARAP, and non-ARAS patients. After adjustment for cardiovascular risk factors by propensity scores and matched pair analysis, ARAS patients had a lower ejection fraction and more coronary artery disease (CAD) than non-ARAS patients. The same was true for brain natriuretic peptide values, troponin I, and highly sensitive C-reative protein. Over 9 years, more ARAS patients died of any cause (34% vs 23%; P < .05). The prevalence of CAD in ARAP patients was higher than in non-ARAS patients and lower than in ARAS patients. The mortality of the ARAP patients at 9 years was 37%, not different from the ARAS patients. Atherosclerotic renal artery disease appears to be a marker for the severity of atherosclerosis rather than a causative factor for atherosclerosis progression.     

Intramuscular administration of PEGylated IGF-I improves skeletal muscle regeneration after myotoxic injury

ObjectiveMusculoskeletal injuries represent a major public health problem and drugs that can improve muscle repair and restore function are needed for patients with these conditions and other related muscular pathologies. Increasing insulin-like growth factor-I (IGF-I) levels in skeletal muscle improves regeneration after myotoxic injury and while administration of IGF-I has a potential for accelerating healing after trauma, optimizing its method of delivery and obviating potential side-effects currently associated with recombinant human (rh) IGF-I, remain a hurdle.DesignWe compared the treatment efficacy of rhIGF-I with a polyethylene glycol modified IGF-I (PEG-IGF-I) analog to improve functional repair of mouse tibialis anterior muscles after myotoxic injury, testing the hypothesis that PEG-IGF-I would exert greater beneficial effects on regenerating skeletal muscles than rhIGF-I due to improved pharmacokinetic properties. We also examined the relative efficacy of systemic versus local delivery of these IGF-I variants for improving functional muscle regeneration.ResultsLocal delivery of PEG-IGF-I, but not rhIGF-I, at 4 days post-injury significantly improved early functional recovery as evident by a 27% increase in normalized force compared with saline control (P < 0.05), whereas systemic application of either IGF-I variant was not effective. The improved function with intramuscular PEG-IGF-I administration was attributed to a greater and prolonged residence within the regenerating muscles, resulting in increased Akt activation and a 13% larger fiber cross-sectional area compared with rhIGF-I (P < 0.05).ConclusionsThese data support the hypothesis that PEG-IGF-I is more efficacious than rhIGF-I in hastening early fiber regeneration and improving muscle function after injury, highlighting its therapeutic potential for muscular pathologies.