Major bleeding during negative pressure wound/V.A.C.® - therapy for postsurgical deep sternal wound infection - a critical appraisal

Negative-pressure wound therapy, commercially known as vacuum-assisted closure (V.A.C.®) therapy, has become one of the most popular (and efficacious) interim (prior to flap reconstruction) or definite methods of managing deep sternal wound infection. Complications such as profuse bleeding, which may occur during negative-pressure therapy but not necessarily due to it, are often attributed to a single factor and reported as such. However, despite the wealth of clinical experience internationally available, information regarding certain simple considerations is still lacking. Garnering information on all the factors that could possibly influence the outcome has become more difficult due to a (fortunate) decrease in the incidence of deep sternal wound infection. If more insight is to be gained from fewer clinical cases, then various potentially confounding factors should be fully disclosed before complications can be attributed to the technique itself or improvements to negative-pressure wound therapy for deep sternal wound infection can be accepted as evidence-based and the guidelines for its use adapted. The authors propose the adoption of a simple checklist in such cases

Plasma glutamine levels before cardiac surgery are related to post-surgery infections; an observational study

Abstract Background A low plasma glutamine level was found in 34% of patients after elective cardiothoracic surgery. This could be a result of the inflammation caused by surgical stress or the use of extracorporeal circulation (ECC). But it is also possible that plasma glutamine levels were already lowered before surgery and reflect an impaired metabolic state and a higher likelihood to develop complications. In the present study plasma glutamine levels were measured before and after cardiac surgery and we questioned whether there is a relation between plasma glutamine levels and duration of ECC and the occurrence of postoperative infections. Methods We performed a single-centre prospective, observational study in a closed-format, 20-bed, mixed ICU in a tertiary teaching hospital. We included consecutive patients after elective cardiac surgery with use of extracorporeal circulation. Blood samples were collected on the day prior to surgery and at admission on the ICU. The study was approved by the local Medical Ethics Committee (Regional Review Committee Patient-related Research, Medical Centre Leeuwarden, nWMO 115, April 28th 2015). Results Ninety patients were included. Pre-operative plasma glutamine level was 0.42 ± 0.10 mmol/l and post-operative 0.38 ± 0.09 mmol/l (p < 0.001). There was no relation between duration of extracorporeal circulation or aortic occlusion time and changes in plasma glutamine levels. A logistic regression analysis showed a significant correlation between the presence of a positive culture during the post-operative course and pre-operative plasma glutamine levels (p = 0.04). Conclusion Plasma glutamine levels are significantly lower just after cardiac surgery compared to pre-operative levels. We did not find a relation between the decrease in plasma glutamine levels and the duration of extracorporeal circulation or aortic clamp time. There was a correlation between pre-operative plasma glutamine levels and the presence of a positive culture after cardiac surgery. Trial registration ClinicalTrials.gov, number NCT02444780

Influence of Two Colloidal Extracorporeal Primes on Coagulation of Cardiac Surgical Patients: A Prospectively Randomized Open-Label Pilot Trial

The search for the ideal priming fluid continues as more evidence is discovered about side effects of volume expanders. With the availability of modern, balanced hydroxyethyl starch (HES) solutions with less side effects than former HES solutions, we considered to replace our gelatin- (modified gelatin) based extracorporeal circuit prime for a HES (130/.42) prime. Therefore, we studied the influence of two colloidal priming fluids on postoperative coagulation in patients undergoing cardiac surgery. The primary endpoint was to compare clot formation time between the HES group and the gelatin group with rotational thromboelastometry (ROTEM). Additionally we compared colloid osmotic pressure and fluid balance of both groups. Forty patients, undergoing elective first time coronary artery bypass grafting or single-valve surgery, were included in this prospectively randomized open-label pilot study. Laboratory data and ROTEM data were collected and analyzed for differences between the two groups. ROTEM data show significantly more prolongation in Extem clot formation time and significant more decrease in Extem alpha in the HES group. Fibtem maximum clot firmness was significantly smaller in the HES group; this was consistent with fibrinogen concentration measurement, which decreased more in the HES group than in the gelatin group and recovered more over time in the gelatin group. We found no significant difference in colloid osmotic pressure between the groups. In this trial, HES (130/.42) impairs coagulation significantly more compared with gelatin. These differences in influence on coagulation did not lead to a difference in blood loss or fluid balance, so clinical relevance could not be proven