G. Schaelte

A Multicenter Trial of Remote Ischemic Preconditioning for Heart Surgery

BACKGROUND Remote ischemic preconditioning (RIPC) is reported to reduce biomarkers of ischemic and reperfusion injury in patients undergoing cardiac surgery, but uncertainty about clinical outcomes remains. METHODS We conducted a prospective, double-blind, multicenter, randomized, controlled trial involving adults who were scheduled for elective cardiac surgery requiring cardiopulmonary bypass under total anesthesia with intravenous propofol. The trial compared upper-limb RIPC with a sham intervention. The primary end point was a composite of death, myocardial infarction, stroke, or acute renal failure up to the time of hospital discharge. Secondary end points included the occurrence of any individual component of the primary end point by day 90. RESULTS A total of 1403 patients underwent randomization. The full analysis set comprised 1385 patients (692 in the RIPC group and 693 in the sham-RIPC group). There was no significant between-group difference in the rate of the composite primary end point (99 patients [14.3%] in the RIPC group and 101 [14.6%] in the sham-RIPC group, P=0.89) or of any of the individual components: death (9 patients [1.3%] and 4 [0.6%], respectively; P=0.21), myocardial infarction (47 [6.8%] and 63 [9.1%], P=0.12), stroke (14 [2.0%] and 15 [2.2%], P=0.79), and acute renal failure (42 [6.1%] and 35 [5.1%], P=0.45). The results were similar in the per-protocol analysis. No treatment effect was found in any subgroup analysis. No significant differences between the RIPC group and the sham-RIPC group were seen in the level of troponin release, the duration of mechanical ventilation, the length of stay in the intensive care unit or the hospital, new onset of atrial fibrillation, and the incidence of postoperative delirium. No RIPC-related adverse events were observed. CONCLUSIONS Upper-limb RIPC performed while patients were under propofol-induced anesthesia did not show a relevant benefit among patients undergoing elective cardiac surgery. (Funded by the German Research Foundation; RIPHeart ClinicalTrials.gov number, NCT01067703.).

Postoperative kognitive Dysfunktion

The incidence of postoperative cognitive dysfunction (POCD) is often underestimated and not intuitively present by many anesthetists. POCD often occurs in the elderly but is also seen in younger patients. The incidence of POCD 1 week after non-cardiac surgery covers a span between 19-41% in patients older than 18 years. An increased POCD rate (10%) 3 months after surgery is only detected in patients older than 60 years. The occurrence of POCD is associated with an increased mortality rate, jet the etiology is mainly unknown despite enormous research efforts. The age of the patient is one of the main risk factors for the development of POCD. Data on how to avoid POCD are limited. However, the maintenance of homoeostasis is an important cornerstone of prophylaxis.

Postoperative cognitive dysfunction: Incidence and prophylaxis.

The incidence of postoperative cognitive dysfunction (POCD) is often underestimated and not intuitively present by many anesthetists. POCD often occurs in the elderly but is also seen in younger patients. The incidence of POCD 1 week after non-cardiac surgery covers a span between 19-41% in patients older than 18 years. An increased POCD rate (10%) 3 months after surgery is only detected in patients older than 60 years. The occurrence of POCD is associated with an increased mortality rate, jet the etiology is mainly unknown despite enormous research efforts. The age of the patient is one of the main risk factors for the development of POCD. Data on how to avoid POCD are limited. However, the maintenance of homoeostasis is an important cornerstone of prophylaxis.

A laboratory comparison of the performance of the buddy lite™ and enFlow™ fluid warmers

Maintenance of normothermia is crucial to avoid patient morbidity. Newly released fluid warming devices have become smaller in size, but this change might impair efficacy. We performed an evaluation of the buddy lite™ and enFlow™ fluid warmers. We measured inflow and outlet temperatures of the devices at flow rates between 25 and 100 ml.min−1 using saline at room temperature or cooled to 10 °C. At a flow rate of 25 ml.min−1, the outlet temperature of the buddy lite was significantly higher than that of the enFlow (p < 0.0001), but at flow rates of 75 and 100 ml.min−1, it was significantly lower (p < 0.0001). This pattern was the same for both room temperature and cooled saline. There was a significant drop in the temperature of saline along the length of a 1‐m outflow tube. We conclude that both devices provide effective fluid warming at a low flow rate, although the heating capability of the buddy lite is limited at high flow rates.

Air elimination capability in rapid infusion systems

Pressure infusion devices are used in clinical practice to apply large volumes of fluid over a short period of time. Although air infusion is a major complication, they have limited capability to detect and remove air during pressure infusion. In this investigation, we tested the air elimination capabilities of the Fluido® (The Surgical Company), Level 1® (Level 1 Technologies Inc.) and Ranger® (Augustine Medical GmbH) pressure infusion devices. Measurements were undertaken with a crystalloid solution during an infusion flow of 100, 200, 400 and 800 ml.min−1. Four different volumes of air (25, 50, 100 and 200 ml) were injected as boluses in one experimental setting, or infused continuously over the time needed to perfuse 2 l saline in the other setting. The perfusion fluid was collected in an airtight infusion bag and the amount of air obtained in the bag was measured. The delivered air volume was negligible and would not cause any significant air embolism in all experiments. In our experimental setting, we found, during high flow, an increased amount of uneliminated air in all used devices compared with lower perfusion flows. All tested devices had a good air elimination capability. The use of ultrasonic air detection coupled with an automatic shutoff is a significant safety improvement and can reliably prevent accidental air embolism at rapid flows.

RIPHeart (Remote Ischemic Preconditioning for Heart Surgery) Study: Myocardial Dysfunction, Postoperative Neurocognitive Dysfunction, and 1 Year Follow‐Up

Background Remote ischemic preconditioning (RIPC) has been suggested to protect against certain forms of organ injury after cardiac surgery. Previously, we reported the main results of RIPHeart (Remote Ischemic Preconditioning for Heart Surgery) Study, a multicenter trial randomizing 1403 cardiac surgery patients receiving either RIPC or sham‐RIPC. Methods and Results In this follow‐up paper, we present 1‐year follow‐up of the composite primary end point and its individual components (all‐cause mortality, myocardial infarction, stroke and acute renal failure), in a sub‐group of patients, intraoperative myocardial dysfunction assessed by transesophageal echocardiography and the incidence of postoperative neurocognitive dysfunction 5 to 7 days and 3 months after surgery. RIPC neither showed any beneficial effect on the 1‐year composite primary end point (RIPC versus sham‐RIPC 16.4% versus 16.9%) and its individual components (all‐cause mortality [3.4% versus 2.5%], myocardial infarction [7.0% versus 9.4%], stroke [2.2% versus 3.1%], acute renal failure [7.0% versus 5.7%]) nor improved intraoperative myocardial dysfunction or incidence of postoperative neurocognitive dysfunction 5 to 7 days (67 [47.5%] versus 71 [53.8%] patients) and 3 months after surgery (17 [27.9%] versus 18 [27.7%] patients), respectively. Conclusions Similar to our main study, RIPC had no effect on intraoperative myocardial dysfunction, neurocognitive function and long‐term outcome in cardiac surgery patients undergoing propofol anesthesia. Clinical Trial Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT01067703.

Postoperative kognitive Dysfunktion@@@Postoperative cognitive dysfunction: Inzidenz und Prophylaxe@@@Incidence and prophylaxis

The incidence of postoperative cognitive dysfunction (POCD) is often underestimated and not intuitively present by many anesthetists. POCD often occurs in the elderly but is also seen in younger patients. The incidence of POCD 1 week after non-cardiac surgery covers a span between 19-41% in patients older than 18 years. An increased POCD rate (10%) 3 months after surgery is only detected in patients older than 60 years. The occurrence of POCD is associated with an increased mortality rate, jet the etiology is mainly unknown despite enormous research efforts. The age of the patient is one of the main risk factors for the development of POCD. Data on how to avoid POCD are limited. However, the maintenance of homoeostasis is an important cornerstone of prophylaxis.