Standard Crystalloid Solution Research Articles

A novel miniaturized roller pump circuit for simulation of extracorporeal circulation.

Extracorporeal circulation induces pronounced effects on haemostasis and rheology. To study these, an ex vivo simulation model is an attractive alternative but often requires large amounts of blood. We sought to create a miniaturized roller pump circuit requiring minimal amounts of blood and to test if the circuit could be used to compare coagulation, platelet function and blood rheology between a dextran-based and a crystalloid-based priming solution. A miniaturized roller pump circuit requiring only 27 ml of blood was created. Blood samples from 8 cardiac surgery patients were mixed with either a dextran-based or a crystalloid-based solution and circulated for 60 min. Coagulation was assessed by rotational thromboelastometry, and platelet function by impedance aggregometry and flow cytometry, before and at 5 and 60 min of circulation. A time-dependent impairment of coagulation was observed in both groups. Maximum clot firmness was lower with dextran-based than with crystalloid-based priming at 5 min (HEPTEM 37 ± 4 vs 43 ± 4 mm, P < 0.001; EXTEM 37 ± 4 vs 43 ± 4 mm, P < 0.001; FIBTEM 3 ± 2 vs 9 ± 2 mm, P < 0.001) and at 60 min (HEPTEM 29 ± 9 vs 38 ± 5 mm, P < 0.001; EXTEM 30 ± 7 vs 39 ± 5 mm, P < 0.001; FIBTEM 3 ± 2 vs 8 ± 3 mm, P = 0.002). The EXTEM clotting time was longer with dextran-based solution at 5 (109 ± 19 vs 63 ± 7 sec, P < 0.001) and at 60 min (176 ± 72 vs 73 ± 7 sec, P = 0.004). The novel miniaturized roller pump circuit can be used to mimic extracorporeal circulation for selected research questions. Dextran-based priming caused a significant impairment in haemostasis compared with a standard crystalloid solution.

Myocardial protection against global ischemia with Krebs-Henseleit buffer-based cardioplegic solution

BackgroundThe Krebs-Henseleit buffer is the best perfusion solution for isolated mammalian hearts. We hypothesized that a Krebs-Henseleit buffer-based cardioplegic solution might provide better myocardial protection than well-known crystalloid cardioplegic solutions because of its optimal electrolyte and glucose levels, presence of buffer systems, and mild hyperosmolarity.MethodsIsolated Langendorff-perfused rat hearts were subjected to either global ischemia without cardioplegia (controls) or cardioplegic arrest for either 60 or 180 min, followed by 120 min of reperfusion. The modified Krebs-Henseleit buffer-based cardioplegic solution (mKHB) and St. Thomas’ Hospital solution No. 2 (STH2) were studied. During global ischemia, the temperatures of the heart and the cardioplegic solutions were maintained at either 37°C (60 min of ischemia) or 22°C (moderate hypothermia, 180 min of ischemia). Hemodynamic parameters were registered throughout the experiments. The infarct size was determined through histochemical examination.ResultsCardioplegia with the mKHB solution at moderate hypothermia resulted in a minimal infarct size (5 ± 3%) compared to that in the controls and STH2 solution (35 ± 7% and 19 ± 9%, respectively; P < 0.001, for both groups vs. the mKHB group). In contrast to the control and STH2-treated hearts, no ischemic contracture was registered in the mKHB group during the 180-min global ischemia. At normothermia, the infarct sizes were 4 ± 3%, 72 ± 6%, and 70 ± 12% in the mKHB, controls, and STH2 groups, respectively (P < 0.0001). In addition, cardioplegia with mKHB at normothermia prevented ischemic contracture and improved the postischemic functional recovery of the left ventricle (P < 0.001, vs. STH2).ConclusionsThe data suggest that the Krebs-Henseleit buffer-based cardioplegic might be superior to the standard crystalloid solution (STH2).

A combination of metabolic strategies plus cardiopulmonary bypass improves short-term resuscitation from prolonged lethal cardiac arrest

Background The metabolic or late phase of cardiac arrest is highly lethal. Emergency cardiopulmonary bypass (ECPB) can resuscitate many patients even after prolonged cardiac arrest and provides immediate vascular access for correction of metabolic derangement during the reperfusion process. We developed a rodent model of ECPB resuscitation which showed the superiority of ECPB over conventional CPR, especially when combined with hypothermia. For this study we examined a metabolic strategy against ischemia–reperfusion injury (MS-IR) that included: leukoreduction, low Ca 2+, Mg 2+, buffered pH, red blood cells and a colloid. We tested whether ECPB plus MS-IR and/or hypothermia improves short-term hemodynamic outcomes compared to a standard ECPB reperfusate. Methods Using a 2×2 factorial design we tested ECPB with (a) MS-IR versus a standard crystalloid solution; and (b) hypothermia versus normothermia in our rat model. The four reperfusion strategies included: (1) MS-IR plus hypothermia, (2) MS-IR with normothermia, (3) standard plasma-lyte (STD) reperfusate plus hypothermia, or (4) STD plus normothermia. Animals underwent 12 min of untreated asphyxial arrest and were resuscitated with ECPB and one of the four strategies for 30 min. Thereafter, ECPB was discontinued and ventilatory support was provided for 3 hours, while hemodynamic, perfusion and other metrics were serially measured. Results All rats achieved ROSC with ECPB. Significant differences between the groups emerged after 3 hrs: the best outcomes were in animals with MS-IR plus hypothermia (lactate: 1.1 ± 0.1 mmol/L; MAP: 83 ± 4 mm Hg, seizures: 0/10), while the worst outcomes were with STD and normothermia (lactate: 8.9 ± 1.4 mmol/L, MAP: 36 ± 4 mm Hg, seizures: 7/10, p < 0.001). The outcomes of the other two groups (MS-IR only; hypothermia only) were intermediate. MS-IR and hypothermia improved outcome in an additive fashion. Conclusions While most human ECPB is applied with a normothermic crystalloid priming solution, we observed that in rodents the addition of MS-IR plus hypothermia resulted in considerable short-term benefit after prolonged arrest. Future long-term and translational survival studies are warranted to optimize ECPB resuscitation methods.

Clinical trial of retrograde warm blood reperfusion versus standard cold topical irrigation of transplanted hearts

A prospective, randomized clinical study involving 34 patients undergoing heart transplantation compared myocardial preservation of donor hearts maintained with continuous reperfusion with retrograde warm blood cardioplegia during surgical implantation versus the standard cold topical irrigation. Hearts in both groups were arrested with a standard crystalloid solution and maintained in a cold saline solution during transportation. In the retrograde group, cardioplegia was administered through a catheter in the coronary sinus during surgical implantation. An average of 471 +/- 30 mL of hyperkalemic crystalloid solution diluted 1:4 in warm blood from the oxygenator was infused. In the standard group, the heart was kept cold by topical irrigation of cold saline solution and was reperfused only when the ascending aorta was unclamped. Preoperative characteristics of donors and recipients were similar in the two cohorts. Ischemic time average 139 +/- 12 minutes in the retrograde group compared with 130 +/- 11 minutes in the standard group (p = 0.57). Cardiopulmonary bypass time averaged 89 +/- 4 minutes in the retrograde group and 110 +/- 12 minutes in the standard group (p = 0.12). Defibrillation at reperfusion was performed in 4 patients (4/17, 24%) in the retrograde group and 12 patients (12/18, 67%) in the standard group (p = 0.01). There were no deaths in the retrograde group (0/17), whereas in the standard group, 3 patients (3/17) died of early graft failure (p = 0.11). Four early graft failures occurred in the standard group (p = 0.06). Two patients (2/17, 12%) were weaned from bypass with ventricular assist devices in the standard group. The number of subendocardial necrotic cells in the first two weekly endomyocardial biopsy specimens averaged 2.7 +/- 0.8 cells/mm2 in the retrograde group and 5.9 +/- 2.4 cells/mm2 in the standard group (p = 0.12). Retrograde warm blood reperfusion appears to improve the initial recovery of transplanted hearts. The technique is easy to use and may be a useful approach to graft protection during surgical implantation.

Myocardial protection by blood cardioplegia and warm reperfusion in heart transplantation

We describe the technique of blood cardioplegia delivery as we routinely use it in clinical heart transplantation. This technique needs a specific circuit. Perfusion of a first dose of blood cardioplegia is immediately started on the arrival of the graft in the operating room. Cardiac reperfusion of a half-dose of blood solution without potassium is performed each 20 minutes. Myocardial warm reperfusion is started at the end of the aortic suture. This technique of blood cardioplegia and warm reperfusion during heart transplantation provided an improvement in heart preservation when compared with standard crystalloid solution.

Concentrated albumin infusion as an aid to postoperative recovery after pelvic exenteration

Twenty-eight patients underwent pelvic exenterations for gynecologic malignancies between June 1986 and June 1989. The postoperative fluid and electrolytes were managed by one of two regimens. One group of 10 patients was given concentrated 25% albumin infusion for the first 16 hr after surgery in addition to maintenance intravenous crystalloid solution according to ideal body weight. The second group of 18 patients received only a standard crystalloid solution. The albumin infusion group was found to have a more stable postoperative course as evidenced by less fluid boluses ( P < 0.01), fewer electrolyte bolus requirements ( P < 0.01), and easier management of blood pressure and urine output. There was a 50% decrease in total fluid requirement, a higher mean right atrial pressure ( P < 0.05), and a lower maintenance intravenous fluid rate ( P < 0.01). As a consequence, central hyperalimentation was started earlier ( P < 0.01) and the albumin infusion group left the Intensive Care Unit sooner than the non-albumin infusion group. There was not a single instance of clinical fluid overload with this slow infusion technique. Thus, concentrated albumin infusion was beneficial in the acute fluid management of these difficult patients.