Effects of blood and crystalloid cardioplegia on cardiac function at organ and cellular levels during hypothermic cardiac arrest

Feasibility of electroacupuncture at Baihui (GV20) and Zusanli (ST36) on survival with a favorable neurological outcome in patients with postcardiac arrest syndrome after in-hospital cardiac arrest: study protocol for a pilot randomized controlled trial

BACKGROUND

At present, even the first-line medication epinephrine still shows no evidence of a favourable neurological outcome in patients with sudden cardiac arrest (SCA). The high mortality of patients with postcardiac arrest syndrome (PCAS) can be attributed to brain injury, myocardial dysfunction, systemic ischaemia/reperfusion response, and persistent precipitating pathology. Targeted temperature management, the only clinically proven method in the treatment of PCAS, is still associated with a series of problems that have not been completely resolved. Acupuncture is a crucial therapy in traditional Chinese medicine. On the basis of the results of previous studies, we hypothesize that electroacupuncture (EA) might provide therapeutic benefits in the treatment of PCAS. This study will explore the feasibility of EA on SCA patients.

METHODS

This is a prospective pilot, randomized controlled clinical trial. Eligible patients with PCAS after in-hospital cardiac arrest (IHCA) admitted to our department will be randomly allocated to the control group or the EA group. Both groups will receive standard therapy according to American Heart Association guidelines for cardiopulmonary resuscitation. However, the EA group will also receive acupuncture at the Baihui acupoint (GV20) and Zusanli acupoint (ST36) with EA stimulation for 30 min using a dense-dispersed wave at frequencies of 20 and 100 Hz, a current intensity of less than 10 mA, and a pulse width of 0.5 ms. EA treatment will be administered for up to 14 days (until either discharge or death). The primary endpoint is survival with a favourable neurological outcome. The secondary endpoints are neurological scores, cardiac function parameters, and other clinical parameters, including Sequential Organ Failure Assessment (SOFA) scores and Acute Physiology and Chronic Health Evaluation (APACHE) II scores, on days 0 to 28.

DISCUSSION

This study will provide crucial clinical evidence on the efficacy of EA in PCAS when used as an adjunctive treatment with AHA standard therapy.

TRIAL REGISTRATION

chictr.org.cn : ChiCTR2000040040. Registered on 19 November 2020. Retrospectively registered. http://www.chictr.org.cn/ .

Comparison Between Blood and Crystalloid Cardioplegia in Patients with Left Ventricular Dysfunction Undergoing Coronary Surgery

This study was done to compare the protective effect of blood and crystalloid cardioplegia in patients with left ventricular dysfunction undergoing coronary artery bypass grafting (CABG). Sixty consecutive patients with left ventricular ejection fraction < 35 % scheduled for CABG with the use of cardiopulmonary bypass without additional procedures were randomly divided into two groups. In the first group we used cold blood cardioplegia, in the second group cold crystalloid cardioplegia, both delivered only ortogradly. We measured hemodynamic data in early hours after operation, enzyme release and we collected other clinical data which could be influenced by perioperative myocardial protection. There was no death in either group. We also didn’t find any significant difference in incidence of perioperative myocardial infarction, arrhytmias and use of intraaortic balloon pumping between both groups. In an early hours after operation in the group with blood cardioplegia we found significantly better hemodynamic data (LVSWI, RVSWI) and significantly lower enzyme release. We conclude, that cold blood cardioplegia shows superior perioperative myocardial protection resulting in earlier restoration of myocardial function. This difference could be important in patients with high degree of left ventricular dysfunction.

Pinacidil improves contractile function and intracellular calcium handling in isolated cardiac myocytes exposed to simulated cardioplegic arrest

BACKGROUND

We examined the effects of pinacidil on contractile function and intracellular calcium in isolated rat cardiomyocytes exposed to cardioplegic solution.

METHODS

Rat myocytes were incubated at 24 degrees C for 2 hours in cardioplegic solution with or without pinacidil (50 micromol/L), then they were perfused with Krebs-Henseleit solution with a gas phase of 95% O2/5% CO2 at the same temperature. Contraction and intracellular calcium transients were then measured by video tracking and spectrofluorometry.

RESULTS

During 20 minutes of perfusion after 2 hours in cardioplegic solution with pinacidil, (1) the recovery of contractile function was significantly increased in terms of both amplitude of contraction (98.30% +/- 9.90% versus 81.00% +/- 11.25%; p < 0.05) and peak velocity of cell shortening (100.90% +/- 13.79% versus 76.89% +/- 18.14%; p < 0.01) when compared with myocytes in cardioplegic solution without pinacidil; (2) the amplitudes of the intracellular calcium transients evoked by electrical stimulation and caffeine (10 mmol/L) increased by 23.31% to approximately 40.72% and 61.73%, respectively, compared with those in cardioplegic solution without pinacidil; and (3) the decay time of the caffeine-induced intracellular calcium transient decreased by 36.64% +/- 15.10% relative to that measured in cardioplegic solution without pinacidil. The effects induced by supplementing the cardioplegic solution with pinacidil were diminished in the presence of glibenclamide (10 micromol/L).

CONCLUSIONS

Addition of the adenosine triphosphate-sensitive potassium-channel opener, pinacidil, to a high potassium cardioplegic solution improves recovery of contractile properties and cytosolic calcium in isolated rat cardiac myocytes.

Circulatory arrest under hypothermic anesthesia using abdominal cavity cooling

The purpose of this study was to investigate the potential for circulatory arrest during surgery under systemic hypothermic anesthesia, using the abdominal cavity cooling method. Eighteen beagles, each weighing 10.5 +/- 2.3 kg, were cooled by filling the abdominal cavity with crushed ice. Just after the esophageal temperature reached 30 degrees C, the heart was exposed, and a left-heart bypass from the left atrium to the aortic root was created. At 20-23 degrees C, the heart was arrested by infusing cooled Young's solution into the aortic root. After a period of cardiac arrest, resuscitation and rewarming were initiated simultaneously. Throughout these procedures, an electrocardiogram (ECG) and the arterial blood pressure (ABP) were monitored continuously. Hematocrit (Ht), total protein (TP), and arterial blood pH and gases were measured every 30 min. The recoveries after surgery were divided into three types as follows, 1) recovery without any complications-11 dogs, 2) not extubated with spontaneous breathing-4 dogs, 3) no reappearance of heart beat-3 dogs. PaO2 during resuscitation was significantly higher in dogs which recovered completely than in the rest of the dogs. These results suggest that hypothermia induced by the abdominal cavity cooling method could be useful for organ-protection during open-heart surgery, and that successful recovery may be attained through protection of the lung as well as the myocardium.

Beneficial effects of methionine on myocardial hemodynamic and cellular functions in hemorrhagic shock

Hypochlorous acid (HOCl), produced by activated polymorphonuclear (PMN) leukocytes, has been reported to depress cardiac function and contractility. Various mechanisms exist for activation of PMN leukocytes during hemorrhagic shock and reperfusion. In order to determine the role of HOCl in hemorrhagic shock and reinfusion, the authors studied the effects of shock and reinfusion on the cardiac function, contractility, blood lactate, blood gases, and creatine kinase (CK) and MB fraction of CK (MBCK) with and without methionine (quencher of HOCl) in anesthetized dogs. Dogs were divided into two groups: Group I, hemorrhagic shock (two hours) and reinfusion (two hours): Group II, hemorrhagic shock and reinfusion with methionine treatment. Cardiac index, mean arterial pressure, and index of cardiac contractility were similar in the two groups during shock. Postinfusion recovery of cardiac function and contractility was better in group II. Increases in blood lactate were similar in the two groups during shock. The rate of return of blood lactate to preshock values after reinfusion was greater in group II. The increases in serum CK and MBCK of the two groups during shock were similar but not significant. Following reinfusion the levels of these enzymes increased significantly, but the increases in group II were less. These results suggest that HOCl produced by activated PMN leukocytes may play a role in cardiac damage during hemorrhagic shock and reinfusion. Methionine may have beneficial effects in the hemodynamic and metabolic recovery and may reduce cellular damage during hemorrhage shock and reinfusion.

Effects of diltiazem on the functional recovery of the myocardium at organ and cellular level during prolonged hypothermic ischemic cardiac arrest

The effectiveness of diltiazem on the functional recovery of the heart, calcium (Ca++) uptake and binding, Ca++ ATPase of cardiac sarcoplasmic reticulum (SR), and MB fraction of creatine kinase (MBCK) of coronary sinus blood was investigated after one and a half hours of reperfusion following three hours of ischemic cardiac arrest. The dogs were divided into three groups: group I, sham bypass; group II, cold crystalloid cardioplegia; and group III, cold crystalloid cardioplegia with diltiazem. There was a decrease in aortic pressures left ventricular pressure development (dp/dt), left ventricular work index (LVWI), total systemic vascular resistance (TSVR), and left ventricular systolic pressure (LVSP) in the sham bypass group. There was a decrease in cardiac index (CI), LVWI, and mean right atrial pressure (mRAP) and an increase in TSVR and pulmonary vascular resistance (PVR) in group II as compared with group I. Although there was a tendency for a decrease in the indices of myocardial contractility in group II, they were not significantly different from those in group I. The indices of myocardial contractility, CI, and LVWI in group III were slightly higher than in group II, but they were not significantly different from each other. The values for calcium uptake by SR in groups II and III were similar but significantly lower than those in group I. Calcium binding in group III was significantly lower than that in group I. Calcium ATPase of SR in the three groups were similar. Although MBCK increased in all the groups, the increases were not significantly different among the three groups. The results of this study indicate that cold crystalloid cardioplegia with diltiazem was not better than cold crystalloid alone in preserving the cardiac contractility and cellular function during prolonged ischemic cardiac arrest. However, the cardiac function in terms of cardiac index was better preserved with diltiazem.