Myocardial ischemic conditioning: physiological aspects and clinical applications in cardiac surgery

Ischemia-reperfusion is a major determinant of myocardial impairment in patients undergoing cardiac surgery. The main goal of research in cardioprotection is to develop effective techniques to avoid ischemia-reperfusion lesions. Myocardial ischemic conditioning is a powerful endogenous cardioprotective phenomenon. First described in animals in 1986, myocardial ischemic conditioning consists of applying increased tolerance of the myocardium to sustained ischemia by exposing it to brief episodes of ischemia-reperfusion. Several studies have sought to demonstrate its effective cardioprotective action in humans and to understand its underlying mechanisms. Myocardial ischemic conditioning has two forms: ischemic preconditioning [IPC] when the conditioning stimulus is applied before the index ischemia and ischemic postconditioning when the conditioning stimulus is applied after it. The cardioprotective action of ischemic conditioning was reproduced by applying the ischemia-reperfusion stimulus to organs remote from the heart. This non-invasive manner of applying ischemic conditioning has led to its application in clinical settings. Clinical trials for the different forms of ischemic conditioning were mainly developed in cardiac surgery. Many studies suggest that this phenomenon can represent an interesting adjuvant to classical cardioprotection during on-pump cardiac surgery. Ischemic conditioning was also tested in interventional cardiology with interesting results. Finally, advances made in the understanding of mechanisms that underlie the cardioprotective action of ischemic conditioning have paved the way to a new form of myocardial conditioning which is pharmacological conditioning

Lower incidence of hypotension following spinal anesthesia with 6% hydroxyethyl starch preload compared to 9% saline solution in caesarean delivery

Hypotension is a common complication following spinal anesthesia for cesarean delivery. Techniques to prevent hypotension include preloading intravenous fluid. To compare the effect of two preloading regimens: 6% hydroxyethyl starch [HES] and 9‰ saline solution, to prevent hypotension after spinal anesthesia in cesarean delivery. 105 patients undergoing intrathecal anesthesia for elective cesarean delivery were randomized and allocated to receive a preload of 500 ml HES 130/0.4 [HES Group] or a preload of 1500 ml 9‰ saline solution [CR group]. Blood pressure and heart rate were recorded at baseline and after spinal anesthesia [every minute for the first 10 min, every 3 min for the next 10 min, and then every 5 min for the last 20 min]. The primary outcome was to compare the incidence of hypotension [defined as a 20% reduction in systolic arterial pressure from baseline] between the two preloading regimens. Vasopressor requirements [i.v. bolus of 6 mg ephedrine] were also compared. The incidence of hypotension was 87% in the CR group and 69% in the HES group [p= 0.028]. Ephedrine requirement, incidence of nausea, and/or vomiting and neonatal outcome did not significantly differ between the two groups. The incidence of hypotension was lower after preloading of 500 mL of HES 130/0.4 than preloading with 1500 mL of 9‰ saline solution

Ultrasound does not shorten the duration of procedure but provides a faster sensory and motor block onset in comparison to nerve stimulator in infraclavicular brachial plexus block / 대한마취과학회지

BACKGROUND: Infraclaviculr Brachial plexus (ICBP) block is useful for upper extremity surgery. The aim of this study was to compare the ultrasound (US) technique with the nerve stimulation (NS) technique in their success rates and times to perform ICBP block. METHODS: 60 patients undergoing surgery of the upper limb were randomly allocated into two groups (n = 30 per group). Group 1; US, and Group 2; NS. Procedure time (including time for initial ultrasound examination), the success rate and the onset time of sensory and motor blockade were assessed. RESULTS: The time needed to perform the ICBP block is similar in both groups (220 seconds +/- 130 in US group versus 281 +/- 134 seconds in NS group; P = 0.74). The success rate of all the nerve blocks in the US group was 100%. The success rate in the NS group was 73.3%, 76.7%, 76.7% and 100% for radial, ulnar, medial, and musculocutaneous nerve, respectively. A significantly faster onset of sensory block for the radial, ulnar, median, musculocutaneous, and the four nerves considered together were observed. The onset of motor block for the radial, ulnar, and medial nerves was faster in the US group. However, the onset of motor block for the musculocutaneous nerve and the four nerves considered together was comparable between the two groups. CONCLUSIONS: The ultrasound-guided infraclavicular brachial plexus block is a significantly efficacious method with faster onset but similar procedure time compared to the nerve stimulation technique.

[Successful use of levosimendan in a patient with cardiogenic shock complicating acute myocardial infarction]

Levosimendan is a new inodilator that improves cardiac contractility by sensitizing troponin C to calcium. This drug has proved to be effective in treating advanced congestive heart failure but has not been evaluated in cardiogenic shock. We present the case of a 54-year-old male patient treated successfully with levosimendan for cardiogenic shock following acute myocardial infarction. Treatment with dobulamine, revascularisation and intra-aortic balloon conterpulsation had first failed to improve his hemodynamic variables. Levosimendan induced a steady decline of increased pulmonary capillary wedge pressure, followed by an increase in cardiac index and mixed venous oxygen saturation. Left ventricular ejection fraction improved from 25% to 47%. Infusion of levosimendan can be used in cardiogenic shock without side effects and to improve hemodynamics and left ventricular function