Remote ischemic preconditioning does not prevent acute mountain sickness after rapid ascent to 3,450 m.

Remote ischemic preconditioning (RIPC) has been shown to protect remote organs, such as the brain and the lung, from damage induced by subsequent hypoxia or ischemia. Acute mountain sickness (AMS) is a syndrome of nonspecific neurologic symptoms and in high-altitude pulmonary edema excessive hypoxic pulmonary vasoconstriction (HPV) plays a pivotal role. We hypothesized that RIPC protects the brain from AMS and attenuates the magnitude of HPV after rapid ascent to 3,450 m. Forty nonacclimatized volunteers were randomized into two groups. At low altitude (750 m) the RIPC group (n = 20) underwent 4 × 5 min of lower-limb ischemia (induced by inflation of bilateral thigh cuffs to 200 mmHg) followed by 5 min of reperfusion. The control group (n = 20) underwent a sham protocol (4 × 5 min of bilateral thigh cuff inflation to 20 mmHg). Thereafter, participants ascended to 3,450 m by train over 2 h and stayed there for 48 h. AMS was evaluated by the Lake Louise score (LLS) and the AMS-C score. Systolic pulmonary artery pressure (SPAP) was assessed by transthoracic Doppler echocardiography. RIPC had no effect on the overall incidence (RIPC: 35%, control: 35%, P = 1.0) and severity (RIPC vs. CONTROL: P = 0.496 for LLS; P = 0.320 for AMS-C score) of AMS. RIPC also had no significant effect on SPAP [maximum after 10 h at high altitude; RIPC: 33 (SD 8) mmHg; controls: 37 (SD 7) mmHg; P = 0.19]. This study indicates that RIPC, performed immediately before passive ascent to 3,450 m, does not attenuate AMS and the magnitude of high-altitude pulmonary hypertension.NEW & NOTEWORTHY Remote ischemic preconditioning (RIPC) has been reported to improve neurologic and pulmonary outcome following an acute ischemic or hypoxic insult, yet the effect of RIPC for protecting from high-altitude diseases remains to be determined. The present study shows that RIPC, performed immediately before passive ascent to 3,450 m, does not attenuate acute mountain sickness and the degree of high-altitude pulmonary hypertension. Therefore, RIPC cannot be recommended for prevention of high-altitude diseases.

Concomitant femoro-femoral bypass graft during surgery for acute type A dissection to treat lower limb malperfusion.

We report the case of a 69-year-old male patient who was admitted to our department with an acute type A dissection complicated by ischemia of the left lower limb. During surgery for acute type A dissection, the patient underwent concomitant femoro-femoral crossover bypass graft placement to ensure blood supply of the left lower limb during surgery and minimize ischemia-reperfusion injury. The patient underwent supracoronary replacement of the ascending aorta while in deep circulatory arrest with a deepest core temperature of 25°C. Postoperative computed tomography showed antegrade perfusion and patency of the crossover bypass. Postoperative course was eventless without sequelae, especially of the left lower limb. We conclude that concomitant crossover bypass graft reduces the risk of ischemia-reperfusion injury in lower limb ischemia in patients undergoing surgery for acute type A dissection.

Establishment of Extracorporeal Circulation under Local Anesthesia in a Patient with an Acute Type A Aortic Dissection Complicated by Cardiac Tamponade.

We report the case of an 82-year-old female who presented in a hemodynamically unstable condition to the emergency department of our institution. Transthoracic echo showed a hemodynamically relevant pericardial effusion and the suspicion of an intimal flap in the ascending aorta. The subsequent computed tomography scan revealed a Type A dissection that was limited to the ascending aorta. To prevent hemodynamic deterioration the patient was prepped and draped awake and underwent femoral cannulation for extracorporeal circulation under local anesthesia. After commencing extracorporeal circulation the patient was anesthetized and intubated. During this whole time period no relevant drop in mean arterial pressure was observed. The patient underwent routine replacement of the ascending aorta and was extubated the day after surgery without any neurologic sequelae. Awake cannulation and inception of extracorporeal circulation can prevent the hemodynamic deterioration and cardiac arrest often seen during induction of anesthesia in patients with cardiac tamponade.