Titrate to equilibrate and not exsanguinate! Characterization and validation of a novel partial resuscitative endovascular balloon occlusion of the aorta catheter in normal and hemorrhagic shock conditions.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a significant advancement in the control of noncompressible truncal hemorrhage. However, its ischemic burden and reperfusion injury following balloon deflation limits its utilization. Partial restoration of aortic flow during REBOA has the potential to balance hemorrhage control and ischemia. This study validates the mechanics, physiology, and optimal partial flow rates using a prototype partial REBOA (pREBOA) device. METHODS: Twenty-five swine underwent placement of aortic flow probes and zone 1 pREBOA. Experiment 1 (N = 5) animals were not injured and assessed the tested the catheters ability to titrate and control flow. Experiment 2 (N = 10) added 20% hemorrhage and either solid organ, or abdominal vascular injury to compare flow rate and rebleeding from injuries. Experiment 3 (N = 10) swine were similarly prepared, hemorrhaged, and underwent pREBOA at set partial flow rates for 2 hours followed by complete deflation for 30 minutes. RESULTS: Balloon volume at minimum flow (mean, 0.09 L/min) was 3.5 mL to 6.0 mL. Half maximal flow was achieved with 56.5% of maximum balloon inflation. Partial REBOA allowed very fine titration of flow rates. Rebleeding occurred at 0.45 L/min to 0.83 L/min. Distal flow of 0.7 L/min had 50% survival, 0.5 had 100% survival, and 0.3 L had 50% survival with mean end lactates of 9.6, 12.6, and 13.3, respectively. There was a trend toward hyperkalemia and hypocalcemia in nonsurvivors. CONCLUSION: The pREBOA device demonstrated a high level of titratability for restoration of aortic flow. An optimal partial flow of 0.5 L/min was effective at hemorrhage control while limiting the burden of ischemic injury, and extending the tolerable duration of zone 1 occlusion. Aggressive calcium supplementation prior to and during partial occlusion and reperfusion may be warranted to prevent hyperkalemic arrest.

Intra-Arterial Perimortem Resuscitation Using a Micellar Colloid.

OBJECTIVE: The following were studied in a perimortem mouse model of rapid blood loss: (a) efficacy of a prototypical micellar colloid, Intralipid 20%, (IL20), compared to albumin (b) comparison of intra-arterial and intravenous resuscitation, (c) efficacy of IL20 at a volume 2 × the volume of blood removed, and (d) efficacy of oxygenated IL20 after clinical death (CD). METHODS: CD, the absence of breathing and zero blood pressure (BP), was produced by removing 55% of the blood volume within 3 minutes. After CD, the chest was opened to observe ventricular contraction. IL20, Ringer's lactate (RL), or albumin was infused perimortem. RESULTS: Without resuscitation CD occurred in 2.85 ± 0.40 minutes. Ventricular contraction persisted 20.50 ± 1.11 minutes after CD. RL infused immediately after CD restored breathing if given intra-arterially but not intravenously. IL20 was superior to the prototypical colloid, albumin in maintaining the BP. Increasing the volume of IL20 further increased BP. Delayed RL infusion after CD failed to restore breathing. Delayed resuscitation after CD with oxygenated IL20 restored breathing and BP. CONCLUSIONS: Micellar colloid is superior to the prototypical colloid albumin and can possibly be of use when signs of life are no longer present. In extremis, intra-arterial infusion is superior to intravenous infusion.

Exsanguination by intent: controlled phlebotomy during resection of a giant vascular malformation in a 22-month-old child.

Resection of large vascular malformations may require transection across the lesion, resulting in uncontrollable bleeding with the risk of exsanguination or massive transfusion-related complications such as hyperkalemic cardiac arrest. We present the anesthetic management of a 22-month-old child with a giant vascular malformation who required surgical intervention because of increasing pain and bleeding from the lesion. As a standard resection carried a high risk of mortality for the patient, a novel surgical approach was performed, consisting of gradual compression of the lesion, reducing its base to allow transection across the smallest possible area. This compression resulted in acute massive autotransfusion managed by therapeutic phlebotomy of more than twice the circulating blood volume of the patient, guided by CVP and blood pressure. Although subsequent resection was still associated with large blood loss, the hemodynamic course of the patient was stable, and both bleeding and massive transfusion occurred in a controlled fashion allowing safe and successful resection of the malformation.

The Isolated Arm Test for the Assessment of Neuromuscular Blockade / 대한마취과학회지

Subjects should not have any factors affecting neuromuscular transmission. Anestheisa was induced by a sleep dose of 2.5% thiopental sodium, and oxygen, nitrous oxide and lower concentration of enflurane were used for maintenance. When the patients were stabilized, the arm with electrode attached and an indwelling needle inserted into a vein on the back of the wrist, was elevated for 30 seconds to partially drain the blood from it and then pneumatic tourniquet inflated 30 to 40 mmHg above the systolic blood pressure around the upper arm, so that a small dose of relaxants (1/60 or 1/30 of the clinical dose; succinylcholine 1mg/kg, vecuronium 0.08 mg/kg, atracurium 0.2 mg/kg, pancuronium 0.08 mg/kg and alpha-tubocurarine 0.2 mg/kg) could be injected into the arm isolated from the systemic circulation. Thereafter, ischemia was maintained for 4 minutes to allow retrograde spread of some of the drugs into the capillary bed where neuromuscular block was established. At the end of 4 minutes after tourniquet applied, the tourniquet was released. Neuromuscular conduction was recorded using ABM monitor of the Datex Co. for neuromuscular transmssion by 40 mA 2Hz stimulaton to ulnar nerve 20 seconds interval. We confirmed the marked rundown of amplitude of muscle action potensial (MAP) in group injected very small doses throughout the isolated limb but no affect the evoked MAP in group injected into systemic circulation. Conclusively, even there are various factors affecting extent of block by the tournique; ischemic acidosis, concentration volume of drugs, amovnt of exsanguination and the state of vasculare bed, these were not thought to be a source of error for study. Therefore small doses of relaxants required wih this technique exclude the possibility of unwanted systemic side effects and can be reliable and effective for clinical study for neuromuscular transmission.