Keisuke Ichinose

Airway obstruction involving a laryngeal mask airway during arthroscopic shoulder surgery

Several earlier reports have described life-threatening airway obstruction during arthroscopic shoulder surgery performed under regional anesthesia, caused by the leakage of irrigation fluid out of the shoulder joint space into the surrounding soft tissues and then the neck and the pharynx. Here, we present a case of airway obstruction that occurred in a patient under general anesthesia. A 77-year-old woman with a rotator cuff rupture who was to undergo right-shoulder arthroscopic surgery was anesthetized with fentanyl and propofol. Her airway was secured with a flexible laryngeal mask airway (LMA). During surgery, the compliance of her breathing bag became gradually poorer, and finally we were not able to ventilate her at an airway pressure of 60 cmH2O. We found that her chest wall, neck, and face were swollen and tense. Laryngoscopy revealed massive swelling of the pharyngeal soft tissues. The vocal cords were not visible. Her trachea was intubated blindly, and adequate ventilation was re-established. She was placed in the Fowler position and furosemide was given intravenously. Her neck and chest swelling were reduced over the next 2 h and she was extubated without any problem. We recommend that physicians should periodically examine the neck of any patient undergoing arthroscopic shoulder surgery, especially when general anesthesia is used, because anesthetized patients cannot complain of breathing difficulty and the airway swelling may progress until it becomes life-threatening.

Preliminary experiment with a newly developed double balloon, double lumen catheter for extracorporeal life support vascular access.

Recently, venovenous extracorporeal life support (VVECLS) using a double lumen catheter has been clinically used to avoid neurologic complications in the treatment of respiratory failure for neonates. However, recirculation, which is a limiting factor for oxygen delivery, still exists, and thus it does not contribute to oxygenation of the patient. We developed a newly designed double lumen catheter with a double balloon (DBDL) catheter for ECLS vascular access and performed two animal preliminary experiments in normal and hypoxic dog models (normal ventilation and one lung ventilation experiments) to investigate whether the DBDL catheter could prevent recirculation and maintain oxygen delivery to systemic circulation. The DBDL catheter (JCT Co., Hiroshima, Japan) of 15 Fr was fabricated from silicone. It consists of two lumens for drainage and return of blood with two balloons (distal and proximal balloons) that prevent oxygenated blood mixing with unoxygenated blood. VVECLS using a DBDL catheter was performed in 13 mongrel dogs (8 dogs for normal ventilation experiment weighing 12.9 ± 1.6 kg [mean ± SD], 5 dogs for one lung ventilation experiment weighing 16.6 ± 2.5 kg [mean ± SD]) under anesthesia in the two experiments. The bypass flow ranged from 10–40 ml/kg per minute in the normal ventilation experiment. VVECLS in the one lung ventilation experiment was performed with maximal bypass flow for 6 hours (ranged from 25.2 ± 8.0–28.3 ± 8.7 ml/kg per minute at balloon inflation and deflation). Recirculation and oxygen transfer of artificial lung with or without balloon inflation during VVECLS were studied. Recirculation decreased with balloon inflation at varied bypass flows during VVECLS in the normal ventilation experiment (varied from 1.5 ± 14.6–12.8 ± 16.7%) and for 6 hours after VVECLS initiation in the one lung ventilation experiment (varied from 12.2 ± 12.2–19.2 ± 6.5 %). In particular, the values at 3 and 6 hours were significantly lower than that of balloon deflation in the one lung ventilation experiment. The difference in O2 content between inlet and outlet in the artificial lung with balloon inflation was significantly higher than that of balloon deflation (varied from 3.7 ± 1.8–4.8 ± 1.9 ml/dl, p < 0.05) at the bypass flow of 10–30 ml/kg per minute in the normal ventilation experiment and at 5 hours after VVECLS initiation in the one lung ventilation experiment (varied from 10.6 ± 1.6–11.7 ± 1.8 ml/dl). The blood gas analysis of systemic circulation with balloon inflation revealed that the values of PaO2 (varied from 83.8 ± 11.4–96.9 ± 23.4 mm Hg) and PaCO2 (37.7 ± 9.2–40.4 ± 11.8 mm Hg) were higher and lower, respectively, compared with balloon deflation. In particular, PaO2 level was significantly higher than that of the preECLS value at the bypass flow of 20–40 ml/kg per minute (varied from 83.8 ± 11.4–96.9 ± 23.4 mm Hg, p < 0.05). In the one lung ventilation experiment, systemic PaO2 and PaCO2 levels at balloon inflation were higher and lower, respectively, compared with balloon deflation during VVECLS for 6 hours. At balloon inflation, the value of PaO2 at 6 hours after VVECLS initiation was significantly higher than that at balloon deflation. A newly designed DBDL catheter for ECLS vascular access successfully reduced recirculation and maintained oxygen delivery to systemic circulation during VVECLS. These results suggest that a high bypass flow may not be necessarily required in terms of oxygen delivery to systemic circulation when the DBDL catheter was used as an ECLS vascular access.

Does veno-arterial bypass without an artificial lung improve the outcome in dogs undergoing cardiac arrest?

We hypothesized that maintaining circulation and blood pressure by veno-arterial bypass (V-A bypass) without oxygenation would improve cardiopulmonary resuscitation (CPR) and survival rates. A total of 32 dogs, divided into four groups, were subjected to normothermic ventricular fibrillation (VF) for 15 min. The method of CPR was the same in the four groups, except for the method and timing of V-A bypass. We attempted to resuscitate the dogs without V-A bypass (control), with V-A bypass not including an artificial lung during VF, with V-A bypass not including an artificial lung during CPR, and with V-A bypass including an artificial lung during CPR. CPR was continued until restoration of spontaneous circulation (ROSC) or for 30 min. Although blood pressure was well maintained, severe hypoxemia was observed during V-A bypass without an artificial lung. The resultant hypoxemia was very detrimental. ROSC was achieved more easily in all dogs in the bypass group with an artificial lung. No significant difference in survival rates was demonstrated among the four groups (P = 0.11). We concluded that V-A bypass without oxygenation does not improve the chances for CPR and outcome after cardiac arrest in dogs. Our results suggest that oxygenation is indispensable in CPR.

Preoperative acute hypervolemic hemodilution with hydroxyethylstarch in a Jehovah's Witness: effects on hemodynamics and coagulation systems

The increased attention to the risks associated with homologous blood transfusion has provided the impetus for the development of techniques to minimize transfusion. Transfusion with donor blood may be diminished by the use of predeposited autologous blood, intraoperative autotransfusion with a cell-saving device, and hemodilution techniques. Preoperative hemodilution can be achieved either by withdrawal of blood and simultaneous infusion of fluid, i.e., normovolemic hemodilution (ANH), or by rapid infusion of fluid without blood withdrawal, i.e., acute hypervolemic hemodilution (AHH). A H H is induced by hemodilution with hydroxyethylstarch preoperatively without removing autologous blood, and in order to prevent the hemodynamic effect of a large intravascular volume, we must use vasodilators [1-3]. Hypervolemic hemodilution is not time-consuming and requires no special procedure, such as collection and storage of the patients blood [2]. Patients who refuse ANH, such as Jehovahs Witnesses, are particularly good candidates for AHH. However, in patients who suffer from cardiovascular disease, coagulation disorder, renal dysfunction, particular attention should be paid to AHH. We treated a patient who was a Jehovahs Witness and underwent major surgery under general anesthesia. The patient refused blood transfusion on religious