Takayuki Nishigaki

Early experience with low-prime (99 ml) extracorporeal membrane oxygenation support in children

Quick setup is mandatory for cardiopulmonary resuscitation using an extracorporeal membrane oxygenation (ECMO) assist device. Our conventional ECMO circuit for pediatric patients consists of a centrifugal pump (CX-HP) and membrane oxygenator (CX10H). Because of the large priming volume (260 ml), the circuit had to be primed with donor blood and required 30 minutes for setup. We started to use a low-prime ECMO with small centrifugal pump (HPM-15) and membrane oxygenator (MENOX Alpha Cube) for induction of ECMO beginning in 2000. The priming volume of this low-prime circuit is only 99 ml. The circuit can be primed without donor blood, even in the small patient, and requires only 10 minutes to set up. We review our experiences with cardiopulmonary resuscitation for sudden cardiopulmonary collapse in pediatric patients, including postcardiotomy patients. From 1997 to 2000, 23 patients underwent ECMO support with a conventional circuit (group A). From 2000 to 2004, we used low-prime circuit for induction of ECMO in 12 patients (group B). After the induction of ECMO with low-prime circuit, ECMO was converted to conventional heparin-bonded circuit for the longer support. The results suggested that the quick induction of ECMO with low-prime circuit has significant advantages in cardiopulmonary support in pediatric patients.

High Stroke Volume Variation Is an Independent Predictor for Decreased Blood Pressure During Hemodialysis

It currently remains unclear whether stroke volume variation (SVV) before hemodialysis (HD) is an independent predictor of decreased blood pressure (BP) during HD. Fifty‐two patients were divided into two groups (Decreased BP during HD group: N = 10, Non‐decreased BP group: N = 42). Fractional shortening was lower, and mean arterial pressure (MAP) and SVV were higher in the Decreased BP during HD group. A multiple logistic regression analysis identified low fractional shortening, high MAP, and high SVV as independent predictors of decreased BP during HD. The areas under the ROC curves were as follows: 0.849 for MAP, 0.712 for SVV, and 0.893 for MAP and SVV. Optimal threshold values were 93.0 mm Hg for MAP and 17.3 % for SVV. A multivariate regression analysis identified anemia and a longer dialysis vintage as independently related factors for higher SVV. Our results suggest that high SVV is an independent predictor for decreased BP during HD.

Frequency analysis of shunt sounds in the arteriovenous fistula on hemodialysis patients

The aim of this research is to evaluate vascular access (VA) using shunt sounds. We measured the blood flow volume in the brachial artery (FV) and the resistance index (RI) by using ultrasonic diagnostic equipment, and the frequency and spectrum characteristic to the shunt sounds by using an electronic stethoscope. The subjects were fifty hemodialysis patients who had been treated with arteriovenous fistura (AVF). An electronic stethoscope was used for all the subjects to record the shunt sounds of arteriovenous anastomosis with an 8 kHz sampling frequency for 8 seconds. The digitized sound was analyzed by the Fourier transform, and every 10 Hz spectra were examined for acoustic amplitude and spectral energy distribution. Based on the ultrasonographic data, subjects FV >= 500 mL/min) and II (FV < 500 mL/min), and Groups A (RI < 0.6) and B (RI >= 0.6). Spectra distribution on frequency bands were compared between two different groups. The spectra in 41–270 Hz were significantly higher in Group I than in Group II. In Group I, the spectra in 111–160Hz were significantly higher than those in other frequency bands. In Group II, the spectra in 121–140 Hz were significantly higher than in the other frequency bands. Comparing Groups A and B, Group A showed a significantly higher spectrum in the 51–270 Hz, and in particular, the spectra of 121–160 Hz showed significantly higher compared with those of the other frequency bands. In group B, spectra of 131–140 Hz showed significantly higher compared with those of the other frequency bands. From these results, shunt sounds acquired in patients with good AVF function (FV >= 500 mL/min or RI < 0.6) were larger in the spectra of a 51–270 Hz frequency bands and were broad in the frequency domain compared with those in patients with poor AVF function (FV < 500 mL/min or RI >= 0.6). It was found that analyzing the amplitude and frequency features of spectra in shunt sounds would be used for identifying FV and RI.

Present state of CPB training for students.

要旨臨床工学技士養成課程における臨床実習のうち手術室における業務は主要4部門のひとつである。日本臨床工学技士会が提唱する臨床実習指導ガイドラインでは、装置や構成に関する理解および、チーム医療に対する役割の理解などが目標に掲げられている。しかしながら各実習施設における具体的な実習の内容に関する報告は少なく、その詳細については不明な点が多い。今回、人工心肺実習に対する認識および満足度に関してアンケートを行った。対象は、日本国内の実習施設3施設の手術室で臨床実習(人工心肺)を受けた臨床工学技士養成課程の学生47名と、厚生労働省循環器従事者研修生4名の計51名で、12項目から構成される人工心肺実習に関連する認識・満足度アンケートを行った。将来的に人工心肺操作を希望すると答えた学生は全体の84%であった。一方、卒業後に人工心肺の操作が技術的にできる自信があると答えた学生は2%であった。今回の調査により、臨床実習上の潜在的な問題点が抽出された。今後、実習施設問および養成校において継続した協議・検討を重ねていく必要がある。