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.
We proposed a new heating system (NHS) for an ECMO for children. This time we studied the heat retention effects and condensation prevention effects of the NHS with basic experiments. The experimental equipment consisted of three elements: the NHS, an experimental ECMO system, and an experimental heat exchanger. The NHS consisted of a convective air warming system and a vinyl sheet to cover the ECMO system. The first experimental method recorded the transitions in the circulating water temperature in the ECMO system for each of 8 types of ECMO management methods. Another test method studied whether condensation occurred in the NHS equipment and in the control equipment over 12 hours of ECMO operation. The results showed that the NHS has the heat exchange performance and the condensation prevention effect needed for ECMO management. This strongly suggested that the NHS most likely be put into practical use.
In maintenance hemodialysis treatment, dialysis hypotension, whereby the blood pressure suddenly drops during treatment, is a common complication at the actual treatment sites. The aim of this paper is a study on how fostering crus venous return during dialysis has an impact on blood pressure and mood/feeling changes. The subjects were 19 patients (10 males and 9 females) undergoing maintenance hemodialysis. We used crus pneumatic compression to foster venous return. Four experimental conditions were set and a comparison was done between the control condition and each of the conditions using crus pneumatic compression. The experimental conditions were as follows: condition 1 was the control condition, condition 2 used crus pneumatic compression set for 40mmHg and a 30second interval, and condition 3 used crus pneumatic compression that automatically adjusts to the venous return speed of the patient. The measurement items were blood pressure rate of change, circulator blood volume rate of change (ΔBV), sensation change (crus thermal sensing and feeling of lightness), and a mood evaluation scale (POMS). The result of our study is that only the control condition showed a significant decrease in blood pressure rate of change, during the latter half of dialysis, and the conditions fostering venous return did not show such a decrease. ΔBV also showed a slope matching that of blood pressure change but condition 3 showed a slope similar to condition 1. There was a significant improvement in the visual analogue scale values (VAS values) for thermal sensing and feeling of lightness in conditions 2 and 3 when comparing the values for before dialysis, after dialysis, and after returning home. In POMS, condition 2 showed significantly lower values compared to condition 1 in the scales of [depression-dejection (D)] and [Anger-Hostility (A-H)]. By implementing this method, it seems that a reduction in dialysis hypotension pathogenesis and comfortable mood/sensation changes can be attained.
Patients requiring hemodialysis have a variety of dialysis-associated complications. In particular, hypotension is a potential complication of chronic hemodialysis patients, which unexpectedly occurs during treatment and interrupts the continuation of dialysis, creating feeling of distress for the patients. Recently, the Crit-Line monitor has been clinically used and the signs of dialysis hypotension can be recognized by monitoring the blood volume changes (ΔBV) before the actual onset of the disease. However, the Crit-Line monitor is not omnipotent and can only help to prevent the development of dialysis hypotension secondarily and in a predictive way. In light of stabilizing blood pressure during dialysis and preventing dialysis-associated hypotension, we have focused on the venous return as a factor leading to stabilization of the blood volume changes ΔBV, and investigated the possibility that accelerated venous return results in maintaining blood pressure during hemodialysis. The subjects of this study are 8 hemodialysis patients on maintenance.We used a sequential pneumatic compression massage tool (foot pump) to accelerate the venous return during hemodialysis. First, the venous return was accelerated by a continuous massage with foot pumps during hemodialysis. Conditions of the massage were classified into 3 categories: Condition ① was no massage (control), Condition ② was a slight massage, and Condition ③ was a hard massage. Values of ΔBV were observed under these conditions for two weeks. As a result, more significant stabilization of ΔBV in the latter half of hemodialysis session was found in the groups with massage. Sensory changes were also studied and compared: Pre-dialysis, post-dialysis, and after returning home. In Condition ② a significantly better result of sensory changes was obtained after dialysis than before dialysis. Furthermore, it was confirmed that massage prevents peripheral circulation by measuring the transcutaneous partial pressure of oxygen (tcPO2), which was monitored continuously during hemodialysis. Consequently, any changes showing significant differences were not found during dialysis. In this study, a possible prevention of dialysis hypotension by accelerating the venous return is discussed.
