A Thesis from Japan [ 8 ] Pediatric Q Rates ?

Presentation authored by:  Hiroyuki Kuromitsu (Hiro)

Editor’s Note:

Hiro Kuromitsu is very active as a Japanese perfusionist, and has been an on-line FaceBook friend for quite some time.  He will be presenting a paper on Pediatric Flow Rates / CPB at the 21st Annual Meeting of the Asian Society for Cardiovascular and Thoracic Surgery in Kobe, Japan, 2013.

He asked that I assist in some English grammar issues, and offered an abstract of his presentation below.

Fundamental Research for Establishing and Reconsideration of Optimal Flow Rates in Pediatric Cardiopulmonary Bypass:

From the viewpoint of preoperative catheter data

Authored By:  Hiroyuki Kuromitsu (Hiro)

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OBJECTIVE

In the late 1950s, there was much research and focus for establishing a basic standard in terms of optimal flow rates (cardiac index) while supporting pediatric patients on cardiopulmonary bypass (CPB).

When reviewing this literature, determining optimal flow rates is most commonly derived from the preoperative cardiac index (C.I.) of the individual patients. As a general rule of thumb, it has been established that an appropriate C.I. is approximately 2.0 to 2.4 L/min/ m2, and that standard has held and is currently in use  today.

With today’s technology and advances in pediatric heart surgery, consideration must allow for the fact that pediatric cardiac surgery cases are becoming more complex and that the patient population is trending towards lower birth weight babies.

With this consideration in mind, we thought that it might be necessary to reconsider the earlier established standard and determine whether or not it is suitable to current situations in pediatric CPB.

The foundation of our approach is a retrospective study of prior patient cardiac catheterization data to obtain optimal flow rates on pediatric patients undergoing CPB. As a first step, we calculated the predicted optimal  C.I. of patients who underwent pediatric cardiac surgery from existing cardiac catheterization  data, allowing us to be able to establish the necessary optimal pediatric flow rates for their respective surgeries.

METHODS

The patient population in our retrospective study included 1,278 children who underwent pediatric cardiovascular surgery from January 1988 to December 2012.  The preoperative catheter data; “SvO2, SaO2, and hemoglobin values” were extracted from our pediatric cardiac surgery database. The oxygen consumption rate was derived from Clark’s oxygen consumption curve according to each patient’s  body weight, and their C.I. was calculated using the Fick equation. A statistical analysis was performed to identify any correlation between body weight and cardiac index.

RESULTS

Statistical analysis, failed to demonstrate any correlation between patient weight and C.I.. It was noted however, that the calculated C.I. range was approximately 2.42 – 4.31 L/min/m2 in each classification. The peak cardiac index “4.31 L/min/m2” was associated with patients in the 12-13 kg range. This suggest that patients in the weight range of 12-13 kg might need to be perfused at higher cardiac perfusion rates.

CONCLUSIONS

A usual perfusion index was much less than Cardiac Index. A peak of required flow rate differed with peak of Clark’s oxygen consumption curve.

Any Comments, Suggestions, or Opinions  ?