In Reply

It is very important to optimize cardiac output and oxygen delivery by optimizing fluid therapy, and pulse pressure variation can help to identify fluid responsiveness. Dr. Sondergaard is right in underlining all the limitations of pulse pressure variation, but anesthesia provides an ideal setting for the use of pulse pressure variation as there is no spontaneous breathing effort during controlled mechanical ventilation and usually no bronchospasm or right heart failure.

Dr. Sondergaard reinforces our provocative statement that we may not have to measure cardiac output during surgery¹  when he writes that “YES, we have to measure cardiac output in high-risk surgery to optimize oxygen delivery” without detailing how the measurement can help practically; this sounds to us rather like dogma.