Reliability of temperatures measured at standard monitoring sites as an index of brain temperature during deep hypothermic cardiopulmonary bypass conducted for thoracic aortic reconstruction

Abstract

Pulmonary artery temperature measurement is recommended to estimate brain temperature during deep hypothermic cardiopulmonary bypass, even if it is conducted with the sternum opened; however, caution needs to be exercised in interpreting its measurements during periods of the cardioplegic solution infusion.

Induction of Cooling With a Passive Head and Neck Cooling Device

“…This may be attributable to selective brain cooling as concluded by Wang et al 10 or may be a delayed response of bladder temperature during rapid temperature changes when compared with other body core temperatures. 23 Regarding treatment effects on blood pressure Koehn et al 13 and Kallmünzer et al 12 reported conflicting data in healthy volunteers. Interestingly, Koehn et al 13 observed an immediate increase of blood pressure on cooling onset followed by a steady increase over a 2-hour time period, whereas the blood pressure increase in our study was also immediate, but transient (Figure 2).…”

Perioperative temperature measurement and management: moving beyond the Surgical Care Improvement Project

“…Nasopharyngeal and urinary bladder temperatures correlate well with pulmonary artery temperature except during rapid changes [17]. The temperature measured in the bladder does not reflect core temperature accurately in all patients, in fact, in some patients the measured temperature may vary more than measured skin temperature [17]. Less accurate sites include tympanic, rectal, and deep tissue thermometry.…”

“…Since the jugular bulb receives the majority of cerebral blood flow, it is thought to correlate to temperature in the cerebral cortex [17]. However, there is no evidence that measuring jugular bulb temperature or intraparenchymal temperature, compared to other measurements of core body temperature, improves outcomes and they are highly invasive monitors.…”

“…The temperature measured from the pulmonary artery is a close approximation of the jugular bulb temperature and even correlates well during rapid changes in surgical procedures involving deep hypothermic circulatory arrest [17]. Detecting temperature from the pulmonary artery requires an invasive catheter.…”

“…Regardless of whether the tympanic site is measured by infrared technology or with a thermocouple, it is difficult to place correctly [15]. Rectal temperature has been shown to adjust more slowly than other sites for measuring core temperature contributing to its lower accuracy [15,17]. The least accurate location to measure temperature is the skin as it is subject to peripheral vasoconstriction induced by thermoregulatory mechanisms in the presence of hypothermia [16].…”