Fever in goldfish is induced by pyrogens but not by handling

OBJECTIVE: To determine whether end-tidal partial pressure of carbon dioxide (PETCO2) was a reliable estimate of PaCO2 in dogs undergoing thoracotomy. DESIGN: Case series. ANIMALS: 18 dogs that underwent thoracotomy. PROCEDURE: PaCO2 and PETCO2 were measured shortly after induction of anesthesia, while dogs were breathing spontaneously; 5 minutes prior to initial skin incision, while dogs were receiving intermittent positive-pressure ventilation (IPPV); 5, 30, and 60 minutes after the thoracic cavity was opened, while dogs were receiving IPPV; and after the thoracic cavity was closed and evacuated, when dogs were again breathing spontaneously. For each period, arterial-end-tidal difference in partial pressure of carbon dioxide (PaCO2-PETCO2) was compared with PaCO2-PETCO2 for the preceding period. RESULTS: Significant changes in PaCO2-PETCO2 from one period to the next were not detected except when values obtained 5 minutes after the thoracic cavity was opened were compared with values obtained 5 minutes before incision. The PaCO2-PETCO2 was not constant for individual dogs. CLINICAL IMPLICATIONS: PETCO2 was not a reliable indicator of adequacy of ventilation during thoracotomy in these dogs, because it differed greatly from PaCO2, and PaCO2-PETCO2 was not consistent.