End-tidal CO2 Measurement Via Nasal Cannula in Spinal Anesthesia / 대한마취과학회지

BACKGROUND: Major respiratory problems during spinal anesthesia occur due to several causes, particulary, high spinal block, use of sedatives or opioids, and underlying cardiopulmonary diseases. Pulse oximetry has prevented most of these problems, but has not provided rapid and accurate information of the patient's ventilation. We measured end-tidal CO2 tension via the side-stream capnometer with a small rubber cannula and investigated its effectiveness in ventilatory monitoring under spinal anesthesia. METHODS: Nineteen patients were involved in this study. We performed spinal anesthesia with 0.5% heavy marcaine 12 mg (L3-4 interspace). After fixation of spinal sensory blockade level, 0.035 mg/kg of midazolam was administered intravenously to sedate the patient. A polyvinylchloride catheter with a rubber extending nasal cannula was used for sampling of respiratory gas. PETCO2 was measured at 15 minutes after spinal anesthetic injection (before sedation), and at 5 minutes after midazolam injection (after sadation). Arterial CO2 tension was also measured during PETCO2 measurement. RESULTS: There was no correlation of spinal maximal sensory blockade level with repiratory rate, PaCO2 and PETCO2. Linear regression analysis of arterial vs. end-tidal CO2 yielded a slope of 0.92, r=0.81 and p<0.001 (before sedation), and a slope of 0.98, r=0.79 and p<0.01 (after sedation). Arterial to end-tidal differences were 4.2+/-2.8 mmHg (before sedation) and 4.3+/-3.0 (after sedation), but there was no significant difference in comparing them with each other. Conclusions : We conclude that this form of PETCO2 measurement is useful in continuous, noninvasive monitoring of ventilation in patients under spinal anesthesia.

Influence of sodium nitroprusside-induced hypotension on the difference between arterial and end-tidal CO_2 tension in dogs / 中华麻醉学杂志

0.05) in both groups. In group B,cardiac output decreased by 13% at 15th min following deliberated hypotension (P0.05). It is suggested that PaCO_2 can be evaluated continuously and noninvasively by monitoring end-tidal CO_2 tension during SNP-induced hypotension.

Influence of controlled hypotension Induced by PGE_1 on the difference of arterial and endtidal CO_2 tension in dogs / 中华麻醉学杂志

0. 05),cardiac index decreased from 12. 5% to 13. 3 % during hypotension (P 0. 05 ). It was concluded that PaCO2 can still be followed continuously and noninvasively by monitoring end-tidal CO2 tension during hypotension induced by PGE,

Relationship between Arterial and End-tidal CO2 Tensions in Anesthetized Infants and Children / 대한마취과학회지

End-tidal (PETCO2) and arterial CO2, tensions (PaCO2) were measured in 66 anesthetized infants and children. 35 patients were under 7 year-old (group 1) and 31 patients were over 7 year-old (group 2). In both groups, differences between PETCO2, and PaCO2, were evaluated, and correlations between PETCO2, and PaCO2, were carried out. The children in group 1 had a PaCO2, (mean+/-S.D.) of 29.2+/-4.1mmHg and a PCO2, (mean+/-S,D.) of 29.2+4.1mmHg. The range of the PaCO2, and PETCO2 difference (P alpha-ETCO2) was from -1.0 to 1.2 mmHg. The children in group 2 had a PaCO2 (mean+/-S.D.) of 29.3+/-3.0 mmHg and a PETCO2 (mean+/-S.D.) of 29.3+/-4.0mmHg. The range of the P alpha-ETCO2 was from 1.9 to 2.5mmHg. The significant direct correlations between PaCO2 and PETCO2 in both groups (r=0.96,0.84, respec-tively) were defined. The difference between groups wasnt statistically significant. It is concluded that in normal infants and children during anesthesia, noninvasive measurement of PET CO2 can be used as a reliable estimate of PaCO2 and that PETCO2did not differ significantly from PaCO2.