Table 5.

Normal limits of blood gas, saturations, and hematocrit during adult CPB.

Parameter	N	Mean	SD	Q1	Median	Q3	IQR	Mode	Low 95 CI	High 95 CI
Continuous monitoring mixed venous saturation (%)
Low limit	133	63	6	60	65	65	5	65	60	65
High limit	132	86	6	80	85	90	10	85	85	85
Cerebral NIRS regional saturations (%)
Low limit	69	50	11	43	50	60	17	50	45	50
High limit	69	82	9	75	80	90	15	80	80	85
PaO2 values: what are the normal limits (mmHg)?
Low limit	129	157	52	122	150	185	63	150	150	150
High limit	128	320	94	250	300	350	100	300	300	320
PaCO2 values: what is the normal limits (mmHg)?
Low limit	129	36	8	35	35	36	1	35	35	35
High limit	129	50	23	45	46	50	5	45	45	48
Sweep gas: gas-to-blood flow ratio normothermic CPB (%)
Low limit	113	53	21	40	50	60	20	50	50	50
High limit	113	88	27	75	80	100	25	100	75	100
Normal HCT: what is the patient’s normal HCT (%)?
Before bypass	131	35	3	33	35	36	3	35	34	35
During bypass	131	26	3	24	25	28	4	25	25	26
After bypass	131	29	3	26	29	30	4	30	28	30
Bicarbonate administration: what is the base excess (mEq/L) to give bicarbonate?
Base excess (negative mEq/L)	129	−3.5	1.5	−4.0	−3.0	−2.0	2.0	−4.0	−3.7	−3.2
Normal pH: what is the patient’s normal pH?
Normal pH during CPB	134	7.39	.04	7.38	7.40	7.40	.02	7.40	7.38	7.40

Descriptive statistics for survey blood gas-, hematocrit-, and pH-related parameters. n is the number of respondents, mean is the average of responses, SD is one SD, Q₁ is the 25th percentile, median is the 50th percentile, Q₃ is the 75th quartile, and mode is the most frequent response. The parameter responses did not fit a normal distribution. Low and high 95 CIs are the limits for the 95% CI for the median. Log pH values were converted to linear hydrogen ion activity values to perform the statistical analysis. About 98% of respondents report continuous monitoring of mixed venous saturation during CPB. About 46% of respondents report continuously monitoring cerebral regional saturations.