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Background: Acute hypoxemia is the main characteristic of acute respiratory distress syndrome (ARDS), which is one of the most critical complications of coronary artery bypass grafting (CABG). Given the dearth of data on acute hypoxemia, we sought to determine its prevalence and risk factors among post-CABG patients. Methods: This cross-sectional study was conducted on on-pump CABG patients in Tehran Heart Center in 2 consecutive months in 2012. The effects of arterial blood gas variables, age, gender, the duration of the pump and cross-clamping, the ejection fraction, the creatinine level, and the body mass index on the prevalence of hypoxemia at the cutoff points of ARDS and acute lung injury were assessed. Results: Out of a total of 232 patients who remained in the study, 174 (75.0%) cases were male. The mean age was 60.60±9.42 years, and the mean body mass index was 27.15±3.93 kg/m2. None of the patients expired during the current admission. The ratio of partial pressure arterial oxygen to the fraction of inspired oxygen (PaO2/FiO2) 1 hour after admission to the intensive care unit (ICU), before extubation, and at 4 hours after extubation was less than 300 mmHg in 66.6%, 72.2%, and 86.6% of the patients and less than 200 mmHg in 20.8% 17.7%, and 30.2% of the patients, respectively. Among the different variables, only a heavier weight was associated with a PaO2/FiO2 ratio of less than 300 mmHg at 1 hour after ICU admission and at 4 hours after extubation (P=0.001). A rise in the cross-clamp time showed a significant association with the risk of a PaO2/FiO2 ratio of less than 200 mmHg at 4 hours after extubation (P=0.014). Conclusion: This study shows that hypoxemia following CABG is very common in the first 48 postoperative hours, although it is a benign and transient event. The high prevalence may affect the accuracy of the ARDS criteria and their positive or negative predictive value.
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BACKGROUND: Respiratory failure and hypoxemia are the known complications of anesthesia and surgery. As a major surgery mainly at advanced ages, the coronary artery bypass graft (CABG) surgery could lead to hypoxemia in the early post-operative phase. Currently, the fraction of partial pressure of arterial oxygen to the fraction of inspired oxygen (PiO2/FiO2) is used to determine the severity of the respiratory assault. OBJECTIVES: This study aimed to find the effect of hypoxemia measured by PaO2/FiO2 at the first hour following CABG in the determination of short-term prognosis of CABG. METHODS: Being approved by a local ethics committee, this observational cross-sectional study was conducted in 212 patients undergoing CABG on the cardiopulmonary pump, with no concurrent surgery or other cardiac pathologies. Factors like age, sex, weight, height, the duration of pump and cross-clamp, as well as other medical conditions including chronic obstructive pulmonary disease (COPD), diabetes mellitus (DM), opioid use, ejection fraction (EF), and creatinine clearance (CrCl) before the surgery were brought into consideration as possible confounders. The ratio of PiO2/FiO2 in the first hour after the surgery was measured, and its effect on intubation time and intensive care unit (ICU) length of stay was evaluated as the primary outcomes. The t-test and chi-squared were used to compare quantitative and qualitative variables, respectively. The repeated measures ANOVA test was used to compare the means. RESULTS: There was no significant relationship between hypoxemia measured as the ratio of PaO2/FiO2 and the duration of ICU length of stay (P value = 0.220) and the total intubation time (P value = 0.661). Among the qualitative variables, just opium addiction in patients with PaO2/FiO2 > 300 was associated with significantly longer intubation time (P value = 0.016). Furthermore, in the quantitative variables, longer intubation time was associated with higher cross-clamp time (P value = 0.035) in hypoxemia in the range of ARDS patients. CONCLUSIONS: Hypoxemia after the CABG surgery is common and does not affect the short-term prognosis of CABG patients.
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BACKGROUND: Applying the cardiopulmonary pump produces inflammatory responses and induces leukocytosis. White Blood Cell (WBC) count has a diagnostic value for detecting different infections. In this study, we want to redefine the normal value reference intervals of WBC count in Coronary Artery Bypass Graft (CABG) patients, to prevent misdiagnose leukocytosis as a sign of infection. METHODS: In an observational study, 140 patients who underwent on - pump CABG were enrolled to find out normal values of the reference interval. WBC counts were evaluated for all of them one day before the operation, first 30 minutes of ICU entrance, after 24 hours, and 48 hours after operation. Normal values of reference intervals were calculated for each measurement by two different statistical methods. RESULTS: There were 102 men and 38 women with age average of 61 years. There was no significant difference between genders' WBC counts before operation (P = 0.151), ICU entrance (P = 0.391), 24 hours after surgery (P = 0.698), and 48 hours after surgery (P = 0.523). The mean values of WBC after surgery were higher than the normal range of reference interval and had an increasing trend in the first 48 hours after surgery. The WBC values were significantly different between pre and post operation (before operation and ICU admission (P = 0.001), ICU admission and 24 hours later (P = 0.001), 24 hours after surgery, and 48 hours after surgery (P = 0.001)). All post - operative reference values were significantly higher than the range for the general population. CONCLUSIONS: There is a significant increase in WBC count after on - pump CABG. The normal range of WBC should be revised and adjusted to prevent misinterpretation as a sign of infection.
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BACKGROUND: Regarding the role of gas entry in abdomen and cardiorespiratory effects, the ability of anesthesiologists would be challenged in laparoscopic surgeries. Considering few studies in this area and the relevance of the subject, this study was performed to compare the arterial oxygen alterations before operation in comparison with after surgery between laparoscopic cholecystectomy and ovarian cystectomy. METHODS: In this prospective cohort, 70 consecutive women aged from 20 to 60 years who were candidate for laparoscopic cholecystectomy (n = 35) and ovarian cystectomy (n = 35) with reverse (20 degrees) and direct (30 degrees) Trendelenburg positions, respectively, with ASA class I or II were enrolled. After intubation and before operation, for the first time, the arterial blood gas from radial artery in supine position was obtained for laboratory assessment. Then, the second blood sample was collected from radial artery in supine position and sent to the lab to be assessed with the same device after 30 minutes from surgery termination. The measured variables from arterial blood gas were arterial partial pressure of oxygen (PaO2) and Oxygen saturation (SpO2) alterations. RESULTS: Total PaO2 was higher in the first measurement. The higher values of PaO2 in cholecystectomy (upward) than in ovarian cystectomy (downward) were not significant in univariate (P = 0.060) and multivariate analysis (P = 0.654). Furthermore, higher values of SpO2 in cholecystectomy (upward) than in ovarian cystectomy (downward) were not significant in univariate (P = 0.412) and multivariate analysis (P = 0.984). CONCLUSIONS: In general, based on the results of this study, the values of PaO2 in cholecystectomy (upward) were not significantly higher than the values in cystectomy (downward) in laparoscopic surgeries when measured 30 minutes after surgery.
