Prevalence and Risk Factors of Hypoxemia after Coronary Artery Bypass Grafting: The Time to Change Our Conceptions.

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.

Effect of Hypoxemia in the Determination of Short-Term Prognosis of Coronary Artery Bypass Graft Patients: A Prospective Study.

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.

Thoracic Kidney: Extremely Rare State of Aberrant Kidney.

The thorax is the rarest place among all forms of renal ectopia. We report a rare case of an unacquired thoracic kidney. Only about 200 cases of the thoracic kidney have ever been reported in medical literature worldwide. In this paper we present the rarest form of nontraumatic nonhernia associated, truly ectopic thoracic kidney. The differential diagnosis and management options and classification of this rare form of aberrant kidney are discussed.

Acute Respiratory Distress Syndrome diagnosis after coronary artery bypass: comparison between diagnostic criteria and clinical picture.

Acute Respiratory Distress Syndrome (ARDS) is a potential complication of cardiac surgery, given that patients undergoing CABG frequently have hypoxemia and pulmonary dysfunction during initial hours after surgery. Thus, ARDS criteria in these patients are more likely to be positive while these criteria may not match the patient`s clinical picture. We aimed to investigate frequency of rapid onset hypoxemia in Pressure of Arterial Oxygen to Fractional Inspired Oxygen Concentration (PaO2/FiO2) less than 200 and diffuse pulmonary infiltrates as two diagnostic criteria forwards and compared these criteria with the clinical picture of the patients after Coronary Artery Bypass Graft (CABG) in this study. The study was prospective case series which carried out in about six months. All patients admitted to intensive care unit of Tehran Heart Center, who had undergone CABG on cardiopulmonary pump (CPB) recruited in the study. After considering inclusion criteria, age, sex, duration of intubation, arterial blood gas and chest radiography, on 24 hours and 48 hours after admission to the ICU were recorded. Then, patients with rapid onset of hypoxemia (PaO2/FiO2≤200mmHg) and diffuse pulmonary infiltrates and without sign or symptoms of obvious heart failure (probable positive ARDS cases) criteria were recorded and comparison between these probable positive cases with clinician`s clinical diagnosis (blinded to the study) was performed. In this study, a total of 300 patients after on-pump coronary artery bypass surgery were included. Postoperatively, 2 (0.66 %) in the 24 hours and 4 (1.33%) patients in 48 hours after surgery were positive for the two ARDS criteria according to the checklists, but; nobody had saved persistently ARDS criteria persistently during 48 hours after surgery. At the same time, clinician did not report any case of ARDS among 300 patients. In this study patients with ARDS criteria had no significant differences in age (P.value=0.937) and sex (P.value=0.533). Duration of intubation in patients with ARDS (14.26 ± 4.25 hours) in the first 48 hours was higher but not statistically different from the group without ARDS (11.60 ± 5.45 hours) (P.value=0.236). ARDS diagnosis based on rapid onset of hypoxemia (PaO2/FiO2≤200 mmHg) and diffuse pulmonary infiltrates and without signs or symptoms of obvious heart failure criteria in patients undergoing CABG could lead to overdiagnosis or misdiagnosis in less than 24 hours follow up. We recommend following patients for more than 24 hours and revise the current ARDS criteria for CABG patients.

Hospital-acquired pneumonia in patients undergoing coronary artery bypass graft; comparison of the center for disease control clinical criteria with physicians' judgment.

BACKGROUND: Following coronary artery bypass graft (CABG), patients are at high risk (3.2%-8.3%) for developing hospital-acquired pneumonia (HAP) with mortality rate of 24% to 50%. Some of routine features in patients undergoing CABG are similar to clinical criteria of Center of Disease Control (CDC) for diagnosis of pneumonia. This may lead to over-diagnosis of pneumonia in these patients. OBJECTIVES: This study aimed to assess the frequency of CDC criteria for diagnosis of pneumonia in patients undergoing CABG. PATIENTS AND METHODS: This study was performed on CABG candidates admitted to post cardiac surgery Intensive Care Unit (ICU) in a six-month period. Patient's records, Chest-X-Ray, and Laboratory tests were assessed for PNU1-CDC criteria for HAP diagnosis. At the same time, a physician who was unaware of the study protocol assessed the clinical diagnosis. Then the results were compared with CDC criteria-based diagnosis. RESULTS: Of total 300 patients, 9 (3%) met CDC criteria for diagnosis of pneumonia while none of the cases were diagnosed as HAP according to the physicians' clinical diagnosis. All nine patients were discharged with proper general condition and no need of antibiotic therapy. This study showed that loss of consciousness, tachypnea, dyspnea, PaO2 < 60 mm Hg, PaO2/FiO2 < 240, and local infiltration in 24 hours of operation were misleading features of CDC criteria, which were not considered in physicians' clinical judgment to establish the diagnosis. CONCLUSIONS: Our findings suggest that in Post-CABG patients, physicians could judge the occurrence of HAP more accurately in comparison to making the diagnosis based on CDC criteria alone. Expert physician may intentionally do not take some of these criteria into account according the patients' course of disease. Therefore, it is suggested that the value of these criteria in special group of patients like those undergoing CABG should be re-evaluated.

Fixed Cut-Off for FEV1/FEV6 and FEV6 in Detection of Obstructive and Restrictive Patterns.

BACKGROUND: Chronic obstructive pulmonary diseases (COPD) have been defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) as irreversible conditions which are diagnosed by fixed cut-off points of FEV1/FVC. OBJECTIVE: The aim of this study was to determine the cut-off points for FEV1/FEV6 ratio and FEV6 as alternatives for FEV1/FVC and FVC in detection of airway obstruction and lung restriction, respectively. MATERIALS AND METHODS: A total of 318 Spiro metric examinations of subjects referred to Shariati hospital were analyzed. A subject was considered to have obstruction if FEV1/FVC was lower than 70%. The restriction was defined as FVC < 80% in the absence of obstruction. The Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of FEV1/FEV6 and FEV6 were calculated. RESULTS: This study shows that the current cut-off points used to detect obstruction and restriction can be replaced by FEV1/FEV6 < 71% and FEV6 < 83%, respectively. FEV1/FEV6 had sensitivity of 95.5% and specificity of 99.4%; the PPV and NPVs were 99.3% and 96.3%. The prevalence of obstruction was 49.4%. For restrictive pattern, FEV6 had sensitivity of 93%, specificity of 79.5% with PPV of 18% and NPV of 99.5%. The prevalence of restriction was 6.3%. CONCLUSIONS: The FEV1/FEV6 ratio can be used as a valid surrogate for FEV1/FVC in the diagnosis of airway obstruction, especially for screening purposes in high-risk populations for COPD. Moreover, FEV6 is an acceptable alternative for FVC in detection of restrictive pattern.

Prevalence of tuberculosis in patients with anthracosis: study on 150 subjects.

BACKGROUND: A probable concordance and association between pulmonary tuberculosis and anthracosis was observed in the published literature. We conducted this study to evaluate the clinical and radiologic characteristics of patients with bronchoscopic evidence of anthracosis as well as the prevalence of pulmonary tuberculosis in patients with anthracosis. METHODS: Included in the study were 150 consecutive patients with evidence of anthracosis as evidenced by bronchoscopy. Pulmonary tuberculosis diagnostic work up which included bronchoalveolar lavage, sputum smears and cultures, or histologic examination of lung biopsies was performed on all patients. Patients' clinical, pathological, and radiological findings were also recorded and analyzed. RESULTS: A total of 88 men and 62 women, ranging in age from 42 to 92 years were included in the study. Dyspnea (38.7%) and productive cough (35.3%) were among the most common chief complaints. The abnormal bronchoscopic findings were seen most frequently in the right middle lobe bronchus. In 42 patients pulmonary tuberculosis was confirmed either bacteriologically (n = 32) or histologically (n = 10). CT scans of 26 patients were examined, of which the most frequent findings were consolidation and a reticular pattern. Pleural involvement was observed in 14 patients. CONCLUSION: Prevalence of pulmonary tuberculosis was higher among those with bronchial stenosis (P < 0.05). These findings have suggested that bronchial anthracosis, especially cases of localized anthracosis, in patients with bronchial stenosis and in those without a history of smoking or occupational exposure may be caused by tuberculosis.

A New Method for Extubation: Comparison between Conventional and New Methods.

BACKGROUND: Extubation is associated with the risk of complications such as accumulated secretion above the endotracheal tube cuff, eventual atelectasia following a reduction in pulmonary volumes because of a lack of physiological positive end expiratory pressure, and intra-tracheal suction. In order to reduce these complications, and, based on basic physiological principles, a new practical extubation method is presented in this article. METHODS: The study was designed as a six-month prospective cross-sectional clinical trial. Two hundred fifty-seven patients undergoing coronary artery bypass grafting (CABG) were divided into two groups based on their scheduled surgery time. The first group underwent the conventional extubation method, while the other group was extubated according to a new described method. Arterial blood gas (ABG) analysis results before and after extubation were compared between the two groups to find the effect of the extubation method on the ABG parameters and the oxygenation profile. RESULTS: In all time intervals, the partial pressure of oxygen in arterial blood / fraction of inspired oxygen (PaO(2)/FiO(2)) ratio in the new method group patients was improved compared to that in the conventional method; some differences, like PaO(2)/FiO(2) four hours after extubation, were statistically significant, however (p value=0.0063). CONCLUSION: The new extubation method improved some respiratory parameters and thus attenuated oxygenation complications and amplified oxygenation after extubation.

Logistic regression model for prediction of airway reversibility using peak expiratory flow.

BACKGROUND: Using peak expiratory flow (PEF) as an alternative to spirometry parameters (FEV1 and FVC), for detection of airway reversibility in diseases with airflow limitation is challenging. We developed logistic regression (LR) model to discriminate bronchodilator responsiveness (BDR) and then compared the results of models with a performance of >18%, >20%, and >22% increase in ΔPEF% (PEF change relative to baseline), as a predictor for bronchodilator responsiveness (BDR). MATERIALS AND METHODS: PEF measurements of pre-bronchodilator, post-bronchodilator and ΔPEF% of 90 patients with asthma (44) and chronic obstructive pulmonary disease (46) were used as inputs of model and the output was presence or absence of the BDR. RESULTS: Although ΔPEF% was a poor discriminator, LR model could improve the accuracy of BDR. Sensitivity, specificity, positive predictive value, and negative predictive value of LR were 68.89%, 67.27%, 71.43%, and 78.72%, respectively. CONCLUSION: The LR is a reliable method that can be used clinically to predict BDR based on PEF measurements.

Pulmonary function and methacholine challenge tests in patients with ulcerative colitis.

BACKGROUND: Ulcerative colitis is an inflammatory chronic disease which is believed to be a multi organ condition. The prevalence of ulcerative colitis is reportedly increasing in Iran presenting with the same clinical characteristics as in developing countries. Pulmonary manifestations of ulcerative colitis are increasingly reported. In this study, we investigated the incidence of bronchial hyper-responsiveness (BHR) in ulcerative colitis (UC) patients. MATERIALS AND METHODS: Fifty-one UC patients with definite diagnosis referred to Shariati Hospital, Tehran, Iran, were selected to be evaluated with methacholine challenge test from October 2010 to October 2011. Patients were compared for their methacholine test outcome and its association with age, sex, diagnosis time, and disease activity. RESULTS: The median age was 41 (range 15 to 65) years. The median time of diagnosis was 7 (range <1 to 16) years. Forty-five percent were females, 18% had active disease and 13% had comorbidity. Nine percent of patients with UC had abnormal PFT in our study. Three cases (5%) had bronchial hyper-responsiveness that was not correlated with sex, age, time of diagnosis, or disease activity. CONCLUSION: A small number of ulcerative colitis patients in our study had disturbed pulmonary function test which is in concord with the findings of other studies. However, higher rates of bronchial hyper-responsiveness have been reported in other studies. Confounding factors like cigarette smoking and medications, which were negative or minimal in our study, may influence the results.

Testicular masses in a man with a plausible sarcoidosis.

Genitourinary involvement with sarcoidosis is very rare. The objective of this report was to present a case of a patient with testicular swelling. The patient was an infertile 42-year-old man with bilateral testicular swelling. Semen analysis in the past 10 years revealed no abnormality; however, gradually he became azoospermic in 3 years. A diagnosis of sarcoidosis made on the basis of hilar and mediastinal lymphadenopathy in chest CT scan was confirmed through testicular and epididymal biopsy. Testicular masses vanished after administering steroids, and azoospermia recovered. To conclude, although genitourinary sarcoidosis is rare, it must be kept in mind in patients with confirmed sarcoidosis.