A Comparison of Occupational CO Levels, HbCO, and Lung Functions Between Grill and Non-grill Street Vendors

BACKGROUND

There is a surge increase in grills-fast food outlet in the urban areas that plays an essential role in producing air pollution. Chronic accumulation of carbon monoxide might affect the airway and destroy alveolus as well as correlated with the disturbance of lung function.

OBJECTIVE

The purpose of this study is to compare the occupational CO levels, HbCO, and lung functions between grill and non-grill street vendors.

METHODS

This was an observational analytic study with a case-control design. The subjects were grill street vendors and non-grill street vendors in Medan city who fulfilled several inclusion criteria. The questionnaire was used to determine some characteristics, while smokerlyzer, and ELISA for expiration CO level and blood CO level, spirometer was used to determining lung function. Logistic regression was performed with p-value < 0.05 considered to be significant using SPSS ver 24.0.

RESULTS

A total of 50 subjects enrolled into this study with the majority of subjects in the case group were in red (40%) zone in CO exhaled test with the results in pulmonary function test, predominantly restrictive (56%) and mixed-type (40%) with the mean value of HbCO was 486.16 (ng/mL). Meanwhile, the majority of subjects were green zone with mixed type of lung function disturbance in the control group with 540.15 (ng/mL) as HBCO mean value. Grilled street vendors have a higher level of exhaled CO level (p- value: 0.03) without significant difference in HbCO and lung functions (p-value > 0.05). Age, smoking status, HbCO, and lung function did not significantly affect the CO level (p-value: 0.05).

CONCLUSION

There was a significant difference in exhaled CO level between grill-and non-grill street vendors without significant difference in HbCO and lung functions.

Detection of blood volumes and haemoglobin mass by means of CO re-breathing and indocyanine green and sodium fluorescein injections

The main aim of the present study was to quantify the magnitude of differences introduced when estimating a given blood volume compartment (e.g. plasma volume) through the direct determination of another compartment (e.g. red cell volume) by multiplication of venous haematocrit and/or haemoglobin concentration. However, since whole body haematocrit is higher than venous haematocrit such an approach might comprise certain errors. To test this experimentally, four different methods for detecting blood volumes and haemoglobin mass (Hb_mass) were compared, namely the carbon monoxide (CO) re-breathing (for Hb_mass), the indocyanine green (ICG; for plasma volume [PV]) and the sodium fluorescein (SoF; for red blood cell volume [RBCV]) methods. No difference between ICG and CO re-breathing derived PV could be established when a whole body/venous haematocrit correction factor of 0.91 was applied (p = 0.11, r = 0.43, mean difference -340 ± 612 mL). In contrast, when comparing RBCV derived by the CO re-breathing and the SoF method, the SoF method revealed lower RBCV values as compared to the CO re-breathing method (p < 0.05, r = 0.95, mean difference -728 ± 184 mL). However, compared to the ICG and the SoF methods, the typical error (%TE) and hence reliability of the CO re-breathing method was lower for all measured parameters. Therefore, estimating blood volume compartments by the direct assessment of another compartment can be considered a suitable approach. The CO re-breathing method proved accurate in determining the induced phlebotomy and is at the same time judged easier to perform than any of the other methods.