Biochemical parameters of patients presenting for elective and urgent caesarean sections at Chris Hani Baragwanath Hospital
Nethathe, Gladness Dakalo
Introduction Maternal volume depletion at the time of caesarean section plays a role in ma- ternal and fetal outcome. Measuring uid volume status currently requires invasive monitors. It would be useful to determine biochemical measurements which would accurately determine uid volume status in these patients. We investigated the di erence in biochemical parameters of participants presenting for elective and urgent caesarean section at Chris Hani Baragwanath Hospital and made inferences about their uid volume status. We also sought to de- termine whether this difference in biochemical parameters if present could be linked to a potential difference in the intra-operative haemodynamic course as well as fetal outcome between the two groups. Method This was a prospective open-label observational cross-sectional pilot study. The sample was 54 participants, 27 elective and 27 urgent cases. Blood and urine samples were taken at the red line. Parameters from the blood samples were haematocrit, haemoglobin, sodium, urea, creatinine and plasma osmolality. Parameters from the urine samples were sodium, creatinine, osmolality and specific gravity. Intra-operatively, all participants received a standard spinal anaesthetic. Vari- ables measured intra-operatively were systolic, diastolic and mean arterial blood pressure, heart rate, highest level of block achieved as well as 1 and 5 minute Apgar scores of the newborn. The primary outcome variable was hypotension (mean arterial drop of more than 15% from the baseline). The secondary outcome variable were the Apgar scores of the infants. Results Urine specific gravity showed a trend towards statistical significance (mean, median, standard deviation for elective, urgent): 1.01, 1.010, 0.01 and 1.02, 1.015, 0.01 p = 0:06. The other biochemical parameteres displayed higher p- values. The average relative blood pressure change was -11,7% (median, standard de- viation) (-12.4, 11.1) for the elective group and -15.1% (-14.9, 15.1) for the urgent group p = 0:36. The relative blood pressure change to end point of study was -9.6% (-9, 12.7) for the elective group and -15.4% (-17, 17.6) for the urgent group p = 0:17. When comparing baseline blood pressure and heart rate measurements to the 10 minute end point measurements; 15 participants expe- rienced hypotension in the urgent group compared to 9 in the elective group p = 0:17. When comparing baseline blood pressure measurements to the av- erage at 2, 4, 6, 8, and 10 minute intervals; 13 participants from the urgent group experienced hypotension compared to 9 participants in the elective group p = 0:40. The average Apgar scores at 1 min were 8.89 (9,0.32) for the elective group and 8.37 (9,0.93) for the urgent group p = 0:01. Conclusion This was a pilot study and as such statistical signi cance between variables was not expected. However possible trends were identified to guide future investiga- tions. The higher incidence rate of hypotension in the urgent group showed such a trend towards signi cance as well as the higher urine specific gravity in the urgent group. We also noted that Apgar scores differed significantly between elective and urgent cases.