The Effects of Vasopressors on Gastric Intramucosal pH and Gastric Mucosal - Arterial Carbon Dioxide Partial Pressure Difference in Septic Shock

Dr Sameer Taneja

Volume : VIII, Issue : IV, April - 2019

The Effects of Vasopressors on Gastric Intramucosal pH and Gastric Mucosal - Arterial Carbon Dioxide Partial Pressure Difference in Septic Shock

Dr Sameer Taneja

Abstract :

Background & Aim: Splanchnic ischemia has been implicated in the pathogenesis of sepsis and is postulated to be an important factor in the development of multi-organ failure, and resultant mortality in critically ill patients. The aim of this study was to assess the effect of vasoconstrictors on the gastric intra-mucosal pH (pHi) and difference in the gastric mucosal and arterial carbon dioxide tension (PgCO2-PaCO2 gap) in patients with septic shock using gastric tonometry. Material & Methods: . The effect of hemodynamic drug infusions on the splanchnic circulation was determined in this study by the measurement of pHi and the PgCO2-PaCO2 gap. Fifty patients diagnosed with septic shock and treated with vasopressors were subjected to six- hourly recordings of pHi and the PgCO2- PaCO2 gap using gastric tonometery and arterial blood gas analysis over a 24-hour period. Statistical analysis was undertaken to identify the vasopressor/ combination which has the least as well as the maximum deleterious effect on pHi and the PgCO2 - PaCO2 gap. A low pHi and a rising PgCO2-PaCO2 gap were indicative of inadequate tissue perfusion resulting in splanchnic ischemia. Result: Patients treated with norepinephrine or a combination of dobutamine and norepinephrine were found to have significantly higher mean pHi (p<0.001) values and lower mean PgCO2-PaCO2 gaps (p<0.001) within the specified time intervals. The mean pHi values were significantly decreased for three consecutive 6-hourly readings in the dopamine group. The PgCO2 - PaCO2 gap significantly widened over 12 hours of dopamine use but was not significantly higher than baseline at 18-hours post-initiation of the infusion. However, the mean pHi values at T1, T2 and T3 intervals were found to be significantly decreased in patients in the dopamine group in this study. Those receiving low - dose vasopressin exhibited significantly lower mean pHi values and widening of the PgCO2-PaCO2 gap (p<0.05). The use of epinephrine significantly increased the pHi at the third time interval and widened the PgCO2- PaCO2 difference. Conclusion: In this study, norepinephrine and dobutamine in combination with norepinephrine were found to exert a protective effect on the splanchnic circulation by improvement in splanchnic perfusion as manifested be an improving pHi and a decreasing PgCO2 - PaCO2 gap in patients with septic shock. The overall effect of dopamine on the splanchnic circulation could not be unequivocally established in this study. Low - dose vasopressin exacerbated gastric intramucosal acidosis and increased the PgCO2-PaCO2 gap and thereby exerted a deleterious effect on the splanchnic circulation. The use of epinephrine (>18 hours) caused splanchnic ischemia demonstrated by a decreased pHi and a progressively widened PgCO2-PaCO2 gap.