BACKGOUND The high mortality due to circulatory shock necessitate the need for early biomarkers to assess tissue perfusion which could provide important information about prognosis and help guide resuscitation efforts. The PCO 2 gap is difference between partial pressure of CO 2 in venous blood (PvCO 2 ) and arterial blood (PaCO2)as blood lactate and venous oxygen saturation (SvO2) are commonly used but it has many limitations .Raised pCO2 gap has been recognized as a marker of poor outcome during circulatory shock and it should therefore be part of our clinical evaluation to guide fluid administration in the early phases of resuscitation. An increase in pCO2 gap(PcvCO2- PaCO2) >6mm of Hg suggests a shock that may be responsive to fluid resuscitation. We aim to calculate pCO2 gap in postoperative high risk patients as it will aide as a guide to adequacy of resuscitation and outcome of such patients. Aims and objectives Primary objective 1.To access the correlation of ï„pCO 2 with adequacy of fluid resuscitation in postoperative high risk surgical patients 2. To access correlation of pCO 2 gap (central venous-arterial carbon dioxide difference) with fluid resuscitation in postoperative high risk surgical patients Secondary objectives 1. Comparing ï„pCO2 gap with ï„serum lactate levels, ï„SvO2 levels 2. Correlation of ï„pCO 2 with 28 day mortality in postoperative high risk surgical patients Patients and Methods
In post operative period following high risk surgery, patients who are in shock and mechanical ventilation, arterial blood gas will be done to evaluate pCO 2 , lactate, pO 2 , and simultaneous central venous sample to evaluate the same will be done at onset of shock, following fluid resuscitation, 2hrs, 6 hrs, 24 hours. The PCO 2 gap will be calculated by the difference between central venous partial pressure of carbon dioxide and arterial partial pressure of carbon dioxide. , routine laboratory tests were obtained by intermittent blood sampling immediately after admission At ICU admission, data on demographics (age, sex, weight), type of surgical procedure, Simplified Acute Physiology Score (SAPS) II, and inotropic support will be recorded in all patients. The study population will be divided into two groups according to fluid responsiveness. The pCO2, Central and arterial CO2 gaps, SVO2 and lactate level will be accessed pre and post fluid resuscitation. Postoperative complications will be defined in accordance with defined criteria until hospital discharge or death as follows: postoperative sepsis (pneumonia, intraperitoneal abscess, wound infection, peritonitis and urinary tract infection), acute renal and cardiac failures, postoperative hemorrhage, ischemic events, and postoperative mortality. Patients will be followed up till hospital discharge or death. |