The Value of Central Venous-arterial Carbon Dioxide Difference

A Research of Central Venous-arterial Carbon Dioxide Difference Has Guiding Significance for Severely Burn Patients in Liquid Resuscitation During Early Escharectomy

By observing the changes of Central venous-arterial partial pressure difference of carbon dioxide [P (v-a) CO2] in liquid resuscitation during early escharectomy in patients with large-scale burns, We investigate the effect of P (v-a) CO2 on postoperative tissue perfusion and oxygenation in order to seek a more effective intergrated target plan of liquid resuscitation for burn patients.

Objective: By observing the changes of Central venous-arterial partial pressure difference of carbon dioxide [P (v-a) CO2] in liquid resuscitation during early escharectomy in patients with large-scale burns, We investigate the effect of P (v-a) CO2 on postoperative tissue perfusion and oxygenation in order to seek a more effective intergrated target plan of liquid resuscitation for burn patients.

Methods: a prospective observational study was conducted on 145 patients with extensive burns admitted to surgical intensive care unit（SICU）of Guangzhou Red Cross hospital from January 2016 to December 2019. All patients received hemodynamic monitoring and goal-directed fluid therapy, patients with central venous oxygen saturation (ScvO2)< 70% were excluded. Patients were divided into the following groups according to the changing trend of Pcv-aCO2 between T base (before induction) and T 0h (after surgery) : group 1 (H-H) : Pcv-aCO2≥6mmHg between T base and T 0h. Group 2 (L-H) : Pcv-aco2< 6mmHg at T base and≥6mmHg at T 0h; Group 3 (H-L) : Pcv-aCO2≥6mmHg at T base and < 6mmHg at T 0h. Group 4( L-L) : Pcv-aCO2 < 6mmHg between T base and T0h.Postoperative basic physiological indicators such as heart rate（HR）, blood pressure, central venous pressure (CVP), cardiac output index (CI), Pcv-aCO2 and lactic acid were recorded at 0 and 18 hours after surgery. Oxygen dynamic indicators such as oxygen delivery index (DO2I), oxygen consumption index (VO2I), oxygen uptake rate (O2ER) and so on were calculated. Pearson correlation analysis was used to evaluate the correlation between Pcv-aCO2 and CI. The change of tissue perfusion and oxygenation with different levels of Pcv-aCO2 after fluid resuscitation were analyzed.

Inclusion Criteria:

1. ASAI-II
2. New York Heart Association classification of cardiac function I-II
3. Estimated time of operation<3h
4. The circulatory system of patients is stable after thrapy：CVP8～12 mmHg；MAP≥65 mmHg；urine volume>0.5m1/kg/ h；ScvO2：≥70％。

Exclusion Criteria:

1. Anesthetic drug allergy or contraindication
2. Patients with cardiopulmonary system disease、cardiopulmonary function abnormality、severe inhalation injuryand severe visceral injury.