الفهرس 
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Abstract
Fluid status assessment and management during perioperative period in cardiac surgery is considered as a clinical challenge. The key to anaesthesia in CABG is to maintain adequate CO beside the adequate myocardial oxygen supply and demand balance. Consequently it is particularly important to control HR, maintain stability of blood pressure, assess and regulate the blood volume.
Several variables of preload and fluid responsiveness can be used to judge fluid therapy in critically ill and injured patients including:
1- Cardiac filling pressures as (CVP, PAP and PCWP)
2- Static volumic variables as (FAC%, GEF%, LVEDA and index)
3- Dynamic variables of fluid response as (SPV, PPV, SVV, LVSVI and ∆V peak).
Each variable has its own reliability (sensitivity and specificity) for prediction of fluid responsiveness; using correlation study between % of change of each parameter and % of change in intravascular volume (LVSVI) after fluid loading, beside the use of ROC curves.
The use of flow directed PAC into clinical practice is one of the most important and popular advances in the field of cardiac anaesthesia and intensive care; However the recent introduction of TEE in the OR and ICU represented a great advance in cardiovascular monitoring. This technique allows direct and fast visualization of the structural anatomy of the heart and large vessels and contributes to haemodynamic and functional assessment of the cardiovascular system.
TEE is perhaps the most non-invasive and best studied method of cardiac imaging; as many researches prefer using TEE superior to PAC in diagnosing acute haemodynamic changes.
The aim of this study was to evaluate the efficiency and efficacy of TEE versus PAC in prediction of fluid responsiveness in patients underwent open heart surgery for CABG; through continuous monitoring and follow up of haemodynamic beside static and dynamic indicators of fluid responsiveness measured by TEE and/or PAC from induction till six hours postoperative.
This study was carried out on randomly selected sixty adult patients ASA (American Society of Anaesthiology) physical status II/III of both sexes, admitted to Alexandria Main University Hospitals in Cardiothoracic Surgical Department to perform open heart surgery for CABG under general anaesthesia.
Patients were randomly allocated into two equal groups 30 patients each, they were chosen by closed envelop method labeled as group I and II
group I: (PAC group) in this group of patients; the assessment of fluid responsiveness done using PAC (Swan-Ganz).
group II: (TEE group) fluid responsiveness was assessed in this group of patients using TEE.
With the following exclusion criteria:
1- Patients with severe tricuspid insufficiency.
2- Patients with severe pulmonary hypertension or tight pulmonary stenosis.
3- Low CO (Global Ejection Fraction GEF <35%).
4- History of pulmonary veno-occulsive diseases (embolism or fibrosis).
5- Patients with right side heart failure (hugely dilated right atrium or right ventricle).
6- History of esophageal pathology precluding the use of TEE (stricture, mass, diverticulum).
7- Duration of bypass above 120 min.
8- Morbid obesity (body mass index BMI > 40).
9- Peri-operative mortality.
10- Significant arrhythmias (arrhythmias with haemodynamic instability); and the use of pace maker.
Measurements
1- HR
2- IMABP in all patients
3- Urine volume, total fluid input and output.
4- Cardiac filling pressures including: (CVP in all patients, PAP and PCWP in group I only)
5- Static volumic variables including (GEF%, LVEDA, LVEDAI and FAC % all in group II only).
6- Dynamic variables of fluid responsiveness including (PPV, SPV, SVV, LVSVI in all patients and ∆V peak in group II only).
All above haemodynamic and functional parameters of fluid response were done at the following intervals:
- After induction (baseline).
- 20 min after induction (after PAC or TEE insertion).
- 30 min after induction (after 1st VLS).
- 40 min after induction (after 2nd VLS).
- At the end of surgery.
- (2 and 6 hours) after surgery.
Other operative data in all patients include:
- Duration of surgery/min.
- Duration of anaesthesia/min.
- CPB time/min.
- ACC time/min.
- Intraoperative complications.
- DSB, the need for inotropes and vasodilators; with their dose and duration.
- Presence of ischemic ECG changes.
The result of the present study showed that:
There were no significant statistically differences between the two studied groups as regards the changes in HR and IMABP from induction till 6 hours after surgery. However; significant increase in IMABP and significant decrease in HR were observed from baseline value after each VLS in both groups.
No significant differences were found between the two studied groups as regard the changes in total fluid input, output and urine volume during operative and postoperative periods. However; significant raise in the previous parameters were detected from baseline value after each VLS in both groups.
There were significant increase in CVP readings after fluid loading as compared to baseline value in the two groups of the study, but no statistically significant differences were found between the two groups during operative and postoperative periods regarding the same variable.
Also there were significant increases in mean PAP and PCWP from baseline value after each VLS in group I only using PAC.
from this study it was found that; there were no significant statistically difference between the two studied groups regarding the changes in SPV, PPV and SVV from induction till 6 hours after surgery; However significant decrease from baseline value were observed in such indices after each VLS.
No significant difference was found between the two studied groups as regard changes in LVSVI from insertion of PAC and/or TEE till 6 hours after surgery, but significant increase from baseline value was observed after each VLS.
There were significant increases in LVEDA and LVEDAI from baseline value after each VLS in group II only using TEE.
But insignificant increase in the percentage of GEF and FAC were observed in the same group (II) during the similar periods of the study.
There was a significant decrease as regard changes in ∆V peak were observed after each VLS relative to baseline value in group II only using TEE.
There was a significant tight linear correlation between % of change in (∆V peak and LVEDAI) after 2nd VLS and % of change in LVSVI after fluid loading (2nd VLS).
Moreover; % of change in the following parameters (IMABP, PPV, SVV) also correlate significantly with % of change in LVSVI after fluid loading (2nd VLS), but less than that of (∆V peak and LVEDAI).
On the other hand, % of change in (SPV, CVP, PAP and PCWP) didn’t correlate significantly with % of change in LVSVI induced by fluid loading after 2nd VLS.
Actually by using ROC curves; it was found that; (∆V peak and LVEDAI) detected by TEE had the greatest sensitivity and specificity among other parameters of fluid response. So such variables were the most reliable in the present study.
Followed by the following variables (IMABP, SPV, PPV and SVV), which had less sensitivity and specificity than (∆V peak and LVEDAI). So they were less reliable indices.
Lastly filling pressures including (CVP, PAP and PCWP) had the least sensitivity and specificity among other variables used for prediction of response to fluid administration, with poor reliability.
from this study it was found that; there were no significant statistically difference between the two studied groups regarding CPB time, ACC time, duration of surgery and anaesthesia.
Also no significant statistically differences between the two studied groups as regards inotropes and vasodilators used during surgery in addition to occurrence of intraoperative complications.
A unique score was performed in this study; based on % of change of each of the eleven selected parameter of fluid response after 2nd VLS relative to baseline value among responders and non-responders of each variable, the responders (R) took score = 1, while non-responders (NR) took score = 0.
This score composed of eleven variables; nine in group I, which included (HR, IMABP, CVP, LVSVI, SPV, PPV, SVV, PAP and PCWP) and nine parameters in group II which included (HR, IMABP, CVP, LVSVI, SPV, PPV, SVV, ∆V peak and LVEDAI).
The response to VLS was considered positive if:
1- HR was decreased about 15% of base line value.
1- IMABP was increased about 15% of base line value.
2- CVP, PAP and PAOP were increased about 15% base line value = 1st reading after insertion.
3- LVEDAI was increased > 15% of base line value = 1st reading after introduction of TEE.
4- PPV and SPV were decreased about 10% after VLS for automatically measured and about 13% for manually measured PPV.
5- SVV was decreased about 9.5% after VLS at PEEP 5 mmHg and about 14% at PEEP 10 mmHg.
6- ∆V (peak) is decreased ≥ 12% of baseline value = 1st reading after introduction of TEE.
7- LVSVI is increased ≥ 15% of baseline value (1st reading after insertion of PAC/TEE).
The total (highest) score was nine and such score enables the researcher to observe changes in all selected parameters together after fluid loading in the same patient, weather in group I or in group II.