Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT04855318 |
| Other study ID # |
09.2020.158 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
|
| First received |
|
| Last updated |
|
| Start date |
January 10, 2021 |
| Est. completion date |
March 20, 2021 |
Study information
| Verified date |
June 2021 |
| Source |
Marmara University |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Observational [Patient Registry]
|
Clinical Trial Summary
The frequency of obese postoperative rhabdomyolized acute tubular necrosis (ATN) and renal
failure is also increasing. It is simply important to manage fluid. The fluid requirement
should be higher than planned. In order to learn the postoperative ATN and the development of
renal failure, 4-5 lt crystalloid fluid should be given in 2-3 times or 1.5 ml / kg / h
should be provided in the upper outlet.
According to TVA, there are no good guidelines for intraoperative fluid management in
bariatric surgery. Different intraoperative fluid management communications are used. The key
to improving outcomes from post-operative treatment is "patient directed fluid management" or
"targeted fluid management". The use of Perioperative Goal-Directed Fluid Therapy
Technologies helps the anesthesiologist closely monitor the patient and strike the delicate
balance between benefit and risk. Plethysmographic variability index monitoring (PVI-Pleth
Variability Index) is a non-invasive, automatic and continuous monitor that displays patient
fluid response, it is one of the easily applicable and easily interpreted monitoring methods.
With PVI monitoring, intraoperative hypotension and fluid need can be predicted in advance.
Plethysmographic Variability Index (PVI) is the determination of the importance of monitoring
of intraoperative volume replacement and its effect on postoperative operations.
Description:
Obesity is defined as an increase in body weight beyond requirements as a result of excessive
fat accumulation in the body and is common Obesity leads to an increase in health problems
and morbidity and mortality, as well as individual and social problems and a decrease in the
workforce. Despite sports, diet, lifestyle changes and medical treatments, the rate of
obesity continues to increase in the population. The most effective and durable treatment
option for morbid obesity is bariatric surgery. Video laparoscopic bariatric surgery (VLBS)
is recognized as the best surgical technique for morbidly obese individuals with health
complications associated with excess body fat. Despite the proven benefits of VLBS, it can
model a systemic inflammatory response. VLBS also poses an inherent risk of pneumoperitoneum
for the kidneys due to high intra-abdominal pressure, which reduces cortical capillary blood
flow by increasing renal vascular resistance. As a result, the glomerular filtration rate
(GFR) decreases and transient oliguria occurs. Acute renal failure manifested as a large
increase in creatinine levels with oliguria.
It is a preventable complication with intraoperative anesthesia management.Glomerular
filtration rate (GFR) and increased renal plasma flow cause hyperfiltration syndrome in
obesity. Adinopectin, proinflammatory cytokines, oxidative stress and pharmacological
nephrotoxicity are the mechanisms affecting acute kidney injury in obesity. Chronic renal
failure occurs as a result of a decrease in albiminuria and GFR. They are the causes of
postoperative renal failure in patients with diabetes, a history of kidney disease, using
antihypertensive drugs containing diuretics, and obese patients with a BMI greater than 50 kg
/ m2, prolonged operation time, and intraoperative hypotension.
The frequency of acute tubular necrosis (ATN) and renal failure due to postoperative
rhabdomyolysis is also increased in obese patients. Fluid management is important to prevent
this. The fluid requirement should be higher than planned. In order to prevent the
development of postoperative ATN and renal failure, 4-5 liters of crystalloid fluid should be
given in 2-3 hours or urine output above 1.5 ml / kg / h should be provided.
According to TVA, there are studies performing crystalloid fluid replacement in a wide range
of 15-40 ml / kg.
In obese patients, changes in distribution volume such as decreased hepatic blood flow,
increase in renal blood flow and glomerular filtration rate and increase in the amount of
free-flowing drug are the most important factors affecting the pharmacokinetics of drugs.
Drug doses used in these patients are recommended to be calculated according to total body
weight (TVA), ideal body weight (IVA), and lean body weight (HVA = IVA + 20%), taking into
account the lipophilic nature of the drug. For example in induction; when using high
lipophilic drugs according to YVA or IVA; moderately lipophilic For drugs, the dosage can be
increased by 20-40% and used according to the YVA.Propofol's high lipophilic properties cause
its effect to start very quickly and to be short-lived. It has been shown in many studies
that there is no usable accumulation or prolongation of propofol compared to TVA in obese
patients.
Short-acting remifentanil, one of the lipophilic synthetic opioids, can be administered
according to IVA .
There are no well-known guidelines for intraoperative fluid management in bariatric surgery.
Different intraoperative fluid management protocols are used. The key to improving outcomes
from treatment in the post-operative period is "patient directed fluid management" or
"targeted fluid management". The use of Perioperative Goal-Directed Fluid Therapy
Technologies helps the anesthesiologist to closely monitor the patient and establish the
delicate balance between benefit and risk. Plethysmographic variability index monitoring
(PVI-Pleth Variability Index) is a non-invasive, automatic and continuous monitor that
displays the fluid response of patients, and is one of the easy-to-apply and easily
interpreted monitoring methods. It has been shown that intraoperative hypotension and fluid
need can be predicted with PVI monitoring.
The aim of this study is to determine the effect of Pleth Variability Index (PVI) monitoring
on intraoperative volume replacement amount and postoperative complications in obese patients
who underwent bariatric surgery.
Patients and Methods
Patients A total of 60 obese patients who scheduled for elective bariatric surgery were
included in this single-blind prospective randomized study. Patients were required to have an
ASA physical status class 2 or 3. Exclusion criteria were as follows: severe cardiac
arrhythmia, peripheral artery disease, an ejection fraction <30%, any pulmonary pathology
preventing a respiratory volume >6 ml/kg/min on mechanical ventilation, and hepatic or renal
impairment. The study protocol was approved by the local ethics committee of Marmara
University Medical Faculty (03.01.2020- 09.2020.158). All patients provided informed consent
prior to study entry and the study was conducted in accordance with the Declaration of
Helsinki.
Study groups Patients were randomly assigned to the PVI group or control group using sealed
envelope method. Fluid management was based on PVI values in the PVI group, where a PVI value
<13% was targeted throughout the operation. Standard fluid management regimen was used for
the controls. All patients fasted for eight hours before the operation. In the operating
room, all patients were monitored for PVI; however, anesthesia team was able to see only the
PVI values of the PVI groups that would aid fluid management; whereas team was blinded to the
PVI values of the controls in whom the fluid management was done using standard approach. On
the other hand, PVI values of the controls were also recorded by another anesthesiologist
every 15 minutes.
Anesthesia management For anesthesia induction, 2 mg/kg propofol and 1μgr/kg remifentanil
were used in all patients and 0.6 mg/kg rocuronium (Esmeron vial, Schering -Plough, Istanbul,
Turkey) was used for muscle relaxation. Following endotracheal intubation, total intravenous
anesthesia with propofol and remifentanil was used. In addition to PVI, both groups were
monitored for other parameters such as heart rate (HR), noninvasive mean blood pressure
(MAB), and perfusion index (PI), and bispectral index scale (BIS). Propofol dose was adjusted
to keep BIS between 40 and 45 throughout the operation.
Fluid management Controls Following anesthesia induction, controls received crystalloid
solution at an infusion rate of 4-8 ml/kg/h for fluid maintenance. Infusion rate was adjusted
by the same anesthesiologist based on routine approach based on intraoperative assessments
such as heart rate, mean arterial pressure and urine output. In case of hypotension, which
was defined as mean arterial blood pressure <65 mmHg, crystalloid infusion was increased and
colloid infusion (Gelofusine® Melsungen, Germany) was started. In case hypotension persists,
5 mg of ephedrine was administered intravenously, and it was repeated every 5 minutes until
mean arterial blood pressure is above 65 mmHg.
PVI group Crystalloid replacement was adjusted according the PVI values, which were targeted
to be kept below 13% above 5%. Fluid maintenance was started with 2ml/kg/hour crystalloid
dose. If PVI is >13% for more than 5 minutes, a 250 ml bolus Gelofusine® was administered. If
PVI was still >13% following this, it was repeated every 5 minutes until PVI<13%. Meanwhile,
5 mg bolus ephedrine was administered to keep mean blood pressure over 65 mmHg, when
necessary. In case mean blood pressure is <65 mmHg, intravenous 5 mg ephedrine was repeated
every 5 minutes until mean blood pressure is over 65 mmHg.
Assessments Following parameters were recorded intraoperatively at 15 minutes intervals: PVI
value, heart rate, mean arterial pressure, perfusion index value. In addition, preoperative
bun, creatinine, and lactate values, perioperative use of crystalloids, colloids, blood/blood
products, and bleeding amounts, intra- and postoperative urine outputs, as well as
postoperative bun, creatinine, lactate values were recorded.
