Subjects
This study was carried out in accordance with the Declaration of
Helsinki and approved by the Ethics Committee of the Harran University
(Approval Number 2019.4.20). After the approval of the hospital ethics
committee, The study was registered in the Australian New Zealand
Clinical Trials Registry (ANZCTR) (Trial Id: ACTRN12620000169943).
Patients who underwent elective laparoscopic cholecystectomy under
general anesthesia for cholelithiasis between November 2019 and February
2019 were included in this cross sectional study. Written informed
consent was obtained from all patients. Patients over the age of 18
years with written consent and with an American Anesthesiologists
Association (ASA) physical score I or II were included in the study.
Exclusion criteria; Pregnancy, acute lung disease, heart failure, body
mass index (BMI) below 18 and above 40, intraoperative bleeding over 100
ml, intraoperative inotropic support requirement, pneumoperitoneum
duration over 45 min and under 20 min. All patients were fasted for at
least 8 hours before surgery, and none of the patients received
premedication.
Anesthesia management and hemodynamic monitoringBefore general anesthesia induction, standard anesthetic monitoring was
performed with electrocardiography (ECG), peripheral O2 saturation
(SpO2), non-invasive arterial pressure (NIBP) monitoring. The MightySat
™ Rx Fingertip Pulse Oximeter (Masimo Corporation, Irvine, CA) probe was
attached preventing it from being affected by light to the upper
extremity index finger tip, where the blood pressure cuff is not
attached. Anesthesia induction was performed by the same anesthetist
with fentanyl (2 μg / kg) and propofol (2-3 mg / kg). Rocuronium bromide
0.6 mg / kg was used as a muscle relaxant. Volume controlled ventilation
was applied to the patients after intubation. Ventilator settings were
made as follows: tidal volume was 8 ml / kg according to ideal body
weight, positive end-tidal pressure (PEEP) was 5 cmH2O, inspirium
expirium ratio was 1: 2, respiratory rate was 11-14 breaths / minute and
then the end-tidal carbon dioxide pressure (EtCO2) was adjusted to be
35-45 mmHg. Sevoflurane and iv remifentanil (0.25-0.5 μg / kg / min)
infusion was used in the mixture of air and oxygen for maintenance of
anesthesia.
Study design Data were collected after anesthesia induction in all patients. In
order to minimize the effect of vasomotor tone, any stimulation to the
patients was avoided up to 5 minutes before the data was collected. PVI
and SpHg data were recorded by the same anesthesiologist in 6
pre-determined times in the end-expiratory phase.
T0 = basal value after insufflation
T1 = 5th minute of insufflation
T2: 10th minute of insufflation
T3: 15th minute of insufflation
T4 = 5 minutes before desufflation
T5 = 2 minutes after desufflation
Systolic blood pressure (SBP), diastolic blood pressure (DBP), heart
rate (HR), oxygen saturation (SpO2), EtCO2 values were recorded in the
same time frames. In addition, body mass index, operation duration and
pneumoperitoneum duration of the patients were recorded. 8 ml / kg
crystalloid solution was given to patients before anesthesia induction
in order to prevent sudden blood pressure decrease that may develop in
patients as a result of anesthesia induction, thus minimizing the impact
of PVI and SpHb values. Crystalloid infusion continued at the rate of 4
ml / kg / h throughout the operation.