Clinical Trial Details
— Status: Withdrawn
Administrative data
| NCT number |
NCT05016076 |
| Other study ID # |
JIRB-N202101039 |
| Secondary ID |
|
| Status |
Withdrawn |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
May 2022 |
| Est. completion date |
August 2023 |
Study information
| Verified date |
May 2022 |
| Source |
Taipei Medical University Shuang Ho Hospital |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
The main objective of this study is to investigate the optimal anesthesia for obese patients
undergoing bariatric surgery in the strategies of positive pulmonary ventilation, tracheal
intubation technique, hemodynamic monitoring, and postoperative nausea and vomiting (PONV)
prophylaxis, as the followed:
1. To evaluate the effectiveness and adverse effect of intravenous dexamethasone for PONV
prophylaxis
2. To determine the safe inspiratory pressure to prevent the occurrence of gastric
insufflation during facemask ventilation using point-of-care ultrasonography of antrum
3. To compare the effectiveness and safety between video intubating stylet and video
laryngoscope in the placement of tracheal tubes
4. To apply minimally invasive CO monitors in guiding goal-directed hemodynamic therapy and
assess its impact on major complications and postoperative recovery
Description:
Substudy 1: An evaluation of the effect of intravenous dexamethasone on postoperative nausea
and vomiting
At the operating room, participants will be initially placed in a ramped position and then
moved into a reverse Trendelenburg position to achieve a 30-degree incline of the thorax
before preoxygenation. Each participant will be randomly assigned 1:1, stratified by presence
of diabetes mellitus, to one of each of the following two interventions: dexamethasone (8 mg
intravenously) and placebo (0.9% sodium chloride). The envelopes of group allocation will be
opened just before the induction of general anesthesia.
After preoxygenation using facemask with pure oxygen 10 l·min-1 until end-tidal fractional
oxygen concentration in the expired air (EtO2) ≥ 80%, general anesthesia will be induced with
propofol 1.5-2.0 mg·kg-1 ideal body weight and fentanyl 1-2 μg·kg-1 total body weight.
Tracheal intubation will be facilitated with rocuronium 0.8-1.0 mg·kg-1 ideal body weight.
After induction, a radial artery catheterization will be performed for continuous monitoring
of arterial pressure and measurement of serum glucose. In the designated patients, 8 mg of
dexamethasone or placebo will be given intravenously within 10 minutes after the induction of
anesthesia. Anesthesia will be maintained with 2-3 vol% sevoflurane and 60% oxygen in
nitrogen, whereas the fraction of inspired oxygen (FiO2) 0.8-1.0 will be used during
pneumoperitoneum to ensure oxygen saturation higher than 92%. If the value of surgical pleth
index (CARESCAPE B650 Monitor, GE Healthcare, Chicago, IL, USA) is more than 50 or heart rate
or blood pressure increases by more than 20% from baseline values during surgery, an
intravenous bolus of fentanyl 25 or 50 μg will be given. Besides, the concentration of
sevoflurane can be adjusted as clinically appropriate.
After surgery, all participants will receive supplemental oxygen, and pain will be relieved
with ketorolac 15 to 30 mg. The need for postoperative opioids will be at the discretion of
the anesthesiologist, and the dose will be adjusted according to clinical needs. Participants
who request rescue antiemetic therapy or who have an emetic episode will be given droperidol
1.25 mg. If symptoms persist, metoclopramide 10 mg will be administered.
Primary outcome is the incidence of PONV, which includes any nausea, emetic episodes
(retching or vomiting), or both during the first 24 postoperative hour. At the 2nd and 24th
postoperative hours, trained investigators who are blinded to the group allocation will
record the number of emetic episodes, the time each one occurs, and self-reported worst
nausea episode during the preceding duration on an 11-point scale (0: no nausea and 10: the
most severe nausea).
Substudy 2: An investigation of the threshold inspiratory pressure for gastric insufflation
using ultrasonography of gastric antrum
The investigators will measure the antral area of each participant lying in supine position
on the operating table, using a portable ultrasound device (LOGIQ™, GE Healthcare, Chicago,
IL, USA, fitted with a 1.5 to 5.0 MHz convex transducer). The investigators will determine
the longitudinal (D1) and anteroposterior (D2) diameters of the cross-section of antrum in
the sagittal plane passing through abdominal aorta.50 To obtain a standardized scanning
level, the aorta and left lobe of the liver are employed as internal landmarks. The relaxed
diameters of the antrum are measured between antral contractions. The area of gastric antrum
is calculated using the formula: antral area = D1×D2×π / 4. In addition, the gastric fluid
volume will be calculated with a validated model based on the cross-sectional area of the
gastric antrum, described previously.51 Participants will be randomized into one of the four
groups defined by the applied inspiratory pressure (10, 15, 20, or 25 cmH2O) using blocked
randomization. During induction of anesthesia, normal saline 20 ml will be immediately
infused after the administration of rocuronium 0.8-1.0 mg·kg-1 ideal body weight.52 After
loss of eyelash reflex, a Guedel oropharyngeal airway (Biçakcilar, Istanbul, Turkey) will be
placed into the oral cavity to assure adequate mouth opening. A facemask will be applied
firmly to the patient's face to ensure an adequate seal. A two-handed head-tilt jaw-thrust
maneuver will be performed to establish an open airway. Once apnea determined by end-tidal
capnography occurs, a mechanical ventilation with the assigned peak inspiratory pressure will
be initiated. The pressure-controlled mode will be used with an inspiratory-to-expiratory
ratio of 1:2 and no positive end-expiratory pressure (PEEP), at a frequency of 15
breath·min-1 and with 100% oxygen, by the ventilator (Carestation 620, Datex-Ohmeda, Inc.,
Madison, WI, USA).53 Real-time ultrasonography of the antrum will be performed by the same
anesthesiologist who performs the preoperative ultrasonography. Another anesthetist will
perform continuous auscultation over epigastric area. The investigators performing
ultrasonography and auscultation are blinded one to another regarding the detection of
gastric insufflation and the inspiratory pressure of pressure-controlled ventilation. The
ultrasonography screen will be concealed from the anesthetist performing the auscultation.
Facemask ventilation will be continued for 2 min. The trachea will be thereafter intubated,
and the antral area will be measured again.
Primary outcome is the episode of gastric insufflation. The ultrasonographic diagnosis of
gastric insufflation is defined as the presence of an acoustic shadow phenomenon and/or a
comet-tail artifact into the antrum.14 A typical whoosh sound with gurgling while
auscultating over the epigastrium defines the diagnosis of gastric insufflation by
auscultation method.54
Substudy 3: A comparison of video intubation stylet and video laryngoscope in tracheal
intubation
Eligible participants will be randomly allocated 1:1:1, stratified by body mass index > 50
kg·m-2, to group 1 (video intubating stylet), group 2 (video laryngoscopy), or group 3
(direct laryngoscopy). Tracheal intubation will be performed by experienced attending
anesthesiologists who have performed at least 100 cases each with Trachway® video intubating
stylet, GlideScope® video laryngoscopy, and Macintosh direct laryngoscopy. The
anesthesiologist performing tracheal intubation is blinded to all preoperative evaluations.
In group 1, a tracheal tube (ConvaTec, Berkshire, England, UK) in appropriate sizes is
preloaded over the Trachway® video intubating stylet (TVI-4050, Markstein Sichtec Medical
Corp, Taichung, Taiwan), which is introduced into oral cavity to visualize the epiglottis and
guided to glottis via a monitor after full neuromuscular blockade is achieved. In group 2, a
tracheal tube is preloaded over a GlideRite® stylet, which is specifically designed to work
with GlideScope® video laryngoscope (Verathon Medical, Bothell, WA, USA). GlideScope® blade
size 3 (GS-3) or 4 (GS-4) is used in all participants. In group 3, tracheal tubes are
prepared with a hockey stick-shaped stylet, and direct laryngoscopy is performed using a
size-3 or -4 Macintosh blade (Rüsch Inc., Duluth, GA, USA). In all participants, backward,
upward, and rightward pressure on the larynx and Sellick maneuvers are allowable to obtain
the best glottic view.55,56 If the initial intubation attempt fails or is terminated for
desaturation (defined as SpO2 < 92%) or need to change the patient's position, the intubation
device will be removed, and manual bag mask ventilation will be performed. Intubation failure
is defined as more than three intubation attempts or need to change intubation devices. Any
intubation rescue techniques will be used at the discretion of the staff anesthesiologist.
Primary outcome is the best glottis visualization, graded according to Cormack and Lehane's
classification with external laryngeal pressure applied.57 Glottic views graded as III or IV
are regarded as difficult.
Substudy 4: An investigation of the putative benefits of goal-directed hemodynamic therapy
targeting cardiac index in obese patients undergoing laparoscopic sleeve gastrectomy
At the operation room, the investigators will apply the Masimo Radical 7 pulse oximetry
(Masimo Corp., Irvine, CA, USA) to the fingers of all enrolled patients to measure perfusion
index and SpO2 throughout the surgery. After the placement of a tracheal tube, patients will
receive ventilator support with the tidal volume 6-8 ml·kg-1 ideal body weight, a respiratory
rate of 10-15 min-1 and PEEP 5 cmH2O applied by the ventilator.60 The FiO2 will be set at
0.3-0.7 to maintain SpO2 ≥ 98% throughout the surgery. Each patient will be randomly
allocated to one of each of the following two groups: goal-directed hemodynamic therapy and
control.
In both groups, intraoperative maintenance rate of crystalloid fluids is 3 ml·kg-1·hr-1 ideal
body weight. ProAQT®-derived hemodynamic data and peripheral perfusion index and SpO2 will be
acquired at the following time points: 5 min after induction of anesthesia, 5 min after start
of pneumoperitoneum and head-up tilting, 5 min after end of pneumoperitoneum, cessation of
volatile anesthetics, and 5 min after extubation. Subjects of the GDHT group will be managed
according to the ERAS algorithm utilizing ProAQT® parameters to maintain the cardiac index ≥
2.5 l·min-1·m-2.61 In brief, if cardiac index < 2.5 l·min-1·m-2, a bolus of 150 ml of
crystalloid fluid will be given until the stroke volume variation is < 10%. If cardiac index
< 2.5 l·min-1·m-2 despite the stroke volume variation of ≥ 10% following fluid challenge,
continuous intravenous infusion of dopamine 5-10 μg·kg-1·min-1 will be administered. If mean
arterial pressure is < 70 mmHg despite cardiac index ≥ 2.5 l·min-1·m-2, intravenous infusion
of norepinephrine 2-10 μg·min-1 will be used.
Subjects allocated to the control group are hemodynamically managed as per anesthesiologist
preference. Typically, isolated hypotension (20% decrease in mean arterial pressure below
baseline or < 60 mmHg) is treated by single or consecutive boluses of norepinephrine 5 or 10
μg. If hypotension persists, repeat boluses of ephedrine 4 mg will be administered until mean
arterial pressure is above 60 mmHg. If hypotension is accompanied by signs of hypovolemia
(urine output < 0.5 ml·kg-1·hr-1 and/or an increase in heart rate > 20% above baseline),
crystalloid or colloid fluids will be given until urine output and/or heart rate are
normalized. If hypotension persists despite volume challenge, norepinephrine will be used.
In both groups, the fluid, inotrope, and vasopressor responsiveness, ProAQT® parameters
(cardiac index, stroke volume variation, systemic vascular resistance, and mean arterial
pressure), and the signals of pulse oximetry (perfusion index and SpO2) will be evaluated and
recorded for each 15-min interval throughout the surgery. In control group, the ProAQT®
monitoring will be concealed from the anesthetist in charge. Artifact-free signals are
considered valid for statistical analysis. At the end of surgery, all participants will
receive a manual recruitment maneuver of 30 to 40 cmH2O for 10 s three times. In all
patients, cessation of volatile anesthetics will be timed to facilitate early awakening after
wound closure. All patients will be decurarized from rocuronium-induced neuromuscular
blockade with sugammadex dosed at 2 mg·kg-1 ideal body weight + 40%.62 Primary outcome is a
composite of major complications according to the European Perioperative Clinical Outcome
definitions within 30 days after surgery, including myocardial ischemia or infarction,
arrhythmia, acute kidney injury, gastrointestinal bleeding, anastomotic breakdown, surgical
site infection, and hospital-acquired pneumonia.63
