Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT06058481 |
| Other study ID # |
FF-2019-365 |
| Secondary ID |
Fundamental data |
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
July 31, 2019 |
| Est. completion date |
July 31, 2020 |
Study information
| Verified date |
September 2023 |
| Source |
Universiti Kebangsaan Malaysia Medical Centre |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Patients aged 19 to 78 years with ASA status I-II scheduled for elective surgery under
general anesthesia, were recruited and randomized into two groups, Group A (BlockBuster) and
Group B (Proseal-LMA). Anesthesia induction for both groups was standardized with no
paralysis given. Supraglottic airway (SGA) insertion (either Blockbuster or Proseal-LMA) was
executed by a single experienced investigator. The investigator inserted the BlockBuster in
Group A patients and the Proseal-LMA in Group B patients. These parameters were compared
between the groups; the number of attempts, time taken to achieve successful insertion,
oropharyngeal leak pressure (OLP), fiberoptic view of SGA position, hemodynamics changes and
complications from the insertion.
Description:
This prospective, randomised single-blinded study, was conducted at the operation theatre of
Universiti Kebangsaan Malaysia Medical Centre (UKMMC), following approval from the
Institutional Ethics Committee of Universiti Kebangsaan Malaysia (UKM). The recruited
patients were within the age range of 19 to 78 years, classified as American Society of
Anesthesiologists Physical Status (ASA) class I or II, and underwent elective surgery under
general anesthesia that required supraglottic airway (SGA) insertion. Exclusion criteria
included a body mass index (BMI) over 35 kg/m2, limited mouth opening of less than two finger
breath of inter-dental gap, edentulous, loose teeth, airway abnormalities, risk of
aspiration, and known allergies to fentanyl and propofol.
During the pre-operative visit, patients were briefed about the study, and written informed
consent was obtained. All recruited patients were fasted for at least 6 hours before the
scheduled operation. No premedication was administered. Patients were then randomly assigned
to either Group A (Blockbuster) or Group B (Proseal-LMA) using simple randomisation. SGA
insertion was performed by a single operator with more than five years of experience using
the Proseal-LMA and had received training using Blockbuster on a mannequin and successfully
inserted it in 20 patients .
In the operation theatre, minimal standard monitoring was applied and followed by
preoxygenation for three minutes. Anesthesia induction was conducted using intravenous (IV)
fentanyl of 2 mcg/kg and IV propofol of 2 to 2.5 mg/kg. Additional propofol boluses of 10 to
20 mg were administered if anesthesia was inadequate and the doses were documented.
Neuromuscular relaxant was not used. After achieving unconsciousness, mask ventilation was
initiated with an oxygen and sevoflurane mixture until a Minimum Alveolar Concentration (MAC)
of 1.3 was achieved. The depth of anesthesia was assessed by pupillary size and jaw
relaxation prior to SGA insertion. The appropriate size of the SGA was chosen based on the
manufacturer's recommendation according to the patient's body weight. Before SGA insertion,
lubrication was applied to the outer cuff with a water-based lubricant and the cuff was fully
deflated.
An assigned assistant recorded the number of attempts and time taken for successful
insertion. The time taken for SGA insertion was measured from the moment SGA passes the
patient's front incisor until the appearance of the first end-tidal CO2 (ETCO2) waveform on
the capnography. The measurement of time was stopped and reset for subsequent attempts. The
investigator inserted the BlockBuster in Group A patients and the Proseal-LMA in Group B
patients. The Proseal-LMA is a reusable device and the items that used in this study was used
less than 10 times previously. After SGA insertion, the cuff was inflated to a pressure of 60
cmH2O using a cuff pressure manometer. Successful insertion was determined by these three
findings: chest expansion, no audible leak detected during manual bagging and the appearance
of square wave capnograph tracing with ventilation generating expiratory tidal volumes of 6
to 8 ml/kg with an oxygen flow of 6 litre/min, adjustable pressure-limiting (APL) valve
closed at 30 cmH2O. An audible leak was determined by listening at the mouth or lateral
thyroid cartilage using a stethoscope for audible noise.
Following successful SGA insertion, a gastric tube sized 12 or 14 Fr was inserted.
Oropharyngeal leak pressure (OLP) was assessed by setting the APL valve of the circle system
at 30 cmH2O with a fresh gas flow of 3L/min. The OLP was determined by observing the airway
pressure at equilibrium until an audible noise was heard over the mouth with a stethoscope.
For safety reasons, the OLP was kept below 40 cmH2O and pressure was recorded.
The removal of SGA from the oral cavity was considered a failed attempt. If there was a
failure of insertion or failure of placement of SGA (inadequate chest expansion, inability to
generate adequate tidal volume or audible leak), the patient was ventilated again with 100%
oxygen and 3% sevoflurane to maintain SpO2 above 95% before the next attempt. If
inappropriate SGA size due to a large leak (small size) or difficult insertion (large size),
new SGA insertion with different sizes was allowed once in this study. A maximum of three
attempts was allowed, after which the patient was considered as failed SGA insertion. The
subsequent airway management was determined by the responsible anaesthesiologist. The patient
was dropped out of this study and excluded from the analysis if failed SGA insertion after
three attempts and surgery duration exceeding two hours.
Anesthesia was maintained with sevoflurane in an air-oxygen mixture and ventilation was
adjusted to achieve an adequate tidal volume of 6 to 8 ml/kg. Blood pressure, mean arterial
pressure (MAP), heart rate (HR), ETCO2 and saturation were recorded at pre-induction, during
induction, as well as at 5 and 10 minutes after SGA insertion. The position of SGA after
insertion in relation to the laryngeal inlet was verified using an intubating bronchoscope
Ambu aScope 4 Broncho Regular Endoscope (Ambu A/S, Denmark) with a working channel width of
2.2mm. The laryngeal view obtained was scored according to Keller et al. grading system:
Grade 4, only vocal cords visible; Grade 3, vocal cords plus posterior epiglottis visible;
Grade 2, vocal cords plus anterior epiglottis visible; Grade 1, vocal cords not visible.
The presence of airway complications related to SGA insertion such as laryngospasm,
bronchospasm, gagging, coughing and aspiration was recorded and managed by the responsible
anaesthesiologist. At the end of the operation, sevoflurane was discontinued, and the patient
was allowed to breathe spontaneously in 100% oxygen. The SGA was removed once the patient had
regained consciousness, was responsive to verbal commands and was able to breathe
spontaneously generating tidal volumes of at least 6 to 8 ml/kg. Following SGA removal, the
device was checked for blood-stained secretion and documented. The duration of anesthesia was
recorded and was defined as the time taken from anesthesia induction until SGA removal.
Patients were evaluated for the incidence of sore throat in the recovery area and at 24 hours
post-anesthesia.
