ProSeal Laryngeal Mask Airway versus Cuffed Endotracheal Tube for Laparoscopic Surgical Procedures under General Anesthesia: A Random Comparative Study.

CONTEXT: The Proseal LMA(PLMA), which has been designed especially for positive pressure ventilation and protection against aspiration can act as an alternative to Endotracheal Tube (ETT) as an effective airway device for patients undergoing elective Laparoscopic surgeries. AIMS: To compare the efficacy and safety of PLMA with ETT in patients undergoing Laparoscopic surgeries under general anaesthesia. SETTINGS AND
DESIGN: A prospective, randomized study was conducted in a tertiary care teaching hospital with 60 patients of ASA grade I/II undergoing elective Laparoscopic surgery under general anaesthesia. Ethical committee clearance and written consent taken. The patients were randomly divided into two equal groups to the PLMA group (Group S) and to the ETT group (Group C) Heart rate (HR), mean blood pressure (MAP), ETCO2 values, intraoperative complications such as regurgitation- aspiration, and Postoperative complications such as nausea or vomiting, throat soreness and oral injuries were monitored.
RESULTS: There was no difference demographically. Insertion success rate was 100% for both the groups. The mean increase in HR was seen all throughout the duration of the surgery to 8 % above the baseline in Group C and to 3% above the baseline in Group S. On comparing the MAP in Group C, there was a increased by 2.5% to 78.300 ± 14.2615 mmHg as compared to an increase by 5% to 76.233 ± 6.2072 mmHg in Group S. EtCO2 showed a rise in both groups after pneumoperitoneum, which returned to baseline values after completion of surgery. Gastric aspirate values showed no difference in each group. Post op complications were seen mainly in Group C with statistical significance.
CONCLUSIONS: A properly positioned PLMA is a suitable and safe alternative to ETT for airway management in adequately fasted, adult patients undergoing elective Laparoscopic surgeries.

INTRODUCTION

The development of minimally invasive surgery has revolutionized surgical procedures and has influenced the practice of anesthesiology. The success in healthy adult patients has led to the introduction of more extensive endoscopic procedures in older and sicker patients, as well as in pregnant and pediatric patients. Despite the potential advantages, Laparoscopic procedures are associated with physiological hemodynamic changes and life-threatening complications such as regurgitation of the gastric contents and potential aspiration due to physiological changes associated with pneumoperitoneum that are usually not encountered with the conventional open procedure. As a result, anesthetic techniques for Laparoscopic surgery have been refined to anticipate these differences from open surgery.[1]

Maintenance of a patent airway remains an important concern of an anesthesiologist.[2] Even though the time tested and excellent airway securing device, i.e., the Endotracheal Tube (ETT), is available at all times, it too has its demerits. Morbidities such as trauma to the vocal cords and structures of the oral cavity, pressor response, and sore throat are worrisome to the anesthesiologist. This led to the use of supraglottic devices such as ProSeal laryngeal mask airway (PLMA) for Laparoscopic surgeries.[3]

PLMA is a double-lumen, double-cuff LMA. The double-tube design separated the respiratory and the alimentary tracks providing a separate passage for the regurgitated fluids. Furthermore, the double cuff provided a better seal around the glottis, thus providing an option of administering intermittent positive-pressure ventilation[45] These properties increase the suitability to use PLMA in patients who are more prone to aspiration of regurgitated fluids.

The aim of our study is to compare the efficacy and safety of PLMA with ETT in patients undergoing Laparoscopic surgeries under general anesthesia.

SUBJECTS AND METHODS

Patient selection

After obtaining approval from Ethical Committee, sixty patients were chosen who were scheduled to undergo elective Laparoscopic surgeries under general anesthesia. The duration of this study was 1 year. Written informed consents were obtained from the patients. The inclusion criteria were patients with American Society of Anesthesiologists (ASA) Physical Status I and II, aged 18–60 years. Patients were excluded if they had a mouth opening <2 cm, anticipated difficult airway, ASA Physical Status III or IV, body mass index >30 kgm−2, upper respiratory tract infection, increased risk of aspiration (gastroesophageal reflux disorder, hiatus hernia, and pregnancy), cervical spine fracture, or instability. The patients were randomly divided into two groups (according to a computer generated plan) – thirty patients to the ProSeal group (Group S) and thirty patients to the ETT group (Group C).

Study procedure

A thorough preanesthetic checkup was performed 1 day before the day of the surgery. All patients were given tablet alprazolam 0.5 mg orally at bedtime on the previous night of surgery and kept nil per oral for 12 h before surgery. After the patient was shifted to operation theater, standard monitors such as pulse oximeter, noninvasive blood pressure, and three-lead electrocardiogram were connected. Intravenous (IV) access was gained with 18-gauge cannula and Ringer's lactate infusion was started. The patients were given injection glycopyrrolate 0.2 mg IV, injection midazolam 0.05 mg/kg IV, injection fentanyl 1 μg/kg IV, injection ondansetron 4 mg IV, and injection pantoprazole 40 mg IV and then preoxygenated with 100% oxygen for 3 min. Anesthesia was induced with injection propofol 2.5 mg/kg IV, and injection atracurium 0.75 mg/kg IV was used to achieve neuromuscular blockade. The patients were ventilated for 3 min with oxygen and isoflurane 0.8%, and the device was inserted by trained anesthesia providers with significant experience and expertise in insertion.

Group S (study group): PLMA (size 3 for females, size 4 for males) with introducer

Group C (control group): cuffed ETT (size 7–7.5 ID for females, size 8–8.5 ID for males).

Correct placement of the device was confirmed by manual ventilation, auscultation, and square wave capnography. Once confirmed, positive-pressure ventilation was started with a tidal volume of 8 ml/kg. Closed circuit breathing system with soda lime was used. Maximum three attempts were allowed while inserting the airway device. If more than three attempts were required for device insertion, the patient was excluded from the study as repeated laryngoscopic response may alter the hemodynamic parameters under study.

Ease of insertion of the device was noted.

Ryle's tube was inserted. Correct placement of the Ryle's tube was checked with air injection and epigastric auscultation. Volume of gastric aspiration was measured just after insertion of Ryle's tube and intraoperatively.

Anesthesia was maintained by isoflurane 0.5%–1.2%, air: O2 (60%: 40%) connected to Drager Fabius machine and put on volume mode along with injection atracurium 0.25–0.4 mg/kg for the maintenance of blockade. IV crystalloids were administered after calculating fluid requirements according to Holliday-Segar formula. CO2 pressures and flow rates were monitored and ranged between 10 and 15 mmHg and 200 and 400 ml/min, respectively, in all cases.

Heart rate (HR) and mean blood pressure were recorded before induction, at 1 and 5 min after the insertion of the device, during CO2 insufflation, every 15 min interval throughout surgery, and then 5 min after removal of airway device.

ETCO2 values were monitored similarly.

Intraoperative complications such as regurgitation-aspiration, hypoxia, hypercarbia, bronchospasm, airway obstruction, gastric insufflation, and pneumothorax were looked for.

At the completion of surgery, isoflurane was stopped. Residual paralysis was reversed with injection neostigmine 0.05 mg/kg and injection glycopyrrolate 0.008 mg/kg. Postoperative analgesia was administered with IV injection diclofenac sodium 75 mg as infusion.

The device was removed after thorough Ryle's tube and oral suction. Any blood or secretions present on the device were noted.

Postoperatively, patients were monitored for vital parameters, nausea or vomiting, throat soreness, and oral injuries.

OBSERVATION AND RESULTS

In this prospective randomized study, sixty patients aged 18–60 years of ASA Physical Status I and II undergoing elective Laparoscopic surgery were studied to evaluate hemodynamic response and postoperative complications after securing the airway with either the ETT or the PLMA.

The sample size was determined by power analysis. Patients listed for surgery were enrolled and assessed for eligibility. Those not meeting the inclusion criteria or those refusing to participate were excluded from the study.

The data collection sheets were checked daily by the principal investigator for correctness and consistency. Data collected were coded and entered into the SPSS software. Data were analyzed using SPSS version 22.0 (SPSS Statistics for Windows, Armonk, NY: IBM Corp); analysis between the groups was done using the unpaired sample t-test while within-group analysis was done using the paired sample t-test. Chi-square test was used for qualitative data.

Continuous variables were described using mean ± standard deviation. A P value of <0.05 was considered statistically significant.

Demographic profile

There were no statistical differences (P > 0.05) between the groups regarding age, gender, weight, and height. All the data were statistically insignificant and thus comparable. Table 1 shows the comparison of demographic parameters of all patients.

Table 1

Comparison of demographic parameters

Insertion of device

Table 2 describes the insertion of device. Insertion success rate was 100% for both the groups.

Table 2

Insertion of device

Comparison of pulse variation

Comparison of pulse variation is presented in Table 3. Preoperatively, baseline mean pulse rate in Group S was 78.6 ± 6.27 per min and that in Group C was 79.76 ± 6.65, with P = 0.23; thus, there was no statistical significance in both the groups.

Table 3

Comparison of pulse variation

During induction, there was a rise in mean pulse rate in Group S to 81.80 ± 5.851 per min and in Group C to 82 ± 5.343 per min; however, the statistical analysis showed no significance.

After insertion of the device, in Group S, mean pulse rate increased by 8% to 84.79 ± 7.497 per min, whereas in Group C, the mean pulse rate increased by 10% to 87.5 ± 6.725 per min. Even though there was a greater rise in mean pulse rate in Group C as compared to Group S, there was no statistical significance seen as per P value.

As shown in Table 3, the mean increase in the pulse rate was seen all throughout the duration of the surgery and pneumoperitoneum to 8% above the baseline in Group C as compared to 3% above the baseline in Group S. However, there was no statistical significance seen as per the P values.

The mean pulse rate thus showed better hemodynamic stability in Group S as compared to Group C.

Comparison of mean arterial blood pressure variation

Comparison of mean arterial blood pressure variation is presented in Table 4

Table 4

Comparison of mean arterial blood pressure variation

Preoperatively, baseline mean arterial pressure (MAP) in Group S was 74.133 ± 5.7938 mmHg and that in Group C was 75.233 ± 6.0554 mmHg, with P = 0.475; thus, there was no statistical significance in both the groups.

During induction, there was no significant change in mean MAP in both the groups.

After insertion of the device, in Group S, there was an increase in mean MAP by 5% to 76.233 ± 6.2072 mmHg, whereas in Group C, the mean MAP increased by 2.5% to 78.300 ± 14.2615 mmHg. Even though there was a greater rise in mean MAP in Group C as compared to Group S, there was no statistical significance seen as per the P value. The values of MAP gradually returned to the baseline values, with no statistical significance seen as per the P values. The mean MAP thus showed better hemodynamic stability in Group S as compared to Group C.

Comparison of end-tidal carbon dioxide variation

Table 5 shows the comparison of end-tidal carbon dioxide variation. On comparison, no statistical significance was noted in both the groups.

Table 5

Comparison of end-tidal carbon dioxide variation

Comparison of gastric aspirate

Graph 1 shows the comparison of gastric aspirate variations. On statistical analysis of the data with Chi-square test, there was no statistical difference seen (P = 0.34) Thus, there was no difference in the amount of gastric fluid aspirated in each group.

Graph 1

Comparison of gastric aspirate variations

Regurgitation of the gastric contents through the drain tube was not seen in any of the patients. There was no case of pulmonary aspiration.

There was no case of intraoperative displacement of the device.

Postoperative complications

Comparison of postoperative complications is presented in Table 6. As shown in Table 6, postoperative complications such as nausea, sore throat, and airway trauma were seen mainly in patients with ETT (Group C) with statistical significance (P = 0.038, 0.002, 0.001, respectively); vomiting was not seen in any group postoperatively.

Table 6

Comparison of postoperative complications

DISCUSSION

This study was carried out to compare the PLMA and the ETT as an airway device during general anesthesia during elective Laparoscopic surgeries in sixty ASA Grade I and II patients who were randomly allotted into one of the two groups containing thirty participants each, with respect to their intraoperative hemodynamic parameters and postoperative complications.

Both groups were given similar standardized anesthesia and were compared for similar parameters including demographic details, ease of insertion, volume of gastric aspirate, hemodynamic alterations, and postoperative complications.

The two groups were comparable in terms of demographic data.

We compared the ease of insertion, attempts for insertion, and the success rate of insertion in both groups and observed that the insertion success rate was 100% in both.

Our findings correlate well with Lim et al.,[6] who found that the number of attempts for successful insertion was similar between the both the groups and that both the devices were successfully inserted within three attempts.

Oehler has compared different techniques of PLMA insertion.[7] Their observation in terms of first-time success rate at insertion of PLMA by introducer technique and the number of attempts for successful airway attainment coincide with our study.

On comparing the hemodynamic parameters, both the groups were comparable in terms of baseline hemodynamic parameters.

Our study demonstrated that there was a hemodynamic response consisting of an increase in HR and MAP associated with laryngoscopy and ETT insertion as well as with PLMA insertion. The response caused by laryngoscopy with ETT insertion was greater than that caused by PLMA insertion. However, no statistical significance was noted. Similar results were seen by Güleç et al.,[8] who concluded that PLMA usage is a suitable, effective, and safe alternative to ETT in patients with lower metabolic stress.

The hemodynamic parameters were elevated to 10%–15% above the baseline values after the insertion in patients of the ETT group and gradually settled to 5%–8% above the baseline for the remaining duration of the surgery. These results are comparable to those found by Kanchi et al.[9] and Takahashi et al.,[10] who found that in normotensive patients, laryngoscopy and endotracheal intubation are immediately followed by an increase in the sympathetic response and hemodynamic parameters.

The PLMA group in our study showed a 6%–8% increase in hemodynamic parameters after insertion, which was lower than that seen in patients with ETT. These parameters gradually settled to 1%–3% above the baseline for the remaining duration of the surgery.

These findings are supported by Misra and Ramamurthy[11] and Lim et al.,[6] who concluded that the PLMA is a similarly effective airway device to conventional laryngoscope-guided tracheal intubation but is more rapidly inserted and associated with an attenuated hemodynamic response to insertion and removal.

Idrees and Khan[12] noted that the hemodynamic response to insertion was significantly attenuated in LMA group as compared to ETT group. They concluded that this attenuated hemodynamic response to insertion of LMA as compared to ETT will be beneficial in patients with compromised cardiovascular profile, and hence, it has a safer hemodynamic profile compared to ETT.

Laparoscopic surgery cause changes in respiratory mechanics following carbon dioxide pneumoperitoneum. The pulmonary compliance is decreased and the resistance is increased leading to high airway pressure. Therefore, higher inspiratory pressures are required to provide adequate tidal volume and minute ventilation to maintain adequate airway pressures and end-tidal carbon dioxide levels.[1314]

On comparing the mean end-tidal carbon dioxide levels in both the groups, the values of ETCO2 were comparable in both the groups on insertion of the airway device; however, there was a rise in both groups after laparoscopy and pneumoperitoneum, which returned to baseline values after completion of surgery. This variation was comparable all throughout the duration of surgery with no statistically significant difference.

Ryle's tube was inserted successfully in all our patients in the first attempt along with the insertion of either device. In comparison, Cook et al.[15] were successful in 92%. Sharma et al.[16] had a success rate of gastric tube placement of 100%.

On comparing the mean values of gastric aspirate in both groups, we noted minimal mean gastric aspirate in both the groups with no statistical significance. This could be attributed to elective nature of the surgery where appropriate aspiration prophylaxis was administered. Regurgitation of the gastric contents through the drain tube was not seen in any of the patients.

Cook et al.[17] observed that the drain tube enables early diagnosis of mask misplacement, allows gastric drainage, reduces gastric inflation, and may vent regurgitated stomach contents and also that the correctly placed PLMA reduces aspiration risk Evans et al.[18] described a case of intraoperative passive regurgitation where the PLMA successfully protected the airway from the respiratory tract illustrates that passive regurgitation can occur unexpectedly intraoperatively and thus the PLMA can protect the airway during such an event by allowing the regurgitated fluid to pass up the drainage tube without leaking into the glottis.

We compared postoperative complications such as nausea, vomiting, airway trauma, and sore throat in both the groups. 16.67% patients in ETT group experienced nausea 6.67% patients in PLMA group. These values were statistically significant. 13.33% patients in the ETT group had sore throat postoperatively. No patient in the PLMA group experienced this complication, which was statistically significant.

Airway trauma was seen in 1.67% of all the cases. This was highly statistically significant.

Higgins et al.[19] showed that patients with ETT had the greatest incidence of sore throat; 45.4%, followed by patients with LMA.

Saraswat et al.[20] found that sore throat postoperatively was seen in 10% patients with PLMA and in 20% patients with ETT and noted airway trauma in 10% patients with PLMA and in 16.67% patients with ETT.

No incidence of vomiting postoperatively in any groups. This could be attributed to appropriate antacid prophylaxis and Ryle's tube suctioning, before extubation.

SUMMARY AND CONCLUSION

We summarize that in the patients undergoing elective Laparoscopic surgeries:

The PLMA has similar ease of insertion as the ETT

PLMA has better hemodynamic stability

PLMA is an equally good conduit for delivery of positive pressure ventilation and provides an effective airway seal with minimal chances gastric distension and but no regurgitation or aspiration in patients undergoing general anesthesia during Laparoscopic surgeries

PLMA reduces the chances of postoperative complications such as nausea, sore throat, and vomiting and airway trauma and hence is desirable especially for day care procedures.

Hence, we conclude that a properly positioned PLMA is a suitable and safe alternative to ETT for airway management in adequately fasted, adult patients undergoing elective Laparoscopic surgeries. It provides equally effective pulmonary ventilation without gastric distention, regurgitation, and aspiration.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.