Effects of Sugammadex and Conventional Reversal on Lung Function in Laparoscopic Abdominal Surgery

Postoperative Pulmonary Complications (PPCs) are not uncommon. They increase healthcare resource usage as well as increase mortality of the patients. There are many definitions published in literature which can be considered as a composite outcome measure. This includes atelectasis, respiratory infection, respiratory failure, pleural effusion, pneumothorax, bronchospasm as well as aspiration pneumonitis (Jammer et al., 2015). After induction of general anaesthesia, the respiratory system changes occur immediately: muscle function and respiratory drive change, volume of lungs decreases, and atelectasis occurs in more than 75% of patients who were given neuromuscular blocking agent,

The problem and rationale of the study are described in the following paragraphs according to three postoperative conditions, 1) pulmonary function, 2) atelectasis, and 3) postoperative length of stay:

Postoperative pulmonary complications are one of the major problems after a surgery. Even if the surgery was successful, patient will still be facing morbidity or even mortality after the surgery. The risk of PPCs increases in patients having respiratory problem such as asthma, chronic obstructive pulmonary disease (COPD) and smoker . Many studies have shown the comparison between Sugammadex and conventionally used Neostigmine with respect to PPCs. However, studies regarding Sugammadex and Neostigmine in term of pulmonary function postoperative are still scarce as only two studies were found to comment directly on pulmonary function by using spirometry between neostigmine and sugammadex. In those studies, it shown that no significant different in term of spirometry volume postoperative between sugammadex and neostigmine . The authors believed postoperative analgesia plays important role in reported preservation of FVC.

Atelectasis as one of the commonest PPC can be worsen especially in laparoscopic surgery by the effect of Trendelenburg position and pneumoperitoneum. Residual paralysis even not in such condition (Trendelenburg, pneumoperitoneum) has been demonstrated to contribute to impaired upper airway and pulmonary function as well as respiratory adverse events in PACU and might make the atelectasis even worse. This shows that there is a need for an effective and complete reversal of neuromuscular blocker to prevent such event.

The length of stay after operation is important as it may present the quality of the health care system. However, there are many factors that can contribute to length of stay postoperative where postoperative pulmonary complications is one of the greatest contributors. A study which conducted by Ledowski et al. on elderly group more than 75 years old in centres across 5 countries (South Korea, Malaysia, Australia, Hungary, Netherlands) regarding comparison neostigmine and sugammadex showed that there is no significant different in length of stay. Only in Malaysia Ledowski et.al found that there is significant difference in terms of length of stay. Thus, further study is needed to compare the post operative length of stay between patients reversed with Sugammadex and Neostigmine.

From reviews of literatures, there is a gap in studies involving comparison of the effect of sugammadex and neostigmine as reversal. The gap lies in 1) the scarcity of studies involving Sugammadex and Neostigmine in terms of pulmonary function postoperative, 2) a need for an effective and complete reversal of neuromuscular blocker, and 3) further study on postoperative length of stay is needed.

Research Question(s)

1. Are there differences in the pulmonary function test preoperative and post extubation between Sugammadex and conventional reversal in laparoscopic abdominal surgery?
2. Are there differences in the size of atelectasis area between Sugammadex and conventional reversal in laparoscopic abdominal surgery?
3. Are there differences between sugammadex and conventional reversal in postoperative mean length of stay in laparoscopic abdominal surgery?

Thus, we formulate from the research questions with null hypothesis as below:

1. There is no difference in Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1), and FEV1/FVC preoperative and post extubation between Sugammadex and conventional reversal group in laparoscopic abdominal surgery
2. There is no difference in the size of atelectasis area using ultrasonography preoperative and post extubation between sugammadex and conventional reversal in laparoscopic abdominal surgery
3. There is no difference in mean postoperative length of stay (days) in hospital between sugammadex and conventional reversal in laparoscopic abdominal surgery Objective General: To compare the effect on lung function between sugammadex and conventional reversal in laparoscopic abdominal surgery

Specific:

1. To compare the Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1), and FEV1/FVC using portable spirometry preoperative and post extubation between sugammadex and conventional reversal in laparoscopic abdominal surgery
2. To identify and compare the size of atelectasis area using ultrasonography preoperative and post extubation between sugammadex and conventional reversal in laparoscopic abdominal surgery
3. To compare mean postoperative length of stay (days) in hospital between sugammadex and conventional reversal in laparoscopic abdominal surgery

All data collection will be collected at Hospital Universiti Sains Malaysia, Kubang Kerian. Patient will be identified based on inclusion and exclusion criteria from locations listed below:

1. Anaesthesia clinic
2. In the ward, during review by preanaesthesia review for the elective operation in the following day
3. In the ward, when cases are notified for operations as emergency case
4. In operation theatre, when cases notified arrived for emergency operation.

The informed consent will be obtained from patients either in ward, clinics or in Operation Theatre during emergency premedication at the airlock. The patient will be given ample time to decide on the participation. The consent for general anaesthesia also will be taken as part of standard practice. Related information such as fasting hours will be conveyed.

After consent is explained and taken, baseline spirometry and lung ultrasound (LUS) will be performed before general anaesthesia given, either in wards, clinics or operation theatre. This to get the baseline of pulmonary function as well as lung images. Spirometry will be performed following international recommendations but with patients in a semi recumbent position (40 degree) as recommended for postoperative position (Graham et al., 2019). FVC, FEV1 and forced expiratory flow 25-75% will be measured and recorded. Changes in lung aeration will be studied by LUS with the patient in the same position. LUS will be conducted on each lung in sagittal section at three predefined areas: parasternal, medial axillary line, and posterior axillary line (Lichtenstein, 2014). Brightness will be adjusted in setting to the brightest level in the bony surface of ribs. After that, the scale in cm2 will be set according to image resolutions in pixels. Presence of hepatization pattern of lung tissue will indicate the collapsed area. This suggesting atelectasis is present. The area will be measured in each area by taking the longest length vertically and horizontally, during end-expiration after freezing the image. The sum of all six area will be added, recorded and considered as size of atelectasis.

Patient will be induced by anaesthesiologist in-charge as routine clinical practice. Neuromuscular block will be performed using rocuronium prior intubation and monitored by train-of-four (TOF) Watch. Anaesthesiologist will be allowed to maintain TOF level according to usual criteria. Desflurane or sevoflurane will be used as maintenance.

After operation is completed, patient will be randomly assigned to receive either sugammadex 4mg/kg or neostigmine 40mcg/kg in combination with atropine 10mcg/kg using sealed opaque envelopes. The reversal will be given once the TOF ratio ranging between 0.7 to 0.9 as the diaphragm muscles and tidal volume are already back to normal (Wardhana et al., 2019). An extra dose of reversal is permitted by protocol, when needed, at the discretion of the attending anaesthesiologist. Patient will be extubated as usual local practice and will be sent to postoperative recovery room.

In order to ensure patient able to obey command, new spirometry will be performed in the postoperative recovery room only after 20 minutes of extubation with the same procedure and position used in the preoperative determinations. Postoperative clinical management will be conducted according to clinical preferences and local protocol. Additional lung ultrasound scan is performed as well at 20 minutes post extubation, just after spirometry. The spirometry is repeated at 60 minutes post extubation. All measurements will be recorded.

Another spirometry will be done 24H after operation in ward in the same manner and measurement will be recorded. The patient will be followed up in ward until discharge and the length of stay postoperative will be recorded.