Effect of depth of neuromuscular block on intraoperative surgical conditions as determined by the Leiden Surgical Rating Scale in morbidly obese patients undergoing laparoscopic bariatric surgery

In laparoscopic surgery, especially when surgery is performed in morbidly obese
patients, surgical conditions are determined in a major if not exclusive part
by the depth of the neuromuscular block. A deep block (PTC 1-2) is often
associated with improved surgical conditions and is therefore requested by the
surgeons. However, a deep block comes at the expense of a variety of items that
may conflict with its use including long recovery times, postoperative
ventilation and impaired postoperative breathing conditions with atelectasis
and hypoxia. With the introduction of Sugammadex there is now the possibility
to reverse an even deep surgical block. This may overcome most of the issues
mentioned.

Previously we showed that a deep NMB coincided with favorable surgical
conditions in lean patients undergoing elective laparoscopic retroperitoneal
surgery for prostatectomy or nephrectomy (See Figure 1). During a moderate NMB
20% of surgical scorings were less than good, during deep NMB 99% of scorings
were excellent. In the current study we will examine the effect of the depth of
the neuromuscular block in morbidly obese patients on one major end-point:


To address these research questions, we will relax morbidly obese patients
undergoing bariatric surgery with rocuronium. Patients will be randomly
assigned to receive a moderate neuromuscular block (standard care) with a TOF
of 1-2 or a deep NMB (deep block) with a TOF of zero and PTC of 1-2. Rocuronium
will be administered as bolus infusion ranging from 0.6 - 1 mg/kg. Titration
to effect will be performed immediately after intubation.

After surgery had ended patients that received standard care will be reversed
with 2 mg/kg sugammadex, while patient that received the deep block will
receive 4 mg/kg sugammadex. Extubation will be performed when the TOF ratio >
0.9 and the patients breathes adequately.

In the post-anesthesia care unit the cardiorespiratory parameters (blood
pressure, heart rate oxygen saturation), the level of pain (on an 11-point
numerical rating scale), sedation and the PRQS will be measured at 15 min
intervals until discharge to the ward.

The results of the study will give the following valuable information:
1. Does the level of muscle relaxation affect surgical conditions when
performing laparoscopic bariatric surgery?
2. Does a deep block lead to improved hemodynamic conditions during surgery?
3. What is the respiratory condition of the patients following a deep block?
4. Do patients after laparoscopic bariatric surgery experience less pain
compared to patients with a moderate neuromuscular block?
5. Does reversal with sugammadex lead to similar quality of recovery despite
dissimilar depths of neuromuscular block?
Finally, the current study will add to the existing database on the association
between the depth of the neuromuscular block and the rating of surgical
conditions. A meta-analysis will be performed on the current data set (BLISS
1-3) allowing confirmation of the association between a deep block and improved
surgical conditions in over 160 patients undergoing complex laparoscopic
surgery.

- To assess whether the implementation of a deep neuromuscular block (NMB) (PTC
1-2) combined creates optimal surgical conditions as measured by the surgeon
(using the 5-point Leiden surgical rating scale) versus a moderate
neuromuscular block (TOF 1-2) in morbidly obese patients undergoing bariatric
surgery.
-To assess whether reversal of the deep NMB with sugammadex 4 mg/kg results in
optimal cardiorespiratory conditions in the post-anesthesia care unit.

Hypotheses
-Deep NMB combined will result in a significant improvement of surgical
conditions compared to moderate NMB;
-Reversal of deep NMB with sugammadex results in optimal cardiorespiratory
conditions in the postanesthesia care unit.

This is a randomized control trial (RCT) performed

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