Ultra Sound Guided Rectus Sheath Block or Field Block for Midline Hernia Repair: A Comparative Study
Phase: NA
Conditions: Ultrasound Guided Rectus Sheath Block, Pain, Postoperative
Sponsor: Theodor Bilharz Research Institute

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Comparison Between Ultra Sound Guided Rectus Sheath Block and Field Block for Midline Hernia Repair 
NCT03225313 
Start Date 20th August 2017 
 
 
 
Investigators: 
 
1. Mohammed Sayed Faried Awad Hassan 
 
 
 
 
a.   Other Investigators 
 
Prof. Dr. Mounis A.M. Abo Sedira. 
 
Dr. Mohammed Hussein 
Prof. Dr. Iris Nessim 
Prof. Dr. Neamat Ahmed Ibrahim 
Prof. Dr. Eman Ahmed  Fouad 
c.  Department name 
Anesthesia Department. 
 
 
 
Background and Rationale : 
 
Pain is a complex but an important protective phenomenon. It may be defined as an 
unpleasant sensory and emotional experience associated with actual or potential tissue 
damage or described in terms of such damage (1). Good operative analgesia reduces 
the stress response to surgery, which is very important for patients with compromised 
cardiovascular respiratory functions (1). Good postoperative pain relief is important as 
it alleviates patient's distress and helps in rapid uncomplicated recovery (1).  
 
Field block achieved by wound infiltration is a method of postoperative analgesia 
commonly used alone or as a part of multimodal analgesic regimens (2). It was 
developed to improve postoperative analgesia, reduce opioid consumption  and  

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hasten  patient     recovery  .The use of local anesthetics (LAs) instead of opioid 
minimizes opioid adverse reactions, reduces nursing work, decreases resting pain, 
pain on motion, and thus allows better patient mobility (2). Field block carries the risk 
of wound infection and some surgeons oppose its use. 
A rectus sheath block can provide effective pain relief for umbilical or other midline 
surgical incisions by blocking the intercostals nerves. It can be done using the 
landmark technique but it carries the risk of puncturing the posterior rectus sheath, 
peritoneum and bowel (3).  
Use of ultrasound technology for rectus sheath block has reduced this risk 
considerably (3).Ultrasound guidance for regional anesthesia is associated with higher 
block success rates, shorter onset times, and reduced total anesthetic dose required 
and reduced complications. There is also the advantage of direct observation of 
pattern of anesthetic spread (4).  
 
Objectives : 
 
To compare between Ultra-sound guided rectus sheath block VS Field block 
infiltration in providing a good analgesia for patients undergoing midline hernia repair 
to detect which one is superior. 
 
 
Study Design  : 
 
Prospective randomized double blinded controlled clinical trial will be done with a 
total number of 75 patients will be divided into 3 groups . 
 
 
 
Ethics Committee approval   ( was it ethically approved by the department) : 
 
This protocol has been approved by the Ethics Committee at Theodor Bilharz 
Research Institute . 

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Study Methods : 
Population of study & disease condition: 
 
➢ 75 patients( ASA I or II ) undergoing midline hernia repair under general 
anesthesia  will be recruited and will be randomly allocated using a computer 
generated 
randomization 
table 
(research 
randomizer, 
https://www.randomizer.org). The allocation was kept in brown sealed envelopes.  
➢ Control group. 
➢ Field block infilteration group. 
➢ Ultra sound Guided Rectus sheath block group. 
Inclusion criteria: 
 
1. Elective midline hernia repair surgery. 
2. Age: adult patients between 18 – 60 years old. 
3. Gender: Both male and female. 
4. ASA Class: I & II. 
Exclusion criteria: 
 
1. Refusal of patient. 
2. Pregnancy and lactation. 
3. Fever or sepsis. 
4. Patients  ASA III or IV. 
5. Renal impairment. 
6. Addicts and drug abusers. 

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7. Patients taking corticosteroids or any cardio - active drugs. 
8. Local infection at site of the injection. 
9. Allergy to any of the study medications. 
 
 
Methodology in details : 
 
Anesthesia technique: 
 
✓ Preoperative : 
 
• During the pre-operative period visual analog scale (VAS) for pain assessment 
from 0 to 10, with 0 meaning no pain and 10 meaning the worst pain 
imaginable will be explained to patients. 
• 30 minute before surgery, IV 20 G cannula will be inserted in each patient 
forearm to collect 5 ml venous blood as preoperative sample for estimation of 
the level of cortisol and catecholamine. 
 
✓ Monitoring : 
In theatre, a five-lead ECG, non-invasive blood pressure, pulse oximetry, end-
tidal carbon dioxide and neuromuscular monitoring (Infinity Kappa, Dräger, 
Lübeck, Germany). Bi-spectral (BIS) module (InfinityⓇ BISxTM SmartPodⓇ, 
smoothing rate: 15 or 30 seconds, software revision: VF5) was attached to the 
patients' forehead for the depth of anaesthesia monitoring using disposable BIS 
electrodes (BIS Quatro, Aspect Medical Systems, USA) after proper skin 
preparation, 
were 
attached 
to 
the 
patient 
 
✓ Induction and maintenance 

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• During mask preoxygenation, patients baseline hemodynamic parameters will 
be recorded  regarding blood pressure, heart rate . 
• General  anesthesia will be standardized for all patients with :  
2 µg kg-1 fentanyl and 2 mg kg-1 propofol. Neuromuscular blockade will be 
achieved with 0.5 mg kg-1 atracurium followed by tracheal intubation. 
Muscle relaxation will be maintained by 0.1mg / kg / 30 minute of Atracrurium. 
• Mechanical ventilation will be adjusted with fresh gas flow oxygen in air 30-
50% at a rate of 1 L min-1to maintain end-tidal carbon dioxide of 35-40 mm Hg 
and  Spo2 greater than 94%.  
• BIS values will be maintained between 40 and 60. 
• All surgical procedures will be done in the range between 10 am and 1 pm and 
by the same surgical team. 
• Patients hemodynamic parameters regarding blood pressure and heart rate  will 
be recorded every 2.5 minutes. 
• Core temperature will be measured using an esophageal thermometer and 
normothermia will be maintained using a forced air warming blanket and 
actively warmed infused solution. 
• Patients will receive ringer solution infusion at a rate 2 - 5 ml / kg / hour. 
• Patients were randomly allocated to one of three groups namely the control 
group (Group C), the field block group (Group FB), or the RSB group (Group 
RSB) according to a computer generated randomization table (research 
randomizer, https://www.randomizer.org). Patients in the Field block group 
received a sham bilateral RSB using a total volume of 0.3ml. kg-1 of normal 

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saline plus a field block using 0.3ml. kg-1 of 0.5% bupivacaine. The RSB group 
received a bilateral RSB using a total volume of 0.3ml. kg-1 of 0.5 % 
bupivacaine plus a sham field block using 0.3 ml. kg-1 of normal  saline. The 
control group received 0.3 ml. kg-1 of normal saline for each block. A colleague 
not participating in the trial prepared the syringes that were used for the blocks.  
The patients, the anaesthetist administering the blocks, and colleagues 
collecting the postoperative observations were not aware of group allocation or 
injectate composition.  
• An increase in HR and/or MAP > 25 % of baseline values will be treated by IV 
fentanyl 0.5 μg kg-1 boluses & the total fentanyl dose will be recorded.  
Atropine 0.5 mg increments will be used to control bradycardia (<50 beat min-
1) while hypotension (less than 20% of preanesthetic level) will be managed by 
increasing 
fluid 
infusion 
rate 
or 
decreasing 
inhalational 
anesthetic 
concentration. 
• Reversal of neuromuscular blockade will be achieved by intravenous 
administration of neostigmine 0.05 mg kg-1 and atropine 0.02 mg kg-1. 
• Patients will be extubated and transferred to post- anesthetic care unit. 
• Postoperatively, pain was controlled using morphine PCA, paracetamol 1 gm 
intravenously every 6 hours and Diclofenac intravenously every 12 hours.  
• VAS will be recorded immediately post-operative, after 2, 4 and 6 hours. 
• Time to first analgesia requirement will be recorded and 24 hour postoperative 
morphine consumption will be recorded. 
• Nausea and vomiting will be recorded immediately postoperative using a 
categorical scoring system (0 = none, 1 = nausea, 2 = retching, 3 = vomiting). 
Ondansteron 4 – 8 mg i.v will be given for patients with score 2. 

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• Patients will be discharged out after scoring 12 points or more according to Fast 
track discharge  score (5) as follows : 
➢ Level of consciousness                      Score 
               Awake and oriented                                2 
Arousal with minimal stimulation      1 
Responsive only to tactile stimulation    0 
➢ Physical activity 
Able to move all extremities on 
command                                                 2 
Some weakness in movement of 
extremities                                               1 
               Unable to voluntarily move extremities  0 
 
➢ Hemodynamic stability 
Blood pressure  less than 15% of baseline  
MAP value                                                  2 
Blood pressure 15%–30% of baseline 
MAP value                                                  1 
Blood pressure  more than 30% below 
 baseline  MAP value                                 0 
 
➢ Respiratory stability 
Able to breathe deeply                                 2 
Tachypnea with good cough                        1 
Dyspneic with weak cough                          0 
 
➢ Oxygen saturation status 
Maintains value more than 90% on  

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room air                                                         2 
Requires supplemental oxygen (nasal 
prongs)                                                           1 
Saturation  less than 90% with  
supplemental oxygen                                     0 
 
➢ Postoperative pain assessment 
None or mild discomfort                                 2 
Moderate to severe pain controlled with 
IV analgesics                                                   1 
Persistent severe pain                                     0 
 
➢ Postoperative emetic symptoms 
None or mild nausea with no active 
vomiting                                                        2 
Transient vomiting or retching                      1 
Persistent moderate to severe nausea 
and vomiting                                                  0 
Total score 14 
 
 
 
Sampling : 
Patients in the three groups will undergo blood sampling for measurement of cortisol 
and catecholamine level  using ELISA technique 3 times : 
• 30 min. pre –op. 
• 1 hour after the start of the procedure. 

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• 2 hour after the end of the procedure. 
• 6 hours after the end of the procedure  
 Pain assessment : 
Pain score to surgery will be assessed according to the  VAS pain score sheet as 
follows : 
• Immediately after the admission to recovery room. 
• 15 minutes following the admission to recovery room. 
• 2 hours after the end of the procedure. 
• 6 hours after the end of the procedure. 
• Time to 1st analgesia request. 
• 24 hour post – operative analgesia requirement. 
• Intra-operative fentanyl consumption. 
 
 
Primary outcomes (Most important outcomes to be assessed) : 
 
Assessment of postoperative pain with each technique. 
 
 
Secondary outcome parameters (other outcomes to be assessed) : 
 
• Assessment of stress response with each technique through measuring cortisol 
and catecholamine levels. 
• Hemodynamic Parameters regarding blood pressure and heart rate. 
• Incidence of nausea and vomiting post – operative. 

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• Modified Aldrete score. 
• Time to hospital discharge. 
 
STATISTICAL METHODS: 
 
Sample size calculation was done using the comparison of postoperative pain score 
between RSB, local infiltration and control groups as it was the primary outcome of 
our study. As reported in previous publication (6,7) the mean ± S.D. of postoperative 
pain score in RSB group was 4.65 ± 2.1, while in local infiltration group it was 
5.45±1.9 and in control group it was 7.1±1.1. We calculated that a sample size of 23 
in each group will be able to detect a one  unit difference between the groups with 
80% power at α = 0.05 level using analysis of variance test (one way ANOVA test) 
for independent samples. The sample size calculation was done using the G*Power© 
software (Institut für Experimentelle Psychologie, Heinrich Heine Universität, 
Düsseldorf, Germany) version 3.1.9.2. To allow for drop-outs, 25 patients in each 
group were recruited. 
The statistical analysis was performed using IBM SPSS® Statistics version 22 
(IBM® Corp., Armonk, NY, USA). Numerical data were expressed as mean and 
standard deviation or median and range as appropriate. The qualitative data were 
expressed as frequency and percentage. The relation between qualitative variables 
was examined using either Pearson's Chi-square test or Fisher's exact test.   
The quantitative continuous data were tested for normality using the Kolmogorov-
Smirnov test and the Shapiro-Wilk test. The comparisons between the three groups 
were done using either analysis of variance (ANOVA) for normally distributed 
quantitative variables or Kruskal-Wallis test (non-parametric ANOVA) for none-
normally distributed data then post-hoc test" was used for pair-wise comparison. 
ANOVA with repeated measures (for normally distributed data) or Friedman test 
(non-parametric ANOVA with repeated measures for non- normally distributed data) 
was used to compare more than two consecutive measures of numerical variables 

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followed by post hoc tests for pairwise comparisons of repeated readings. Due to 
multiple comparisons, the p-value was corrected using the Bonferroni method.  
The time to first analgesia request analysis was done using the Kaplan-Meier method 
and comparison between groups was done using the log-rank test. The Cox-
regression method was used to calculate the hazard ratio (HR) for risk estimation 
with its 95% confidence interval (CI). All tests were two-tailed. A p-value < 0.05 
was considered significant. 
Source of funding: 
 
Will be provided by Theodor Bilharz Research Institute. 
 
 
 Time plan: 
 
Starting date: August 2017. 
 
References : 
 
1.  Merskey H. Classification of chronic pain: description of chronic pain syndromes 
and definitions of pain terms. Monograph for the subcommittee on Taxonomy 
International Association for the study of pam. Pain Suppl Vol 3. Amsterdam: 
Elsevier Science 1986. 
2.  Schurrm J, Gordon D B, Pellino T A, et al.,:  Continuous local anesthetic 
infusion for pain management after outpatient inguinal herniorrhaphy. Surgery 136: 
761–769. 2004 
3.    Dolan J, Lucie P, Geary T, et al.,: The rectus sheath block for laparoscopic 
surgery in adults: a comparison between the loss of resistance and ultrasound guided 
techniques. Anesthesia; 62: 302. 2007. 
4.   Sites BD and Brull R. Ultrasound guidance in peripheral regional anesthesia: 
philosophy, evidence-based medicine, and techniques. Current Opinion in 

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Anesthesiology; 19: 630-9. 2006. 
5. Paul F. White. New Criteria for Fast-Tracking After Outpatient Anesthesia: A 
Comparison with the Modified Aldrete’s Scoring System. Anesth Analgesia criteria 
for fast tracking ;88:1069–72. 1999. 
6. Charlton S GJ. Cochrane Database of Systematic Reviews Perioperative 
transversus abdominis plane (TAP) blocks for analgesia after abdominal surgery 
(Review) Perioperative transversus abdominis plane (TAP) blocks for analgesia 
after abdominal surgery (Review). Cochrane Database Syst Rev Art. 2010;(12):1–
59.  
7. 
Flack SH, Martin LD, Walker BJ  et al. Flack abstract. Available from: 
http://www2.pedsanesthesia.org/meetings/2011winter/syllabus/submissions/abstract
s/wapd/GA30.pdf.