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post - operative analgesia is important after surgery to avoid various complications such as venous thromboembolism , respiratory complications and prolonged hospital stay
. substantial pain and discomfort are anticipated after caesarean delivery ; hence , analgesic regimen should ensure effective and safe analgesia . the transversus abdominis plane ( tap )
is the fascial plane between the internal oblique and transversus abdominis muscle containing the thoracolumbar nerves t10 to l1 .
the introduction of local anaesthetic in this plane blocks these nerves ( t10 to l1 ) .
we hypothesised that ultrasonography ( usg)-guided tap block reduces requirement of opioids and provides effective and adequate analgesia .
after obtaining approval from the institutional ethics committee and written informed consent , sixty american society of anesthesiologists ( asa ) i and ii patients posted for elective and emergency caesarean section were included in a prospective , randomised , double - blind , controlled clinical trial which was completed over a period of 6 months .
patients were excluded from the study if they refused , had contraindications to spinal anaesthesia , required general anaesthesia for the surgery , had local anaesthetic sensitivity or were morbidly obese .
patients were randomised by sealed envelope technique to undergo usg guided tap block with 0.5% ropivacaine ( n = 30 ) 15 ml on either side  group s or usg guided tap block with 0.9% normal saline ( n = 30 ) 15 ml on either side  group c. the allocation sequence was generated by random number table .
all patients also received injection paracetamol 1 g intravenously ( iv ) at the end of the surgery .
tap block was administered by the posterior approach using the sonosite nanomaxx ultrasonography machine with a linear array transducer probe ( 613 mhz ) .
pain severity was assessed by an investigator blinded to the allotment every 2 , 4 , 6 , 8 , 12 , 18 and 24 h. it was measured using visual analogue score ( vas ) ( 0 = no pain and 10 = worst possible pain ) .
rescue analgesia was given to patients on demand or when vas was more than 4 in the form of iv tramadol 2 mg / kg .
the parameters studied and compared in both the groups were time to first request for analgesic , total tramadol requirement in 24 h and vas at 2 , 4 , 6 , 8 , 12 , 18 , 24 h. for sample size calculation , we considered that a clinically important reduction in 24 h tramadol consumption would be 25% absolute reduction .
we calculated that 28 patients per group would be required for an experimental design incorporating two equal - sized groups , using 0.05 and 0.2 alpha and beta errors . to minimise any effect of data loss
chicago : spss inc . ) demographic data were analysed using student 's t - test or fisher 's exact test as appropriate .
the comparison of total tramadol requirement , time to first analgesic administration and vas between the two groups was done by paired t - test .
sixty patients were recruited in the study , of these thirty were randomised to undergo tap block with 0.5% ropivacaine and remaining 30 with placebo . demographic profile , pulse ,
demographic data were comparable in both groups time to first analgesic administration ( tramadol ) was prolonged significantly in group s ( mean - 9.53 h ) as compared to group c ( mean - 4.1 h ) , p = 0.0163 [ figure 1 ] .
time for rescue analgesia in hours in patients receiving tap block with 0.5% ropivacaine ( group s ) , the requirement for analgesic significantly reduced as compared to those who received the placebo block ( group c ) .
mean tramadol requirement for group s was 140 mg and for the placebo group ( group c ) was 246.66 mg , which was statistically significant ( p = 0.000000439 ) [ figure 2 ] .
mean tramadol requirement in milligrams in the first 24 h after caesarean delivery vas was noted at 2 , 4 , 6 , 8 , 12 , 18 and 24 h. vas was reduced after tap block with 0.5% ropivacaine for the first 810 h post - operatively as compared to patients receiving placebo block [ figure 3 ] .
the results of our study show that tap block when used as part of multimodal analgesic regimen after caesarean delivery delayed time for rescue analgesia , reduced requirement of opioid analgesic and decreased vas .
multimodal analgesia provides better results by combining various drugs with different duration , and onset of action also reduces the side effects of individual drugs .
various studies have been conducted in which opioids have been used iv , intrathecally and also epidurally .
however , opioids are associated with complications such as respiratory depression , pruritus , sedation , nausea and vomiting .
non - steroidal anti - inflammatory drugs are commonly used but are associated with complications such as bleeding tendencies , uterine atony and gastrointestinal bleeding .
ketamine can also be used , but it affects interaction between the mother and the new - born .
diclofenac , indomethacin and acetaminophen suppositories have also been used for post - operative pain relief .
epidural analgesia is a good alternative for post - operative pain relief , but the gravid uterus increases the chances of dural and vascular puncture , also making it difficult to identify the space .
infiltration of local anaesthetic is also used to provide pain relief , but it is not effective for prolonged analgesia .
he described it as block delivering local anaesthetics in the tap using the anatomical landmarks ( iliac crest ) by first identifying the lumbar triangle of petit . in 2007 , hebbard et al .
the usg probe was placed transverse to the abdominal wall which made the three muscle layers distinctly visible after which the probe was moved to the mid - axillary line just above the iliac crest ( i.e. , over the triangle of petit ) .
tap block has been used for various abdominal procedures other than caesarean section such as large bowel resection , open / laparoscopic appendectomy , total abdominal hysterectomy , laparoscopic cholecystectomy , open prostatectomy , abdominoplasty with or without flank liposuction , inguinal hernia and iliac crest bone graft .
the tap has poor vascularity , and hence the action is prolonged and not associated with any major complications .
we used the usg - guided technique to avoid complication more common with the blind approach .
in addition , it gives a real - time picture and chances of failure are reduced .
a study using usg - guided tap block with 0.5% ropivacaine after caesarean section was associated with reduction in total morphine use in 24 h in the active group ( median 18 mg ) compared with the placebo group ( median 31.5 mg ) .
vass also reduced in the active group compared to placebo group ( 96 mm vs. 77 mm p = 0.008 ) .
similarly , a study was conducted in 2008 using tap block after caesarean delivery by the blind approach , with 1.5 mg / kg ropivacaine ( to a maximal dose of 150 mg ) or saline on each side .
the study confirmed the usefulness of tap block as seen by the reduced the vas and requirement for morphine ( 66  26 mg vs. 18  14 mg , p < 0.001 ) .
two similar studies of tap block were conducted in asa i and ii patients undergoing elective caesarean section under spinal anaesthesia using 20 ml of 0.25% bupivacaine or levobupivacaine .
the studies revealed that pain scores were lower and time of demand for first analgesia was significantly longer in study groups compared to control ( no drug ) groups .
another study was conducted using 20 ml of 0.375% ropivacaine on either side , which included asa ii patients undergoing caesarean section under spinal anesthesia ; reduction in mean vas score ( p < 0.001 ) and reduced opioid requirement were observed . in our study , we used usg - guided technique for tap block to avoid the complications of blind technique .
we used 0.5% ropivacaine 30 ml and also took care not to exceed the toxic dose that is , 3 mg / kg . a study conducted in patients undergoing caesarean section using ropivacaine
, 0.375% , 40 ml for tap block for post - operative analgesia showed that the pain scores and opioid consumption were similar between the two groups .
the groups consisted of one that received tap block with ropivacaine ( n = 50 ) and the other , placebo ( n = 50 ) . the mean ( standard deviation ) vas on movement at 24 h in the ropivacaine and placebo groups was 3.4 ( 2.4 ) and 3.2 ( 2.2 ) cm , respectively , p = 0.47 .
mckeen et al . in 2014 conducted a similar study using tap block and observed no significant difference in opioid consumption ( p = 0.2 ) and vas ( p = 0.61 ) .
obese patients were excluded as the block was difficult to perform , and assessment was limited to only 24 h post - operatively ( but pain severity reduced even in control group by this time ) .
usg - guided bilateral tap block with 0.5% ropivacaine ( total 30 ml ) reduces the postoperative opioid analgesic consumption in caesarean section patients .
background and aims : transversus abdominis plane ( tap ) block is a fascial plane block providing post - operative analgesia in patients undergoing surgery with infra - umbilical incisions . 
 we evaluated analgesic efficacy of tap block with ropivacaine for 24 h after caesarean section through a pfannenstiel incision.methods:sixty patients undergoing caesarean section under spinal anaesthesia were randomised to undergo tap block with ropivacaine ( n = 30 ) versus control group ( n = 30 ) with normal saline , in addition to standard analgesia with intravenous paracetamol and tramadol . at the end of the surgery , 
 ultrasound - guided tap plane block was given bilaterally using ropivacaine or normal saline ( 15 ml on either side ) . 
 each patient was assessed post - operatively by a blinded investigator at regular intervals up to 24 h for visual analogue score ( vas ) and requirement of analgesia . 
 spss version 18.0 software was used . 
 demographic data were analysed using student 's t - test and the other parameters using paired t-test.results:tap block with ropivacaine compared with normal saline reduced post - operative vas at 24 h ( p = 0.004918 ) . 
 time for rescue analgesia in the study group was prolonged from 4.1 to 9.53 h ( p = 0.01631 ) . 
 mean requirement of tramadol in the first 24 h was reduced in the study group.conclusion:us guided tap block after caesarean section reduces the analgesic requirement in the first 24 h.