Year : 2018 | Volume
| Issue : 2 | Page : 183-189
Preperitoneal postcesarean section bupivacaine analgesia: Comparison between dexamethasone and dexmedetomidine as adjuvants
Alaa Mazy1, Mona Gad1, Mohamed Bedairy2
1 Department of Anesthesia and Surgical Intensive Care, Faculty of Medicine, Mansoura University, Mansoura, Egypt
2 Department of Obstetrics and Gynecology, Faculty of Medicine, Mansoura University, Mansoura, Egypt
Dr. Alaa Mazy
Department of Anesthesia and Surgical Intensive Care, Faculty of Medicine, Mansoura University, Mansoura
Source of Support: None, Conflict of Interest: None
|Date of Web Publication||9-Mar-2018|
Background: The peritoneal wound is frequently neglected during laparotomy. The preperitoneal local anesthetics and many adjuvants were effective for postcesarean analgesia. Analgesia may involve somatic and autonomic components. The preperitoneal bupivacaine and the promising adjuvants dexamethasone or dexmedetomidine were compared in this study.
Patients and Methods: Sixty patients subjected to a cesarean section (CS) under general anesthesia divided into two groups using a bolus of preperitoneal bupivacaine 0.7 mg/kg with either 1ug/kg dexmedetomidine (Group P) or 8 mg dexamethasone (Group D). The time to the first analgesic request was the primary outcome.
Results: There was a significantly prolonged time to the first analgesic request in the Group P than the Group D and less required preperitoneal injections in the Group P, also pain assessed by Numerical Rating Scale (NRS) was lower in the Group P than the Group D after 6 h postoperatively up to 24 h.
Conclusions: Dexmedetomidine provided better analgesia than dexamethasone as an adjuvant to preperitoneal bupivacaine post-CS.
Keywords: Analgesia; cesarean section; dexamethasone; dexmedetomidine; preperitoneal
|How to cite this article:|
Mazy A, Gad M, Bedairy M. Preperitoneal postcesarean section bupivacaine analgesia: Comparison between dexamethasone and dexmedetomidine as adjuvants. Saudi J Anaesth 2018;12:183-9
|How to cite this URL:|
Mazy A, Gad M, Bedairy M. Preperitoneal postcesarean section bupivacaine analgesia: Comparison between dexamethasone and dexmedetomidine as adjuvants. Saudi J Anaesth [serial online] 2018 [cited 2018 Mar 24];12:183-9. Available from: http://www.saudija.org/text.asp?2018/12/2/183/226986
| Introduction|| |
Cesarean section (CS) delivery is one of the most common operative procedures performed worldwide. Post-CS analgesia enhances early ambulance and mother's ability for breastfeeding and optimal care for her infant immediately postpartum. Unexpectedly, the incidence of acute pain after CS is still high. Post-CS pain treatment involves different strategies; the most challenging target is reducing opioid consumption that may be achieved by extended nerve blocks implementing the enhanced recovery protocols. Locoregional analgesia represents a component of the multimodal pain management approach that showed benefits after CS. One of these techniques is the wound infiltration that showed the possibility to minimize the use of opioids post-CS. Evidence-based data recommend the use of wound catheter local anesthetic (LA) infusions.
The preperitoneal catheter technique is simple, where the surgeon directly places a multiorifice catheter at the end of the procedure. It is technically efficient with no failure rate, offers good analgesia with reduced opioids consumption; in addition, it can be used for several days even on ambulatory basis using portable pumps.
Pain is a complex multifactorial phenomenon. Therefore, the combination of different analgesic techniques and medications acting on different target sites may offer excellent dynamic pain relief and reduced adverse effects. Regional bupivacaine alone is short-lived. Adjuvants may be used to prolong the LA analgesia. Nonsteroidal anti-inflammatory (NSAID) utilization showed efficacy. The administration of steroids was promising. Dexmedetomidine perineural administration prolonged motor block by 87% and increased the time to the first analgesic request by 70% compared with LA alone.
We proposed that preperitoneal dexamethasone and dexmedetomidine can extend post-CS bupivacaine analgesia.
| Patients and Methods|| |
This is a randomized double-blind study that was conducted on 60 patients scheduled for elective CS under general anesthesia through Pfannenstiel incision including different parity, presentation, body mass index, and American Society of Anesthesiologists status I-II. This study was approved by the institutional research board (code number R/16.03.90), and the Clinical Trials registry number is PACTR201701002007277.
Exclusion criteria were patient refusal, the patients with toxemia of pregnancy, antepartum hemorrhage, relevant drug allergy, drug abuse, psychiatric disorders, communication difficulties, and inability for peritoneal closure.
Using a priori G-power analysis with the time till the first analgesic request as the primary objective, based on 95% confidence interval, type 1 error protection of 0.05 and an effect size convention of 0.8 yield a total sample size of 56 (28 patients in each group) produced a power of 90%. However, we recruited sixty cases to overcome the possibility of drop out cases about 5% (thirty patients in each group).
All patients were evaluated for medical history, laboratory data, clinical physical, and airway examination, training for Numerical Rating Scale (NRS), consent signing, and preoperative hydration using 500 ml Ringer's solution.
Patients were randomly allocated using sealed envelopes into two groups according to the adjuvant used. During repositioning of the exteriorized uterus, the envelope is opened by an anesthetist not involved in the anesthetic management during surgery or postoperative assessments to prepare the study drugs in the anesthesia room next to the operating theatre. A mixture of 20 ml contains bupivacaine 0.7 mg/kg with the assigned adjuvant either:
- Group (P): Added 1 microgram (μg) /kg Dexmedetomidine (Precedex ®, Hospira, Inc., Lake Forest, IL), or
- Group (D): Added 8 mg dexamethasone.
All participants received standardized general anesthesia, included induction of anesthesia with propofol (2 mg/kg), succinyl choline (1 mg/kg), and endotracheal intubation. Maintenance using atracurium and sevoflurane 1%–2% in 60% air in oxygen. Intravenous nalbuphine 0.3 mg/kg after delivery, maximum of 20 mg.
Before wound closure, the anesthetist will prepare an epidural catheter by doing perpendicular perforations in addition to the already present ones, using syringe needle one centimeter apart in a length suitable for the wound.
After the closure of the peritoneum, the obstetrician (single, experienced clinician) will insert the catheter on the peritoneum (under the transversalis fascia) through a Touhi needle few centimeters from the lower edge of the wound. A bolus of 10 mL saline solution is injected as a test, then the catheter is secured to the skin. After closure of the above layers till the skin, the blindly prepared mixture is injected through the bacterial filter before wound dressing to assess for any leakage.
On patient first request for analgesia, 20 ml bupivacaine 0.25% is injected through the preperitoneal catheter. After 20 min, pain is assessed by Numerical rating scale (NRS) from 0 to 10, with 10 as the worst pain. If NRS ≥4, a NSAID-ketorolac (Ketolac ® Amriya. Alexandria) 30 mg intravenous is given. If pain still ≥3, nalbuphine 5 mg increments are given until NRS is ≤2. Then, preperitoneal injection to be repeated again if NRS is ≥4. The time to the first analgesic request, the number of preperitoneal injections, ketorolac and nalbuphine consumption were recorded within the first 24 h postoperatively. Mean arterial blood pressure, heart rate (HR), and (NRS) were assessed every 2 h for 12 h, then every 6 h till 24 h. The quality of sleep was assessed after 24 h using 0–10 visual analog scale, with 10 is the worst.
Side effects such as nausea, vomiting, and sedation were recorded through the first 24 h postoperatively. Anti-emetics; Metoclopramide 10 mg. If no response, Ondansetron 4 mg was given.
The incidence of wound infection through 2 weeks postoperatively was recorded.
The statistical analysis of data was done using Statistical Package for Social Science (SPSS Inc, Chicago, IL, USA) program version 16. To test the normality of data distribution, Shapiro–Wilk test was used. The unpaired Student's t-test was used for comparisons of parametric variables. For nonparametric data, the Mann–Whitney test was used. Chi-square test was used for qualitative data. Data are displayed as mean (± standard deviation) for parametric data, frequency, and proportion for nonparametric data. A difference in probability (P) <0.05 was considered statistically significant at a confidence interval 95%.
| Results|| |
A total of 60 patients were enrolled, allocated, and analyzed in this study. The peritoneum was closed successfully in all patients. There were no significant differences for patient's characteristics [Table 1].
|Table 1: Patients demographic data in mean±standard deviation, and postoperative analgesia characteristics in median (range)|
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Results showed a highly significant prolonged time to the first analgesic request in Group P in relation to Group D [Table 1]. During the first 24 h postoperatively, the number of preperitoneal required injections was significantly less in Group P [Table 1]; where three-quarters (74.2%) of the patients in Group P required one injection only [Figure 1], while 95% of patients in Group D required 2–3 injections. The quality of sleep was not different between the groups [Table 1].
|Figure 1: The frequencies of required preperitoneal injections in the first 24 h postoperatively|
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Ketorolac and nalbuphine dose requirements were not different between the groups (P > 0.05), but most of the patients (two-thirds) required only 30 mg ketorolac in both groups. A quarter of the patients required no ketorolac of Group P, while a quarter required 60 mg dose of Group D [Figure 2].
|Figure 2: Ketorolac required dose frequencies in the first 24 h postoperatively|
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It is observed that two-thirds (about 66%) of all the patients showed opioid free analgesia postoperatively [Figure 3].
|Figure 3: Dose requirements frequencies of nalbuphine in mg during the first 24 h postoperatively|
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Pain scores (NRS) were significantly lower in Group P than Group D starting 6 h postoperatively up to 24 h [Figure 4]. In all patients, the mean pain scores ranged from 1.45 to 3.
|Figure 4: The mean numerical pain rating scale (NRS) in the first 24 h postoperatively. *Significant difference between Group P and D. P 0.05|
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Hemodynamically, the HR was significantly lower in Group P only in the first 6 h postoperatively, while the MBP showed no significant difference [Figure 5]
|Figure 5: The mean heart rate in beat/min. and the mean arterial blood pressure in mmHg during the first 24 h postoperatively. *Significant HR difference between Group P and D. P < 0.05|
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There was no significant difference (P = 0.76) in the incidence of vomiting between Group P (13.9%) and Group D (10.3%) or doses of antiemetics. Sedation was minimal in both groups. There is no reported wound infection.
| Discussion|| |
This study showed an effective postcesarean preperitoneal analgesia that was superior using dexmedetomidine (P) than dexamethasone (D) as an adjuvant. Only few studies recently reported improved analgesia after preperitoneal LA with dexamethasone  as well as dexmedetomidine. Preperitoneal bupivacaine provided also effective analgesia and enhanced postoperative recovery. Although preperitoneal analgesia is a promising simple technique, yet there is conflicting reports about its efficacy. The explanation of this conflict may be related to single injection rather than infusion, and the suprafascial rather than the more effective subfascial preperitoneal position between transversalis fascia and the peritoneum, and it may also be related to the dose.
The peritoneal contribution to preperitoneal analgesia
The exact mechanism of preperitoneal analgesia is not defined. Both somatic and visceral anti- nociceptive effects may be implicated. LA in the preperitoneal space act locally on specific peritoneal pain receptors, blocking afferents of the fascia and the peritoneum thus reducing pain, hyperalgesia, and diaphragmatic dysfunction.
Anatomically, the abdominal nerves communicate extensively, encroaching medially to enter the rectus sheath through the lateral margin of the linea semilunaris, then approach the posterior surface of rectus abdominis as a plexus that run craniocaudally around the deep inferior epigastric artery. Below the semicircular line of Douglas, the rectus sheath is deficient, leaving the rectus muscle in direct contact with the fascia transversalis and the peritoneum. When a contrast medium is injected preperitoneally, it remained in the space between transversalis fascia and peritoneum. The parietal peritoneum and overlying muscles are innervated by the segmental spinal nerves from T7 to L1. The visceral peritoneum is innervated by the vagus nerves and sympathetic fibers. Its stimulation mediates poorly localized discomfort and profound reflex autonomic and emotional reactions. Visceral sensations reach the brain mostly through afferent vagal fibers.
Indeed, the peritoneum is an active organ, not a passive container. If the peritoneum is manipulated during laparotomy, it reacts by initiating acute local and systemic inflammatory response involving various mediators that act directly on the vagal afferents mediating pain. Furthermore, these mediators induce peripheral and central sensitizations contributing to pain and hyperalgesia.
The prevention of neuron sensitization by multimodal analgesia reduces postsurgical pain, an effect that may extend after stopping LA “preventive analgesia.” That may explain extended lower pain scores in Group P in this study 24 h postoperatively. Therefore, local preperitoneal or intraperitoneal chemical afferentectomy may serve to block vagal afferents thus reducing sensitization., Consequently, that may contribute to enhanced patients recovery, where the somatic and peritoneal abdominal wounds predispose to autonomic disturbance, catabolic response, fatigue, anorexia, and disturbed sleep rhythm postoperatively.
Pharmacologic contribution to preperitoneal analgesia
In addition to block of nociception, LAs possess also a systemic anti-inflammatory effect, and block the visceral sensitization at medullar neurons. Glucocorticoids  as well as dexmedetomidine  provide also an anti-inflammatory effect.
The exact mechanism of topical dexmedetomidine (P) analgesia is not well understood. It may extend the duration of LA by local vasoconstriction through an action on α2 adrenoreceptors subtypes. Peripheral α2 receptors are expressed on peripheral sensory neurons and are involved in peripheral analgesia. Dexmedetomidine (P) alone did not provide a significant sensory or motor blockade, but potentiates LA action about 75%, due to blockade of the hyperpolarization-activated cation (Ih) current, not through α2 action. Similar to clonidine, (P) peripheral analgesia may be through release of an encephalin-like substance.
Comparison with other analgesia modalities
Different modalities of post-CS analgesia were applied, but opioids still the gold standard, tranversus abdominis plane (TAP) block is the most investigated, while wound infiltration requires further evaluation. Intrathecal morphine efficiently reduces post-CS pain but involves numerous side effects.
Comparative to other regional analgesic techniques for laparotomy, the epidural is the gold standard but may not be the first choice post-CS owing to possible delayed ambulation of mothers. Furthermore, it may be associated with hypotension, urine retention, inadequate distribution, and epidural hematoma. Particularly with the presence of contraindications to epidural, the preperitoneal analgesia became an interesting alternative with equivalent pain control and lower complications.
Post-CS analgesia using TAP block may be equally effective with wound infiltration, but lacking visceral effects and may be associated with possible visceral damage and high-plasma concentration of LA.
In agreement with other investigators, applying multimodal analgesia and preperitoneal technique in this study are associated with beneficially opioid-free analgesia in about two-thirds of patients.
We used multiorifice epidural catheter where the standard catheter is not available in our country. The preperitoneal infusion was not applied in this study because the high pressure pumps also not available, and for comparison between adjuvants as reflected by the time to the first analgesic request. The extended effects due to adjuvants may preclude infusion.
There is no standard preperitoneal regimen. In this study, we used 20 ml bupivacaine 0.25% provided a median pain scores ranged 1.45–3. No patients had score zero also using 0.25% bupivacaine at 6 ml/h. Ozturk et al. recorded a score zero using 0.2% ropivacaine at 10 ml/h.
Despite the promising preperitoneal analgesia, a limitation raised, where the required peritoneal closure may be associated with more pain and adhesions compared to non-peritoneal closure. When closure is difficult, alternatively, the preperitoneal tunneled catheter technique can be used.
Our results revealed mild bradycardia in the Group P for the first 6 h compared with Group D. That may correlate with longer analgesia in the Group P, where the first request for analgesia was after 7 h or may be a systemic (P) action. No hypotension or bradycardia was evident using dexmedetomidine in Ayse et al. study in spite of using 2 mcg/kg but in hysterectomy patients.
| Conclusions|| |
This study showed that dexmedetomidine provided better analgesia than dexamethasone as an adjuvant to preperitoneal bupivacaine post-CS. Implementing this technique, opioid-free analgesia could be achieved in two-thirds of patients.
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Conflicts of interest
There are no conflicts of interest.
| References|| |
Tshibangu KC, de Jongh MA, de Villiers DJ, du Toit JJ, Shah SM. Incidence and outcome of caesarean section in the private sector-3-year experience at Pretoria Gynaecological Hospital. S Afr Med J 2002;92:956-9.
Gadsden J, Hart S, Santos AC. Post-cesarean delivery analgesia. Anesth Analg 2005;101 5 Suppl:S62-9.
Marcus H, Gerbershagen HJ, Peelen LM, Aduckathil S, Kappen TH, Kalkman CJ, et al.
Quality of pain treatment after caesarean section: Results of a multicentre cohort study. Eur J Pain 2015;19:929-39.
Bamigboye AA, Hofmeyr GJ. Caesarean section wound infiltration with local anaesthesia for postoperative pain relief-any benefit? S Afr Med J 2010;100:313-9.
Schyns-van den Berg AM, Huisjes A, Stolker RJ. Postcaesarean section analgesia: Are opioids still required? Curr Opin Anaesthesiol 2015;28:267-74.
Macintyre PE, Scott DA, Schug SA, Visser EJ, Walker SM. Acute Pain Management: Scientific Evidence. 3rd
ed. Melbourne, ANZCA & FPM; 2010.
Liu SS, Richman JM, Thirlby RC, Wu CL. Efficacy of continuous wound catheters delivering local anesthetic for postoperative analgesia: A quantitative and qualitative systematic review of randomized controlled trials. J Am Coll Surg 2006;203:914-32.
Woolf CJ; American College of Physicians; American Physiological Society. Pain: Moving from symptom control toward mechanism-specific pharmacologic management. Ann Intern Med 2004;140:441-51.
McCartney CJ, Brull R, Chan VW, Katz J, Abbas S, Graham B, et al
. Early but no long-term benefit of regional compared with general anesthesia for ambulatory hand surgery. J Am Soc Anesthesiol 2004;101:461-7.
Williams BA, Ibinson JW, Mangione MP, Scanlan RL, Cohen PZ. Clinical benchmarks regarding multimodal peripheral nerve blocks for postoperative analgesia: Observations regarding combined perineural midazolam-clonidine-buprenorphine-dexamethasone. Pain Med 2015;16:1-6.
Rackelboom T, Le Strat S, Silvera S, Schmitz T, Bassot A, Goffinet F, et al.
Improving continuous wound infusion effectiveness for postoperative analgesia after cesarean delivery: A randomized controlled trial. Obstet Gynecol 2010;116:893-900.
Romundstad L, Stubhaug A. Glucocorticoids for acute and persistent postoperative neuropathic painwhat is the evidence? J Am Soc Anesthesiol 2007;107:371-3.
Abdallah FW, Brull R. Facilitatory effects of perineural dexmedetomidine on neuraxial and peripheral nerve block: A systematic review and meta-analysis. Br J Anaesth 2013;110:915-25.
Sakamoto B, Harker G, Eppstein AC, Gwirtz K. Efficacy of local anesthetic with dexamethasone on the quality of recovery following total extraperitoneal bilateral inguinal hernia repair: A randomized clinical trial. JAMA Surg 2016;151:1108-14.
Ülgey A, Güneş I, Bayram A, Biçer C, Kurt FM, Müderis İ, et al
. The analgesic effects of incisional levobupivacaine with dexmedetomidine after total abdominal hysterectomy. Erciyes Med J 2015;37:64-8.
Dhanapal B, Sistla SC, Badhe AS, Ali SM, Ravichandran NT, Galidevara I. Effectiveness of continuous wound infusion of local anesthetics after abdominal surgeries. J Surg Res 2017;212:94-100.
Trotter TN, Hayes-Gregson P, Robinson S, Cole L, Coley S, Fell D. Wound infiltration of local anaesthetic after lower segment caesarean section. Anaesthesia 1991;46:404-7.
Larsen KR, Kristensen BB, Rasmussen MA, Rasmussen YH, Weber T, Kristensen B, et al.
Effect of high-volume systematic local infiltration analgesia in Caesarean section: A randomised, placebo-controlled trial. Acta Anaesthesiol Scand 2015;59:632-9.
Cervero F. Visceral versus somatic pain: Similarities and differences. Dig Dis 2009;27 Suppl 1:3-10.
Beaussier M, El'ayoubi H, Rollin M, Parc Y, Atchabahian A, Chanques G, et al.
Parietal analgesia decreases postoperative diaphragm dysfunction induced by abdominal surgery: A physiologic study. Reg Anesth Pain Med 2009;34:393-7.
Rozen WM, Tran TM, Ashton MW, Barrington MJ, Ivanusic JJ, Taylor GI. Refining the course of the thoracolumbar nerves: A new understanding of the innervation of the anterior abdominal wall. Clin Anat 2008;21:325-33.
Ellis H, Lawson A. Anatomy for Anaesthetists. 9th
ed. Oxford: John Wiley & Sons; 2013.
Bielefeldt K, Christianson JA, Davis BM. Basic and clinical aspects of visceral sensation: Transmission in the CNS. Neurogastroenterol Motil 2005;17:488-99.
Kahokehr A, Sammour T, Srinivasa S, Hill AG. Metabolic response to abdominal surgery: The 2-wound model. Surgery 2011;149:301-4.
Koninckx PR, Gomel V, Ussia A, Adamyan L. Role of the peritoneal cavity in the prevention of postoperative adhesions, pain, and fatigue. Fertil Steril 2016;106:998-1010.
Goehler LE, Gaykema RP, Hammack SE, Maier SF, Watkins LR. Interleukin-1 induces c-Fos immunoreactivity in primary afferent neurons of the vagus nerve. Brain Res 1998;804:306-10.
Dirks J, Møiniche S, Hilsted KL, Dahl JB. Mechanisms of postoperative pain: Clinical indications for a contribution of central neuronal sensitization. J Am Soc Anesthesiol 2002;97:1591-6.
Brennan TJ, Kehlet H. Preventive analgesia to reduce wound hyperalgesia and persistent postsurgical painnot an easy path. J Am Soc Anesthesiol 2005;103:681-3.
Lavand'homme P. From preemptive to preventive analgesia: Time to reconsider the role of perioperative peripheral nerve blocks? Reg Anesth Pain Med 2011;36:4-6.
Kfoury T, Mazoit JX, Schumacher M, Benhamou D, Beloeil H. A comparison of different dosages of a continuous preperitoneal infusion and systemic administration of ropivacaine after laparotomy in rats. Anesth Analg 2011;113:617-25.
Kahokehr A, Sammour T, Zargar Shoshtari K, Taylor M, Hill AG. Intraperitoneal local anesthetic improves recovery after colon resection: A double-blinded randomized controlled trial. Ann Surg 2011;254:28-38.
Ness TJ, Piper JG, Follett KA. The effect of spinal analgesia on visceral nociceptive neurons in caudal medulla of the rat. Anesth Analg 1999;89:721-6.
Zargar-Shoshtari K, Sammour T, Kahokehr A, Connolly AB, Hill AG. Randomized clinical trial of the effect of glucocorticoids on peritoneal inflammation and postoperative recovery after colectomy. Br J Surg 2009;96:1253-61.
Kuru S, Bozkirli OB, Barlas AM, Duymus ME, Senes M, Yumusak N, et al.
The preventive effect of dexmedetomidine against postoperative intra-abdominal adhesions in rats. Int Surg 2015;100:87-95.
Yabuki A, Higuchi H, Yoshitomi T, Tomoyasu Y, Ishii-Maruhama M, Maeda S, et al.
Locally injected dexmedetomidine induces vasoconstriction via peripheral a-2A adrenoceptor subtype in guinea pigs. Reg Anesth Pain Med 2014;39:133-6.
Gabriel JS, Gordin V. Alpha 2 agonists in regional anesthesia and analgesia. Curr Opin Anaesthesiol 2001;14:751-3.
Brummett CM, Hong EK, Janda AM, Amodeo FS, Lydic R. Perineural dexmedetomidine added to ropivacaine for sciatic nerve block in rats prolongs the duration of analgesia by blocking the hyperpolarization-activated cation current. J Am Soc Anesthesiol 2011;115:836-43.
Nakamura M, Ferreira SH. Peripheral analgesic action of clonidine: Mediation by release of endogenous enkephalin-like substances. Eur J Pharmacol 1988;146:223-8.
Kerai S, Saxena KN, Taneja B. Post-caesarean analgesia: What is new? Indian J Anaesth 2017;61:200-14.
] [Full text]
Dahl JB, Jeppesen IS, Jørgensen H, Wetterslev J, Møiniche S. Intraoperative and postoperative analgesic efficacy and adverse effects of intrathecal opioids in patients undergoing cesarean section with spinal anesthesia a qualitative and quantitative systematic review of randomized controlled trials. J Am Soc Anesthesiol 1999;91:1919.
Chen SY, Liu FL, Cherng YG, Fan SZ, Leighton BL, Chang HC, et al.
Patient-controlled epidural levobupivacaine with or without fentanyl for post-cesarean section pain relief. Biomed Res Int 2014;2014:965152.
Nimmo SM. Benefit and outcome after epidural analgesia. Contin Educ Anaesth Crit Care Pain 2004;4:44-7.
Kehlet H, Kristensen BB. Local anesthetics in the surgical wound – Is the pendulum swinging toward increased use? Reg Anesth Pain Med 2009;34:389-90.
Telnes A, Skogvoll E, Lonnée H. Transversus abdominis plane block vs. wound infiltration in Caesarean section: A randomised controlled trial. Acta Anaesthesiol Scand 2015;59:496-504.
Griffiths J, Barron F, Grant S, Bjorksten A, Hebbard P, Royse C. Plasma ropivacaine concentrations after ultrasound-guided transversus abdominis plane block. Br J Anaesth 2010;105:853-6.
Ozturk E, Yilmazlar A, Coskun F, Isik O, Yilmazlar T. The beneficial effects of preperitoneal catheter analgesia following colon and rectal resections: A prospective, randomized, double-blind, placebo-controlled study. Tech Coloproctol 2011;15:331-6.
Pietrantoni M, Parsons MT, O'brien WF, Collins E, Knuppel RA, Spellacy WN. Peritoneal closure or non-closure at cesarean. Obstet Gynecol 1991;77:293-6.
Charyshkin AL, Yakovlev SA, Demin VP. Preperitoneal blockade in the treatment of patients with perforated gastroduodenal ulcers and peritonitis. Int J Biomed 2016;6:114-8.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]