Local Wound Infiltration Versus Caudal Block on Wound Infection and Healing in Paediatrics Inguinal Herniotomy
Condition: Healing Surgical Wounds
MeSH terms: Wound Infection; Wounds and Injuries; Surgical Wound
Study type: Interventional

Summary: 
      The aim of the present study is to assess effect of local wound infiltration in comparison
      with caudal block by bupivacaine 0.25% after inguinal herniotomy in pediatrics on: Wound
      infection and healing (primary outcome) and postoperative analgesia (secondary outcome).
    

Detailed description: 
      THE EFFECT OF LOCAL WOUND INFILTERATION VERSUS CAUDAL BLOCK ON WOUND INFECTION AND HEALING
      AFTER INGUINAL HERNIOTOMY IN PAEDIATRICS

      INTRODUCTION Since the introduction of cocaine in 1884, local anesthetics have been used as a
      mainstay of pain management. However, numerous studies over the past several decades have
      elucidated the supplemental role of local anesthetics as antimicrobial agents. In addition to
      their anesthetic properties, medications, such as: bupivacaine and lidocaine have been shown
      to exhibit bacteriostatic, bactericidal, fungistatic, and fungicidal properties against a
      wide spectrum of microorganisms.(1) Johnson et al.(2)made a comprehensive literature search
      using MEDLINE 1950-present for in vitro and in vivo studies pertaining to the antimicrobial
      activity of various local anaesthetics on a broad range of bacterial and fungal pathogens.
      Studies testing the effect on microbial growth inhibition of local anaesthetics alone and in
      combination with other agents, such as: preservatives and other medications, as well as the
      effect of conditions, such as: concentration and temperature were included for review.
      Evidence suggests that local anesthetics as a class possess inherent antimicrobial properties
      against a wide spectrum of human pathogens. Limited studies attribute the mechanism of action
      of antimicrobial activity of local anesthetics to a disruption of microbial cell membrane
      permeability, leading to leakage of cellular components and subsequent cell lysis.(2)
      Multiple local anesthetics at concentrations typically used in the clinical setting (e.g.:-
      bupivacaine 0.125%-0.75%; lidocaine 1%-3%) inhibit the growth of numerous bacteria and fungi
      under various conditions. Different local anesthetics showed various degrees of antimicrobial
      capacity; bupivacaine and lidocaine, for example, inhibit growth to a significantly greater
      extent than does ropivacaine.(2) In 1943 Lofgren (3) developed lidocaine. This was an amide
      and had a low risk of allergic reactions in comparison to ester local anesthetics. This was
      followed by mepivacaine (1957), prilocaine (1960), bupivacaine (1963), ropivacaine (1997) and
      levobupivacaine (2000).(3) Bupivacaine has been used in clinical practice for more than 40
      years. It is remarkably stable in solution and is commercially available in 0.25% and 0.5%
      solutions (with and without epinephrine). Spinal heavy bupivacaine (0.5% bupivacaine + 6%
      glucose) is also manufactured. It is four times more potent than lidocaine. Therefore, 0.25%
      bupivacaine is equipotent with 1% lidocaine. Bupivacaine is particularly cardiotoxic and
      should never be used in Biers blocks. Bupivacaine binds tightly to tissues and thus has a
      long duration of action (up to 24 hours in some cases). Adding epinephrine will decrease its
      toxicity by delaying the drug absorption but, will have minimal effect on the duration of the
      block.(3)

      The recommended maximum safe doses of bupivacaine are as follows:

      BUPIVACAINE WITHOUT EPINEPHRINE ------- 2.0 mg/kg BUPIVACAINE WITH EPINEPHRINE ------- 2.5
      mg/kg.(3) Caudal anesthesia is one of the most used-popular regional blocks in children. This
      technique is a useful adjunct during general anesthesia and for providing postoperative
      analgesia after infraumbilical operations. The quality and level of the caudal blockade is
      dependent on the dose, volume, and concentration of the injected drug.(4) Prophylactic
      analgesia with local anesthetics is an attractive concept, especially in pediatric practice,
      because the evaluation of pain can be very challenging in young children.(5) In contrast to
      opioids, local anesthetics can be administered safely, and in recent guidelines regional
      anaesthesia is accepted as the cornerstone of post-operative pain relief in the pediatric
      patients.(6) Although regional anaesthesia holds a good safety record overall, the global
      experience with pediatric regional anaesthesia is still quite low; even the most commonly
      performed procedure, caudal block, represents only 2.5% of all central neuroaxial blocks
      performed.(7,8) Determining the risk-benefit ratio is rather difficult for techniques that
      are relatively rarely performed. Wound infiltration can produce reliable analgesia for
      superficial skin surgery. Infiltration itself is extensively used by pediatricians, surgeons
      and emergency physicians for skin laceration repair or minor superficial surgery.(5) Several
      studies have compared the local anesthesia so far, including: ilio-inguinal and
      iliohypogastric nerve block plus subcutaneous injection by the surgeon against the caudal
      anesthesia.(9,10) But to our knowledge, there is still no study comparing the local wound
      infiltration by itself and caudal anesthesia for postoperative analgesia as regard their
      effect on wound infection and healing.

      AIM OF THE WORK The aim of the present study is to assess effect of local wound infiltration
      in comparison with caudal block by bupivacaine 0.25% after inguinal herniotomy in pediatrics
      on: Wound infection and healing (primary outcome) and postoperative analgesia (secondary
      outcome).

      PATIENTS After approval of ethical committee faculty of medicine, University of Alexandria, a
      prospective interventional concealed randomized clinical study which will include 50 children
      (calculated by department of community medicine) aged 2 months-1 year admitted to the
      Pediatrics Surgery Department of Alexandria University Hospitals for elective inguinal
      herniotomy surgery, and an informed written consent will be taken from the parents or the
      guardians.

      All patients will be selected to be grade I or II according to American Society of
      Anesthesiologists (ASA) classification

      The patients will be classified randomly into two groups using closed envelope technique, 25
      patients each:

      Group L: 25 patients will receive 1mg/kg bupivacaine 0.25% (diluted as 1ml bupivacaine + 1ml
      normal saline) by local infiltration in the wound before closure of the skin and
      subcutaneous.

      Group C: 25 patients will receive caudal block with 1mg/kg bupivacaine 0.25%.

      Exclusion criteria included:

        -  History of developmental delay or mental retardation.

        -  Diabetes mellitus type I.

        -  Known allergy or contraindication to any local anesthetics.

        -  Known congenital anomaly in the inguinal region.

        -  Any patient who will develop any infections postoperatively (respiratory infection,
           urinary infection) other than wound infection will be excluded.

      METHODS

      All patients will be subjected to the following:

      A) Pre-operative visit:

      Each patient will be visited the day before surgery for the following:

        -  Proper evaluation by history taking from parents, clinical examination and laboratory
           investigations.

        -  Explanation of the technique of postoperative analgesia to the parents and explain to
           them that the wound will be observed postoperatively for signs of inflammation and
           infection.

      B) Pre-medication:

      Paracetamol suppository 40mg/kg will be given half an hour before surgery.

      C) Anaesthesia:

        -  All patients will be monitored for:

             -  Heart rate (beats/minute) through continuous ECG tracing (lead II).

             -  Non-invasive arterial blood pressure (mmHg).

             -  Arterial oxygen saturation using pulse oximetry (%).

        -  Induction of general anaesthesia will be achieved with 8% sevoflurane in 100% oxygen.

        -  After securing an IV line with cannula, all patients will receive fentanyl 1mcg /kg.

        -  Laryngeal mask air way of proper size will be inserted under adequate depth of
           anaesthesia.

        -  Anaesthesia will be maintained with sevoflurane with concentration maintaining adequate
           depth of anaesthesia.

        -  At the end of procedure and before application of stitches, bupivacaine 0.25% will be
           infiltrated in the skin and subcutaneous layer in group L, and caudal block will be
           performed in group C; at the end of surgery inhalational anaesthetics will be stopped;
           laryngeal mask will be removed when patient is fully conscious.

        -  Postoperative pain will be assessed using the Faces Legs Activity Cry Consolability tool
           (FLACC, 0- 10) at 15 min, 1, and 3 h after operation.(11) Table (I): FLACC scale
           (Behavioral observation pain rating scale) Categories Scoring 0 1 2 Face No particular
           expression or smile; disinterested Occasional grimace or frown, withdrawn Frequent to
           constant frown, clenched jaw, quivering chin Legs No position or relaxed Uneasy,
           restless, tense Kicking, or legs drawn up Activity Lying quietly, normal position, moves
           easily Squirming, shifting back and forth, tense Arched, rigid, or jerking Cry No crying
           (awake or asleep) Moans or whimpers, occasional complaint Crying steadily, screams or
           sobs, frequent complaints Consolability Content, relaxed Reassured by occasional
           touching, hugging, or talking to. Distractible Difficult to console or comfort Each of
           the five categories (F) face; (L) legs; (A) Activity; (C) Cry; (C) Consolability is
           scored from 0-2, which results in a total score between 0 and 10.

        -  A child with a score of more than 4 on FLACC will receive intravenous acetaminophen
           15mg/kg.

        -  The incision will then be monitored for signs of infection (Redness, Hotness, Swelling,
           Discharge, or Separation/Breakdown of deep tissues).

        -  Data regarding the incision will be obtained on day 7 postoperative or with sutures
           removal or any time before this if he/she develops any of wound inflammation signs
           earlier.

      D) Measurements:

        -  Postoperative vital signs/hour for 4 hours.

        -  Faces Legs Activity Cry Consolability tool (FLACC, 0- 10) at 15 min, 1, and 3 h after
           operation.(11)

        -  Timing of first postoperative complaint of pain, first requirement for postoperative
           analgesia and total consumption of analgesia

        -  Laboratory measurements: white blood cells count at day 0 and day 7 postoperative.

        -  Culture: with first dressing change at day 7 postoperative from the wounds with
           discharge (suspected infected wounds).

        -  Wound infection and healing scale: using Southampton scoring system,(12) which
           classifies wounds according to healing into 6 grades (0, I, II, III, IV, V).

      Table (II): Southampton wound scoring system Southampton wound scoring system Grade
      Appearance 0 Normal healing I Normal healing with bruising or mild erythema A Some bruising B
      Considerable bruising C Mild erythema II Erythema +other signs of inflammation A At one point
      B Around the sutures C Along the wound D Around the wound III Clear or heamoserous discharge
      A At one pint only (<2cm) B Along the wound (>2cm) C Large volume D Prolonged (3days) Major
      complication IV pus A At one point only (<2cm) B Along the wound (>2cm) V: deep or severe
      wound infection with or without tissue break down; hematoma requiring aspiration.

      ETHICS OF RESEARCH

      Research on human or human products:

      Prospective study: Informed consent will be taken from patients. In case of incompetent
      patients the informed consent will be taken from the guardians.
    

Intervention name(s): Caudal block; Wound infiltration; Bupivacaine
Intervention type(s): Procedure; Procedure; Drug
Intervention description(s): Caudal block/bupivacaine 0.25%; Local anesthetic wound infiltration/bupivacaine 0.25%; bupivacaine
Intervention MeSH terms: Bupivacaine
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: The patients will be classified randomly into two groups using closed envelope technique, 25 patients each:
Group L: 25 patients will receive 1mg/kg bupivacaine 0.25% (diluted as 1ml bupivacaine + 1ml normal saline) by local infiltration in the wound before closure of the skin and subcutaneous.
Group C: 25 patients will receive caudal block with 1mg/kg bupivacaine 0.25%.
Masking: Triple (Participant, Care Provider, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Local anesthetic; Hernioraphy; Wound healing