الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 101 |  |  |
| | | from | 101 | | |
Abstract
Uncontrolled postoperative pain may produce a range of detrimental acute and chronic effects. Attenuation of perioperative pathophysiology that occurs during surgery through reduction of nociceptive input into the CNS and optimization of perioperative analgesia may decrease complication and facilitate the patient’s recovery during the immediate postoperative period and after discharge from the hospital.
The pain following thoracotomy surgeries is particularly severe as the surgery involves muscle-dividing incision of the chest wall, which moves during respiration. Normal and deep breathing results in stretching of the skin incision. This stretching during deep inspiration and active exhalation results in severe pain and it results in reduced lung volume and capacities.
Acute post thoracotomy pain could be defined as severe acute pain after thoracotomy due to retraction, resection, or fracture of ribs, dislocation of costovertebral joints, injury of intercostal nerves, and further irritation of the pleura by chest tubes. While chronic post-thoracotomy pain is defined as pain that recurs or persists along a thoracotomy incision at least two month following the surgical procedure. In general, it is burning and stabbing pain with dysesthesia and thus shares many features of neuropathic pain.
The use of epidural analgesia for the management of postoperative pain has evolved as a critical component of multimodal approach to achieve the goal of adequate analgesia with improved outcome. Epidural analgesia offers superior postoperative pain relief compared with systemic opioids or patient controlled analgesia (PCA). In a comparative study of thoracic epidural analgesia versus systemic, there were well-demonstrated improvements in analgesia and quality of life in patients receiving epidurals.
Efforts to incorporate ultrasound into anesthetic practice are fundamentally rooted in the goals of improving patient safety and interventional anesthesia efficacy. Although most anesthesiologists are well aware of the challenges of vascular access and regional anesthesia (for both success and potential complications), the introduction of this technology presents novel challenges of acquiring new knowledge and skill sets to achieve these goals. As with acquiring any new skill, there will be initial challenges for both the novice and experienced anesthesiologist. from correlating anatomy with sonoanatomy, and visualizing needles and fluid dynamics in real-time below the skin surface, ultrasound provides opportunities and unique challenges for vascular access and regional anesthesia.
Patients and methods
The study was carried out on 30 adult patients of either sex with body mass index BMI below 25 kg/m2 admitted to “Alexandria Main University hospital”. All of them were evaluated as American Society of Anesthesiologists ASA physical status class I and II scheduled for elective thoracic surgery under general anesthesia where thoracic epidural analgesia as a part of the anesthetic plan. The sample size was statistically approved by the biostatistics department of High Institute of Public Health Alexandria University. Exclusion criteria were contraindications to epidural anesthesia such as: severe aortic valve stenosis, active neurologic disease, preoperative impaired coagulation status, infection at the site of insertion, increased intracranial pressure, patient refusal, pregnant females and allergy to lidocaine or bubivacaine. Patients were randomized by closed envelope method into 2 equal groups (n=15):
group I: in which ultrasound machine was the guiding tool for the process of thoracic epidural catheter insertion as regards interspinous space identification and needle direction.
group II: in which thoracic epidural catheter was inserted by the conventional technique; i.e. needle insertion was based on palpating the interspinous space by the anesthesiologist.
Preoperative evaluation of the patients was carried out through proper history taking,clinical examination and all needed laboratory investigations.
All patients were informed about the technique applied and any possible complications and a written consent was taken. Patients were premedicated by Midazolam 0.07 mg/kg i.m half an hour before surgery. On arrival to the operation room a multi-channel monitor (Trakmon kontron limited - England) was attached to the patient to display the standard monitorings and an18 G cannula was inserted. All patients will be seated upright and given leg and arm support with the neck flexed.
In group I patients an ultrasound assessment was carried out using a linear probe (6-15 MHz) of SONOSITE M-TURBO ultrasound machine and intervertebral level was identified based on the ‘‘counting-up’’ method from the sacrum in the midline plane with the probe placed vertically, vertebral bodies appeared as finger like projections and interspinous spaces in-between, the desired level was marked on the patient skin . Under complete aseptic technique skin was disinfected using povidone iodine 10% solution and the probe was lubricated with sterile gel and covered with a sterile transparent camera cover (that is used with laparoscopy cameras) or sterile glove. After local infiltration of the skin on the marked area with 4 ml of 2% lidocaine an 18G Tuohy needle was advanced under ultrasound guidance with an assistant radiologist holding the probe vertically in the paramedian plane to visualize the echogenic ligamentum flavum (LF). The echo-dense LF appeared as a bright echo at the base of the laminae as the epidural space cannot be visualized separately , we considered the skin-to-epidural depth by measuring depth from skin to LF using electronic caliber tool in US machine, needle was advanced under ultrasound guidance in the identified space with loss of resistance(LOR) to saline, after successful LOR catheter was inserted and after negative aspiration for blood or cerebrospinal fluid a test dose of 3 ml of 2% lidocaine with 1:200,000 adrenaline was administrated through the epidural catheter to ensure correct placement of the catheter and exclude intrathecal or intravascular injection then the catheter will be fixed to the patient’s back using adhesive tape.
In group II patients an imaginary line joinig the scapular apices was considered the anatomical landmark for T7 spine palpated in the midline, the desired interspace was chosen by counting up or down from T7 level. Under complete aseptic technique using povidone iodine 10% solution on the patient’s back, local skin infiltration in the selected space was done as in group I then the 18G Touhy needle was advanced blindly with LOR to saline technique, after successful LOR the catheter was inserted and after negative aspiration for blood and CSF the same test dose as in group I was administered then the catheter was fixed using adhesive tape
In both I and II groups: After successful catheter placement the patients were positioned supine and induction of general anaesthesia was performed with fentanyl 1microgram/kg, xylocaine 60mg, propofol 2mg/kg , and rocuronium 0.6 mg /kg with 1.2% isoflourane in 100% oxygen then endotracheal intubation was performed, and anesthesia was maintained by 1.2% isoflourane and rocuronium 0.1 mg/kg as top up doses; five minutes prior to surgical skin incision epidural activation will be carried out using 6 ml of 0.25 % bupivacaine and 50 micrograms fentanyl followed by epidural infusion of 0.125 bubivacaine in 4 ml per hour rate as a method of intra and postoperative pain relief , the catheter was removed in the surgical intensive care unit 24 hours postoperatively. In cases of failed epidural nalbuphine 0.15 mg/kg was administered intravenously as rescue analgesia intra and postoperatively.
Measurements
The following demographic data were measured; age (years), Sex, body weight (kg), height in meter and body mass index BMI. Hemodynamic parameters recorded were ; Heart rate (HR in beats per minute) ,non-invasive arterial blood pressure (mmHg), systolic arterial blood pressure (SBP) and diastolic arterial blood pressure (DBP) at the following periods:on patient arrival to the operating room (as a baseline ),after test dose delivery (to exclude intravascular injection),five and ten minutes after induction of general anesthesia,ten and twenty minutes after administration of first dose of epidural analgesia.Time taken from first puncture to successful LOR in minutes.The number of skin punctures till LOR. Number of needle redirections.Number of times in which the vertebra was hit by the Touhy needle. Skin to epidural space depth and length of the catheter inserted in centimeter, failure to obtain loss of resistance and technique failure (after 5 skin punctures in both groups). Intrathecal or intravascular injection after test dose delivery and possible complications such as dural puncture, hemorrhagic tap, accidental intravascular injection, epidural hematoma, spinal cord injury or postoperative back pain. Patient satisfaction was recorded after both catheter insertion and removal.
Results:
As regard demographic data: There were no significant differences between the two groups as regards age (P=0.494), sex (P = 0.456), weight (P = 0.726), height (P = 0.371) and body mass index (P = 0.799). A significant increase in insertion time was recorded in group I (P <0.001), the number of skin punctures till LOR was significantly lower in group I (P= 0.043), needle redirections was also lower in group I (P= 0.020), vertebrae were less hit by the needle in group I (P= 0.026), no significant difference as regards epidural space depth or catheter length. A case of epidural failure was recorded in group II and also an accidental hemorrhagic tap was recorded in the same group. Patient satisfaction both after catheter insertion and removal was higher at group I (P= 0.031) and (P= 0.002) respectively.