Faraj W. Abdallah

Transversus abdominis plane block: a systematic review.

Ultrasound guidance has led a surge of interest in transversus abdominis plane (TAP) block for postoperative analgesia following abdominal surgery. Despite or because of the numerous descriptive applications and techniques that have recently populated the literature, results of comparative studies for TAP block have been inconsistent. This systematic review pragmatically addresses many unanswered questions, specifically the following: what are the effects of surgical procedure, block dose, block technique, and block timing on TAP block analgesia? Eighteen intermediate- to good-quality randomized trials that included diverse surgical procedures were identified. Improved analgesia was noted in patients undergoing laparotomy for colorectal surgery, laparoscopic cholecystectomy, and open and laparoscopic appendectomy. There was a trend toward superior analgesic outcomes when 15 mL of local anesthetic or more was used per side compared with lesser volumes. All 5 trials investigating TAP block performed in the triangle of Petit and 7 of 12 trials performed along the midaxillary line demonstrated some analgesic advantages. Eight of 9 trials using preincisional TAP block and 4 of 9 with postincisional block revealed better analgesic outcomes. Although the majority of trials reviewed suggest superior early pain control, we were unable to definitively identify the surgical procedures, dosing, techniques, and timing that provide optimal analgesia following TAP block. This review suggests that our understanding of the TAP block and its role in contemporary practice remains limited.

The Analgesic Efficacy of Subarachnoid Morphine in Comparison with Ultrasound-Guided Transversus Abdominis Plane Block After Cesarean Delivery: A Randomized Controlled Trial

BACKGROUND: Ultrasound-guided transversus abdominis plane block is an effective method of providing pain relief after cesarean delivery. Neuraxial morphine is currently the “gold standard” treatment for pain after cesarean delivery. In this study we tested the hypothesis that subarachnoid morphine would provide more prolonged and superior analgesia than would transversus abdominis plane block in patients undergoing elective cesarean delivery. METHODS: In this prospective, double-blind study, 57 patients were randomly assigned to receive either subarachnoid morphine (group SAM; n = 28) or transversus abdominis plane block (group TAP; n = 29). Patients received bupivacaine spinal anesthesia combined with morphine 0.2 mg in group SAM and received saline in group TAP. At the end of surgery, bilateral transversus abdominis plane block was performed using saline in group SAM or using bupivacaine 0.375% plus epinephrine 5 &mgr;g/mL in group TAP with 20 mL on each side. Postoperative analgesia for the first 24 hours consisted of scheduled rectal diclofenac and IV paracetamol; breakthrough pain was treated with IV tramadol. For the next 24 hours, scheduled rectal diclofenac was given; oral paracetamol and IV tramadol were administered upon patient request. Patients were assessed postoperatively in the postanesthesia care unit (time 0 hours) and at 2, 4, 6, 12, 24, 36, and 48 hours. The primary outcome measure was the time to first analgesic request. RESULTS: Median (range) time to first analgesic request was longer in group SAM than in group TAP [8 (2–36) hours versus 4 (0.5 to 29) hours (P = 0.005)]. Median (range) number of tramadol doses received between 0 and 12 hours was 0 (0–1) in group SAM versus 0 (0–2) in group TAP (P = 0.03). Postoperative visceral pain scores at rest and on movement during first the 4 hours were lower in group SAM than in group TAP, but were not different at any other time points. The incidence of moderate to severe nausea was higher in group SAM than in group TAP [13/28 (46%) versus 5/29 (17%) (P = 0.02)]. More patients developed pruritus requiring treatment in group SAM than in group TAP [(11/28 (39%) versus none (0%) (P < 0.001)]. CONCLUSION: As part of a multimodal analgesic regimen, subarachnoid morphine provided superior analgesia when compared with ultrasound-guided transversus abdominis plane block after cesarean delivery, yet at the cost of increased side effects.

Is sciatic nerve block advantageous when combined with femoral nerve block for postoperative analgesia following total knee arthroplasty? A systematic review.

Sciatic nerve block (SNB) is commonly performed in combination with femoral nerve block (FNB) for postoperative analgesia following total knee arthroplasty (TKA). This systematic review examines the effects of adding SNB to FNB for TKA compared with FNB alone on acute pain and related outcomes. Four intermediate-quality randomized and 3 observational trials, including a total of 391 patients, were identified. Three of 4 trials investigating the addition of single-shot SNB and 2 of 3 trials investigating continuous SNB reported improved early analgesia at rest and reduced early opioid consumption. Only 2 trials specifically assessed posterior knee pain. We were unable to uncover any clinically important analgesic advantages for SNB beyond 24 hours postoperatively. At present, there is inconclusive evidence in the literature to define the effect of adding SNB to FNB on acute pain and related outcomes compared with FNB alone for TKA.

Ultrasound-guided Popliteal Block Through a Common Paraneural Sheath Versus Conventional Injection: A Prospective, Randomized, Double-blind Study

Background and Objectives The macroscopic anatomy of a common paraneural sheath that surrounds the sciatic nerve in the popliteal fossa has been studied recently in a human cadaveric study. It has been suggested that an injection through this sheath could be an ideal location for local anesthetic administration for popliteal block. The aim of the present study was to evaluate the hypothesis that popliteal sciatic nerve blockade through a common paraneural sheath results in shorter onset time when compared with conventional postbifurcation injection external to the paraneural tissue. To illustrate the microscopic anatomy of the paraneural tissues, we performed histological examinations of a human leg specimen. Methods Following institutional review board approval and written informed consent, 89 patients undergoing an ultrasound-guided popliteal block for foot or ankle surgery were included in the study. They were prospectively randomized to receive a single injection of local anesthetic at the site of bifurcation through a common paraneural sheath (group 1) or 2 separate circumferential injections of the tibial and common peroneal nerves distally to sciatic nerve bifurcation (group 2). Results Patients in group 1 had a 30% shorter onset time of both sensory and motor block. This was associated with a more extensive proximal and distal longitudinal spread of local anesthetic in this group. Nerve diameter and cross-sectional area remained unchanged in both groups after injection, which is consistent with extraneural injection. A greater proportion of patients in group 1 required a single needle pass for block performance. Discussion An ultrasound-guided popliteal sciatic nerve block through a common paraneural sheath at the site of sciatic nerve bifurcation is a simple, safe, and highly effective block technique. It results in consistently short onset time, while respecting the integrity of the epineurium and intraneural structures.

Intravenous dexamethasone and perineural dexamethasone similarly prolong the duration of analgesia after supraclavicular brachial plexus block: a randomized, triple-arm, double-blind, placebo-controlled trial.

Background and Objectives Perineural dexamethasone prolongs the duration of single-injection peripheral nerve block when added to the local anesthetic solution. Postulated systemic mechanisms of action along with theoretical safety concerns have prompted the investigation of intravenous dexamethasone as an alternative, with decidedly mixed results. We aimed to confirm that addition of intravenous dexamethasone will prolong the duration of analgesia after single-injection supraclavicular block compared with conventional long-acting local anesthetic alone or in combination with perineural dexamethasone for ambulatory upper extremity surgery. Methods Seventy-five patients were randomized to receive supraclavicular block using 30-mL bupivacaine 0.5% alone (Control), with concomitant intravenous dexamethasone 8 mg (DexIV), or with perineural dexamethasone 8 mg (DexP). Duration of analgesia was designated as the primary outcome. To test our hypothesis, the superiority of DexIV was first compared with Control and then with DexP. Motor block duration, pain scores, opioid consumption, opioid-related side effects, patient satisfaction, and block-related complications were also analyzed. Results Twenty-five patients per group were analyzed. The duration of analgesia (mean [95% confidence interval]) was prolonged in the DexIV group (25 hours [17.6–23.6]) compared with Control (13.2 hours [11.5–15.0]; P < 0.001) but similar to the DexP group (25 hours [19.5–27.4]; P = 1). The DexIV group experienced longer motor block (30.1 hours) compared with DexP (25.5 hours) and Control (19.7 hours) groups. Both DexIV and DexP had reduced pain scores, reduced postoperative opioid consumption, and improved satisfaction compared with Control. Conclusions In a single-injection supraclavicular block with long-acting local anesthetic, the effectiveness of intravenous dexamethasone in prolonging the duration of analgesia seems similar to perineural dexamethasone.

Ultrasound-guided Multilevel Paravertebral Blocks and Total Intravenous Anesthesia Improve the Quality of Recovery after Ambulatory Breast Tumor Resection

Background:Regional anesthesia improves postoperative analgesia and enhances quality of recovery (QoR) after ambulatory surgery. This randomized, double-blinded, parallel-group, placebo-controlled trial examines the effects of multilevel ultrasound-guided paravertebral blocks (PVBs) and total intravenous anesthesia on QoR after ambulatory breast tumor resection. Methods:Sixty-six women were randomized to standardized general anesthesia (control group) or PVBs and propofol-based total intravenous anesthesia (PVB group). The PVB group received T1–T5 PVBs with 5 ml of 0.5% ropivacaine per level, whereas the control group received sham subcutaneous injections. Postoperative QoR was designated as the primary outcome. The 29-item ambulatory QoR tool was administered in the preadmission clinic, before discharge, and on postoperative days 2, 4, and 7. Secondary outcomes included block success, pain scores, intra- and postoperative morphine consumption, time to rescue analgesia, incidence of nausea and vomiting, and hospital discharge time. Results:Data from sixty-four patients were analyzed. The PVB group had higher QoR scores than control group upon discharge (146 vs. 131; P < 0.0001) and on postoperative day 2 (145 vs. 135; P = 0.013); improvements beyond postoperative day 2 lacked statistical significance. None of the PVB group patients required conversion to inhalation gas–based general anesthesia or experienced block-related complications. PVB group patients had improved pain scores on postanesthesia care unit admission and discharge, hospital discharge, and postoperative day 2; their intraoperative morphine consumption, incidence of nausea and vomiting, and discharge time were also reduced. Conclusion:Combining multilevel PVBs with total intravenous anesthesia provides reliable anesthesia, improves postoperative analgesia, enhances QoR, and expedites discharge compared with inhalational gas- and opioid-based general anesthesia for ambulatory breast tumor resection.

A randomized trial comparing colloid preload to coload during spinal anesthesia for elective cesarean delivery.

BACKGROUND: Hypotension after spinal anesthesia for cesarean delivery is common. Previous studies have demonstrated that a crystalloid fluid “coload” (rapid administration of a fluid bolus starting at the time of intrathecal injection) is superior to the conventional crystalloid preload (fluid administered before the intrathecal injection) for preventing hypotension. Colloid preload provides a sustained increase in central blood volume. We hypothesized that, in contrast to crystalloid, a colloid preload may be more effective than colloid coload for reducing the incidence of spinal anesthesia-induced hypotension. METHODS: In this double-blind study, 178 patients were randomly assigned to receive a preload of 500 mL of hydroxyethyl starch over a period of 15–20 min before initiation of spinal anesthesia (n = 90) or an identical fluid bolus of hydroxyethyl starch starting at the time of identification of cerebrospinal fluid (n = 88). Vasopressors (ephedrine or phenylephrine) were administered if systolic arterial blood pressure decreased less than 80% of the baseline pressure and <100 mm Hg, or with smaller decreases in blood pressure if accompanied by nausea, vomiting, or dizziness. The primary outcome was the incidence of hypotension (defined as the administration of at least one dose of vasopressor). RESULTS: There was no significant difference between the groups in the incidence of hypotension (68% in preload group and 75% in coload group, 95% confidence interval of difference −6%–20%; P = 0.28), doses of ephedrine and phenylephrine, and number of vasopressor unit doses. The incidence of severe hypotension (systolic blood pressure <80 mm Hg) was 16% in the preload group and 22% in the coload group (P = 0.30). There were no differences in the incidence of nausea and/or vomiting, or neonatal outcome between the groups. CONCLUSION: There was no difference in the incidence of hypotension in women who received colloid administration before the initiation of spinal anesthesia compared with at the time of initiation of anesthesia. Both modalities are inefficient as single interventions to prevent hypotension.

Femoral vein cannulation performed by residents: a comparison between ultrasound-guided and landmark technique in infants and children undergoing cardiac surgery.

BACKGROUND: Percutaneous cannulation of the femoral vein, in the pediatric age group, can be technically challenging, especially when performed by residents in training. We examined whether the use of real-time ultrasound guidance is superior to a landmark technique for femoral vein catheterization in children undergoing heart surgery. METHODS: Patients were prospectively randomized into 2 groups. In group LM, the femoral vein was cannulated using the traditional method of palpation of arterial pulse. In group US, cannulation was guided by real-time scanning with an ultrasound probe. The time to complete cannulation (primary outcome), success rate, number of needle passes, number of successful cannulations on first needle pass, and incidence of complications were compared between the 2 groups. RESULTS: Forty-eight pediatric patients were studied. The time to complete cannulation was significantly shorter (155 [46–690] vs 370 [45–1620] seconds; P = 0.02) in group US versus group LM. The success rate was similar in both groups (95.8%). The number of needle passes was smaller (1 [1–8] vs 3 [1–21]; P = 0.001) and the number of successful cannulations on first needle pass higher (18 vs 6; P = 0.001) in group US compared with group LM. The incidence of femoral artery puncture was comparable between the 2 groups. CONCLUSIONS: Ultrasound-guided cannulation of the femoral vein, in pediatric patients, when performed by senior anesthesia residents, is superior to the landmark technique in terms of speed and number of needle passes, with remarkable improvement in first attempt success.

Effect of labor analgesia on labor outcome

Purpose of review Labor is among the most painful experiences that humans encounter. Neuraxial analgesia is the most effective means of treating this pain. In this review, we discussed the effect of neuraxial analgesia on the progress of labor when compared with parenteral opioids. We then compared initiation of analgesia with a combined spinal–epidural technique (CSE) to conventional epidural analgesia. Finally we discussed the impact of neuraxial analgesia, given early in labor, compared with later administration. Recent findings Compared with parenteral opioids, neuraxial analgesia does not increase the incidence of cesarean section, although it is associated with a longer (∼16 min) second stage of labor. The incidence of operative vaginal delivery is higher in the epidural group but this may be due to indirect reasons such as changes in physician behavior. There was no difference in labor outcome when CSE was compared with low-concentration epidural analgesia, but higher concentrations may prolong labor. Early administration of neuraxial analgesia does not increase the incidence of operative delivery or prolong labor. Summary Neuraxial analgesia does not interfere with the progress or outcome of labor. There is no need to withhold neuraxial analgesia until the active stage of labor.

The analgesic effects of proximal, distal, or no sciatic nerve block on posterior knee pain after total knee arthroplasty: a double-blind placebo-controlled randomized trial.

Background:The analgesic efficacy of sciatic nerve block (SNB) after total knee arthroplasty (TKA) is unclear. Proximal and distal SNB are each reported to provide posterior knee analgesia, whereas others suggest that posterior knee pain is not important after TKA. This prospective, randomized, double-blind, parallel-arm, placebo-controlled trial examined whether proximal or distal SNB provides superior analgesia in the posterior knee compared with no SNB after TKA. Methods:Sixty patients undergoing TKA were randomized to single-shot SNB using either the infragluteal (Proximal group) or popliteal (Distal group) technique, or no SNB (Placebo group). All patients received spinal anesthesia and continuous-femoral nerve blockade. A blinded observer assessed posterior and anterior knee pain at 2, 4, 6, 8, 12, and 24 h postoperatively. The primary outcome was moderate-to-severe posterior knee pain at 4 h postoperatively; secondary outcomes included SNB procedural time, needle passes, and discomfort. Results:Fifty-three patients were analyzed. The proportion of patients (Proximal:Distal:Placebo) who experienced moderate-to-severe posterior knee pain was 18%:22%:89% (P < 0.00001) at 2 h, 24%:28%:72% (P < 0.01) at 4 h, and 12%:17%:78% (P = 0.00003) at 6 h postoperatively. For the anterior knee, the proportion of patients reporting moderate-to-severe pain was 6%:11%:44% (P = 0.02) at 2 h, 6%:6%:39% (P = 0.012) at 4 h, and 12%:6%:44% (P = 0.017) at 6 h postoperatively. Moderate-to-severe pain did not differ between groups beyond 6 h. Both proximal and distal SNB reduced rest pain in the posterior and anterior knee up to 8 h postoperatively compared with no SNB. The popliteal technique required shorter procedural time, fewer needle passes, and produced less discomfort. Conclusion:Proximal and distal SNB each reduce posterior and anterior knee pain after TKA compared with no SNB.