Clemens M. Ortner

Effect of Transversus Abdominis Plane Block With and Without Clonidine on Post–cesarean Delivery Wound Hyperalgesia and Pain

Background and Objectives The transversus abdominis plane (TAP) block is an established technique to manage post–cesarean delivery pain. Transversus abdominis plane blocks with a local anesthetic only offer no analgesic benefits compared with intrathecal morphine. Adjuvants to extend TAP block duration and possibly reduce wound hyperalgesia, known to be a risk factor for chronic pain, have not been studied. We hypothesized that a TAP block with clonidine will affect postsurgical wound hyperalgesia and improve pain outcomes. Methods Ninety women were randomly assigned to receive 1 of 3 TAP blocks after cesarean delivery: saline (placebo), bupivacaine (BupTAP), or bupivacaine + clonidine (CloTAP). The primary outcome was wound hyperalgesia index at 48 hours. Secondary outcomes included pain scores, analgesic consumption, and pain descriptors up to 12 months. Results Wound hyperalgesia index at 48 hours (median [25th–75th percentiles]) was 1.07 (0.48–3.26) in the placebo group, 1.27 (0.59–2.95) in the BupTAP group, and 0.74 (0.09–2.25) in the CloTAP group (P = 0.48). Morphine request in the postanesthesia care unit was significantly higher in the placebo group compared with the other TAP groups (P = 0.01). Postoperative pain scores and requests for breakthrough medication at 48 hours (30% in the placebo group, 24% in the BupTAP group, and 12% in the CloTAP group, P = 0.25) or chronic pain descriptors reported up to 12 months did not differ significantly among groups. Conclusions Adding clonidine to a TAP block with bupivacaine did not affect wound hyperalgesia index and it did not improve short-term or long-term pain scores in women undergoing elective cesarean delivery. Further studies are warranted to determine the benefits of antihyperalgesic adjuvants in TAP solutions for specific individuals at risk for chronic pain.

Chronic pain after childbirth

With over four million deliveries annually in the United States alone and a constant increase in cesarean delivery rate, childbirth is likely to have a huge impact on the occurrence of acute and possibly chronic postpartum pain. Recent awareness that chronic pain may occur after childbirth has prompted clinicians and researchers to investigate this topic. Current evidence points towards a relatively low incidence of chronic pain after cesarean delivery, with rates ranging between 1% and 18%. To provide a potential mechanistic explanation for the relatively low occurrence of chronic pain after cesarean delivery compared with that after other types of surgery, it has been proposed that endogenous secretion of oxytocin may confer specific protection. Clinical interventions to reduce the incidence and severity of chronic post-surgical pain have not been consistently effective. Likely explanations are that the drugs that have been investigated were truly ineffective or that the effect was too modest because with a low incidence of chronic pain, studies were likely to be underpowered and failed to demonstrate an effect. In addition, since not all women require preventive therapies, preoperative testing that may identify women vulnerable to pain may be highly beneficial. Further research is needed to identify valid models that predict persistent pain to allow targeted interventions to women most likely to benefit from more tailored anti-hyperalgesic therapies.

Transversus abdominis plane catheters for post-cesarean delivery analgesia: a series of five cases.

We present five cases of women who received ultrasound-guided transversus abdominis plane catheters for post-cesarean delivery analgesia. Pain relief was maintained with repeated boluses of local anesthetic combined with oral acetaminophen and ibuprofen unless contraindicated. We conclude that repeated dosing through transversus abdominis plane catheters may be offered to women as an alternative or adjuvant to intrathecal morphine. Larger studies to evaluate the safety and further refinements of this novel procedure are warranted.

Preoperative scar hyperalgesia is associated with post-operative pain in women undergoing a repeat Caesarean delivery.

Over 1.4 million Caesarean deliveries are performed annually in the United States, out of which 30% are elective repeat procedures. Post‐operative hyperalgesia is associated with an increased risk for persistent post‐surgical pain; however, there are no data on whether residual scar hyperalgesia (SHA) from a previous Caesarean delivery (CD) persists until the next delivery. We hypothesized that residual SHA may be present in a substantial proportion of women and is associated with increased post‐operative pain.

Dose response of tramadol and its combination with paracetamol in UVB induced hyperalgesia

Combining tramadol with paracetamol is an established analgesic treatment strategy. However, dosing and differential effects on peripheral and central hyperalgesia are still to be determined. After Ethics Committee approval, 32 volunteers have been included in this 2 phased, double blinded, placebo controlled, cross‐over study. A defined small skin area was irradiated with a UVB source inducing hyperalgesia. Twenty‐four hours after irradiation, heat pain‐, cold pain threshold (HPPT, CPPT), mechanical pain sensitivity to pin prick (MPS) in the area of pin prick hyperalgesia (AsH) and MPS in the sunburn were determined. In phase I, measurements have been repeated 30 min after receiving cumulative 0.3, 0.6 and 1 mg/kg of intravenous (i.v.) tramadol or active placebo. Only at 1 mg/kg tramadol and solely for MPS in the sunburn a reduction to placebo could be demonstrated (p = 0.024). Accordingly in phase II, the trial has been repeated using 1 mg/kg tramadol and paracetamol or placebo in a cumulative i.v. dose of 330, 660 and 990 mg. Now the addition of 330 mg paracetamol to tramadol reduced thermal hyperalgesia by 1.15 °C (CI 0.55; 1.76). This effect, however, did not increase with higher doses. Tramadol showed week anti‐hyperalgesia reducing CPPT, MPS and AsH compared to baseline measurements (p < 0.05). Paracetamol also reduced secondary hyperalgesia, but no combination effect with tramadol could be shown. We conclude, in inflammatory hyperalgesia tramadol alone exerts only weak anti‐hyperalgesia. Even adding a small dose paracetamol enhances thermal anti‐hyperalgesia.

The Short-FormMcGill Pain Questionnaire-Revised to Evaluate Persistent Pain and Surgery-Related Symptoms in Healthy Women Undergoing a Planned Cesarean Delivery

Background and Objectives The incidence of chronic pain after cesarean delivery (CD) has been estimated to range between 0.3% and 18%. This wide range may be explained by differing study methodologies. Furthermore, a comprehensive characterization of pain quality is lacking. The aim of this study was to evaluate persistent pain in a healthy obstetric population undergoing planned CD and to provide a comprehensive description of pain quality. Methods Three hundred eighty-one women with no pain history undergoing CD were included in this prospective, observational cohort study. Spinal anesthesia was standardized, and postoperative pain was recorded at 24 hours. In each woman, pain was assessed at 8 weeks, and 6 and 12 months using questionnaires of pain intensity and interference. Pain quality was assessed using the Short-Form McGill Pain Questionnaire–Revised. Results The incidence of persistent pain at 8 weeks was 11% (95% confidence interval, 8%–14%), with pain reported as being mild and interfering with common daily activities by 32% of women. At 6 and 12 months, the incidence was 3% (95% confidence interval, 2%–6%) and 0.6% (95% confidence interval, 0%–2%) respectively, with pain rarely interfering with daily activities. However, 22% of women described other surgery-related symptoms at 12 months. Conclusions The incidence of chronic pain at 12 months after planned CD is low (0.6%) and if present symptoms are mostly mild and not interfering with common daily activities. Using Short-Form McGill Pain Questionnaire–Revised, this study provides a comprehensive evaluation of pain quality that can be used as a basis in future post-CD pain trials.

On the ropivacaine‐reducing effect of low‐dose sufentanil in intrathecal labor analgesia

Background: Combining ropivacaine with sufentanil for intrathecal (i.t.) analgesia in labor is well recognized, but information on dosing is limited. This study aimed to determine the ED 50 of i.t. ropivacaine and to assess the effect of adding defined low doses of sufentanil.

Evaluation of performance of two different chest tubes with either a sharp or a blunt tip for thoracostomy in 100 human cadavers

BackgroundEmergent placement of a chest tube is a potentially life-saving procedure, but rate of misplacement and organ injury is up to 30%. In principle, chest tube insertion can be performed by using Trocar or Non-trocar techniques. If using trocar technique, two different chest tubes (equipped with sharp or blunt tip) are currently commercially available. This study was performed to detect any difference with respect to time until tube insertion, to success and to misplacement rate.MethodsTwenty emergency physicians performed five tube thoracostomies using both blunt and sharp tipped tube kits in 100 fresh human cadavers (100 thoracostomies with each kit). Time until tube insertion served as primary outcome. Complications and success rate were examined by pathological dissection and served as further outcomes parameters.ResultsDifference in mean time until tube insertion (63s vs. 59s) was statistically not significant. In both groups, time for insertion decreased from the 1st to the 5th attempt and showed dependency on the cadavers BMI and on the individual physician. Success rate differed between both groups (92% using blunt vs. 86% using sharp tipped kits) and injuries and misplacements occurred significantly more frequently using chest tubes with sharp tips (p = 0.04).ConclusionData suggest that chest drain insertion with trocars is associated with a 6-14% operator-related complication rate. No difference in average time could be found. However, misplacements and organ injuries occurred more frequently using sharp tips. Consequently, if using a trocar technique, the use of blunt tipped kits is recommended.

Challenges in interpreting joined allelic combinations of OPRM1 and COMT genes.

procedures likely to result in the best outcomes. This was highlighted by the lack of agreement among our surveyed anesthesiology preoperative center directors as to the necessity for most suggested tests. Without such knowledge, Lean Six Sigma would not apply. We think it unlikely that change will come without focused leadership from national organizations encouraging large observational studies linking data from preanesthesia evaluation to patient outcomes. Such studies were recently recommended by Dr. Kevin Tremper in the 49th annual Rovenstine lecture.

Osteogenesis imperfecta: cesarean deliveries in identical twins

Osteogenesis imperfecta is a congenital disorder resulting in multiple fractures and extremely short stature, usually necessitating cesarean delivery. Identical twins with severe osteogenesis imperfecta each of whom underwent a cesarean delivery with different anesthetic modalities are presented. A review of the literature and anesthetic options for cesarean delivery and postoperative analgesia for women with osteogenesis imperfecta are discussed.