Comparison of Postoperative Opioid Consumption of Paravertebral Block and Erector Spinae Plane Block After Thoracotomy: A Randomized Controlled Trial.

Background Thoracotomy is associated with severe postoperative pain. Pain developing after thoracotomy causes lung infections, inability to expel secretions, and atelectasis as a result of deep breathing. Effective management of acute pain after thoracotomy may prevent these complications. A multimodal approach to analgesia is widely employed by thoracic anesthetists using a combination of regional anesthetic blockade and systemic analgesia, with both non-opioid and opioid medications and local anesthesia blockade. Nowadays, regional anesthesia techniques such as thoracic epidural paravertebral block (PVB), erector spinae plane block (ESPB), and serratus plane block are frequently used to prevent pain after thoracotomy. In this study, we compared paravertebral block with erector spinae block for pain relief after thoracotomy. Our primary aim was to determine whether there was a difference between postoperative opioid consumption and pain scores. We also compared the two regional anesthesia techniques in terms of intraoperative hemodynamic data and postoperative complications. Methodology Patients aged between 18 and 75 years with an American Society of Anesthesiology (ASA) physical status I-III and scheduled for elective thoracotomy were included in the study. Using www.randomizer.org, patients were divided into two different groups, namely, ESPB and PVB. All patients were provided with a patient-controlled analgesia device preloaded with morphine. Postoperative 24-hour morphine consumptions were recorded. Results Data from 45 patients were used in the final analyses. Morphine consumption was higher in the ESPB group than in the PVB group at 24 hours postoperatively (19.2 ± 4.26 mg and 16.2 ± 2.64 mg, respectively; p < 0.05). There was no significant difference in numerical rating scale scores both at rest and with coughing (p > 0.05). Intraoperative heart rates were similar between groups. However, mean intraoperative blood pressure was significantly lower in the PVB group at 30 minutes (p < 0.05). Nausea and vomiting were observed in two patients in the ESPB group and one patient in the PVB group. The complication of nausea and vomiting was not statistically significant between the two groups (p > 0.05). Catastrophic complications such as hematoma, pneumothorax, and local anesthetic systemic toxicity were not observed in either group. Conclusions We found that patients who underwent PVB consumed less morphine postoperatively than patients who underwent ESPB. However, we did not observe any difference in pain scores between both groups. We think that ESPB can be considered a reliable method in thoracotomy surgery due to its ease of application and the fact that the place where the block is technically performed is farther from the central structures compared to PVB. In light of the results of our study, ESPB can be used as an alternative to PVB, which has been proven as postoperative analgesia in thoracic surgery.

Modified pectoral nerve block versus bi-level erector spinae plane block for postoperative analgesia after radical mastectomy surgery: a prospective, randomized, controlled trial.

BACKGROUND: Regional anesthesia techniques constitute an important part of successful analgesia strategies in the perioperative care of patients undergoing breast surgery. The advent of ultrasound-guided regional anesthesia has led to the development of fascial plane blocks. The large array of blocks available for postoperative analgesia in breast surgery has increased the accessibility of regional anesthesia but has also created a dilemma of choice. This study compared the analgesic efficacy of the ultrasound-guided modified pectoral nerve (PECS) block and erector spinae plane block (ESPB) in patients undergoing radical mastectomy. METHODS: Seventy women were enrolled in this prospective, double-blind, randomized control trial. After exclusion, 67 female patients who underwent radical mastectomy were finally analyzed. Ultrasound-guided PECS blocks and ESPBs were performed with 30 ml 0.25% bupivacaine. Postoperative morphine and pain scores were compared between the groups. RESULTS: Postoperative total morphine consumption in the first 24 h was significantly higher in the PECS group (P < 0.001). The ESPB group exhibited significantly reduced morphine consumption at all postoperative time points. Numeric rating scale scores were lower in the ESPB group at 6, 12, and 24 h postoperatively at rest and when coughing. CONCLUSIONS: Ultrasound-guided bi-level ESPBs provided better postoperative analgesia than PECS blocks after radical mastectomy surgery.

Bilateral versus unilateral erector spinae plane block for postoperative analgesia in laparoscopic cholecystectomy: a randomized controlled study

Abstract Introduction Laparoscopic cholecystectomy (LC) is the common surgical intervention for benign biliary diseases. Postoperative pain after LC remains as an important problem, with two components: somatic and visceral. Trocar entry incisions lead to somatic pain, while peritoneal distension with diaphragm irritation leads to visceral pain. Following its description by Forero et al., the erector spinae plane (ESP) block acquired considerable popularity among clinicians. This led to the use of ESP block for postoperative pain management for various operations. Materials and methods This study was conducted between January and June 2019. Patients aged between 18 and 65 years with an American Society of Anesthesiologists (ASA) physical status I-II, scheduled for elective laparoscopic cholecystectomy were included in the study. All the patients received bilateral or unilateral ESP block at the T8 level preoperatively according to their groups. Results There was no significant difference between the groups in terms NRS scores either at rest or while coughing at any time interval except for postoperative 6th hour (p = 0.023). Morphine consumption was similar between the groups but was significantly lower in group B at 12 and 24 hours (p = 0.044 and p = 0.022, respectively). Twelve patients in group A and three patients in group B had shoulder pain and this difference was statistically significant (p = 0.011). Discussion In conclusion, bilateral ESP block provided more effective analgesia than unilateral ESP block in patients undergoing elective LC. Bilateral ESP block reduced the amount of opioid consumption and the incidence of postoperative shoulder pain.

[Erector spinae plane block for a pediatric patient undergoing thoracotomy]. / Torakotomi yapilan pediyatrik bir hastada erektör spina plan bloku.

We aimed to share our experience with erector spina plan block for postoperative analgesia after hydatid cyst operation in a six-year-old girl. Erector spina plan block is a new interfasial block defined by Forero in 2016. It has been reported that it can be used effectively in many different indications. Ultrasound guided erector spina plan block is a method that can be applied for postoperative analgesia after thoracotomy.

A comparison of angled (D-Blade) and Macintosh (C-MAC) videolaryngoscopes for simulated pediatric difficult airway: a randomized single-blind study.

BACKGROUND: Being prepared for difficult airway (DA) is nevertheless of great importance. Failed or delayed tracheal intubation (TI) can increase morbidity and mortality, and the pediatric population is more prone to hypoxia. With the development of different types of videolaryngoscope (VL), these have become the device of choice in patients with DA. Our primary aim was to compare intubation times with D-blade and Macintosh blade of Storz C-MAC in a simulated pediatric DA scenario with this randomized controlled trial. METHODS: Children aged 1-5 years scheduled for elective surgery were included in the study. Patients were randomized into two groups: the D-Blade (n = 20) and MAC (n = 21) groups. All children underwent inhalational induction, and a neuromuscular relaxant was routinely administered (rocuronium 0.6 mg.kg-1). After the appropriate size of semirigid foam neck collar had been positioned around the patient's neck, the D-Blade group patients were intubated using a size 2 D-Blade, and the MAC group patients used a size 2 VL Macintosh blade. Intubation, time was measured. Patients' modified Cormack-Lehane system scores (MCLS), pre and postintubation blood pressure values and heart rates, and complications during intubation were recorded. RESULTS: Demographic data were similar between the groups. There were also no significant differences in pre and postintubation heart rates, blood pressure, or SpO2 values (p > 0.05 for all). Mean intubation times for the MAC and D-Blade groups were 12.14 ± 2.79 s and 18.31 ± 10.86 s, respectively (p = 0.022). MCLS scores were lower in the D-Blade group (p = 0.030).

Erector spinae block for postoperative pain management in lumbar disc hernia repair.

PURPOSE: Lumbar disc herniation is the most common spinal disorder and various less invasive techniques such as microdiscectomy have been described. However, postoperative pain management in patients undergoing discectomy is still commonly inadequate. Erector spinae plane (ESP) block is a relatively easier technique with lower risks of complications, and can be performed to provide postoperative analgesia for various procedures. The current study aimed to determine the effect of ESP block on postoperative analgesia in patients who underwent elective lumbar disc herniation repair surgeries. METHODS: Fifty-four ASA I-II patients aged 18-65 years scheduled for elective discectomy surgery were included in the study. Patients were randomized either to the ESP or control group. Ultrasound-guided ESP block with 20 mL of 0.25% bupivacaine was performed preoperatively in the ESP group patients and a sham block was performed with 20 mL normal saline in the control group patients. All the patients were provided with intravenous patient-controlled analgesia devices containing morphine. Morphine consumption and numeric rating scale (NRS) scores for pain were recorded 1, 6, 12, and 24 h after surgery. RESULTS: A significantly lower morphine consumption was observed at 6, 12, and 24 h timepoints in the ESP group (p < 0.05 for each timepoint). Total morphine consumption at 24 h after surgery decreased by 57% compared to that of the control group (11.3 ± 9.5 mg in the ESP group and 27 ± 16.7 mg in the control group). NRS scores were similar between the two groups. CONCLUSION: This study showed that ESP block provided effective analgesia in patients who underwent lumbar disc herniation surgery. CLINICAL TRIALS REGISTRY: NCT03744689.

Subcapsular local anesthesia approach in percutaneous liver biopsy: less pain, more comfort

Background/aim: To compare the subjective level of pain in patients who underwent an ultrasound-guided percutaneous liver biopsy (PLB) after either pericapsular anesthesia (PA) or subcapsular anesthesia (SA), based on the numeric rating scale (NRS). Materials and methods: A total of 323 patients, mean age 51, range 21­82 years; 160 (49.5%) male, referred to the Interventional Radiology Clinic of Kocaeli University Faculty of Medicine for image-guided PLB, between June 2019 and May 2020 were included and randomized into two groups by anesthetic type; the first (n = 171) consisted of patients undergoing SA while the second (n = 152) included patients undergoing PA. The intensity of pain at 0, 1, and 6 h after PLB was evaluated between the groups using NRS. Results: At hours 0, 1, and 6, the median [range] NRS scores in the subcapsular and pericapsular groups were 2 [1­2] versus 3 [2­4] (P < 0.001), 1 [0­1] versus 1 [1­2] (P < 0.001), and 0 [0­0] versus 1 [0­1] (P < 0.001), respectively. Subgroup analysis revealed that the patients who underwent the subcostal procedure with subcapsular anesthesia reported the lowest pain scores and intercostal procedure with pericapsular anesthesia reported the worst pain scores for each time point: 0 h 1 [1­2] versus 3 [3­4], P < 0.001; 1 h 1 [0­1] versus 1 [1­2], P < 0.001; and 6 h 0 [0­0] versus 0 [0­1], P < 0.001, respectively. Conclusion: Subcapsular anesthesia is a well-tolerated procedure compared to a pericapsular procedure. Furthermore, the application of a subcapsular anesthetic with a subcostal approach was reported to result in the lowest pain and greatest patient comfort.

[Surgical anesthesia using ultrasound-guided penile nerve block for adult hemophilia patient]. / Eriskin hemofili hastasinda ultrason rehberliginde penil blok ile cerrahi anestezi.

Ultrasound-Guided Dorsal Penile Nerve (DPNB) Block was performed to provide surgical anesthesia for a 22 years old ASA II patient who had hemophilia A and was undergoing circumcision surgery. 20 ml of 0.25% bupivacaine was used for the DPNB. Surgery was completed under block without complication. Twenty-four hours of the analgesia was provided following surgery.

[The effect of thoracic paravertebral block on seroma reduction in breast surgery - a randomized controlled trial]. / Efeito do bloqueio paravertebral torácico na redução de seroma em cirurgia de mama ­ estudo randomizado controlado.

BACKGROUND: Increasing number of patients are being operated because of breast cancer. Seroma is the most common problem that occurs after surgery that increases morbidity. For postoperative pain management, Thoracic Paravertebral Block (TPVB) has long been considered the gold standard technique. With performing TPVB, sympathetic nerves are also blocked. OBJECTIVE: With this study, we aimed to search the effect of TPVB on seroma reduction in patients who undergo mastectomy and axillary node dissection surgery. METHODS: Forty ASA I-II female patients aged 18-65, who were scheduled to go under elective unilateral mastectomy and axillary lymph node resection were included to the study. Patients were randomized into two groups as TPVB and control group. Ultrasound guided TPVB with 20 mL 0.25% bupivacaine was performed at T1 level preoperatively to the TPVB group patients. All patients were provided with i.v. patient-controlled analgesia device. Seroma formation amounts, morphine consumptions and Numeric Rating Scale (NRS) scores for pain were recorded 24th hour postoperatively. RESULTS AND CONCLUSIONS: Mean seroma formation at postoperative 24th hour was 112.5±53.3 mL in the control group and 74.5±47.4 mL in the TPVB group (p=0.022). NRS scores were similar between two groups (p=0.367) at postoperative 24th hour but mean morphine consumption at postoperative 24th hour was 5.6±4 mg in the TPBV group, and 16.6±6.9 mg in the control group (p <0.001). TPVB reduces the amount of seroma formation while providing effective analgesia in patients who undergo mastectomy and axillary lymph node removal surgery.

The effect of thoracic paravertebral block on seroma reduction in breast surgery - a randomized controlled trial / Efeito do bloqueio paravertebral torácico na redução de seroma em cirurgia de mama - estudo randomizado controlado

Abstract Background: Increasing number of patients are being operated because of breast cancer. Seroma is the most common problem that occurs after surgery that increases morbidity. For postoperative pain management, Thoracic Paravertebral Block (TPVB) has long been considered the gold standard technique. With performing TPVB, sympathetic nerves are also blocked. Objective: With this study, we aimed to search the effect of TPVB on seroma reduction in patients who undergo mastectomy and axillary node dissection surgery. Methods: Forty ASA I-II female patients aged 18-65, who were scheduled to go under elective unilateral mastectomy and axillary lymph node resection were included to the study. Patients were randomized into two groups as TPVB and Control group. Ultrasound guided TPVB with 20 mL 0.25% bupivacaine was performed at T1 level preoperatively to the TPVB group patients. All patients were provided with i.v. patient-controlled analgesia device. Seroma formation amounts, morphine consumptions and Numeric Rating Scale (NRS) scores for pain were recorded 24th hour postoperatively. Results and conclusions: Mean seroma formation at postoperative 24th hour was 112.5 ± 53.3 mL in the control group and 74.5 ± 47.4 mL in the TPVB group (p = 0.022). NRS scores were similar between two groups (p = 0.367) at postoperative 24th hour but mean morphine consumption at postoperative 24th hour was 5.6 ± 4 mg in the TPBV group, and 16.6 ± 6.9 mg in the control group (p < 0.001). TPVB reduces the amount of seroma formation while providing effective analgesia in patients who undergo mastectomy and axillary lymph node removal surgery.

Resumo Introdução: Observa-se aumento do número de pacientes submetidos à cirurgia por neoplasia mamária. Seroma é a mais frequente complicação pós-operatória que aumenta a morbidade. Há muito tempo, considera-se o Bloqueio Paravertebral Torácico (BPVT) a técnica padrão-ouro para o controle da dor pós-operatória. O BPVT provoca, igualmente, o bloqueio da inervação simpática. Objetivo: Identificar o efeito do BPVT na redução de seroma em pacientes que realizaram mastectomia e dissecção dos linfonodos axilares. Método: Foram incluídas no estudo 40 pacientes do sexo feminino ASA I-II, entre 18 e 65 anos de idade, submetidas a mastectomia eletiva unilateral com ressecção de linfonodos axilares. As pacientes foram randomizadas em grupo BPVT e grupo controle. As pacientes do grupo BPVT foram submetidas ao BPVT guiado por ultrassom no nível de T1 e 20 mL de bupivacaína 0,25% foram administrados antes da cirurgia. Bomba de infusão IV ACP foi prescrita para todas as pacientes. Na 24ª hora pós-operatória foram registradas a quantidade de produção de seroma, o consumo de morfina e a avaliação da dor pela escala de avaliação numérica (NRS - do inglês Numeric Rating Scale). Resultados: A quantidade média de seroma na 24ª hora pós-operatória foi 112,5 ± 53,3 mL no grupo controle e 74,5 ± 47,4 mL no grupo BPVT (p = 0,022). Na 24ª hora pós-operatória a pontuação NRS foi semelhante nos dois grupos (p = 0,367), porém o consumo médio de morfina foi 5,6 ± 4 mg no grupo BPVT e 16,6 ± 6,9 mg no grupo controle (p < 0,001). Conclusões: O BPVT reduz a quantidade de seroma enquanto proporciona analgesia efetiva em pacientes que se submetem a mastectomia e remoção dos linfonodos axilares.

[Superficial cervical plexus block in ear surgery: A case report]. / Kulak cerrahisinde yüzeyel servikal pleksus blogu: Olgu sunumu.

The aim of this study was to share our experience with the application of a superficial cervical plexus block in the ear operation of a 59-year-old male patient. The superficial cervical plexus provides sensory innervation of the superficial structures of the anterolateral neck, ear, and shoulder. Ultrasound-guided cervical plexus block may be an alternative method for both anesthesia and analgesia in ear surgery.

Erector spinae plane block and thoracic paravertebral block for breast surgery compared to IV-morphine: A randomized controlled trial.

STUDY OBJECTIVE: Erector spinae plane (ESP) block is a novel regional anesthesia technique and gaining importance for postoperative pain management. Since it was first described, the clinicians wonder if this new simple technique can replace paravertebral block (PVB). We aimed to compare the postoperative analgesic effect of ESP block and PVB with a control group in breast surgeries. DESIGN: Randomized controlled trial. SETTING: Operating room. PATIENTS: Seventy-five ASA I-II patients aged 25-65, who were scheduled to go under elective unilateral breast surgery for breast cancer were included to the study. INTERVENTIONS: Patients were randomized into three groups as ESP, PVB, and Control group. Ultrasound (US) guided ESP block and PVB with 20 ml 0.25% bupivacaine was done preoperatively to the patients according to their groups. MEASUREMENTS: All patients were provided with iv patient-controlled analgesia device for postoperative analgesia. Morphine consumptions and numeric rating scale (NRS) scores for pain were recorded at 1st, 6th, 12th and 24th hours postoperatively. MAIN RESULTS: There was a statistically significant difference between ESP and Control groups (p < 0,001) and between PVB and Control groups (p < 0,001), while there was no difference between ESP and PVB groups (p > 0,05) for 24-hour morphine consumptions. There was a significant difference between PVB and Control groups for NRS at postoperative 1st and 6th hour (p = 0.018 and p = 0.027 respectively). CONCLUSIONS: This study has shown that US guided ESP block and PVB provided adequate analgesia in patients undergoing breast surgery and have an opioid sparing effect by reducing morphine consumption. Clinical Trials Registry: NCT03480958.

Analgesic effect of the bi-level injection erector spinae plane block after breast surgery: A randomized controlled trial.

OBJECTIVES: Due to the complex breast innervation, postoperative analgesia after breast surgery is a challenge for the anesthesiologists. The erector spinae plane block (ESPB) is a newly defined promising technique for this purpose. The main purpose of this study was to evaluate the analgesic efficacy of the ultrasound-guided ESPB in breast surgery, monitoring its effect on the postoperative opioid consumption. METHODS: Fifty female patients, who were scheduled to undergo elective breast surgery, with the American Society of Anesthesiology physical score I-II, and aged between 25 and 70 years, were included into the study. Patients were randomized into two groups, as the ESPB and the control group. All patients in the ESPB group received a bi-level (T2-T4) ultrasound-guided ESPB with 20 ml 0.25 % bupivacaine (10 ml for each level) preoperatively. An intravenous patient-controlled analgesia device for the postoperative analgesia was given to all patients. The numeric rating scale (NRS) scores for pain and postoperative morphine consumptions were recorded at the 1st, 6th, 12th, and 24th hour postoperatively. RESULTS: Postoperative morphine consumption was significantly lower in the ESPB group compared to the control group at the postoperative 6th, 12th, and 24th hour (p<0.001 for each time interval). The morphine consumption at the 24-hour was reduced by 75%. There was no significant difference in the NRS scores (median NRS values were 2, 1, 0, 0, and 2, 2, 1, 1, respectively). CONCLUSION: Our study has shown that a significant opioid-sparing analgesic effect in patients undergoing breast surgery could be achieved with a US-guided bi-level ESP block.

Defining the Indications and Levels of Erector Spinae Plane Block in Pediatric Patients: A Retrospective Study of Our Current Experience.

Aim  The primary aim of this study was to evaluate the indications, effectiveness, application levels, and local anesthetic (LA) dosages used in erector spinae plane block (ESPB) in pediatric patients based on our clinical data. The secondary aim was to compare previously reported pediatric ESPBs with our data and to prepare a mini-guide for future clinical applications. Materials and methods One hundred and forty-one pediatric patients who received ESPB and were operated by the Department of Pediatric Surgery were included in this retrospective observational study. ESPB is routinely performed with 0.5 ml/kg 0.25% bupivacaine (max 20 ml). Demographic data and the type of surgery were recorded. Face, Legs, Activity, Cry, and Consolability (FLACC) or Numeric Rating Scale (NRS) scores, analgesic requirements, and the type of analgesic administered at postoperative period were recorded. Results ESPB was applied using three different techniques, the classic approach, the transverse approach, and the Aksu approach. Unilateral ESPB was performed on 112 patients, while 29 received a bilateral block. ESPB used for 13 different indications. Conclusion ESPB is a relatively safe and effective procedure for achieving opioid-free postoperative analgesia in many different surgical procedures in pediatric patients.

Ultrasound-guided dorsal penile nerve block vs neurostimulator-guided pudendal nerve block in children undergoing hypospadias surgery: A prospective, randomized, double-blinded trial.

BACKGROUND AND AIMS: Hypospadias is a common congenital malformation in pediatric patients. Surgical repair of this malformation is a painful procedure and has long-term effects. Pudendal and penile nerve blocks are commonly preferred techniques for maintaining postoperative analgesia. However, the conventional landmark-based penile block technique involves numerous potential complications and provides a shorter analgesic period compared to the pudendal block. A promising ultrasound-guided dorsal penile nerve block was recently described. We aimed to compare the analgesic effectiveness of ultrasound-guided penile nerve block with that of neurostimulator-guided pudendal nerve block. METHOD: Thirty-three patients aged 1-7 years were included in this prospective, double-blinded, randomized controlled trial. Patients were divided into two groups and received either ultrasound-guided dorsal penile nerve block or neurostimulator-guided pudendal nerve block. All blocks were performed by the same two anesthesiologists, and the same surgeons performed the surgical procedures. The Face, Legs, Activity, Cry, and Consolability (FLACC) scale was used for postoperative pain management. The primary outcome of the study was time to first analgesic requirement. Secondary outcomes were FLACC scores at different time points, and types and cumulative doses of analgesic drugs. RESULTS: Dorsal penile nerve block provided longer analgesia than pudendal nerve block (32.29 ± 5.47 hours and 21.13 ± 3.53 hours, respectively; differences in mean: 11.16, 95% CI: 7.873-14.465) (P < .001). FLACC scores at the time of first analgesic requirement were significantly lower in dorsal penile nerve block group than pudendal nerve block group (median [IQR]: 2 [2-2.5] and 3 [3-5], respectively; differences in median: -1, 95% CI: -1.851 to -0.149) (P < .001). CONCLUSION: Ultrasound-guided dorsal penile nerve block provided a longer analgesic period and reduced opioid consumption compared to neurostimulator-guided pudendal nerve block.

Do we still need central blocks while we have erector spinae plane block? Case of 2. 5 month old infant / Ainda precisamos de bloqueios centrais enquanto temos o bloqueio do eretor da espinha? Caso de criança de 2, 5 meses de idade

Abstract Erector spinae plane block is gaining popularity both for its ease of application and as its comparable effect on postoperative analgesia with central regional techniques like paravertebral block or epidural anesthesia. Its use for many indications has been reported in the literature for pediatric patients. We would like to share our experiences in a 2.5-month infant scheduled for thoracotomy for a giant congenital cyst. Single shot erector spinae plane block was done at T4 level before the start of the surgery for both surgical and postoperative analgesia. No complication was seen during both surgery and follow up period. Erector spinae plane block with the combination of paracetamol was adequate for pain relief.

Resumo O bloqueio do plano do músculo eretor da espinha tem ganhado popularidade, tanto pela facilidade de aplicação quanto pelo efeito comparável em analgesia pós-operatória com técnicas regionais centrais, como o bloqueio paravertebral ou a anestesia peridural. Seu uso tem sido relatado na literatura para muitas indicações em pacientes pediátricos. Gostaríamos de compartilhar nossas experiências no caso de um bebê de 2,5 meses de idade programado para toracotomia para excisão de um cisto congênito gigante. O bloqueio do plano do eretor da espinha dorsal com injeção única foi realizado no nível de T4 antes do início da cirurgia para analgesia cirúrgica e pós-operatória. Nenhuma complicação foi observada durante a cirurgia e o período de acompanhamento. O bloqueio do plano do eretor da espinha com a combinação de paracetamol foi adequado para o alívio da dor.