Programmed intermittent bolus infusion vs. continuous infusion for erector spinae plane block in video-assisted thoracoscopic surgery: A double-blinded randomised controlled trial.

BACKGROUND: The optimal form of administration for erector spinae plane block has not been established. OBJECTIVE: To compare the efficacy of programmed intermittent bolus infusion (PIB) and continuous infusion for erector spinae plane block. DESIGN: A prospective, randomised, double-blind study. SETTING: A single centre between June 2019 and March 2020. PATIENTS: Included patients had an American Society of Anesthesiologists physical status 1 to 3 and were scheduled for video-assisted thoracic surgery. INTERVENTIONS: Patients were randomised to receive continuous infusion (0.2% ropivacaine 8 ml h-1; Group C) or PIB (0.2% ropivacaine 8 ml every 2 h; Group P). MAIN OUTCOME MEASURES: The primary outcome was the number of desensitised dermatomes in the midclavicular line, measured 21 h after first bolus injection. RESULTS: Fifty patients were randomly assigned to each group; finally, the data of 24 and 25 patients in Group C and P, respectively, were analysed. The mean difference in the number of desensitised dermatomes in the midclavicular line at 5 and 21 h after the initial bolus administration was 1.0 [95% confidence interval (CI) 0.5 to 1.5] and 1.6 (95% CI 1.1 to 2.0), respectively, which was significantly higher in Group P than in Group C (P < 0.001). The median difference in rescue morphine consumption in the early postoperative period (0 to 24 h) was 4 (95% CI 1 to 8) mg, which was significantly lower in Group P (P = 0.035). No significant difference in the postoperative numerical rating scale score was found between the groups. CONCLUSIONS: PIB for erector spinae plane block in video-assisted thoracic surgery resulted in a larger anaesthetised area and required a lower anaesthetic dose to maintain the analgesic effect. Therefore, it is more suitable for erector spinae plane block than continuous infusion. TRIAL REGISTRATION: UMIN Clinical Trials Registry (UMIN-CTR, ID: UMIN000036574, Principal investigator: Taro Fujitani, 04/22/2019, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000041671).

Programmed intermittent bolus infusion versus continuous infusion of 0.2% levobupivacaine after ultrasound-guided thoracic paravertebral block for video-assisted thoracoscopic surgery: A randomised controlled trial.

BACKGROUND: The analgesic benefits of programmed intermittent bolus infusion for thoracic paravertebral block remain unknown. OBJECTIVE: The aim of this study was to compare the analgesia from intermittent bolus infusion with that of a continuous infusion after thoracic paravertebral block. DESIGN: A randomised controlled study. SETTING: A single centre between December 2016 and November 2017. Seventy patients scheduled for video-assisted thoracoscopic surgery were included in the study. INTERVENTION(S): Patients were randomly assigned to receive 0.2% levobupivacaine via continuous infusion (5 ml h, continuous group) or programmed intermittent bolus infusion (15 ml every 3 h, bolus group) after an initial 15-ml bolus injection of 0.2% levobupivacaine. MAIN OUTCOME MEASURES: The main outcome was the amount of rescue fentanyl (per kg of body weight) consumed within 24 h after surgery. Secondary outcomes were postoperative pain scores, plasma levobupivacaine concentrations and the number of dermatomes anaesthetised. RESULTS: There was no significant difference between the continuous and bolus groups in the postoperative consumption of fentanyl (median [interquartile range] 5.5 [4 to 9.5] µg kg versus 6 [3.5 to 9] µg kg respectively, P = 0.45) and postoperative pain scores within 24 h. At 20 h after initiating the infusions, there was no statistically significant difference between the two groups in terms of the plasma levobupivacaine concentration. The number of dermatomes anaesthetised to pinprick and cold testing was significantly greater in the bolus group. CONCLUSION: Our findings suggest that postoperative pain and opioid usage are similar with either programmed intermittent bolus infusion or continuous infusion after thoracic paravertebral block. Programmed intermittent bolus infusion provides a wider sensory blockade and could benefit patients requiring a wider extent of anaesthesia. TRIAL REGISTRATION: UMIN Clinical Trials Registry (UMIN-CTR; URL: http://umin.ac.jp/ctr/, ID: UMIN000023378).

Comparison of analgesic efficacy between two approaches of paravertebral block for thoracotomy: A randomised trial.

BACKGROUND: Although several approaches for ultrasound-guided thoracic paravertebral block have been introduced, little is known regarding the differences in analgesic efficacy. We conducted this prospective randomised trial to examine whether the type of approach for ultrasound-guided thoracic paravertebral block could affect analgesic quality in thoracotomy. METHODS: Patients scheduled for video-assisted thoracotomy were randomly allocated into two groups by block technique: the intercostal approach (group IC) or the paralaminar approach (group PL). At the start and end of surgery, 20 mL of 0.5% ropivacaine was injected, followed by a continuous infusion of 0.2% ropivacaine at 5 mL h-1 . We also started intravenous fentanyl patient-controlled analgesia at 0.5 µg kg-1  h-1 and bolus dose of 15 µg. The main outcome was the number of rescue fentanyl use. We also evaluated postoperative pain scores and number of blocked dermatomes showing a reduced sensation. RESULTS: Enrolment was ceased because of implementation of a minimally invasive surgical method. Overall, 42 subjects completed the trial for analysis. The number of rescue fentanyl use in group PL was significantly less than that in group IC at 3, 6, 12 and 24 hour postoperatively. The numerical rating scale (NRS) at rest in group PL was significantly lower at 1, 3, 6, and 12 hour postoperatively. Patients in Group PL developed significantly wider sensory block level (median (IQR [range]); 4 (4-5 [2-7])) than those in Group IC (3 (3-3 [2-9])). CONCLUSIONS: We suggested that paralaminar approach provided superior analgesia for thoracotomy rather than the intercostal approach.

Ultrasound-guided thoracic paravertebral block by the paralaminar in-plane approach using a microconvex array transducer: methodological utility based on anatomical structures.

OBJECTIVE: We evaluated the analgesic feasibility of paralaminar in-plane (PL) approach for ultrasound-guided thoracic paravertebral block (USG-TPVB). As the needle trajectory was expected to be closely affected by the distance from the skin to the lamina-transverse process junction (LTPJ), we examined the correlativity between them on computed tomography (CT) or ultrasonography. METHODS: Thirty-two patients undergoing thoracotomy were recruited. We measured the distances between the skin and LTPJ using preoperative CT (S-L) and procedural ultrasonography (US-L). At the beginning and the end of the surgery, 20 ml of 0.5% ropivacaine was injected. The level of sensory block and postoperative numerical pain rating scale (NRS) was assessed. Relationships among the measured parameters and the agreement of the needle depth (ND) with S-L and US-L were evaluated using Pearson's correlation coefficient and Bland-Altman analysis. RESULTS: S-L and US-L were strongly correlated with ND (r = 0.72 and r = 0.81, respectively) but not with BMI. The Bland-Altman analysis showed that the mean percent differences between the ND and S-L or ND and US-L were -9.6 and 20.1%, respectively. Catheters were inserted 18.6 mm lateral from the midline on average. Analgesia extended to 3-5 dermatomes in 29 patients, and the median NRS was 2 at 1, 6, 12, and 24 h after surgery, respectively. CONCLUSIONS: We demonstrated that PL approach provided feasible analgesia for thoracotomy and the ND was significantly correlated with the morphometric values. This technique allowed for inner catheter insertion route targeting longer anteroposterior thoracic paravertebral space length; this may reduce potential risk of pleural puncture for USG-TPVB. Trial registry number This study was registered in the UMIN Clinical Trials Registry (UMIN-CTR). (URL: http://umin.ac.jp/ctr/ , ID:UMIN000014821).

[Comparison of Analgesic Efficacy between Posterior and Lateral Transversus Abdominis Plane Block Techniques for Laparoscopic Gynecological Surgery].

BACKGROUND: Posterior transversus abdominis plane (TAP) block has been considered as a useful technique for lower abdominal postoperative analgesia, but in ultrasound-guided block, its efficacy and usability are still unknown. We prospectively compared the analgesic efficacy among posterior and lateral TAP block and with control group in laparoscopic gynecological surgery. METHODS: 29 patients were randomly assigned to a study group. Ultrasound-guided TAP block was performed before the operation. In the posterior group (n =10), a needle was inserted from posterior to the middle axillary line, and its tip was centrally positioned at the origin of the transversus abdominis muscle. In the lateral group (n=10), a needle was inserted from the middle axillary line, and the tip was peripherally positioned at the surface of the transversus abdominis muscle. Visual analog scale (VAS), the use frequency of fentanyl rescue dose, and the period of time until initial rescue use after the operation were measured. RESULTS: In posterior group, pain scores both at rest and on movement were significantly lower than other groups at early phase (P<0.05). The number of uses of the fentanyl rescue dose was smaller in posterior group than in control group in the first 6 postoperative hours (1±1.2 vs 3±1.5, P<0.05). CONCLUSIONS: Ultrasound-guided posterior TAP block could become a more useful tool for postoperative analgesia. We presumed that its additional effect is caused from reduction of visceral pain related to sympathetic nerve block.

Comparison of ultrasound-guided erector spinae plane block and thoracic paravertebral block for postoperative analgesia after video-assisted thoracic surgery: a randomized controlled non-inferiority clinical trial.

BACKGROUND AND OBJECTIVES: The anesthetic characteristics of ultrasound-guided erector spinae plane block (ESPB) remain unclear. We compared the analgesic efficacies of ESPB and thoracic paravertebral block (TPVB) for analgesia after video-assisted thoracic surgery (VATS). METHOD: In this prospective randomized non-inferiority trial, 88 patients undergoing VATS randomly received ESPB or TPVB. All patients received continuous infusion of 0.2% levobupivacaine (8 mL/hour) after injection of a 20 mL 0.2% levobupivacaine bolus. The primary outcome was median differences between the groups in postoperative numerical rating scale (NRS) scores at rest, 24 hours postoperatively. RESULTS: Eighty-one patients completed the study. The median difference in NRS scores at rest 24 hours postoperatively was 1 (range 0-1), demonstrating the non-inferiority of ESPB to TPVB. NRS scores at rest were significantly lower in the TPVB group at 1, 2 and 24 hours postoperatively (p=0.02, 0.01 and 0.006, respectively). NRS scores on movement were similar. More dermatomes in parasternal regions were anaesthetized in the TPVB group (p<0.0001). Total plasma levobupivacaine concentrations were significantly lower in the ESPB group within 20 hours postoperatively (p=0.036). CONCLUSIONS: The analgesic effect of ESPB after VATS was non-inferior to that of TPVB 24 hours postoperatively. TRIAL REGISTRATION NUMBER: UMIN000030658.

A comparison of protective effects between L-histidine and hypothermia against ischemia-induced neuronal damage in gerbil hippocampus.

An increase in the histamine concentration in the brain has been demonstrated to provide protective effects against ischemia/reperfusion brain injury. Since hypothermia and barbiturates are also regarded to protect ischemic brains, effects of postischemic treatments were compared in gerbils between mild hypothermia and intraperitoneal administration of L-histidine, a precursor of histamine. Furthermore, effects of thioperamide, a histamine H(3) receptor antagonist, were evaluated in histidine-treated gerbils after 60 days. Transient forebrain ischemia for 4 min at 37 degrees C provoked severe neuronal damage in the hippocampal CA1 pyramidal cells after 7 days. Postischemic hypothermia (33 degrees C) for 3 h under pentobarbital anesthesia alleviated neuronal death, and the number of preserved neurons was 77+/-56/mm (mean+/-S.D., n=14). The effect of L-histidine injected three times, immediately, 6 h, and 24 h after reperfusion (1,000 mg/kg, i.p., each), was more prominent than that of hypothermia, and the number of preserved neurons was 142+/-55/mm (n=14). When the histologic outcome was evaluated after 60 days, most neurons were damaged in both the hypothermic and histidine groups. The improvement of the histologic outcome was observed even after 60 days in animals injected with thioperamide, immediately and 6 h after reperfusion (5 mg/kg, s.c., each), with three injections of l-histidine. The number of preserved neurons was 133+/-88/mm (n=10), while that in the hypothermic group was 7+/-15 (n=10). Activation of the central histaminergic system provides beneficial effects against cerebral ischemia.

Reduction of the infarct size by simultaneous administration of L-histidine and diphenhydramine in ischaemic rat brains.

AIMS: While diphenhydramine is a histamine H(1) receptor antagonist, the agent has been shown to inhibit histamine-N-methyltransferase, a histamine inactivating enzyme in the brain. Since an increase in the brain concentration of histamine ameliorates reperfusion injury after cerebral ischaemia, effects of postischaemic administration of diphenhydramine were evaluated in rats treated with l-histidine, a precursor of histamine. METHODS: The right middle cerebral artery was occluded for 2h, and the infarct size was determined 24h after reperfusion of cerebral blood flow. Brain oedema was evaluated by comparing the area of the right hemisphere to that of the left hemisphere. RESULTS: Focal cerebral ischaemia provoked marked damage in saline-treated control rats, and infarct volumes in the striatum and cerebral cortex were 56 (49-63) mm(3) and 110 (72-148) mm(3), respectively (means and 95% confidence intervals, n=6). Administration of l-histidine (1000mg/kg, intraperitoneal) immediately after reperfusion did not affect the infarct size. Simultaneous administration of diphenhydramine (20mg/kg, intraperitoneal) with l-histidine reduced the infarct size to 25% and 21% of that in the control group, respectively. The combination therapy completely reduced ischaemia-induced brain oedema. CONCLUSION: Because histamine H(1) action does not influence ischaemic brain damage, elevation of the central histamine concentration by blockade of histamine-N-methyltransferase may be a likely mechanism responsible for the alleviation.

Alleviation of ischemia-induced brain edema by activation of the central histaminergic system in rats.

We have reported that facilitation of central histaminergic activity prevents the development of ischemia-induced brain injury. Since cerebral edema is a major cause of brain damage, we studied effects on brain edema of postischemic administration of L-histidine, a precursor of histamine, and thioperamide, a histamine H(3)-receptor antagonist, both of which enhance central histaminergic activity. Focal cerebral ischemia for 2 h was provoked by transient occlusion of the right middle cerebral artery in rats, and the water content and infarct size were determined 24 h after reperfusion. Changes in the extracellular concentration of histamine were examined in the striatum by a microdialysis procedure, and effects of these compounds were evaluated. Repeated administration of L-histidine (1000 mg/kg x 2, i.p.), immediately and 6 h after reperfusion, reduced the increase in the water contents in ischemic regions. Simultaneous administration of thioperamide (5 mg/kg, s.c.) with L-histidine (1000 mg/kg, i.p.) completely prevented edema formation and alleviated brain infarction, although a single dose of L-histidine, immediately after reperfusion, showed no benefits. The striatal histamine level was gradually increased after reperfusion as well as during ischemia. Simultaneous administration of thioperamide with L-histidine markedly increased the brain histamine concentration, and the value increased up to 230% of that in the saline group 5 - 6 h after reperfusion. L-Histidine alone did not affect the increase in the histamine output after ischemia. These findings suggest that further activation of the central histaminergic system after initiation of cerebral ischemia prevents development of ischemia-induced brain edema.