Comparison of Changes in the Optic Nerve Sheath Diameter Following Thoracic Epidural Normal Saline Injection in Laparoscopic Surgery.

BACKGROUND: Thoracic epidural analgesia is useful for postoperative pain control after upper abdominal surgery. However, epidural analgesia in patients undergoing laparoscopic surgery may potentiate an increase in intracranial pressure (ICP). ICP can be effectively evaluated by measuring the optic nerve sheath diameter (ONSD). OBJECTIVES: The purpose of this study is to investigate changes in the ONSD following thoracic epidural normal saline injection during laparoscopic surgery. STUDY DESIGN: Prospective randomized trial. SETTING: An interventional pain management clinic in South Korea. METHOD: This study included 60 patients receiving thoracic epidural catheterization for postoperative pain control following laparoscopic or open gastrectomy. Patients were divided into 3 groups. The open group consisted of patients undergoing open gastrectomy without epidural normal saline injection. The lapa-saline and lapa groups consisted of patients undergoing laparoscopic gastrectomy with and without 10 mL epidural normal saline injection, respectively. The ONSD was measured using ultrasound at 4 time points. RESULTS: The lapa-saline group showed the most pronounced increase in the ONSD compared to the open and lapa groups at the time points of T1 and T2. Only the lapa-saline group demonstrated 4 patients with ONSD values of more than 5.8 mm. The increase in the ONSD continued even after the deflation of pneumoperitoneum in the lapa-saline group, whereas the ONSD in the lapa group returned to near baseline value after the deflation of pneumoperitoneum. LIMITATIONS: Epidural normal saline was injected instead of a local anesthetic to prevent the occurrence of hypotension. However, the injection of epidural normal saline is considered to be the same physiological condition causing elevation of ICP compared with epidural injection with local anesthetics. CONCLUSIONS: The lapa-saline group showed the most pronounced increase in the ONSD. The ONSD values higher than 5.8 mm were observed only in the lapa-saline group. The increase in the ONSD continued even after the deflation of pneumoperitoneum only in the lapa-saline group.

The Effect of Normal Saline Injection Volumes on the Optic Nerve Sheath Diameter during Thoracic Epidural Analgesia.

BACKGROUND: Saline or local anesthetic injection into the epidural space increases intracranial pressure (ICP), at least transiently. Measurement of the optic nerve sheath diameter (ONSD) using ocular ultrasonography is one of the noninvasive methods for ICP assessment. OBJECTIVES: The purpose of this study is to investigate the effects of the different volume on the ONSD and cerebral oxygen saturation (rSO2) during thoracic epidural saline injection under awake conditions. STUDY DESIGN: Prospective randomized, controlled trial. SETTING: An interventional pain management practice in South Korea. METHODS: This study included 71 patients receiving thoracic epidural catheterization for pain management, following upper abdominal or thoracic surgery. Following successful epidural space confirmation, patients were randomly allocated to receive 5 mL (5 mL group), 10 mL (10 mL group), and 20 mL (20 mL group) of epidural normal saline. Transorbital sonography was performed to measure the ONSD. This was measured at 3 mm posterior to the optic nerve head. An rSO2 was measured using cerebral oximeter sensors. RESULTS: All 3 groups showed significant increases of ONSD from 10 minutes to 40 minutes as compared to baseline (before procedure). Among the 3 groups, the 20 mL group demonstrated the most significantly increased ONSD, as compared to the 5 mL and 10 mL groups. At the 20 minute and 40 minute time points, the ONSD showed a volume-dependent increase (P = 0.0005, P = 0.014). All 3 groups showed the rSO2 to be distributed between 60~70% without any statistical difference. LIMITATIONS: We could not determine the returning point of the normalized ONSD value. CONCLUSION: Twenty milliliters of normal saline epidural injection resulted in a significant increase of ONSD, as compared to the 5 mL and 10 mL groups. Our results also indicate that an increase of ONSD occurs in accordance with the injected volume of normal saline.

Comparison of Intravascular Injection Incidences and Technical Easiness Between Anteroposterior and Oblique Approaches During S1 Transforaminal Epidural Injection.

BACKGROUND: Transforaminal epidural injection (TFEI) is a useful intervention for radicular leg pain. Compared to TFEI in lumbar level, S1 TFEI is reported to have higher incidence rates of intravascular injection as well as technical difficulties. OBJECTIVE: The purpose of this study is to compare the incidence rates of intravascular injection and foramen passage time between anteroposterior (AP) and oblique (OB) approaches. STUDY DESIGN: Prospective randomized trial. SETTING: An interventional pain management practice in South Korea. METHODS: One hundred forty-seven patients receiving S1 TFEI for radicular leg pain were randomly assigned to one of 2 approach methods (AP view vs OB view). For S1 TFEI in the OB view group, lineup of the L5-S1 endplate was performed by adjusting the cephalad-caudad tilt. Then C-arm was rotated at an ipsilateral oblique angle, approximately 10° to 15°. After final confirmation of intravascular injection with real time fluoroscopy, the foramen passage time and amount of radiation exposure during S1 TFEI were measured. RESULTS: The incidence rate of intravascular injection in the AP view group was 24.2% (24/99), whereas that of intravascular injection in the OB view group was 10.1% (17/99, P = 0.008). The radiation dose required to pass the S1 foramen was significantly higher in the AP view group than in the OB view group (51.3 ± 27.2 cGy/cm2 vs 41.0 ± 17.0 cGy/cm2, P = 0.002). The foramen passage time during S1 TFEI was significantly higher in the AP view group than in the OB view group (103.5 ± 44.1 second vs 84.9 ± 21.0 second, P = 0.001). The failure rate of S1 TFEI was significantly higher in the AP view group than in the OB view group (13% vs 4%, P = 0.022). LIMITATION: The physicians involved in the present study were not blinded to the type of approach method (AP view vs OB view) by fluoroscopy. CONCLUSION: Our study demonstrated reduced incidence rates of intravascular injection and reduced foramen passage time and radiation dosage with the use of OB view method during S1 TFEI.

Studies of Supraorbital Notch and Foramen Using 3-Dimensional Facial Bone CT Scans.

BACKGROUND: The supraorbital foramen or notch is located at the superior orbital rim. Previous studies have reported anatomical variations in these structures. However, the results varied depending on races and the measurement method used. OBJECTIVE: The purpose of this study is to identify the morphological features of supraorbital foramen or notch based on locational relationship using images of 3-dimensional (3D) facial bone CT scans. STUDY DESIGN: Retrospective study. SETTING: University hospital emergency department.  METHODS: Identification and analysis of patients who have undergone facial bone 3D CT were performed using Clinical Data Warehouse v 2.5 (CDW, Planit Healthcare, Seoul, Korea). The search word that we used with the CDW for analysis was "facial bone 3D CT".First, the region of the supraorbital rim was examined to clarify whether or not the supraorbital foramen or notch was present. Second, the diameter of the supraorbital foramen or notch was measured. Lastly, the distance from midpoint (nasion) to the supraorbital notch or foramen was measured. RESULTS: The supraorbital notch was found more frequently than the supraorbital foramen. Among supraorbital double types, the coexistence of notch and foramen was found more frequently than the coexistence of notch and notch or foramen and foramen. The diameter of supraorbital notch was wider than the supraorbital foramen, which was located more laterally from the nasion than the supraorbital notch. LIMITATION: The actual size of the facial image or the skull size of the patient was not considered, which might affect the distance of supraorbital notch or foramen from the midline. CONCLUSION: Supraorbital notch was more frequently found than the supraorbital foramen. The supraorbital notch had a wider diameter and was more centrally located than the supraorbital foramen.

Changes in tapered endotracheal tube cuff pressure after changing position to hyperextension of neck: A randomized clinical trial.

BACKGROUND: Endotracheal tube (ETT) with a tapered-shaped cuff had an improved sealing effect when compared to ETTs with a conventional cylindrical-shaped cuff. Positional change and neck movement typically displace an ETT and change the intracuff pressure. The aim of the current study was to compare the ETT cuff pressure in the TaperGuard ETT vs the conventional ETT after a change from the supine, neutral position to the extension of the neck and semi-Fowler position for thyroid surgery. METHODS: This prospective, randomized clinical trial included 50 patients undergoing thyroidectomy. Patients were randomly allocated into one of the 2 groups: tracheal intubation with the TaperGuard ETT or with a conventional ETT. The ETT cuff was inflated with air and the ETT cuff pressure was set initially at 20 cmH2O using a calibrated cuff manometer. ETT cuff pressure and distance from carina to ETT tip were measured at supine and semi-Fowler positions with neck extension. RESULTS: After the position change, the ETT tip migrated cephalad and cuff pressure increased in the majority of cases. ETT cuff pressure was significantly higher in the TaperGuard group than the conventional group (28.0 ±â€Š6.6 cmH2O and 22.8 ±â€Š4.5 cmH2O, respectively, P = .001). The degree of cephalad displacement of the ETT tip was comparable between the 2 groups (19.4 ±â€Š6.31 mm in TaperGuard group and 21.9 ±â€Š6.9 mm in conventional group, P = .12). CONCLUSIONS: After the position change from supine to hyperextension of the neck, the ETT cuff pressure was higher in the TaperGuard ETT than in the conventional ETT, although the extent of displacement of the ETT was comparable between the 2 groups.

Comparison of the effects of normal and low blood pressure regulation on the optic nerve sheath diameter in robot assisted laparoscopic radical prostatectomy.

BACKGROUND: Robot-assisted laparoscopic radical prostatectomy is an advanced and popular surgical technique. However, increased intracranial pressure which is caused by CO2 pneumoperitoneum and Trendelenburg position is the main cerebrovascular effect. Measurement of optic nerve sheath diameter using ocular ultrasound is a noninvasive and reliable method for the assessment of intracranial pressure. The primary endpoint of this study was to identify whether low blood pressure regulation has any benefit in attenuating an increase of optic nerve sheath diameter during robot-assisted laparoscopic radical prostatectomy. METHODS: Optic nerve sheath diameter and cerebral oxygen saturation were measured at baseline (supine position), one and two hours after pneumoperitoneum and Trendelenburg position respectively, and after return to supine position in normal (n = 27) and low blood pressure groups (n = 24). RESULTS: Mean optic nerve sheath diameter values measured at one and two hours after pneumoperitoneum and Trendelenburg position were significantly increased compared to the baseline value (P < 0.001 in normal blood pressure group; P = 0.003 in low blood pressure group). However, the mean optic nerve sheath diameter and cerebral oxygen saturation measured at any of the time points as well as degrees of change between the two groups did not show any significant changes. The peak values of optic nerve sheath diameter in normal and low blood pressure groups demonstrated 14.9% and 9.2% increases, respectively. CONCLUSIONS: Low blood pressure group demonstrated an effect in maintaining an increase of optic nerve sheath diameter less than 10% during CO2 pneumoperitoneum and Trendelenburg position.

Incidence of inadvertent intercostal or epidural spread during thoracic sympathetic ganglion block.

BACKGROUND: Sympathetic blocks (SBs) have been used widely to relieve the symptoms of sympathetically maintained pain (SMP). The thoracic sympathetic ganglion is not separated from somatic nerves by muscles and connective tissue. The upper thoracic ganglion runs along the posterior surface of the vertebral column in close proximity to the adjacent epidural region. This anatomical difference leads to frequent epidural and intercostal spread in cases of thoracic SBs. The purpose of this study was to investigate the incidence of inadvertent intercostal and epidural injections during thoracic SBs. METHODS: Twenty-two patients who were suffering from complex regional pain syndrome or lymphedema after breast cancer surgery were managed with two or three times of thoracic SBs. Therefore, injections of 63 thoracic SBs from 22 patients were enrolled in this study. An investigator who did not attend the procedure evaluated the occurrence of intercostal or epidural spread using anteroposterior fluoroscopic images. RESULTS: The overall incidence of inadvertent intercostal or epidural spread of contrast was 47.5%. Among the inadvertent injections, intercostal spread (34.9%) was more frequent than epidural spread (12.6%). Only 52.5% of the thoracic SBs demonstrated successful contrast spread without any inadvertent spread. The mean difference in skin temperature between the blocked and unblocked sides was 2.5 ± 1.8ºC. Fifty-nine (93.6%) injections demonstrated more than 1.5ºC difference. CONCLUSIONS: Thoracic SBs showed a high incidence (47.5%) of inadvertent epidural or intercostal injection. Thus, special attention is required for the diagnosis of SMP or the injection of any neurolytic agent around sympathetic ganglion.

Ultrasound-Guided Block of the Axillary Nerve: A Prospective, Randomized, Single-Blind Study Comparing Interfascial and Perivascular Injections.

BACKGROUND: The ultrasound-guided block of the axillary nerve may be complicated in cases in which the posterior circumflex humeral artery (PCHA) follows an abnormal course. OBJECTIVES: To develop a new technique that does not rely on direct visualization of the PCHA or the axillary nerve, and to compare interfascial injection and conventional perivascular injection for a block of the axillary nerve. STUDY DESIGN: A prospective randomized study. SETTING: An interventional pain-management practice in a university hospital. METHODS: A total of 56 patients received ultrasound-guided block of the axillary nerve with either interfascial injection (IF Group) or perivascular injection with nerve stimulation (PV Group). The primary outcome was procedure duration, defined as the time interval from when the transducer contacted the skin to when the needle was removed from the skin. RESULTS: The mean procedure time was significantly shorter in the IF Group than in the PV Group (64 seconds [SD 28.3] vs. 135 seconds [50.3], difference of -71.4 seconds; 95% confidence interval, -93.2 to -49.5) (P < 0.001). There were no differences in secondary outcomes, including the quality of blocks, between the 2 groups. LIMITATIONS: The practitioner was not blinded to the group to which the patients belonged. CONCLUSIONS: Ultrasound-guided block of the axillary nerve with interfascial injection can be performed without placing the needle near the PCHA. KEY WORDS: Block of axillary nerve, ultrasound-guided block, posterior circumflex humeral artery, interfascial injection.

Correlation of Perfusion Index Change and Analgesic Efficacy in Transforaminal Block for Lumbosacral Radicular Pain.

Transforaminal epidural injection is used to treat radicular pain. However, there is no objective method of assessing pain relief following transforaminal injection. Perfusion index is a metric for monitoring peripheral perfusion status. This study evaluates the correlation between perfusion index change and analgesic efficacy in transforaminal blocks for lumbosacral radicular pain. We retrospectively analyzed data of 100 patients receiving transforaminal block for lumbosacral radicular pain. We assessed perfusion index before treatment and at 5, 15, and 30 min following the block. We defined responders (group R) and non-responders (group N) as those with ≥50% and <50% pain reduction, respectively, 30 min following block. Clinical data and perfusion index of the groups were analyzed. Ninety-two patients were examined, of whom 57 (61.9%) and 35 (38.0%) patients reported ≥50% and <50% pain reduction, respectively. Group R had a significantly higher perfusion index change ratio 5 min following the block (p = 0.029). A perfusion index change ratio of ≥0.27 was observed in group R (sensitivity, 75.4%; specificity, 51.4%; AUC (area under the curve), 0.636; p = 0.032). A perfusion index change ratio of ≥0.27 at 5 min after block is associated with, but does not predict improvement in, pain levels following lumbosacral transforaminal block.

Effect of tranexamic acid on reducing postoperative blood loss in combined hypotensive epidural anesthesia and general anesthesia for total hip replacement.

STUDY OBJECTIVE: To determine whether the use of tranexamic acid in the setting of hypotension induced by hypotensive epidural anesthesia (HEA) has any additional beneficial effects in reducing perioperative blood loss and transfusion requirements in total hip replacement. DESIGN: Prospective, randomized, double-blinded trial. SETTING: University-affiliated hospital. PATIENTS: 68 adult, ASA physical status 1 and 2 patients undergoing primary unilateral cementless total hip replacement with general anesthesia and HEA. INTERVENTIONS: The HEATA group received a bolus dose of 15 mg/kg of tranexamic acid before surgical incision, followed by a continuous 15 mg/kg infusion until skin closure. The HEA group received normal saline instead of tranexamic acid in the same manner. MEASUREMENTS: Intraoperative blood loss was measured using the difference between the weights of used gauze and the original unused gauze, in addition to the blood volume accumulated in suction bottles. Postoperative blood loss was considered to be the amount of blood accumulated in drainage bags. MAIN RESULTS: There was no significant difference in intraoperative blood loss between the HEA and HEATA groups (251.8 ± 109.9 mL vs. 234.9 ± 93.9 mL), but postoperative blood loss was significantly less in the HEATA group than the HEA group (439.3 ± 171. 6 mL vs. 1074.4 ± 287.1 mL), as was total cumulative blood loss (674.2 ± 216.4 mL vs. 1326.2 ± 347.8 mL). There was no significant difference in intraoperative transfusion incidences, but postoperative transfusion was greater in the HEA group than the HEATA group. CONCLUSIONS: Administration of tranexamic acid combined with hypotensive epidural anesthesia reduced postoperative and total accumulative blood loss and transfusion requirements more than did hypotensive epidural anesthesia alone.