Comparison between the coronal diameters of the cervical spinal canal and spinal cord measured using computed tomography and magnetic resonance imaging in Korean patients / 대한마취과학회지

Background@#If the proportion of the spinal cord in the epidural space can be determined under C-arm fluoroscopy during cervical epidural block, a safe entry point for the epidural needle can be established. The aim of this study was the measurement of the cord to canal transverse diameter ratio of each cervical spines. @*Methods@#We retrospectively evaluated the imaging data of 100 patients who underwent both cervical computed tomography (CT) and cervical magnetic resonance imaging (MRI) at our hospital. We measured the diameters of the spinal canal and spinal cord from the 3rd cervical vertebra to the 1st thoracic vertebra (T1) at each level by using the patients’ cervical CT and MRI images. The spinal cord and spinal canal diameters were measured in the transverse plane of the cervical MRI and CT images, respectively. @*Results@#The spinal cord to spinal canal diameter ratio was the highest at the 4th and 5th cervical vertebrae (0.64 ± 0.07) and the lowest at T1 (0.55 ± 0.06, 99% CI [0.535, 0.565]. @*Conclusions@#Our findings suggest that the cord to canal transverse diameter ratio could be used as a reference to reduce direct spinal cord injuries during cervical epidural block under C-arm fluoroscopy. In the C-arm fluoroscopic image, if an imaginary line connecting the left and right innermost lines of the pedicles of T1 is drawn and if the needle is inserted into the outer one-fifth of the left and right sides, the risk of puncturing the spinal cord would be relatively reduced.

Effects of 10-min prewarming on core body temperature during gynecologic laparoscopic surgery under general anesthesia: a randomized controlled trial

Background@#Previous research has shown a beneficial effect of prewarming for preventing inadvertent perioperative hypothermia. However, there are few studies of the effects of a short prewarming period, especially in gynecologic laparoscopic surgery. @*Methods@#Fifty-four patients were randomly assigned to 2 groups. Patients in the non-prewarming group were only warmed intraoperatively with a forced air warming device, while those in the prewarming group were warmed for 10 min before anesthetic induction and during the surgery. The primary outcome was incidence of intraoperative hypothermia. @*Results@#Intraoperative hypothermia was observed in 73.1% of the patients in the non-prewarming group and 24% of the patients in the prewarming group (P < 0.001). There were significant differences in core temperature changes between the groups (P < 0.001). Postoperative shivering occurred in 8 of the 26 (30.8%) patients in the non-prewarming group and in 1 of the 25 (4.0%) patients in the prewarming group (P = 0.024). @*Conclusions@#Forced air warming for 10 min before induction on the operating table combined with intraoperative warming was an effective method to prevent hypothermia in patients undergoing gynecologic laparoscopic surgery.

Effects of small tidal volume and positive end-expiratory pressure on oxygenation in pressure-controlled ventilation-volume guaranteed mode during one-lung ventilation / 영남의대학술지

BACKGROUND@#The purpose of this study was to investigate whether tidal volume (TV) of 8 mL/kg without positive end-expiratory pressure (PEEP) and TV of 6 mL/kg with or without PEEP in pressure-controlled ventilation-volume guaranteed (PCV-VG) mode can maintain arterial oxygenation and decrease inspiratory airway pressure effectively during one-lung ventilation (OLV).@*METHODS@#The study enrolled 27 patients undergoing thoracic surgery. All patients were ventilated with PCV-VG mode. During OLV, patients were initially ventilated with TV 8 mL/kg (group TV8) without PEEP. Ventilation was subsequently changed to TV 6 mL/kg with PEEP (5 cmH₂O; group TV6+PEEP) or without (group TV6) in random sequence. Peak inspiratory pressure (P(peak)), mean airway pressure (P(mean)), and arterial blood gas analysis were measured 30 min after changing ventilator settings. Ventilation was then changed once more to add or eliminate PEEP (5 cmH₂O), while maintaining TV 6 mL/kg. Thirty min after changing ventilator settings, the same parameters were measured once more.@*RESULTS@#The P(peak) was significantly lower in group TV6 (19.3±.3 cmH₂O) than in group TV8 (21.8±3.1 cmH₂O) and group TV6+PEEP (20.1±3.4 cmH₂O). PaO₂ was significantly higher in group TV8 (242.5±111.4 mmHg) than in group TV6 (202.1±101.3 mmHg) (p=0.044). There was no significant difference in PaO₂ between group TV8 and group TV6+PEEP (226.8±121.1 mmHg). However, three patients in group TV6 were dropped from the study because PaO₂ was lower than 80 mmHg after ventilation.@*CONCLUSION@#It is postulated that TV 8 mL/kg without PEEP or TV 6 mL/kg with 5 cmH₂O PEEP in PCV-VG mode during OLV can safely maintain adequate oxygenation.

Effects of small tidal volume and positive end-expiratory pressure on oxygenation in pressure-controlled ventilation-volume guaranteed mode during one-lung ventilation / 영남의대학술지

BACKGROUND: The purpose of this study was to investigate whether tidal volume (TV) of 8 mL/kg without positive end-expiratory pressure (PEEP) and TV of 6 mL/kg with or without PEEP in pressure-controlled ventilation-volume guaranteed (PCV-VG) mode can maintain arterial oxygenation and decrease inspiratory airway pressure effectively during one-lung ventilation (OLV).METHODS: The study enrolled 27 patients undergoing thoracic surgery. All patients were ventilated with PCV-VG mode. During OLV, patients were initially ventilated with TV 8 mL/kg (group TV8) without PEEP. Ventilation was subsequently changed to TV 6 mL/kg with PEEP (5 cmH₂O; group TV6+PEEP) or without (group TV6) in random sequence. Peak inspiratory pressure (P(peak)), mean airway pressure (P(mean)), and arterial blood gas analysis were measured 30 min after changing ventilator settings. Ventilation was then changed once more to add or eliminate PEEP (5 cmH₂O), while maintaining TV 6 mL/kg. Thirty min after changing ventilator settings, the same parameters were measured once more.RESULTS: The P(peak) was significantly lower in group TV6 (19.3±.3 cmH₂O) than in group TV8 (21.8±3.1 cmH₂O) and group TV6+PEEP (20.1±3.4 cmH₂O). PaO₂ was significantly higher in group TV8 (242.5±111.4 mmHg) than in group TV6 (202.1±101.3 mmHg) (p=0.044). There was no significant difference in PaO₂ between group TV8 and group TV6+PEEP (226.8±121.1 mmHg). However, three patients in group TV6 were dropped from the study because PaO₂ was lower than 80 mmHg after ventilation.CONCLUSION: It is postulated that TV 8 mL/kg without PEEP or TV 6 mL/kg with 5 cmH₂O PEEP in PCV-VG mode during OLV can safely maintain adequate oxygenation.

The effect of nerve preservation methods on rat sciatic nerve structures studied with Synchrotron small-angle X-ray scattering (SAXS)

BACKGROUND: Synchrotron small-angle X-ray scattering (SAXS) is a very useful technique for experimental study of the nano-structure of the nervous system of animals. The study was designed to evaluate nerve preservation methods for the measurement of SAXS patterns. METHODS: Normal sciatic nerves extracted from male Sprague- Dawley rats were preserved in saline (N = 2), formalin (N = 2) or liquid nitrogen (N = 2) for 1 day, followed by measurement of SAXS patterns. SAXS patterns of normal sciatic nerves (N = 3) extracted just before the initiation of the experiment were used as controls. The study was carried out using the 4C1 beamline at Pohang Accelerator Laboratory in Korea. Incoming X-rays were monochromatized at 11 keV using a double multilayer (WB4C) monochromator with beam size of approximately 0.5 (V) × 0.8 (H) mm2. The exposure time was set at 60 sec, and 8 to 12 images per sample were acquired at a 0.5 mm interval. RESULTS: The periodic peaks of interfibrillar space between collagen fibrils were undetectable. The periodic peaks of the myelin sheath and collagen fibers were weakly detected or undetected in the nerves preserved in normal saline or formalin. The periodic peaks and intensity of the myelin sheath, collagen fibers, and interfibrillar space between collagens in the nerves preserved in liquid nitrogen were comparable to those of nerves in the ex vivo state. CONCLUSIONS: The study results indicated that preservation of nerves in liquid nitrogen is adequate for measurements with SAXS. However, saline and formalin preservation techniques were inadequate for SAXS measurement.

Structural analysis of a ligatured rat sciatic nerve in the ex vivo state using synchrotron small-angle X-ray scattering (SAXS)

BACKGROUND: To understand the fundamentals of neural tissue injury, experiments on the nano-structured nerve system of animals are essential. This study was designed to reveal the nanostructure changes of an isolated ligatured rat sciatic nerve using the synchrotron small-angle X-ray scattering (SAXS) technique. METHODS: Male Sprague-Dawley rats (weighing approximately 250 grams) were used in this study. The SAXS patterns of 1 week after ligatured nerves (N = 5) and the normal sciatic nerves (N = 5) for the control were acquired after extracted approximately 15 mm before the experiment. Experiments were conducted at the 4C1 beam line at the Pohang Accelerator Laboratory in Korea. The exposure time was 60 sec, and 8 to 12 images per sample were acquired in 0.5 mm intervals, including the regions above, around and below the ligatured position. RESULTS: The periodic peaks of the myelin sheath and the interfibrillar space of collagen completely disappeared at the ligatured position. Farther from the ligatured point, weak and quite different SAXS patterns were observed for the myelin sheath and interfibrillar space. However, the collagen fiber peaks appeared at all positions, although they were weaker near the ligatured position. CONCLUSIONS: The ligature treatment totally destroyed the myelin sheath and interfibrillar space of collagen. In addition, retrograde degeneration developed 2 mm above the ligatured site. The myelin sheath and interfibrillar space of collagen were damaged 6 mm below the ligatured site. However, the collagen fiber structure was not significantly affected by the ligature, indicating a much different structural organization.

Airway management of patients with traumatic brain injury/C-spine injury / 대한마취과학회지

Traumatic brain injury (TBI) is usually combined with cervical spine (C-spine) injury. The possibility of C-spine injury is always considered when performing endotracheal intubation in these patients. Rapid sequence intubation is recommended with adequate sedative or analgesics and a muscle relaxant to prevent an increase in intracranial pressure during intubation in TBI patients. Normocapnia and mild hyperoxemia should be maintained to prevent secondary brain injury. The manual-in-line-stabilization (MILS) technique effectively lessens C-spine movement during intubation. However, the MILS technique can reduce mouth opening and lead to a poor laryngoscopic view. The newly introduced video laryngoscope can manage these problems. The AirWay Scope(R) (AWS) and AirTraq laryngoscope decreased the extension movement of C-spines at the occiput-C1 and C2-C4 levels, improving intubation conditions and shortening the time to complete tracheal intubation compared with a direct laryngoscope. The Glidescope(R) also decreased cervical movement in the C2-C5 levels during intubation and improved vocal cord visualization, but a longer duration was required to complete intubation compared with other devices. A lightwand also reduced cervical motion across all segments. A fiberoptic bronchoscope-guided nasal intubation is the best method to reduce cervical movement, but a skilled operator is required. In conclusion, a video laryngoscope assists airway management in TBI patients with C-spine injury.

Analysis of ultrastructural changes in the rat sciatic nerve after exposure to pulsed radiofrequency using small angle X-ray scattering (SAXS)

BACKGROUND: Pulsed radiofrequency (PRF) may be used in the treatment of patients with some pain syndromes that cannot be controlled by alternative techniques. The objective of the present study is to examine the ultrastructural changes in rat sciatic nerve after PRF, using synchrotron small angle X-ray scattering (SAXS). METHODS: Twenty rats (Male Sprague-Dawley, about 250 grams) were used this study. The PRF is applied to the afferent axons of the sciatic nerves of the rats in ex vivo state, and the ultrastructure of axons were studied after 1 (N = 5), 4 (N = 5), and 6 (N = 5) weeks by SAXS. The control (N = 5) consisted of non-treated sciatic nerve to provide a statistical differential comparison. RESULTS: In the PRF group, the periodic peaks of myelin sheath and collagen fibrils were not changed compared to the control group, in the time progression of 1, 4, and 6 weeks. But the periodic peaks of interfibrillar distance of collagen were greater at 1 and 4 weeks after PRF, comparing to the control group, but it had tendency to return to normal in 6 weeks. CONCLUSIONS: It is suggested that PRF did not induce ultrastructural change of myelin sheath and collagen fiber, but it induced the change of distance between collagen fibrils of the nerve tissue. This change was not caused by thermal injury but by electromagnetic fields and it is reversible.

Volume-controlled versus pressure-controlled ventilation-volume guaranteed mode during one-lung ventilation / 대한마취과학회지

BACKGROUND: The purpose of this study was to investigate the changes in airway pressure and arterial oxygenation between ventilation modes during one-lung ventilation (OLV) in patients undergoing thoracic surgery. METHODS: We enrolled 27 patients for thoracic surgery with OLV in the lateral decubitus position. The subjects received various modes of ventilation in random sequences during surgery, including volume-controlled ventilation (VCV) and pressure-controlled ventilation-volume guaranteed (PCV-VG) with a tidal volume (TV) of 8 ml/kg of actual body weight. Target-controlled infusion (TCI) with propofol and remifentanil was used for anesthesia induction and maintenance. After double-lumen endobronchial tube (DLT) insertion, the proper positioning of the DLT was assessed using a fiberoptic bronchoscope. Peak inspiratory pressure (Ppeak), exhaled TV, and arterial blood gas were measured 30 min after each ventilation mode. RESULTS: P(peak) was significantly reduced with the PCV-VG mode (19.6 +/- 2.5 cmH2O) compared with the VCV mode (23.2 +/- 3.1 cmH2O) (P < 0.000). However, no difference in arterial oxygen tension was noted between the groups (PCV-VG, 375.8 +/- 145.1 mmHg; VCV, 328.1 +/- 123.7 mmHg) (P = 0.063). The exhaled TV was also significantly increased in PCV-VG compared with VCV (451.4 +/- 85.4 vs. 443.9 +/- 85.9 ml; P = 0.035). CONCLUSIONS: During OLV in patients with normal lung function, although PCV-VG did not provide significantly improved arterial oxygen tension compared with VCV, PCV-VG provided significantly attenuated airway pressure despite significantly increased exhaled TV compared with VCV.

Volume-controlled versus pressure-controlled ventilation-volume guaranteed mode during one-lung ventilation / 대한마취과학회지

BACKGROUND: The purpose of this study was to investigate the changes in airway pressure and arterial oxygenation between ventilation modes during one-lung ventilation (OLV) in patients undergoing thoracic surgery. METHODS: We enrolled 27 patients for thoracic surgery with OLV in the lateral decubitus position. The subjects received various modes of ventilation in random sequences during surgery, including volume-controlled ventilation (VCV) and pressure-controlled ventilation-volume guaranteed (PCV-VG) with a tidal volume (TV) of 8 ml/kg of actual body weight. Target-controlled infusion (TCI) with propofol and remifentanil was used for anesthesia induction and maintenance. After double-lumen endobronchial tube (DLT) insertion, the proper positioning of the DLT was assessed using a fiberoptic bronchoscope. Peak inspiratory pressure (Ppeak), exhaled TV, and arterial blood gas were measured 30 min after each ventilation mode. RESULTS: P(peak) was significantly reduced with the PCV-VG mode (19.6 +/- 2.5 cmH2O) compared with the VCV mode (23.2 +/- 3.1 cmH2O) (P < 0.000). However, no difference in arterial oxygen tension was noted between the groups (PCV-VG, 375.8 +/- 145.1 mmHg; VCV, 328.1 +/- 123.7 mmHg) (P = 0.063). The exhaled TV was also significantly increased in PCV-VG compared with VCV (451.4 +/- 85.4 vs. 443.9 +/- 85.9 ml; P = 0.035). CONCLUSIONS: During OLV in patients with normal lung function, although PCV-VG did not provide significantly improved arterial oxygen tension compared with VCV, PCV-VG provided significantly attenuated airway pressure despite significantly increased exhaled TV compared with VCV.

Gastrectomy for the treatment of refractory gastric ulceration after radioembolization with 90Y microspheres

Transcatheter arterial radioembolization (TARE) with Yttrium-90 (90Y)-labeled microspheres has an emerging role in treatment of patients with unresectable hepatocellular carcinoma. Although complication of TARE can be minimized by aggressive pre-evaluation angiography and preventive coiling of aberrant vessels, radioembolization-induced gastroduodenal ulcer can be irreversible and can be life-threatening. Treatment of radioembolization-induced gastric ulcer is challenging because there is a few reported cases and no consensus for management. We report a case of severe gastric ulceration with bleeding that eventually required surgery due to aberrant deposition of microspheres after TARE.

Re-evaluation of the applicability of ketamine in neurosurgical anesthesia

Traditionally, Ketamine has been considered to be contraindicated in neurosurgical patients due to the risk of intracranial hypertension. The evidence for this contraindication originated from early case reports and case-control studies which were inadequately designed and controlled. However, several recent articles indicate that ketamine can be safely used in traumatic brain injured patients treated with mechanical ventilation and that there is no significant increase in the intracranial pressure (ICP). Ketamine is an N-methyl-D-aspartate antagonist. It is believed to provide neuroprotection through a reduction in the glutamate excitotoxicity. This evidence is based on in vitro and animal studies. However, studies about its neuroprotective effects in humans are scarce. Data to recommend ketamine as first-line anesthetics for neurosurgery are insufficient, but ketamine as an adjuvant anesthetic agent may have benefits for neurosurgical patients, such as traumatic head injured patients with unstable hemodynamics. Therefore, ketamine should not be considered as absolutely contraindicated for neurosurgical patients and adequately powered, high-quality randomized controlled studies are needed to provide clinical evidences.

Peripheral nerve injury caused by needle impalement: Synchrotron small-angle X-ray scattering study in ex-vivo rat sciatic nerve

BACKGROUND: Direct puncture by a needle is a risk factor for nerve damage. This study was designed to demonstrate nerve damage caused by a needle using the synchrotron small-angle X-ray scattering (SAXS) technique. METHODS: A 15 mm section of rat (Male Spargue-Dawley, about 250 grams) sciatic nerves were involved in this study. The nerve specimen for the experiment (N = 5) was punctured 5 times by a needle (25 G, 100 beveled) under general anesthesia with enflurane. The needle was placed perpendicular to the nerve and the needle bevel was placed parallel to the nerve. The SAXS patterns of the punctured nerves, extracted about 15 min prior to the experiment, were acquired after 1 week. The SAXS patterns of a normal sciatic nerve (N = 5), extracted about 15 min prior to the experiment, were measured in order to provide a comparison. Experiments were carried out at 4C1 beamline at Pohang Accelerator Laboratory in Korea. Incoming X-rays were monochromatized at 11 keV using a double multilayer (WB4C) monochromator; the beam size was around 0.5 (V) x 0.8 (H) mm2. The exposure time was 60 sec, and 8 to 12 images were acquired per sample with a 0.5 mm interval. RESULTS: In the punctured group, the periodic peaks of myelin sheath and collagen fiber were not changed. However, the periodic peaks of interfibrillar distance of collagen were greatly changed. CONCLUSIONS: Direct needle-nerve impalement did not cause damages in myelin sheath and collagen fibers when the needle was placed perpendicular and the needle bevel paralleled to the nerve fiber. This result can imply that the needle slipped into the interfibrillar packing of collagen fibrils.

Intraoperative Fluid Management in Combined Liver-Kidney Transplantation / 대한구급학회지

A review of the literature regarding combined liver-kidney transplantation (CLKT) does not provide adequate central venous pressure (CVP) values that would allow for unimpaired hepatic venous outflow and early renal allograft diuresis during the procedure. We report a case of fluid management of CLKT based on the limited literature available in a 59-year-old male with liver cirrhosis and end-stage renal disease. During the preanhepatic phase, CVP was maintained at 5 mmHg. Following portal vein clamping, CVP was reduced to below 5 mmHg until venovenous bypass was initiated. From the neohepatic phase to 1 hour before renal allograft reperfusion, CVP was slowly increased to 10 mmHg. Within an hour before renal allograft reperfusion, maximal crystalloid hydration was used to increase CVP to 15 mmHg. The urine output was replaced to maintain CVP at 8 to 10 mmHg until the end of the surgery. The postoperative course was uneventful. In conclusion, fluid management tailored to each phase yielded beneficial results in a patient with CLKT.

Continuous Intrathecal Morphine Administration for Cancer Pain Management Using an Intrathecal Catheter Connected to a Subcutaneous Injection Port: A Retrospective Analysis of 22 Terminal Cancer Patients in Korean Population

BACKGROUND: Intrathecal opioid administration has been used widely in patients suffering from severe cancer pain that is not managed with conventional modalities. However, the potential serious neurological complications from the procedure and the side effects of intrathecal opioids have made many clinicians reluctant to employ continuous intrathecal analgesia as a first-line therapeutic option despite its dramatic effect on intractable pain. We retrospectively investigated the efficacy, side effects, and complications of intrathecal morphine administration through intrathecal catheters connected to a subcutaneous injection port (ICSP) in 22 Korean terminal cancer patients with successful intrathecal morphine trials. METHODS: Patient demographic data, the duration of intrathecal opioid administration, preoperative numerical pain rating scales (NRS) and doses of systemic opioids, side effects and complications related to intrathecal opioids and the procedure, and the numerical pain rating scales and doses of intrathecal and systemic opioids on the 1st, 3rd, 7th and 30th postoperative days were determined from medical records. RESULTS: Intrathecal morphine administration for 46.0 +/- 61.3 days significantly reduced NRS from baseline on all the postoperative days. A significant increase in intrathecal opioids with a nonsignificant decrease in systemic opioids was observed on the 7th and 30th postoperative days compared to the 1st postoperative day. The most common side effects of intrathecal opioids were nausea/vomiting (31.8%) and urinary retention (38.9%), which were managed with conservative therapies. CONCLUSIONS: Intrathecal morphine administration using ICSP provided immediate and beneficial effects on pain scores with tolerable side effects in terminal cancer patients.

Bispectral index monitoring correlates with the level of consciousness in brain injured patients / 대한마취과학회지

BACKGROUND: In general, measuring the level of consciousness in neurological patients is important. To assess the patient's mental status, the Glasgow Coma Scale (GCS) and the level of consciousness (drowsiness, stupor, and coma) have been used in clinical situations. The aim of the present study was to identify the correlation between bispectral index (BIS) and level of consciousness in brain injured patients. METHODS: Eighty-nine adult patients of both sexes were included in the study. A blinded observer evaluated the mental status (GCS and level of consciousness) of a patient who is admitted in intensive care unit with brain injury, while an investigator noted the patient's BIS. The BIS was measured using a BIS monitor, Model A-3000 vista(TM) with Sensor Bis quatro(TM) (Aspect Medical Systems, Norwood, USA). A Spearman's rank correlation coefficient was used to determine if the level of consciousness correlated with the BIS. RESULTS: In 89 patients, the BIS was found to be significantly correlated with the level of consciousness (r = 0.723, P < 0.01) and GCS (r = 0.646, P < 0.01). The BIS values increased with an increasing level of consciousness. Mean BIS values of coma, semicoma, stupor and drowsiness were 0.14 +/- 0.23, 38.9 +/- 18.0, 60.3 +/- 14.5, and 73.6 +/- 16.5, respectively. CONCLUSIONS: In the present study, a significant correlation existed between level of consciousness and BIS. These findings suggest that BIS may be used for assessing the level of consciousness in brain injured patients. However, the scatter of BIS values for any level of consciousness limited the worth of BIS in predicting mentality except in coma patients.

Usefulness of the bispectral index during cardiopulmonary resuscitation: A case report / 대한마취과학회지

The usefulness of using the bispectral index (BIS) for monitoring during cardiopulmonary resuscitation (CPR) is not clearly understood. However, BIS has been a popular anesthetic monitoring device used during operations. The case presented is of a pregnant woman going into cardiac arrest due to an amniotic fluid embolism during a Cesarean section. CPR was performed, but neither the return of spontaneous circulation (ROSC) nor the return of consciousness was achieved, despite 50 min of effective CPR. However, CPR was continued based on BIS. ROSC was achieved, and an alert consciousness state was reached 1 day postoperation. This finding suggests that BIS be used as a basic monitoring device during CPR and that it may help in deciding to continue CPR.

Effects of intraoperative continuous infusion of low dose remifentanil and intravenous bolus dose of fentanyl on postoperative pain

BACKGROUND: The aim of this study was to evaluate whether continuous infusion of remifentanil during propofol anesthesia could produce opioid-induced hyperalgesia (OIH) and whether an intravenous bolus of fentanyl could control OIH in the management of postoperative pain. METHODS: One hundred fifty-nine women undergoing gynecologic surgery were randomly divided into four groups. Group C: nitrous oxide and propofol infusion (3-4 microg/ml, n = 40), Group F: propofol infusion and intravenous bolus administration of fentanyl (1 microg/kg) after suturing the peritoneum (n = 40), Group R: propofol and remifentanil infusion (2-4 ng/ml, n = 40) and Group RF: propofol, remifentanil infusion and intravenous bolus administration of fentanyl (n = 39). Patient controlled analgesia was started after the operation. The postoperative visual analog scale (VAS) was measured in the recovery room, then at 2 h, 6 h, 12 h, and 24 h after the operation. RESULTS: The VAS scores for Groups R and F in the recovery room were lower than for group C (P < 0.05), but there were no differences 2 h after the operation. The VAS scores for Group RF 6 h and 12 h after the operation were higher than those for group C (P < 0.05). CONCLUSIONS: Our results suggest that low dose (2-4 ng/ml) continuous infusion of remifentanil during propofol anesthesia does not produce marked hyperalgesia. However, an intravenous bolus of fentanyl can aggravate OIH induced by remifentanil.

Effects of intraoperative continuous infusion of low dose remifentanil and intravenous bolus dose of fentanyl on postoperative pain

BACKGROUND: The aim of this study was to evaluate whether continuous infusion of remifentanil during propofol anesthesia could produce opioid-induced hyperalgesia (OIH) and whether an intravenous bolus of fentanyl could control OIH in the management of postoperative pain. METHODS: One hundred fifty-nine women undergoing gynecologic surgery were randomly divided into four groups. Group C: nitrous oxide and propofol infusion (3-4 microg/ml, n = 40), Group F: propofol infusion and intravenous bolus administration of fentanyl (1 microg/kg) after suturing the peritoneum (n = 40), Group R: propofol and remifentanil infusion (2-4 ng/ml, n = 40) and Group RF: propofol, remifentanil infusion and intravenous bolus administration of fentanyl (n = 39). Patient controlled analgesia was started after the operation. The postoperative visual analog scale (VAS) was measured in the recovery room, then at 2 h, 6 h, 12 h, and 24 h after the operation. RESULTS: The VAS scores for Groups R and F in the recovery room were lower than for group C (P < 0.05), but there were no differences 2 h after the operation. The VAS scores for Group RF 6 h and 12 h after the operation were higher than those for group C (P < 0.05). CONCLUSIONS: Our results suggest that low dose (2-4 ng/ml) continuous infusion of remifentanil during propofol anesthesia does not produce marked hyperalgesia. However, an intravenous bolus of fentanyl can aggravate OIH induced by remifentanil.

Femoral and sciatic nerve blocks for total knee replacement in an obese patient with a previous history of failed endotracheal intubation: A case report

Peripheral nerve block has frequently been used as an alternative to epidural analgesia for postoperative pain control in patients undergoing total knee replacement. However, there are few reports demonstrating that the combination of femoral and sciatic nerve blocks (FSNBs) can provide adequate analgesia and muscle relaxation during total knee replacement. We experienced a case of successful FSNBs for a total knee replacement in a 66 year-old female patient who had a previous cancelled surgery due to a failed tracheal intubation followed by a difficult mask ventilation for 50 minutes, 3 days before these blocks. FSNBs were performed with 50 ml of 1.5% mepivacaine because she had conditions precluding neuraxial blocks including a long distance from the skin to the epidural space related to a high body mass index and nonpalpable lumbar spinous processes. This case suggests that FSNBs can provide a good alternative anesthetic method for total knee replacement.