Localization of the genicular arteries under ultrasound guidance

BACKGROUND: The genicular arteries (GAs) can be utilized for genicular nerve block. We aimed to evaluate the ability to localize GAs under ultrasound in patients with chronic knee pain. METHODS: Twenty-four knees from 14 osteoarthritic patients were enrolled. The target GAs included the superomedial GA (SMGA), superolateral GA (SLGA), and inferomedial GA (IMGA). GAs were observed at the relevant adductor tubercle and epicondyle-shaft transition under ultrasound. Distribution of the SMGA at the adductor tubercle was evaluated using defined zones in transverse and longitudinal ultrasound images. SLGA and IMGA were also categorized using defined zones in longitudinal images. Distance from bony cortex to the relevant GA was then estimated. RESULTS: Among 24 knees, 91.7% of SMGAs were located at the upper part of the adductor tubercle. The distances between the SMGA and bony cortex on transverse view (dSMGAt) and on longitudinal view (dSMGAl) were directly correlated (rs = 0.6539, P = 0.0005). CONCLUSIONS: Under ultrasound guidance, the SMGA was found to be mainly localized to the upper part of the adductor tubercle. Likewise, the SLGA and IMGA were mainly localized at the distal and proximal parts of the epicondyle-shaft transition, respectively. Our results support the feasibility of ultrasound guidance for GA localization in patients with knee osteoarthritis.

Use of high-frequency oscillatory ventilation with inhaled nitric oxide in congenital diaphragmatic hernia, omphalocele, and patent ductus arteriosus / 대한마취과학회지

No abstract available.

Fluoroscopic analysis of lumbar epidural contrast spread after retrograde interlaminar ventral epidural injection (RIVEI) / 대한마취과학회지

BACKGROUND: Retrograde interlaminar ventral epidural injection (RIVEI) may hypothetically be more effective if the catheter is placed at the ventrocaudal aspect of the exiting nerve. We tested that hypothesis by measuring ventral and dorsal epidural contrast flow during RIVEI. METHODS: To perform RIVEI, a 17 G Tuohy needle was inserted to access the epidural space. A 19 G epidural catheter was inserted and advanced through the needle, passing in a caudal direction to the lower aspect of the contralateral pedicle. Fluoroscopic images were recorded at 1.5 ml increments of contrast. Based on the images of contrast dispersal, the extent of contrast spreading was assessed in 82 patients. RESULTS: All 82 patients (100%) injected with 3.0 ml contrast medium demonstrated ventral epidural spreading. Mean spreading level from the catheter tip was 2.21 +/- 0.93 with 3.0 ml of contrast. Spreading to the superior aspect of the supra-adjacent intervertebral disc was observed in 67/82 (81.7%) of RIVEIs with 3.0 ml of contrast injected into the ventral epidural space. We found that 3.0 ml of contrast reached the inferior aspect of the infra-adjacent intervertebral disc in 95.1% (78/82) of RIVEIs performed. CONCLUSIONS: Our findings imply that a one-level RIVEI may be sufficient in situations where a two-level injection would currently be used.

Epidural contrast flow patterns of retrograde interlaminar ventral epidural injections stratified by the final catheter tip placement

BACKGROUND: The aim of the study is to evaluate the relevant spreading for contrasts in the ventral and dorsal epidural space during retrograde interlaminar ventral epidural injections (RIVEIs) with the catheter tip placed ventral or dorsal to the spinal nerve. METHODS: For RIVEIs, a 17G Tuohy needle was inserted in retrograde fashion. Catheter containing a removable stylet was inserted and advanced via the needle and passed to the lower aspect of contralateral pedicles in 75 patients. Fluoroscopic images were recorded at 1.5 ml increments of contrast. Using the fluoroscopy, the contrast spreading pattern and whether the contrast spread to the specific anatomic landmarks (superior aspect of the supra-adjacent intervertebral disc [SIVD] and inferior aspect of the infra-adjacent intervertebral disc [IIVD]) were evaluated. Whether the catheter was placed ventral or dorsal to the spinal nerve was assessed with the computed tomography axial and sagittal views. RESULTS: There were no significant differences in the mean levels of epidural contrast spreading extents between ventral and dorsal catheter placements. Ventral or dorsal catheter tip placements demonstrated ventral concurrent flows over to the SIVD and IIVD over 80% of subjects with 3.0 ml of contrast. CONCLUSIONS: During RIVEIs, the catheter tip placed ventral to the spinal nerve did not show superiority with regards to epidural spreading extent as compared with dorsal catheter placement. One-level instead of a two-level injection may be considered for the two-level central pathology.

Electrical stimulation of the epiradicular space using a catheter with a removable stylet

BACKGROUND: Electrical stimulation can be used to verify the location of epidural catheters. Although epiradicular localization of a catheter is important for patients with radiating pain in the lower extremities due to spinal stenosis or disc herniation, no prospective study results pertaining to the stimulation threshold within the epiradicular space have been reported. Therefore, we set out to investigate the threshold current for motor response in the epiradicular space by the use of a catheter containing a removable stylet. In addition, this study examines the reliability of such epiradicular stimulation. METHODS: In 105 patients undergoing a retrograde interlaminar ventral epidural injection, a lumbar epiradicular catheter was inserted. Loss of resistance was used to identify the epidural space. Afterward, the TheraCath was advanced into the epiradicular space and connected to a nerve stimulator. A nerve stimulator delivered progressively, increasing electrical current until an appropriate muscle contraction was observed. Contrast media was then injected and epiradicular dispersal was assessed. RESULTS: Epiradicular stimulation yielded a mean threshold of 0.56 +/- 0.50 mA (range: 0.06 to 2.84). When compared with epiradicular dispersal as a gold standard, the sensitivity, specificity, positive predictive value, and negative predictive value of epiradicular stimulation with the TheraCath were 90%, 56%, 96% and 33%, respectively. CONCLUSIONS: The threshold current of an insulated needle required to elicit a motor response in the epiradicular space was evaluated. We conclude that the epiradicular stimulation test is useful for confirming catheter placement. Nonetheless, further studies are required before implementing its routine use in clinical settings.

Minimum current requirement for confirming the localization of an epiradicular catheter placement / 대한마취과학회지

BACKGROUND: Based on the necessity to confirm the epiradicular catheter misplacement, epiradicular threshold current for the confirmation of catheter tip localization is required. METHODS: Thirty-four adult patients with low extremity radiating pain were to receive epiradicular catheterization at the lumbosacral level. The epidural space was accessed percutaneously in cranial to caudal direction. A metal coil-reinforced epidural catheter was inserted and advanced caudolaterally toward the target neural foramen until the catheter tip was located below the bisection of pedicle. The electrical stimulation was performed after catheter placement in epidural and epiradicular space. Using the constant current nerve stimulator, the stimulating current was increased from 0 to 5 mA (pulse width of 0.3 ms; frequency of 2 Hz) until adequate motor contraction was evident. The threshold current for motor response with epidural space (EDmA) and epiradicular space (ERmA) placement were recorded upon electrical stimulation. In addition, the threshold charge for motor response with epidural (EDnC) and epiradicular (ERnC) placement were recorded. RESULTS: Of 34 catheters intentionally placed in the epiradicular space, ERmA was 0.53 +/- 0.48 mA. The ERnC was significantly lower than EDnC (P < 0.05). The EDmA and ERmA were below 1 mA in 3 patients and above 1 mA in 4 patients, respectively. CONCLUSIONS: We conclude that, threshold current for motor response seems to be lower for epiradicular compared with epidural placement, although we were not able to directly investigate the epidural threshold current. The threshold current of epiradicular space overlap that in the epidural space.

Ultrasound-guided greater occipital nerve block for patients with occipital headache and short term follow up / 대한마취과학회지

BACKGROUND: The greater occipital nerve (GON) block has been frequently used for different types of headache, but performed with rough estimates of anatomic landmarks. Our study presents the values of the anatomic parameters and estimates the effectiveness of the ultrasound-guided GON blockade. METHODS: The GON was detected using ultrasound technique and distance from external occipital protuberance (EOP) to GON, from GON to occipital artery and depth from skin to GON was measured in volunteers. Patients with occipital headache were divided into two groups (ultrasound-guided block: group S, conventional blind block: group B) and GON block was performed. The same parameters were measured on group S and VAS scores were assessed at pretreatment, 1 week and 4 weeks after treatment on both groups. RESULTS: The GON had distance of 23.1 +/- 3.4 mm (right) and 20.5 +/- 2.8 mm (left) from EOP to GON. Its depth below the skin was 6.8 +/- 1.5 mm (right) and 7.0 +/- 1.3 mm (left). The distance from GON to occipital artery was 1.5 +/- 0.6 mm (right) and 1.2 +/- 0.6 mm (left) in volunteers. Initial VAS score of group S and group B patients were 6.4 +/- 0.2 and 6.5 +/- 0.2. VAS score of 4 weeks after injection were 2.3 +/- 0.2 on group S and 3.8 +/- 0.3 on group B (P = 0.0003). CONCLUSIONS: The parameters measured in this study should be useful for GON block and ultrasound-guided blockade is likely to be a more effective technique than blind blockade in occipital headache treatment.

Lumbar Ventral Epidural Approach / 한양의대학술지

The utilization of transforaminal epidural steroid injections (TFESIs), an elective diagnostic and therapeutic spinal procedure, has risen dramatically over the past decade. The transforaminal technique uses a needle that approaches the posterolateral aspect of the intervertebral foramen. Despite the superiority of the transforaminal route, transforaminal blocks have been associated with devastating neurological complications, particularly paraplegia. Since the radiological target advocated for transforaminal injections matches the superoanterior portion of the foramen, it comes as no surprise that this approach renders radiculomedullary arteries vulnerable to injury. The author uses retrograde interlaminar ventral epidural steroid injection with catheters to obtain a theoretically advantageous placement of epidural corticosteroid. Epidurography of such injections does demonstrate that this approach more frequently achieves coverage of both the putative disc source of nerve irritation and of the affected segmental nerve.

Correlation between actual measurement and estimation by hemoglobin dilution method

BACKGROUND: Hemoglobin dilution occurs after acute blood loss, by shifting extravascular blood components into the intravascular space, providing the theoretical possible to calculate amount of blood loss by comparing this difference.Assessing blood loss during the operative procedure is crucial to provide appropriate treatment, however there are few objective standards by which to make this assessment.In this study, we used the hemoglobin dilution method to predict blood loss following an operative procedure. METHODS: During the year 2007, 96 patients who had undergone lumbar spinal fusion surgery were enrolled in this study.On a retrospective basis, we investigated the weight, height, intraoperative blood loss, hemoglobin change, and the amount of transfused erythrocytes by reviewing anesthetic notes from the surgery. On the basis of these data, we calculated estimated blood loss by using Nadler's formula. RESULTS: The majority of study participants were female and average age was 60.1 yrs.We observed 2.3 g/dl decrement of postoperative hemoglobin, and estimated blood volume was 3,599 ml. Estimated blood loss was 853.7 ml, and observed blood loss was 1,070 ml, thus creating 217.1 ml difference.Analysis showed a moderate degree of correlation between observed and estimated values and a correlation coefficient of 0.49. We obtained regression equations of y = 0.828x + 363.5. CONCLUSIONS: Estimated blood loss was underestimated compared to observed values, by 20%, and this discrepancy is was attributed to ethnic differences. To predict a precise estimated blood loss, attempts to make a modified formula targeted to the Korean population are required.

Incidence of Intravascular Penetration during Transforaminal Lumbosacral Epidural Steroid Injection / 대한통증학회지

BACKGROUND: Epidural steroid injections (ESI) are a common treatment for spinal disorders. Previous research has shown that aspiration of the syringe is not a sensitive test for placement of an intravascular needle. Serious complications have been reported from injection of steroids and local anesthetics into the vascular space. In addition to safety concerns, the efficacy may decline with partial injection outside the desired epidural location. We hypothesized that incidence of vascular problems is increased in patients who undergo spine surgery compared with the patients who don't undergo spine surgery. We investigated the incidence of vascular problems during lumbosacral transforaminal ESI and we compared the difference of vascular problems between the patients who undergo spinal surgery and those patients who don't undergo spinal surgery. METHODS: Two hundreds and three patients were consecutively recruited and they received 299 fluoroscopically guided lumbosacral transforaminal ESIs. Injection of contrast was performed under live dynamic fluoroscopy with using digital substraction analysis. The observed uptake pattern was classified into one of three categories: flashback, aspirated, and positive contrast with negative flashback and aspiration. RESULTS: The vascular incidence rate was 20.4%. Transforaminal ESIs performed at S1 had avascular incidence rate of 27.8% compared with 17.7% for all the other lumbar injection sites. The sensitivity of spontaneous observation of blood in the needle hub or blood aspirate for predicting an intravascular injection in lumbar transforaminal ESIs was 70.4%. CONCLUSIONS: There is a high incidence of intravascular problems when performing transforaminal ESIs, and this is significantly increased in patients with previous spine surgery. Using a flash or blood aspiration to predict an intravascular injection is not sensitive therefore; a negative flash or aspiration is not reliable. Fluoroscopically guided procedures without contrast confirmation are prone to instill medications intravascularly. This finding confirms the need for not only fluoroscopic guidance, but also for contrast injection instillation when performing lumbosacral transforaminal ESIs, and especially for patients with previous spine surgery.

Cervical and Thoracic Spinal Cord Stimulation in a Patient with Pediatric Complex Regional Pain Syndrome: A case report / 대한통증학회지

Complex Regional Pain Syndromes (CRPS) type I and type II are neuropathic pain conditions that are being increasingly recognized in children and adolescents. The special distinctive features of pediatric CRPS are the milder course, the better response to treatment and the higher recurrence rate than that of adults and the lower extremity is commonly affected. We report here on a case of pediatric CRPS that was derived from ankle trauma and long term splint application at the left ankle. The final diagnoses were CRPS type I in the right upper limb, CRPS type II in the left lower limb and unclassified neuropathy in the head, neck and precordium. The results of various treatments such as medication, physical therapy and nerve blocks, including lumbar sympathetic ganglion blocks, were not effective, so implantation of a spinal cord stimulator was performed. In order to control the pain in his left lower limb, one electrode tip was located at the 7th thoracic vertebral level and two electrode tips were located at the 7th and 2nd cervical vertebral levels for pain control in right upper limb, head, neck and right precordium. After the permanent insertion of the stimulator, the patient's pain was significantly resolved and his disabilities were restored without recurrence. The patient's pain worsened irregularly, which might have been caused by psychological stress. But the patient has been treated with medicine at our pain clinic and he is being followed up by a psychiatrist.

Interventional Treatment for Cervical Pain

Radiofrequency current is simply a tool used to create discrete thermal lesions in neural pathways in order to interrupt transmission. In pain medicine, radiofrequency lesions have been used to interrupt nociceptive pathways at various sites. This is a palliative treatment accompanying complications, so its use should be limited to those patients with cancer pain or chronic non-cancer pain when conservative non-surgical therapies have proven to be ineffective or intoerable. With the development of alternatives such as intrathecal opioid infusion and neuromodulation technologies, the number of patients considered for neuroablative therapy may dwindle. Nevertheless, there is a line of evidence that radiofrequency neurotomy has an important role in the management of trigeminal neuralgia, nerve root avulsion and spinal pain. This article introduces the radiofrequency lesioning as an interventional treatment modality of cervical pain.

Third Occipital Nerve Radiofrequency Neurotomy with Radiologic Open Mouth View: A case report / 대한통증학회지

Radiofrequency lesioning is a valuable tool for third occipital headache. Relative to most neural targets, a radiofrequency lesion is very small. Reliable pre-operative diagnosis of the nociceptive source is critical, as inappropriately placed lesions will not modulate pain. Knowledge of the anatomical courses of nerves and extremely precise electrode placement are required for accurate lesioning. This report describes our experience with RF lesioning in the treatment of chronic pain in two patients who suffered from third occipital headaches. In one patient, satisfactory improvement of the pain was observed after 10 months of follow up.

Burn Wound along the Guide Needle Trajectory as a Complication of Radiofrequency Neurotomy of the Lumbar Medial Branch: A case report / 대한통증학회지

Radiofrequency neurotomy of the lumbar medial branch, via a caudal approach, is a representative interventional procedure for lumbar zygapophysial joint pain, which can be performed more accurately and easily using a guide needle technique. We experienced a case of burn wound formation along the guide needle trajectory, where heat conduction through the guide needle was suggested to have resulted in the burn wound.

Raiofrequency Neurotomy for Lumbar Facet Joint Pain in the Patients with Failed Back Surgery Syndrome / 대한통증학회지

BACKGROUND: A significant number of patients complain of persistent pain or neurologic symptoms after lower back surgery. It is reported that facet joint pain plays a role in failed back surgery syndrome. To the best of our knowledge, there are few studies that have investigated the outcome of radiofrequency neurotomy in the patients with failed back surgery syndrome. METHODS: The study group was composed of thirteen patients who were operated on due to their low back pain, and they displayed no postoperative improvement. All the patients underwent double diagnostic block of the lumbar medial branch of the dorsal rami with using 0.5% bupivacaine. The patients who revealed a positive response to the double diagnostic block were then treated with percutaneous radiofrequency neurotomy. The effect on their pain was evaluated with using a 4 point Likert scale. RESULTS: Eleven patients revealed a positive response to the double diagnostic block. Ten patients were given percutaneous radiofrequency neurotomy. Nine patients showed sustained pain relief for 3 months after the percutaneous radiofrequency neurotomy. CONCLUSIONS: We found lumbar facet joint syndrome in the patients with failed back surgery syndrome by performing double diagnostic block and achieving pain relief during the short term follow-up after percutaneous radiofrequency neurotomy of the lumbar zygapophysial joints. This suggested that facet joint pain should be included in failed back surgery syndrome.

Pharmacodynamic Changes of Atracurium during Induced Liver Cirrhosis Using Carbon Tetrachloride Intoxication in Rabbits / 대한마취과학회지

BACKGROUND: Atracurium appears to be a neuromuscular blocking agent best suited for use in patients with renal failure. The influence on the neuromuscular effect of atracurium has been studied in rabbits with experimental liver cirrhosis induced by subcutaneous injection of carbon tetrachloride (CCl4). METHODS: Cirrhosis was induced in rabbits by CCl4 treatment for 11 weeks. Rabbits were randomly assigned to two groups; control group: corn oil 0.5 ml/kg/2 days sq for 11 weeks; study group: CCl4 0.5 ml/kg/2 days mixed 1 : 1 with corn oil sq for 11 weeks. The dose-response relations of atracurium were studied in sixteen rabbits during thiopental anesthesia. They received atracurium 60, 80 and 100microgram/kg in control group, and 80, 100 and 120microgram/kg in study group, respectively. The time course of atracurium 0.2 mg/kg in sixteen rabbits was evaluated in each groups. Three fragments of each liver lobe at the end of the experimental period were collected and processed for light microscopy, and performed the histological examination. RESULTS: After eleven-week CCl4 treatment, liver histology demonstrated well-defined liver cirrhosis, and increased AST and ALT compared with controls. The calculated ED50 for atracurium were 81.9+/-6.8microgram/kg and 101.1+/-9.4microgram/kg, respectively, in control and study group, and corresponding ED95 was 124.8+/-9.7microgram/kg and 156.1+/-12.1microgram/kg, respectively. There were significant difference between two groups (P < 0.001). The times after atracurium until 95% twitch recovery in control and study group were 31.7+/-6.7 min and 32.8+/-7.4 min, respectively. There were no difference between two groups. CONCLUSIONS: Atracurium in the experimental liver cirrhosis model induced by CCl4 has a decreased potency, but a similar duration of action compared with control. It is suggested that atracurium was also used with monitoring of neuromuscular function in patients with hepatic dysfunction.

Effect of Intraoperative Continuous I.V. Fentanyl on Tourniquet Induced Cardiovascular Changes and Postoperative Preemptive Analgesia in Total Knee Replacements / 대한통증학회지

BACKGROUND: It is difficult to treat tourniquet-induced hypertension despite adequate anesthesia, and the mechanism of that is not known. And it may be possible that intraoperative continuous infusion of opioid induces preemptive analgesia postoperatively. We investigated the effect of intraoperative continuous i.v. fentanyl on tourniquet induced cardiovascular changes and postoperative preemptive analgesia in total knee replacements. METHODS: Sixty patients were randomly assigned to two groups; In study group (1.5microgram/kg loading and 0.5microgram/kg/hr continuous infusion of fentanyl before skin incision and tourniquet inflation) and control group (no treatment). Anesthesia was maintained with enflurane (1-2 MAC) and 50% nitrous oxide in oxygen. Arterial pressure and heart rate were compared between two groups. They received postoperative pain treatment with patient-controlled analgesia (PCA) with fentanyl during the postoperative 48 hours after total knee replacement. Visual analog scale (VAS) scores at either rest or movement were used to assess pain. Total fentanyl dose delivered, number of PCA requests, supplemental analgesics, overall satisfaction score and adverse events were evaluated. RESULTS: There were no significant differences between the two groups on cardiovascular changes by tourniquet induced pain effect. VAS, PCA delivered dose and PCA demands at movement in the 24-48 hour decreased in study group compared with control group (P < 0.05). But there were no significant differences between the two groups on the other time periods except 24-48 hour's patient satisfaction and adverse events. CONCLUSIONS: We suggest that intraoperative continuous i.v. fentanyl infusion dose not affect cardiovascular change by tourniquet induced pain. But it may induce preemptive analgesia postoperatively.

Short Term Follow Up of Whiplash-associated Disorder Patients Treated with Pulsed Radiofrequency Thermocoagulation / 대한마취과학회지

BACKGROUND: Whiplash associated disorder (WAD) is one of the most common causes of neck pain and cervicogenic headache. One proposed method of treating neck pain and cervicogenic headache is the ablation of cervical medial branch with pulsed radiofrequency thermocoagulation (PRFT). This study was a retrospective evaluation of the effect of the PRFT in patients with WAD who did not show any responses to the various conservative treatments. METHODS: Short term outcome was ascertained among 7 patients with the PRFT of cervical medial branches, who had shown positive response to the diagnostic block. During the PRFT under the guidance of C-arm image, impedance and sensory electrical nerve stimulation threshold were assessed. After obtaining appropriate stimulation, PRFT was performed to the cervical medial branches at 42degreesC for 120 seconds. Three out of 7 patients were treated unilaterally. For the assessment of short term outcome, the 4 point Likert scale was adopted. The result was regarded as favorable if pain reduction were more than 50% on the scale. RESULTS: Mean duration of pain was 415.3 +/- 233.4 days. Average follow-up interval was 76.4 +/- 10.1 days. Two patients did not respond favorably to the PRFT. In 5 patients who showed favorable response to the PRFT, the effect lasted on average 76.4 +/- 10.1 days. CONCLUSIONS: The PRFT of cervical medial branches might be an effective treatment modality in patients with WAD and who did not show any responses to the conservative managements.

Reconsideration of Hypoxic Chamber Flight Training through a Pulse Oximetry Monitoring Study in ROKAF

Hypoxia is a serious aviation problem and can always be a source of dangerous aerospace accidents. Hypoxic chamber flight training used to evaluate hypoxia tolerance via TUC (time of useful consciousness) and to become aware of hypoxic symptoms. Because TUC depends on subjective symptoms and lacks strict objectivity, pulse oximetry monitoring has become useful in the aviation environment. In this study, we monitored arterial oxygen saturation (SaO2) by pulse oximetry in the ROKAF subjects (n=33) experiencing hypoxia at the simulated altitude of 25,000 ft. The duration from mask-off to mask-on (TUC), the duration from mask-off to the time of SaO2 of 90% (T90), the duration from 90% to 70% of SaO2(T70), and the SaO2 value at mask-on (bottom SaO2) were examined. The mean bottom SaO2 and TUC were 64.5% and 180 sec, respectively. The subjective hypoxic symptoms were facial flushing, thinking impairment, dyspnea, sweating, anxiety, and so on, in descending order. The majority of the subjects put on their mask before 70% of SaO2 was reached or before they felt any severe symptoms. In comparison with the data of JASDF (Yoneda, 2000), TUC, T90, and T70 were longer in JASDF, but bottom SaO2 and pulse increasing rate during hypoxia (PR/TUC) were higher in ROKAF. Also, TUC in the subjects of this study was much shorter than those of 10 years ago. These may be due to different training protocols, but not enough data exists to explain such difference. The need for the reconsideration of the hypoxic training from the various viewpoints is raised.

A Comparision of Short Term use Effects and Satety of Timoptic(R) with those of Cosopt(R) in Normal Korean

PURPOSE: This study is to compare the clinical effects and safety of 0.5% timolol maleate and 2% dorzolamide hydrochloride combinationis (Cosopt(R)) with those of 0.5% timolol maleate (Timoptic(R)) in normal Korean. METHODS: We instilled Timoptic(R) eye drops two time a day into one eye and Cosopt(R) eyedrops two times a day into the other eye for thirty days and measured the intraocular pressure (IOP) and side effects in normal Korean volunteers. RESULTS: Cosopt(R) was superior to Timoptic(R) in reducing IOP, but had more frequent side effects such as burning, blurred vision, tearing, ocular pain, injection than those of Timoptic(R). However side effects of Cosopt(R) were tolerable enough to refrain from discontinuation. CONCLUSIONS: Due to the greater IOP lowering efficacy of CosoptR compared to that of Timoptic(R), it can be used as an effective substitute in case of uncontrolled IOP with beta blockers alone.