Jong-Yeon Lee

The optimal effect-site concentration of remifentanil to attenuate the pain caused by propofol

Background The injection pain of propofol is a frequent and well-known adverse effect. This study was designed to determine the optimal effect-site concentration of remifentanil for minimizing injection pain during induction with propofol. Methods A total intravenous anesthetic technique was used for patients undergoing general anesthesia and remifentanil was pretreated to reach a certain target concentration before propofol injection. Using Dixons up-and-down method, the degree of pain described by the patient was used to adjust the target concentration of remifentanil for the next patient. Ten success-failure curves (crossovers) were sought to find the effect-site concentration (EC) of remifentanil for minimizing injection pain of propofol. Results The EC of remifentanil in 50% and 95% of adult female population (EC50 and EC95) for minimizing injection pain of propofol were 3.09 ng/ml (95% confidence limits [CI] 2.92-3.30 ng/ml) and 3.78 ng/ml (95% CI 3.45-3.95 ng/ml), respectively. Clinically significant hemodynamic compromise or respiratory complications were not found during remifentanil infusion. Conclusions Maintaining 3.78 ng/ml EC of remifentanil during induction with propofol attenuate propofol injection pain without serious adverse events in female patients undergoing general anesthesia and this method may provide the patients comfort without preparing other drugs for pain relief.

Pulmonary thromboembolism after tourniquet inflation under spinal anesthesia -A case report-

Pulmonary thromboembolism is one of the most important causes of morbidity and mortality in patients undergoing lower extremity orthopedic surgery. Early diagnosis and appropriate management are important clinical challenges. In this case, massive pulmonary embolism causing sudden cardiac arrest was attributed to use of tourniquet inflation during lower extremity orthopedic surgery. Resuscitation procedures were initiated and transesophageal echocardiography revealed pulmonary thromboembolism. Patients with high suspicion for the presence of deep vein thrombus must be monitored thoroughly during limb exsanguinations.

Monitored anesthesia care with remifentanil for femoro-femoral bypass graft patients

The choice of anesthesia in patients with peripheral artery occlusive disease (PAOD) is often challenging for anesthesiologists and surgeons because most of these patients have coronary artery disease and/or other co-morbid diseases. Many such patients also take anticoagulation agents. Van Damme et al. [1] reported that the factors affecting postoperative mortality include chronic renal failure, hypertension, and myocardial infarction. Mangano [2] reported that 5-15% of all patients with PAOD also demonstrate perioperative acute myocardial infarction, with a postoperative mortality rate of 2-15%. In a retrospective study of 14,788 patients who underwent infrainguinal bypass, Singh et al. [3] observed that patients who received general anesthesia showed the highest rates of myocardial infarction, pulmonary complications and re-operation. Unfortunately, many patients with PAOD are prescribed anticoagulants which make it difficult to administer regional anesthesia. Monitored anesthesia care (MAC) with remifentanil through target-controlled infusion and local infiltration is a safe and useful alternative to general anesthesia for infrainguinal vascular surgery. In this report, we describe a patient who was treated by femoro-femoral bypass graft for a left common iliac artery occlusion under MAC. A 70-year-old man 163 cm in height and 63 kg in weight was admitted to our institution due to severe resting pain in both legs. He had severe right coronary artery occlusive disease, which had been treated with the placement of a coronary stent 2 years prior. The patient was on a medication regimen of aspirin and clopidogrel. He exhibited severe stenosis of the left anterior descending and left circumflex coronary arteries on coronary CT, and hypokinesia of the anteroseptum and akinesia of the inferior wall on echocardiography. The patient also had a 3-year history of hypertension and diabetes. A femoral artery angiogram showed right external iliac artery stenosis and complete obstruction of the left common iliac artery (Fig. 1). A stent was inserted into the right iliac artery, but femoral-to-femoral bypass graft surgery was scheduled for revascularization of the left common iliac artery. The placement of a coronary stent was delayed until after the femoral bypass graft due to intractable leg pain. Fig. 1 Lower abdominal aortography shows non-visualization of left common iliac artery to left common femoral artery by complete obstruction (single arrow), stent state of right external iliac artery and non-visualization of right internal iliac artery by obstruction ... The anesthesiologists explained the patients general condition, combined diseases, risks of anesthesia, and MAC method to the patient, his family members and the surgeon. All parties understood the circumstances and agreed to the performance of MAC. Upon arrival at the operating theater, the patients BP was 120/70 mmHg, heart rate was 80 beat/min, and O2 saturation was 99% through a simple facial mask with 4 L/min of oxygen. Oxygen was administered continuously during surgery. We monitored direct arterial pressure, lead II and V5 EKG, bispectral index (BIS, Aspect® Medical Systems, Norwood, MA, USA), pulseoximetry, and end tidal CO2 via nasal cannula to assess the patients respiratory rate. Remifentanil was given at a dose 1.0 ng/ml of effect site concentration (EC) by infusion pump (Orchestra Base Primea®, Fresenius Vial, France) for 5 minutes, and then increased first to 1.5 and then 2.0 ng/ml at 5 minute intervals before local infiltration to minimize patient discomfort and respiratory depression. A 1% lidocaine and 0.25% ropivacaine mixture (1 : 1, 20 ml) was infiltrated at both the inguinal incision site and the subcutaneous tunneling area. We increased the remifentanil EC to 2.5-3.5 ng/ml when painful surgical stimulation occurred, such as femoral artery dissection, subcutaneous tunneling and vascular clamping. When the stimulation ended, the EC was readjusted. We administered isosorbid dinitrate 0.5 µg/kg at the time we started the MAC. We were prepared to decrease the remifentanil EC to 0.3 ng/ml immediately if the patient experienced respiratory depression (less than 7 breaths/min or more than 15 seconds of apnea). Fortunately, no special events such as hypotension, tarchycardia, cardiac events, patient complaints, respiratory depression, or apnea occurred during the procedure. When the remifentanil EC was 3.5 ng/ml, the patients respiratory rate was 10 breaths/min. When necessary, we encouraged the patient to take a deep breath, allowing him to be ventilated sufficiently without requiring assisted ventilation. During the operation, the EC range of remifentanil was 2.0-3.5 ng/ml, the BIS score was greater than 90, and the modified observer assessment of the patient alertness/sedation score was 5 (indicating that the patient was able to promptly open his eyes when an observer whispered his name). The patient stated that he did not feel discomfort or anxiety. He was discharged on postoperative day 4 without any complications, and 1 week after discharge he underwent coronary stent insertion without incident. MAC is usually performed with short acting hypnotics and opioids, which provide excellent anxiolytic and analgesic effects. However, the use of combined hypnotics and opioids may result in respiratory depression, apnea and hypoxia even in healthy volunteers [4]. For this reason, we used only remifentanil in our patient, and increased EC as slowly as possible to prevent hypotension, hypercapnea, or hypoxia from occurring due to respiratory depression. The EC of remifentanil is easily controlled for each level of surgical pain because it has a short context-sensitive half life, does not accumulate and provides rapid, predictable analgesia. Remifentanil is not usually used alone, but when previously used in fiber optic bronchoscopic awake intubation, it yielded excellent patient cooperation and comfort within the 2.4 ± 0.8 ng/ml range [5]. The choice of anesthesia is complex in patients with PAOD, who usually combine coronary artery disease conditions demanding treatment by coronary stent with other complications such as hypertension, diabetes, and antiplatelet medications, like our patient. Surgeons are also often required to provide complex postoperative care for such patients. We decided to use MAC for our patient due to its many advantages over general or regional anesthesia. First, MAC allows clinicians to avoid intubation and hemodynamic instability, and is free from the risks of spinal hematoma and hypotension, urinary retention, and many other complications. Hemodynamic stability is essential to the management of coronary patients, and may also avoid pulmonary complications. In conclusion, surgery was performed successfully under MAC without the occurrence of respiratory depression or cardiac events in our patient, who tolerated the procedure well and was satisfied with the anesthesia.

Fatal pulmonary embolism and coincidental cerebral infarction after spinal anesthesia -A case report-

A pulmonary embolism and cerebral infarction are the second and third most common acute cardiovascular diseases after a myocardial infarction. Early diagnosis and appropriate management are important clinical challenges. In this case, a fatal pulmonary embolism and extensive cerebral infarction caused cardiac arrest during spinal anesthesia for total hip replacement surgery. Transesophageal echocardiography indicated a pulmonary embolism and brain CT showed large area of acute infarction at right middle cerebral artery territory. Pulmonary CT angiogram revealed massive pulmonary embolism findings. This paper reviews this case and suggests other preventive modalities.

Cephalad malposition after central venous catheterization through right internal jugular vein.

Central venous catheterization is performed in the operating room, intensive care unit and emergency room for various reasons. Internal jugular vein is preferred in the operating room due to little chance of pneumothorax and straight route for catheterization to the right atrium. We experienced a case of central venous catheter malposition to cephalad in the right internal jugular vein. A 60-year-old man, 176 cm in height and 82 kg in weight, was presented for Whipples operation due to the bile duct cancer. After completion of anesthesia induction and intubation, patients head was turned left in Trendelenburg position. After skin disinfection, 18 guage, 2 inch thin-walled needle was inserted at the point of sternocleidomastoid (SCM) muscle apex along with medial border of lateral head of SCM muscle about angle of 45 degree to skin without using the finder needle. At the same time, anesthesiologists left 2nd, 3rd, and 4th fingers palpated the patients right carotid artery for avoiding arterial puncture. However, blood was not aspirated, needle was reinserted more medial direction about angle of 70 degree to skin. After aspiration of venous blood from needle, the J shape guide wire was introduced via the guiding needle using Seldinger technique. Introduction of 20 cm of J-shaped wire was done without any problem, except some resistance at 5 cm depth of the internal jugural vein. Seven Fr double lumen catheter (Prime-S®, Sungwon medical, Cheongju, Korea) was advanced to the following J-shaped wire. Blood aspiration was done to remove the air in catheter without any resistance. Catheter was sutured at the proper site and surgery was done as planned. After the operation, the patient was transferred to an intensive care unit. Head and neck antero-posterior view X-ray was checked because the central venous catheter was not seen on chest X-ray. Antero-posterior view of the head and neck showed that central venous catheter was bent sharply to the cephalad in the right internal jugular vein (Fig. 1). We removed malpositioned catheter and reinserted central venous catheter via the same side subclavian vein. The proper position of subcalvian catheter was confirmed by a chest X-ray and the patient discharged at postoperative day 13. Fig. 1 Neck anteroposterior view shows that central venous catheter is bent sharply to the cephalad in right internal jugular vein. As one of the various complications, catheter malposition via Internal jugular vein (IJV) can be associated with central venous catheterization via IJV (5.3%) [1]. There are many case reports of malpositioning central venous catheter that were positioned in the jugular venous arch via the right subclavian vein [2], in the internal thoracic vein via the internal jugular vein [3] etc. However, this is the first case of malposition of the catheter, which was bent upward. Bending the catheter is very rare because the right internal jugular vein is the straight route for catheterization to the right atrium. Although there was some resistance during introduction of the J-shaped wire, blood aspiration via catheter was normal, dripping of the fluid seemed normal and central venous pressure curve showed no other abnormal findings. We postulate that the J-shaped wire was bent in the cephalad direction at the moment of resistance. The other postulated cause is an acute angle of the introducing needle when it punctured the internal jugular vein. We cannot rule out the anatomical variation of the external jugular vein and internal jugular vein. Deslaugiers et al. [4] reported that 60% of the external jugular vein is drained to junction of the internal jugular vein and subclavian vein, drained to the subclavian vein in 36%, and drained to the internal jugular vein in 4%. However, we did not confirm the anatomical variation with venous angiogram. It seems that we should be careful when we introduce the wire with some resistance. Malpositioning of the catheter results in monitoring inaccurate central venous pressure, damage to vascular wall, and forming the thrombus. However, the chance of thrombus formation is very low since the blood flow velocity is very fast in the internal jugular vein. In addition, it is impossible that the infused drug inflows to the brain. Although, the most precise method to confirm the complications is examination of the X-ray after the catheterization, ultrasono-guided central venous catheter placement is increasing the success rate, shortening the procedure time, decreasing the complication and the easiest method for acknowledging the direction of catheter, needle and guide wire during the entire catheterization process [5]. In summary, if there is any problem during the central venous catheterization, ultrasonography can be used for optimal catheter placement, and prevention of complications. Additionally, X-ray must be examined to confirm the position of the catheter and incidental complication.

Unexpected difficulty in ventilating the lungs after tracheal intubation -A case report-

We experienced difficulty in ventilating the lungs of a patient after tracheal intubation. After intubation, an insufficient amount of tidal volume (VT) was delivered to the patient and the fiberoptic bronchoscopic examination identified partial abutment of the endotracheal tube (ETT) orifice against the tracheal wall. After various attempts to correctly place the ETT, a double-lumen endotracheal tube was placed to achieve a sufficient VT. It is important to notice that even an appropriately placed ETT may get obstructed due to the left sided bevel at its tip.

Anesthetic management for cesarean section in a patient with Budd-Chiari syndrome - A case report -

Budd-Chiari syndrome (BCS) represents a spectrum of disease states resulting in hepatic venous outflow occlusion. Prothrombotic disorders, such as protein S deficiency may cause thrombosis of the portal and hepatic veins. We report the management of a 30-year-old BCS primigravida with protein S deficiency and destroyed lung by the pulmonary tuberculosis scheduled for Cesarean section. Moreover, patients lungs were destroyed by the pulmonary tuberculosis. Spinal anesthesia was selected for the anesthetic management. The patient recovered without any complication and discharged from hospital on the fifth postoperative day.