Radiation safety: a focus on lead aprons and thyroid shields in interventional pain management.

C-arm fluoroscopy is useful equipment in interventional pain management because it helps to guide correct needle targeting for the accurate injection and drug delivery. However, due to increased use of C-arm fluoroscopy in various pain procedures, the risk of radiation exposure is a significant concern for pain physicians. The harmful biological effects of ionizing radiation on the human body are well known. It is therefore necessary to strive to reduce radiation exposure. Lead aprons with thyroid shields are the most fundamental radiation protective devices for interventional procedures, and are very effective. However, the operator's radiation safety cannot be guaranteed because pain physicians seem to lack sufficient interest, knowledge, and awareness about radiation safety. Also, inappropriate care and use of radiation protective devices may result in a higher risk of radiation exposure. The purpose of this article was to review the literature on radiation safety with a focus on lead aprons and thyroid shields and present recommendations related to those devices during C-arm fluoroscopic-guided interventions by pain physicians.

Comparison of the expression of cluster of differentiation (CD)39 and CD73 between propofol- and sevoflurane-based anaesthesia during open heart surgery.

High expression of cluster of differentiation (CD)39 and CD73 has cardio-protective effects. We hypothesised that the expression of CD39 and CD73 would differ between propofol- and volatile anaesthetic-based anaesthesia in patients undergoing open heart surgery (OHS). The objective of this prospective randomized trial was to compare the changes in CD39 and CD73 levels in CD4+ T cells between propofol- and sevoflurane-based anaesthesia during OHS. The study randomly allocated 156 patients undergoing OHS to a propofol or sevoflurane group. Blood was obtained preoperatively and up to 48 hours after weaning from cardiopulmonary bypass (CPB). The expression levels of CD39 and CD73 in circulating CD4+ T cells, serum cytokines and other laboratory parameters were analysed. The primary outcome was the expression of CD39 and CD73 on CD4+ T cells. Demographic data and perioperative haemodynamic changes did not show significant differences between the two groups. The expression of CD39 and CD73 in the sevoflurane group was significantly lower than in the propofol group (P < 0.001). Other laboratory findings including cardiac enzymes and cytokine levels, did not show significant intergroup differences. Propofol attenuated the decrease in CD39 and CD73 in circulating CD4+ T cells compared to sevoflurane-based anaesthesia during OHS.

Enhancement of 5-HT2A receptor function and blockade of Kv1.5 by MK801 and ketamine: implications for PCP derivative-induced disease models.

MK801 and ketamine, which are phencyclidine (PCP) derivative N-methyl-d-aspartate receptor (NMDAr) blockers, reportedly enhance the function of 5-hydroxytryptamine (HT)-2A receptors (5-HT2ARs). Both are believed to directly affect the pathogenesis of schizophrenia, as well as hypertension. 5-HT2AR signaling involves the inhibition of Kv conductance. This study investigated the interaction of these drugs with Kv1.5, which plays important roles in 5-HT2AR signaling and in regulating the excitability of the cardiovascular and nervous system, and the potential role of this interaction in the enhancement of the 5-HT2AR-mediated response. Using isometric organ bath experiments with arterial rings and conventional whole-cell patch-clamp recording of Chinese hamster ovary (CHO) cells ectopically overexpressing Kv1.5, we examined the effect of ketamine and MK801 on 5-HT2AR-mediated vasocontraction and Kv1.5 channels. Both ketamine and MK801 potentiated 5-HT2AR-mediated vasocontraction. This potentiation of 5-HT2AR function occurred in a membrane potential-dependent manner, indicating the involvement of ion channel(s). Both ketamine and MK801 rapidly and directly inhibited Kv1.5 channels from the extracellular side independently of NMDArs. The potencies of MK801 in facilitating the 5-HT2AR-mediated response and blocking Kv1.5 were higher than those of ketamine. Our data demonstrated the direct inhibition of Kv1.5 channels by MK801/ketamine and indicated that this inhibition may potentiate the functions of 5-HT2ARs. We suggest that 5-HT2AR-Kv1.5 may serve as a receptor-effector module in response to 5-HT and is a promising target in the pathogenesis of MK801-/ketamine-induced disease states such as hypertension and schizophrenia.

The radiation safety education and the pain physicians' efforts to reduce radiation exposure.

BACKGROUND: C-arm fluoroscopy equipment is important for interventional pain management and can cause radiation injury to physicians and patients. We compared radiation safety education and efforts to reduce the radiation exposure of pain specialists. METHODS: A survey of 49 pain specialists was conducted anonymously in 2016. The questionnaire had 16 questions. That questionnaire was about radiation safety knowledge and efforts to reduce exposure. We investigated the correlation between radiation safety education and efforts of radiation protection. We compared the results from 2016 and a published survey from 2011. RESULTS: According to the 2016 survey, all respondents used C-arm fluoroscopy in pain interventions. Nineteen respondents (39%) had received radiation safety education. Physicians had insufficient knowledge about radiation safety. When the radiation safety education group and the non-education group are compared, there was no significant difference in efforts to reduce radiation exposure and radiation safety knowledge. When the 2011 and 2016 surveys were compared, the use of low dose mode (P = 0.000) and pulsed mode had increased significantly (P = 0.001). The number checking for damage to radiation protective garments (P = 0.000) and use of the dosimeter had also increased significantly (P = 0.009). But there was no significant difference in other efforts to reduce radiation exposure. CONCLUSIONS: Pain physicians seem to lack knowledge of radiation safety and the number of physicians receiving radiation safety education is low. According to this study, education does not lead to practice. Therefore, pain physicians should receive regular radiation safety education and the education should be mandatory.

Facilitation of serotonin-induced contraction of rat mesenteric artery by ketamine.

Ketamine is an anesthetic with hypertensive effects, which make it useful for patients at risk of shock. However, previous ex vivo studies reported vasodilatory actions of ketamine in isolated arteries. In this study, we reexamined the effects of ketamine on arterial tones in the presence and absence of physiological concentrations of 5-hydroxytryptamine (5-HT) and norepinephrine (NE) by measuring the isometric tension of endothelium-denuded rat mesenteric arterial rings. Ketamine little affected the resting tone of control mesenteric arterial rings, but, in the presence of 5-HT (100~200 nM), ketamine (10~100 µM) markedly contracted the arterial rings. Ketamine did not contract arterial rings in the presence of NE (10 nM), indicating that the vasoconstrictive action of ketamine is 5-HT-dependent. The concentration-response curves (CRCs) of 5-HT were clearly shifted to the left in the presence of ketamine (30 µM), whereas the CRCs of NE were little affected by ketamine. The left shift of the 5-HT CRCs caused by ketamine was reversed with ketanserin, a competitive 5-HT2A receptor inhibitor, indicating that ketamine facilitated the activation of 5-HT2A receptors. Anpirtoline and BW723C86, selective agonists of 5-HT1B and 5-HT2B receptors, respectively, did not contract arterial rings in the absence or presence of ketamine. These results indicate that ketamine specifically enhances 5-HT2A receptor-mediated vasoconstriction and that it is vasoconstrictive in a clinical setting. The facilitative action of ketamine on 5-HT2A receptors should be considered in ketamine-induced hypertension as well as in the pathogenesis of diseases such as schizophrenia, wherein experimental animal models are frequently generated using ketamine.

Diagnosis Accuracy of Mean Arterial Pressure Variation during a Lung Recruitment Maneuver to Predict Fluid Responsiveness in Thoracic Surgery with One-Lung Ventilation.

Background. Lung recruitment maneuver (LRM) during thoracic surgery can reduce systemic venous return and resulting drop in systemic blood pressure depends on the patient's fluid status. We hypothesized that changes in systemic blood pressure during the transition in LRM from one-lung ventilation (OLV) to two-lung ventilation (TLV) may provide an index to predict fluid responsiveness. Methods. Hemodynamic parameters were measured before LRM (T0); after LRM at the time of the lowest mean arterial blood pressure (MAP) (T1) and at 3 minutes (T2); before fluid administration (T3); and 5 minutes after ending it (T4). If the stroke volume index increased by >25% following 10 mL/kg colloid administration for 30 minutes, then the patients were assigned to responder group. Results. Changes in MAP, central venous pressure (CVP), and stroke volume variation (SVV) between T0 and T1 were significantly larger in responders. Areas under the curve for change in MAP, CVP, and SVV were 0.852, 0.759, and 0.820, respectively; the optimal threshold values for distinguishment of responders were 9.5 mmHg, 0.5 mmHg, and 3.5%, respectively. Conclusions. The change in the MAP associated with LRM at the OLV to TLV conversion appears to be a useful indicator of fluid responsiveness after thoracic surgery. TRIAL REGISTRATION: This trial is registered at Clinical Research Information Service with KCT0000774.

Postoperative Delirium in Elderly Patients Undergoing Hip Fracture Surgery in the Sugammadex Era: A Retrospective Study.

BACKGROUND: Residual neuromuscular block (NMB) after general anesthesia has been associated with pulmonary dysfunction and hypoxia, which are both associated with postoperative delirium (POD). We evaluated the effects of sugammadex on POD in elderly patients who underwent hip fracture surgery. METHODS: Medical records of 174 consecutive patients who underwent hip fracture surgery with general anesthesia were reviewed retrospectively to compare the perioperative incidence of POD, pulmonary complications, time to extubation, incidence of hypoxia, and laboratory findings between patients treated with sugammadex and those treated with a conventional cholinesterase inhibitor. RESULTS: The incidence of POD was not significantly different between the two groups (33.3% versus 36.5%, resp.; P = 0.750). Postoperative pulmonary complications and laboratory findings did not showed significant intergroup difference. However, time to extubation (6 ± 3 versus 8 ± 3 min; P < 0.001) and the frequency of postoperative hypoxia were significantly lower (23% versus 43%; P = 0.010) in the sugammadex group than in the conventional cholinesterase inhibitor group. CONCLUSION: Sugammadex did not reduce POD or pulmonary complications compared to conventional cholinesterase inhibitors, despite reducing time to extubation and postoperative hypoxia in elderly patients who underwent hip fracture surgery under general anesthesia.

The influence of different mechanical ventilator settings of peak inspiratory pressure on stroke volume variation in pediatric cardiac surgery patients.

BACKGROUND: The usefulness of dynamic parameters derived by heart-lung interaction for fluid responsiveness in pediatric patients has been revealed. However, the effects of peak inspiratory pressure (PIP) that could affect the absolute values and the accuracy in pediatric patients have not been well established. METHODS: Participants were 30 pediatric patients who underwent ventricular septal defect repair. After completion of surgical procedure and sternum closure, mean arterial blood pressure, heart rate, central venous pressure, cardiac output, cardiac index and stroke volume variation (SVV) were measured at PIP 10 cmH2O (PIP10), at PIP 15 cmH2O (PIP15), at PIP 20 cmH2O (PIP20) and at PIP 25 cmH2O (PIP25). RESULTS: SVV at PIP15 was larger than that at PIP10 (13.7 ± 2.9% at PIP10 vs 14.7 ± 2.5% at PIP15, P < 0.001) and SVV at PIP20 was larger than that at PIP10 and PIP15 (13.7 ± 2.9% at PIP10 vs 15.4 ± 2.5% at PIP20, P < 0.001; 14.7 ± 2.5% at PIP15 vs 15.4 ± 2.5% at PIP20, P < 0.001) and SVV at PIP25 was larger than that at PIP10 and PIP15 and PIP20 (13.7 ± 2.9% at PIP10 vs 17.4 ± 2.4% at PIP25, P < 0.001; 14.7 ± 2.5% at PIP15 vs 17.4 ± 2.4% at PIP25, P < 0.001; 15.4 ± 2.5% at PIP20 vs 17.4 ± 2.4% at PIP25, P < 0.001). CONCLUSIONS: SVV is affected by different levels of PIP in same patient and under same volume status. This finding must be taken into consideration when SVV is used to predict fluid responsiveness in mechanically ventilated pediatric patients.

The Radiation Exposure of Radiographer Related to the Location in C-arm Fluoroscopy-guided Pain Interventions.

BACKGROUND: Although a physician may be the nearest to the radiation source during C-arm fluoroscope-guided interventions, the radiographer is also near the fluoroscope. We prospectively investigated the radiation exposure of radiographers relative to their location. METHODS: The effective dose (ED) was measured with a digital dosimeter on the radiographers' left chest and the side of the table. We observed the location of the radiographers in each procedure related to the mobile support structure of the fluoroscope (Groups A, M and P). Data about age, height, weight, sex, exposure time, radiation absorbed dose (RAD), and the ED at the radiographer's chest and the side of the table was collected. RESULTS: There were 51 cases for Group A, 116 cases for Group M and 144 cases for Group P. No significant differences were noted in the demographic data such as age, height, weight, and male to female ratio, and exposure time, RAD and ED at the side of the table. Group P had the lowest ED (0.5 ± 0.8 µSv) of all the groups (Group A, 1.6 ± 2.3 µSv; Group M, 1.3 ± 1.9 µSv; P < 0.001). The ED ratio (ED on the radiographer's chest/ED at the side of the table) of Group A was the highest, and the ED radio of Group P was the lowest of all the groups (Group A, 12.2 ± 21.5%; Group M, 5.7 ± 6.5%; Group P, 2.5 ± 6.7%; P < 0.001). CONCLUSIONS: Radiographers can easily reduce their radiation exposure by changing their position. Two steps behind the mobile support structure can effectively decrease the exposure of radiographers by about 80%.

Clinical effects of intrathecal fentanyl on shoulder tip pain in laparoscopic total extraperitoneal inguinal hernia repair under spinal anaesthesia: a double-blind, prospective, randomized controlled trial.

OBJECTIVE: The study evaluated the clinical intraoperative effects of intrathecal administration of fentanyl on shoulder tip pain in patients undergoing laparoscopic total extraperitoneal inguinal hernia repair (TEP) under spinal anaesthesia. METHODS: Patients undergoing TEP were allocated in a double-blinded, prospective, randomized manner to two groups. Spinal anaesthesia was induced by intrathecal administration of 2.8 ml of 0.5% hyperbaric bupivacaine (14 mg) in the control group and with 2.6 ml of 0.5% hyperbaric bupivacaine (13 mg) and 10 µg fentanyl (0.2 ml) in the experimental group. RESULTS: The quality of muscle relaxation, adequacy of operative space and incidence of pneumoperitoneum were similar in the two groups (n = 36 per group). Compared with the control group, the experimental group had significantly fewer cases of hypotension (12 [33.3%]) versus 23 [63.9%]) and shoulder tip pain (nine [25%] versus 18 [50%]). Intraoperative shoulder tip pain was more severe in the control group than in the experimental group. CONCLUSIONS: Addition of intrathecal fentanyl to local anaesthetic can relieve shoulder tip pain with no change in complications, especially hypotension, during TEP under spinal anaesthesia.

Pneumomediastinum after arthroscopic shoulder surgery -A case report-.

An 86-year-old female with a history of right rotator cuff injury was admitted for arthroscopic shoulder surgery under general anesthesia. There were no remarkable immediate postoperative complications. However, while recovering in the general ward, she developed dyspnea with hypoxia. She was immediately treated with oxygen, and antibiotics after pneumomediastinum was confirmed on both chest x-ray and chest computed tomography. Subcutaneous emphysema on either face or neck followed by arthroscopic shoulder surgery was common, but pneumomediastinum with hypoxia is a rare but extremely dangerous complication. Thus we would like to report our case and its pathology, the diagnosis, the treatment and prevention, with literature review.

A Randomized Controlled Trial about the Levels of Radiation Exposure Depends on the Use of Collimation C-arm Fluoroscopic-guided Medial Branch Block.

BACKGROUND: C-arm fluoroscope has been widely used to promote more effective pain management; however, unwanted radiation exposure for operators is inevitable. We prospectively investigated the differences in radiation exposure related to collimation in Medial Branch Block (MBB). METHODS: This study was a randomized controlled trial of 62 MBBs at L3, 4 and 5. After the patient was laid in the prone position on the operating table, MBB was conducted and only AP projections of the fluoroscope were used. Based on a concealed random number table, MBB was performed with (collimation group) and without (control group) collimation. The data on the patient's age, height, gender, laterality (right/left), radiation absorbed dose (RAD), exposure time, distance from the center of the field to the operator, and effective dose (ED) at the side of the table and at the operator's chest were collected. The brightness of the fluoroscopic image was evaluated with histogram in Photoshop. RESULTS: There were no significant differences in age, height, weight, male to female ratio, laterality, time, distance and brightness of fluoroscopic image. The area of the fluoroscopic image with collimation was 67% of the conventional image. The RAD (29.9 ± 13.0, P = 0.001) and the ED at the left chest of the operators (0.53 ± 0.71, P = 0.042) and beside the table (5.69 ± 4.6, P = 0.025) in collimation group were lower than that of the control group (44.6 ± 19.0, 0.97 ± 0.92, and 9.53 ± 8.16), resepectively. CONCLUSIONS: Collimation reduced radiation exposure and maintained the image quality. Therefore, the proper use of collimation will be beneficial to both patients and operators.

Radiation Exposure of the Hand and Chest during C-arm Fluoroscopy-Guided Procedures.

BACKGROUND: The C-arm fluoroscope is an essential tool for the intervention of pain. The aim of this study was to investigate the radiation exposure experienced by the hand and chest of pain physicians during C-arm fluoroscopy-guided procedures. METHODS: This is a prospective study about radiation exposure to physicians during transforaminal epidural steroid injection (TFESI) and medial branch block (MBB). Four pain physicians were involved in this study. Data about effective dose (ED) at each physician's right hand and left side of the chest, exposure time, radiation absorbed dose (RAD), and the distance from the center of the X-ray field to the physician during X-ray scanning were collected. RESULTS: Three hundred and fifteen cases were included for this study. Demographic data showed no significant differences among the physicians in the TFESIs and MBBs. In the TFESI group, there was a significant difference between the ED at the hand and chest in all the physicians. In physician A, B and C, the ED at the chest was more than the ED at the hand. The distance from the center of the X-ray field to physician A was more than that of the other physicians, and for the exposure time, the ED and RAD in physician A was less than that of the other physicians. In the MBB group, there was no difference in the ED at the hand and chest, except for physician D. The distance from the center of the X-ray field to physician A was more than that of the other physicians and the exposure time in physician A was less than that of the other physicians. CONCLUSIONS: In conclusion, the distance from the radiation source, position of the hand, experience and technique can correlate with the radiation dose.

Assessment of coagulation with 6% hydroxyethyl starch 130/0.4 in cesarean section.

BACKGROUND: Third-generation hydroxyethyl starch (HES) solutions have been developed to minimize negative effects on hemostasis. In normal pregnancy, the coagulation activity increases, reaching a maximum around term. This study examined the effects of hemodilution with HES 130/0.4 (6%) on blood coagulation in parturients in vivo and in vitro. METHODS: Forty parturients scheduled for cesarean sections were assigned randomly to receive either 500 or 1,000 ml of HES 130/0.4 (6%). Rotation thromboelastometry (ROTEM®) measurements were performed before and after administering HES 130/0.4 (6%). In addition, blood samples obtained from 20 randomly selected parturients were diluted 10% to 40% using HES 130/0.4 (6%), and ROTEM® measurements were performed before and after dilution. The changes from baseline and the effects of dilution were analyzed by ROTEM® parameters. RESULTS: Infusions of 500 or 1,000 ml of HES 130/0.4 (6%) in the parturients altered the clot formation time, α angle, and maximal clot firmness, although all remained within normal ranges. HES 130/0.4 (6%) affected in vitro blood coagulation in parturients' blood containing 10, 20, 30, and 40% HES. The clotting time was prolonged at each dilution percentage, but remained within the normal range. Other parameters showed an impairment of the coagulation system. CONCLUSIONS: Blood coagulation in parturients may be compromised at high dilution ratios of HES 130/0.4 (6%) to blood. Nevertheless, the infusion of 1,000 ml of HES 130/0.4 (6%) in normal parturients did not significantly affect blood coagulation.

Spectral entropy for assessing the depth of propofol sedation.

BACKGROUND: For patients in the intensive care unit (ICU) or under monitored anesthetic care (MAC), the precise monitoring of sedation depth facilitates the optimization of dosage and prevents adverse complications from underor over-sedation. For this purpose, conventional subjective sedation scales, such as the Observer's Assessment of Alertness/Sedation (OAA/S) or the Ramsay scale, have been widely utilized. Current procedures frequently disturb the patient's comfort and compromise the already well-established sedation. Therefore, reliable objective sedation scales that do not cause disturbances would be beneficial. We aimed to determine whether spectral entropy can be used as a sedation monitor as well as determine its ability to discriminate all levels of propofol-induced sedation during gradual increments of propofol dosage. METHODS: In 25 healthy volunteers undergoing general anesthesia, the values of response entropy (RE) and state entropy (SE) corresponding to each OAA/S (5 to 1) were determined. The scores were then analyzed during each 0.5 mcg/ml- incremental increase of a propofol dose. RESULTS: We observed a reduction of both RE and SE values that correlated with the OAA/S (correlation coefficient of 0.819 in RE-OAA/S and 0.753 in SE-OAA/S). The RE and SE values corresponding to awake (OAA/S score 5), light sedation (OAA/S 3-4) and deep sedation (OAA/S 1-2) displayed differences (P < 0.05). CONCLUSIONS: The results indicate that spectral entropy can be utilized as a reliable objective monitor to determine the depth of propofol-induced sedation.

The effects of magnesium on the course of atrial fibrillation and coagulation in patients with atrial fibrillation undergoing mitral valve annuloplasty.

BACKGROUND: Atrial fibrillation (AF) is the most common cardiac arrhythmia. Magnesium has been reported to be effective in reducing the incidence or prophylaxis of AF. Magnesium is also an essential constituent of many enzyme systems and plays a physiological role in coagulation regulation. The aim of the present study was to examine the effects of magnesium, whether magnesium infusion might decrease the incidence of AF and induce hypocoagulable state in patients with AF, who were undergoing mitral valve annuloplasty. METHODS: This prospective laboratory study was performed using blood from patients with AF undergoing mitral valve annuloplasty. The radial artery was punctured with a 20 gauge catheter and used for monitoring continuous arterial pressure and blood sampling. After anesthesia induction, 4 g of magnesium was mixed with 100 ml normal saline and infused for 5 minutes. Magnesium, calcium, activated clotting time (ACT) and thromboelastographic parameters were checked before and 60 minutes after the magnesium infusion. The electrocardiography changes after magnesium infusion were also checked before commencing cardiopulmonary bypass. RESULTS: After magnesium infusion, the serum level of magnesium increased significantly but serum calcium did not change significantly. ACT did not change significantly before or after magnesium infusion. The thromboelastographic parameters showed no significant changes before or after magnesium infusion. None of the patients converted to sinus rhythm from AF after the magnesium infusion. CONCLUSIONS: A magnesium infusion did not influence the course of AF and coagulation in patients during prebypass period with AF undergoing mitral valve annuloplasty.

A Study to Compare the Radiation Absorbed Dose of the C-arm Fluoroscopic Modes.

BACKGROUND: Although many clinicians know about the reducing effects of the pulsed and low-dose modes for fluoroscopic radiation when performing interventional procedures, few studies have quantified the reduction of radiation-absorbed doses (RADs). The aim of this study is to compare how much the RADs from a fluoroscopy are reduced according to the C-arm fluoroscopic modes used. METHODS: We measured the RADs in the C-arm fluoroscopic modes including 'conventional mode', 'pulsed mode', 'low-dose mode', and 'pulsed + low-dose mode'. Clinical imaging conditions were simulated using a lead apron instead of a patient. According to each mode, one experimenter radiographed the lead apron, which was on the table, consecutively 5 times on the AP views. We regarded this as one set and a total of 10 sets were done according to each mode. Cumulative exposure time, RADs, peak X-ray energy, and current, which were viewed on the monitor, were recorded. RESULTS: Pulsed, low-dose, and pulsed + low-dose modes showed significantly decreased RADs by 32%, 57%, and 83% compared to the conventional mode. The mean cumulative exposure time was significantly lower in the pulsed and pulsed + low-dose modes than in the conventional mode. All modes had pretty much the same peak X-ray energy. The mean current was significantly lower in the low-dose and pulsed + low-dose modes than in the conventional mode. CONCLUSIONS: The use of the pulsed and low-dose modes together significantly reduced the RADs compared to the conventional mode. Therefore, the proper use of the fluoroscopy and its C-arm modes will reduce the radiation exposure of patients and clinicians.

Abrupt formation and spontaneous resolution of a right atrial thrombus detected by intraoperative transesophageal echocardiography during replacement of an abdominal aortic aneurysm.

Intraoperative formation of a thrombus in the right atrium and its management has occasionally been reported. However, spontaneous resolution of right atrial thrombi, without any event, is rare. We report a case of abrupt right atrial thrombus formation and spontaneous resolution, with no events, detected by transesophageal echocardiography during the replacement of an abdominal aortic aneurysm.

Haemodynamic effects during endoscopic vein harvest of the saphenous vein for off-pump coronary artery bypass grafting surgery.

OBJECTIVE: Endoscopic vein harvest (EVH) for coronary artery bypass grafting surgery is performed with carbon dioxide (CO2) insufflation for visualization and dissection. The insufflated CO2 is rapidly absorbed into the body and may influence haemodynamics. However, the haemodynamic changes during EVH have not been clearly defined. This study evaluated the haemodynamic effects during EVH of the saphenous vein for off-pump coronary artery bypass grafting surgery (OPCAB). METHODS: After fixing the position for harvesting of the left internal mammary artery, EVH of the saphenous vein was performed at a maximum CO2 pressure of 12 mmHg and a flow of 3 l/min. The haemodynamic parameters were measured before and just after the end of endoscopic vein harvest. RESULTS: One hundred patients were studied. The end-tidal CO2 pressure (P(ET)CO2, 35.0 +/- 2.7 vs. 52.0 +/- 6.2 mmHg), partial pressure of arterial CO2 (PaCO2, 35.1 +/- 3.1 vs. 52.5 +/- 4.3 mmHg), mixed venous oxygen saturation (SvO2, 75.6 +/- 4.1 vs. 82.0 +/- 1.6%), cardiac index (2.7 +/- 0.6 vs. 3.3 +/- 0.6 l/min/m2), and cerebral oxygen saturation (ScO2, left: 63.5 +/- 7.9 vs. 73.3 +/- 8.4; right: 62.2 +/- 8.0 vs. 72.3 +/- 6.3%) differed significantly between before and after CO2 insufflation, whereas mean systemic blood pressure, mean pulmonary artery blood pressure, central venous pressure, heart rate, partial pressure of arterial oxygen, and peak inspiratory pressure did not differ significantly between before and after CO2 insufflation. CONCLUSIONS: EVH, at a maximum CO2 pressure of 12 mmHg and a flow of 3 l/min, of the saphenous vein for OPCAB was associated with hypercarbia and a tolerable range of hypercarbia (PaCO2 < 60 mmHg) increased the cardiac index and ScO2 without any complications.

Salbutamol to facilitate management of acute hyperkalemia in liver transplantation: a case report.

PURPOSE: Acute hyperkalemia is a frequent, potentially life-threatening complication in orthotopic liver transplantation (OLT). We describe a case of acute hyperkalemia during the pre-anhepatic stage that remained persistent despite conventional treatment, including calcium salts, insulin and glucose, sodium bicarbonate, and furosemide. CLINICAL FEATURES: A 50-yr-old man with end-stage hepatitis B liver cirrhosis underwent living donor liver transplantation, receiving a right lobe graft donated by his son. The initial serum potassium concentration was 4.6 mEq l(-1). Despite conventional management, the serum potassium concentration increased to 6.6 mEq l(-1), intraoperatively. Since about 90 min elapsed from the division of the hepatic artery and the portal vein to the clamping of the suprahepatic inferior vena cava, the persistent hyperkalemia may have resulted from loss of potassium from ischemic liver cells into the systemic circulation. After incorporating nebulized salbutamol, a selective beta(2)-agonist, into the combined therapeutic regimen (sodium bicarbonate and insulin with glucose), the serum potassium concentrations rapidly normalized. CONCLUSIONS: This case suggests that acute and relatively refractory hyperkalemia can develop when surgical interruption of hepatic inflow is prolonged during hepatectomy in patients undergoing OLT using the piggyback technique. In such situations, incorporating nebulized salbutamol with a conventional anti-hyperkalemia strategy can provide an effective therapeutic option to treat hyperkalemia, even during the anhepatic stage.