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Renal dysfunction after coronary artery bypass grafting is common and is associated with increased morbidity and mortality. A number of strategies with potential renoprotective effects have been investigated, but no single one has been found to warrant routine use in CABG except fenoldopam in which the data to date appear promising. Other measures such as avoidance of nephrotoxic agents, including recent radiocontrast for coronary angiography, may reduce the incidence of renal dysfunction after cardiac surgery and should be implemented in routine care, whenever possible. The best renal protection strategy remains the same as for other organ protection and consists of optimizing haemodynamics, oxygenation, metabolic states and hydration.

Observational studies on transfusion in trauma comparing high versus low plasma:erythrocyte ratio were prone to survivor bias because plasma administration typically started later than erythrocytes. Therefore, early deaths were categorized in the low plasma:erythrocyte group, whereas early survivors had a higher chance of receiving a higher ratio. When early deaths were excluded, however, a bias against higher ratio can be created. Survivor bias could be reduced by performing before-and-after studies or treating the plasma:erythrocyte ratio as a time-dependent covariate.We reviewed 26 studies on blood ratios in trauma. Fifteen of the studies were survivor bias-unlikely or biased against higher ratio; among them, 10 showed an association between higher ratio and improved survival, and five did not. Eleven studies that were judged survivor bias-prone favoring higher ratio suggested that a higher ratio was superior.Without randomized controlled trials controlling for survivor bias, the current available evidence supporting higher plasma:erythrocyte resuscitation is inconclusive.

Background Cannulation of the internal jugular vein (IJV) is traditionally performed using the central-longitudinal approach. Pneumothorax, carotid artery puncture, and failure to cannulate are uncommon, but by no means rare, complications. Ultrasound (US) guidance for IJV cannulation has reduced but not eliminated such complications. Technique We herein introduce a new approach, coined the “medial-transverse approach” due to the perpendicular angle at which the introducer needle is advanced toward the IJV from the median to lateral direction. Discussion The direction of the introducer needle is not toward the lung, thus virtually eliminating the possibility of pneumothorax. The image of the entire needle is seen when the US probe is typically orientated for a short-axis view of the IJV and carotid artery, thus improving the chance of uncomplicated IJV puncture. We have used this technique with apparent success in thousands of cases over the past 20 years in two different institutions. Conclusion A modified IJV cannulation technique that seems to have unique advantages over traditional approaches has been described. This technique is compatible with the blind and US-guided approaches.

KEY POINTS On Dec. 14, 2016, the US Food and Drug Administration warned that anesthetics and sedatives used in children younger than three years of age, or in pregnant women in their third trimester, who were undergoing general anesthesia for more than three hours or used anesthetics repeatedly may

Thoracic trauma leading to multiple fractured ribs (MFR) remains very common. Good analgesia may help to improve a patient's respiratory mechanics and to avoid intubation of the trachea for ventilatory support and therefore may dramatically alter the course of recovery. We herein review the analgesia options for patients with MFR.For healthy patients with one to two fractured ribs, systemic analgesics may suffice. For more than three to four fractured ribs, studies and experience have reaffirmed the superior analgesia made possible with thoracic epidural, thoracic paravertebral, and intercostal blocks. From experience, interpleural block has significant drawbacks. Catheterization allows the continuation of analgesia for 2 or more days with just one block. Use of the landmark technique is usually satisfactory for accurate block placement but ultrasound and nerve stimulation are showing promise in further improving needle and catheter placement accuracy, especially in the presence of difficult anatomy.Thoracic epidural, thoracic paravertebral, and intercostal blocks are the top choices for patients with MFR and they are of equivalent efficacy. Each has unique advantages and disadvantages. Our preference tends to be the thoracic paravertebral approach.

Subglottic stenosis (SGS) can be congenital (rare) or acquired. The most common cause of acquired SGS is prolonged intubation. The narrowest and most susceptible area of the subglottic trachea is the portion circumscribed by the cricoid cartilage (as opposed to other portions where the cartilage rings are incomplete and the dimensions are wider). Granulation after extubation begins early although many children are diagnosed weeks/months later. Clinical presentation is characterised by the onset of varying degrees of dyspnoea and stridor postextubation. Other causes of stridor (eg, transient postintubation oedema—characterised by onset shortly after extubation and good response to nebulised epinephrine and systemic steroids; viral croup—low-grade fever, inspiratory stridor and …

When a professional soccer player required ankle surgery, his electrocardiogram showed several abnormalities.

If tracheal intubation is not possible using direct laryngoscopy, one option is to use a laryngeal mask airway (LMA) through which an endotracheal tube (ETT) can be passed. In children, however, the size of an uncuffed ETT that can pass through the lumen of an LMA is sometimes too small for the trachea, resulting in gas leakage around the ETT. Using a cuffed ETT may reduce the gas leak but withdrawal of the LMA is then prevented by the pilot balloon. In this study, the largest sizes of cuffed and uncuffed Mallinckrodt™ ETTs that could pass with ease through various sizes of paediatric Classic™ and ProSeal™ LMAs were documented. For cuffed ETTs, withdrawal of the LMA was made possible by simply cutting off the pilot balloon. The ETT cuff-inflating mechanism was then repaired by passing a 20 or 22 gauge cannula into the cut end of the inflating tubing. The proximal end of the cannula was then connected to a one-way valve or a three-way stopcock. This technique of cutting off the pilot balloon of the cuffed ETT made it possible to use paediatric cuffed ETTs in exchange for the LMAs tested. The task was easy to perform. Subsequent repair of the cuff-inflation tubing was effective and could withstand high pressures. These findings indicate that it is possible to pass cuffed ETTs through paediatric LMA lumens, which can provide ventilation without gas leaks, unlike uncuffed ETTs.

Numerous cardiac output (CO) monitors have been produced that provide continuous rather than intermittent readings. Bland and Altman has become the standard method for validating their performance against older standards. However, the Bland and Altman method only assesses precision and does not assess how well a device detects serial changes in CO (trending ability). Currently, there is no consensus on how trending ability, or trend analysis, should be performed. Therefore, we performed a literature review to identify articles published between 1997 and 2009 that compared methods of continuous CO measurement. Identified articles were grouped according to measurement technique and statistical methodology. Articles that analyzed trending ability were reviewed with the aim of finding an acceptable statistical method. Two hundred two articles were identified. The most popular methods were pulse contour (69 articles), Doppler (54), bioimpedance (38), and transpulmonary or continuous thermodilution (27). Forty-one articles addressed trending, and of these only 23 provided an in-depth analysis. Several common statistical themes were identified: time plots, regression analysis, Bland and Altman using change in CO (ΔCO), and the 4-quadrant plot, which used direction of change of ΔCO to determine the concordance. This plot was further refined by exclusion of data when values were small. Receiver operating characteristic curves were used to define the exclusion zone. In animal studies, a reliable reference standard such as an aortic flowprobe was frequently used, and regression or time plots could be used to show trending. Clinical studies were more problematic because data collection points were fewer (8-10 per subject). The consensus was to use the 4-quadrant plot with exclusion zones and apply concordance analysis. A concordance rate of >92% when using a 15% zone indicated good trending. A new method of presenting trend data (ΔCO) on a polar plot is proposed. Agreement was shown by the angle with the horizontal axis and ΔCO by the distance from the center. Trending can be assessed by the vertical limits of the data, similar to the Bland and Altman method.

Objectives: Pulmonary dysfunction following lung ischaemia—reperfusion is a well-known phenomenon, which may contribute to post-cardiac surgical morbidity. The process is associated with pulmonary inflammatory response and cellular apoptosis. Early molecular mechanisms leading to such lung injury remain largely unknown. We examined whether lung ischaemia and reperfusion cause significant expression changes in numerousgenesin thelungs involved inpulmonaryapoptosisand othercellularprocessesbyusingoligonucleotidemicroarraysinan experimental model of rodent lung ischaemia—reperfusion injury. Methods: Sprague-Dawley rodents (n = 5 in each group) were anaesthetised and underwent controlled ventilation, with varying durations of warm lung ischaemia (60 and 90 min) followed by a short reperfusion period. The right middle lobe of the lung was harvested. Gene expression changes in the lungs were analysed by rodent DNA microarray chips, and reverse transcription polymerase chain reaction (RT-PCR) performed to validate changes in gene expression. Results:Significant expression changes, with reference to false discovery rate (FDR) controls, were detected in over 80 genes following controlled lung ventilation, and more than 50 were up-regulated more than 2-fold. Lung ischaemia—reperfusion caused expression changes in over 50 additional genes, including many novel genes not previously associated with lung ischaemia—reperfusion. Up-regulated genes identified include those associated with apoptosis, inflammation and cell-cycle control. Conclusions: Large numbers of genes relating to cell metabolism, transcription control, inflammation and apoptosis were significantly up- and down-regulated following controlled ventilation and early lung ischaemia—reperfusion, consistent with previous studies. In addition, novel genes related to lung injury were identified. These genetic signatures provide new insights into early molecular mechanisms of ischaemia— reperfusion lung injury and help refine therapeutic strategies to lessen pulmonary dysfunction following cardiac surgery. # 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

We describe a novel technique, previously applied to small children, for adult one-lung anaesthesia in which a single-lumen endotracheal tube is used with an endobronchial balloon blocker. The main aims of the technique are to reduce the likelihood of cephalad displacement of the balloon into the trachea and to facilitate directional placement of the endobronchial balloon. We present five illustrative cases of one-lung anaesthesia in patients of adult size, in which the endotracheal tube-endobronchial balloon technique was considered preferable to the use of a double-lumen tube technique. The situations included difficult intubation, need for postoperative ventilation, a tortuous trachea and an unexpected need to perform one-lung anaesthesia. The technique involved deliberate placement of the endotracheal tube tip near the carina to block cephalad dislodgement of the blocker. The chance of the balloon blocking the endotracheal tube tip could be further reduced by having the intraluminal endobronchial balloon blocker emerge through the Murphy eye.

Background Current methods of locating the epidural space rely on surface anatomical landmarks and loss-of-resistance (LOR). We are not aware of any data describing real-time ultrasound (US)-guided epidural access in adults. Methods We evaluated the feasibility of performing real-time US-guided paramedian epidural access with the epidural needle inserted in the plane of the US beam in 15 adults who were undergoing groin or lower limb surgery under an epidural or combined spinal–epidural anaesthesia. Results The epidural space was successfully identified in 14 of 15 (93.3%) patients in 1 (1–3) attempt using the technique described. There was a failure to locate the epidural space in one elderly man. In 8 of 15 (53.3%) patients, studied neuraxial changes, that is, anterior displacement of the posterior dura and widening of the posterior epidural space, were seen immediately after entry of the Tuohy needle and expulsion of the pressurized saline from the LOR syringe into the epidural space at the level of needle insertion. Compression of the thecal sac was also seen in two of these patients. There were no inadvertent dural punctures or complications directly related to the technique described. Anaesthesia adequate for surgery developed in all patients after the initial spinal or epidural injection and recovery from the epidural or spinal anaesthesia was also uneventful. Conclusions We have demonstrated the successful use of real-time US guidance in combination with LOR to saline for paramedian epidural access with the epidural needle inserted in the plane of the US beam.

Background: Cardiopulmonary bypass (CPB) is associated with neutrophil activation, pulmonary sequestration, and release of inflammatory mediators leading to pulmonary dysfunction. We investigate the effect of continuous ventilation during cardiopulmonary bypass on neutrophil activation and pulmonary sequestration. Methods: Forty-six patients undergoing coronary artery bypass grafting with cardiopulmonary bypass were prospectively randomized to continuous ventilation and nonventilation groups. Blood samples were collected, and bronchoalveolar lavage (BAL) was performed following induction of anesthesia and at 4 hr after aortic declamping. Differential white cell count was measured, and flow cytometry to determine cell count numbers and quantify CD45 and CD11b leukocyte cell surface adhesion molecule expression was performed on the blood and BAL samples. Results: Twenty-three patients were randomized to standard nonventilated CPB and 23 patients to ventilation throughout CPB. Significant increases in blood and BAL neutrophil numbers were detected at 4 hr following aortic declamping in both groups (Blood: NV p < .0001, V p < .0001; BAL: NV p = .017, V p = .0007). No significant inter-group differences in BAL and blood neutrophil numbers were found. Significantly higher blood neutrophil CD11b meanfluorescent intensity levels werepresent4hrfollowingdeclampingcomparedwithbaselineinbothgroups(NVBlood, p =.021; V Blood p < .0001). No significant inter- or intragroup differences in BAL neutrophil CD11b mean fluorescent intensity levels were found. There was no death or major complication. Conclusions: Cardiopulmonary bypass during coronary artery bypass grafting is associated with increased neutrophil pulmonary sequestration, and blood neutrophil CD11b activation. Continuous ventilation during cardiopulmonary bypass does not significantly reduce neutrophil pulmonary sequestration or activation.

Background A complex inflammatory response associated with the use of cardiopulmonary bypass may ultimately lead to organ dysfunction. We investigate the effect of continuing ventilation during cardiopulmonary bypass on inflammatory reactions and cardiopulmonary function. Methods Fifty patients undergoing cardiopulmonary bypass were prospectively randomized to continuous ventilation and nonventilation groups. Plasma interleukin-8, interleukin-10, matrix metalloproteinase-9, tissue inhibitor metalloproteinase-1, and thromboxane B2 levels were measured preoperatively, at 1, 4, and 6 hours after aortic declamping. Levels of these mediators were also determined in bronchoalveolar lavage preoperatively and four hours after declamping. Seven parameters of cardiopulmonary function, including dynamic compliance and systemic vascular resistance, were recorded during the same time points. Results Plasma interleukin-10 levels were higher at 6 hours and tissue inhibitor metalloproteinase-1 levels were higher at 1 hour after aortic declamping in the continuous ventilation compared with the nonventilation group (p = 0.04 and 0.002, respectively), while bronchoalveolar lavage levels of tissue inhibitor metalloproteinase-1 were also higher in the continuous ventilation group 4 hours after declamping (p = 0.02). Plasma interleukin-8 levels were higher at 4 hours after declamping in the nonventilation group (p = 0.04). Postoperative dynamic compliance was better preserved in continuous ventilation patients than nonventilation patients at 6 hours after declamping (p = 0.0008). Conclusions Continued ventilation during cardiopulmonary bypass results in lesser inflammatory and proteolytic responses, and may better preserve pulmonary function than cardiopulmonary bypass without ventilation.

The effects of flow rheology of non-Newtonian fluids on the time-dependent film-thickness history between non-parallel sliding-squeezing surfaces are studied. On the basis of the power-law fluid model, the hydrodynamic film pressure is obtained from the non-Newtonian dynamic Reynolds-type equation by considering the transient squeezing-action effect. The hydrodynamic film force is then applied to derive the non-linear motion equation of the squeezing part. Using the non-linear transient method, the film-height trajectory of the squeezing part is presented. The results of the present study provide a reference for engineer applications in machine tools, the matched gears, the rolling elements, and the piston-cylinder systems when viscosity-pressure dependence, viscosity-temperature variation, and elastic deformations of the contacting surfaces are neglected.

A four-hour integrated teaching session on clinical decision analysis has been developed and introduced as part of the Life Long Learning Skills course for medical students at The Chinese University of Hong Kong. The feasibility and effectiveness of teaching the principles and practice of clinical decision analysis to final-year undergraduate medical students was evaluated. One hundred and thirty-two students were randomly assigned to medical (intervention) and surgical rotations (control) and were assessed two weeks before and three weeks following a teaching session. The students' performance was assessed in response to 10 A-type multiple choice question items that incorporated various clinical scenarios requiring decision making and interpreting cost-effectiveness ratios and sensitivity analysis graphs. More students in the intervention group improved their overall performance scores compared with those in the control group (23.4% vs. 7.4%; 16.1% difference; 95% confidence interval [CI], 3.8-28.5%; p = 0.01). Improvements were in interpretation of decision making (22.2% difference; 95% CI, 10.1-34.4%; p0.001). No improvements were seen for calculating cost-effectiveness ratios or interpreting sensitivity analysis graphs. The overall educational intervention was well received by students and effective in improving students' clinical decision analysis skills under simulated conditions.

Background: Remote ischemic preconditioning is a simple therapy that may reduce cardiac and kidney injury. We undertook a randomized controlled trial to evaluate the effect of this therapy on markers of heart and kidney injury after cardiac surgery. Methods: Patients at high risk of death within 30 days after cardiac surgery were randomly assigned to undergo remote ischemic preconditioning or a sham procedure after induction of anesthesia. The preconditioning therapy was three 5-minute cycles of thigh ischemia, with 5 minutes of reperfusion between cycles. The sham procedure was identical except that ischemia was not induced. The primary outcome was peak creatine kinase–myocardial band (CK-MB) within 24 hours after surgery (expressed as multiples of the upper limit of normal, with log transformation). The secondary outcome was change in creatinine level within 4 days after surgery (expressed as log-transformed micromoles per litre). Patient-important outcomes were assessed up to 6 months after randomization. Results: We randomly assigned 128 patients to remote ischemic preconditioning and 130 to the sham therapy. There were no significant differences in postoperative CK-MB (absolute mean difference 0.15, 95% confidence interval [CI] −0.07 to 0.36) or creatinine (absolute mean difference 0.06, 95% CI −0.10 to 0.23). Other outcomes did not differ significantly for remote ischemic preconditioning relative to the sham therapy: for myocardial infarction, relative risk (RR) 1.35 (95% CI 0.85 to 2.17); for acute kidney injury, RR 1.10 (95% CI 0.68 to 1.78); for stroke, RR 1.02 (95% CI 0.34 to 3.07); and for death, RR 1.47 (95% CI 0.65 to 3.31). Interpretation: Remote ischemic precnditioning did not reduce myocardial or kidney injury during cardiac surgery. This type of therapy is unlikely to substantially improve patient-important outcomes in cardiac surgery. Trial registration: ClinicalTrials.gov, no. NCT01071265.

The availability of less expensive and smaller ultrasound machines has enabled the use of ultrasound in virtually all major medical/surgical disciplines. Some medical schools have incorporated point-of-care ultrasound training into their undergraduate curriculum, whereas many postgraduate programs have made ultrasound training a standard. The Chinese University of Hong Kong has charged its Department of Anaesthesia and Intensive Care to spearhead the introduction of ultrasound into the final-year medical curriculum by introducing handheld transthoracic echocardiography as part of perioperative assessment.All 133 final-year students completed a 2-week anesthesia rotation, which began with a half-day session consisting of a lecture and hands-on practice session during which they learned 9 basic transthoracic echocardiography views using 4 basic ultrasound probe positions.Each student was required to perform a transthoracic echocardiography-examine under supervision of 1 patient/week for 2 weeks, and their results were compared against that of the supervisor's. Most patients were elective cardiac surgery patients. One long question on transthoracic echocardiography was included in their end-of-year surgery examination paper. Students provided feedback on their experience.Most students learned the basic transthoracic echocardiography views fairly efficiently and had variable, though generally favorable, success rates in identifying obvious cardiac anomalies, including use of color Doppler. A few common mistakes were identified but were easily correctable. Logistics for mobilizing enough bedside supervision were challenging. Students reported positive feedback on the teaching initiative.We were able to execute a successful short training course on transthoracic echocardiography during the final-year medical degree anesthesia rotation. Our initiative may set an example for other clinical departments to design similar courses pertinent to their specialties and syllabuses.

Currently, there are no quantitative data on the echo texture of a peripheral nerve. This study was designed to objectively compare the differences in the echo texture of the median nerve in the young and the elderly.The median nerves of 10 healthy young volunteers (30 years old; group Y) and 10 elderly patients undergoing lower limb surgery (60 years old; group E) were scanned at the mid forearm by a standardized protocol. The echo texture of a normalized median nerve image was analyzed for the echo intensity and spatial distribution of pixels. Noise in the image was reduced by using a median filter, and thresholding was performed thereafter. In the resultant binary image, the cross-sectional area, echo intensity, white area index, and black area index of the median nerve were determined by computerized texture analysis.The mean cross-sectional area of the median nerve in group E was significantly smaller than that in group Y (P = .002). The mean echo intensity and white area index in group E were significantly higher than those in group Y (P= .002 and .012). The mean black area index in group E was correspondingly significantly lower than that in group Y (P = .012). In group Y, the mean white area index was significantly lower than the black area index (P = .006) but not in group E (P = .213).There are significant differences in the echo texture of the median nerve between the young and the elderly. These differences may be due to age-related changes in the relative proportion of neural fascicles and connective tissue within the nerve.

Recombinant activated factor VII (rFVIIa) is a powerful prohaemostatic agent that theoretically predisposes to thrombosis after peripheral vascular surgery. We report the use of rFVIIa to reduce bleeding in a patient after axillofemoral bypass grafting for ruptured aorto-iliac pseudoaneurysm. Despite the increased risk of thrombosis, the patient made an uneventful recovery with preserved graft patency. The favourable result suggests that rFVIIa should be considered even in vascular surgical patients, if the risks of continued bleeding outweigh those of thrombosis. Better risk estimation is only possible if reports of rFVIIa use in vascular patients continue to appear and through controlled trials.

This prospective before-and-after observational study investigated the effect of upper airway anaesthesia on dynamic airflow. Six consenting ASA 1 adults, all authors of this study, underwent a series of Spirometric measurements before and after topical anaesthesia of the upper airway using lignocaine. Peak inspiratory flow rate, forced inspiratory flow between 25% and 75% of the maximum inhaled volume, forced expiratory volume at 1 second, and forced vital capacity in the supine and sitting positions were measured. The measured inspiratory parameters were significantly reduced after lignocaine topical anaesthesia of the upper airway. Expiratory flow parameters were not affected. We conclude that topical anaesthesia of the upper airway leads to dynamic inspiratory airflow limitation.

The aim of present study is to investigate the effect of chord-wise flexure amplitude on unsteady aerodynamic characteristics for a flapping airfoil with various combinations of Reynolds number and reduced frequency. Unsteady, viscous flows over a single flexible airfoil in plunge motion are computed using conformal hybrid meshes. The dynamic mesh technique is applied to illustrate the deformation modes of the flexible flapping airfoil. In order to investigate the influence of the flexure amplitude on the aerodynamic performance of the flapping airfoil, the present study considers eight different flexure amplitudes ( a 0 ) ranging from 0 to 0.7 in intervals of 0.1 under conditions of Re=10 4 , reduced frequency k =2, and dimensionless plunge amplitude h 0 =0.4. The computed unsteady flow fields clearly reveal the formation and evolution of a pair of leading edge vortices along the body of the flexible airfoil as it undergoes plunge motion. Thrust-indicative wake structures are generated when the flexure amplitude of the airfoil is less than 0.5 of the chord length. An enhancement in the propulsive efficiency is observed for a flapping airfoil with flexure amplitude of 0.3 of the chord length. This study also calculates the propulsive efficiency and thrust under various Reynolds numbers and reduced frequency conditions. The results indicate that the propulsive efficiency has a strong correlation with the reduced frequency. It is found that the flow conditions which yield the highest propulsive efficiency correspond to Strouhal number St of 0.255.

Thoracic sympathectomy remains an effective method for treatment of palmar hyperhidrosis refractory to other conservative forms of management. The procedure has become more acceptable following the introduction of the minimally invasive technique using video-assisted thoracic surgery (VATS). More recently, single-port VATS has gained popularity as an alternative approach to performing sympathectomy. We report on our experience and early results of single-port bilateral VATS sympathectomy using the Vasoview(®) (Maquet Inc., Rastatt, Germany) device at our institute.All patients who underwent VATS sympathectomy for primary palmar hyperhidrosis between June 2011 and March 2012 were recruited into this prospective study. Patients' demographics and intraoperative and postoperative outcomes were collected. Effectiveness of the procedure, postoperative pain, duration of hospital stay, and complications were also measured.Sixteen patients underwent Vasoview bilateral VATS sympathectomy for severe palmar hyperhidrosis. Mean age was 23.8 years (range, 17-36 years), and mean operative time to complete the bilateral procedure was 56 minutes (range, 42-81 minutes). The procedure was successfully completed in all patients without the need to enlarge the incision or convert. Postoperatively, there was no mortality and no residual palmar hyperhidrosis. Mean postoperative stay was 0.9 days (range, 0.7-1.9 days). The mean visual analog pain score at discharge was 1.8 (range, 1.2-3.4).Single-port Vasoview sympathectomy for treatment of severe palmar hyperhidrosis is technically feasible and safe with satisfactory immediate and early results. Intermediate and long-term follow-up is required to monitor recurrence or late complications. Future studies are warranted to compare Vasoview single-port and other minimal invasive VATS approaches.

Summary Continuous central pressure monitoring and simultaneous continuous infusion via the same central venous catheter are sometimes necessary. Based on theoretical calculations and experimental measurements, we have determined that pressure monitoring is essentially unaffected if the continuous infusion rate is 50 ml.h−1 or less for an adult and a paediatric central catheter. At rates > 200 ml.h−1, the central venous pressure is exaggerated by up to 4 mmHg and 8 mmHg for the adult and paediatric catheters, respectively.

Background Animal and volunteer studies indicate that ropivacaine is associated with less neurologic and cardiac toxicity than bupivacaine. Ropivacaine may offer advantages when used for thoracic paravertebral block. This study was designed to describe the pharmacokinetics of ropivacaine after thoracic paravertebral block. Methods Twenty female patients undergoing elective unilateral breast surgery were randomly assigned to receive a single bolus thoracic paravertebral injection of 2 mg/kg ropivacaine, with or without 5 mug/ml epinephrine. Simultaneous arterial and venous blood samples were obtained for plasma ropivacaine assay. Data were analyzed with NONMEM, using two possible absorption models: conventional first-order absorption and absorption following the inverse gaussian density function. Results Epinephrine reduced the peak plasma concentrations and delayed the time of peak concentration of ropivacaine in both the arterial and venous blood. The time course of drug input into the systemic circulation was best described by two inverse gaussian density functions. The median bioavailability of the rapid component was approximately 20% higher when epinephrine was not used. The mean absorption times were 7.8 min for the rapid absorption phase and 697 min for the slow absorption phase, with wide dispersion of the absorption function for the acute phase. The half-time of arterial-venous equilibration was 1.5 min. Conclusion The absorption of ropivacaine after thoracic paravertebral block is described by rapid and slow absorption phases. The rapid phase approximates the speed of intravenous administration and accounts for nearly half of ropivacaine absorption. The addition of 5 mug/ml epinephrine to ropivacaine significantly delays its systemic absorption and reduces the peak plasma concentration.

Hemorrhage is a major cause of trauma deaths. Coagulopathy exacerbates hemorrhage and is commonly seen during major trauma resuscitation, suggesting that current practice of coagulation factor transfusion is inadequate. Reversal of coagulopathy involves normalization of body temperature, elimination of the causes of disseminated intravascular coagulation (DIC), and transfusion with fresh-frozen plasma (FFP), platelets, and cryoprecipitate. Transfusion should be guided by clinical factors and laboratory results. However, in major trauma, clinical signs may be obscured and various factors conspire to make it difficult to provide the best transfusion therapy. Existing empiric transfusion strategies for, and prevailing teachings on, FFP transfusion appear to be based on old studies involving elective patients transfused with whole blood and may not be applicable to trauma patients in the era of transfusion with packed red blood cells (PRBCs). Perpetuation of such concepts is in part responsible for the common finding of refractory coagulopathy in major trauma patients today. In this review, we argue that coagulopathy can best be avoided or reversed when severe trauma victims are transfused with at least the equivalent of whole blood in a timely fashion.

To report a case of complete upper airway obstruction after topicalization with lidocaine in a completely conscious patient with partial upper airway obstruction. A 69-yr-old man with a history of neck cancer and radiation presented for resection of recurrent neck tumour. No preoperative sedation was given. He had inspiratory and expiratory stridor but had no history of aspiration or swallowing problem. Phonation was distorted but effective. The surgeon was reluctant to perform an awake tracheostomy under local anesthesia. In preparation for a fibrescope-assisted orotracheal intubation, the non-sedated patient was given topical upper airway lidocaine during which he developed total airway obstruction and hypoxemia. He was immediately intubated with a fibrescope. His vocal cords were not edematous although the supraglottic structures appeared to be. The vocal cords were abducted and their movement was limited and not paradoxical. Tumour resection was uneventful upon successful tracheal intubation and general anesthesia. Tracheostomy at the end of the case was difficult, as expected. The patient tolerated the procedures and regained consciousness with no neurologic sequelae. Dynamic airflow limitation associated with local anesthesia of the upper airway may lead to complete upper airway obstruction in a compromised airway. The main cause may be the loss of upper airway muscle tone, exacerbated by deep inspiration during panic.

Postthoracotomy pain syndrome is relatively common and is seen in approximately 50% of patients after thoracotomy. It is a chronic condition, and about 30% of patients might still experience pain 4 to 5 years after surgery. In the majority of patients pain is usually mild and only slightly or moderately interferes with normal daily living. In a small subset of patients pain can be severe and can be described as a true disability to the extent that these patients are incapacitated. The exact mechanism for the pathogenesis of PTPS is still not clear, but cumulative evidence suggests that it is a combination of neuropathic and nonneuropathic (myofascial) pain. Trauma to the intercostal nerve during thoracotomy is the most likely cause. Because pain does not cause disability in the majority of patients, management is usually conservative. If pain is causing disability then multidisciplinary pain management involving the pain specialist, social worker, physical therapist, and a psychologist is required. It is mandatory to exclude recurrence of disease or malignancy as a cause for the pain prior to initiating treatment. As with most forms of neuropathic pain, treatment of PTPS is also difficult and patients might require more than one form of therapy to control pain and reduce disability. Based on current evidence, it is not possible to draw any firm conclusion regarding whether any form of analgesic or surgical technique can influence the generation of PTPS. Preemptive analgesia initiated prior to surgery shows promise and might help reduce the incidence of PTPS. Scientific evidence is steadily growing but there is still a need for large, prospective, randomized trials evaluating PTPS. Until more is known about this condition and how to prevent the central and peripheral nervous system changes that produce long-term pain after thoracotomy, patients must be warned preoperatively about the possibility of developing PTPS and how it might affect their quality of life after surgery. In addition, measures such as selecting the least traumatic and painful surgical approach, avoiding intercostal nerve trauma, and adopting an aggressive multimodal perioperative pain management regimen commenced before the surgical incision should be performed to prevent postthoracotomy pain syndrome.

Objective To evaluate, by systematic review, the efficacy of heliox on respiratory mechanics and outcomes in patients with acute asthma. Methods The search strategy included searching electronic databases (MEDLINE, EMBASE, and The Cochrane Library) and the references of relevant articles. Study quality was assessed based on allocation concealment. Randomized controlled trials (RCTs) comparing heliox to an air-oxygen mixture (airO 2 ) as an adjunct treatment in patients with acute asthmatic attacks were analyzed. For the qualitative portion of the analysis, all reports of the use of heliox in patients with acute asthma were included. Results Four RCTs (n = 278) were found to have a common respiratory parameter (peak expiratory flow rate as a percentage of predicted) suitable for meta-analysis. Within the 92% confidence interval (CI), there was a small benefit with the use of heliox compared to airO 2 (weighted mean difference, + 3%; 95% CI, − 2 to + 8%). There was also a slight improvement in the dyspnea index (weighted mean difference, 0.60; 95% CI, 0.04 to 1.16) with the use of heliox over airO 2 . Overall, five RCTs, one nonrandomized unblinded parallel trial, one retrospective case-matched control trial, three case series, and one case report had results in favor of heliox; one RCT and one case series showed no improvement with heliox; one RCT showed a possible detrimental effect with heliox; and 1 small RCT was inconclusive. Most investigators did not prevent entrainment of room air during heliox use or compensate for the lower nebulizing efficiency of heliox. Conclusion Based on surrogate markers, heliox may offer mild-to-moderate benefits in patients with acute asthma within the first hour of use, but its advantages become less apparent beyond 1 h, as most conventionally treated patients improve to similar levels, with or without it. The effect of heliox may be more pronounced in more severe cases. There are insufficient data on whether heliox can avert tracheal intubation, or change intensive care and hospital admission rates and duration, or mortality.

Study objective: To evaluate the efficacy of a continuous thoracic paravertebral infusion of bupivacaine for pain management in patients with unilateral multiple fractured ribs (MFR). Design: Prospective nonrandomized case series. Setting: Multidisciplinary tertiary hospital. Patients: Fifteen patients with unilateral MFR. Interventions: Insertion of a catheter into the thoracic paravertebral space. We administered an initial injection of 0.3 mL/kg (1.5 mg/kg) bupivacaine 0.5% with 1:200,000 epinephrine followed 30 min later by an infusion of bupivacaine 0.25% at 0.1 to 0.2 mL/kg/h for 4 days. Measurements and results: The following parameters were measured during the initial assessment before thoracic paravertebral block (TPVB), 30 min after the initial injection, and during follow-up on day 1 and day 4 after commencing the infusion of bupivacaine: visual analog pain score at rest and during coughing; respiratory rate; arterial oxygen saturation (Sa o 2 ); bedside spirometry ( ie , FVC, FEV 1 , FEV 1 /FVC ratio, and peak expiratory flow rate [PEFR]); arterial blood gas measurements; and O 2 index ( ie , Pa o 2 /fraction of inspired oxygen ratio). There were significant improvements in pain scores (at rest, p = 0.002; during coughing, p = 0.001), respiratory rate (p o 2 (p = 0.04), and O 2 index (p = 0.01) 30 min after the initial injection, which were sustained for the 4 days that the thoracic paravertebral infusion was in use (p co 2 did not change significantly after the initial injection, but on day 4 it was significantly lower than the post-TPVB value (p = 0.04). One patient had an inadvertent epidural injection, and another developed transient ipsilateral Horner syndrome with sensory changes in the arm. No patient exhibited clinical signs of inadvertent intravascular injection or local anesthetic toxicity. Conclusion: Our results confirmed that continuous thoracic paravertebral infusion of bupivacaine is a simple and effective method of providing continuous pain relief in patients with unilateral MFR. It also produced a sustained improvement in respiratory parameters and oxygenation.

UNLABELLED The prothrombin time (PT) is useful for identifying coagulation factor deficits after cardiopulmonary bypass (CPB). However, long processing times and the need for fresh frozen plasma (FFP) to be thawed cause delays in factor replacement. We hypothesized that, by treating with heparinase, blood sampled toward the end of CPB can provide PT results that help to determine the requirement for FFP after CPB. Laboratory delays can be eliminated with point-of-care monitors. We studied 158 adults undergoing nonemergent cardiac surgery. Blood taken before separation from CPB was mixed with heparinase, and PT was measured in the laboratory with a HemoTec timer. Agreements between these results and laboratory measurements of blood taken after systemic protamine were compared by using Bland and Altman plots with the threshold of +/-1.0 s. We found that the laboratory PT measurements during CPB versus after CPB were compara-ble, but the limits of agreement exceeded these thresholds. Similarly, there was unsatisfactory agreement between the HemoTec and laboratory PT results measured before, during, and after CPB. For each PT measured during CPB, the corresponding confidence interval for the postprotamine PT was calculated. During CPB, a laboratory PT of or =18 s suggests a > or =83% or > or =93% probability of not requiring or potentially requiring, respectively, FFP after CPB. We conclude that the majority of PT measurements obtained from blood taken before weaning from CPB and treated in vitro with heparinase was associated with a high probability of whether or not FFP would be needed after CPB. IMPLICATIONS Coagulation dysfunction after cardiopulmonary bypass may contribute to bleeding. Obtaining coagulation tests and fresh frozen plasma requires time and delays treatment in patients who need fresh frozen plasma. We have devised a technique to provide early estimation of postbypass coagulation status.

Severe bleeding from injury to abdominal wall blood vessels during minor laparoscopic procedures can occur. Two cases of shock presenting several hours after surgery are presented.

To report the use of a combined paravertebral lumbar plexus and parasacral sciatic nerve block for reduction of hip fracture in an elderly patient with severe aortic stenosis.In an 87-yr-old lady with severe aortic stenosis and fracture of the right trochanter due to a fall, a combined right-sided paravertebral lumbar plexus and parasacral sciatic nerve block was used successfully for operative reduction of the fracture. A moderate amount of phenylephrine was required to maintain adequate systemic blood pressure despite the largely unilateral nature of the blocks.Combined paravertebral lumbar plexus and parasacral sciatic nerve block can be a viable alternative to general anesthesia and epidural or spinal block for hip surgery in patients with severe aortic stenosis.

Omission of a confidence interval (CI) associated with the risk of a serious complication can lead to inaccurate interpretation of risk data. The calculation of a CI for a risk or a single proportion typically uses the familiar Gaussian (normal) approximation. However, when the risk is small, "exact" methods or other special techniques should be used to avoid overshooting (risks that include values outside of [0,1]) and zero width interval degeneration. Computer programs and simple equations are available to construct CIs reasonably accurately. In the special case in which the complication has not occurred, the risk estimated with 95% confidence is no worse than 3/n, where n is the number of trials.

Heliox has a lower density than oxygen and nitrogen, and can improve ventilation rapidly in patients with critical upper airway obstruction. The choice of the best helium:oxygen ratio depends on whether the predominant problem is hypercarbia or hypoxia. In the former situation, 80% helium should be used, and in the latter, 100% oxygen is appropriate.

Intrathecal local anesthetic maldistribution is a well-known cause of spinal anesthesia failure (SAF). This could potentially result in sensory blockade restricted to the sacral dermatomes. We sought to determine the overall incidence of SAF and the role of sacral dermatomes in differentiating between total and partial failures. Of the 3111 spinals prospectively examined, 194 (6.2%) were classified as failures. Of the 72 presumed total failures based on the initial assessment, evaluation of the sacral dermatomes revealed sensory blockade in 32 (44%; 95% confidence interval, 32.7%-56.6%). Sacral dermatome assessment after SAF may be important in safely guiding subsequent anesthetic management.

The global incidence of out-of-hospital cardiac arrest is 213.1 (SD ± 177) per 100 000 population.1 More than 20 000 people have out-of-hospital cardiac arrest each year in Canada, where cardiopulmonary resuscitation (CPR) rates rarely exceed 25%.2 The latest (2010) guidelines from the

Patients undergoing breast cancer surgery frequently experience chronic postoperative pain. The primary objective of this randomized study was to determine if thoracic paravertebral block (TPVB) reduced the incidence of chronic pain after a modified radical mastectomy (MRM) when compared with general anesthesia (GA).One hundred eighty women undergoing MRM were randomized to 1 of 3 study groups: group 1: standardized GA, group 2: GA with a single-injection TPVB and placebo paravertebral infusion, and group 3: GA with a continuous TPVB. Outcomes assessed postoperatively included acute postoperative pain and analgesic consumption and, at 3 and 6 months, the incidence and severity of chronic pain and physical and mental health-related quality of life (HRQOL).There was no significant difference in the incidence of chronic pain at 3 months (P = 0.13) and 6 months (P = 0.79) after the MRM between the study groups. The relative risk of developing chronic pain (P = 0.25) was also similar between the groups. There was no difference in acute pain (P = 0.22) or postoperative analgesic consumption (P = 0.67) between the groups. Nevertheless, differences were observed in chronic pain-related secondary outcome variables. The TPVB groups reported lower chronic pain scores (P0.05), exhibited fewer symptoms and signs of chronic pain (P ≤ 0.01), and also experienced better physical and mental HRQOL than did the GA group. Chronic pain scores also decreased with time in all study groups (P0.05).There is no significant difference in the incidence or relative risk of chronic pain at 3 and 6 months after an MRM when TPVB is used in conjunction with GA. Nevertheless, patients who receive a TPVB report less severe chronic pain, exhibit fewer symptoms and signs of chronic pain, and also experience better physical and mental HRQOL.

Background and Objectives The need for continual neurological assessment in patients with lumbar spinal injury poses a challenge for effective management of pain associated with multiple fractured ribs. Two cases are presented to illustrate the benefits of using thoracic paravertebral block to control the pain of multiple fractured ribs without compromising the ongoing neurological assessment. Case Report Thoracic paravertebral block was used in 2 patients with concomitant multiple fractured ribs and lumbar spinal injury. Case 2 also had a head injury and there was moderate coagulopathy. The thoracic paravertebral catheter was placed in the upper thoracic region and radiological imaging was used to delineate spread before the injection of relatively small volumes (10 to 15 mL) of local anesthetic. In case 1, the thoracic paravertebral block produced ipsilateral segmental thoracic anesthesia, providing excellent pain relief for the fractured ribs. It also spared the lumbar and sacral nerve roots, preserving neurological function in the lower extremities and bladder sensation. In case 2, effective analgesia without systemic sedation and opioids resulted in the patient regaining consciousness, which allowed continuous assessment of central and peripheral neurological function. Conclusion Thoracic paravertebral block is an option for managing pain associated with multiple fractured ribs in the presence of concomitant lumbar spinal injury requiring continual neurological assessment.

During trauma resuscitation involving massive transfusion, the best fresh-frozen plasma to packed red blood cells ratio is unknown. No randomised controlled trial (RCT) is available on this subject, although there are plenty of observational studies suggesting that the ratio should be about 1:1. This ratio also makes more physiological sense, and we suggest that in patients with massive and ongoing bleeding, it is a sensible strategy with which to start resuscitation.