S.J. Howell

Efficacy and safety of different techniques of paravertebral block for analgesia after thoracotomy: a systematic review and metaregression

Various techniques and drug regimes for thoracic paravertebral block (PVB) have been evaluated for post-thoracotomy analgesia, but there is no consensus on which technique or drug regime is best. We have systematically reviewed the efficacy and safety of different techniques for PVB. Our primary aim was to determine whether local anaesthetic (LA) dose influences the quality of analgesia from PVB. Secondary aims were to determine whether choice of LA agent, continuous infusion, adjuvants, pre-emptive PVB, or addition of patient-controlled opioids improve analgesia. Indirect comparisons between treatment arms of different trials were made using metaregression. Twenty-five trials suitable for metaregression were identified, with a total of 763 patients. The use of higher doses of bupivacaine (890-990 mg per 24 h compared with 325-472.5 mg per 24 h) was found to predict lower pain scores at all time points up to 48 h after operation (P=0.006 at 8 h, P=0.001 at 24 h, and P<0.001 at 48 h). The effect-size estimates amount to around a 50% decrease in postoperative pain scores. Higher dose bupivacaine PVB was also predictive of faster recovery of pulmonary function by 72 h (effect-size estimate 20.1% more improvement in FEV1, 95% CI 2.08%-38.07%, P=0.029). Continuous infusions of LA predicted lower pain scores compared with intermittent boluses (P=0.04 at 8 h, P=0.003 at 24 h, and P<0.001 at 48 h). The use of adjuvant clonidine or fentanyl, pre-emptive PVB, and the addition of patient-controlled opioids to PVB did not improve analgesia. Further well-designed trials of different PVB dosage and drug regimes are needed.

Pumpless extracorporeal carbon dioxide removal for life-threatening asthma.

Objective:To report the use of pumpless extracorporeal carbon dioxide removal in two cases of acute severe asthma. Design:Case reports. Setting:Adult general intensive care unit, Leeds General Infirmary, Leeds, UK. Patients:A 74-yr-old male and 52-yr-old female with life-threatening asthma developed progressive hypercapnia and severe acidosis that proved nonresponsive to all other therapies. Intervention:Initiation of extracorporeal arteriovenous carbon dioxide removal using the Novalung device (Novalung GmbH, Lotzenäcker 3, D-72379 Hechingen, Germany). Main Results:The addition of extracorporeal carbon dioxide removal to mechanical ventilation corrected hypercapnia and acidosis, allowing reduction of other supportive measures. In both cases, adequate gas exchange was maintained until their underlying condition improved sufficiently for device removal. The two patients were subsequently weaned from mechanical ventilation and made a full recovery. Conclusions:Extracorporeal carbon dioxide removal proved to be a valuable adjunct to mechanical ventilation and other medical treatment.

Effect of supervised aerobic exercise rehabilitation on physical fitness and quality-of-life in survivors of critical illness: an exploratory minimized controlled trial (PIX study)

Background Evidence is limited for the effectiveness of interventions for survivors of critical illness after hospital discharge. We explored the effect of an 8-week hospital-based exercise-training programme on physical fitness and quality-of-life. Methods In a parallel-group minimized controlled trial, patients were recruited before hospital discharge or in the intensive care follow-up clinic and enrolled 8–16 weeks after discharge. Each week, the intervention comprised two sessions of physiotherapist-led cycle ergometer exercise (30 min, moderate intensity) plus one equivalent unsupervised exercise session. The control group received usual care. The primary outcomes were the anaerobic threshold (in ml O2 kg−1 min−1) and physical function and mental health (SF-36 questionnaire v.2), measured at Weeks 9 (primary time point) and 26. Outcome assessors were blinded to group assignment. Results Thirty patients were allocated to the control and 29 to the intervention. For the anaerobic threshold outcome at Week 9, data were available for 17 control vs 13 intervention participants. There was a small benefit (vs control) for the anaerobic threshold of 1.8 (95% confidence interval, 0.4–3.2) ml O2 kg−1 min−1. This advantage was not sustained at Week 26. There was evidence for a possible beneficial effect of the intervention on self-reported physical function at Week 9 (3.4; −1.4 to 8.2 units) and on mental health at Week 26 (4.4; −2.4 to 11.2 units). These potential benefits should be examined robustly in any subsequent definitive trial. Conclusions The intervention appeared to accelerate the natural recovery process and seems feasible, but the fitness benefit was only short term. Clinical trial registration Current Controlled Trials ISRCTN65176374 (http://www.controlled-trials.com/ISRCTN65176374).

Comparison of stroke volume and fluid responsiveness measurements in commonly used technologies for goal-directed therapy

STUDY OBJECTIVE To compare stroke volume (SV) and preload responsiveness measurements from different technologies with the esophageal Doppler monitor (EDM). DESIGN Prospective measurement study. SETTING Operating room. PATIENTS 20 ASA physical status 3 patients undergoing vascular, major urological, and bariatric surgery. INTERVENTIONS Subjects received fluids using a standard Doppler protocol of 250 mL of colloid administered until SV no longer increased by >10%, and again when the measured SV decreased by 10%. MEASUREMENTS Simultaneous readings of SV, stroke volume variation (SVV) and pulse pressure variation (PPV) from the LiDCOrapid, and SVV from the FloTrac/Vigileo were compared with EDM measurements. The pleth variability index (PVI) also was recorded. MAIN RESULTS No correlation was seen in percentage SV change as measured by either the LiDCOrapid (r=0.05, P=0.616) or FloTrac (r=0.09, P= 0.363) systems compared with the EDM. Correlation was present between the LiDCOrapid and FloTrac (r=0.515, P<0.0001). Percentage error compared with the EDM was 81% for the FloTrac and 90% for the LiDCOrapid. SVV as measured by LiDCOrapid differed for fluid responders and nonresponders (10% vs 7%; P=0.021). Receiver operator curve analysis to predict a 10% increase in SV from the measured variables showed an area under the curve of 0.57 (95% CI 0.43-0.72) for SVV(FloTrac), 0.64 (95% CI 0.52-0.78) for SVV(LiDCO), 0.61 (95% CI 0.46 -0.76) for PPV, and 0.59 (95% CI 0.46 -0.71) for PVI. CONCLUSIONS Stroke volume as measured by the FloTrac and LiDCOrapid systems does not correlate with the esphageal Doppler, has poor concordance, and a clinically unacceptable percentage error. The predictive value of the fluid responsiveness parameters is low, with only SVV measured by the LiDCOrapid having clinical utility.

Measuring outcomes after major abdominal surgery during hospitalization: reliability and validity of the Postoperative Morbidity Survey

BackgroundMeasurement of outcomes after major abdominal surgery has traditionally focused on mortality, however the low incidence in elective surgery makes this measure a poor comparator. The Postoperative Morbidity Survey (POMS) prospectively assesses short-term morbidity, and may have clinical utility both as a core outcome measure in clinical trials and quality of care. The POMS has been shown to be a valid outcome measure in a mixed surgical population, however it has not been studied in patients undergoing major abdominal surgery. This study assessed the inter-rater reliability and validity of the POMS in patients undergoing major abdominal surgery.MethodsPatients undergoing elective major abdominal surgery were visited on postoperative day 1 until discharge by two novice observers who administered the POMS in order to assess inter-rater reliability. Subjects who had previously had the POMS performed prospectively on postoperative days 3 and 5 were identified from a database. The pattern and prevalence of morbidity was analyzed against hospital length of stay (LOS) in order to validate the POMS in this patient group.ResultsFifty one patients were recruited to the inter-rater reliability study giving a total of 263 POMS assessments. Inter-rater reliability showed a 97.7% agreement with a κ coefficient of 0.912 (95% CI: 0.842 to 0.982). On domain analysis percentage agreement was lowest in the gastrointestinal domain (87.5%), whilst correlation was lowest in the wound (κ: 0.04; 95% CI: −1.0 to 1.0) and hematological domains (κ: 0.378; 95% CI: 0.035 to 0.722). All other domains showed at least substantial agreement. POMS assessments were analyzed for postoperative days 3 (n = 258) and 5 (n = 362). The absence or presence of morbidity as measured by the POMS was associated with a hospital LOS of 6 (IQR: 4 to 7) vs. 11 (IQR: 8 to 15) days on postoperative day 3 (P <0.0001), and 7 (IQR: 6 to 10) vs. 13 (IQR: 9 to 19) days on postoperative day 5 (P <0.0001). The presence of any morbidity on postoperative day 5 conferred an odds ratio for a prolonged hospital LOS of 11.9 (95% CI: 5.02 to 11.92).ConclusionsThis study shows that the POMS is both a reliable and valid measure of short-term postoperative morbidity in patients undergoing major abdominal surgery.

Meta-analysis of prospective trials determining the short- and mid-term effect of elective open and endovascular repair of abdominal aortic aneurysms on quality of life.

Repair of an abdominal aortic aneurysm (AAA) is undertaken to prevent rupture. Intervention is by either open repair (OR) or a more minimally invasive endovascular repair (EVAR). Quality‐of‐life (QoL) analysis is an important health outcome and a number of single studies have assessed QoL following OR and EVAR. This was a meta‐analysis of published studies to assess the effect of an intervention on QoL in patients with an AAA.

Diagnosing postoperative neuropathic pain: a Delphi survey

BACKGROUND Although postoperative pain is traditionally considered to be nociceptive in origin, a proportion of patients experience a significant neuropathic component to their pain experience. Diagnosing neuropathic pain in this setting is challenging, and there are no published guidelines or screening tools designed for use in the immediate postoperative setting. We hypothesized that acute pain specialists were diagnosing a neuropathic component to acute pain, and this study aimed to obtain an expert agreed list of pain characteristics that could be used to aid diagnosis. METHODS A three-round Internet-based Delphi survey of acute pain specialists was used to generate a list of acute neuropathic pain characteristics, and achieve consensus on the importance of each item. Items were ranked on a 1-10 scale of importance, with a median score of ≥ 7 considered important and an inter-quartile range of ≤ 3 indicative of consensus. Cronbachs α was used to investigate internal consistency. RESULTS Twenty-four items were generated by round 1 of the Delphi survey. Fourteen panellists participated in round 2, and 10 in round 3. After round 3, consensus of opinion was achieved for 13 items, with nine rated as important in the diagnosis of acute neuropathic pain. CONCLUSIONS The Delphi survey suggests that neuropathic pain in the immediate postoperative period is diagnosed in a different way to chronic neuropathic pain, with items such as response to medications considered more useful than signs such as those representing autonomic changes.

Cardiopulmonary exercise testing: a review of methods and applications in surgical patients

Cardiopulmonary exercise (CPX) testing has a number of medical applications, including the assessment of heart failure and the investigation of unexplained breathlessness. Over the past decade, it has become an important preoperative assessment tool to evaluate functional capacity and predict outcomes in patients undergoing both cardiac and noncardiac surgery. A CPX test is an incremental exercise test during which respiratory variables, including oxygen uptake and carbon dioxide excretion are measured and the ECG is monitored. Among the variables reported from a CPX test are oxygen uptake at anaerobic threshold and peak oxygen uptake. A limited functional capacity as indicated by a low anaerobic threshold or VO2peak has been shown to be associated with an increased incidence of perioperative complications in a number of surgical settings. Other reported variables, including the ventilatory equivalents for oxygen (VE/VO2) and carbon dioxide (VE/VCO2) and the millilitre of oxygen delivered per heartbeat or oxygen pulse [VO2/heart rate (HR)] may give indications as to the reasons for exercise limitation. ECG evidence of myocardial ischaemia with increasing workload is also an important indicator of increased perioperative risk. As a noninvasive, low-risk, test of the integrated responses to increasing cardiovascular stress, anaesthesiologists involved in preoperative assessment should have an understanding of its current uses and test outcomes. This review presents the physiological basis for CPX testing, methodology, advantages over other preoperative tests of cardiovascular function and guidance on the interpretation of CPX results in the perioperative setting.

Randomized clinical trial of the effects of methylprednisolone on renal function after major vascular surgery

Perioperative renal dysfunction following abdominal aortic aneurysm (AAA) repair is multifactorial and may involve hypotension, hypoxia and ischaemia–reperfusion injury. Studies of cardiac and hepatic transplant surgery have demonstrated beneficial effects on renal function of high‐dose methylprednisolone administered before surgery.

National Institute of Academic Anaesthesia research priority setting exercise

BACKGROUND Formal research priority setting is a recognized way of identifying important clinical research questions and promoting these as topics for commissioned research. This paper describes a research priority setting exercise conducted by the National Institute of Academic Anaesthesia (NIAA). METHODS Possible research questions were identified from a questionnaire sent to holders of the Final Fellowship in Anaesthesia in Great Britain and Ireland and to lay representatives. The responses to the first questionnaire were collated to produce a list of potential research questions which were then sent to the same constituency for scoring. The results of this scoring process were considered by an expert panel and statements of research need generated for selected questions. The questions from the first round were also reviewed with the help of representatives of NIHR Evaluation, Trials and Studies Coordinating Centre (NETSCC). RESULTS For the first questionnaire, 308 responses with 447 suggestions for research were received. A total of 15 questions were included in the second questionnaire, for which 2226 responses were received. The expert panel identified five questions for prioritization. A further nine were identified from discussions with representatives of NETSCC. CONCLUSIONS A total of 14 research priorities were identified by the exercise, two of which have been submitted to the NIHR Health Technology Assessment (HTA) programme as statements of research need. Potential funding streams for the remaining questions are being sought. We discuss some implications of this exercise for research strategy in the speciality.