Stephen Kowalski

Thoracic epidural analgesia improves pulmonary function in patients undergoing cardiac surgery

Purpose: Pulmonary dysfunction commonly occurs following coronary artery bypass graft (CABG) surgery, increasing morbidity and mortality. We hypothesized that thoracic epidural anesthesia (TEA) would improve pulmonary function and would decrease complications in patients undergoing CABG surgery.Methods: This prospective, randomized, controlled trial was conducted with Ethics Board approval. Fifty patients, undergoing CABG surgery, were randomized to the epidural group or to the patient-controlled analgesia morphine group. Patients in the epidural group received a high, thoracic epidural, preoperatively. Intraoperatively, 0.75% ropivacaine was infused, followed postoperatively, by 0.2% ropivacaine for 48 hr. Outcome measurements included: visual analogue pain scores; spirometry; atelectasis scores on chest radiographs; and the incidence of atrial fibrillation.Results: Twenty-five patients were enrolled in each group. Patients in the epidural group had significantly less pain on the operative day, and for the subsequent two days. Compared to baseline, the forced expiratory volume in one second was significantly higher in the epidural group, on the first and second postoperative days (43.7±12.2%vs 36.4±12.0%,p<0.002, and 43.3±12.5%vs 38.4±11.0%,p<0.05). There was significantly more atelectasis in the control group, four hours postoperatively (p<0.04); however, on the third, postoperative day, the groups were similar with regards to this outcome. The incidence of atrial fibrillation was similar in both groups, and there were no complications related to the epidural.Conclusions: High TEA decreases postoperative pain and atelectasis and improves pulmonary function in patients undergoing CABG surgery. Our results support the use of TEA in this group of patients.RésuméObjectif: Des troubles pulmonaires surviennent fréquemment à la suite d’une chirurgie de pontage aortocoronarien (pAC), ce qui augmente la morbidité et la mortalité. Nous avons émis l’hypothèse que l’anesthésie péridurale thoracique (ApT) améliorerait la fonction pulmonaire et réduirait les complications chez les patients subissant une chirurgie de pAC.Méthode: Après avoir obtenu l’accord du Comité d’éthique, nous avons mené cette étude prospective, randomisée et contrôlée. Cinquante patients subissant une chirurgie pAC ont été randomisés dans deux groupes, péridurale ou analgésie contrôlée par le patient avec de la morphine. Les patients du groupe péridurale ont reçu une péridurale thoracique haute avant l’opération. pendant l’opération, ils ont reçu une perfusion de ropivacaïne 0,75 %, puis de la ropivacaïne 0,2 % pendant 48 h après l’opération. Les résultats mesurés étaient les scores de douleur sur l’échelle visuelle analogue, la spirométrie, les scores d’atélectasie sur les radiographies pulmonaires et l’incidence de fibrillation auriculaire.Résultats: Chaque groupe comprenait 25 patients. La douleur chez les patients du groupe péridurale était considérablement moins élevée le jour de l’opération et les deux jours suivants. par rapport aux données de base, le volume expiratoire maximal en une seconde était significativement plus élevé dans le groupe péridurale le premier et le deuxième jour postopératoire (43,7±12,2 % vs 36,4±12,0 %, p<0,002, et 43,3±12,5 % vs 38,4±11,0 %, p<0,05). L’atélectasie a été significativement plus élevée dans le groupe témoin quatre heures après l’opération (p<0,04) ; toutefois, le troisième jour postopératoire, les groupes ont montré des résultats d’atélectasie similaires. L’incidence de fibrillation auriculaire était semblable dans les deux groupes, et il n’y a pas eu de complication associée à la péridurale.Conclusion: L’analgésie péridurale thoracique haute réduit la douleur postopératoire et l’atélectasie et améliore la fonction pulmonaire chez les patients subissant un pAC. Nos résultats appuient l’utilisation de l’ApT chez ce groupe de patients.

Epinephrine decreases postoperative requirements for continuous thoracic epidural fentanyl infusions.

Epidural thoracic fentanyl infusions provide effective preoperative analgesia after thoracotomy; however, side effects can limit the effectiveness of this technique.This study evaluates epinephrine as an adjunct to continuous thoracic epidural fentanyl infusions after thoracotomy. Thirty-eight patients were studied in a prospective, randomized, double-blind trial comparing fentanyl alone to fentanyl with epinephrine 1:300,000. Epidural infusion rates were titrated to equivalent pain relief using a visual analog scale. With the addition of epinephrine, there was a significant reduction in fentanyl requirements (0.82 +/- 0.07 vs 1.19 +/- 0.11 micro gram centered dot kg-1 centered dot h-1, P = 0.005, repeated-measures analysis of variance) and in plasma fentanyl concentrations (steady state: 0.91 +/- 0.13 vs 1.65 +/- 0.23 ng/mL, P = 0.007, repeated-measures analysis of variance). There were no differences in pain scores, side effects, spirometry, patient satisfaction scores, or hemodynamic variables. This study demonstrates that adding epinephrine 1:300,000 to continuous thoracic epidural infusions decreases fentanyl requirements titrated for effective analgesia. The reduction in fentanyl requirements was associated with reduced fentanyl plasma concentrations. (Anesth Analg 1996;82:760-5)

Effects of interpleural bupivacaine (0.5%) on canine diaphragmatic function.

Several authors have questioned the potential for phrenic nerve paralysis with interpleural analgesia. This study was designed to examine the potential for phrenic nerve paralysis with the use of interpleural bupivacaine in dogs. Seven dogs were anesthetized, tracheally intubated, and allowed to breathe spontaneously with halothane/oxygen while in the supine position. After a midline laparotomy, two wires were inserted into the costal portion of each hemidiaphragm for measurement of electromyographic (EMG) signals. A balloon catheter was placed in the abdominal cavity to measure abdominal pressure. The abdomen was then closed. Airway pressure was measured through a side port in the endotracheal tube. Bilateral interpleural catheters were inserted with the loss-of-resistance technique. Each dog was used for two experiments, one on each side, except for one animal. To assess the contribution of the ipsilateral diaphragm to total respiratory effort, the airway was occluded at functional residual capacity for three consecutive breaths, and EMG, airway pressure, and abdominal pressure were measured. In five of nine experiments with bupivacaine, there was complete loss of EMG activity on the side of the injection. In two dogs, there was partial loss of diaphragmatic function, and in the remaining two, there was no change in EMG. In the normal saline solution group (n = 4), there was no change in the EMG. Two dogs that received bilateral bupivacaine injections developed paradoxical respiration with negative inspiratory intraabdominal pressures. Phrenic nerve paralysis or paresis can occur with interpleural blockade. The factors affecting the occurrence of this complication remain to be elucidated.

The Perioperative Anticoagulant Use for Surgery Evaluation (PAUSE) Study for Patients on a Direct Oral Anticoagulant Who Need an Elective Surgery or Procedure: Design and Rationale

Background The perioperative management of patients who take a direct oral anticoagulant (DOAC) for atrial fibrillation and require treatment interruption for an elective surgery/procedure is a common clinical scenario for which best practices are uncertain. The Perioperative Anticoagulant Use for Surgery Evaluation (PAUSE) study is designed to address this unmet clinical need. We discuss the rationale for the PAUSE design and analysis plan as well as the rationale supporting the perioperative DOAC protocol. Methods PAUSE is a prospective study with three parallel cohorts, one for each DOAC, to assess a standardized but patient-specific perioperative management protocol for DOAC-treated patients with atrial fibrillation. The perioperative protocol accounts for DOAC type, patients renal function and surgery/procedure-related bleeding risk. The primary study aim is to demonstrate the safety of the PAUSE protocol for the perioperative management of each DOAC. The secondary aim is to determine the effect of the pre-procedure interruption on residual anticoagulation when measured by the dilute thrombin time for dabigatran and anti-factor Xa levels for rivaroxaban and apixaban. The study hypothesis is that the perioperative management protocol for each DOAC is safe for patient care, defined by expected risks for major bleeding of 1% (80% power to exclude 2%), and for arterial thromboembolism of 0.5% (80% power to exclude 1.5%) in each DOAC group. Conclusion The PAUSE study has the potential to establish a standard-of-care approach for the perioperative management of DOAC-treated patients. The PAUSE management protocol is designed to be easily applied in clinical practice, as it is standardized and also patient specific.

Pre-hospital and initial management of head injury patients: An update.

Background: Most of the bad outcomes in patients with severe traumatic brain injury (TBI) are related to the presence of a high incidence of pre-hospital secondary brain insults. Therefore, knowledge of these variables and timely management of the disease at the pre-hospital period can significantly improve the outcome and decrease the mortality. The Brain Trauma Foundation guideline on “Prehospital Management” published in 2008 could provide the standardized protocols for the management of patients with TBI; however, this guideline has included the relevant papers up to 2006. Methods: A PubMed search for relevant clinical trials and reviews (from 1 January 2007 to 31 March 2013), which specifically discussed about the topic, was conducted. Results: Based on the evidence, majority of the management strategies comprise of rapid correction of hypoxemia and hypotension, the two most important predictors for mortality. However, there is still a need to define the goals for the management of hypotension and inclusion of newer difficult airway carts as well as proper monitoring devices for ensuring better intubation and ventilatory management. Isotonic saline should be used as the first choice for fluid resuscitation. The pre-hospital hypothermia has more adverse effects; therefore, this should be avoided. Conclusion: Most of the management trials published after 2007 have focused mainly on the treatment as well as the prevention strategies for secondary brain injury. The results of these trials would be certainly adopted by new standardized guidelines and therefore may have a substantial impact on the pre-hospital management in patients with TBI.

High Spinal Anesthesia Enhances Anti-Inflammatory Responses in Patients Undergoing Coronary Artery Bypass Graft Surgery and Aortic Valve Replacement: Randomized Pilot Study

Background Cardiac surgery induces many physiologic changes including major inflammatory and sympathetic nervous system responses. Here, we conducted a single-centre pilot study to generate hypotheses on the potential immune impact of adding high spinal anaesthesia to general anaesthesia during cardiac surgery in adults. We hypothesized that this strategy, previously shown to blunt the sympathetic response and improve pain management, could reduce the undesirable systemic inflammatory responses caused by cardiac surgery. Methods This prospective randomized unblinded pilot study was conducted on 14 patients undergoing cardiac surgery for coronary artery bypass grafting and/or aortic valve replacement secondary to severe aortic stenosis. The primary outcome measures examined longitudinally were serum pro-inflammatory (IL-6, IL-1b, CCL2), anti-inflammatory (IL-10, TNF-RII, IL-1Ra), acute phase protein (CRP, PTX3) and cardiovascular risk (sST2) biomarkers. Results The kinetics of pro- and anti-inflammatory biomarker was determined following surgery. All pro-inflammatory and acute phase reactant biomarker responses induced by surgical stress were indistinguishable in intensity and duration between control groups and those who also received high spinal anaesthesia. Conversely, IL-10 levels were markedly elevated in both intensity and duration in the group receiving high spinal anesthesia (p = 0.005). Conclusions This hypothesis generating pilot study suggests that high spinal anesthesia can alter the net inflammatory response that results from cardiac surgery. In appropriately selected populations, this may add incremental benefit by dampening the net systemic inflammatory response during the week following surgery. Larger population studies, powered to assess immune, physiologic and clinical outcomes in both acute and longer term settings, will be required to better assess potential benefits of incorporating high spinal anesthesia. Trial Registration ClinicalTrials.gov NCT00348920

General intensive care for patients with traumatic brain injury: An update

Background: Traumatic brain injury (TBI) is a growing epidemic throughout the world and may present as major global burden in 2020. Some intensive care units throughout the world still have no access to specialized monitoring methods, equipments and other technologies related to intensive care management of these patients; therefore, this review is meant for providing generalized supportive measurement to this subgroup of patients so that evidence based management could minimize or prevent the secondary brain injury. Methods: Therefore, we have included the PubMed search for the relevant clinical trials and reviews (from 1 January 2007 to 31 March 2013), which specifically discussed about the topic. Results: General supportive measures are equally important to prevent and minimize the effects of secondary brain injury and therefore, have a substantial impact on the outcome in patients with TBI. The important considerations for general supportive intensive care unit care remain the prompt reorganization and treatment of hypoxemia, hypotension and hypercarbia. Evidences are found to be either against or weak regarding the use of routine hyperventilation therapy, tight control blood sugar regime, use of colloids and late as well as parenteral nutrition therapy in patients with severe TBI. Conclusion: There is also a need to develop some evidence based protocols for the health-care sectors, in which there is still lack of specific management related to monitoring methods, equipments and other technical resources. Optimization of physiological parameters, understanding of basic neurocritical care knowledge as well as incorporation of newer guidelines would certainly improve the outcome of the TBI patients.

Specific intensive care management of patients with traumatic brain injury: Present and future

Traumatic brain injury (TBI) is a major global problem and affects approximately 10 million peoples annually; therefore has a substantial impact on the health-care system throughout the world. In this article, we have summarized various aspects of specific intensive care management in patients with TBI including the emerging evidence mainly after the Brain Trauma Foundation (BTF) 2007 and also highlighted the scope of the future therapies. This review has involved the relevant clinical trials and reviews (from 1 January 2007 to 31 March 2013), which specifically discussed about the topic. Though, BTF guideline based management strategies could provide standardized protocols for the management of patients with TBI and have some promising effects on mortality and morbidity; there is still need of inclusion of many suggestions based on various published after 2007. The main focus of majority of these trials remained to prevent or to treat the secondary brain injury. The future therapy will be directed to treat injured neurons and may benefit the outcome. There is also urgent need to develop some good prognostic indicators as well.

Weaning from mechanical ventilation using tracheostomy cuff deflation and a one-way speaking valve: a historical-cohort series

To the Editor, Overall, 5–15% of ventilated patients require prolonged mechanical ventilation, most frequently with a tracheostomy. The optimal method for weaning patients has not been established. Prior research indicates that gradually increasing spontaneous breathing results in faster liberation. Unfortunately, gradual liberation can take weeks to months, and the use of tracheostomy renders the patient unable to speak. With a speaking valve trial (SVT), however, the tracheostomy cuff is deflated and a one-way valve is attached. Hence, on expiration, air exits the lungs through the vocal cords, enabling vocalization. We report a historical case series on tracheostomized patients undergoing SVT. The sample consisted of 34 patients admitted to the intermediate intensive care unit during 2013-2014. We conducted a chart review following approval of the University of Manitoba Health Research Board (January, 2017) to identify those with an SVT. Patient profiles were extracted, and data are reported as means (standard deviation). Seventeen patients underwent an SVT (Table). Two patients failed the SVT: Patient 1 had repeated aspiration pneumonia, and attempts at cuff deflation were eventually stopped. Patient 2 had poor bulbar function with no control of oral secretions, precluding cuff deflation, which was obvious immediately. The remaining 15 patients’ male/ female ratio was 9/6, with a mean (standard deviation [SD]) age of 53 (17) yr All patients had respiratory muscle weakness with a mean (SD) vital capacity of 893 (461) mL and a maximum inspiratory force of -20 (11) cm H2O during the initial SVT. SVT patients were ventilated for 94 (44) days and could speak after 71 (39) days of ventilation. Thus, on average, these patients could speak and clearly communicate for 24% of their time on a ventilator. Patients 3 and 17 were liberated completely from mechanical ventilation within days of initiating the SVT. The mean (SD) duration of the initial SVT was 238 (238) min [range, five minutes to 12 hr]. This case series reports the successful use of SVTs in a diverse group of patients who required prolonged mechanical ventilation. There was no protocolized use of the SVTs. The SVTs were initiated based on the attending physician’s judgement, as some patients were closer to being liberated than others. The main contraindication was the risk of aspiration. The major observation among patients with speaking valves was the psychological benefit. Many patients had been unable to speak for months, which can be a great psychological burden to the patients and their families. The paucity of research in this context is surprising given that 90% of patients who remember their intensive care unit experience indicate being ‘‘moderately’’ to ‘‘extremely’’ bothered by the inability to speak. Tracheostomized patients report symptoms including frustration, fear of safety, sadness, anxiety, and powerlessness related to loss S. Kowalski, MD, FRCPC (&) L. Girling, BScHons Department of Anesthesia & Perioperative Medicine, Section of Critical Care, University of Manitoba, Winnipeg, MB, Canada e-mail: sekowalski@hsc.mb.ca

Assessment of cough strength in patients with a tracheostomy

To the Editor, A patient’s weak cough has been identified as a risk factor for re-intubation. It may also impair weaning in patients with a tracheostomy. The study described herein assessed whether cough strength is enhanced along with tracheal cuff deflation with a one-way valve. This randomized crossover study of mechanically ventilated, tracheostomized patients in the intermediate intensive care unit was registered with Clinical Trials.gov (NCT02566512). The University of Manitoba Health Research Board approved the study (May, 2016), and all patients provided informed written consent. The study was conducted between September 2015 and January 2017. A convenience sample of 20 patients was chosen. The peak expiratory flow rate (PEFR) while coughing was measured by a respiratory therapist using an air zone peak expiratory flow meter. With the tracheostomy cuff inflated, the PEFR meter was attached to the tracheostomy tube. The patient was instructed to take as deep a breath as possible and then cough. With the tracheostomy cuff deflated, a one-way valve (Shiley speaking valve) was attached to the tracheostomy tube. The patient used a mouthpiece that was connected to the PEFR meter. Nose clips were applied. The patient was again instructed to take as deep a breath as possible and then cough. All measurements were performed four times and averaged. Patients were randomized to begin with either the tracheal cuff inflated as the first intervention (group 1) or with the tracheal cuff deflated as the first intervention (group 2). Data, reported as mean (standard deviation), were compared using a paired Student’s t test. A value of P\ 0.05 was considered statistical significant. Twenty patients were enrolled in the study. Their mean (standard deviation [SD]) age was 64 (13) yr, and they had been on mechanical ventilation for 64 (20) days. Their mean (SD) baseline vital capacity was 1,061 (337) mL and maximum inspiratory pressure was -29.5 (9.4) cm H2O. Among the 20 patients, 19 had a greater PEFR when coughing with the tracheostomy cuff deflated (Figure). The mean (SD) PEFR with the cuff deflated and a one-way valve was 38% greater than when coughing through the tracheostomy tube [161 (58) vs 100 (48) L min]. The randomization order had no effect on outcome. The patient whose flow rate was lower with the cuff deflated was subsequently found to have subglottic stenosis. Among patients who require mechanical ventilation, 515% exhibit a prolonged time for liberation from mechanical ventilation, and most ultimately require tracheostomy. Hernandez et al. showed that patients were liberated more quickly when the tracheal cuff was deflated during spontaneous breathing trials, and they had a lower incidence of pulmonary infections. Trial registration: www.clinicaltrials.gov, NCT 02566512. Registered June 23, 2015.