Cardiac Stress in High-Risk Patients Undergoing Major Endovascular Surgery-Focus on Diastolic Function.

OBJECTIVES: The purpose of this study was to determine the relationship between the changes in diastolic function and their association with cardiac biomarkers in the perioperative period in patients undergoing complex endovascular aortic repair. DESIGN: Prospective observational study. SETTING: Single-center academic hospital, central teaching hospital in Warsaw, Poland. PARTICIPANTS: The study comprised 27 high-risk patients scheduled for elective endovascular repair of aortic aneurysm. INTERVENTIONS: Complex endovascular procedure using branched endograft of the thoracoabdominal aorta. Branches of the stent grafts included renal arteries, the superior mesenteric artery, and the celiac trunk. MEASUREMENTS AND MAIN RESULTS: The primary outcome was to evaluate changes in diastolic function parameters assessed with transthoracic echocardiography at two and 24 hours postoperatively. The major secondary outcomes were changes in N-terminal pro-B-type natriuretic peptide (NT-proBNP) and troponin I concentrations, systolic function parameters, hemodynamic parameters at two and 24 hours, length of hospital stay, and 30-day mortality. There was a reduction in e' wave velocity on both the septal and lateral sides at two hours compared with the baseline (p = 0.041 and p = 0.05, respectively). There was an increase in both NT-proBNP and troponin I concentrations after surgery (p = 0.002 and p = 0.034, respectively), with troponin I peaking two hours after surgery and NT-proBNP peaking 24 hours after surgery. CONCLUSIONS: Patients undergoing a branched endovascular aortic repair of a thoracoabdominal aortic aneurysm experience a cardiac insult that manifests with deterioration in diastolic parameters and concomitant increases of troponin and NT-proBNP concentrations. Additional large-scale prospective studies are required to confirm this phenomenon.

Quantification of piritramide in human colostrum.

WHAT IS KNOWN AND OBJECTIVE: In our university hospital (UZBrussel), one of the options to control post-operative pain after a Caesarean section under general anaesthesia is to administer piritramide by patient-controlled intravenous analgesia (PCIA). As no information is available about the possible transfer of this synthetic narcotic analgesic into breastmilk, women are frequently advised not to breastfeed their newborn. A sensitive liquid chromatographic (LC) method coupled with UV detection will therefore be developed and validated for the quantification of piritramide in colostrum samples to evaluate the presence of the analgesic in the first milk. METHODS: The method included the isolation and concentration of piritramide from colostrum using protein precipitation and solid-phase extraction (SPE) using a mixed-mode cation exchange sorbent. Subsequently, the extracted samples were analysed on a microbore C18 column (1 mm id) and a mobile phase consisting of 15 mm ammonium hydroxide in methanol/tetrahydrofuran/water 50 : 10 : 40 V/V/V. RESULTS AND DISCUSSION: As colostrum contains a high amount of proteins, mixed-mode cation exchange SPE was preceded by a 1 : 2 dilution and protein precipitation with phosphoric acid followed by double centrifugation of the samples. The reversed-phase LC-UV method used a mobile phase at alkaline pH to obtain a selective method for piritramide and the internal standard pipamperone. After investigating the validation characteristics (linearity, accuracy, precision and stability), samples from ten patients who had received piritramide via PCIA during the first 48 h post-partum were analysed. WHAT IS NEW AND CONCLUSION: To the best of our knowledge, this is the first method described for the quantification of the synthetic narcotic analgesic piritramide in colostrum samples. The obtained results suggest that after the administration of this opioid by PCIA to nursing mothers low concentrations of piritramide can be found in the first milk, but are mostly below the limit of quantification of 30 ng/mL.

Randomised controlled trial of spinal anaesthesia with bupivacaine or 2-chloroprocaine during caesarean section.

BACKGROUND: Neuraxial anaesthesia is the desired method for Caesarean section. Bupivacaine is a well-known local anaesthetic. It has a long duration of action and can cause unpredictable levels of anaesthesia with subsequent prolonged discharge time. 2-Chloroprocaine has a rapid onset of action, producing an excellent sensory and motor block and has a rapid hydrolysis in the bloodstream by pseudocholinesterase. We compared bupivacaine and 2-chloroprocaine for spinal anaesthesia during Caesarean section. The primary endpoint was the earliest reversal sign of the motor block. METHODS: Sixty ASAI/II patients, planned for elective singleton Caesarean section, were equally randomised to three groups. All patients received a combined spinal-epidural anaesthesia. The first group received 2-chloroprocaine (40 mg) without sufentanil, the second group received 2-chloroprocaine (40 mg) with sufentanil (1 µg) and the third group received hyperbaric bupivacaine (7.5 mg) with sufentanil (1 µg) as a spinal anaesthetic. Motor and sensory blockade were assessed at specific time points. RESULTS: There was no difference between the three groups regarding the time to regression of the motor block. However, at 5 min post spinal injection, the level of sensory block was higher for both groups with 2-chloroprocaine, in comparison with the bupivacaine group. CONCLUSION: 2-Chloroprocaine can be used for low risk Caesarean section in healthy parturients. There is no difference in time to motor block resolution compared to bupivacaine. Motor recovery seems more predictable for 2-chloroprocaine and may be beneficial for the breastfeeding initiation.

Usability of dexmedetomidine for deep sedation in infants and small children with respiratory morbidities.

BACKGROUND: Children with respiratory morbidities are at increased risk of developing adverse respiratory events while undergoing deep sedation. Dexmedetomidine possesses sedative properties with minimal respiratory depression. This report aimed to determine the usability of dexmedetomidine in children with significant respiratory morbidities who require deep sedation. METHODS: Medical records of children with ASA classification III who had at least three characteristics of respiratory morbidities and who received dexmedetomidine sedation for magnetic resonance imaging (MRI) between January 2014 and May 2015 were retrospectively reviewed. Dexmedetomidine was administered as a bolus of 1 µg/kg over 10 min followed by 1 µg/kg/h infusion. If necessary, an additional bolus dose was given and the infusion rate was increased to 2 µg/kg/h. Respiratory morbidities, haemodynamic parameters, total dexmedetomidine dose, adverse cardiorespiratory events and sedation characteristics were analysed. RESULTS: Nineteen out of 642 children who underwent MRI were eligible for evaluation. Seventeen children (89%) had at least four characteristics of respiratory morbidities. The median [IQR] age was 9 months [3.5-14]. All patients completed MRI scans while breathing spontaneously via the native airway. No episodes of adverse respiratory events or haemodynamic instability were observed. Children who were administered a lower dexmedetomidine dose and had a shorter sedation time were more likely to be younger than 1 year of age. CONCLUSION: These data demonstrate that dexmedetomidine deep sedation was well-tolerated in children with significant respiratory morbidities. Moreover, children younger than 1 year of age were administered lower dexmedetomidine dose than children older than 1 year of age for the same sedation level. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT02555605.

Fighting human error : what surgeons can learn from aviators.

BACKGROUND: The rigorous implementation of safety policies have made air travel one of the safest modes of transport. Health institutions and hospital managing bodies increasingly adopt cues from aviation safety protocols and policies in an attempt to reduce medical errors and patient harm. Among hospital staff, surgeons are most likely to be confronted with these aviation-derived safety concepts. METHODS: This article aims to familiarize surgeons with the concepts and methodology of safety policies in modern aviation safety, many of which have been applied in the setting of surgery, or have potential to do so. We review the use of checklists, crew resource management, the sterile cockpit, blame free reporting and human fatigue. We discuss how these concepts can be translated to the operating room and illustrate their relevance through a comparative description of historical air accidents and surgical incidents from our own clinical experience. We also indicate relevant differences and similarities between flight crews and surgical teams and their respective infrastructures, as these may impede or facilitate the adoption of aviation safety policies. Finally, we offer some recommendations to effectively implement aviation safety policies in the operating room.

Effect of a single small volume fluid bolus with balanced or un-balanced fluids on chloride and acid-base status: a prospective randomized pilot study (the FLURES-trial).

OBJECTIVE: To compare the short-term effects on acid base, electrolyte status and urine output of a single fluid bolus of saline to that of the balanced solution Plasmalyte® in critically ill patients. METHODS: Prospective, randomized, controlled trial. Adult patients (≥ 18 years) admitted to the ICU receiving a fluid bolus were randomized to receive 1 L of saline (NaCl 0.9%, Baxter) or a balanced fluid [Plasmalyte® (Baxter)]. Blood samples and urine output were collected just before (T0), just after (T1), 2 h after (T2) (only for urinary output) and three hours after termination of the fluid bolus (T4). The effect of fluid boluses on serum chloride, apparent strong ion difference, base excess, urinary output and blood pressure or vasopressor need were analyzed. MAIN RESULTS: Patients who received a 1 L saline fluid bolus had a significant increase in serum chloride (1.60; 95% CI 1.10 to 2.10; P < 0.001) and short-term decrease in apparent strong ion difference (- 1.85; 95% CI - 2.71 to - 0.99; P < 0.001) and base excess (- 0.90; 95% CI - 1.31 to - 0.50; P < 0.001). We observed a 17% increase in patients developing hyperchloremia in the saline group (0.17; 95% CI 0.05 to 0.29; P = 0.005). No significant difference in urinary output, blood pressure or vasopressor need was observed in either group. CONCLUSION: Even a single, small bolus of saline, administered to critically ill patients, causes a significant increase in chloride concentration and a decrease in apparent strong ion difference and base excess, and an increase in the number of patients developing hyperchloremia. No difference in effect on urinary output, blood pressure or vasopressor need was observed between the two groups. EUDRACT NUMBER: 2014-001005-41; date of registration: 28/10/2014. LOCAL EC APPROVAL: EC project number 2014/038.

Assessment of intraoperative microaspiration: does a modified cuff shape improve sealing?

BACKGROUND: Intra-operative aspiration of oropharyngeal secretions is associated with post-operative pneumonia. The use of endotracheal tubes (ETTs) with a modified cuff shape could be one preventive action. In this clinical, prospective, randomised controlled trial, we hypothesised that altering the cuff shape to a tapered shape could reduce the aspiration incidence. The primary outcome was aspiration of dye solution into the trachea. METHODS: Patients scheduled for lumbar surgery were intubated with either an ETT with a barrel-shaped polyvinylchloride cuff (control group, n = 30) or tapered-shaped polyvinylchloride cuff (intervention group, n = 30). Subsequently, instillation with methylthioninium chloride was performed. At 10, 30, 60, 90, and 120 min after intubation, bronchoscopy was performed assessing the degree of dye descent along the cuff and digitally stored. Single blind review of the videoclips provided data on incidence of dye aspiration and depth of penetration along the cuff. RESULTS: The traditional cuff showed descent of dye into the trachea in 20% of the patients. Although a tapered-shaped polyvinylchloride cuff leaked up to the second third of the cuff, no dye leakage into the trachea was observed. The use of a tapered-shaped cuff had a protective role against aspiration (T30: OR 3.0, CI 1.57-5.75; P = 0.001). CONCLUSIONS: Short-term use of tapered-shaped polyvinylchloride cuffs in surgical patients results in more effective sealing of the tracheal lumen in comparison with a traditional barrel-shaped polyvinylchloride cuffs. Further evaluation is needed to determine whether a reduction in post-operative pneumonia can be demonstrated when these cuffs are used.

Spinal cord stimulation modulates cerebral function: an fMRI study.

INTRODUCTION: Although spinal cord stimulation (SCS) is widely used for chronic neuropathic pain after failed spinal surgery, little is known about the underlying physiological mechanisms. This study aims to investigate the neural substrate underlying short-term (30 s) SCS by means of functional magnetic resonance imaging in 20 patients with failed back surgery syndrome (FBSS). METHODS: Twenty patients with FBSS, treated with externalized SCS, participated in a blocked functional magnetic resonance imaging design with stimulation and rest phases of 30 s each, repeated eight times in a row. During scanning, patients rated pain intensity over time using an 11-point numerical rating scale with verbal anchors (0 = no pain at all to 10 = worst pain imaginable) by pushing buttons (left hand, lesser pain; right hand, more pain). This scale was back projected to the patients on a flat screen allowing them to manually direct the pain indicator. To increase the signal-to-noise ratio, the 8-min block measurements were repeated three times. RESULTS: Marked deactivation of the bilateral medial thalamus and its connections to the rostral and caudal cingulate cortex and the insula was found; the study also showed immediate pain relief obtained by short-term SCS correlated negatively with activity in the inferior olivary nucleus, the cerebellum, and the rostral anterior cingulate cortex. CONCLUSIONS: Results indicate the key role of the medial thalamus as a mediator and the involvement of a corticocerebellar network implicating the modulation and regulation of averse and negative affect related to pain. The observation of a deactivation of the ipsilateral antero-medial thalamus might be used as a region of interest for further response SCS studies.

Comparison of the effects of intrathecal administration of levobupivacaine and lidocaine on the prostaglandin E2 and glutamate increases in cerebrospinal fluid: a microdialysis study in freely moving rats.

BACKGROUND: Bupivacaine has a lower incidence of transient neurological symptoms than lidocaine after intrathecal (i.t.) injection. The increased toxic potential of lidocaine does not support its use in the clinical setting and could be related to augmented levels of spinal prostaglandin E(2) (PGE(2)). We tested whether levobupivacaine leads to lower PGE(2) levels than lidocaine. Moreover, we compared the release of PGE(2) and glutamate after i.t. injections of levobupivacaine or lidocaine. METHODS: Rats were anaesthetized for implantation of an i.t. dialysis catheter. This allowed sampling dialysates of cerebrospinal fluid (CSF) for measuring PGE(2) and glutamate levels. The microdialysis setting included baseline sampling and was followed by an i.t. injection of levobupivacaine 250 microg, 100 microg, or saline. PGE(2) and glutamate levels in CSF were analysed for 4 h. In addition, the residual effect of a second i.t. injection on, respectively, of PGE(2) and glutamate changes was compared after injection of either 250 or 100 microg levobupivacaine, 1000 or 400 microg lidocaine, or saline. RESULTS: Prolonged spinal PGE(2) increases lasting 50-120 min were observed after levobupivacaine injection. Higher PGE(2) concentrations were observed after the second lidocaine 1000 microg injection. Glutamate release after the second injection did not vary between the local anaesthetic groups. CONCLUSIONS: Spinal PGE(2) levels are similarly increased after i.t. levobupivacaine injection of 250 and 100 microg. A higher PGE(2) response was observed after a second i.t. injection in the animals receiving 1000 microg lidocaine than those receiving 400 mg lidocaine or either dose of levobupivacaine.

Doppler echocardiography as a modern tool to diagnose and monitor non-cardiac surgical patients: does it improve outcome?

Echocardiography and Doppler provide intraoperative and immediate insight when a haemodynamic deterioration occurs. Both morphological and haemodynamic features can be diagnosed instantly. Furthermore, this tool is used as a functional haemodynamic monitoring device offering on line information on systolic function, preload and afterload. No clear data exist on improvement of outcome in noncardiac surgery, but analogy to cardiac patients suggest strongly outcome can be advanced with echo-Doppler.

Evaluation of the hemodynamic and respiratory effects of inverse ratio ventilation with a right ventricular ejection fraction catheter.

Pc-IRV has been shown to have respiratory advantages, compared with CPPV. However, the hemodynamic effects of this ventilation mode have not yet been fully elucidated. We used a REF catheter to monitor the hemodynamic changes in the RV. Fifteen ARDS patients were included in the study. The respiratory data showed a 35 percent decrease of PIP and a 32 percent decrease of VTi and VTe with Pc-IRV 4:1 compared with CPPV. Hemodynamic parameters showed a significant incrase in CI (17 percent) in Pc-IRV 4:1, without change in REF. Observing in retrospect the pressure-volume relationship of the RV, we could differentiate a preload (group 1) and an afterload dependent group of patients (group 2), CI was significantly different in the two groups as it rose only in the preload-dependent patients. RVEDVI showed a significant change in group 1, whereas this was absent in the second group. REF was maintained in switching ventilation from CPPV to Pc-IRV with increasing I:E ratio. Pc-IRV appears to be a good alternative ventilatory mode in comparison with CPPV in a selected group of patients with preload dependency (responders); in these patients with respiratory insufficiency, close hemodynamic monitoring is required to optimize ventilation, especially in relation to the hemodynamic effects.

Acute hemodynamic changes of pressure-controlled inverse ratio ventilation in the adult respiratory distress syndrome. A transesophageal echocardiographic and Doppler study.

Twelve patients with the adult respiratory distress syndrome were included in this study and evaluated by transesophageal echocardiography and Doppler, assessing right and left ventricular intracardiac blood flow alterations with progressive increase of inspiration-to-expiration (I-E) ratios. Whereas midpulmonary artery flow parameters did not show any change, early left ventricular filling demonstrated a significant increase after switching the ventilatory mode from volume to pressure-controlled ventilation with 2:1 I-E ratio (end-inspiration: 39 +/- 26 cm with positive end-expiratory pressure [PEEP]-ventilation to 68 +/- 56 cm with pressure-controlled inverse-ratio ventilation, 2:1; p < 0.01; at end-expiration, from 67 +/- 21 cm with PEEP-ventilation to 83 +/- 36 cm with pressure-controlled ventilation 1:1; p < or = 0.05), resulting probably from different ventilatory flow and pressure curves. In the meanwhile, cardiac index demonstrated a significant augmentation (from 4.73 +/- 1.71 L/min.m2 to 5.56 +/- 1.66 L/min.m2; p < 0.05). Pressure-controlled inverse ratio ventilation results in both respiratory and hemodynamic advantages as is demonstrated by this study.

Evaluation of transesophageal echocardiography as a diagnostic and therapeutic aid in a critical care setting.

OBJECTIVES: To assess the impact of transesophageal echocardiography (TEE) on therapeutic management in relation to pulmonary artery catheterization (PAC) in the ICU. DESIGN: Retrospective analysis of 108 consecutive TEE video and related patient files during a 7-month period. SETTING: A 33-bed medical and surgical ICU. METHODS: All critically ill patients with or without PAC in whom a TEE was performed, excluding postoperative cardiac surgical patients. Patients were divided in a cardiac and a septic group depending on the primary disease on admission to the ICU. The impact of TEE in relation to PAC on ICU management was evaluated in whether therapy changes were performed strictly on the basis of the TEE findings. MAIN RESULTS: Of 64% of patients with a PAC, 44% underwent therapy changes after TEE: 41% in the cardiac and 54% in the septic subgroup. In 41% of patients without a PAC, TEE led to a change in therapy. CONCLUSIONS: TEE results in altered therapeutic management in at least one third of our (noncardiac surgery) ICU patient population independent of the presence of a PAC.

Left ventricular systolic and diastolic function in septic shock.

OBJECTIVE: The identification of myocardial dysfunction in septic shock has not yet been fully elucidated. We therefore studied patients with persistently vasopressor-dependent septic shock, both with invasive haemodynamic monitoring and transoesophageal two-dimensional and Doppler echocardiography (TEE). DESIGN: Prospective study. SETTING: General ICU in University Hospital. PATIENTS AND METHODS: All patients were monitored with arterial and pulmonary artery catheters. Haemodynamics were obtained concomitantly with TEE measurements. TEE was performed at three levels: a) a midpapillary short axis view of the left ventricle (LV) in order to measure end-systolic and end-diastolic areas; b) at the level of both the mitral valve for early (E) and late (A) filling parameters and c) the level of the right upper pulmonary vein for systolic (S) and diastolic (D) filling characteristics. Each parameter was characterised by maximal flow velocity and time velocity integral. RESULTS: Although the measurements of cardiac index demonstrated a wide range, three subsets of patients were identified post hoc after analysis on the basis of different Doppler patterns: first, patients with a LV without regional wall motion abnormalities and both E/A and S/D greater than 1 (group 1); second, patients with a comparable haemodynamic condition, apparently normal LV systolic function but with altered Doppler patterns: S/D less than 1 in conjunction with E/A more than 1 (group 2); finally, patients with compromised global LV systolic function, E/A less than 1 and S/D less than (group 3). CONCLUSIONS: Notwithstanding the known various interfering factors which limit the broad applicability of TEE to determine LV function in septic shock, our data suggest that cardiac dysfunction in septic shock shows a continuum from isolated diastolic dysfunction to both diastolic and systolic ventricular failure. These data strengthen the need of including the evaluation of pulmonary venous Doppler parameters in each investigation in order to obtain supplementary information to interpret diastolic function of the LV in septic shock patients.

Outcome in critically ill patients with candidal fungaemia: Candida albicans vs. Candida glabrata.

In a retrospective study (1 January 1992-12 December 1998), we investigated population characteristics and outcome in critically ill patients with fungaemia involving C. albicans (n=41) and C. glabrata (n=15). Patients with C. glabrata fungaemia were significantly older compared with patients in the C. albicans group (P=0.024). There were no other differences in population characteristics or severity of illness. Logistic regression analysis showed age (P=0.021), the presence of a polymicrobial blood stream infection (P=0.039), and renal failure (P=0.044) to be independent predictors of mortality. There was no significant difference in in-hospital mortality between the C. glabrata and C. albicans groups (60.0% vs. 41.5%; P=0.24). Since age was an independent predictor of mortality, the trend towards a higher mortality in patients with C. glabrata can be explained by this population being significantly older. In conclusion, we found no difference in mortality between patients with fungaemia involving C. albicans and C. glabrata.

Phosphorylcholine coating of extracorporeal circuits provides natural protection against blood activation by the material surface.

OBJECTIVE: The aim of this study is to evaluate the use of a new coating, mimicking the outer cell membrane, in paediatric cardiac surgery. METHODS: Two groups of ten patients with a body weight below 8 kg, undergoing elective cardiac operations for different congenital anomalies, were prospectively enrolled in this study. In one group the whole extracorporeal circuit, including the cannulas, was coated with phosphorylcholine (PC). In the second group the same circuit was used without coating. Platelet activation (thromboxane B2 (TXB2), beta-thromboglobulin (betaTG)), activation of the coagulation system (F1+2), leukocyte activation (CD11b/CD18) and terminal complement activation (TCC) were analyzed pre-cardiopulmonary bypass (CPB), at 15, 60 min of CPB, at the end of CPB, 20 min post CPB and at postoperative day 1 and 6. RESULTS: No statistical differences were found for F1+2 and CD11b/CD18. After onset of CPB mean levels of TCC remained stable in the PC group whereas an increase was observed in the control group. During CPB betaTG values in both groups increased to a maximum at the end of CPB. Within groups the increase in betaTG levels during CPB was statistically significant (P<0.05) from baseline in the control group starting from 60 min of CPB whereas no statistical difference was observed in the PC group. After the start of CPB TXB2 mean levels increased to 405+/-249 pg/ml in the PC group vs. 535+/-224 pg/ml in the control group. After this initial increase there was a small decline in the PC group with further increase. This was in contrast to the control group were TXB2 levels further increased up to a mean of 718+/-333 pg/ml at the end of CPB (P=0.016). CONCLUSIONS: Phosphorylcholine coating had a favourable effect on blood platelets, which is most obvious after studying the changes during cardiopulmonary bypass. A steady increase of TXB2 and betaTG was observed in the control group, whereas plateau formation was observed in the phosphorylcholine group. Clinically, this effect may contribute to reduced blood loss and less thromboembolic complications. Complement activation is lower in the coated group.

Post-traumatic transverse dissection of the caudal thoracic aorta diagnosed by transoesophageal echocardiography.

Transverse dissection of the distal aorta is a rather rare complication of spinal trauma. Transoesophageal echocardiography (TEE) appears to have a supplementary value in diagnosing post-traumatic transverse dissection of the caudal thoracic aorta. We present a case where the advantages and additional value of TEE are particularly apparent.

A combination of buprenorphine and naloxone compared with buprenorphine administered intramuscularly in postoperative patients.

Sixty patients suffering from moderate to severe pain following either orthopaedic or gynaecological surgery were treated with intramuscular buprenorphine (0.3 mg) or an intramuscular combination of buprenorphine (0.3 mg)/naloxone (0.2 mg) and the analgesic efficacy and safety of the two treatments was compared. The evaluation of efficacy showed that both treatments provided good analgesia which was apparent at the first assessment time (10 minutes) and continued for approximately 10 hours. Only seven patients suffered from unwanted side-effects with only drowsiness/sleepiness and nausea being reported by more than one patient. Over-all analysis of the results showed that there were no significant differences between the two treatments with regard to efficacy and safety.