Alexandre Ouattara

Doppler resistive index to reflect regulation of renal vascular tone during sepsis and acute kidney injury

IntroductionRenal resistive index (RI), determined by Doppler ultrasonography, directly reveals and quantifies modifications in renal vascular resistance. The aim of this study was to evaluate if mean arterial pressure (MAP) is determinant of renal RI in septic, critically ill patients suffering or not from acute kidney injury (AKI).MethodsThis prospective observational study included 96 patients. AKI was defined according to RIFLE criteria and transient or persistent AKI according to renal recovery within 3 days.ResultsMedian renal RIs were 0.72 (0.68-0.75) in patients without AKI and 0.76 (0.72-0.80) in patients with AKI (P=0.001). RIs were 0.75 (0.72-0.79) in transient AKI and 0.77 (0.70-0.80) in persistent AKI (P=0.84). RI did not differ in patients given norepinephrine infusion and was not correlated with norepinephrine dose. RI was correlated with MAP (ρ= -0.47; P=0.002), PaO2/FiO2 ratio (ρ= -0.33; P=0.04) and age (ρ=0.35; P=0.015) only in patients without AKI.ConclusionsA poor correlation between renal RI and MAP, age, or PaO2/FiO2 ratio was found in septic and critically ill patients without AKI compared to patients with AKI. These findings suggest that determinants of RI are multiple. Renal circulatory response to sepsis estimated by Doppler ultrasonography cannot reliably be predicted simply from changes in systemic hemodynamics. As many factors influence its value, the interest in a single RI measurement at ICU admission to determine optimal MAP remains uncertain.

Effect of Levosimendan on Low Cardiac Output Syndrome in Patients With Low Ejection Fraction Undergoing Coronary Artery Bypass Grafting With Cardiopulmonary Bypass: The LICORN Randomized Clinical Trial

Importance Low cardiac output syndrome after cardiac surgery is associated with high morbidity and mortality in patients with impaired left ventricular function. Objective To assess the ability of preoperative levosimendan to prevent postoperative low cardiac output syndrome. Design, Setting, and Participants Randomized, double-blind, placebo-controlled trial conducted in 13 French cardiac surgical centers. Patients with a left ventricular ejection fraction less than or equal to 40% and scheduled for isolated or combined coronary artery bypass grafting with cardiopulmonary bypass were enrolled from June 2013 until May 2015 and followed during 6 months (last follow-up, November 30, 2015). Interventions Patients were assigned to a 24-hour infusion of levosimendan 0.1 µg/kg/min (n = 167) or placebo (n = 168) initiated after anesthetic induction. Main Outcomes and Measures Composite end point reflecting low cardiac output syndrome with need for a catecholamine infusion 48 hours after study drug initiation, need for a left ventricular mechanical assist device or failure to wean from it at 96 hours after study drug initiation when the device was inserted preoperatively, or need for renal replacement therapy at any time postoperatively. It was hypothesized that levosimendan would reduce the incidence of this composite end point by 15% in comparison with placebo. Results Among 336 randomized patients (mean age, 68 years; 16% women), 333 completed the trial. The primary end point occurred in 87 patients (52%) in the levosimendan group and 101 patients (61%) in the placebo group (absolute risk difference taking into account center effect, −7% [95% CI, −17% to 3%]; P = .15). Predefined subgroup analyses found no interaction with ejection fraction less than 30%, type of surgery, and preoperative use of &bgr;-blockers, intra-aortic balloon pump, or catecholamines. The prevalence of hypotension (57% vs 48%), atrial fibrillation (50% vs 40%), and other adverse events did not significantly differ between levosimendan and placebo. Conclusions and Relevance Among patients with low ejection fraction who were undergoing coronary artery bypass grafting with cardiopulmonary bypass, levosimendan compared with placebo did not result in a significant difference in the composite end point of prolonged catecholamine infusion, use of left ventricular mechanical assist device, or renal replacement therapy. These findings do not support the use of levosimendan for this indication. Trial Registration EudraCT Number: 2012-000232-25; clinicaltrials.gov Identifier: NCT02184819

Kinetic eGFR and Novel AKI Biomarkers to Predict Renal Recovery

BACKGROUND AND OBJECTIVES Prompt recognition of severe renal impairment could improve the early management of critically ill patients. We compared the value of kinetic eGFR, plasma neutrophil gelatinase-associated lipocalin (NGAL), and urine tissue inhibitor of metalloproteinase-2 and urine insulin-like growth factor-binding protein 7 ([TIMP-2]*[IGFBP7]) in predicting short-term recovery from AKI and major adverse kidney events. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS During the 6-month study period, 245 patients were admitted to our intensive care unit. This study included 57 consecutive patients presenting with AKI within the first 24 hours after admission. AKI markers were evaluated at inclusion (day 0) and 24 hours later (day 1). Kinetic eGFR was calculated on day 1 according to serum creatinine evolution. Renal recovery was defined as normalization of serum creatinine with reversal of oliguria within 48 hours. Major adverse kidney events included death, need for RRT, or persistence of renal dysfunction at hospital discharge. RESULTS Plasma NGAL and [TIMP-2]*[IGFBP7] predicted renal recovery, with area under the receiver-operating characteristic curve (AUC-ROC) values between 0.70 and 0.79 at inclusion. Although plasma NGAL values frequently reached the maximal measurement range, their decrease on day 1 predicted recovery. The kinetic eGFR calculation after initial resuscitation provided the best AUC-ROC value for renal recovery, at 0.87. The best predictions for major adverse kidney events were provided by [TIMP-2]*[IGFBP7] and kinetic eGFR (equal AUC-ROCs of 0.81). Combining AKI markers in addition to clinical prediction models improved the discrimination and reclassification of patients who will recover from AKI or suffer from major adverse kidney events. CONCLUSIONS Biomarkers of kidney damage predicted short-term renal recovery and major adverse kidney events for an unselected cohort of critically ill patients. Calculating the kinetic eGFR imposed a delay after initial resuscitation but provided a good diagnostic and prognostic approach. The utility of functional and damage AKI marker combinations in addition to clinical information requires validation in larger prospective studies.

Neuro-ventilatory efficiency during weaning from mechanical ventilation using neurally adjusted ventilatory assist

BACKGROUND Neuro-ventilatory efficiency (NVE), defined as the tidal volume to electrical diaphragm-activity ratio (VT/EAdi) at the beginning and end of the weaning process after acute hypoxaemic respiratory failure, may provide valuable information about patient recovery. METHODS This observational study included 12 patients breathing with neurally adjusted ventilatory assist (NAVA). When a spontaneous breathing trial (SBT) with pressure support of 7 cm H2O and PEEP was unsuccessful, NAVA was used and the level was adjusted to obtain an EAdi of ∼60% of maximal EAdi during SBT. VT and EAdi were recorded continuously. We compared changes in NVE between NAVA and SBT at the first failed and first successful SBT. RESULTS When patients were switched from NAVA to SBT, NVE was significantly reduced during both unsuccessful and successful SBT (-56 and -38%, respectively); however, this reduction was significantly lower when SBT was successful (P=0.01). Between the first and last day of weaning, we observed that NVE decreased with NAVA [40.6 (27.7-89.5) vs 28.8 (18.6-46.7); P=0.002] with a significant decrease in NAVA level, whereas it remained unchanged during SBT [15.4 (10.7-39.1) vs 19.5 (11.6-29.6); P=0.50] with significant increases in both EAdi and VT and no difference in respiratory rhythm. CONCLUSIONS These results suggest that in patients after respiratory failure and prolonged mechanical ventilation, changes in VT and NVE, between SBTs are indicative of patient recovery. Larger clinical trials are needed to clarify whether changes in NVE reliably predict weaning in patients ventilated with NAVA.

Reducing tidal volume and increasing positive end-expiratory pressure with constant plateau pressure during one-lung ventilation: effect on oxygenation

BACKGROUND It is no longer safe to use large tidal volumes (V(T)) (>8 ml kg(-1)) for one-lung ventilation (OLV), and limiting plateau pressure should be a major objective. Due to the specificity of OLV, the use of positive end-expiratory pressure (PEEP) remains controversial. This study determined whether at the same low plateau pressure, reducing V(T) and increasing PEEP were not inferior to larger V(T) and lower PEEP ventilation in terms of oxygenation. METHODS This prospective, randomized, non-inferiority, cross-over trial included 88 patients undergoing open thoracotomy who received two successive ventilatory strategies in random order: V(T) (8 ml kg(-1) of ideal body weight) with low PEEP (5 cm H(2)O), or low V(T) (5 ml kg(-1)) with a high PEEP. Respiratory rate and PEEP were, respectively, adjusted to maintain constant ventilation and plateau pressure. The primary endpoint was the ratio under each ventilatory strategy. RESULTS The non-inferiority of low-V(T) ventilation could not be established. The mean adjusted ratio was lower overall during low-V(T) ventilation, and differences between the two ventilatory modes varied significantly according to baseline (T0). Decreased oxygenation during low V(T) was smaller when baseline values were low. Systolic arterial pressure was not lower during low-V(T) ventilation. CONCLUSION During OLV, lowering V(T) and increasing PEEP, with the same low plateau pressure, reduced oxygenation compared with larger V(T) and lower PEEP. This strategy may reduce the risk of lung injury, but needs to be investigated further.

Pressure-controlled ventilation and intrabronchial pressure during one-lung ventilation†

BACKGROUND Pressure-controlled ventilation (PCV) has been suggested to reduce peak airway pressure (P(peak)) and intrapulmonary shunt during one-lung ventilation (OLV) when compared with volume-controlled ventilation (VCV). At the same tidal volume (V(T)), the apparent difference in P(peak) is mainly related to the presence of a double-lumen tracheal tube. We tested the hypothesis that the decrease in P(peak) observed in the breathing circuit is not necessarily associated with a decrease in the bronchus of the dependent lung. METHODS This observational study included 15 consecutive subjects who were ventilated with VCV followed by PCV at constant V(T). Airway pressure was measured simultaneously in the breathing circuit and main bronchus of the dependent lung after 20 min of ventilation. RESULTS PCV induced a significant decrease in P(peak) [mean (sd)] measured in the breathing circuit [36 (4) to 26 (3) cm H(2)0, P<0.0001] and in the bronchus [23 (4) to 22 (3) cm H(2)O, P=0.01]. However, the interaction (ventilatory mode x site of measurement) revealed that the decrease in P(peak) was significantly higher in the circuit (P<0.0001). Although the mean percentage decrease in P(peak) was significant at both sites, the decrease was significantly lower in the bronchus [5 (6)% vs 29 (3)%, P<0.0001]. CONCLUSIONS During PCV for OLV, the decrease in P(peak) is observed mainly in the respiratory circuit and is probably not clinically relevant in the bronchus of the dependent lung. This challenges the common clinical perception that PCV offers an advantage over VCV during OLV by reducing bronchial P(peak).

Cystic fibrosis patient awaiting lung transplantation ventilated with neurally adjusted ventilatory assist

Editor—We investigated, in a double-blind randomized control study, the effect of a ketamine gargle to attenuate postoperative sore throat (POST) in 44 adult ASA I or II patients undergoing elective gynaecological procedures. The patients had 30 s gargling with either 20 ml of normal saline (Group C: control, n1⁄422) or ketamine 40 mg in 20 ml normal saline (Group K: ketamine, n1⁄422). Anaesthesia was induced with fentanyl, propofol, and rocuronium, 5–10 min after gargling. Maintenance of anaesthesia was with oxygen–air mixture and sevoflurane. Titrated boluses of morphine were given according to clinical requirements during surgery. The same anaesthetist performed all intubations and extubations. During surgery, blood samples were collected at intervals for ketamine and norketamine analysis. At the end of the study period, serum samples from five patients in Group K, randomly selected, were assayed by liquid chromatography and mass spectrometry. After extubation, POST was assessed at 0 (on arrival at the post-anaesthetic care unit), 2, and 24 h using a four-point grading scale (none, 0; mild, 1; moderate, 2; and severe, 3). POST was significantly reduced in Group K compared with Group C (P,0.05) at 0 and 2 h after surgery but not at 24 h (P1⁄40.498). There was significantly less moderate-to-severe POST in Group K at 0 h. Ketamine gargle has been reported to attenuate POST for 24 h post-surgery. We observed significant reduction in POST at 0 and 2 h post-surgery but not at 24 h. The reported ketamine level to relieve tourniquet pain after an i.v. bolus was .100 ng ml. The analgesic effect from oral administration of ketamine was at a lower mean plasma concentration of ketamine 40 ng ml, presumably due to the higher norketamine levels (160 ng ml). In this study, blood samples were obtained during intraoperatively, but POST was assessed post-surgery when ketamine concentrations are likely to be lower. Systemic absorption and the possibility of swallowing the residual solution would contribute to the ketamine in the blood. The highest average ketamine and norketamine concentrations, 16.16 and 11.43 ng ml, respectively (Table 1), were detected during surgery but would have decreased after the surgery. These low levels suggested that it was unlikely that systemic absorption played a major role for the reduction of POST. A topical effect is possible. We conclude that pre-induction ketamine gargle can attenuate POST in the early postoperative period. Drug levels detected were much lower than reported measurements for analgesia after oral and parenteral administration.

The Use of Impella 2.5 in Severe Refractory Cardiogenic Shock Complicating an Acute Myocardial Infarction

OBJECTIVES To investigate the outcome of patients with acute myocardial infarction (AMI) complicated by refractory cardiogenic shock (CS) who underwent mechanical circulatory support with Impella 2.5. BACKGROUND AMI complicated by CS remains a highly fatal condition. A potent and minimally invasive left ventricular assist device might improve patient outcomes. METHODS We analyzed the procedural characteristics and outcomes of 22 consecutive patients who underwent, between July 2008 and December 2012, a percutaneous coronary intervention and Impella 2.5 support for AMI complicated by CS refractory to first-line therapy with inotropes and/or Intra-aortic balloon pump. RESULTS In this analysis, patients were relatively young with a mean age of 57.9 ± 11.6 year old and 59.1% were male. The majority of patients (77.3%) were admitted in CS and 40.9% sustained cardiac arrest prior to admission. Hemodynamics improved significantly upon initiation of support, end-organ and tissue perfusion improved subsequently demonstrated by a significant decrease in lactate levels from 6.37 ± 5.3 mmol/L to 2.41 ± 2.1 mmo/L, (P =  0.008) after 2 days of support. Thirteen (59.1%) patients were successfully weaned-off Impella 2.5 and 4 (18.2%) were transitioned to another device. We observed a functional recovery of the left ventricle when compared to baseline (43 ± 10% vs. 27 ± 9%, P < 0.0001). The survival rate at 6 months and 1 year was 59.1% and 54.5%, respectively. CONCLUSION Impella 2.5 was initiated as a last resort therapy to support very sick patients with refractory CS after failed conventional therapy. The use of the device yielded favorable short and mid-term survival results with recovery being the most frequently observed outcome.

Fresh‐frozen plasma transfusion did not reduce 30‐day mortality in patients undergoing cardiopulmonary bypass cardiac surgery with excessive bleeding: the PLASMACARD multicenter cohort study

During on‐pump cardiac surgery, hemorrhagic complications occur frequently. Fresh‐frozen plasma (FFP) is widely transfused to provide coagulation factors. Yet, no randomized clinical trial has demonstrated its benefits on mortality. We assessed the relationship between therapeutic transfusion of FFP and 30‐day mortality in cardiac surgery patients suffering from excessive bleeding in a prospective cohort study.

How Long Is a Transurethral Catheter Necessary in Patients Undergoing Thoracotomy and Receiving Thoracic Epidural Analgesia? Literature Review

DESPITE THE AGING POPULATION and new lung cancer cases being on the rise, clinicians are forced to be more efficient and more productive without additional resources. Fast-track pathways have been described showing outstanding results, such as a faster recovery process and shorter length of hospital stay,but mainly for abdominal and orthopedic surgeries. Although enhanced recovery paths might seem to be an excellent option to solve this problem, there is a scarcity of trials in thoracic surgery in general on this subject. Therefore, it is essential to implement recovery pathway programs for patients undergoing thoracic surgery. Thoracic epidural analgesia (TEA) is the gold standard to relieve pain after thoracotomy because of its association with severe pain. Thus, a crucial point to implement a fast-track pathway in thoracic surgery is to offer TEA. It reduces significantly the incidence of postoperative morbidity compared with other types of analgesia. In contrast, TEA encompasses important side effects. Postoperative urinary retention (POUR) is one of the most frequent, with an average incidence of 26%. To avoid this complication, it is a common practice to place a transurethral catheter, as long as the epidural is in situ and functioning well. Nevertheless, a urinary bladder catheter impedes early ambulation and can lead to urinary tract infection (UTI), which increases patients’ hospital length of stay and governmental costs. Recent studies have reported that transurethral catheters can be removed earlier safely in thoracic surgery patients. Hence, the goal of the present review was to determine when is the most appropriate timing to remove the bladder catheter in patients undergoing thoracic surgery receiving TEA. This paper reviews the literature to provide recommendations from experts’ opinions for both the appropriate removal period of the indwelling bladder catheter and the management of POUR for patients scheduled for thoracotomy receiving working TEA. This review aims to contribute to the building of a fast-track pathway for patients undergoing thoracotomy.