John Diaper

Impact of intraoperative lung-protective interventions in patients undergoing lung cancer surgery

IntroductionIn lung cancer surgery, large tidal volume and elevated inspiratory pressure are known risk factors of acute lung (ALI). Mechanical ventilation with low tidal volume has been shown to attenuate lung injuries in critically ill patients. In the current study, we assessed the impact of a protective lung ventilation (PLV) protocol in patients undergoing lung cancer resection.MethodsWe performed a secondary analysis of an observational cohort. Demographic, surgical, clinical and outcome data were prospectively collected over a 10-year period. The PLV protocol consisted of small tidal volume, limiting maximal pressure ventilation and adding end-expiratory positive pressure along with recruitment maneuvers. Multivariate analysis with logistic regression was performed and data were compared before and after implementation of the PLV protocol: from 1998 to 2003 (historical group, n = 533) and from 2003 to 2008 (protocol group, n = 558).ResultsBaseline patient characteristics were similar in the two cohorts, except for a higher cardiovascular risk profile in the intervention group. During one-lung ventilation, protocol-managed patients had lower tidal volume (5.3 ± 1.1 vs. 7.1 ± 1.2 ml/kg in historical controls, P = 0.013) and higher dynamic compliance (45 ± 8 vs. 32 ± 7 ml/cmH2O, P = 0.011). After implementing PLV, there was a decreased incidence of acute lung injury (from 3.7% to 0.9%, P < 0.01) and atelectasis (from 8.8 to 5.0, P = 0.018), fewer admissions to the intensive care unit (from 9.4% vs. 2.5%, P < 0.001) and shorter hospital stay (from 14.5 ± 3.3 vs. 11.8 ± 4.1, P < 0.01). When adjusted for baseline characteristics, implementation of the open-lung protocol was associated with a reduced risk of acute lung injury (adjusted odds ratio of 0.34 with 95% confidence interval of 0.23 to 0.75; P = 0.002).ConclusionsImplementing an intraoperative PLV protocol in patients undergoing lung cancer resection was associated with improved postoperative respiratory outcomes as evidence by significantly reduced incidences of acute lung injury and atelectasis along with reduced utilization of intensive care unit resources.

Titrated sedation with propofol or midazolam for flexible bronchoscopy: a randomised trial

In this study, we questioned whether propofol provided clinical benefits compared with midazolam in terms of neuropsychometric recovery, safety profile and patient tolerance. Patients, aged >18 yrs, were randomised to receive midazolam or propofol, given by non-anaesthetist physicians to achieve moderate levels of sedation as assessed by the electroencephalographic bispectral index (BIS; between 70 and 85). The primary end-point was the time delay until recovery of the BIS above 90. Other end-points included a neuropsychometric continuous performance test (CPT), serious respiratory adverse events, patient tolerance and physician satisfaction. Neuropsychometric recovery was improved in the propofol compared to the midazolam group as evidenced by faster normalisation of BIS index (5.4±4.7 min versus 11.7±10.2 min; p = 0.001) and better results at the CPT. In the midazolam group, 15% of patients presented profound sedation precluding CPT completion and one patient required mechanical ventilatory support. Patient tolerance was significantly better in the propofol group, whereas the operator’s assessment was comparable in both groups. Compared with midazolam, propofol provided a higher quality of sedation in terms of neuropsychometric recovery and patient tolerance. BIS-guided propofol administration represents a safe sedation technique that can be performed by the non-anaesthesiologist.

Risk factors of acute kidney injury according to RIFLE criteria after lung cancer surgery.

BACKGROUND Perioperative acute kidney injury (AKI) is associated with increased mortality and morbidity. Our aim was to evaluate the incidence and determinants of AKI using the risk, injury, failure, loss of function, and end-stage kidney disease (RIFLE) criteria in thoracic surgical patients. METHODS We retrospectively analyzed a cohort of patients undergoing lung cancer surgery from 1996 to 2009. Patient management was protocol-driven, and postoperative complications were prospectively collected. The primary outcome was AKI within 3 days after surgery. A variety of patient comorbidities and operative characteristics were evaluated as potential predictors of AKI using a multiple logistic regression model. RESULTS Complete data were obtained from 1,345 patients, and the incidence of AKI was 6.8%. Four independent risk factors for AKI were identified: American Society of Anesthesiologists classes 3 and 4 (odds ratio [OR] 2.60, 95% confidence interval [CI]: 1.03 to 6.55), forced expiratory volume in 1 second (OR 0.55, 95% CI: 0.32 to 0.96), the use of vasopressors (OR 1.015, 95% CI: 0.998 to 1.035), and the duration of anesthesia (OR 1.044, 95% CI: 1.001 to 1.008). Patients who experienced AKI were more frequently admitted to the intensive care unit (24.2% versus 3.5% for patients without AKI, p < 0.05); they had increased mortality (19.8% versus 1.1%, p < 0.05) and a threefold to fourfold higher incidence of cardiopulmonary complications. CONCLUSIONS The RIFLE classification is a valuable tool to assess AKI after lung cancer surgery. The severity of perioperative renal impairment is associated with increased mortality and morbidity.

Impact of aerobic exercise capacity and procedure-related factors in lung cancer surgery

Over the past decades, major progress in patient selection, surgical techniques and anaesthetic management have largely contributed to improved outcome in lung cancer surgery. The purpose of this study was to identify predictors of post-operative cardiopulmonary morbidity in patients with a forced expiratory volume in 1 s <80% predicted, who underwent cardiopulmonary exercise testing (CPET). In this observational study, 210 consecutive patients with lung cancer underwent CPET with completed data over a 9-yr period (2001–2009). Cardiopulmonary complications occurred in 46 (22%) patients, including four (1.9%) deaths. On logistic regression analysis, peak oxygen uptake (peak V′O2) and anaesthesia duration were independent risk factors of both cardiovascular and pulmonary complications; age and the extent of lung resection were additional predictors of cardiovascular complications, whereas tidal volume during one-lung ventilation was a predictor of pulmonary complications. Compared with patients with peak V′O2 >17 mL·kg−1·min−1, those with a peak V′O2 <10 mL·kg−1·min−1 had a four-fold higher incidence of cardiac and pulmonary morbidity. Our data support the use of pre-operative CPET and the application of an intra-operative protective ventilation strategy. Further studies should evaluate whether pre-operative physical training can improve post-operative outcome.

Short-Term Preoperative High-Intensity Interval Training in Patients Awaiting Lung Cancer Surgery: A Randomized Controlled Trial

Introduction: Impairment in aerobic fitness is a potential modifiable risk factor for postoperative complications. In this randomized controlled trial, we hypothesized that a high‐intensity interval training (HIIT) program enhances cardiorespiratory fitness before lung cancer surgery and therefore reduces the risk of postoperative complications. Methods: Patients with operable lung cancer were randomly assigned to usual care (UC) (n = 77) or preoperative rehabilitation based on HIIT (Rehab) (n = 74). Maximal cardiopulmonary exercise testing and the 6‐minute walk test were performed twice before surgery. The primary outcome measure was a composite of death and in‐hospital postoperative complications. Results: The groups were well balanced in terms of patient characteristics. During the preoperative waiting period (median 25 days), the peak oxygen consumption and the 6‐minute walking distance increased (median +15%, interquartile range, 25th to 75 percentile [IQR25%–75%, %] = +9% to +22%, p = 0.003 and +15%, IQR25%–75% = +8% to +28%, p < 0.001, respectively) in the Rehab group, whereas peak oxygen consumption declined in the UC group (median –8%, IQR25%–75% = –16% to 0%], p = 0.005). The primary end point did not differ significantly between the two groups: at least one postoperative complication developed in 27 of the 74 patients (35.5%) in the Rehab group and 39 of 77 patients (50.6%) in the UC group (p = 0.080). Notably, the incidence of pulmonary complications was lower in the Rehab compared with in the UC group (23% versus 44%, p = 0.018), owing to a significant reduction in atelectasis (12.2% versus 36.4%, p < 0.001), and this decrease was accompanied by a shorter length of stay in the postanesthesia care unit (median –7 hours, IQR25%–75% = –4 to –10). Conclusions: In this randomized controlled trial, preoperative HIIT resulted in significant improvement in aerobic performances but failed to reduce early complications after lung cancer resection.

Cardiovascular response to acute normovolaemic haemodilution in patients with severe aortic stenosis: assessment with transoesophageal echocardiography

Using multiplane transoesophageal echocardiography (TOE), we investigated the haemodynamic response to acute normovolaemic haemodilution (ANH) in anaesthetised patients with critical aortic stenosis. Twenty‐eight patients were randomly assigned to ANH or control groups. In the control group, haemodynamic data remained unchanged over a 20‐min period. In the ANH group, haemoglobin levels decreased from a mean (SD) of 134 (7) to 91 (9) g.l−1 (p < 0.001) whereas stroke volume, central venous pressure and left ventricular (LV) end‐diastolic area all increased significantly (mean (SD) +15 (6) ml; +2.0 (1.1) mmHg; +2.1 (0.8) cm2, respectively). During ANH, the accelerated blood flow through the stenotic valve caused an increased loss (SD) in LV stroke work: from 24 (8)% to 30 (10)%), (p < 0.01). Hence, lowering viscosity with ANH resulted in improved venous return, higher cardiac preload and increased stroke volume. However, this adaptive haemodynamic response was limited by less efficient LV stroke work due to dissipation of fluid kinetic energy.

Comparison of cardiac output as assessed by transesophageal echo-Doppler and transpulmonary thermodilution in patients undergoing thoracic surgery

STUDY OBJECTIVE To evaluate the accuracy of cardiac index (CI) as measured by echo-transesophageal Doppler monitoring (echo-TDM) with CI measured by the transpulmonary thermodilution technique. DESIGN Prospective, observational study. SETTING University hospital. PATIENTS 16 patients scheduled for elective lung cancer resection. INTERVENTIONS Patients underwent two-lung ventilation (TLV) and one-lung ventilation (OLV). MEASUREMENTS AND MAIN RESULTS CI measurements were analyzed using Bland-Altman plots. Absolute values of CI as measured by both devices were highly correlated (r(2) ranging from 0.72 to 0.77), as were relative changes in CI after the start of OLV (r(2) = 0.48, P = 0.006). Before, during, and after OLV, TDM-CI biases were 0.46 +/- 0.28 L/min/m(2), 0.25 +/- 0.18 L/min/m(2), and 0.35 +/- 0.29 L/min/m(2), respectively. Limits of agreement remained stable throughout the three measurement periods (range -1.08 to 0.21 L/min/m(2)). The mean percentage error of CI measurements was 21.9% compared with the thermodilution technique. Although no adverse events were reported, 11% of measurement sets were incomplete due to poor signal detection. CONCLUSIONS Echo-TDM is a safe technique, allowing continuous semi-invasive assessment of hemodynamic changes in most patients undergoing open-chest surgery. Doppler-derived CI values showed significant biases and moderate clinical agreement with transpulmonary thermodilution during TLV and OLV.

Preoperative diastolic function predicts the onset of left ventricular dysfunction following aortic valve replacement in high-risk patients with aortic stenosis

IntroductionLeft ventricular (LV) dysfunction frequently occurs after cardiac surgery, requiring inotropic treatment and/or mechanical circulatory support. In this study, we aimed to identify clinical, surgical and echocardiographic factors that are associated with LV dysfunction during weaning from cardiopulmonary bypass (CPB) in high-risk patients undergoing valve replacement for aortic stenosis.MethodsPerioperative data were prospectively collected in 108 surgical candidates with an expected operative mortality ≥9%. All anesthetic and surgical techniques were standardized. Reduced LV systolic function was defined by an ejection fraction <40%. Diastolic function of the LV was assessed using standard Doppler-derived parameters, tissue Doppler Imaging (TDI) and transmitral flow propagation velocity (Vp).ResultsDoppler-derived pulmonary flow indices and TDI could not be obtained in 14 patients. In the remaining 94 patients, poor systolic LV was documented in 14% (n = 12) and diastolic dysfunction in 84% of patients (n = 89), all of whom had Vp <50 cm/s. During weaning from CPB, 38 patients (40%) required inotropic and/or mechanical circulatory support. By multivariate regression analysis, we identified three independent predictors of LV systolic dysfunction: age (Odds ratio [OR] = 1.11; 95% confidence interval (CI), 1.01 to 1.22), aortic clamping time (OR = 1.04; 95% CI, 1.00 to 1.08) and Vp (OR = 0.65; 95% CI, 0.52 to 0.81). Among echocardiographic measurements, Vp was found to be superior in terms of prognostic value and reliability. The best cut-off value for Vp to predict LV dysfunction was 40 cm/s (sensitivity of 72% and specificity 94%). Patients who experienced LV dysfunction presented higher in-hospital mortality (18.4% vs. 3.6% in patients without LV dysfunction, P = 0.044) and an increased incidence of serious cardiac events (81.6 vs. 28.6%, P < 0.001).ConclusionsThis study provides the first evidence that, besides advanced age and prolonged myocardial ischemic time, LV diastolic dysfunction characterized by Vp ≤ 40 cm/sec identifies patients who will require cardiovascular support following valve replacement for aortic stenosis.

Titrated Sedation with Propofol for Medical Thoracoscopy: A Feasibility and Safety Study

Background: Bispectral index (BIS) is a valuable tool for assessing the depth of sedation and guiding the administration of sedative drugs. We previously demonstrated the benefits of BIS-guided propofol sedation in patients undergoing flexible bronchoscopy. Objective: To examine the feasibility and safety profile of propofol sedation in patients undergoing medical thoracoscopy (MT). Methods: Patients undergoing MT for diagnostic evaluation or treatment of pleuropulmonary diseases were enrolled over a 2-year period. Nurses and chest physicians were trained by anesthetists to provide analgosedation, to detect and correct cardiopulmonary disturbances. The level of sedation was optimized individually by titrating the propofol infusion according to the BIS and clinical evaluation. Patients’ clinical data, procedure time, medications and any adverse events were recorded. Results: Fifty-three patients (60% male) with a median age of 62 years (range 19–84 years) underwent MT. The operative procedure lasted a median time of 28 min (range 9–112 min). The median doses of anesthetic drugs were 145 mg of propofol (range 20–410 mg) and 84 µg of fentanyl (range 0–225 µg). Hemodynamic disturbances occurred in 39 patients (bradycardia n = 4, tachycardia n = 12, hypotension n = 34) and required drug administration in only 4 cases. Hypoxemic events (n = 4) resolved upon gentle patient stimulation (verbal command, chin lift, oral cannula). All patients could be discharged from the recovery unit within 105 min after the procedure. Conclusions: BIS-guided propofol sedation is a safe method that might replace midazolam sedation in MT and can be managed by well-trained nonanesthesiologist personnel.

Clinical Review: Management of weaning from cardiopulmonary bypass after cardiac surgery

A sizable number of cardiac surgical patients are difficult to wean off cardiopulmonary bypass (CPB) as a result of structural or functional cardiac abnormalities, vasoplegic syndrome, or ventricular dysfunction. In these cases, therapeutic decisions have to be taken quickly for successful separation from CPB. Various crisis management scenarios can be anticipated which emphasizes the importance of basic knowledge in applied cardiovascular physiology, knowledge of pathophysiology of the surgical lesions as well as leadership, and communication between multiple team members in a high-stakes environment. Since the mid-90s, transoesophageal echocardiography has provided an opportunity to assess the completeness of surgery, to identify abnormal circulatory conditions, and to guide specific medical and surgical interventions. However, because of the lack of evidence-based guidelines, there is a large variability regarding the use of cardiovascular drugs and mechanical circulatory support at the time of weaning from the CPB. This review presents key features for risk stratification and risk modulation as well as a standardized physiological approach to achieve successful weaning from CPB.