Benefits of intratracheal and extrathoracic high-frequency percussive ventilation in a model of capnoperitoneum

Abdominal inflation with CO2 is used to facilitate laparoscopic surgeries, however, providing adequate mechanical ventilation in this scenario is of major importance during anesthesia management. We characterized high-frequency percussive ventilation (HFPV) in protecting from the gas exchange and respiratory mechanical impairments during capnoperitoneum. In addition, we aimed to assess the difference between conventional pressure-controlled mechanical ventilation (CMV) and HFPV modalities generating the high-frequency signal intratracheally (HFPVi) or extrathoracally (HFPVe). Anesthetized rabbits (n = 16) were mechanically ventilated by random sequences of CMV, HFPVi, and HFPVe. The ventilator superimposed the conventional waveform with two high-frequency signals (5 Hz and 10 Hz) during intratracheal HFPV (HFPVi) and HFPV with extrathoracic application of oscillatory signals through a sealed chest cuirass (HFPVe). Lung oxygenation index ([Formula: see text]/[Formula: see text]), arterial partial pressure of carbon dioxide ([Formula: see text]), intrapulmonary shunt (Qs/Qt), and respiratory mechanics were assessed before abdominal inflation, during capnoperitoneum, and after abdominal deflation. Compared with CMV, HFPVi with additional 5-Hz oscillations during capnoperitoneum resulted in higher [Formula: see text]/[Formula: see text], lower [Formula: see text], and decreased Qs/Qt. These improvements were smaller but remained significant during HFPVi with 10 Hz and HFPVe with either 5 or 10 Hz. The ventilation modes did not protect against capnoperitoneum-induced deteriorations in respiratory tissue mechanics. These findings suggest that high-frequency oscillations combined with conventional pressure-controlled ventilation improved lung oxygenation and CO2 removal in a model of capnoperitoneum. Compared with extrathoracic pressure oscillations, intratracheal generation of oscillatory pressure bursts appeared more effective. These findings may contribute to the optimization of mechanical ventilation during laparoscopic surgery.NEW & NOTEWORTHY The present study examines an alternative and innovative mechanical ventilation modality in improving oxygen delivery, CO2 clearance, and respiratory mechanical abnormalities in a clinically relevant experimental model of capnoperitoneum. Our data reveal that high-frequency oscillations combined with conventional ventilation improve gas exchange, with intratracheal oscillations being more effective than extrathoracic oscillations in this clinically relevant translational model.

New Noninvasive Method for the Assessment of Central Venous Oxygen Saturations in Critically Ill Patients

OBJECTIVES

To compare noninvasive external jugular vein oxygen saturations (SjvO2) and central venous oxygen saturation (ScvO2) from a blood sample in patients admitted to the intensive care unit.

DESIGN

A prospective, comparative, monocentric clinical trial design was used.

SETTING

The study was performed in the Department of Anaesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University Hospitals of Geneva (Switzerland).

PARTICIPANTS

A total of 79 patients were enrolled; patients with confirmed COVID-19 infection requiring invasive mechanical ventilation (patients with COVID-19, n = 36) and patients after liver transplantation (posttransplant patients, n = 43).

INTERVENTIONS

Simultaneous measurement of SjvO2 by near-infrared spectroscopy and ScvO2 from central venous blood samples using a blood gas analyzer in stable hemodynamic conditions.

MEASUREMENTS AND MAIN RESULTS

A strong linear correlation was evidenced in both the COVID-19 and posttransplant patient groups between the 2 modalities. The Bland-Altman analysis showed low bias in accordance with low percentage error in both groups (0.57% and 8.09% for patients with COVID-19; 0.00% and 13.72% for posttransplant patients).

CONCLUSIONS

Central venous oxygen saturation can be estimated reasonably by the continuous noninvasive measurement of SjvO2 using near-infrared spectroscopy.

Lung recruitment by continuous negative extra-thoracic pressure support following one-lung ventilation: an experimental study

Lung recruitment maneuvers following one-lung ventilation (OLV) increase the risk for the development of acute lung injury. The application of continuous negative extrathoracic pressure (CNEP) is gaining interest both in intubated and non-intubated patients. However, there is still a lack of knowledge on the ability of CNEP support to recruit whole lung atelectasis following OLV. We investigated the effects of CNEP following OLV on lung expansion, gas exchange, and hemodynamics. Ten pigs were anesthetized and mechanically ventilated with pressure-regulated volume control mode (PRVC; FiO₂: 0.5, Fr: 30-35/min, VT: 7 mL/kg, PEEP: 5 cmH₂O) for 1 hour, then baseline (BL) data for gas exchange (arterial partial pressure of oxygen, PaO₂; and carbon dioxide, PaCO₂), ventilation and hemodynamical parameters and lung aeration by electrical impedance tomography were recorded. Subsequently, an endobronchial blocker was inserted, and OLV was applied with a reduced VT of 5 mL/kg. Following a new set of measurements after 1 h of OLV, two-lung ventilation was re-established, combining PRVC (VT: 7 mL/kg) and CNEP (-15 cmH₂O) without any hyperinflation maneuver and data collection was then repeated at 5 min and 1 h. Compared to OLV, significant increases in PaO₂ (154.1 ± 13.3 vs. 173.8 ± 22.1) and decreases in PaCO₂ (52.6 ± 11.7 vs. 40.3 ± 4.5 mmHg, p < 0.05 for both) were observed 5 minutes following initiation of CNEP, and these benefits in gas exchange remained after an hour of CNEP. Gradual improvements in lung aeration in the non-collapsed lung were also detected by electrical impedance tomography (p < 0.05) after 5 and 60 min of CNEP. Hemodynamics and ventilation parameters remained stable under CNEP. Application of CNEP in the presence of whole lung atelectasis proved to be efficient in improving gas exchange via recruiting the lung without excessive airway pressures. These benefits of combined CNEP and positive pressure ventilation may have particular value in relieving atelectasis in the postoperative period of surgical procedures requiring OLV.

Benefit of Flow-Controlled Over Pressure-Regulated Volume Control Mode During One-Lung Ventilation: A Randomized Experimental Crossover Study

BACKGROUND

Application of a ventilation modality that ensures adequate gas exchange during one-lung ventilation (OLV) without inducing lung injury is of paramount importance. Due to its beneficial effects on respiratory mechanics and gas exchange, flow-controlled ventilation (FCV) may be considered as a protective alternative mode of traditional pressure- or volume-controlled ventilation during OLV. We investigated whether this new modality provides benefits compared with conventional ventilation modality for OLV.

METHODS

Ten pigs were anaesthetized and randomly assigned in a crossover design to be ventilated with FCV or pressure-regulated volume control (PRVC) ventilation. Arterial partial pressure of oxygen (Pa o2 ), carbon dioxide (Pa co2 ), ventilation and hemodynamical parameters, and lung aeration measured by electrical impedance tomography were assessed at baseline and 1 hour after the application of each modality during OLV using an endobronchial blocker.

RESULTS

Compared to PRVC, FCV resulted in increased Pa o2 (153.7 ± 12.7 vs 169.9 ± 15.0 mm Hg; P = .002) and decreased Pa co2 (53.0 ± 11.0 vs 43.2 ± 6.0 mm Hg; P < .001) during OLV, with lower respiratory elastance (103.7 ± 9.5 vs 77.2 ± 10.5 cm H 2 O/L; P < .001) and peak inspiratory pressure values (27.4 ± 1.9 vs 22.0 ± 2.3 cm H 2 O; P < .001). No differences in lung aeration or hemodynamics could be detected between the 2 ventilation modalities.

CONCLUSIONS

The application of FCV in OLV led to improvement in gas exchange and respiratory elastance with lower ventilatory pressures. Our findings suggest that FCV may offer an optimal, protective ventilation modality for OLV.

Distribution of ventilation and oxygenation in surgical obese patients ventilated with high versus low positive end-expiratory pressure: A substudy of a randomised controlled trial

BACKGROUND

Intra-operative ventilation using low/physiological tidal volume and positive end-expiratory pressure (PEEP) with periodic alveolar recruitment manoeuvres (ARMs) is recommended in obese surgery patients.

OBJECTIVES

To investigate the effects of PEEP levels and ARMs on ventilation distribution, oxygenation, haemodynamic parameters and cerebral oximetry.

DESIGN

A substudy of a randomised controlled trial.

SETTING

Tertiary medical centre in Geneva, Switzerland, between 2015 and 2018.

PATIENTS

One hundred and sixty-two patients with a BMI at least 35 kg per square metre undergoing elective open or laparoscopic surgery lasting at least 120 min.

INTERVENTION

Patients were randomised to PEEP of 4 cmH 2 O ( n  = 79) or PEEP of 12 cmH 2 O with hourly ARMs ( n  = 83).

MAIN OUTCOME MEASURES

The primary endpoint was the fraction of ventilation in the dependent lung as measured by electrical impedance tomography. Secondary endpoints were the oxygen saturation index (SaO 2 /FIO 2 ratio), respiratory and haemodynamic parameters, and cerebral tissue oximetry.

RESULTS

Compared with low PEEP, high PEEP was associated with smaller intra-operative decreases in dependent lung ventilation [-11.2%; 95% confidence interval (CI) -8.7 to -13.7 vs. -13.9%; 95% CI -11.7 to -16.5; P  = 0.029], oxygen saturation index (-49.6%; 95% CI -48.0 to -51.3 vs. -51.3%; 95% CI -49.6 to -53.1; P  < 0.001) and a lower driving pressure (-6.3 cmH 2 O; 95% CI -5.7 to -7.0). Haemodynamic parameters did not differ between the groups, except at the end of ARMs when arterial pressure and cardiac index decreased on average by -13.7 mmHg (95% CI -12.5 to -14.9) and by -0.54 l min -1  m -2 (95% CI -0.49 to -0.59) along with increased cerebral tissue oximetry (3.0 and 3.2% on left and right front brain, respectively).

CONCLUSION

In obese patients undergoing abdominal surgery, intra-operative PEEP of 12 cmH 2 O with periodic ARMs, compared with intra-operative PEEP of 4 cmH 2 O without ARMs, slightly redistributed ventilation to dependent lung zones with minor improvements in peripheral and cerebral oxygenation.

TRIAL REGISTRATION

NCT02148692, https://clinicaltrials.gov/ct2.

Invasive and non-invasive assessment of macro- and micro-circulatory effects of vasopressors during sevoflurane anesthesia in a pediatric experimental model: A randomized trial

BACKGROUND

While non-invasive assessment of macro- and micro-circulation has the promise to optimize anesthesia management, evidence is lacking for the relationship between invasive and non-invasive measurements of cardiac output and microcirculatory indices.

AIMS

We aimed to compare the abilities of non-invasive techniques to detect changes in macro- and micro-circulation following deep anesthesia and subsequent restoration of the compromised hemodynamic by routinely used vasopressors in a randomized experimental study.

METHODS

A 20%-25% drop in mean arterial pressure was induced by sevoflurane in anesthetized mechanically ventilated just-weaned piglets (n = 12) prior to the administration of vasopressors in random order (dopamine, ephedrine, noradrenaline, and phenylephrine). Simultaneous transpulmonary thermodilution cardiac output assessment with the invasive pulse index continuous contour (PiCCO) method was compared with non-invasive estimates obtained with electrical conductivity (ICON) and echo Doppler (Cardio Q). Changes in microcirculation were characterized by sublingual red blood cell velocity, jugular cerebral venous oxygen saturation, and arterial lactate.

MAIN OUTCOME MEASURES

Cardiac output indices obtained by invasive and non-invasive methods.

RESULTS

Changes in cardiac output measured invasively and non-invasively correlated significantly after sevoflurane (r = .78, p = .003 and r = .76, p = .006 between PiCCO and ICON or Cardio Q, respectively). Following the administration of vasopressors, invasive and non-invasive cardiac output assessments were unrelated with significant correlations observed only between PiCCO and ICON after dopamine and ephedrine. Sevoflurane-induced hypotension decreased jugular cerebral venous oxygen saturation significantly and was recovered by all vasopressors. Sevoflurane and vasopressors had no effect on red blood cell velocity, which increased only after dopamine. No consistent changes in lactate were observed during the study period.

CONCLUSIONS

The results of this study suggest that non-invasive cardiac output measurements may not accurately reflect changes in macrocirculation after hemodynamic optimization by vasopressors. Due to the incoherence between macro- and micro-circulation, monitoring microcirculation is essential to guide patient management.

Effect of body position on the redistribution of regional lung aeration during invasive and non-invasive ventilation of COVID-19 patients

Severe COVID-19-related acute respiratory distress syndrome (C-ARDS) requires mechanical ventilation. While this intervention is often performed in the prone position to improve oxygenation, the underlying mechanisms responsible for the improvement in respiratory function during invasive ventilation and awake prone positioning in C-ARDS have not yet been elucidated. In this prospective observational trial, we evaluated the respiratory function of C-ARDS patients while in the supine and prone positions during invasive (n = 13) or non-invasive ventilation (n = 15). The primary endpoint was the positional change in lung regional aeration, assessed with electrical impedance tomography. Secondary endpoints included parameters of ventilation and oxygenation, volumetric capnography, respiratory system mechanics and intrapulmonary shunt fraction. In comparison to the supine position, the prone position significantly increased ventilation distribution in dorsal lung zones for patients under invasive ventilation (53.3 ± 18.3% vs. 43.8 ± 12.3%, percentage of dorsal lung aeration ± standard deviation in prone and supine positions, respectively; p = 0.014); whereas, regional aeration in both positions did not change during non-invasive ventilation (36.4 ± 11.4% vs. 33.7 ± 10.1%; p = 0.43). Prone positioning significantly improved the oxygenation both during invasive and non-invasive ventilation. For invasively ventilated patients reduced intrapulmonary shunt fraction, ventilation dead space and respiratory resistance were observed in the prone position. Oxygenation is improved during non-invasive and invasive ventilation with prone positioning in patients with C-ARDS. Different mechanisms may underly this benefit during these two ventilation modalities, driven by improved distribution of lung regional aeration, intrapulmonary shunt fraction and ventilation-perfusion matching. However, the differences in the severity of C-ARDS may have biased the sensitivity of electrical impedance tomography when comparing positional changes between the protocol groups.Trial registration: ClinicalTrials.gov (NCT04359407) and Registered 24 April 2020, https://clinicaltrials.gov/ct2/show/NCT04359407 .

Three-Minute Diagnostic Assessment for Delirium using the Confusion Assessment Method (3D-CAM): French translation and cultural adaptation

PURPOSE

The routine use of validated diagnostic instruments is key to identifying delirious patients early and expediting care. The 3-Minute Diagnostic Assessment for Delirium using the Confusion Assessment Method (3D-CAM) instrument is a brief, easy to use, sensitive, and specific delirium assessment tool for hospitalized patients. We aimed to translate the original English version into French, and then adapt it to older high-risk patients.

METHODS

Translation and adaptation of the questionnaire were guided by an expert committee and the 3D-CAM instrument developer. During the translation phase, we achieved semantic and conceptual equivalence of the instrument by conducting forward and backward translations. During the adaptation phase, we assessed the face validity, clarity of wording, and ease of use of the translated questionnaire by administering it to 30 patients and their caregivers in peri-interventional and medical intermediate care units. During both phases, we used qualitative (goal and adequacy of the questionnaire) and quantitative (Sperber score, clarity score) criteria.

RESULTS

Translation: four items were judged inadequate and were revised until all reached a Sperber score of < 3/7. Face validity: 91% of patients thought the questionnaire was designed to assess memory, thoughts, or reasoning. Clarity: eight items required adjustments until all scored ≥ 9/10 for clarity. Ease of use: all bedside caregivers reported that the questionnaire was easy to complete after receiving brief instructions.

CONCLUSIONS

We produced a culturally adapted French version of the 3D-CAM instrument that is well understood and well-received by older high-risk patients and their caregivers.

Flow-controlled ventilation maintains gas exchange and lung aeration in a pediatric model of healthy and injured lungs: A randomized cross-over experimental study

Flow-controlled ventilation (FCV) is characterized by a constant flow to generate active inspiration and expiration. While the benefit of FCV on gas exchange has been demonstrated in preclinical and clinical studies with adults, the value of this modality for a pediatric population remains unknown. Thus, we aimed at observing the effects of FCV as compared to pressure-regulated volume control (PRVC) ventilation on lung mechanics, gas exchange and lung aeration before and after surfactant depletion in a pediatric model. Ten anesthetized piglets (10.4 ± 0.2 kg) were randomly assigned to start 1-h ventilation with FCV or PRVC before switching the ventilation modes for another hour. This sequence was repeated after inducing lung injury by bronchoalveolar lavage and injurious ventilation. The primary outcome was respiratory tissue elastance. Secondary outcomes included oxygenation index (PaO₂/FiO₂), PaCO₂, intrapulmonary shunt (Qs/Qt), airway resistance, respiratory tissue damping, end-expiratory lung volume, lung clearance index and lung aeration by chest electrical impedance tomography. Measurements were performed at the end of each protocol stage. Ventilation modality had no effect on any respiratory mechanical parameter. Adequate gas exchange was provided by FCV, similar to PRVC, with sufficient CO₂ elimination both in healthy and surfactant-depleted lungs (39.46 ± 7.2 mmHg and 46.2 ± 11.4 mmHg for FCV; 36.0 ± 4.1 and 39.5 ± 4.9 mmHg, for PRVC, respectively). Somewhat lower PaO₂/FiO₂ and higher Qs/Qt were observed in healthy and surfactant depleted lungs during FCV compared to PRVC (p < 0.05, for all). Compared to PRVC, lung aeration was significantly elevated, particularly in the ventral dependent zones during FCV (p < 0.05), but this difference was not evidenced in injured lungs. Somewhat lower oxygenation and higher shunt ratio was observed during FCV, nevertheless lung aeration improved and adequate gas exchange was ensured. Therefore, in the absence of major differences in respiratory mechanics and lung volumes, FCV may be considered as an alternative in ventilation therapy of pediatric patients with healthy and injured lungs.

Myocardial injury after major noncardiac surgery: A secondary analysis of a randomized controlled trial

BACKGROUND

Myocardial injury after noncardiac surgery frequently occurs and may influence survival. The aims of this study were to examine the association between myocardial injury after noncardiac surgery and patient and procedural factors as well as its impact on postoperative clinical outcome.

METHODS

A retrospective analysis was conducted from data collected in adults enrolled in a randomized trial in elective major open abdominal surgery. Preoperative patient characteristics, intraoperative hemodynamic changes, and postoperative adverse events were analyzed, and Kaplan-Meier curves were built for postoperative survival probability. After adjustment for baseline patient and procedural characteristics, the effect of myocardial injury after noncardiac surgery on postoperative outcomes was analyzed in a propensity score matched cohort.

RESULTS

Among 394 patients, myocardial injury after noncardiac surgery was reported in 109 (27.7%) and was associated with a higher cardiovascular risk profile, prolonged surgery (333 ± 111 min vs 295 ± 134 min, P = .010), greater need for transfusions (41.3% vs 19.3%, P < .001), higher incidence of major adverse cardiac events (22.9% vs 6.7%, P < .001), pulmonary complications (31.2% vs 17.9%, P = .004) , acute kidney injury (30.3% vs 18.2%, P = .009), and systemic inflammatory syndrome (28.4% vs 13.0%, P < .001). After propensity score matching, the operative time and the need for blood transfusion remained higher among myocardial injury after noncardiac surgery patients who experienced more frequent major adverse cardiac events and acute kidney injury. In both the entire and matched cohorts, survival up to 30 months after surgery was determined mainly by the presence of cancer.

CONCLUSION

The burden of cardiovascular disease and operative stress surgery is predictive of myocardial injury after noncardiac surgery and, in turn, with a higher incidence of cardiac adverse events, whereas the presence of cancer is associated with poor survival in patients undergoing major open abdominal surgery. Further studies are needed to determine whether myocardial injury after noncardiac surgery can be prevented by better control of the patient's cardiovascular condition and implementation of less invasive of surgical procedures.

Goal-directed hemodynamic therapy versus restrictive normovolemic therapy in major open abdominal surgery: A randomized controlled trial

BACKGROUND

The aim of this study was to compare the occurrence of postoperative complications in patients undergoing elective open abdominal surgery and receiving intraoperative goal-directed hemodynamic therapy or restrictive normovolemic therapy.

METHODS

A total of 401 patients were randomized in the goal-directed hemodynamic therapy or restrictive normovolemic therapy groups. A cardiac output monitor was used in all goal-directed hemodynamic therapy patients and was left at the discretion of anesthetists in charge of patients in the restrictive normovolemic therapy group. The primary outcome was a composite morbidity endpoint (30-day mortality and complications grade 2-4 according to Dindo-Clavien classification). Secondary outcomes were the hospital duration of stay, the incidence of pulmonary, cardiovascular, and renal complications up to 30 days after surgery, and midterm survival.

RESULTS

Intraoperatively, the goal-directed hemodynamic therapy group received higher intravenous fluid volumes (mean of 10.8 mL/kg/h and standard deviation of 4.0) compared with the restrictive normovolemic therapy group (mean of 7.2 mL/kg/h and standard deviation of 2.0; P < .001). On the first postoperative day, similar fluid volumes were infused in the 2 groups. The primary outcome occurred in 57.7% of goal-directed hemodynamic therapy and 53.0% of restrictive normovolemic therapy (relative risk, 1.09 [95% confidence interval, 0.91-1.30]), and there was no significant difference between groups for any secondary outcomes.

CONCLUSION

Among patients undergoing major open abdominal surgery, the goal-directed hemodynamic therapy and the restrictive normovolemic therapy were associated with similar incidence of moderate-to-severe postoperative complications and hospital resource use.

Improved Exercise Tolerance, Oxygen Delivery, and Oxygen Utilization After Transcatheter Aortic Valve Implantation for Severe Aortic Stenosis

Background

Transcatheter aortic valve implantation (TAVI) represents an effective therapeutic procedure, particularly in patients with severe aortic stenosis. We hypothesized that the decreased afterload induced by TAVI would improve exercise capacity by enhancing oxygen uptake in working muscles.

Methods

A standardized exercise test was performed in patients with severe aortic stenosis the day before TAVI and within 5 days thereafter. The main study endpoint was the workload achieved during a 5-minute standardized exercise test. Using electrical cardiometry and near-infrared spectroscopy, we explored and compared the changes in cardiac index (CI), as well as muscular and cerebral tissue oximetry, during the 2 exercise tests.

Results

Thirty patients completed the study protocol. Compared with the pre-TAVI period, patients achieved a higher median workload after TAVI (316 Joules [interquartile range {IQR}: 169–494] vs 190 Joules [IQR: 131–301], P = 0.002). Baseline CI increased from 2.5 l/min per m² (IQR: 2.1–2.9) to 2.9 l/min per m² (IQR: 2.5–3.2; P = 0.009), whereas CI at the end of the exercise test increased from 4.5 l/min per m² (IQR: 3.4–5.3) to 4.7 l/min per m² (3.4–6.4; P = 0.019). At the end of the exercise test, cerebral tissue oximetry increased from 70% (IQR: 65–72) to 74% (IQR: 66–78), and muscle tissue oximetry increased from 62% (IQR: 58–65) to 71% (65–74; P = 0.046 and P < 0.001, respectively).

Conclusions

Early improvement of exercise capacity after TAVI is associated with increased CI and better oxygen utilization in the brain and skeletal muscles.

Accountability, research transparency and data reporting

More than one published paper are often derived from analyzing the same cohort of individuals to make full use of the collected information. Preplanned study outcomes are generally mentioned in open databases while exhaustive information on methodological aspects are provided in submitted articles.

Glucose-insulin-potassium improves left ventricular performances after aortic valve replacement: a secondary analysis of a randomized controlled trial

Background

Patients with left ventricular (LV) hypertrophy may suffer ischemia-reperfusion injuries at the time of cardiac surgery with impairment in left ventricular function. Using transesophageal echocardiography (TEE), we evaluated the impact of glucose-insulin potassium (GIK) on LV performances in patients undergoing valve replacement for aortic stenosis.

Methods

In this secondary analysis of a double-blind randomized trial, moderate-to-high risk patients were assigned to receive GIK (20 IU insulin with 10 mEq KCL in 50 ml glucose 40%) or saline over 60 min upon anesthetic induction. The primary outcomes were the early changes in 2-and 3-dimensional left ventricular ejection fraction (2D and 3D-LVEF), peak global longitudinal strain (PGLS) and transmitral flow propagation velocity (Vp).

Results

At the end of GIK infusion, LV-FAC and 2D- and 3D-LVEF were unchanged whereas Vp (mean difference [MD + 7.9%, 95% confidence interval [CI] 3.2 to 12.5%; P <  0.001) increased compared with baseline values. After Placebo infusion, there was a decrease in LV-FAC (MD -2.9%, 95%CI − 4.8 to − 1.0%), 2D-LVEF (MD -2.0%, 95%CI − 2.8 to − 1.3%, 3D-LVEF (MD -3.0%, 95%CI − 4.0 to − 2.0%) and Vp (MD − 4.5 cm/s, 95%CI − 5.6 to − 3.3 cm/s).

After cardiopulmonary bypass, GIK pretreatment was associated with preserved 2D and 3D-LVEF (+ 0.4%, 95% 95%CI − 0.8 to 1.7% and + 0.4%, 95%CI − 1.3 to 2.0%), and PGLS (− 0.9, 95%CI − 1.6 to − 0.2) as well as higher Vp (+ 5.1 cm/s, 95%CI 2.9 to 7.3), compared with baseline. In contrast, in the Placebo group, 2D-LVEF (− 2.2%, 95%CI − 3.4 to − 1.0), 3D-LVEF (− 6.0%, 95%CI − 7.8 to − 4.2), and Vp (− 7.6 cm/s, 95%CI − 9.4 to − 5.9), all decreased after bypass.

Conclusions

Administration of GIK before aortic cross-clamping resulted in better preservation of systolic and diastolic ventricular function in patients with LV hypertrophy undergoing aortic valve replacement.

Trial registration

ClinicalTrials.gov: NCT00788242, registered on November 10, 2008.

Myocardial Protection by Glucose-Insulin-Potassium in Moderate- to High-Risk Patients Undergoing Elective On-Pump Cardiac Surgery: A Randomized Controlled Trial

BACKGROUND

Low cardiac output syndrome is a main cause of death after cardiac surgery. We sought to assess the impact of glucose-insulin-potassium (GIK) to enhance myocardial protection in moderate- to high-risk patients undergoing on-pump heart surgery.

METHODS

A randomized controlled trial was performed in adult patients (Bernstein-Parsonnet score >7) scheduled for elective aortic valve replacement and/or coronary artery bypass surgery. Patients were randomized to GIK (20 IU of insulin, 10 mEq of potassium chloride in 50 mL of glucose 40%) or saline infusion given over 60 minutes on anesthetic induction. The primary end point was postcardiotomy ventricular dysfunction (PCVD), defined as new/worsening left ventricular dysfunction requiring inotropic support (≥120 minutes). Secondary end points were the intraoperative changes in left ventricular function as assessed by transoesophageal echocardiography, postoperative troponin levels, cardiovascular and respiratory complications, and intensive care unit and hospital length of stay.

RESULTS

From 224 randomized patients, 222 were analyzed (112 and 110 in the placebo and GIK groups, respectively). GIK pretreatment was associated with a reduced occurrence of PCVD (risk ratio [RR], 0.41; 95% confidence interval [CI], 0.25-0.66). In GIK-treated patients, the left systolic ventricular function was better preserved after weaning from bypass, plasma troponin levels were lower on the first postoperative day (2.9 ng·mL(-) [interquartile range {IQR}, 1.5-6.6] vs 4.3 ng·mL(-) [IQR, 2.4-8.2]), and cardiovascular (RR, 0.69; 95% CI, 0.50-0.89) and respiratory complications (RR, 0.5; 95% CI, 0.38-0.74) were reduced, along with a shorter length of stay in intensive care unit (3 days [IQR, 2-4] vs 3.5 days [IQR, 2-7]) and in hospital (14 days [IQR, 11-18.5] vs 16 days [IQR, 12.5-23.5]), compared with placebo-treated patients.

CONCLUSIONS

GIK pretreatment was shown to attenuate PCVD and to improve clinical outcome in moderate- to high-risk patients undergoing on-pump cardiac surgery.

A Case of Persistence of Normal Tissue Oxygenation Monitored by Near-Infrared Spectroscopy (NIRS) Values Despite Prolonged Perioperative Cardiac Arrest

Patient: Male, 65

Final Diagnosis: Aortic dissection

Symptoms: Hemiplegia • hypotension

Medication:—

Clinical Procedure: Emergent surgery

Specialty: Surgery

Patient and procedural features predicting early and mid-term outcome after radical surgery for non-small cell lung cancer

Background

Postoperative cardiovascular and pulmonary complications (PCVCs and PPCs) are frequent and result in prolonged hospital stay. The aim of this study was to update the risk factors associated with major complications and survival after lung cancer surgery.

Methods

This is a post-hoc analysis of a randomized controlled trial that was designed to assess the benefits of preoperative physical training. After enrollment, clinical, biological and functional data as well as intraoperative details were collected. In-hospital PCVCs and PPCs were recorded and survival data were adjudicated up to 4 years after surgery.

Results

Data from 151 patients were analyzed. Thirty-day mortality rate was 2.6% and the incidence of PCVCs and PPCs was 15% and 33%, respectively. Stepwise logistic regression analysis showed that, PCVCs were mainly related to elevated plasma levels of brain natriuretic peptides [odds ratios (ORs) =6.0; 95% confidence interval (CI), 1.3-27.3] and performance of a pneumonectomy (OR =9.6; 95% CI, 2.9-31.5) whereas PPCs were associated with the presence of COPD (OR =5.9; 95% CI, 2.4-14.8), current smoking (OR =2.6; 95% CI, 1.1-6.5) and the need for blood transfusion (OR =5.2; 95% CI, 1.2-23.3). Preoperative physical training was a protective factor regarding PPCs (OR =0.13; 95% CI, 0.05-0.34). Cox proportional hazards regression analysis showed that ventilatory inefficiency during exercise (expressed by a ratio >40 of ventilation to carbon dioxide elimination), coronary artery disease, elevated plasma levels of brain natriuretic peptides and the occurrence of PPCs were all predictive of poor survival after surgery.

Conclusions

Besides smoking and the extent of lung resection, preexisting cardiopulmonary disease as evidence by elevated levels of brain natriuretic peptides and inefficient ventilation are associated with poor clinical outcome after lung cancer surgery.

Risk factors of postcardiotomy ventricular dysfunction in moderate-to-high risk patients undergoing open-heart surgery

Introduction:

Ventricular dysfunction requiring inotropic support frequently occurs after cardiac surgery, and the associated low cardiac output syndrome largely contributes to postoperative death. We aimed to study the incidence and potential risk factors of postcardiotomy ventricular dysfunction (PCVD) in moderate-to-high risk patients scheduled for open-heart surgery.

Methods:

Over a 5-year period, we prospectively enrolled 295 consecutive patients undergoing valve replacement for severe aortic stenosis or coronary artery bypass surgery who presented with Bernstein-Parsonnet scores >7. The primary outcome was the occurrence of PCVD as defined by the need for sustained inotropic drug support and by transesophageal echography. The secondary outcomes included in-hospital mortality and the incidence of any major adverse events as well as Intensive Care Unit (ICU) and hospital length of stay.

Results:

The incidence of PCVD was 28.4%. Patients with PCVD experienced higher in-hospital mortality (12.6% vs. 0.6% in patients without PCVD) with a higher incidence of cardiopulmonary and renal complications as well as a prolonged stay in ICU (median + 2 days). Myocardial infarct occurred more frequently in patients with PCVD than in those without PCVD (19 [30.2%] vs. 12 [7.6%]). By logistic regression analysis, we identified four independent predictors of PCVD: left ventricular ejection fraction <40% (odds ratio [OR] = 6.36; 95% confidence interval [CI], 2.59–15.60), age older than 75 years (OR = 3.35; 95% CI, 1.64–6.81), prolonged aortic clamping time (OR = 3.72; 95% CI, 1.66–8.36), and perioperative bleeding (OR = 2.33; 95% CI, 1.01–5.41). The infusion of glucose-insulin-potassium was associated with lower risk of PCVD (OR = 0.14; 95% CI, 0.06–0.33).

Conclusions:

This cohort study indicates that age, preoperative ventricular function, myocardial ischemic time, and perioperative bleeding are predictors of PCVD which is associated with poor clinical outcome.

Assessment of Haemostasis in patients undergoing emergent neurosurgery by rotational Elastometry and standard coagulation tests: a prospective observational study

BACKGROUND

Rotational elastometry (ROTEM) has been shown useful to monitor coagulation in trauma patients and in major elective surgery. In this study, we aimed to evaluate the utility of ROTEM to identify hemostatic disturbances and to predict the need for transfusion, compared with standard coagulation tests (SCTs) in patients undergoing emergent neurosurgery.

METHODS

Over a four-year period, adult patients who met criteria for emergent neurosurgery lasting more than 90 min were included in the study. Blood was collected preoperatively and analyzed with SCTs (international normalized ratio [INR], fibrinogen concentration, prothrombin time [PT or Quick], partial thromboplastine time [PTT], fibrinogen concentration and platelet count), and ROTEM assays. Correlations between SCTs and ROTEM parameters as well as receiver operating characteristic curves were performed to detect a coagulopathic pattern based on standard criteria and the need for transfusing at least 3 units of packed red blood cells (PRBCs).

RESULTS

In a cohort of 92 patients, 39 (42%) required ≥3 PRBCs and a coagulopathic pattern was identified in 32 patients based on SCTs and in 19 based on ROTEM. There was a strong correlation between PTT and INTEM coagulation time (R = 0.76) as well as between fibrinogen concentrations and FIBTEM maximal clot firmess (R = 0.70). The need for transfusion (≥ 3 PRBCs) was best predicted by the maximal clot firmess of EXTEM and FIBTEM (AUC of 0.72 and 0.71, respectively) and by fibrinogen concentration (AUC of 0.70).

CONCLUSIONS

In patients undergoing emergent neurosurgery, ROTEM analysis provides valid markers of early coagulopathy and predictors of blood transfusion requirements.

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.

Subtotal Parathyroidectomy Under Indocyanine Green Angiography

Introduction: Subtotal parathyroid resection is indicated when secondary or tertiary hyperparathyroidism (HPT) develops and may be indicated also in patients with primary HPT and multiglandular disease. Three different surgical procedures are used to treat diffuse parathyroid hyperplasia: total parathyroidectomy with or without autotransplantation, and subtotal parathyroidectomy. One of the main complications is transient or persistent hypoparathyroidism. In this video, we show our technique of subtotal parathyroidectomy using a fluorescent dye (indocyanine green [ICG]) to check for the vascularization of the parathyroid remnant, to avoid definitive postoperative hypoparathyroidism.

Methods: We present a 64-year-old man with end-stage chronic kidney disease dialyzed since 2008. His parathyroid hormone (PTH) level was 106 pmol/L, corrected calcium level was 2.29 mmol/L and phosphate 1.63 mmol/L under maximal medical treatment, and he had significant bone disease. A subtotal parathyroidectomy was scheduled. After reclining pre-thyroid muscles, we medialized the right thyroid lobe to expose the right parathyroid glands. The superior one was a good candidate to be preserved partially because it looked hyperplastic, but without a macroscopic nodule and was the smallest of the four parathyroid glands. The inferior one was located deep in the mediastinum, in the thymus, and was therefore not suitable for subtotal resection. The procedure was the same for the left side. The inferior parathyroid gland harbored nodular hyperplasia and, therefore, was not very suitable for partial resection, but the superior one looked as a good candidate for subtotal resection too. We started reducing the volume of the parathyroid glands with clips, preserving carefully each parathyroid's vascular pedicle. Then, we intravenously injected 3.5 mL of indocyanine green solution to check the perfusion of the parathyroid remnant, using a fluorescent imaging camera (PINPOINT camera; Novadaq, Mississauga, ON, Canada). The perfusion can be seen as green or white, depending on the selected image mode. We finally chose the right superior parathyroid gland and resected the gland outside of the clips. The other glands have finally been entirely removed.

Results: The postoperative course was uneventful except for hypocalcemia needing intravenous calcium for 48 hours. On the first postoperative day, corrected calcium level was 1.93 mmol/L and PTH level was 8 pmol/L. The two inferior parathyroid glands showed nodular hyperplasia at pathologic examination and the two superior glands showed diffuse hyperplasia without nodules.

Conclusion: With this new procedure, subtotal parathyroidectomy under ICG angiography, we can check for the good vascularization of the parathyroid remnant before resecting the other parathyroid glands. Therefore, we can intraoperatively guarantee the absence of definitive hypoparathyroidism. This technique is safe, reproducible, and its easy use makes it the procedure of choice in these situations, when the device is available.

No competing financial interests exist.

Runtime of video: 6 mins 33 secs

Impact of early haemodynamic goal-directed therapy in patients undergoing emergency surgery: an open prospective, randomised trial

Haemodynamic goal-directed therapies (GDT) may improve outcome following elective major surgery. So far, few data exist regarding haemodynamic optimization during emergency surgery. In this randomized, controlled trial, 50 surgical patients with hypovolemic or septic conditions were enrolled and we compared two algorithms of GDTs based either on conventional parameters and pressure pulse variation (control group) or on cardiac index, global end-diastolic volume index and stroke volume variation as derived from the PiCCO monitoring system (optimized group). Postoperative outcome was estimated by a composite index including major complications and by the Sequential Organ Failure Assessment (SOFA) Score within the first 3 days after surgery (POD1, POD2 and POD3). Data from 43 patients were analyzed (control group, N = 23; optimized group, N = 20). Similar amounts of fluid were given in the two groups. Intraoperatively, dobutamine was given in 45 % optimized patients but in no control patients. Major complications occurred more frequently in the optimized group [19 (95 %) versus 10 (40 %) in the control group, P < 0.001]. Likewise, SOFA scores were higher in the optimized group on POD1 (10.2 ± 2.5 versus 6.6 ± 2.2 in the control group, P = 0.001), POD2 (8.4 ± 2.6 vs 5.0 ± 2.4 in the control group, P = 0.002) and POD 3 (5.2 ± 3.6 and 2.2 ± 1.3 in the control group, P = 0.01). There was no significant difference in hospital mortality (13 % in the control group and 25 % in the optimized group). Haemodynamic optimization based on volumetric and flow PiCCO-derived parameters was associated with a less favorable postoperative outcome compared with a conventional GDT protocol during emergency surgery.

Impact of anesthesia technique on the incidence of major complications after open aortic abdominal surgery: a cohort study

STUDY OBJECTIVE

To determine the risk factors of perioperative complications and the impact of intrathecal morphine (ITM) in major vascular surgery.

DESIGN

Retrospective analysis of a prospective cohort.

SETTINGS

Operating room, intensive care unit, and Postanesthesia Care Unit of a university hospital.

MEASUREMENTS

Data from 595 consecutive patients who underwent open abdominal aortic surgery between January 1997 and December 2011 were reviewed. Data were stratified into three groups based on the analgesia technique delivered: systemic analgesia (Goup SA), thoracic epidural analgesia (Group TEA), and intrathecal morphine (Group ITM). Preoperative patient characteristics, perioperative anesthetic and medical interventions, and major nonsurgical complications were recorded.

MAIN RESULTS

Patients managed with ITM (n=248) and those given thoracic epidural analgesia (n=70) required lower doses of intravenous (IV) sufentanil intraoperatively and were extubated sooner than those who received systemic analgesia (n=270). Total inhospital mortality was 2.9%, and 24.4% of patients experienced at least one major complication during their hospital stay. Intrathecal morphine was associated with a lower risk of postoperative morbidity (OR 0.51, 95% CI 0.28 - 0.89), particularly pulmonary complications (OR 0.54, 95% CI 0.31 - 0.93) and renal dysfunction (OR 0.52, 95% CI 0.29 - 0.97). Other predictors of nonsurgical complications were ASA physical status 3 and 4 (OR 1.94, 95% CI 1.07 - 3.52), preoperative renal dysfunction (OR 1.61, 95% CI 1.01 - 2.58), prolonged surgical time (OR 1.78, 95% CI 1.16 - 2.78), and the need for blood transfusion (OR 1.77, 95% CI 1.05 - 2.99).

CONCLUSIONS

This single-center study showed a decreased risk of major nonsurgical complications in patients who received neuraxial analgesia after abdominal aortic surgery.

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.

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.

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

INTRODUCTION

Left 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.

METHODS

Perioperative data were prospectively collected in 108 surgical candidates with an expected operative mortality >or=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).

RESULTS

Doppler-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).

CONCLUSIONS

This study provides the first evidence that, besides advanced age and prolonged myocardial ischemic time, LV diastolic dysfunction characterized by Vp <or= 40 cm/sec identifies patients who will require cardiovascular support following valve replacement for aortic stenosis.

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

Introduction

In 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.

Methods

We 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).

Results

Baseline 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).

Conclusions

Implementing 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.

Effects of methylene blue on propofol requirement during anaesthesia induction and surgery

Delayed emergence from anaesthesia and neurological disturbances have been reported in patients undergoing parathyroidectomy who received methylene blue (MB) pre-operatively. We hypothesised that MB would decrease propofol requirements. The Bispectral index (BIS) and a target-controlled infusion of propofol were used in two groups of 11 matched patients. Patients in one group were pretreated with MB. During induction, clinical sedation scores and BIS values were significantly lower at the predicted effect-site propofol concentration of 2 microg x ml(-1) in the MB compared with the control group. Intra-operatively, although similar BIS values were achieved in the two groups, patients pretreated with MB required a mean 50% lower dose of propofol compared with controls. In view of these findings, care should be taken to ensure an adequate depth of anaesthesia by titrating the administration of anaesthetic agents whenever MB is infused peri-operatively.

Cardioprotective effects of acute normovolemic hemodilution in patients with severe aortic stenosis undergoing valve replacement

BACKGROUND

After acute normovolemic hemodilution (ANH), improvement of the rheologic conditions may contribute to optimize tissue oxygen delivery and attenuate ischemia-reperfusion injuries. It was hypothesized that ANH would confer additional cardioprotection in patients with ventricular hypertrophy undergoing open heart surgery.

STUDY DESIGN AND METHODS

This study was a randomized controlled trial. Forty patients scheduled for elective aortic valve replacement were randomly assigned to a control group (standard care) or an ANH group (target hematocrit level of 28%). All patients were managed with standard myocardial preservation techniques (cold blood cardioplegia, anesthetic preconditioning). The outcome measures included the release of myocardial enzymes, perioperative hemodynamic changes, the need for pharmacologic cardiovascular support, and cardiac complications.

RESULTS

In the ANH group, the postoperative release of troponin I (mean peak plasma concentrations, 1.7 ng/mL; 95% confidence interval, 1.4-2.1 ng/mL) and myocardial fraction of creatine kinase (22 U/L; range, 18-24 U/L) was significantly lower than in the control group (3.6 [range, 3.0-4.2] ng/mL and 45 [range, 39-51] U/L, respectively). In addition, requirement for inotropic support was significantly lower and fewer hemodiluted patients presented adverse cardiac events. After ANH, there was a significant decrease in heart rate (-11 +/- 6%) and rate-pressure product (-16 +/- 8%) until the aortic cross-clamping time and, at the end of surgery, the circulating levels of erythropoietin (EPO) were higher than in control patients (13.6 +/- 4.2 mUI/mL vs. 7.3 +/- 2.4 mUI/mL; p < 0.05).

CONCLUSIONS

Besides conventional cardiac preservation techniques, preoperative ANH further attenuates myocardial injuries. Optimization of preischemic myocardial oxygen delivery and/or consumption and the postconditioning effects of endogenous EPO are potential mechanisms for ANH-induced cardioprotection.

Perioperative medical management of patients with COPD

Chronic obstructive pulmonary disease (COPD) and heart diseases are considered independent risk factors for mortality and major cardiopulmonary complications after surgery. Coronary artery disease, heart failure and COPD share common risk factors and are often encountered,--isolated or combined--, in many surgical candidates. Perioperative optimization of these high-risk patients deserves a thorough understanding of the patient cardiopulmonary diseases as well as the respiratory consequences of surgery and anesthesia. In contrast with cardiac risk stratification where the extent of heart disease largely influences postoperative cardiac outcome, surgical-related factors (ie, upper abdominal and intra-thoracic procedures, duration of anesthesia, presence of a nasogastric tube) largely dominate patient's comorbidities as risk factors for postoperative pulmonary complications. Although most COPD patients tolerate tracheal intubation under "smooth" anesthetic induction without serious adverse effects, regional anesthetic blockade and application of laryngeal masks or non-invasive positive pressure ventilation should be considered whenever possible, in order to provide optimal pain control and to prevent upper airway injuries as well as lung baro-volotrauma. Minimally-invasive procedures and modern multimodal analgesic regimen are helpful to minimize the surgical stress response, to speed up the physiological recovery process and to shorten the hospital stay. Reflex-induced bronchoconstriction and hyperdynamic inflation during mechanical ventilation could be prevented by using bronchodilating volatile anesthetics and adjusting the ventilatory settings with long expiration times. Intraoperatively, the depth of anesthesia, the circulatory volume and neuromuscular blockade should be assessed with modem physiological monitoring tools to titrate the administration of anesthetic agents, fluids and myorelaxant drugs. The recovery of postoperative lung volume can be facilitated by patient's education and empowerment, lung recruitment maneuvers, non-invasive pressure support ventilation and early ambulation.

Incidence, risk factors and prognosis of changes in serum creatinine early after aortic abdominal surgery

OBJECTIVE

To determine the incidence, risk factors, and prognostic implications of serum creatinine changes following major vascular surgery.

DESIGN

Observational study.

SETTINGS

University hospital.

PATIENTS

Cohort of 599 consecutive patients undergoing elective abdominal aortic surgery.

INTERVENTIONS

Review of prospectively collected data from 1993 to 2004.

MEASUREMENTS AND RESULTS

The receiver-operator characteristic (ROC) curve analysis was used to detect the best threshold for postoperative elevation in serum creatinine (Delta Creat) in relation to major complications. A cut-off value of +0.5 mg/dl was selected to define renal dysfunction (RD(0.5) group, n=91; no RD(0.5), n=508) that was associated with higher mortality (7.7% in RD(0.5) group vs 1.4% in no RD(0.5) group, P<0.05), rate of admission to the ICU (34% vs 13%, P<0.05), and incidence of cardiovascular (9% vs 4%, P<0.05), respiratory (21% vs 7%, P<0.05), surgical (24% vs 10%, P<0.05), and septic complications (9% vs 3%, P<0.05). After multivariate analysis with logistic regression, renal dysfunction was independently related to low preoperative creatinine clearance [<40 ml/min; odds ratio (OR) 1.5, 95% confidence interval (CI) 1.1-3.9], prolonged renal ischemic time (>40 min; OR, 3.8, 95% CI, 1.9-7.2), blood transfusion (>5 units; OR, 1.9, 95% CI 1.2-6.1), and rhabdomyolysis (OR, 3.6, 95% CI 1.7-7.9).

CONCLUSIONS

Postoperative RD(0.5) (Delta Creat >0.5 mg/dl) occurs in 15% of vascular patients and carries a bad prognosis. Preoperative renal insufficiency and factors related to the complexity of surgery are the main predictors of renal dysfunction.

Cardioprotective Effects of Acute Normovolemic Hemodilution in Patients Undergoing Coronary Artery bypass Surgery

STUDY OBJECTIVES

We hypothesized that lowering blood viscosity with acute normovolemic hemodilution (ANH) would confer additional cardioprotection in patients undergoing coronary artery bypass surgery (CABG) with aortic cross-clamping.

DESIGN

In a prospective, randomized controlled trial, we studied the efficacy of ANH in anesthetized patients prior to cardiopulmonary bypass for the prevention of myocardial injuries.

SETTING

Cardiac surgical center in a university hospital.

PATIENTS AND METHODS

Patients scheduled to undergo elective CABG entered the study protocol and were randomly allocated to one of two groups: ANH (n = 43 patients) or standard care management (n = 41 patients). In the ANH group, the whole-blood/colloid exchange was aimed to achieve a hematocrit value of 28%. All patients were managed with standard myocardial preservation techniques including cold-blood cardioplegia and anesthetic preconditioning. The outcome measures included the release of myocardial enzymes (plasma troponin I and creatinine phosphokinase), perioperative hemodynamic changes, need for pharmacologic cardiovascular support, and cardiac complications.

RESULTS

In the hemodilution group, the postoperative release of troponin I (mean peak plasma concentration, 1.4 ng/mL; 95% confidence interval, 1.0 to 1.8) and myocardial fraction of creatine kinase (mean, 29 U/L; 95% confidence interval, 23 to 35) were significantly lower than in the control group (mean, 3.8 ng/mL; 95% confidence interval, 3.2 to 4.5; and 71 U/L; 95% confidence interval, 53 to 89). Requirement for inotropic support was significantly lower in the protocol patients (7 of 41 patients vs 15 of 39 patients), and fewer patients presented with either atrial fibrillation, atrioventricular conduction blockade, or combined disorders (12 of 41 patients vs 26 of 39 patients, p < 0.05).

CONCLUSIONS

In addition to conventional myocardial preservation techniques, preoperative ANH achieved further cardiac protection in patients undergoing on-pump myocardial revascularization.