Postpneumonectomy pulmonary edema. A retrospective analysis of incidence and possible risk factors

Development and validation of a nomogram to pediatric postoperative pulmonary complications following thoracic surgery

BACKGROUND

Since the respiratory anatomy and physiology of children differ from those of adults, they are more susceptible to postoperative pulmonary complications after thoracic surgery that requires one-lung ventilation. Hypothesizing that the incidence of postoperative pulmonary complications could be predicted using easily accessible perioperative variables, we aimed to develop a nomogram specifically for children receiving thoracic surgery with one-lung ventilation.

METHODS

A total of 361 children undergoing thoracic surgery with one-lung ventilation were randomly assigned to two groups: a training cohort (80%) and a validation cohort (20%). The training cohort was utilized to develop a nomogram, whereas the validation cohort was used to assess its performance. The outcome of this study was the incidence of postoperative pulmonary complications. Univariate analysis and the least absolute shrinkage and selection operator regression model were applied to select the most relevant prognostic predictors. Multivariable logistic regression was used to develop a nomogram based on the selected prediction factors. Internal validation was conducted to evaluate its performance. The C-index and calibration plots were used to assess its discriminative ability and calibration.

RESULTS

Among the included patients, 109 (30.2%) presented postoperative pulmonary complications. Four predictive factors were ultimately selected to develop the nomogram. They were preoperative neutrophil-to-lymphocyte ratio, intraoperative ventilation mode, maximum peak airway pressure and minimum oxygenation index during one-lung ventilation. By incorporating these factors, the nomogram demonstrated strong C-indices of 0.909 (95% confidence interval (CI) [0.809-0.82]) and 0.871 (95% CI [0.795-0.945]) in the training and validation cohorts, respectively, along with well-matched calibration curves.

CONCLUSION

The nomogram, based on four objective and easily assessed factors, demonstrates excellent predictive performance for pediatric postoperative pulmonary complications after one-lung ventilation, enabling early risk assessment and targeted interventions to improve patient outcomes.

TRIAL REGISTRATION

This study is registered at the Chinese Clinical Trial Registry (Registration number: ChiCTR2300072042, Date of Registration: 1/6/2023).

Effect of spine frame on the changes in respiratory dynamics in prone patients under general anaesthesia- a prospective, observational study

Background and Aims

The prone position is one of the common surgical positions used in clinical practice. Manoeuvring patients from supine to a prone position can impact respiratory dynamics and result in haemodynamic variations.

Methods

This study included 64 patients and was conducted after obtaining approval from the ethics committee and registration of the trial. The primary objective was to evaluate the changes in peak inspiratory pressure (PIP), plateau pressure (Pplat) and mean airway pressure (MAP) in patients undergoing surgery under general anaesthesia in the prone position with (Group S) and without (Group P) spine frame. The secondary objective was to evaluate and compare the variations in heart rate and blood pressure.

Results

On turning the patient prone, there was statistically significant increase in median PIP (Group S 4 cmH2O vs. Group P 0.5 cmH2O, P < 0.001), Pplat (Group S 3.5 cmH2O vs. Group P 1 cmH2O, P = 0.004) and dynamic compliance (Group S -5.513 vs. Group P -2.78, P < 0.004).

Conclusions

Our study found that prone positioning with a spine frame led to a significantly greater increase in airway pressures and a decrease in dynamic compliance when compared to patients positioned prone without the spine frame.

Normalized Pulmonary Artery Diameter Predicts Occurrence of Postpneumonectomy Respiratory Failure, ARDS, and Mortality

Hypothesizing that pulmonary artery diameter is a marker of subclinical pulmonary hypertension, we assessed its impact on postoperative outcome in patients requiring pneumonectomy. Morphometric, clinical, and laboratory data were retrospectively retrieved from files of 294 consecutive patients treated by pneumonectomy for malignancy (289 NSCLC). Pulmonary artery was measured at bifurcation level on CT scan and normalized by body surface area. Median normalized pulmonary artery diameter (cut-off for analyses) was 14 mm/m2. Postoperatively, 46 patients required re-do intubation and 30 had acute respiratory distress syndrome (ARDS). Multivariate analysis showed that Charlson Comorbidity Index >5 (p = 0.0009, OR 3.8 [1.76-8.22]), right side of pneumonectomy (p = 0.013, OR 2.37 [1.20-4.71]), and higher normalized pulmonary artery diameter (p = 0.029, OR 2.16 [1.08-4.33]) were independent predictors of re-do intubation, while Charlson Comorbidity Index >5 (p = 0.018, OR 2.55 [1.17-5.59]) and higher normalized pulmonary artery diameter (p = 0.028, OR = 2.52 [1.10-5.77]) were independently associated with occurrence of ARDS. Post-operative mortality was 8.5%. Higher normalized pulmonary artery diameter, (p = 0.026, OR 3.39[1.15-9.95]), right side of pneumonectomy (p = 0.0074, OR 4.11 [1.46-11.56]), and Charlson Comorbidity Index >5 (p = 0.0011, OR 5.56 [1.99-15.54]) were independent predictors of postoperative death. We conclude that pre-operative normalized pulmonary artery diameter predicts the risk of re-do intubation, ARDS and mortality in patients undergoing pneumonectomy for cancer.

Balanced Chest Drainage Prevents Post-Pneumonectomy Pulmonary Oedema

BACKGROUND

Pneumonectomy in the adult patient is associated with a mortality of 1-9%. Death is often due to post pneumonectomy pulmonary oedema (PPPO). The use of balanced chest drainage system (BCD) in the setting of post pneumonectomy has been reported to be of benefit in the prevention of PPPO. This study seeks to compare the incidence of PPPO in patients who underwent pneumonectomy and whose empty pleural space was managed either with CRD or BCD.

METHODS

This retrospective observational cohort study involved 98 patients who were operated on by one surgeon at Liverpool Hospital, Sydney, Australia from 1997 to 2019. The patients were divided into two groups according to the era in which they had their pneumonectomy. Group 1 consisted of 18 patients managed with clamp-release drainage between 1997 and 2002. Group 2 consisted of 80 patients managed with balanced chest drainage between 2003 and 2019. The primary outcomes of interest were the development of PPPO and death. Demographic and clinico-pathological variables between the groups were compared including whether the phrenic nerve was sacrificed, volume of infused intraoperative fluid, duration of single lung ventilation, intraoperative tidal volumes, agents of anaesthetic induction and maintenance, mean urine output in the first 4 postoperative hours, institution of a postoperative 1.5 L fluid restriction, total chest drainage, day of chest drain removal, presence of radiological postoperative mediastinal shift, post-pneumonectomy pulmonary oedema and death. Group characteristics were compared using t-test and chi-squared for continuous and categorical variables respectively. Univariate and multivariate analysis was also undertaken using the Firth method of logistic regression for rare occurrences in a stepwise fashion.

RESULTS

Through univariate analysis, balanced chest drainage, postoperative fluid restriction and intraoperative fluid infusion showed significant effect on PPPO. Through multivariate analysis, balanced chest drainage was found to have independent protective value for PPPO and mortality.

CONCLUSION

Compared with clamp-release drainage, balanced chest drainage results in a lower incidence of post-pneumonectomy pulmonary oedema and death.

Application of alveolar recruitment strategy and positive end-expiratory pressure combined with autoflow in the one-lung ventilation during thoracic surgery in obese patients

Background

The present study aims to evaluate the influence of alveolar recruitment strategy (ARS) and positive end-expiratory pressure (PEEP) combined with autoflow on respiratory mechanics, the oxygen index (OI), pulmonary shut [Qs/Qt(%)], and the concentrations of IL-6 and TNF-α in venous blood after surgery in obese patients who experienced thoracic surgery with one-lung ventilation (OLV).

Methods

A total of 36 obese patients with ASAII-III degree, who experienced selective pulmonary lobectomy, were within 36-74 years old, and had a BMI of 30-40 kg/m², were randomly divided into two groups: control group (C group) and protective ventilation group (P group). In the P group, ARS was given once when OLV began. Then, ventilation at 7 mmHg of PEEP and autoflow were given. The P_peak before OLV (T₁), at 30 minutes after OLV (T₂), and at the 5 minutes after two-lung ventilation (TLV) (T₃), and the changes of P_plat and Cdyn were recorded. Then, arteriovenous blood was drawn at T₁, T₂, T₃ and T₄ (6 hours after the operation), blood-gas indicators, including SPO₂, PaCO₂ and PaO₂, were measured, and the value of Qs/Qt(%) was calculated. Afterwards, venous blood was collected at T₁ and T₅ (18 hours after surgery), and the concentrations of IL-6 and TNF-α were detected. The clinical pulmonary infection score (CPIS) was determined at the first day and seventh day after the operation.

Results

In both groups, Cdyn and OI decreased, while P_plat, P_peak and Qs/Qt(%) increased (P<0.05) at T₂, when compared with those at T₁. At T₂ and T₃, P_plat and P_peak decreased (P<0.05) in the P group, when compared with the C group. At T₂, T₃ and T₄, OI increased (P<0.05) in the P group, when compared with the C group. At T₂, T₃ and T₄, PaCO₂ and Qs/Qt(%) decreased in the P group, when compared with the C group. The concentrations of IL-6 and TNF-α decreased in the P group, when compared with the C group.

Conclusions

The ventilation model of ARS and PEEP combined with autoflow can better reduce airway pressure and the production of injurious inflammatory cytokines in blood in obese patients. Furthermore, it can reduce Qs/Qt during and at 6 hours after thoracotomy, improve OI and maintain the acid-base balance of the internal environment, which may be applied in clinical work. This brings new enlightenment and needs to be clarified through further studies.

Patients experiencing early acute respiratory failure have high postoperative mortality after pneumonectomy

OBJECTIVE

Post-pneumonectomy acute respiratory failure leading to invasive mechanical ventilation carries a severe prognosis especially when acute respiratory distress syndrome occurs. The aim of this study was to describe risk factors and outcome of acute respiratory failure.

METHODS

We retrospectively reviewed clinical files of all patients who underwent pneumonectomy in a single center between 2005 and 2015. Risk factors and outcome of acute respiratory failure were assessed in univariate and multivariate analysis.

RESULTS

Among the 543 patients who underwent pneumonectomy in the period of study, 89 (16.4%) needed reintubation within the 30th postoperative day and 60 of these (11% of all pneumonectomies) developed acute respiratory distress syndrome. In multivariate analysis, right-side of pneumonectomy (odds ratio [OR], 2.29; 95% confidence interval [CI], 1.24-4.22), chronic cardiac disease (OR, 2.15; 95% CI, 1.08-4.25), Charlson Comorbidity Index (OR, 1.35; 95% CI, 1.14-1.61), carinal resection (OR, 3.23; 95% CI, 1.26-8.29), and extrapleural pneumonectomy (OR, 8.36; 95% CI, 3.31-21.11) were identified as independent risk factors of reintubation. Thirty-day mortality was 7.7% for all pneumonectomies, 41.6% (37/89) in the invasive ventilation group, and 53.3% (32/60) in patients with acute respiratory distress syndrome. In non-reintubated patients, 30-day mortality was 1.1% (5/454). In reintubated patients, 5-year survival was 27.1% (95% CI, 17.8-41.4).

CONCLUSIONS

Early acute respiratory failure requiring reintubation remains a severe complication of pneumonectomy with a poor outcome.

Protective effects of continuous positive airway pressure on a nonventilated lung during one-lung ventilation: A prospective laboratory study in rats

BACKGROUND

The use of one-lung ventilation (OLV) to facilitate intrathoracic surgery is a cause of lung injury.

OBJECTIVE

We hypothesised that application of continuous positive airway pressure (CPAP) to a nonventilated lung during OLV would prevent alveolar hypoxia and blood flow shift from the nonventilated to the ventilated lung, thereby attenuating lung injury.

DESIGN

Controlled animal study.

SETTINGS

University laboratory.

STUDY PARTICIPANTS

Adult male Sprague-Dawley rats (n = 4 to 8 per group, depending on experiments).

INTERVENTIONS

Rats were alternately assigned to one of two ventilation protocol groups: control and CPAP groups. Rats received 240 min of OLV followed by 240 min of two-lung reventilation (re-TLV). The nonventilated lungs of rats in the control group were collapsed during OLV whereas rats in the CPAP group received CPAP (5 cmH2O with 100% oxygen) to the nonventilated lungs.

MAIN OUTCOME MEASURES

Pulmonary blood flow during OLV was measured by quantification of lung radioactivity after intravenous infusion of indium-labelled macroaggregated albumin. Inflammatory cytokines in the lungs after 240 min of OLV, and after the subsequent 240 min of re-TLV were measured. Additionally, we measured lung wet-to-dry weight ratios after re-TLV. We also measured lung malondialdehyde levels after re-TLV as an indicator of reactive oxygen species produced by reoxygenation.

RESULTS

Application of CPAP attenuated the pulmonary blood flow shift from the nonventilated to the ventilated lung. CPAP decreased the levels of IL-6, CXC chemokine ligand-1 and CC chemokine ligand-2 in both lungs after 240 min of OLV. CPAP also decreased CXC chemokine ligand-1 in the nonventilated lung and CC chemokine ligand-2 in both lungs after re-TLV. Moreover, wet-to-dry weight ratios of both lungs were decreased by application of CPAP. However, lung malondialdehyde concentrations were not affected by CPAP.

CONCLUSIONS

CPAP applied to the nonventilated lung during OLV suppresses blood flow shift and decreases inflammatory cytokines and water content in both lungs. Application of CPAP may attenuate lung injury during and after OLV.

Effects of pressure-controlled and volume-controlled ventilation on respiratory mechanics and systemic stress response during prone position

BACKGROUND

Prone position during general anesthesia for special surgical operations may be related with increased airway pressure, decreased pulmonary and thoracic compliance that may be explained by restriction of chest expansion and compression of abdomen. The optimum ventilation mode for anesthetized patients on prone position was not described and studies comparing volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) during prone position are limited. We hypothesized that PCV instead of VCV during prone position could achieve lower airway pressures and reduce the systemic stress response. In this study, we aimed to compare the effects of PCV and VCV modes during prone position on respiratory mechanics, oxygenation, and hemodynamics, as well as blood cortisol and insulin levels, which has not been investigated before.

METHODS

Fifty-four ASA I-II patients, 18-70 years of age, who underwent percutaneous nephrolithotomy on prone position, were randomly selected to receive either the PCV (Group PC, n = 27) or VCV (Group VC, n = 27) under general anesthesia with sevoflurane and fentanyl. Blood sampling was made for baseline arterial blood gases (ABG), cortisol, insulin, and glucose levels. After anesthesia induction and endotracheal intubation, patients in Group PC were given pressure support to form 8 mL/kg tidal volume and patients in Group VC was maintained at 8 mL/kg tidal volume calculated using predicted body weight. All patients were maintained with 5 cmH₂O PEEP. Respiratory parameters were recorded during supine and prone position. Assessment of ABG and sampling for cortisol, insulin and glucose levels were repeated during surgery and 60 min after extubation.

RESULTS

P-peak and P-plateau levels during supine and prone positions were significantly higher and P-mean and compliance levels during prone position were significantly lower in Group VC when compared with Group PC. Postoperative PaO₂ level was significantly higher in Group PC compared with Group VC. Cortisol levels were increased with surgery in both groups (p < 0.05) and decreased to baseline levels in Group PC while remained high in Group VC in the early postoperative period. Cortisol levels were significantly higher in Group VC during surgery and in the early postoperative period compared with Group PC.

CONCLUSION

When compared with VCV mode, PCV mode is associated with lower P-peak and P-plateau levels during both supine and prone positions, better oxygenation postoperatively, lower blood cortisol levels during surgery in prone position and in the early postoperative period. We concluded that PCV mode might be more appropriate in prone position during anesthesia.

Anesthetic management of robot-assisted thoracoscopic thymectomy

Myasthenia gravis (MG) is a rare disorder involving neuromuscular junction. In conjunction with medical therapy, thymectomy is a known modality of treatment of MG and has shown to increase the probability of remission and overall symptomatic improvement. For minimally invasive thymectomy, video-.assisted thoracoscopic surgery has been the preferred surgical approach till recently. The robotic surgical procedure must necessarily bring new challenges to the anesthesiologists to effectively meet the specific requirements of the technique. At present, there is a paucity of literature regarding the anesthetic concerns of robotic assisted thymectomy, patient in question specifically posed a challenge since different maneuvers and techniques had to be tried to obtain optimum surgical conditions with stable ventilatory and hemodynamic parameters. Concerns of patient positioning and hemodynamic monitoring have also been discussed.

Common Pitfalls in Anesthesia for Noncardiac Thoracic Surgery

Over the past few decades, major surgical procedures involving the thorax have become commonplace at most larger medical facilities. Advances in perioperative care have allowed surgeons to perform increasingly complex procedures. These procedures are being performed on more seriously ill patients who are at increased risk for significant complications. Recent advances should help the anesthesiologist avoid some of the pitfalls in managing these complex patients. Preoperative assessment aids in the identification of patients at highest risk for intraoperative and postoperative events. Particular attention is given to myasthenia gravis, as thymectomy is among the most common surgical procedures that are performed in these patients. Aggressive pain control techniques, including neuraxial opioids and patient-controlled analgesia, where appropriate, not only improve patient comfort but can improve postoperative pulmonary function. Advances in techniques for providing one-lung ventilation allow the anesthesiologist more options to individualize management for each clinical scenario. Careful fluid management may help to minimize the risk of postoperative pulmonary complications. A basic understanding of video-assisted thoracic surgery should help the anesthesiologist provide optimal surgical conditions and perioperative care. Recent advances demand a greater role for the anesthesiologist if the best outcomes are to be achieved in patients undergoing thoracic procedures.

Perioperative lung-protective ventilation strategy reduces postoperative pulmonary complications in patients undergoing thoracic and major abdominal surgery

The occurrence of postoperative pulmonary complications is strongly associated with increased hospital mortality and prolonged postoperative hospital stays. Although protective lung ventilation is commonly used in the intensive care unit, low tidal volume ventilation in the operating room is not a routine strategy. Low tidal volume ventilation, moderate positive end-expiratory pressure, and repeated recruitment maneuvers, particularly for high-risk patients undergoing major abdominal surgery, can reduce postoperative pulmonary complications. Facilitating perioperative bundle care by combining prophylactic and postoperative positive-pressure ventilation with intraoperative lung-protective ventilation may be helpful to reduce postoperative pulmonary complications.

Post-operative pulmonary complications after thoracotomy

Pulmonary complications are a major cause of morbidity and mortality in the post-operative period after thoracotomy. The type of complications and the severity of complications depend on the type of thoracic surgery that has been performed as well as on the patient's pre-operative medical status. Risk stratification can help in predicting the possibility of the post-operative complications. Certain airway complications are more prone to develop with thoracic surgery. Vocal cord injuries, bronchopleural fistulae, pulmonary emboli and post-thoracic surgery non-cardiogenic pulmonary oedema are some of the unique complications that occur in this subset of patients. The major pulmonary complications such as atelectasis, bronchospasm and pneumonia can lead to respiratory failure. This review was compiled after a search for search terms within 'post-operative pulmonary complications after thoracic surgery and thoracotomy' on search engines including PubMed and standard text references on the subject from 2000 to 2015.

Lung Injury After One-Lung Ventilation: A Review of the Pathophysiologic Mechanisms Affecting the Ventilated and the Collapsed Lung

Lung injury is the leading cause of death after thoracic surgery. Initially recognized after pneumonectomy, it has since been described after any period of 1-lung ventilation (OLV), even in the absence of lung resection. Overhydration and high tidal volumes were thought to be responsible at various points; however, it is now recognized that the pathophysiology is more complex and multifactorial. All causative mechanisms known to trigger ventilator-induced lung injury have been described in the OLV setting. The ventilated lung is exposed to high strain secondary to large, nonphysiologic tidal volumes and loss of the normal functional residual capacity. In addition, the ventilated lung experiences oxidative stress, as well as capillary shear stress because of hyperperfusion. Surgical manipulation and/or resection of the collapsed lung may induce lung injury. Re-expansion of the collapsed lung at the conclusion of OLV invariably induces duration-dependent, ischemia-reperfusion injury. Inflammatory cytokines are released in response to localized injury and may promote local and contralateral lung injury. Protective ventilation and volatile anesthesia lessen the degree of injury; however, increases in biochemical and histologic markers of lung injury appear unavoidable. The endothelial glycocalyx may represent a common pathway for lung injury creation during OLV, because it is damaged by most of the recognized lung injurious mechanisms. Experimental therapies to stabilize the endothelial glycocalyx may afford the ability to reduce lung injury in the future. In the interim, protective ventilation with tidal volumes of 4 to 5 mL/kg predicted body weight, positive end-expiratory pressure of 5 to 10 cm H2O, and routine lung recruitment should be used during OLV in an attempt to minimize harmful lung stress and strain. Additional strategies to reduce lung injury include routine volatile anesthesia and efforts to minimize OLV duration and hyperoxia.

Effect of tidal volume on extravascular lung water content during one-lung ventilation for video-assisted thoracoscopic surgery: a randomised, controlled trial

BACKGROUND

The use of low tidal volume during one-lung ventilation (OLV) has been shown to attenuate the incidence of acute lung injury after thoracic surgery.

OBJECTIVE

To test the effect of tidal volume during OLV for video-assisted thoracoscopic surgery on the extravascular lung water content index (EVLWI).

DESIGN

A randomised, double-blind, controlled study.

SETTING

Single university hospital.

PARTICIPANTS

Thirty-nine patients scheduled for elective video-assisted thoracoscopic surgery.

INTERVENTIONS

Patients were randomly assigned to one of three groups (n = 13 per group) to ventilate the dependent lung with a tidal volume of 4, 6 or 8 ml  kg(-1) predicted body weight with I:E ratio of 1:2.5 and PEEP of 5 cm H2O.

MAIN OUTCOME MEASURES

The primary outcomes were perioperative changes in EVLWI and EVLWI to intrathoracic blood volume index (ITBVI) ratio. Secondary outcomes included haemodynamics, oxygenation indices, incidences of postoperative acute lung injury, atelectasis, pneumonia, morbidity and 30-day mortality.

RESULTS

A tidal volume of 4 compared with 6 and 8 ml  kg(-1) after 45 min of OLV resulted in an EVLWI of 4.1 [95% confidence interval (CI) 3.5 to 4.7] compared with 7.7 (95% CI 6.7 to 8.6) and 8.6 (95% CI 7.5 to 9.7) ml  kg(-1), respectively (P < 0.003). EVLWI/ITBVI ratios were 0.57 (95% CI 0.46 to 0.68) compared with 0.90 (95% CI 0.75 to 1.05) and 1.00 (95% CI 0.80 to 1.21), respectively (P < 0.05). The incidences of postoperative acute lung injury, atelectasis, pneumonia, morbidity, hospitalisation and 30-day mortality were similar in the three groups.

CONCLUSION

The use of a tidal volume of 4 ml kg during OLV was associated with less lung water content than with larger tidal volumes of 6 to 8 ml kg(-1), although no patient developed acute lung injury. Further studies are required to address the usefulness of EVLWI as a marker for the development of postoperative acute lung injury after the use of a low tidal volume during OLV in patients undergoing pulmonary resection.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT01762709.

Comparison of pulmonary gas exchange according to intraoperative ventilation modes for mitral valve repair surgery via thoracotomy with one-lung ventilation: a randomized controlled trial

OBJECTIVE

Impaired pulmonary gas exchange after cardiac surgeries with cardiopulmonary bypass (CPB) often occurs, and the selection of mechanical ventilation mode, pressure-controlled ventilation (PCV) or volume-controlled ventilation (VCV), may be important for preventing hypoxia and improving oxygenation. The authors hypothesized that patients with PCV would show better oxygenation, compared with VCV, during one-lung ventilation (OLV) for mitral valve repair surgery (MVP) via thoracotomy.

DESIGN

Randomized controlled trial.

SETTING

University teaching hospital.

PARTICIPANTS

Sixty patients in each group.

INTERVENTIONS

MVP was performed using thoracotomy with OLV by PCV or VCV.

MEASUREMENTS AND MAIN RESULTS

Arterial partial pressure of oxygen (PaO2) and fraction of inspired oxygen (FIO2) were measured before anesthesia induction (T0), at skin incision (T1), after administration of heparin (T2), at 30 minutes after CPB weaning (T3), just before departure from the operating room to the intensive care unit (ICU) (T4), and 1 hour after ICU admission (T5), and PaO2/FIO2 ratio was calculated. Peak inspiratory pressure (PIP) and mean inspiratory pressure (Pmean) were recorded at T1, T2, T3, and T4. No significant difference was noted in the PaO2/FIO2 ratio between the groups at any measured point. PIP in the PCV group at all measured points was lower than that in the VCV group (T1, p<0.001; T2, p<0.001; T3, p<0.001; T4, p=0.025, respectively). Pmean was not different between the two groups at any measured point.

CONCLUSIONS

PCV during OLV in patients undergoing MVP via a thoracotomy with OLV showed lower PIP compared with VCV, but this did not improve pulmonary gas exchange.

Delayed pulmonary arterial hypertension in relation to pulmonary damage score after pneumonectomy under protective ventilation: experimental study

OBJECTIVE

To characterize pulmonary hemodynamic changes in relation to lung injury at 2 time points [48 h (H48) and 168 h (H168)] after pneumonectomy under intraoperative protective ventilation in order to improve postpneumonectomy pulmonary edema (PPE) prevention.

METHOD

Fifteen pigs (25 ± 1.9 kg) were randomly allocated to nonsurgical (control, n = 5) and surgical (H48 and H168) groups. A left pneumonectomy under volume-controlled one-lung ventilation (OLV) (low tidal volume, positive end-expiratory pressure = 4 cm H2O, inspired oxygen fraction = 50%) was performed in surgical animals. Mean pulmonary artery pressure (MPAP) and pulmonary artery occlusion pressure were recorded. Pulmonary vascular resistance (PVR) was calculated. Pulmonary damage score (PDS) and bronchoalveolar albumin level were evaluated. Data were collected after induction (T0), after OLV (T1), after left pneumonectomy (T2), and at H48 or H168 (T3).

RESULTS

Pneumonectomy caused precapillary pulmonary arterial hypertension (PAH) measured at T3 H48 (36.2 ± 3.67 mm Hg). PAH was delayed temporarily (both after OLV and after pneumonectomy) (p < 0.001), and linked with PVR (r = 0.93; p < 0.05). PDS and bronchoalveolar albumin level varied with MPAP (r = 0.76; p < 0.001 and r = 0.55; p < 0.05).

CONCLUSION

Given that PAH is delayed and related to PVR increase, indicating secondary pulmonary vascular bed adaptation limits, pharmacological treatment should focus on a delayed failure in pulmonary capacitance in patients at risk of PPE.

Special article: the endothelial glycocalyx: emerging concepts in pulmonary edema and acute lung injury

The endothelial glycocalyx is a dynamic layer of macromolecules at the luminal surface of vascular endothelium that is involved in fluid homeostasis and regulation. Its role in vascular permeability and edema formation is emerging but is still not well understood. In this special article, we highlight key concepts of endothelial dysfunction with regards to the glycocalyx and provide new insights into the glycocalyx as a mediator of processes central to the development of pulmonary edema and lung injury.

Acute lung injury in thoracic surgery

PURPOSE OF REVIEW

This review will analyze the risk factors of acute lung injury (ALI) in patients undergoing thoracic surgery. Evidence for the occurrence of lung injury following mechanical ventilation and one-lung ventilation (OLV) and the strategies to avoid it will also be discussed.

RECENT FINDINGS

Post-thoracotomy ALI has become one of the leading causes of operative death. The pathogenesis of ALI implicates a multiple-hit sequence of various triggering factors (e.g. preoperative conditions, surgery-induced inflammation, ventilator-induced injury, fluid overload, and transfusion). Conventional ventilation during OLV is performed with high tidal volumes equal to those being used in two-lung ventilation, high FiO(2), and without positive end-expiratory pressure. This practice was originally recommended to improve oxygenation and decrease shunt fraction during OLV. However, a number of recent studies using experimental models or human patients have shown low tidal volumes to be associated with a decrease in inflammatory mediators and a reduction in pulmonary postoperative complications. However, the application of such protective strategies could be harmful if not still properly used.

SUMMARY

The goal of ventilation is to minimize lung trauma by avoiding overdistension and repetitive alveolar collapse, while providing adequate oxygenation. Protective ventilation is not simply synonymous of low tidal volume ventilation, but it also involves positive end-expiratory pressure, lower FiO(2), recruitment maneuvers, and lower ventilatory pressures.

Acute respiratory distress syndrome after pulmonary resection

Postoperative acute respiratory distress syndrome (ARDS) is a recognized complication of pulmonary resection. It is characterized by the acute onset of hypoxemia with radiographic infiltrates consistent with pulmonary edema, without elevations in the pulmonary capillary wedge pressure. Many studies suggest that around 2-5 % of patients develop some degree of lung injury, and the mortality from ARDS following pulmonary resection remains high. ARDS following thoracotomy and lung resection has a miserable prognosis, with overall hospital mortality rates over 25 %. The present review evaluates the evidence available in the literature tracking perioperative mortality and morbidity as well as the pathogenesis and management of ARDS in patients undergoing pulmonary resection.

A randomized comparison of different ventilator strategies during thoracotomy for pulmonary resection

OBJECTIVE

Protective lung ventilation is reported to benefit patients with acute respiratory distress syndrome. It is not known whether protective lung ventilation is also beneficial to patients undergoing single-lung ventilation for elective pulmonary resection.

METHODS

In an institutional review board-approved prospective randomized trial, 34 patients undergoing elective pulmonary resection requiring single-lung ventilation were enrolled. Informed consent was obtained. Patients were randomized to 1 of 2 groups: (1) high tidal volume (Hi-TV) of 10 mL/kg, rate of 7 breaths/min, and zero positive end-expiratory pressure or (2) low tidal volume (Lo-TV) of 5 mL/kg, rate of 14 breaths/min, and 5 cmH2O positive end-expiratory pressure. Ventilator settings were continued during both double- and single-lung ventilation. Pulmonary functions, hemodynamics, and postoperative outcomes were recorded.

RESULTS

Patient demographics, operative characteristics, intraoperative hemodynamics, and postoperative pain and sedation scores were similar between the 2 groups. During most time periods, airway pressures (peak and plateau) were significantly higher in the Hi-TV group; however, plateau pressures remained less than 30 cmH2O at all times for all patients. The Hi-TV group had significantly lower arterial carbon dioxide tension, less arterial carbon dioxide tension-end-tidal carbon dioxide gradient, lower alveolar dead space ratio, and higher dynamic pulmonary compliance. There were no differences in postoperative morbidity and hospital days between the 2 groups, but atelectasis scores on postoperative days 1 and 2 were lower in the Hi-TV group.

CONCLUSIONS

The use of Hi-TV during single-lung ventilation for pulmonary resection resulted in no increase in morbidity and was associated with less hypercarbia, less dead space ventilation, better dynamic compliance, and less postoperative atelectasis.

Does a conservative fluid management strategy in the perioperative management of lung resection patients reduce the risk of acute lung injury?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was whether a conservative fluid management strategy in the perioperative management of lung resection patients is associated with a reduced incidence of postoperative acute lung injury (PALI) and/or acute respiratory distress syndrome (ARDS) in the recovery period. Sixty-seven papers were found using the reported search, of which 13 level III and 1 level IV evidence studies represented the best evidence to answer the question. Two retrospective case-control studies demonstrated a direct association between liberal fluid intake and the incidence of PALI/ARDS following lung resection on multivariate analysis (MVA) with odds ratios (ORs) of 1.42 (95% CI 1.09-4.32, P = 0.011) and 2.91 (1.9-7.4, P = 0.001). In non-PALI/ARDS cases, the mean intraoperative fluid infusion volume was significantly less [1.22 l (1.17-1.26) vs 1.68 l (1.46-1.9) P = 0.005], the fluid balance over the first 24 postoperative hours was significantly less [1.52 l positive (1.44-1.60) vs 2.0 l positive (1.6-2.4) P = 0.026] and cumulated intra- and postoperative fluid infusion was significantly less [2.0 ml/kg/h (1.7-2.3) vs 2.6 ml/kg/h (2.3-2.9) P = 0.003]. These data show that the difference between fluid regimes associated with an increased incidence of PALI/ARDS (i.e. 'liberal') and those which are not (i.e. 'conservative') is narrow but significant. However, this does not prove a causative role for liberal fluid in the multifactorial development of PALI/ARDS. On this best evidence, we recommend intra- and postoperative maintenance fluid to be administered at 1-2 ml/kg/h and that a positive fluid balance of 1.5 l should not be exceeded in the perioperative period with caution being exercised with regard to the adequacy of oxygen delivery. If the fluid balance exceeds this threshold, a high index of suspicion for PALI/ARDS should be adopted and escalation of the level of care should be considered. If a patient develops signs of hypoperfusion after these thresholds are exceeded, inotropic/vasopressor support should be considered.

Perioperative lung protection strategies in cardiothoracic anesthesia: are they useful?

Patients are at risk for several types of lung injury in the perioperative period. These injuries include atelectasis, pneumonia, pneumothorax, bronchopleural fistula, acute lung injury, and acute respiratory distress syndrome. Anesthetic management can cause, exacerbate, or ameliorate most of these injuries. Lung-protective ventilation strategies using more physiologic tidal volumes and appropriate levels of positive end-expiratory pressure can decrease the extent of this injury. This review discusses the effects of mechanical ventilation and its role in ventilator-induced lung injury with specific reference to cardiothoracic anesthesia.

Comparison of the PaO2/FiO2 ratio in sternotomy vs. thoracotomy in mitral valve repair: a randomised controlled trial

OBJECTIVE

Cardiac surgery through a thoracotomy using one-lung ventilation (OLV) is thought to be associated with worse postoperative pulmonary gas exchange than sternotomy using two-lung ventilation (TLV), but this has not been confirmed yet. We, therefore, compared postoperative pulmonary gas exchange after mitral valve repair between sternotomy (group TLV) and thoracotomy (group OLV).

DESIGN

Randomised controlled study.

SETTING

University teaching hospital.

PARTICIPANTS

Cardiac surgery patients.

INTERVENTION

Sternotomy or thoracotomy was used for mitral valve repair.

MEASUREMENTS

The ratio of arterial partial pressure of oxygen (PaO2) to fraction of inspired oxygen (FiO2) was compared in both groups before induction of anaesthesia (T0) and just before departure from the operating room to the ICU (T1). Fluid administration, transfusion requirements and urine output were checked intraoperatively. Postoperative haemoglobin (Hb), haematocrit (Hct) and creatinine were evaluated. Cardiopulmonary bypass (CPB) time, intubation time and ICU stay were also recorded.

RESULTS

The PaO2/FiO2 ratio (mean ± SD) at T1 was significantly lower than at T0 in both groups (326.9 ± 120.1 vs. 431.9 ± 73.7 mmHg in group TLV, P < 0.001; 374.9 ± 130.9 vs. 445.4 ± 73.7 mmHg in group OLV, P = 0.001), but did not differ significantly between the two groups. The doses of inotropes and vaopressors used were not significantly different between the groups. Intraoperative fluid administration, transfusion requirements, urine output and postoperative Hb/Hct and creatinine did not differ significantly between the groups. CPB time, intubation time and ICU stay also did not differ significantly between the groups.

CONCLUSION

Perioperative pulmonary function following OLV via a thoracotomy was not significantly worse than that following TLV via a sternotomy in mitral valve repair.

CLINICAL TRIAL REGISTRATION

Not registered.

Biomarkers of acute lung injury: worth their salt?

The validation of biomarkers has become a key goal of translational biomedical research. The purpose of this article is to discuss the role of biomarkers in the management of acute lung injury (ALI) and related research. Biomarkers should be sensitive and specific indicators of clinically important processes and should change in a relevant timeframe to affect recruitment to trials or clinical management. We do not believe that they necessarily need to reflect pathogenic processes. We critically examined current strategies used to identify biomarkers and which, owing to expedience, have been dominated by reanalysis of blood derived markers from large multicenter Phase 3 studies. Combining new and existing validated biomarkers with physiological and other data may add predictive power and facilitate the development of important aids to research and therapy.

Does preoperatively created right to left shunt adequately reflect hypoxemia during pneumonectomy for lung cancer?

BACKGROUND

No method is currently available for preoperative approximation of the patient's situation to the one existing during pneumonectomy in general anesthesia with alternations of single and double-lung ventilation in the lateral position. We hypothesized that a patient breathing the room air in the sitting position, with the main bronchus occluded by the inflatable catheter (aimed to predict a postpneumonectomy ventilatory function), could, at least in some aspects, simulate the intraoperative situation in certain clinical conditions discussed in the text. To evaluate the hypothesis, we used data of 15 candidates for pneumonectomy at increased risk, who underwent a spirometry with the left man bronchus occluded, as a part of the postoperative lung function prediction. Arterial blood samples (pO2, pCO2, saturation, and pH) were obtained before placement of the Fogarty catheter, than after at least 60s of normal breathing with the main bronchus occluded. Significant drop in pO2 (10.35±1.65 vs. 7.79±1.40 kPa) ensued within 1 min after occlusion of the main bronchus. All patients were able to perform spirometry in presence of induced hypoxemia without dyspnea that would require cessation of the procedure. These results, together with the absence of cardiac rhythm disorders, lead us to believe that they would behave in the same way during a pneumonectomy with alternations of single and double-lung ventilation. Such an assumption is based on the fact that breathing the room air is less favorable from the standpoint of oxygen delivery--the content of oxygen in the room air is smaller in the room air compared to that delivered through endotracheal tube. The practical implication of this hypothesis is that assessment of oxygenation during this procedure, additionally facilitates the preoperative risk assessment in patients undergoing pneumonectomy for lung cancer. Moreover, a slight postoperative oxygenation improvement and smaller loss in FEV1 in patients with moderate COPD, mean that COPD patients are likely to do a little bit better postoperatively than predicted.

Lung protective strategies in anaesthesia

Patients are at risk for several types of lung injury in the perioperative period including atelectasis, pneumonia, pneumothorax, acute lung injury, and acute respiratory distress syndrome. Anaesthetic management can cause, exacerbate, or ameliorate these injuries. This review examines the effects of perioperative mechanical ventilation and its role in ventilator-induced lung injury. Lung protective ventilatory strategies to specific clinical situations such as cardiopulmonary bypass and one-lung ventilation along with newer novel lung protective strategies are discussed.

Goal-directed Coagulation Management in Major Trauma

Severe tissue trauma is frequently associated with hemorrhagic shock and subsequent pronounced coagulopathy [1]. Uncontrolled bleeding is the second most common cause of death, and hemorrhage is directly responsible for 40 % of all trauma-related deaths [2]. Coagulopathy can be detected with standard coagulation tests immediately after arrival in the emergency room (ER) in approximately 25–35 % of all trauma patients [1], [2]. Moreover, early trauma-induced coagulopathy is associated with a 4-fold increase in mortality [1]. Blood coagulation monitoring is essential in order to assess the underlying coagulation disorder and to tailor hemostatic treatment. Thromboelastometry (TEM) and thrombelastography (TEG) are promising point-of-care technologies providing rapid information on the initiation process of clot formation, clot quality, and stability of the clot [3].

Comparison of two protective lung ventilatory regimes on oxygenation during one-lung ventilation: a randomized controlled trial

BACKGROUND

The efficacy of protective ventilation in acute lung injury has validated its use in the operating room for patients undergoing thoracic surgery with one-lung ventilation (OLV). The purpose of this study was to investigate the effects of two different modes of ventilation using low tidal volumes: pressure controlled ventilation (PCV) vs. volume controlled ventilation (VCV) on oxygenation and airway pressures during OLV.

METHODS

We studied 41 patients scheduled for thoracoscopy surgery. After initial two-lung ventilation with VCV patients were randomly assigned to one of two groups. In one group OLV was started with VCV (tidal volume 6 mL/kg, PEEP 5) and after 30 minutes ventilation was switched to PCV (inspiratory pressure to provide a tidal volume of 6 mL/kg, PEEP 5) for the same time period. In the second group, ventilation modes were performed in reverse order. Airway pressures and blood gases were obtained at the end of each ventilatory mode.

RESULTS

PaO2, PaCO2 and alveolar-arterial oxygen difference did not differ between PCV and VCV. Peak airway pressure was significantly lower in PCV compared with VCV (19.9 ± 3.8 cmH2O vs 23.1 ± 4.3 cmH2O; p < 0.001) without any significant differences in mean and plateau pressures.

CONCLUSIONS

In patients with good preoperative pulmonary function undergoing thoracoscopy surgery, the use of a protective lung ventilation strategy with VCV or PCV does not affect the oxygenation. PCV was associated with lower peak airway pressures.

Postresectional lung injury in thoracic surgery pre and intraoperative risk factors: a retrospective clinical study of a hundred forty-three cases

Introduction

Acute respiratory dysfunction syndrome (ARDS), defined as acute hypoxemia accompanied by radiographic pulmonary infiltrates without a clearly identifiable cause, is a major cause of morbidity and mortality after pulmonary resection. The aim of the study was to determine the pre and intraoperative factors associated with ARDS after pulmonary resection retrospectively.

Methods

Patients undergoing elective pulmonary resection at Adnan Menderes University Medical Faculty Thoracic Surgery Department from January 2005 to February 2010 were included in this retrospective study. The authors collected data on demographics, relevant co-morbidities, the American Society of Anesthesiologists (ASA) Physical Status classification score, pulmonary function tests, type of operation, duration of surgery and intraoperative fluid administration (fluid therapy and blood products). The primary outcome measure was postoperative ARDS, defined as the need for continuation of mechanical ventilation for greater than 48-hours postoperatively or the need for reinstitution of mechanical ventilation after extubation. Statistical analysis was performed with Fisher exact test for categorical variables and logistic regression analysis for continuous variables.

Results

Of one hundred forty-three pulmonary resection patients, 11 (7.5%) developed postoperative ARDS. Alcohol abuse (p = 0.01, OR = 39.6), ASA score (p = 0.001, OR: 1257.3), resection type (p = 0.032, OR = 28.6) and fresh frozen plasma (FFP)(p = 0.027, OR = 1.4) were the factors found to be statistically significant.

Conclusion

In the light of the current study, lung injury after lung resection has a high mortality. Preoperative and postoperative risk factor were significant predictors of postoperative lung injury.

Perioperative tidal volume and intra-operative open lung strategy in healthy lungs: where are we going?

Tidal volumes have tremendously decreased over the last decades from <15 ml kg(-1) to approximately 6 ml kg(-1) actual body weight. Guidelines, widely agreed and used, exist for patients with acute lung injury or acute respiratory distress syndrome (ARDS). However, it is questionable if data created in patients with acute lung injury or ARDS from ventilation on intensive care units can be transferred to healthy patients undergoing surgery. Consensus criteria regarding this topic are still missing because only a few randomised controlled trials have been performed to date, focussing on the use of the best intra-operative tidal volume. The same problem has been observed regarding the application of positive end-expiratory pressure (PEEP) and intra-operative lung recruitment. This article provides an overview of the current literature addressing the size of tidal volume, the use of PEEP and the application of the open-lung concept in patients without acute lung injury or ARDS. Pathophysiological aspects of mechanical ventilation are elucidated.

Effects of pneumonectomy on nitric oxide synthase expression and perivascular edema in the remaining lung of rats

Pneumonectomy is associated with high mortality and high rates of complications. Postpneumonectomy pulmonary edema is one of the leading causes of mortality. Little is known about its etiologic factors and its association with the inflammatory process. The purpose of the present study was to evaluate the role of pneumonectomy as a cause of pulmonary edema and its association with gas exchange, inflammation, nitric oxide synthase (NOS) expression and vasoconstriction. Forty-two non-specific pathogen-free Wistar rats were included in the study. Eleven animals died during or after the procedure, 21 were submitted to left pneumonectomy and 10 to sham operation. These animals were sacrificed after 48 or 72 h. Perivascular pulmonary edema was more intense in pneumonectomized rats at 72 h (P = 0.0131). Neutrophil density was lower after pneumonectomy in both groups (P = 0.0168). There was higher immunohistochemical expression of eNOS in the pneumonectomy group (P = 0.0208), but no statistically significant difference in the expression of iNOS. The lumen-wall ratio and pO(2)/FiO(2) ratio did not differ between the operated and sham groups after pneumonectomy. Left pneumonectomy caused perivascular pulmonary edema with no elevation of immunohistochemical expression of iNOS or neutrophil density, suggesting the absence of correlation with the inflammatory process or oxidative stress. The increased expression of eNOS may suggest an intrinsic production of NO without signs of vascular reactivity.

Evidence-based practice guidelines for plasma transfusion

BACKGROUND

There is little systematically derived evidence-based guidance to inform plasma transfusion decisions. To address this issue, the AABB commissioned the development of clinical practice guidelines to help direct appropriate transfusion of plasma.

STUDY DESIGN AND METHODS

A systematic review (SR) and meta-analysis of randomized and observational studies was performed to quantify known benefits and harms of plasma transfusion in common clinical scenarios (see accompanying article). A multidisciplinary guidelines panel then used the SR and the GRADE methodology to develop evidence-based plasma transfusion guidelines as well as identify areas for future investigation.

RESULTS

Based on evidence ranging primarily from moderate to very low in quality, the panel developed the following guidelines: 1) The panel suggested that plasma be transfused to patients requiring massive transfusion. However, 2) the panel could not recommend for or against transfusion of plasma at a plasma : red blood cell ratio of 1:3 or more during massive transfusion, 3) nor could the panel recommend for or against transfusion of plasma to patients undergoing surgery in the absence of massive transfusion. 4) The panel suggested that plasma be transfused in patients with warfarin therapy-related intracranial hemorrhage, 5) but could not recommend for or against transfusion of plasma to reverse warfarin anticoagulation in patients without intracranial hemorrhage. 6) The panel suggested against plasma transfusion for other selected groups of patients.

CONCLUSION

We have systematically developed evidence-based guidance to inform plasma transfusion decisions in common clinical scenarios. Data from additional randomized studies will be required to establish more comprehensive and definitive guidelines for plasma transfusion.

Acute lung injury after thoracic surgery

In this review, the authors discussed criteria for diagnosing ALI; incidence, etiology, preoperative risk factors, intraoperative management, risk-reduction strategies, treatment, and prognosis. The anesthesiologist needs to maintain an index of suspicion for ALI in the perioperative period of thoracic surgery, particularly after lung resection on the right side. Acute hypoxemia, imaging analysis for diffuse infiltrates, and detecting a noncardiogenic origin for pulmonary edema are important hallmarks of acute lung injury. Conservative intraoperative fluid administration of neutral to slightly negative fluid balance over the postoperative first week can reduce the number of ventilator days. Fluid management may be optimized with the assistance of new imaging techniques, and the anesthesiologist should monitor for transfusion-related lung injuries. Small tidal volumes of 6 mL/kg and low plateau pressures of < or =30 cmH2O may reduce organ and systemic failure. PEEP may improve oxygenation and increases organ failure-free days but has not shown a mortality benefit. The optimal mode of ventilation has not been shown in perioperative studies. Permissive hypercapnia may be needed in order to reduce lung injury from positive-pressure ventilation. NO is not recommended as a treatment. Strategies such as bronchodilation, smoking cessation, steroids, and recruitment maneuvers are unproven to benefit mortality although symptomatically they often have been shown to help ALI patients. Further studies to isolate biomarkers active in the acute setting of lung injury and pharmacologic agents to inhibit inflammatory intermediates may help improve management of this complex disease.