Value of perioperative Doppler echocardiography in patients undergoing major lung resection

Predictors of acute kidney injury after lung resection surgery: a retrospective case-control study

PURPOSE

Patients undergoing lung resection are at increased risk for acute kidney injury (AKI) in the immediate postoperative period, with important consequences for longer term morbidity and mortality. Lung resection surgery has unique considerations that could increase the risk of AKI, including lung resection volume, duration of one-lung ventilation (OLV), and intraoperative fluid restriction. Yet, specific risk factor data are lacking. The objective of this study was to identify independent risk factors for early AKI after lung resection surgery.

METHODS

We conducted a retrospective case-control study of all patients presenting for elective lung resection surgery at an academic medical centre over a four-year period. Cases were patients who experienced an AKI and control patients were those who did not experience an AKI, based on KDIGO criteria. Baseline demographics and comorbidities along with duration of OLV and amount of lung resected were collected by retrospective chart review. The data were analyzed using multivariable logistic regression to identify independent predictors of AKI.

RESULTS

Acute kidney injury occurred within 48 hr in 57/1,045 (5.5%; 95% confidence interval, 4.2 to 7.0) of patients. On multivariable analysis, our model of best fit included preoperative serum creatinine, male sex, use of angiotensin II receptor blockers, and duration of OLV. The rate of complications, intensive care unit admission, and risk of death were all higher in the group of patients who experienced AKI.

CONCLUSIONS

Acute kidney injury occurs frequently after lung resection surgery and is associated with increased risk of postoperative complications. Increased duration of OLV may be a risk factor for AKI in this population.

Right Ventricle Response to Major Lung Resection (the RIVER Study)

Backgrounds

Major lung resection is associated with high postoperative morbidity and mortality, especially due to cardiorespiratory complications. Right ventricle (RV) ejection, pulmonary artery (PA) pressure, and tone are tightly coupled. Since the RV is exquisitely sensitive to changes in afterload, an acute increase in RV outflow resistance (i.e., acute pulmonary embolism [PE]) will cause acute RV dilatation and, a reduction of left ventricle compliance too, rapidly spiraling to acute cardiogenic shock and death. We investigated the changing in RV performance after major lung resection.

Materials and Methods

We carried out transthoracic echocardiography (TTE) aiming at searching for the incidence of early RV systolic dysfunction (defined as tricuspid annulus plane systolic excursion [TAPSE] <17 cm, S'-tissue Doppler imaging <10 cm/s) and estimate the RV-PA coupling by the TAPSE/pulmonary artery pressures (PAPs) ratio after major lung resection. The TTE has been performed before and immediately after surgery.

Results

After the end of the operation the echocardiographic parameters of the RV function worsened. TAPSE decreased from 24 (21 ÷ 28) to 18 (16 ÷ 22) mm (P = 0.015) and PAPs increased from 26 (25 ÷ 30) to 30 (25 ÷ 39) mmHg (P = 0.013). TAPSE/PAPs ratio decreased from 0.85 (0.80 ÷ 0.90) to 0.64 (0.54 ÷ 0.79) mm/mmHg (P = 0.002).

Conclusions

In line with previous reports, after major lung resection the increase in afterload reduces the RV function, but the impairment remains clinically not relevant. The different clinical picture of an acute cor pulmonale due to PE implies that the pathogenesis of cardiac failure involves more pathways than the mere mechanic occlusion of the blood flow.

When Is It Safe to Operate for Lung Cancer? Selection of Fiscally Responsible Cardiopulmonary Function Tests for Limited Resection (Wedge Resection and Segmentectomy), Standard Lobectomy, Sleeve Lobectomy, and Pneumonectomy

Pulmonary function testing remains the central determinant of candidacy for pulmonary resection and indicator of perioperative risk. For patients with borderline pulmonary function, exercise testing can help determine surgical candidacy either via stair climbing or by obtaining a maximum oxygen consumption. The Thoracic Revised Cardiac Risk Index should be used to select patients for further cardiac testing. Patient comorbidities, medications, functional limitations, and smoking status are also requisite assessments of the preoperative evaluation that influence perioperative outcomes. A minimally invasive approach to pulmonary resection reduces perioperative risk and may be of most benefit to patients with borderline pulmonary function.

Cardiovascular Computed Tomography Findings after Pneumonectomy: Comparison to Lobectomy

RATIONALE AND OBJECTIVES

To identify and compare cardiovascular findings on computed tomography (CT) scans after pneumonectomy (PNX) with those after lobectomy (LOBX).

MATERIALS AND METHODS

Pre- and postoperative CT scans from 25 PNX patients were retrospectively analyzed and compared to those from 30 LOBX patients. The diameter of the main pulmonary artery (PA) and its ratio to the ascending aorta (PA/Ao) were determined. Cardiac morphometry values were ascertained by measuring maximum diameters of the right and left ventricle on axial (RV_axial, LV_axial) and four-chamber (RV_4-ch, LV_4-ch) views. RV_axial/LV_axial and RV_4-ch/LV_4-ch ratios were calculated. Vessel stumps were evaluated for thrombosis.

RESULTS

After PNX, PA (31.1 ± 5.8 mm vs 28.7 ± 5.4 mm, P = 0.003), PA/Ao (0.97 ± 0.15 vs 0.86 ± 0.12, P = 0.0001), and cardiac morphometry values significantly increased (RV_axial 43.6 ± 7.4 vs 39.4 ± 7.1, P = 0.029; RV_4-ch 41.1 ± 6.3 vs 37.6 ± 5.7, P = 0.041; RV_axial/LV_axial 1.18 ± 0.27 vs 1.03 ± 0.22, P = 0.04; RV_4-ch/LV_4-ch 1.17 ± 0.21 vs 1.02 ± 0.16, P = 0.03). There were no significant differences between right and left PNX. One case of PA stump thrombosis was identified after right PNX. LOBX resulted in a significant increase in PA (30.6 ± 4.3 vs 28.7 ± 3.5, P = 0.005) and PA/Ao (0.90 ± 0.09 vs 0.85 ± 0.10, P = 0.017), whereas cardiac morphometry values were not significantly changed compared to baseline values. No vessel stump thrombosis was observed after LOBX. In comparison to LOBX, all ascertained values were significantly elevated after PNX.

CONCLUSIONS

Morphologic alterations of the cardiovascular system following PNX can be identified on CT scans. Alterations are more distinct after PNX compared to LOBX.

Evaluation of left and right ventricular myocardial function after lung resection using speckle tracking echocardiography

The impact of major lung resections on myocardial function has not been well-investigated. We aimed to identify this impact through the use of speckle tracking echocardiography (STE) to evaluate the right and left ventricular myocardial function in patients who underwent lung resections.Thirty patients who had lung resections were recruited for this study. Ten patients who underwent pneumonectomies were matched by age and sex, with 20 patients who underwent lobectomies. STE was performed on both right and left ventricle (RV and LV). Strain values of pre and postlung resections were compared in both the pneumonectomy group and the lobectomy group. Comparison between the pneumonectomy group and the lobectomy group was also studied.Left ventricular ejection fraction remained normal (>55%), but significantly decreased after lung resection in both the pneumonectomy group and the lobectomy group. An accelerated heart rate was observed in both groups after lung resection, with the pneumonectomy group demonstrating extra rapid heart rate (P < 0.05). Strain values in the RV and LV decreased in both groups after lung resection, with the pneumonectomy group exhibiting a further decrease in longitudinal strain in LV and RV when compared with the lobectomy group (P < 0.05).Right and left ventricular dysfunction can occur after lung resection regardless of pneumonectomy or lobectomy, and lobectomy may have a less significant impact on myocardial functions. This study demonstrated that STE is able to detect acute cardiac dysfunction after lung resection.

Anesthetic management of the patient with dilated cardiomyopathy undergoing pulmonary resection surgery: a case-based discussion

Interactions between the cardiovascular and respiratory systems are complex and profound. General anesthesia, muscle relaxation, and positive-pressure ventilation all impose physiological effects on cardiovascular function. In patients presenting for pulmonary resection, additional effects resulting from positioning, 1-lung ventilation, surgical procedures, and contraction of the pulmonary vascular bed may impose an additional physiological burden. For most patients with adequate pulmonary and cardiovascular reserve, these effects are well tolerated. However, the cardiothoracic anesthesiologist may be asked to provide anesthetic care for patients with significantly reduced cardiac function who require potentially curative pulmonary resection for lung cancer. These patients present a major perioperative challenge and a thoughtful approach to intraoperative management is required. The authors review a case of a patient with severely impaired biventricular function who presented for elective pulmonary lobectomy in an attempt to effect a curative resection of lung cancer and present a discussion of physiological and pathophysiological considerations for clinical management.

Pre- and post-operative cardiac evaluation of dogs undergoing lobectomy and pneumonectomy

This study aimed to assess the influence of lobectomy and pneumonectomy on cardiac rhythm and on the dimensions and function of the right-side of the heart. Twelve dogs undergoing lobectomy and eight dogs undergoing pneumonectomy were evaluated preoperatively and one month postoperatively with electrocardiography and Doppler echocardiography at rest. Pulmonary artery systolic pressure (PASP) was estimated by the tricuspid regurgitation jet (TRJ) via the pulse wave Doppler velocity method. Systemic inflammatory response syndrome criteria (SIRS) were also evaluated based on the clinical and hematological findings in response to lobectomy and pneumonectomy. Following lobectomy and pneumonectomy, we predominantly detected atrial fibrillation and varying degrees of atrioventricular block (AVB). Dogs that died within seven days of the lobectomy (n = 2) or pneumonectomy (n = 1) had complete AVB. Preoperative right atrial, right ventricular, and pulmonary artery dimensions increased gradually during the 30 days (p<0.05) following pneumonectomy, but did not undergo significant changes during that same period after lobectomy. Mean PASP was 56.0 ± 4.5 mmHg in dogs having significant TRJ after pneumonectomy. Pneumonectomy, but not lobectomy, could lead to increases (p<0.01) in the SIRS score within the first day post-surgery. In brief, it is important to conduct pre- and postoperative cardiac evaluation of dogs undergoing lung resections because cardiac problems are a common postoperative complication after such surgeries. In particular, complete AVB should be considered a life-threatening complication after pneumonectomy and lobectomy. In addition, pneumonectomy appears to increase the likelihood of pulmonary hypertension development in dogs.

Effects of fluid resuscitation on cardiovascular performance after posttraumatic pneumonectomy

BACKGROUND

: Several factors have been implicated in the high-mortality rate of posttraumatic pneumonectomy. In this study, we evaluated the hemodynamic and echocardiographic changes induced by pneumonectomy and fluid resuscitation after hemorrhagic shock.

METHODS

: Fourteen dogs were bled to a target mean arterial pressure of 40 mmHg. The animals were assigned to two groups: control (no fluid resuscitation) and lactated Ringer's (3 x shed blood volume). The left pulmonary hilum was cross clamped, and the animals were observed for 60 minutes. Systemic hemodynamics was evaluated using Swan-Ganz, arterial catheter, and ultrasonic flow probe. Systemic O2-derived variables were calculated. Ejection fraction was determined by two-dimensional echocardiography.

RESULTS

: Fluid resuscitation improved the mean arterial pressure and systemic oxygen delivery. After pneumonectomy, no significant increase in right ventricular pressure was observed in the LR group. No signs of major ventricular dilation or changes in arterial oxygenation were observed.

CONCLUSION

: Our data suggest that pneumonectomy is not associated with early pulmonary hypertension; gentle fluid resuscitation improves cardiovascular performance and is not associated with an increase in right ventricular pressure.

Right heart function in thoracic surgery: role of echocardiography

PURPOSE OF REVIEW

As part of the preoperative evaluation, echocardiography provides noninvasive assessment of cardiovascular status in patients scheduled for lung resection, especially in the presence of chronic elevation of pulmonary arterial pressures. The goal of this review is to summarize the recent literature on the topic.

RECENT FINDINGS

Changes in right ventricular function can occur acutely during lung transplantation or occasionally during lung resection. In the postoperative period, changes in right heart function will depend on preexisting pulmonary hypertension, and whether it is exacerbated by worsening chronic obstructive pulmonary disease, pneumonia or development of the adult respiratory distress syndrome. Currently, it remains controversial whether routine lung resection leads to clinically significant changes in right heart function.

SUMMARY

The use of echocardiography in the perioperative setting can be useful in diagnosing and treating right ventricular dysfunction, especially when associated with hemodynamic instability unresponsive to conventional treatment, or arrhythmias, which all may occur after lung resection.

Suppression of right ventricular hypertrophy after extensive pulmonary resection in rats by granulocyte colony-stimulating factor

BACKGROUND

The objective of the present study was to investigate the effects of granulocyte colony-stimulating factor (G-CSF) on right ventricular hypertrophy following extensive pulmonary resection in rats.

MATERIALS AND METHODS

Adult rats were divided into four groups: (1) Group S (right thoracotomy only); (2) Group L (right three lobectomy); (3) Group LG10 (Group L+G-CSF [10microg/kg/d]); and (4) Group LG100 (Group L+G-CSF [100microg/kg/d]). At postoperative day 21, weight ratio of the right ventricular to the left ventricle plus septum (RV/LV+S, indicator of right ventricular hypertrophy) were measured, and a histopathological study was conducted to determine percentage wall thickness of peripheral pulmonary arteries and proliferating cell nuclear antigen labeling index (indicator of oxidative DNA damage) of right ventricles.

RESULTS

Mean RV/LV+S for Group S was 0.27+/-0.02, significantly smaller than that for the lobectomy groups (Group L, LG10, LG100; 0.47+/-0.05, 0.35+/-0.02, 0.38+/-0.05). G-CSF significantly suppressed right ventricular hypertrophy. Mean medial wall thickness of peripheral pulmonary arteries for Group S was 13.6% +/- 4.9%, significantly smaller than that for Group L (22.9% +/- 9.6%). Compared with Group L, G-CSF reduced medial wall thickness (LG10, 17.6% +/- 9.5%; LG100, 18.0% +/- 11.2%). Incidence of proliferating cell nuclear antigen positive nuclei for Group S was 1.07% +/- 0.49%, significantly smaller than that for Group L (13.77% +/- 5.87%). G-CSF significantly reduced the incidence of proliferating cell nuclear antigen positive nuclei (LG10, 4.04% +/- 2.14%; LG100, 3.18% +/- 1.66%).

CONCLUSIONS

G-CSF administration not only reduce medial wall thickness of peripheral pulmonary arteries but also directly protect cardiomyocytes of the right ventricle, thus suppressing right ventricular hypertrophy. These results suggest that low-dose G-CSF administration can prevent right heart failure following extensive pulmonary resection.

Respiratory failure following pulmonary resection

Improvements in the perioperative management of the patient undergoing pulmonary resections have reduced postoperative complication rates steadily in the last several decades. However, postresection respiratory failure, particularly lung injury with no discernible cause, remains a major cause of morbidity and mortality. Because the incidence of this entity is relatively low, the terminology, pathogenesis, and optimal management are poorly delineated in the literature. The purpose of this review is to describe the criteria used to define postresection lung injury, discuss the possible etiologic factors, and outline currently available treatment strategies.

Anesthetic management of patients undergoing extrapleural pneumonectomy for mesothelioma

PURPOSE OF REVIEW

Extrapleural pneumonectomy is a radical and aggressive surgery that presents a great challenge to the thoracic anesthesiologist. This surgery is performed routinely by only a few centers in the world and this review represents our institution's experience in anesthetic care.

RECENT FINDINGS

Prominent among the developing multimodal treatment options is the combination of extrapleural pneumonectomy with intraoperative intracavitary hyperthermic chemotherapy. Outcome survival benefits have recently been demonstrated for the less completely cytoreductive pleurectomy procedure when combined with intraoperative intracavitary hyperthermic chemotherapy and trials are well under way for extrapleural pneumonectomy plus intraoperative intracavitary hyperthermic chemotherapy. Anesthetic management of extrapleural pneumonectomy is further impacted by these developments.

SUMMARY

Anesthetic management importantly contributes to containment of the perioperative complications of extrapleural pneumonectomy. An appreciation of the technical aspects and physiologic disruptions associated with extrapleural pneumonectomy is critical to effective management. While data on this relatively uncommon surgical procedure are scarce, some referral centers have accumulated extensive experience. This review summarizes relevant surgical aspects and anesthetic insights from the Brigham and Women's Hospital experience. Included are the anesthetic implications of intraoperative intracavitary hyperthermic chemotherapy in combination with extrapleural pneumonectomy - an emerging therapeutic option in the treatment of malignant pleural mesothelioma.

Long-term Doppler echocardiographic evaluation of the right heart after major lung resections

OBJECTIVE

The effects of major lung resections on cardiac function in the medium and long term have not been thoroughly evaluated. We have studied right heart function with serial Doppler echocardiography in patients undergoing lobectomy and pneumonectomy during 4 years of follow-up after surgery.

METHODS

Thirty-six patients undergoing lobectomy and 15 receiving pneumonectomy were evaluated with one- and two-dimensional Doppler standard transthoracic echocardiography before surgery and 1 week, 3 months, 6 months, 1 year, and 4 years postoperatively. We have studied the right midventricular diastolic diameter (RVDD), the right ventricle free wall thickness, the tricuspid valve insufficiency (TVI) and regurgitation jet (TRJ), and the pulmonary artery systolic pressure (PASP).

RESULTS

None of the patients died within the first postoperative year. After lobectomy there were no significant modifications of any variable at any time. RVDD progressively increased after pneumonectomy (26.5+/-2.2mm preoperatively vs 34.3+/-7.6 at 4 years; p<0.001). Four years after surgery all patients undergoing pneumonectomy had moderate TVI while only 55% of patients receiving lobectomy showed it (low grade in 50% and moderate in 5%). In this group of patients PASP increased from 26.1+/-2.6 mmHg preoperatively to 34.3+/-7.6 mmHg at 4 years (p<0.00001).

CONCLUSIONS

Right ventricle modifications are clearly evident after pneumonectomy and even if they do not show a clear clinical impact they should not be neglected.

Cardiovascular Complications After Lung Surgery

Cardiovascular complications following thoracic surgery remain a challenge to the physician, the hospital, and the health care system. These events add significantly to morbidity, mortality, and the cost of care of the general thoracic surgery patient. A proactive approach to identify patients at high risk for such complications is needed. In this manner, one may enhance prevention and treatment if problems occur. A thoughtful and complete preoperative risk assessment can identify patients who have potential contributing comorbidities, leading to a reduced incidence of postoperative events. Standardization of preoperative, intraoperative, and postoperative care can reduce postoperative events. Implementation of guidelines and pathways that are evidence based can lead to enhanced patient care, better patient and staff satisfaction, and improved outcomes from the operation. Although postoperative cardiac events cannot be completely eliminated from the thoracic surgery population, the prevention, treatment, and follow-up strategies outlined herein can attenuate these significant morbid and mortal events.

Acute effects of lobectomy on right ventricular ejection fraction and mixed venous oxygen saturation

BACKGROUND

Traditional methods of assessing the operative risk for lung resection provide only a modest ability to predict postoperative morbidity and mortality. The aim of this study was to evaluate the effect of lobectomy on pulmonary hemodynamic and gas exchange variables using the RV thermodilution ejection fraction/oximetric catheter.

METHODS

We evaluated the acute postoperative effects of lung resection on hemodynamic and gas exchange parameters in 30 patients. Anesthesia was induced with thiopentone sodium and maintained with midazolam, fentanyl and pipecuronium. Intubation was performed with a double-lumen, left-sided endobronchial tube for one lung ventilation. The hemodynamic and gas exchange parameters were recorded before and after induction of anesthesia, and two hours after lung resection. These parameters were also recorded after the classification of the patients according to the underlying lung pathology.

RESULTS

Lobectomy was associated with significant hemodynamic changes and good maintenance of gas exchange variables. SVI, LVSWI and RVEF were significantly decreased in the early postoperative period after lung resection. MPAP, COP, CI, SVRI, PVRI, RVSWI, and RVEDVI showed no significant changes during the perioperative period. SVO2 showed a significant increase after lung resection when compared with preinduction values, while VO2 significantly decreased. SaO2, a-A PO2, QS-QT, DO2, and O2ER showed no significant changes during the perioperative period.

CONCLUSIONS

We conclude that in the acute post-resection period (up to 2 hours postoperatively) there is right and left ventricular dysfunction with good maintenance of gas exchange.

Acute lung injury and acute respiratory distress syndrome after pulmonary resection

The occurrence of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) after thoracic surgery are perplexing and persistent problems. Variously described as postpneumonectomy pulmonary edema, noncardiogenic pulmonary edema, and postlung resection pulmonary edema, ALI and ARDS may be considered a single entity, with ALI being the less severe form of ARDS. It is characterized by the acute onset of hypoxemia with radiographic infiltrates consistent with pulmonary edema, without elevations in the pulmonary capillary wedge pressure. Although this syndrome does not occur frequently and is usually without identifiable cause, the mortality is high. However, the phenomenon has not been rigorously studied owing to the low incidence, with primarily retrospective case series reported. Thus, the nomenclature, risks, and pathogenesis are not well defined. Interest in this syndrome has recently been renewed as the rate of other perioperative complications has declined. ALI/ARDS is reviewed with a focus on potential etiologies and the spectrum of available interventions.

Preoperative Assessment: An Anesthesiologist's Perspective

Advances in anesthesia and surgery have made it so that almost any patient with a resectable lung malignancy is now an operative candidate given a full understanding of the risks and after appropriate investigation. This situation necessitates a change in the paradigm that anesthesiologists use for preoperative assessment. Understanding and stratifying the perioperative risks allows the anesthesiologist to develop a systematic focused approach to these patients at the time of the initial contact and immediately before induction, which can be used to guide anesthetic management.

Anesthetic strategies for patients undergoing extrapleural pneumonectomy

Anesthetic management of patients with extrapleural pneumonectomy may contribute to risk reduction, and it differs from management of patients with standard pneumonectomy in several respects. Hemodynamic and intravascular fluid management is complicated by the significantly greater blood loss and impairments of venous return imposed by weighty tumors and the blunt dissection process. There are greater risks of catastrophic (central) bleeding, dysrhythmias, cardiac herniation, and electrocardiographic changes. Restrictive forces increase the likelihood of dependent lung atelectasis during single-lung ventilation. Preoperative assessment of cardiopulmonary reserve remains an imprecise process. Awareness of these risks and limitations enables the anesthesiologist to understand, anticipate, and potentially preempt many intraoperative problems.

Risk Factors for Acute Lung Injury After Thoracic Surgery for Lung Cancer

Acute lung injury (ALI) may complicate thoracic surgery and is a major contributor to postoperative mortality. We analyzed risk factors for ALI in a cohort of 879 consecutive patients who underwent pulmonary resections for non-small cell lung carcinoma. Clinical, anesthetic, surgical, radiological, biochemical, and histopathologic data were prospectively collected. The total incidence of ALI was 4.2% (n = 37). In 10 cases, intercurrent complications (bronchopneumonia, n = 5; bronchopulmonary fistula, n = 2; gastric aspiration, n = 2; thromboembolism, n = 1) triggered the onset of ALI 3 to 12 days after surgery, and this was associated with a 60% mortality rate (secondary ALI). In the remaining 27 patients, no clinical adverse event preceded the development of ALI-0 to 3 days after surgery-that was associated with a 26% mortality rate (primary ALI). Four independent risk factors for primary ALI were identified: high intraoperative ventilatory pressure index (odds ratio, 3.5; 95% confidence interval, 1.7-8.4), excessive fluid infusion (odds ratio, 2.9; 95% confidence interval, 1.9-7.4), pneumonectomy (odds ratio, 2.8; 95% confidence interval, 1.4-6.3), and preoperative alcohol abuse (odds ratio, 1.9; 95% confidence interval, 1.1-4.6). In conclusion, we describe two clinical forms of post-thoracotomy ALI: 1). delayed-onset ALI triggered by intercurrent complications and 2). an early form of ALI amenable to risk-reducing strategies, including preoperative alcohol abstinence, lung-protective ventilatory modes, and limited fluid intake.

IMPLICATIONS

In an observational study including all patients undergoing lung surgery, we describe two clinical forms of acute lung injury (ALI): a delayed-onset form triggered by intercurrent complications and an early form associated with preoperative alcohol consumption, pneumonectomy, high intraoperative pressure index, and excessive fluid intake over the first 24 h.

Cardiac complications after noncardiac thoracic surgery: an evidence-based current review

Despite advances in perioperative management, thoracic surgery remains a high-risk procedure for many patients. A systematic review of cardiac complications after thoracic surgery is presented. Most reviews about noncardiac thoracic surgery discuss postoperative analgesic regimens and pulmonary complications. In the present review, we also discuss atrial fibrillation as the most frequently encountered cardiac side effect. An evidence-based approach to other complications, such as myocardial ischemia, pulmonary edema, embolism, and shunt, is described. Furthermore, we offer recommendations for daily practice.

Natriuretic peptides after pulmonary resection

BACKGROUND

Little is known about alterations in the levels and influence of natriuretic peptide (NP) on cardiopulmonary function after pulmonary resection for lung cancer. This study was designed to investigate the patterns and activity of NP after pulmonary resection.

METHODS

We investigated changes in plasma A-type (atrial) NP and B-type (brain) NP (BNP) using radioimmunoassay, in lung cancer patients before and after lobectomy (n = 15) or pneumonectomy (n = 10). Patient characteristics, respiratory function, operative time, blood loss, intraoperative fluid administration, and intraoperative urine output in both groups were also compared. Pulmonary hemodynamic variables were monitored continuously.

RESULTS

Plasma concentrations of A-type NP and BNP did not differ between the two groups preoperatively. However, the group undergoing pneumonectomy exhibited higher concentrations of A-type NP and BNP than the group undergoing lobectomy on postoperative days 3 and 7. Alterations in A-type NP and BNP after pulmonary resection therefore differed according to the volume of lung tissue resected. Both mean pulmonary artery pressure and total pulmonary vascular resistance increased significantly in the pneumonectomy group. The total pulmonary vascular resistance on postoperative day 3 correlated with the plasma BNP concentration in the pneumonectomy group.

CONCLUSIONS

A-type NP and BNP effectively compensate for the right ventricular dysfunction noted after pulmonary resection, and this is more evident after pneumonectomy than after lobectomy. Changes in ventricular activity associated with changes in plasma BNP and total pulmonary vascular resistance are indicative of cardiopulmonary adjustments after pneumonectomy.

Postoperative arrhythmias and conduction disorders

Cardiac arrhythmias are common in the perioperative period. Most arrhythmias are clinically benign. Occasionally, cardiac arrhythmias and conduction disturbances can pose a major additional risk to the patient in the perioperative and postoperative periods. The current availability of a wide array of techniques for controlling serious arrhythmias--pharmacologic, electrical, and interventional--enable the physician to manage most arrhythmias and conduction disturbances successfully. The added risks posed by arrhythmias and conduction disturbances in the perioperative period now can be minimized.

Preoperative assessment for pulmonary resection

Because of recent advances in anesthesia and surgery, almost any patient with a resectable lung malignancy is now an operative candidate, given a full understanding of the risks and provided he or she is investigated appropriately. This progress necessitates a change in the paradigm that one uses for preoperative assessment. Understanding and stratifying the perioperative risks allows the anesthesiologist to develop a systematic focused approach to these patients at the time of the initial contact and immediately before induction, which then can be used to guide anesthetic management (Fig. 7).

Perioperative alterations in plasma endothelin-1 and echocardiographic correlates of right heart function

OBJECTIVE

To determine whether greater changes in plasma endothelin-1 (ET-1) concentrations and right ventricular systolic pressure occur after major thoracic surgery than after major abdominal operations.

DESIGN

Prospective study.

SETTING

University hospital.

PARTICIPANTS

Patients undergoing elective thoracotomies (n = 12) or laparotomies (n = 10).

INTERVENTIONS

ET-1 was measured from blood obtained before anesthesia and again on postoperative days 1, 2, 3, and 5 (or 6). Transthoracic echocardiography was performed before surgery and on postoperative day 2 to evaluate right-sided heart function.

MEASUREMENTS AND MAIN RESULTS

After abdominal and thoracic surgery, systemic and estimated pulmonary vascular pressures were normal in both groups and unaffected by surgery. Plasma ET-1 concentrations decreased from baseline values during the first postoperative week with no differences between the groups.

CONCLUSIONS

In patients without organic heart disease, plasma ET-1 levels do not increase in response to major abdominal or thoracic surgery. Whether or not plasma ET-1 concentrations are elevated in patients developing clinically significant postoperative pulmonary hypertension requires further study.

Effect of oxygen on pulmonary hemodynamics and incidence of atrial fibrillation after noncardiac thoracotomy

OBJECTIVE

The mechanism of postthoracotomy atrial fibrillation (AF) could be related to right ventricular (RV) strain. The effect of oxygen on the occurrence of postoperative AF and on RV function was studied.

DESIGN

A prospective, randomized study.

SETTING

A university hospital.

PARTICIPANTS

Twenty-four noncardiac thoracotomy patients.

INTERVENTIONS

At the end of the postoperative anesthesia care unit period, the patients were randomly allocated to receive 35% oxygen until either the third (P = prolonged group) or the first postoperative morning (S = short group).

MEASUREMENTS AND MAIN RESULTS

Measurement of hemodynamic variables using a thermodilution pulmonary artery catheter, oxygenation, concentration of plasma atrial natriuretic peptide (ANP) and Holter monitoring were started preoperatively and continued for the 3 postoperative days (PODs). Systolic RV pressure (systolic RVP) and pulmonary vascular resistance (PVR) increased postoperatively only in group S. Major changes in RV performance were not seen with echocardiography or the thermodilution method in any patient. Silent episodes of AF occurred in three patients (25%) in group P and in one patient (8%) in group S (not significant [NS]) without deviations in plasma ANP concentration. On each of the 3 PODs, all patients were exposed to 60% oxygen for 15 minutes. Systolic RVP decreased significantly during the exposure to 60% oxygen only in group S, but not in patients developing AF. Predictive factors for AF were a high preoperative PVR, intraoperative bleeding necessitating volume loading, and elevated systolic RVP immediately after thoracotomy.

CONCLUSION

Short episodes of AF occurred irrespective of the length of oxygen therapy. Occurrence of AF could not be explained by changes in RV function.

Postoperative Cardiac Arrhythmias: Prevention and Management

Supraventricular arrhythmias or supraventricular tachy cardias (SVT) frequently occur after thoracic surgery and have been associated with prolonged hospital stays. The reported incidence of supraventricular ar rhythmias in this patient population ranges from 9% to 40%, with factors such as extent of surgery markedly influencing the incidence. SVT has been reported to be 12% to 16% after lobectomy, 20% to 30% after pneumo nectomy, and as much as 40% after extrapleural pneu monectomy for malignant pleural mesothelioma. Pa tients who develop SVT have a higher rate of intensive care unit admission and higher 30-day mortality. SVT occurrence appears to be an important marker of poor cardiopulmonary reserve in patients who developed significant morbidity after thoracic surgery. It is pos sible that the rate of SVT occurrence increases propor tionally with extent of neural trauma to cardiac plexus structures in older patients. The timing of SVT onset is likely related to the high adrenergic activity of the postsurgery state and the resolution of a graded inflam matory process corresponding to the amount of blunt or sharp surgical trauma to sympathovagal nerve fibers innervating the sinus node. This article will focus on new issues leading to improved understanding of the pathophysiology and mechanisms of SVT after surgery. New approaches directed at prophylaxis and acute therapy of SVT are also discussed.