Volume Management and Resuscitation in Thoracic Surgery

Pulmonary Complications in Esophagectomy Based on Intraoperative Fluid Rate: A Single-Center Study

OBJECTIVES

Esophagectomy is associated with significant morbidity and mortality. The authors assessed the relationship between intraoperative fluid (IOF) administration and postoperative pulmonary outcomes in patients undergoing a transthoracic, transhiatal, or tri-incisional esophagectomy.

DESIGN

Retrospective cohort study (level 3 evidence).

SETTING

Tertiary care referral center.

PARTICIPANTS

Patients who underwent esophagectomy from 2007 to 2017.

INTERVENTIONS

The IOF rate (mL/kg/h) was the predictor variable analyzed both as a continuous and binary categorical variable based on median IOF rate for this cohort (11.90 mL/kg/h).

MEASUREMENTS

Primary outcomes included rates of acute respiratory distress syndrome (ARDS) within ten days after esophagectomy. Secondary outcomes included rates of reintubation, pneumonia, cardiac or renal morbidity, intensive care unit admission, length of stay, procedure-related complications, and mortality. Multivariate regression analysis determined associations between IOF rate and postoperative outcomes. Analysis was adjusted for age, sex, body mass index, procedure type, year, and thoracic epidural use.

MAIN RESULTS

A total of 1,040 patients comprised this cohort. Tri-incisional esophagectomy was associated with a higher hospital mortality rate (7.8%) compared with transthoracic esophagectomy (2.6%, p = 0.03) or transhiatal esophagectomy (0.7%, p = 0.01). Regression analysis revealed a higher IOF rate was associated with greater ARDS within ten days (adjusted odds ratio [OR] = 1.03, p = 0.01). For secondary outcomes, a higher IOF rate was associated with greater hospital mortality (adjusted OR = 1.05, p = 0.002), although no significant association with 30-day hospital mortality was identified.

CONCLUSIONS

Increased IOF administration during esophagectomy may be associated with worse postoperative pulmonary complications, specifically ARDS. Future well-powered studies are warranted, including randomized, controlled trials comparing liberal versus restrictive fluid administration in this surgical population.

Intraoperative Anesthetic Management of the Thoracic Patient

The intraoperative anesthetic management for thoracic surgery can impact a patient's postoperative course, especially in patients with significant lung disease. One-lung ventilation poses an inherent risk to patients, including hypoxemia, acute lung injury, and right ventricular dysfunction. Patient-specific ventilator management strategies during one-lung ventilation can reduce postoperative morbidity.

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.