How to perform indexing of extravascular lung water: a validation study.

BACKGROUND: Extravascular lung water is a quantitative marker of the amount of fluid in the thoracic cavity besides the vasculature. Indexing to both predicted and actual body weight have been proposed to compare different individuals and provide a uniform range of normal. OBJECTIVE: We explored extravascular lung water measured by single-indicator transpulmonary thermodilution in a large cohort of patients without cardiopulmonary instability, in order to evaluate current and alternative indexing methods. DESIGN: Prospective, observational. SETTING: Neurosurgical ICU in a tertiary referral academic teaching hospital. PATIENTS: One hundred and one consecutive patients requiring elective brain tumor surgery and postoperative ICU surveillance. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Indexed to predicted body weight, females had a mean extravascular lung water of 9.1 (SD=3.1, range: 5-23) mL/kg and males of 8.0 (SD=2.0, range: 4-19) mL/kg (p<0.001). Values indexed to predicted body weight were inversely correlated with the patient's height (p<0.001). Indexed to the traditionally used actual body weight, data showed a significant relationship to weight (p<0.001) and gender (p<0.05). In contrast, indexing to body height presented a method without dependencies on height, weight, or gender, yielding a uniform 95% confidence interval of 218-430 mL/m. Extravascular lung water increased with positive perioperative fluid balance (p=0.04). CONCLUSIONS: Using either predicted or actual body weight for indexing extravascular lung water does not lead to independence of height, weight, and gender of the patient. Specifying a fixed range of normal or a uniform upper threshold for all patients is misleading for either method, despite widespread use. Our data suggest that indexing extravascular lung water to height is superior to weight-based methods. As we are not aware of any abnormal hemodynamic profile for brain tumor patients, we propose our findings to be a close approximation to normal values.

Global end-diastolic volume acquired by transpulmonary thermodilution depends on age and gender in awake and spontaneously breathing patients.

INTRODUCTION: Volumetric parameters acquired by transpulmonary thermodilution had been repeatedly proven superior to filling pressures for estimation of cardiac preload. Up to now, the proposed normal ranges were never studied in detail. We investigated the relationship of the global end-diastolic volume (GEDV) acquired by transpulmonary thermodilution with age and gender in awake and spontaneously breathing patients. METHODS: Patients requiring brain tumor surgery were equipped prospectively with a transpulmonary thermodilution device. On postoperative day one, thermodilution measurements were performed in 101 patients ready for discharge from the ICU. All subjects were awake, spontaneously breathing, hemodynamically stable and free of catecholamines. RESULTS: Main finding was a dependence of GEDV on age and gender, height and weight of the patient. Age was a highly significant non-linear coefficient for GEDV with large inter-individual variance (p < 0.001). On average, GEDV was 131.1 ml higher in males (p = 0.027). Each cm body height accounted for 13.0 ml additional GEDV (p < 0.001). GEDV increased by 2.90 ml per kg actual body weight (p = 0.043). Each cofactor, including height and weight, remained significant after indexing GEDV to body surface area using predicted body weight. CONCLUSIONS: The volumetric parameter GEDV shows a large inter-individual variance and is dependent on age and gender. These dependencies persist after indexing GEDV to body surface area calculated with predicted body weight. Targeting resuscitation using fixed ranges of preload volumes acquired by transpulmonary thermodilution without concern to an individual patient's age and gender seems not to be appropriate.

Meningioma surgery in the elderly: outcome and validation of 2 proposed grading score systems.

BACKGROUND: Although population age increases, published evidence on meningioma treatment in the elderly is scarce. OBJECTIVE: In order to improve selection for surgery, we investigated our patients' collective, using 2 proposed risk assessment systems, the Clinical-Radiological Grading System (CRGS) and the SKALE score (sex, Karnofsky, American Society of Anesthesiology [ASA] score, location, edema). METHODS: We retrospectively assessed morbidity and mortality in 164 patients aged ≥ 65, operated on for an intracranial meningioma. Medical and surgical records were reviewed and analyzed. CRGS and SKALE scores were calculated. The ability of both CRGS and SKALE and all single factors to predict death within 12 months was analyzed by the use of multivariate logistic regression modeling. RESULTS: Eleven patients died (6.7%). Logistic regression for CRGS/SKALE showed a significant relationship with 12 months mortality. Age, Simpson resection grade, and sex were not significant predictors when investigated alone. In multivariate logistic regression, including all proposed factors, only concomitant disease and edema (CRGS) as well as ASA score and preoperative Karnofsky Performance Scale (SKALE) showed a significant relationship to mortality. After stepwise reduction of the full multivariate regression model to its significant terms, only concomitant disease and ASA remained significant for CRGS (P < .001) and SKALE (P = .003), respectively. CONCLUSION: Meningioma resection in the elderly is possible with some mortality. We were unable to reproduce the utility of 2 proposed grading systems for mortality prediction when extending to younger patients. In single-factor analysis, only concomitant disease and ASA score remained significant. The decision whether to operate should be taken individually. Patients with severe concomitant disease or high ASA score should be advised not to undergo surgical therapy independently from other factors.