Predictors for postoperative cranial nerve complications in carotid body tumor resection: a retrospective cohort study.

INTRODUCTION: Carotid body tumors (CBTs) are slow-growing benign tumors. Therefore, surgical resection is considered in case of tumor growth. The timing of surgery is of the utmost importance as the risk of iatrogenic surgical complications increases when resecting larger tumors, whereas on the other hand, resections for asymptomatic small CBT should be prevented. The primary aim of this study was to identify which tumor size or dimension is most accurate to predict nerve injury in patients undergoing resection of a CBT. MATERIAL AND METHODS: This retrospective cohort study included patients who underwent surgical resection of CBT at the university hospital in South-Holland. Baseline patient characteristics and tumor measurements were retrieved from the medical records. The authors assessed how the different methods of measuring the size of the tumor were interrelated using Pearson correlation. Logistic regression was used to assess which variables were independently associated with nerve injury, including age at surgery, Shamblin classification, and those dimensions that captured different aspects of tumor size (rather than measuring the same as shown by high correlations) as possible independent variables. RESULTS: In 125 patients, 143 CBTs were resected whereof in 35 cases cranial nerve injury occurred, (transient in 16 cases and permanent in 19 cases). The risks for nerve injury increased with larger tumor size and the Shamblin classification. Logistic regression analysis showed that the anterior-posterior (AP) diameter significantly increased the odds of a nerve injury, a doubling for every 1 cm increase in AP diameter [odds ratio (95% CI) 2.12 (1.29-3.48), P =0.003]. CONCLUSION: This study shows that measured tumor size in the AP plane is a strong predictor for postoperative nerve injury of a CBT resection. This predictor can be used in the daily clinic to give insight in operative risks. More research is needed in order to select the most appropriate time window for CBT resection.

Identifying Factors Influencing Decision Making in Patients Diagnosed with Carotid Body Tumors: An Exploratory Study.

BACKGROUND: Carotid body tumors (CBTs) are rare highly vascularized and slow enlarging tumors arising from the paraganglionic tissue at the carotid bifurcation. Main treatment options for CBTs are surgical resection or "wait and scan" strategy. The choice for either strategy may be equally good medically in many patients. A structured "shared decision making" (SDM) might be helpful for guiding patients. OBJECTIVES: To develop an SDM strategy for the surgical treatment, we aim to (1) identify considerations and factors involved in the decision making of patients with CBTs and (2) evaluate the current practice in our clinic and explore the opinions of patients on their treatment. METHODS: This exploratory study was conducted in patients of the Leiden University Medical Centre (LUMC), The Netherlands. Patients who met the inclusion criteria were invited for a semi-structured interview. All conversations were fully audiotaped and transcripted. RESULTS: Fifteen patients were included and interviewed. Ten of these patients underwent previously surgical resection of at least one tumor. Five patients underwent the wait and scan policy. The most important factors influencing decision making in CBT treatment are family, fears, co-consultants, and doctor-patient relationship. CONCLUSIONS: This study has identified the factors influencing decision making in CBT and should be considered during consultations. The decision for surgery or not was mainly influenced by physician preferences and family members' prior experiences.

Ventilator-derived carbon dioxide production to assess energy expenditure in critically ill patients: proof of concept.

INTRODUCTION: Measurement of energy expenditure (EE) is recommended to guide nutrition in critically ill patients. Availability of a gold standard indirect calorimetry is limited, and continuous measurement is unfeasible. Equations used to predict EE are inaccurate. The purpose of this study was to provide proof of concept that EE can be accurately assessed on the basis of ventilator-derived carbon dioxide production (VCO2) and to determine whether this method is more accurate than frequently used predictive equations. METHODS: In 84 mechanically ventilated critically ill patients, we performed 24-h indirect calorimetry to obtain a gold standard EE. Simultaneously, we collected 24-h ventilator-derived VCO2, extracted the respiratory quotient of the administered nutrition, and calculated EE with a rewritten Weir formula. Bias, precision, and accuracy and inaccuracy rates were determined and compared with four predictive equations: the Harris-Benedict, Faisy, and Penn State University equations and the European Society for Clinical Nutrition and Metabolism (ESPEN) guideline equation of 25 kcal/kg/day. RESULTS: Mean 24-h indirect calorimetry EE was 1823 ± 408 kcal. EE from ventilator-derived VCO2 was accurate (bias +141 ± 153 kcal/24 h; 7.7 % of gold standard) and more precise than the predictive equations (limits of agreement -166 to +447 kcal/24 h). The 10 % and 15 % accuracy rates were 61 % and 76 %, respectively, which were significantly higher than those of the Harris-Benedict, Faisy, and ESPEN guideline equations. Large errors of more than 30 % inaccuracy did not occur with EE derived from ventilator-derived VCO2. This 30 % inaccuracy rate was significantly lower than that of the predictive equations. CONCLUSIONS: In critically ill mechanically ventilated patients, assessment of EE based on ventilator-derived VCO2 is accurate and more precise than frequently used predictive equations. It allows for continuous monitoring and is the best alternative to indirect calorimetry.