title: Baroreflex and chemoreflex function after bilateral carotid body tumor resection.
abstract: OBJECTIVE
  To investigate whether bilateral carotid body tumor resection invariably and chronically affects arterial baroreflex or peripheral chemoreflex function.
  
  
  METHODS
  We studied eight consecutive patients (two men and six women; ages 48.1 +/- 11.8 years), a median time of 3.4 years (range 1.3-20.6 years) after bilateral carotid body tumor resection, and 12 healthy control individuals (eight men and four women; ages 53.7 +/- 10.1 years). Baroreflex sensitivity (phenylephrine), blood pressure and its variability (24 h Spacelabs and 5 h Portapres recordings), responses to standard cardiovascular reflex tests and the ventilatory responses to normocapnic and hypercapnic hypoxia were assessed.
  
  
  RESULTS
  Baroreflex sensitivity was lower in patients (6.4 +/- 7.2 ms/mmHg) than in controls (14.7 +/- 6.6 ms/mmHg; P +/- 0.011). Mean office blood pressure and heart rate were normal in patients (123.3 +/- 11.9/79.0 +/- 7.3 mmHg and 67.5 +/- 9.4 beats/min, respectively) and controls (117.8 +/- 10.6/74.0 +/- 6.8 mmHg and 61.1 +/- 9.2 beats/min, respectively). Blood pressure variability was increased during ambulatory measurements. Three patients exhibited orthostatic hypotension. The Valsalva ratio, an index of baroreflex-mediated cardiovagal innervation, was lower in patients (1.4 +/- 0.2) than in controls (1.8 +/- 0.5; P +/- 0.008). The normocapnic ventilatory response to hypoxia was absent in all patients, whereas a small residual response to hypoxia was observed under hypercapnic conditions in two patients.
  
  
  CONCLUSIONS
  Bilateral carotid body tumor resection results in heterogeneous expression of arterial baroreflex dysfunction, whereas the normocapnic hypoxic drive is invariably abolished as a result of peripheral chemoreflex failure.
authors.affiliation: Department of General Internal Medicine (541), Department of Otorhinolaryngology, University Medical Center St Radboud, Geert Grooteplein Zuid 8, PO Box 9101, 6500 HB Nijmegen, The Netherlands. H.Timmers@aig.azn.nl
authors.forename: Henri J L M
authors.initials: HJ
authors.lastname: Timmers
authors.forename: John M
authors.initials: JM
authors.lastname: Karemaker
authors.forename: Wouter
authors.initials: W
authors.lastname: Wieling
authors.forename: Henri A M
authors.initials: HA
authors.lastname: Marres
authors.forename: Hans T M
authors.initials: HT
authors.lastname: Folgering
authors.forename: Jacques W M
authors.initials: JW
authors.lastname: Lenders
mesh_terms: D000328:Adult; D000368:Aged; D017704:Baroreflex / Q000187:drug effects / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D002344:Carotid Body / Q000503:physiopathology / Q000601:surgery; D002345:Carotid Body Tumor / Q000503:physiopathology / Q000601:surgery*; D016022:Case-Control Studies; D002628:Chemoreceptor Cells / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010656:Phenylephrine / Q000494:pharmacology
chemical_list: D010656:Phenylephrine