Developmental components of resting ventilation among high- and low-altitude Andean children and adults.

This paper evaluates the age-associated changes of resting ventilation of 115 high- and low-altitude Aymara subjects, of whom 61 were from the rural Aymara village of Ventilla situated at an average altitude of 4,200 m and 54 from the rural village of Caranavi situated at an average altitude of 900 m. Comparison of the age patterns of resting ventilation suggests the following conclusions: 1) the resting ventilation (ml/kg/min) of high-altitude natives is markedly higher than that of low-altitude natives; 2) the age decline of ventilation is similar in both lowlanders and highlanders, but the starting point and therefore the age decline are much higher at high altitude; 3) the resting ventilation that characterizes high-altitude Andean natives is developmentally expressed in the same manner as it is at low altitude; and 4) the resting ventilation (ml/kg/min) of Aymara high-altitude natives is between 40-80% lower than that of Tibetans.

Reasons for removal of rigid internal fixation devices in craniofacial surgery.

Despite the widespread use of rigid fixation techniques in craniofacial surgery, there is a paucity of studies in the literature that serve to better define the reasons for the subsequent removal of plates and screws. The current study appears to be the first to attempt to assess these issues among a broad range of craniofacial surgery patients. Fifty-five patients who underwent hardware removal following craniofacial surgery at the University of Michigan Medical Center between 1989 and 1995 were retrospectively studied via an in-depth chart review. Common reasons for hardware removal included palpable/prominent hardware in 19 patients (34.5%), loosening of plates and screws in 14 patients (25.5%), pain in 14 patients (25.5%), infection in 13 patients (23.6%), wound dehiscence/exposure of hardware in 11 patients (20%), and removal at the time of secondary procedures in 5 patients (9.1%). It is hoped that this study will serve as a tool to define more completely the risk of needing subsequent hardware removal among craniofacial surgery patients treated with rigid internal fixation.