Gold weights are well tolerated and effective in managing paralytic lagophthalmos. An open surgical technique with direct suture fixation of the gold weight to the tarsal plate produced fewer complications than inserting the lid load into a prefashioned tissue pocket in the preseptal space through a small lateral skin incision.

Effects of inspiratory tracheal occlusion (TO) on respiratory duration (inspiratory and expiratory duration), ventilation, and the peak integrated diaphragm electromyographic (integral of EMGdi) response were tested in 16 anesthetized cats before and after decerebellation with and without vagal input. The same protocols were repeated in the decerebrate preparation. Decerebellation did not significantly affect the baseline or the loaded values [tracheal occlusion (TO)] for respiratory duration, tidal volume, or magnitude of the integral of EMGdi response. Vagal blockade eliminated the load-compensating responses in the intact and the decerebrate preparation. However, vagal blockade in concert with decerebellation resulted in a significant (P < 0.05) reversible inhibition of the peak integral of EMGdi response during inspiratory TO. This suggests that removal of vagal and cerebellar influences during loaded breathing unmasked inhibitory inputs to the respiratory pattern generator. With vagus intact, decerebellation before or after decerebration abolished the attenuation of the peak integral of EMGdi response to TO observed with decerebration alone. We conclude that the cerebellum does play a role in determining the pattern of the respiratory response to TO. This influence may be direct and/or indirect via interaction with information emanating from suprapontine, vagal, and nonvagal sources.

In a previous study, we reported that inspiratory tracheal occlusion (TO) significantly inhibited the motor drive to the diaphragm in a decerebellated bilaterally vagotomized preparation (J. Appl. Physiol. 75:675-681, 1993). The hypothesis to be tested in the present study was that respiratory muscle afferents activated by inspiratory TO provided the inputs responsible for the observed inhibition. Adult cats were anesthetized, tracheotomized, and instrumented with diaphragm electromyographic (EMGdi) recording electrodes. The cerebellum, vagi, and dorsal spinal cord (C2-T2) were surgically exposed. Inspiratory TO was applied before and after cold blockade of the dorsal cord (C6) or dorsal root (C3-6) transection in the intact and decerebellated vagotomized cat. Respiratory timing (inspiratory and expiratory duration) was determined from the EMGdi record, and the peak integrated EMGdi (integral of EMGdi) response was used as an index of respiratory motor drive. Our results showed that 1) cold blockade at the dorsal C6 level in an intact preparation significantly increased the peak of the integral of EMGdi response to TO and was reversible upon rewarming; 2) as previously reported, decerebellation coupled with bilateral vagotomy significantly decreased the peak integral of EMGdi response to TO with no effect on timing; 3) cold blockade (-1 degree C) of the dorsal cord at C6 significantly attenuated this inhibition, and subsequent dorsal rhizotomy at C3-6 completely abolished this inhibition; and 4) decerebellation, cold blockade of the dorsal cord (C6), and dorsal rhizotomy (C3-6) did not significantly affect baseline values in bilaterally vagotomized cats.(ABSTRACT TRUNCATED AT 250 WORDS)

Previous studies suggest that afferents in the diaphragm participate in the reflex reduction in phrenic nerve efferent activation when the length of the diaphragm is increased by abdominal compression. The present study determined the response of tendon organ afferents in the diaphragm to increases in abdominal pressure. Five cats were anesthetized with thiopental sodium (60 mg/kg ip to induce, supplemented intravenously). Extracellular recordings from nine individual tendon organ afferents were made from right cervical dorsal root ganglia 5 and 6. Right crural electromyographic activity was recorded. The right extrathoracic phrenic nerve was isolated and stimulated to identify tendon organs on the basis of conduction velocity and response to twitch. The response to ramp-and-hold stretch of the diaphragm was used as an additional test to differentiate tendon organs from muscle spindles. The mean level of activity of the tendon organs during the 1st s of the inspiratory phase was 47 +/- 10 (SD) Hz. Abdominal compression was associated with a significant increase in the activity of these afferents to 61 +/- 11 Hz. Results indicate that increases in the activity of diaphragmatic tendon organs are associated with moderate increases in abdominal pressure and are likely the result of elevations in the active tension developed by the diaphragm. Combined with results from previous studies, it is possible that diaphragmatic tendon organs may play a role in the attenuation of respiratory muscle activation when abdominal pressure is increased.

This study examines the extent to which the cerebrum and other suprapontine structures modulate the respiratory response to added mechanical resistive loads to breathing. Nine adult cats were anesthetized with thiopental sodium, tracheotomized, and instrumented with diaphragm electromyographic (EMGdi) recording electrodes. Two levels of resistive loads and tracheal occlusion were applied at the onset of inspiration in random order before and after decerebration. The integrated signal of the EMGdi (integral of EMGdi) was used to detect changes in respiratory timing and as an index of respiratory motor drive. The results showed that, compared with intact cats, decerebration did not significantly change baseline values for peak integral of EMGdi, respiratory timing, systemic blood pressure, or arterial blood gases. Although the percent changes in the peak integral of EMGdi elicited by the added loads were still significantly greater than those elicited by unloaded control breaths after decerebration, the magnitude of the responses was significantly attenuated at all load levels compared with the intact preparation. It is concluded that the cerebrum and/or other suprapontine structures provide information that is facilitatory to the respiratory pattern generator with little effect on timing.