Biomedical subjects

O J Polo

Publications and source records attributed to O J Polo.

4 recordsLinked to original sources

PubMed1996

Hypercapnic blood pressure response is greater during the luteal phase of the menstrual cycle.

We investigated the cardiovascular responses to acute hypercapnia during the menstrual cycle. Eleven female subjects with regular menstrual cycles performed hypercapnic rebreathing tests during the follicular and luteal phases of their menstrual cycles. Ventilatory and cardiovascular variables were recorded breath by breath. Serum progesterone and estradiol were measured on each occasion. Serum progesterone was higher during the luteal [50.4 +/- 9.6 (SE) nmol/l] than during the follicular phase (2.1 +/- 0.7 nmol/l; P < 0.001), but serum estradiol did not differ (follicular phase, 324 +/- 101 pmol/l; luteal phase, 162 +/- 71 pmol/l; P = 0.61). The systolic blood pressure responses during hypercapnia were 2.0 +/- 0.3 and 4.0 +/- 0.5 mmHg/Torr (1 Torr = 1 mmHg rise in end-tidal PCO2) during the follicular and luteal phases, respectively, of the menstrual cycle (P < 0.01). The diastolic blood pressure responses were 1.1 +/- 0.2 and 2.1 +/- 0.3 mmHg/Torr during the follicular and luteal phases, respectively (P < 0.002). Heart rate responses did not differ during the luteal (1.7 +/- 0.3 beats.min-1.Torr-1) and follicular phases (1.4 +/- 0.3 beats.min-1.Torr-1; P = 0.59). These data demonstrate a greater pressor response during the luteal phase of the menstrual cycle that may be related to higher serum progesterone concentrations.

Adult↗

PubMed1994

Mandibular advancement with dental appliances in obstructive sleep apnoea.

The purpose of this study was to compare the effects of a modified Herbst appliance (mHA) and a muscle relaxation appliance (MR) on nocturnal breathing and body movement activity in patients with obstructive sleep apnoea syndrome (OSAS). To increase the airway space posterior to the tongue base without severely affecting the craniomandibular joint, the mHA was adjusted to anchor the mandible at 50% of maximum protrusion. MR producing an occlusal coverage but no protrusion served as a control appliance. All-night static charge-sensitive bed (SCSB) and finger oximeter recordings were done to six male patients in three conditions: first without dental device and then with mHA and with MR, in a random order, after a 2 month period of habituation. The oxyhaemoglobin desaturation events were 44.7 h-1 of recording observed during the control night, 29.6 h-1 with mHA (P = 0.087). The frequency of body movements decreased from 34.9 to 20.4 h-1 (P = 0.0079), respectively. MR had no significant effects either on the frequency of the desaturation events or the frequency of body movements, but the increased respiratory resistance breathing, indicating presence of partial upper airway obstruction, was reduced from 14.3 to 6.9% of the time in bed (P = 0.022). We conclude that 50% protrusion chosen for these experiments, produced with a mHA, brought about some alleviation of upper airway obstruction in our preselected patients, but did not lead to sufficient control of apnoea. The reduction of partial upper airway obstruction induced with a MR warrants further studies in a larger patient population.

Adult↗

PubMed1992

Sleep movements in teethgrinders.

To investigate the nocturnal motor activity associated with teethgrinding, 12 patients and 12 controls were recorded during sleep with the masseter muscle electromyogram (EMG) and the static charge-sensitive bed movement sensor. The frequency of body movements per hour was 21.4 in the teethgrinders and 14.0 (P less than .05) in the control group. The movement time was 87.4 seconds per hour in the teethgrinders and 55.2 seconds per hour (P less than .01) in the controls. The differences were most obvious in the body movements with temporal association to EMG elevation during the first stage of sleep. The number of isolated EMG elevations showed great interindividual variation and did not differ between groups. The teethgrinders complained more frequently of delayed sleep onset and daytime tiredness. The data suggest that the motor disturbance of teethgrinding is not limited to masticatory muscles but is manifested also as increased general body movement activity.

Adult↗

PubMed1991

Why don't all heavy snorers have obstructive sleep apnea?

Patients with obstructive sleep apnea (OSA) and heavy snorers without apnea both show intrathoracic suction pressures during sleep that exceed their static upper airway closing pressures. Complete airway occlusion, however, occurs only in the former patient group. We hypothesized that the kinetic properties of the airflow would be different in these two types of patients because of differences in upper airway morphology. The pharyngeal computed tomography (CT) was used to measure the cross-sectional areas of the upper airways in 15 patients with OSA, 25 nonapneic heavy snorers, and 14 control subjects while they were awake. Nocturnal breathing was monitored with the static charge-sensitive bed (SCSB). The patients with OSA had a narrower airspace at the velopharyngeal (VP) level than the controls (p less than 0.01); the nonapneic snorers did not differ from the other groups. At the tongue base (TB) and the hyoid bone (HB) levels there was no difference between the OSA and the control groups, but the nonapneic snorers had narrower airways at both of these levels compared with control subjects (p less than 0.01) and at the hyoid bone level compared with the OSA group (p less than 0.05). The VP/HB ratio was the parameter that best distinguished the patients with OSA from the nonapneic snorers (lower in the OSA group, p less than 0.001). We suggest that airway collapse during sleep is favored by a narrow velopharynx associated with large hypopharynx. Some heavy snorers may not have an oropharyngeal collapse because the peak inspiratory suction pressure could already be damped down at the level of the relatively narrow hypopharyngeal airways.

Airway Resistance↗