Differences In Heart Rate Changes Research Articles

Analysis of Electrocardiogram Characteristics and its Influencing Factors in Thyroid Carcinoma

To investigate the characteristics and influencing factors of electrocardiogram changes in patients with thyroid cancer after operation. This study retrospectively analyzed the case data of 122 patients who underwent thyroid surgery for the first time in the department of breast and thyroid surgery from January 2020 to December 2021. All patients were pathologically confirmed to be papillary thyroid carcinoma. Firstly, the perioperative changes of electrocardiogram indexes were compared in all patients and then the influencing factors (age, sex, blood lipid level, body mass index and surgical method) of perioperative electrocardiogram changes were analyzed by univariate analysis. After operation, the serum thyroid stimulating hormone of all patients was higher and serum free triiodothyronine and free thyroxine were lower than that before operation (p<0.05). After operation, PR interval and QRS duration was shorter than before operation (p<0.05). The perioperative changes of heart rate were statistically significant in different age groups (p=0.043). The age group ≥55 y old had more obvious heart rate changes than the age group <55 y old. There was a difference in heart rate change between groups in different body mass index group (p=0.05). Perioperative free triiodothyronine was positively correlated with heart rate (r=0.476, p=0.004). The change of perioperative free thyroxine was negatively correlated with the change of PR interval duration (r=-0.411, p=0.016). The difference of perioperative corrected QT interval between male and female was statistically significant (p=0.027). There was a negative correlation between perioperative free thyroxine change and p wave change (r=-0.416, p=0.014). Age, gender and body mass index have a certain influence on the changes of perioperative electrocardiogram indicators. Postoperative cardiac function monitoring should be strengthened in elderly and obese patients. The change of thyroid hormone level is correlated with the change of perioperative electrocardiogram index. In the process of long-term thyroid stimulating hormone suppression treatment after operation, it can be tried to establish the sex-age related electrocardiogram standard of stratified thyroid hormone level.

Changes in heart rate during the peri-ictal period in focal epilepsy

We explored changes in heart rate during the peri-ictal period in patients with focal epilepsy, and differences in heart rate changes according to epileptic site and side were assessed. A total of 198 epileptic seizures in 102 patients with focal epilepsy, who had a definite epileptogenic focus and had undergone surgical treatment, were assessed from 2014 to 2019. Heart rate was measured manually during the peri-ictal period. Change in heart rate and the time it occurred were assessed and compared between different epileptic sites and sides. Heart rate increased in 177 (89.4%) of 198 seizures. In 82 (44.8%) of 183 seizures, the change in heart rate occurred before seizure onset. The median period of heart rate change was seven seconds (interquartile range: 3–11 seconds) in seizures with heart rate change before seizure onset. The number of seizures with heart rate increase before seizure onset was significantly greater for medial temporal lobe epilepsy compared to lateral temporal lobe epilepsy (p=0.019) and extratemporal lobe epilepsy (p=0.002). A change in heart rate prior to seizure onset is more likely to occur in patients with medial temporal lobe epilepsy, compared to those with lateral temporal lobe epilepsy and extratemporal lobe epilepsy. Patients with medial temporal lobe epilepsy may likely benefit from seizure warning and detection devices.

Cardiac activity in walleye (Sander vitreus) during exposure to and recovery from chemical anaesthesia, electroanaesthesia and electrostunning.

Handling and conducting invasive procedures are necessary for aspects of fisheries science, invariably inducing a stress response and imposing energetic demands on fish. Anaesthesia or immobilisation techniques are often used in an attempt to mitigate stress and improve welfare, yet these also come with their own impacts on post-release recovery. Here, the authors investigated whether changes in cardiac activity (heart rates over time, heart rate maxima, and scopes) differed in adult walleye (Sander vitreus) anaesthetised with AQUI-S® 20E (eugenol), electroanaesthetised with a transcutaneous electrical nerve stimulation (TENS) unit or electrostunned with a commercially developed stunning unit. This experiment was divided into two trials. In the first trial, fish were implanted with heart rate loggers and left to recover for c. 4 days. In the second trial, fish were implanted with heart rate loggers, given 3 days to recover and re-exposed to their initial treatments (excluding surgery). Post-treatment cardiac activity was quantified for both trials. Although highly variable across individuals, the authors found no significant differences in heart rate changes over time or recovery times among treatments. Maximum heart rates were consistent among treatment groups, yet significant differences in heart rate scope provided further evidence of strong interindividual variation in the second trial. Based on these results, the authors did not identify any welfare-relevant differences or concerns associated with one treatment over another. Further investigations of the relationships between measures of cardiac function and other physiological stress markers would be beneficial towards identifying best practices for fish handling in fisheries science.

Attentive immobility in the face of inevitable distal threat-Startle potentiation and fear bradycardia as an index of emotion and attention.

During fear conditioning, a cue (CS) signals an inevitable distal threat (US) and evokes a conditioned response that can be described as attentive immobility (freezing). The organism remains motionless and monitors the source of danger while startle responses are potentiated, indicating a state of defensive hypervigilance. Although in animals vagally mediated fear bradycardia is also reliably observed under such circumstances, results are mixed in human fear conditioning. Using a single-cue fear conditioning and extinction protocol, we tested cardiac reactivity and startle potentiation indexing low-level defensive strategies in a fear-conditioned (n=40; paired presentations of CS and US) compared with a non-conditioned control group (n=40; unpaired presentations of CS and US). Additionally, we assessed shock expectancy ratings on a trial-by-trial basis indexing declarative knowledge of the previous contingencies. Half of each group underwent extinction under sham or active transcutaneous vagus nerve stimulation (tVNS), serving as additional proof of concept. We found stronger cardiac deceleration during CS presentation in the fear learning relative to the control group. This learned fear bradycardia was positively correlated with conditioned startle potentiation but not with declarative knowledge of CS-US contingencies. TVNS abolished differences in heart rate changes between both groups and removed the significant correlation between late cardiac deceleration and startle potentiation in the fear learning group. Results suggest, fear-conditioned cues evoke attentive immobility in humans, characterized by cardiac deceleration and startle potentiation. Such defensive response pattern is elicited by cues predicting inevitable distal threat and resembles conditioned fear responses observed in rodents.

Effect of Virtual Reality Distraction on Pain and Anxiety in Children during Local Anesthesia

The purpose of this study was to evaluate the effect of virtual reality distraction on pain and anxiety in children during local anesthesia. Local anesthesia was administered to 3 groups: a control group without distraction, a group watching TV, and a group using a virtual reality device. The pulse rate and oxygen saturation rate were measured before and at the time of local anesthesia to assess the patients’ pain and anxiety, and the Wong-Baker Faces Pain Rating Scale was completed after local anesthesia. The group using the virtual reality device had a significantly lower heart rate change and lower Wong-Baker Faces Pain Rating Scale score than those in the control group and the group watching TV (&lt;i&gt;p&lt;/i&gt; &lt; 0.05). The greatest difference in heart rate change and Wong-Baker Faces Pain Rating Scale score, between the control and virtual reality distraction groups, was seen in 5 - 7-year-olds and a Frankl’s behavior rating scale grade of 3. The virtual reality device alleviated pain and reduced anxiety in children during local anesthesia.

Cardiac defensive reactions and orienting responses correspond to virtual withdrawal behavior choices in a virtual T-maze

Trait or stimulus valence related differences in heart rate change have often been investigated in psychophysiological research. However, the influence of different behavioral responses during motivational contexts on cardiac response patterns has been neglected so far. In this manuscript, HR change during movement via joystick during the negatively valent motivational condition of a virtual T-maze was investigated in two studies. Concerning the behavior, two specific avoidance response types could be identified in previous studies: a backwards withdrawal and an approach to safety. HR change and skin conductance response were hypothesized to be differentially related to these response patterns. For HR changes, the proposed difference was found. Participants facing the safety zone during their avoidance showed cardiac responses associated with the defensive response. In contrast, participants facing the negative entity of the virtual T-maze during their backwards withdrawal yielded cardiac responses associated with orienting reactions. Interestingly, these differences were found independently of the stimuli used in the two paradigms (monster vs. man). These findings lead to the conclusion that the execution of different behavioral responses during motivational conditions is an important factor in analyzing psychophysiological patterns, because they change according to the executed behavior and the linked visual and motivational properties.

Treatment of postoperative shivering after laparoscopic cholecystectomy under general anesthesia: a comparative clinical study

Background Postanesthesia shivering is one of the common harmful hazards following general anesthesia, especially with laparoscopic surgery. Postoperative shivering may lead to multiple complications, which may happen owing to increased oxygen demands, precipitating in cardiac and neurological ischemia. Aim This study aims to compare the therapeutic effects of pethidine, ondansetron, and ketamine in preventing postoperative shivering in laparoscopic cholecystectomy under general anesthesia. Patients and methods In this prospective study, patients aged from 26 to 55 years scheduled for elective laparoscopic cholecystectomy under general anesthesia were included. Patients who developed shivering in the recovery room were randomly divided into three groups: the first group [pethidine (P)] received intravenous pethidine (0.5 mg/kg), the second group [ondansetron (O)] received intravenous ondansetron 8 mg, and the third group [ketamine (K)] received intravenous ketamine (0.25 mg/kg). The frequency and degree of shivering was determined immediately after surgery, 15 min after study drugs administration, and 30 min after study drugs administration. Moreover, hemodynamic changes before and after drug administration and adverse effects of the study drugs were examined. Results A total of 95 patients who developed postoperative shivering after laparoscopic cholecystectomy were included in this study. No significant difference was found among the groups regarding treatment and grading of shivering in recovery room 15 min after the study drug administration. No significant difference was found among the groups regarding the recurrence of shivering in recovery room 30 min after study drug administration. There is a significant difference in heart rate changes among the three groups and between group K and group O at 10 and 20 min after the administration of study drugs (P 0.05). There was a significant difference among groups P, O, and K regarding sedation, hallucination, and nystagmus, being more in group K, but there was no difference among the groups regarding vomiting and itching. Conclusion The result of this study showed that ondansetron and ketamine effectively managed postoperative shivering with decreased incidence of recurrence of shivering. Ondansetron seems to be the drug to least affect hemodynamics, with less adverse effects than ketamine in comparison with pethidine.

The Effects of Arousal Regulation through Olfactory Inhalation on Static Stability and Heart Rate

Purpose: The purpose of this study was to analyze the changes in the center of pressure (COP) by arousal regulation during static stability control task using various olfactory stimulating inhalant (ammonia, lavender and citrus). Methods: 11 healthy male adults (Mage = 28.55 years, SD = ±3.67) were recruited for the study. A biometric shirt was utilized to measure the heart rate while force plate (AMTI force-platform) was used to determine changes in COP area. The tasks were differentiated based on visual and ground proprioception (eyes open or close & presence of absence of memory foam). Results: The results of this study were as follows. First, for ammonia inhalant condition, average COP area lower than control condition. EO, EOC conditions had statistically significant lower value. Second, for lavender inhalant condition, average COP area higher than control condition. EC condition had statistically significant higher value. Third, for citrus inhalant condition, average COP area lower than control condition. EO, EC, and EOM conditions had statistically significant lower value. Lastly, there was significant differences in heart rate change in lavender inhalant, only. Conclusion: This study implies that the arousal regulation through olfactory inhalant affects the level of static stability. These results suggest that arousal regulation through olfactory inhalant may affect task performance and may contribute to improvement in performance of athletes.

Comparison of time-domain, frequency-domain and non-linear analysis for distinguishing congestive heart failure patients from normal sinus rhythm subjects

Abstract It is known that patients with congestive heart failure have reduced ability to modulate heart rate in comparison with normal subjects. However, the characteristics of these changes is not well understood. This study therefore investigated the characteristic features of heart rate changes to assess how they differed between both groups. Fifty-two normal sinus rhythm subjects and 18 congestive heart failure patients from the PhysioNet database were studied. Nine common heart rate indices were studied: three time-domain indices (MEAN RR interval, standard deviation of successive RR SDNN, and square root of mean squared differences of successive RR RMSSD), three frequency-domain indices (normalized low-frequency power LFn, normalized high-frequency power HFn, and their ratio LF/HF), and three non-linear indices (vector length index VLI, vector angle index VAI and sample entropy SampEn). Two 5-min segments from every subject, neither of which had any ectopic beat, were analyzed. The statistical differences between the two clinical groups for the first and second segments, and their average were determined for all nine indices. Results showed that there was no significant difference between the two 5-min RR interval segments for any technique. All frequency-domain and non-linear indices, but only one time-domain index (SDNN), were significantly different between subject groups. However, some indices were much more sensitive to the clinical differences than others; with the best performing techniques, one non-linear index VLI and one time domain index SDNN, followed by all three frequency indices of LFn, HFn and LF/HF, and finally two of the other non-linear indices VAI and SampEn. A simple RBF SVM-based classification algorithm gave a good performance for classifying the CHF and NSR subjects. And the mean Se, Sp and Acc of SVM classifier from 10 folds were 91.31%, 90.04% and 90.95% respectively. We have shown that there are characteristic differences in heart rate changes between congestive heart failure and normal sinus rhythm, suggesting characteristic rhythm differences.

Is Spinal Anesthesia with Low Dose Lidocaine Better than Sevoflorane Anesthesia in Patients Undergoing Hip Fracture Surgery.

To evaluate general anesthesia with sevoflurane vs spinal anesthesia with low dose lidocaine 5% on hemodynamics changes in patients undergoing hip fracture surgery. In this randomized double blind trial 100 patients (50 patients in each group) older than 60 years under hip surgery were randomized in general anesthesia with sevoflurane and spinal anesthesia with lidocaine 5%. Hemodynamic changes including mean arterial pressure (MAP) and heart rate, blood loss, pain severity, nausea and vomiting and opioids consumption were compared in two groups. During surgery, difference between two groups regarding changes in mean arterial pressure was not significant, but the changes in heart rate were significantly different. Mean arterial pressure changes during recovery between two groups were significantly different. But there was no significant difference in heart rate changes. Bleeding in the sevoflurane group was significantly more than spinal group (513.ml vs. 365 ml). Moreover, AS Score, opioid consumption, and the nausea and vomiting in spinal anesthesia group was significantly lower than the sevoflurane group. We showed that general anesthesia with sevoflurane and spinal anesthesia with low dose lidocaine 5% have comparable effects on hemodynamics changes in patients undergoing hip fracture surgery. However postoperative pain score, vomiting and morphine consumption in patients with spinal anesthesia were lower than general anesthesia.

The Difference in Heart Rate Change between Temporal and Frontal Lobe Seizures during Peri-ictal Period.

Background and Purpose:Heart rate (HR) change is easily seen in seizures. Tachycardia is frequently seen in temporal lobe epilepsy (TLE), rather than extra temporal lobe epilepsy (XTLE). We report the difference in the HR pattern between TLE and frontal lobe epilepsy (FLE) during peri-ictal period.Methods:The ECG data, collected during EEG monitoring, was used. To compare the HR pattern between FLE and TLE, we investigated the baseline HR, maximum HR, seizure onset to peak HR, HR change, and the time return to baseline.Results:A total of 198 seizures (FLE was 115, TLE was 83) were included in this study. The baseline HR (in TLE, 74.9 ± 17.2 and in FLE, 70.7 ± 11.5 bpm), there was no difference between two groups. But the mean duration of the increased HR was more prolonged in TLE group (93.8 ± 54.9 seconds) than the FLE group(39.0 ± 21.4 seconds) (p < 0.001), the time to peak HR of the TLE group (135.1 ± 19.1 seconds) was higher than FLE group (119.3 ± 19.7 seconds) (p = 0.027), and the HR change of the TLE group (60.0 ± 26.3 bpm) was more prominent than that of the FLE group (22.8 ± 26.2 seconds) (p < 0.001). Furthermore, a longer duration of HR increase was seen in that of the TLE group than FLE group.Conclusions:The HR change of the TLE group was more prominent and prolonged than that of the FLE group. Therefore, the HR change can be a pattern that differentiates TLE from FLE.

Electrophysiological approaches to noise sensitivity

ABSTRACTBackground: Noise sensitivity describes an individual’s general reactivity to sound. It is a common trait found in many clinical populations and describes approximately 20% of the general population. Little is known about its underlying mechanisms, however. Objectives: Here we present findings from three studies designed to expose differences in electrophysiological measures between noise-sensitive and noise-resistant individuals. Method: Noise sensitivity was estimated using self-report measures, while electrophysiological indices included both cardiac (heart rate, heart rate variability) and electroencephalographic (event-related potential) measures. All three studies were designed with reference to preexisting theoretical frameworks. Results: Significant differences in heart rate change and heart rate variability indices between noise-sensitive and noise-resistant groups were found. Further, the noise-sensitive group exhibited less sensory gating than the noise-resistant group. Conclusions: While the findings from all three studies were not definitive in indicating a likely biological mechanism underlying noise sensitivity, they do suggest that electrophysiological investigation of noise sensitivity is viable and has potential to inform clinical research into a relatively understudied symptom.

Effects of β-Blockers With and Without Vasodilating Properties on Central Blood Pressure

β-Blockers are less effective than other antihypertensive drug classes in reducing central systolic blood pressure (cSBP) as compared with peripheral SBP (pSBP). Whether this effect is less pronounced with vasodilating β-blockers (VBB) when compared with nonvasodilating β-blockers (NVBB) remains unsettled. We conducted a systematic review and meta-analysis of randomized trials exploring the effects of β-blockers on both pSBP and cSBP in hypertension. We selected 20 studies, for a total of 32 treatment arms (n=21 for NVBB, n=11 for VBB) and 1263 participants (n=962 for NVBB, n=301 for VBB). pSBP decreased from 150 to 133 mm Hg for NVBB and from 145 to 134 mm Hg for VBB. cSBP decreased from 137 to 126 mm Hg for NVBB and from 132 to 123 mm Hg for VBB. SBP amplification (pSBP–cSBP) decreased significantly under VBB (−5.6 mm Hg; 95% confidence interval, −7.8, −3.4 mm Hg), but not under NVBB (−1.1 mm Hg; 95% confidence interval, −3.4, +1.2 mm Hg; P &lt;0.01 versus NVBB). There was high heterogeneity both within and between β-blockers subclasses. In a meta-regression model, the weighted difference in treatment-induced changes in SBP amplification between NVBB and VBB lost its significance after adjustment for mean age and baseline pSBP and heart rate (−2.9±2.3 mm Hg; P =0.22) and was almost abolished after adjustment for treatment-induced heart rate changes (−0.1±0.5 mm Hg; P =0.78). In conclusion, NVBBs, but not VBBs, determine a lower reduction in cSBP than in pSBP. However, the difference in treatment-induced SBP amplification changes between NVBB and VBB is nearly abolished after accounting for differences in heart rate changes.

Comparison of the effects of two different formulas of fluids in craniotomy patients.

Background:Intraoperative fluid management of the patients who had undergone neurosurgery presents special challenges for the anesthesiologist. In this study, we aimed to compare the effects of two fluid combinations (half-normal + bicarbonate with saline + Ringer's lactate) on brain relaxation, and acid, base, and hemodynamic balance in patients undergoing elective craniotomy surgery.Materials and Methods:This randomized double-blind controlled clinical trial study was done on 50 patients, of age 20–60 years, undergoing craniotomy in Alzahra Hospital in 2012. They were divided in two groups of 25 patients each. In the control group, after the patients received hypertonic saline, normal saline serum and Ringer's lactate was administered, and in the half-normal study group, 80 ml of sodium bicarbonate for every liter of it was added. Arterial blood gas (ABG) was taken before the last suture. Brain relaxation before dura opening was registered.Results:There was no significant difference in heart rate changes (P = 0.054). No significant difference was observed in the mean arterial pressure between the two groups (P = 0.99). Changes in pH, HCO3, and BE were not significantly different (P = 0.99) between the two groups. Urine output in half-normal saline group was significantly higher than in normal saline group. The mean bleeding volume was higher in normal saline group, but was not significantly different (P = 0.54). The mean volume of injected blood was higher in half-normal group with a significant difference (P = 0.54). The injected blood volume mean in half-normal group was higher with no significant difference (P = 0.55). The mean of brain relaxation was not different (P = 0.5).Conclusion:These two fluids did not show any significant differences in the studied variables in this research.

Effect of Rhythm on the Recovery From Intense Exercise

Motivational music (music that stimulates physical activity) was previously shown to enhance the recovery from intense exercise. The aim of the present study was to isolate the effect of rhythm (presumed to be the most effective factor of motivational music) on the recovery from intense exercise. Ten young adult active men (age: 26.1 ± 1.7 years) performed 6-minute run at peak oxygen consumption speed, at 3 separate visits (random order). At 1 visit, no music was played during the recovery after exercise. In the other visits, participants listened to motivational music that was previously shown to enhance recovery (a Western CD collection of greatest hits of all times converted to dance style, 140 b·min, strong bit, played by portable MP3 device using headphones at a volume of 70 dB) or only to the rhythm beats derived from the same songs. Mean heart rate (HR), rating of perceived exertion (RPE), number of steps (measured by step counter) and blood lactate concentrations were determined at 3, 6, 9, 12, and 15 minutes of the recovery. There was no difference in HR changes during the recovery at all conditions. Compared with the recovery without music, listening to motivational music during recovery was associated with significant greater number of steps, lower absolute lactate levels, and greater mean decrease of RPE. Listening only to rhythm beats, derived from the same music, during the recovery was associated with significant greater number of steps and lower absolute lactate levels compared to recovery without music. Music was significantly more effective than rhythm only in the absolute mean number of steps. The beneficial effect of both music and rhythm was greater toward the end of the recovery period. Results suggest that listening to music during nonstructured recovery can be used by professional athletes to enhance recovery from intense exercise. Rhythm plays a very important role in the effect of music on recovery and can be used to enhance nonstructured recovery when music is unavailable or when cultural barriers and individual music preferences may apply. The optimal music and rhythm selection is yet to be determined.

1454 Impact of a Cham Jam Intervention on Physical Fitness in Elementary School Students

Background and AimsCHAM JAM, a classroom-based physical activity intervention, has been effective in increasing physical activity levels in elementary school students. The objective if this study was to determine the...

Activation During Observed Parent-Child Interactions with Anxious Youths: A Pilot Study.

Parent–child interaction paradigms are often used to observe dysfunctional family processes; however, the influence of such tasks on a participant’s level of activation remain unclear. The aim of this pilot project is to explore the stimulus value of interaction paradigms that have been commonly used in child anxiety research. Twenty-nine parent–child dyads with clinically anxious (n = 16) and non-anxious (n = 13) youths engaged in a series of tasks (threat and non-threat) used in previous studies of parenting and youth anxiety. Heart rate (HR) data, as an indicator of physiological activation, were collected across tasks, and participants rated the perceived representativeness of their interactions in the laboratory to their usual behavior at home. Significant HR changes were observed for both parent and child. Change in child HR from baseline to non-threat task was smaller than change in HR from baseline to threat tasks. Change in parent HR from baseline to ambiguous situations tasks was smaller than changes from baseline to other threat tasks. Differences in HR change between anxious and non-anxious children were explored. Participants rated laboratory interactions as similar to those experienced in the home. Results suggest that presumably emotionally-charged discussion tasks may produce increased activation compared to tasks that were designed to be more neutral. Implications for future research and limitations are discussed.

Arterial Blood Pressure and Heart Rate Response to Lightwand or Direct Laryngoscopy for Endotracheal Intubation

Background: Tracheal intubation commonly results in sympathetic stimulation manifested by increased heart rate and arterial blood pressure. This study was carried out to determine whether lightwand would result in less hemodynamic changes than direct laryngoscopy. Methods: With informed consent, fourty healthy female patients scheduled of elective surgical procedures were randomly allocated into two groups; lightwand(LW) or direct laryngoscopy(DL) group. Mean arterial pressure(MAP) and heart rate(HR) were recorded upon arrival. Under a standardized anesthetic technique, the patients were intubated either with no. 3 curved blade direct laryngoscopy(DL group) or with lightwand(LW group). The MAP and HR were recorded before intubation and every 1 minutes following intubaion. Time to intubation(TTI) was also recorded. All patients were intubated by a same fourth grade resident. Results: Fourty patients were studied. Every intubation was successed in first attempt. The TTI was significantly shorter in LW group. Even while there was no significant difference in HR changes, there was significant difference in the increase of MAP following intubation. The increase of MAP was significantly greater with DL than with LW. Conclusions: This study suggests that lightwand intubation requires shorter TTI and may give rise to less blood pressure change than direct laryngoscopy. So we found no difference in disadvantage and may offers advantage in terms of hemodynamic stability.(Korean J Anesthesiol 1997; 33: 858∼863)

A prospective randomized clinical trial comparing two oxytocin induction protocols

Our objective was to compare the safety and efficacy of two accepted oxytocin induction protocols that differ in oxytocin dose increments. At the Carolinas Medical Center in Charlotte, North Carolina, 151 women with indications for induction of labor were prospectively randomized into one of two oxytocin induction protocols. Safety and efficacy of the two protocols were analyzed with two-tailed t tests and chi 2. Time from induction to establishment of a regular labor pattern was significantly shorter in the experimental group compared with the traditional group (p = 0.03). However, no significant difference was seen from onset of induction to time of delivery. Incidences of hyperstimulation were not significantly different between the two protocols, but there was a trend toward a higher incidence of fetal heart rate changes in the experimental group (p = 0.08). These data suggest that induction with larger dose increments will shorten time to adequate labor without an associated increase in uterine hyperstimulation or poor neonatal outcome. The differences in heart rate changes are concerning and merit further investigation. If confirmed by further studies, an increased risk of cord compression could outweigh the benefit of a faster onset of contractions.

Pulmonary Function in the Elderly: Response to Theophylline Bronchodilation

This clinical investigation was designed to characterize the pharmacologic response to theophylline in elderly individuals. Incremental theophylline plasma concentrations (0, 5, 10, 15, and 20 mcg/mL), achieved through dose escalation of intravenous aminophylline, were correlated with pulmonary airway responses in ten young and ten elderly male asthmatic volunteers. The older group had lower baseline pulmonary function values, suggestive of a greater degree of baseline airways obstruction. Despite wide intersubject variability, the elderly subjects demonstrated a lower absolute change in bronchodilator response to equal concentrations of theophylline than did their younger counterparts (P less than .05). A progressive increase in heart rate was noted with increasing theophylline concentrations, but no significant difference in heart rate change between groups was detected (P greater than .05). Whether the difference in theophylline induced bronchodilator response observed in the young and elderly groups is due to a difference in age or in severity of airway obstruction is yet unknown.