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PubMed2000

[Effects of muscle spindle afferents on the regulation of respiration in rabbit].

Effect of muscle spindle afferent invoked by intraarterial injection of succinylcholine (Sch) on respiration was assessed by changes in unit discharge of respiration related neurons and phrenic nerve of 63 anesthetized, bilaterally vagotomized and artificially ventilated rabbits. The results are as follows. (1) Intra~arterial injection of Sch prolonged inspiratory duration (Ti) or decreased expiratory duration (Te) and augmented respiratory frequency (RF). (2) 66% (37/56) of the medullary inspiratory neurons were excited and 10/17 of the expiratory neurons were inhibited by intraarterial injection of Sch, reaching maximum respectively at 1 2 and 2 3 min after injection, while non-respiration related neurons were not affected. (3) This effect of Sch was suppressed or abolished when muscle spindles were destroyed by intramuscular injection of bupivacaine.

Afferent Pathways↗
PubMed2002

A system for monitoring heart pulse, respiration and posture in bed.

A non-invasive system has been developed to monitor cardiac vibrations, respiration and posture of inbed hospitalized patients and elderly people who need constant care. These physiological variables are recorded by four 2 x 28 cm piezoelectric film acceleration sensors, eight 2 x 2 cm small pressure sensors and a 5 x 100 cm long pressure sensor. The piezoelectric sensors, attached to the chest over the heart during bed sleep or rest, detect the movements produced by the heartbeat and respiration. The eight small pressure sensors are attached at various positions on the upper and lower body. A longer pressure sensor, to detect the patient leaving the bed, is attached to the side of the bed. These sensor outputs are digitized at a sampling rate of 200 Hz using a 12-bit A/D converter and stored on a personal computer. The computer detects cardiac vibrations and respiration from upper chest movements and posture from the pressures recorded by small and long pressure sensors.

Bed Rest↗
PubMed1976

[External respiration and the functional state of the respiratory center in hypoxia developing against a background of inactivated carbonic anhydrase].

Experiments were conducted on cats; inactivation of carboanhydrase with diamox prevented developmento f hypocapnia and disturbances of the rhythmic activity of the respiratory neurons associated with it in acute hypoxia. However, comparision of electrophysiological data, external respiration indices, of the acid-base balance, pO2 and pCO2 of arterial blood demonstrated that, preventing development of pathological Cheyne-Stokes respiration under conditions of hypoxia, inactivation of carboanhydrase with diamox caused dissociation of the thoracic and abdominal respiration and dyspnea. The latter led to shifts in the metabolic processes and to disturbance of the electrolyte metabolism at the cell level.

Acetazolamide↗
PubMed2003

Coordination of suck-swallow and swallow respiration in preterm infants.

UNLABELLED: Safe oral feeding of infants necessitates the coordination of suck-swallow-breathe. Healthy full-term infants demonstrate such skills at birth. But, preterm infants are known to have difficulty in the transition from tube to oral feeding. AIM: To examine the relationship between suck and swallow and between swallow and breathe. It is hypothesized that greater milk transfer results from an increase in bolus size and/or swallowing frequency, and an improved swallow-breathe interaction. METHODS: Twelve healthy preterm (<30 wk of gestation) and 8 full-term infants were recruited. Sucking (suction and expression), swallowing, and respiration were recorded simultaneously when the preterm infants began oral feeding (i.e. taking 1-2 oral feedings/d) and at 6-8 oral feedings/d. The full-term infants were similarly monitored during their first and 2nd to 4th weeks. Rate of milk transfer (ml/min) was used as an index of oral feeding performance. Sucking and swallowing frequencies (#/min), average bolus size (ml), and suction amplitude (mmHg) were measured. RESULTS: The rate of milk transfer in the preterm infants increased over time and was correlated with average bolus size and swallowing frequency. Average bolus size was not correlated with swallowing frequency. Bolus size was correlated with suction amplitude, whereas the frequency of swallowing was correlated with sucking frequency. Preterm infants swallowed preferentially at different phases of respiration than those of their full-term counterparts. CONCLUSION: As feeding performance improved, sucking and swallowing frequency, bolus size, and suction amplitude increased. It is speculated that feeding difficulties in preterm infants are more likely to result from inappropriate swallow-respiration interfacing than suck-swallow interaction.

Bottle Feeding↗
PubMed1992

[Effects of injection of L-glutamate into the locus coeruleus complex area on the respiration].

Experiments were performed on 55 urethane anesthetized and flaxedil immobilized rabbits under artificial respiration. Injection of L-Glutamate into the locus coeruleus area led to a marked augmentation of respiration. This effect of L-Glutamate could be significantly attenuated or reversed by a previous injection of prazosin, yohimbine and propranolol into the NTS area. These results indicate that the neurons in the locus coeruleus are involved in the regulation of the respiration as a result of mediation by alpha and beta receptors in the NTS area.

Animals↗
PubMedDate not supplied

[Effects of temperature on respiration defensive behavior and locomotion of fresh water snail Lymnaea stagnalis].

Temperature dependence of lung respiration, defensive behavior and locomotion of Lymnaea stagnalis snail was studied. At the temperature in the range of 4-6 degrees C the rates of locomotion and respiration were reduced (as compared to control temperature of 14-16 degrees C), whereas defensive reactions were much more intense. Vice versa, the temperature rise to 24-26 degrees C activates respiration and locomotion but inhibits defensive behavior. It is suggested that the observed changes in Lymnaea behavior result from temperature-dependent reactions of neurons underlying these activities.

Animals↗
PubMedDate not supplied

Cheyne-Stokes respiration in congestive heart failure.

Cheyne-Stokes respiration is an abnormal breathing pattern which commonly occurs in patients with decompensated congestive heart failure and neurologic diseases, in whom periods of tachypnea and hyperpnea alternate with periods of apnea. In the majority of these patients, the ventilatory patterns may not be recognized, and the clinical features are generally dominated by the underlying disease process. Cheyne-Stokes respiration may, however, have profound effects on the cardiopulmonary system, causing oxygen desaturation, cardiac arrhythmias, and changes in mental status. Treatment of Cheyne-Stokes respiration in congestive heart failure with supplemental oxygen or nasal continuous positive airway pressure, in addition to conventional therapy, may improve the overall cardiac function and perhaps the patient's prognosis.

Cheyne-Stokes Respiration↗
PubMed2004

[Localization of ATPase activity, respiration and ultrastructure of wheat root cells with modulated ion conductivity of plasma membrane].

Changes in the localization of ATPase activity, respiration and ultrastructure of wheat root cells with modulated ion conductivity of plasma membrane were studied. A 2 h treatment of excised root with valinomycin (20 microM), N,N-dicyclohexylcarbodiimid (100 microM), gramicidin S (20 microM) and chlorpromazine (100 microM) caused an increased loss of potassium by cells, a decreased respiration and changes in the localization of ATPase activity and in cell ultrastructure. Differences in the observed changes may be conditioned by different mechanisms of action of the membrane active compounds used. It is concluded that changes in the localization of ATPase activity and ultrastructure may indicate some early specific responses of root cells, whereas the increase in the ion conductivity and decrease in respiration under disruption of ion homeostasis caused by membrane active compounds indicate unspecific responses of cells.

Adenosine Triphosphatases↗
PubMed1992

[The effects of the carbon dioxide pneumoperitoneum in laparoscopic cholecystectomy on postoperative spontaneous respiration].

Laparoscopic cholecystectomy (LSC) is being performed increasingly often. The carbon dioxide cavity increases end-expiratory carbon dioxide (exCO2), which can be regulated by mechanical ventilation. Because about 20-40% carbon dioxide remains in the patient at the end of surgery, we were interested in its influence on spontaneous respiration. PATIENTS AND METHODS. Fifteen patients classed as ASA 1-2 and undergoing LSC were compared with 15 patients (also ASA 1-2) undergoing laparotomy for cholecystectomy (LAP). All patients had balanced anaesthesia with fentanyl, enflurane, nitrous oxide and vecuronium. After surgery they were extubated when spontaneous respiration and vigilance were adequate. In the next 3 h we continuously determined exCO2 in the expired air through an intranasal catheter, and oxygen saturation (SAT), respiratory rate (RR) and heart rate (HR) using Oscar (Datex) and Ohmeda (Braun) apparatus while the patients were breathing room air. The blood pressure (BP) was determined intermittently. Postoperative pain treatment was standardized. RESULTS. The groups were reduced comparable with respect of the anthropometric data, because the weight was significantly higher in the LAP group. Fentanyl consumption was also significantly higher in the LAP group, reflecting the more pronounced trauma than with LSC. Mean exCO2 was 46 mmHg after LSC and 36 mmHg after LAP (P less than or equal to 0.05), continuously decreasing in the LSC group and increasing in the LAP group to 40 mmHg after 3 h. Mean RR was 18-20.min-1 after LSC and 12-15.min-1 after LAP during this period (P less than or equal to 0.05). There were no differences in SAT (94-96%), HR (75.min-1) and BP (130/80 mmHg). DISCUSSION AND CONCLUSIONS. The remaining carbon dioxide after LSC has important implications for postoperative spontaneous respiration. Probably due to an activation of carbon dioxide receptors, RR is increased to eliminate residual carbon dioxide. This is confirmed by a significantly increased exCO2 compared with that in the LAP group. This effect lasts at least 3 h, exCO2 being comparable in both groups, but RR is still increased after LSC. This different respiratory pattern does not affect SAT, being normal without hypoxic episodes. Cardiovascular parameters were also normal without group differences. We conclude that the carbon dioxide peritoneal cavity has important consequences for postoperative ventilation. Using our anaesthetic technique and postoperative treatment exCO2 reaches normal values after about 3 h due to an increased RR. If other methods, e.g., stronger opioids, which decrease carbon dioxide response are used, this effect may even be prolonged and more pronounced. We are now performing an investigation to evaluate this effect.

Adult↗
PubMed1992

[Development of a method of continuous monitoring of spontaneous respiration in the postoperative phase. 1. Normal values for cutaneous pO2- and pCO2-partial pressure together with pulse oximetry determined oxygen saturation in healthy young volunteers].

METHODS: Twenty-eight healthy volunteers of both sexes (14 male, 14 female, age 31 +/- 7 years, weight 70 +/- 12 kg) breathing room air were monitored for cutaneous partial pressures of oxygen and carbon dioxide (pctO2, pctCO2) and partial oxygen saturation (psO2) as determined by pulse oximetry. Data triplets were collected and stored by a personal computer at 30-s intervals during a 4-h resting period to establish a confidence range for the devices in use (TCM 3 with a combination electrode E 5270, and Pulse Oximeter, Radiometer). This data range was intended to be used in later noninvasive, continuous respiratory studies with postoperative patients. Means, standard deviations, and ranges were calculated for individual data and data pooled from 15-min intervals. Data distribution over time was calculated for 30-min intervals. RESULTS: Contrary to the saturation data delivered by pulse oximetry, the pctO2 and pctCO2 readings needed about 15 min to stabilize. The mean +/- SD of a total of 12,600 pctO2 measurements (77.2 +/- 10.9 mmHg) could not simply be compared with arterial normal values, whereas the pctCO2 measurements (39.9 +/- 3.6 mmHg) fit well with arterial data from the literature. Interestingly, pctCO2 values in unmedicated healthy adults were not uniformly distributed, suggesting individual differences in either skin permeability of central regulation of respiration. Additionally, the pctO2 readings were characterized by serious inter-subject variability, which confirms earlier studies that pctO2 is not suitable for routine monitoring procedures in adults, the mean +/- SD of a total of 4500 psO2 measurements was 94.9 +/- 1.6%. A statistically significant correlation was found between pctO2 and psO2 (r = 0.358). Cutaneous carbon dioxide readings of greater than 50 mmHg were observed in only 0.06% of all 12,600 data sets (maximum 51.3 mmHg; 28 volunteers), desaturations (less than 90%) in only 0.24% of all 4,500 saturation measurements (minimum 86%; 10 volunteers). DISCUSSION AND CONCLUSION: Monitoring of spontaneous respiration in the recovery room is regarded as essential to prevent serious complications resulting from surgery and anesthesia. This has become particularly true with newer analgesic techniques like spinal opiates or patient-controlled analgesia. Since minor degrees of opiate-induced respiratory depression are easily influenced by external stimulation, it is mandatory that any monitoring of spontaneous respiration must be nonstimulant, and prefereably noninvasive. The present communication is the first of a series of investigations to develop of monitoring technique for postoperative patients. Because normal values for the parameters studied are either lacking or dependent on the monitoring devices in use, the present paper defined the respective data ranges. It is concluded that pulse oximetry and pctCO2 measurement are both useful and sensitive for continuous, non-invasive respiratory monitoring in adults, whereas pctO2 measurements are of lesser value. Results in volunteers treated with opiates and postoperative patients under patient-controlled analgesia using the above mentioned equipment will be reported in following publications.

Adult↗
PubMed2005

Adenosine A1 receptors are involved in the modulation of the rhythmical respiration in neonatal rat brainstem slice in vitro.

This study was designed to investigate whether adenosine A1 receptors could modulate primary rhythmical respiration in mammals. Experiments were performed in in vitro brainstem slice preparations from neonatal rats. These preparations included the medial region of the nucleus retrofacialis (mNRF) with the hypoglossal nerve rootlets retained. The activity of the inspiration-related neurons (I neurons) in mNRF and respiratory rhythmical discharge activity (RRDA) of the hypoglossal nerve rootlets were simultaneously recorded by using microelectrodes and suction electrodes, respectively. Possible roles of adenosine A1 receptors in rhythmical respiration were investigated by administration of adenosine A1 receptor agonist R-phenylisopropyl-adenosine (R-PIA) and its specific antagonist 8-cyclopentyl-1,3- dipropylxanthine (DPCPX) into a modified Kreb's perfusion solution (MKS). DPCPX induced a significant decrease in the expiratory time and the respiratory cycles, and an increase in the discharge frequency and peak frequency of I neurons in the middle phase of inspiration. However, R-PIA significantly decreased the inspiratory time and integral amplitude as well as prolonged respiratory cycle. Moreover, the discharge frequency and the peak frequency of I neurons were decreased in the middle phase of inspiration, but not in the initial and terminal phases. The effect of R-PIA on rhythmical discharges could be partially reversed by additional application of DPCPX. These results indicate that adenosine A1-receptors are possibly involved in the modulation of rhythmical respiration through the inhibitory synaptic input from I neurons.

Animals↗
PubMed2005

[Effect of tetramethylpyrazine on the responses of respiration and expression of nNOS in brainstem to hypoxia in rats].

The aim of the present study was to investigate the effect of tetramethylpyrazine (TMP) on the changes of respiration and expression of neuronal nitric oxide synthase (nNOS) in brainstem induced by hypoxia in the rats. Hypoxia was induced by inhalation of 8% O2-balanced N2.The electromyogram (EMG) of diaphragm was monitored to evaluate the respiratory response of the rats to hypoxia. The immunohistochemical staining technique was used to study the change of the expression of nNOS in the brainstem during hypoxia. In the rats of hypoxia group, a successive process of response, excitatory followed by inhibitory, was produced. Twenty min after hypoxia, a significant inhibition of respiration occurred, which was characterized with a marked decrease in the inspiratory duration, the respiratory frequency, and the amplitude of inspiration and a prolongation of expiratory duration (P<0.05). In the rats of pretreated with TMP, the respiratory activity was not obviously depressed (P>0.05). In the rats of hypoxia group, the level of nNOS immunoreactivity was enhanced remarkably in the lateral reticular nucleus, nucleus of trapezoid, hypoglossal nucleus and the facial nucleus compared with the control group (P<0.05). In the rats of pretreated with TMP, the nNOS level increased further in the nuclei mentioned above (P<0.05). The results obtained indicate that TMP can reverse the inhibitory effect of hypoxia on respiration in the rats and that nNOS may be involved in the respiratory protective action of TMP.

Animals↗
PubMed2006

Notable Australian contributions to the management of ventilatory failure of acute poliomyelitis: with special reference to the Both respirator and Dr. John A. Forbes.

When Australia's 1937 epidemic of poliomyelitis created an urgent need for extra ventilating machines to compensate for respiratory paralysis, Edward Both, an innovative Adelaide biomedical engineer, invented a wooden-cabinet respirator capable of being made relatively quickly in sufficient quantity. His device, here called "the Both", alleviated the problem at Adelaide's Northfield Infectious Diseases Hospital and others, and in late 1938 was introduced into England when Both was visiting there. Appreciating its merits, Lord Nuffield financed assembly-line production at the Morris motor works in Cowley, Oxford. Then, through the Nuffield Department of Anaesthetics in Oxford's Radcliffe Infirmary, he had the Both distributed Commonwealth-wide, as a gift for treating ventilatory failure in polio - especially in children. For the 1937 epidemic in Victoria, and to the design of Melbourne University's Professor of Engineering, Aubrey Burstall, nearly 200 of another wooden-cabinet respirator were ultimately built. Some were installed at the Acute Respiratory Unit of the Infectious Diseases Hospital at Fairfield, then others "all over Australia". However, by the early 1950s, the Both had replaced Fairfield Hospital's "Burstall", which had functioned as Victoria's favoured respirator since 1937. Dr John Forbes at Fairfield became the foremost Australian clinician for expertise with the Both. Before the advent of intermittent positive pressure ventilation, the Both's usefulness had seen it tried for ventilatory failure in some non-polio conditions, but uptake of that application was limited. Nonetheless, Nuffield's philanthropy with the (Nuffield-)Both ultimately furthered progress along the 20th century pathway to intensive care medicine.

Acute Disease↗
PubMed1991

Observations on respiratory and cardiovascular rhythmicities during yogic high-frequency respiration.

Yogic high-frequency respiration--kapalabhati (KB)--was studied in 24 subjects from a point of rhythmicity. Respiratory movements, blood pressure and R-R intervals of ECG were recorded in parallel and evaluated by spectral analysis of time series. Respiratory signals during KB were modulated by 0.1 Hz rhythm in 82% of experiments. This component was also present in R-R intervals and blood pressure during KB. Frequency (0.2-0.3 Hz) was observed in 67% of respiratory records. The presence of the component 0.2-0.3 Hz in respiration was dependent on resting respiratory frequency. This frequency component was reduced in R-R intervals but increased in blood pressure during kapalabhati as compared to that at rest. The occurrence of both frequency components in respiration during KB supports the hypothesis about the integrative role of cardiovascular and respiratory rhythms in physiological states characterized by altered respiratory frequency.

Adult↗
PubMed1991

Effects of respiration on size and function of the athletic heart.

This study compares the effects of quiet breathing on the heart structure and function of pentathlon athletes (n = 11) and a less-conditioned control group (n = 12). Two-dimensional echocardiography was employed to direct an M-mode beam through the heart to minimize measurement errors due to respiratory motion of the heart. Respiration was simultaneously recorded with M-mode echocardiograms from a minimum of five respiratory and an average of 25 cardiac cycles. Athletes had greater (p less than 0.01) end-diastolic transverse dimensions (10%), and interventricular septal and left ventricular posterior wall thicknesses (25%). During inspiration right ventricular internal end-diastolic dimensions increased (8 vs 12%) and left ventricular end-diastolic dimension (LVIDd) decreased (7 vs 8%) in athletes and controls, respectively. Although significant reciprocal changes in LVIDd (p less than 0.01) occurred during respiration, no respiratory change was noted in the transverse diameter of the heart, interventricular septal, posterior wall thickness, LV end-systolic volume or ejection fraction. Inspiration caused a 21% fall (p less than 0.01) in LV stroke volume in both groups. Eighty-four to 92% of the inspiratory decrease in LV stroke volume in the subjects studied could be attributed to ventricular interdependence; no significant interaction was found between level of conditioning and respiration.

Echocardiography↗
PubMed1991

The effects of maxillary surgery on nasal respiration.

Le Fort I osteotomies frequently involve impaction of the maxilla into the nasal cavity, potentially affecting nasal form. It has been speculated that a concomitant change in nasal function may occur. The purpose of this study was to determine if there is an association between maxillary position and nasal function and to evaluate the influence of Le Fort I surgery on nasal function. Presurgical and postsurgical nasal resistance and percent nasal respiration were compared in 36 patients. Results indicated a mean change in nasal resistance 1 year after surgery, but mean percent nasal respiration did not change significantly. No prediction could be made for any patient relative to the effect of maxillary surgery on the nasal function parameters. No consistent association could be found between the amount or direction of maxillary surgical movement or the position of the maxilla and nasal respiration.

Adolescent↗
PubMed1990

[The study of effect of pain in the change of respiration by stimulating "renzhong" acupoint].

UNLABELLED: It had been reported that the stimulation of the "Renzhong" starts respiratory activity in rabbits whose respiration has been suspended. This action was caused by stimulating Renzhong. Those signals transmit to the nucleus of trigeminal spinal, and go to influence the nucleus of respiration. Those signals include of pain and other sense. This study investigated whether this stimulation of "Renzhong" is caused by pain or another stimulus. Phrenic nerve discharges and respiratory rates of 7 anesthetized rabbits, each weighing 1.5 to 2.0 kg were recorded. Stimulation of the "Renzhong" by electrical impulses (10 ms pulse, 20 Hz, 0.4-4 mA, duration 3-5 seconds). RESULTS: 1. Stimulating the "Renzhong", resulted in an 83 +/- 16% increase in the amplitude of phrenic nerve discharges, and a 31 +/- 6% decrease in respiratory rate. 2. morphine was then injected into the rabbits (5 mg/kg). After 8 minutes, the amplitude of phrenic nerve discharges had decreased by 22 +/- 9% and the respiratory rate had decreased by 16 +/- 6%. 3. At this acupoint, stimulation of the "Renzhong" resulted in a 43 +/- 8% increase of the amplitude of phrenic nerve discharges and a 20 +/- 6% decrease in respiratory rate. These results suggest that in the effect of the stimulation of "Renzhong" on the respiration pain sensation is one factor among the rest.

Acupuncture Points↗
PubMed1990

[Gas exchange and pulmonary hemodynamics in obese patients during epidural anesthesia and spontaneous respiration].

The function of external respiration, gas and ABB of blood, hemodynamics of the lesser circulation were studied during abdominal operations in patients with the IV degree obesity performed under conditions of epidural anesthesia with spontaneous respiration. On the basis of clinical and laboratory findings a conclusion was made on the adequacy of the method of epidural anesthesia with spontaneous respiration resulting in a considerably less amount of pulmonary complications.

Adult↗