Types Of Breathing Patterns Research Articles

Noninvasive Clean Room Free Printed Piezoresistive Breath Sensor for Point of Care Application

Respiratory rate and pattern evaluation are vital parameters for clinical examination and overall assessment of the health status of an individual. Wearable and flexible real-time breath monitoring sensors are promising and advantageous tools that can help in early and quick diagnosis. This work is a single-step cost-effective, stretchable, and comfortable breath sensor with easy fabrication. The developed Laser-Induced Graphene (LIG)-based Wearable Sensor (LIG-WS) is a kirigami-structured piezoresistive-based respiratory sensor for evaluating variations in breathing patterns. This sensor utilizes the hygroscopic nature of LIG to analyze the breathing pattern and the respiratory rate. The flexible breath sensor can be attached to a surgical mask, helping to recognize various diseases, including sleep apnea, asthma, and cardiac arrest. The fabricated sensor has been tested for sensing different types of breathing patterns, such as usual, slow, shallow, and labored. A quick response time of 2.2 s is observed, and the sensitivity has been analyzed at different humidity, temperature, and touch responses. The stability of the sensor is evaluated over 30 days which demonstrated appreciable stability. The sensor has relevance in wearable breath monitoring and medical diagnostics.

Machine diagnosis of chronic obstructive pulmonary disease using a novel fast-response capnometer

BackgroundAlthough currently most widely used in mechanical ventilation and cardiopulmonary resuscitation, features of the carbon dioxide (CO2) waveform produced through capnometry have been shown to correlate with V/Q mismatch, dead space volume, type of breathing pattern, and small airway obstruction. This study applied feature engineering and machine learning techniques to capnography data collected by the N-Tidal™ device across four clinical studies to build a classifier that could distinguish CO2 recordings (capnograms) of patients with COPD from those without COPD.MethodsCapnography data from four longitudinal observational studies (CBRS, GBRS, CBRS2 and ABRS) was analysed from 295 patients, generating a total of 88,186 capnograms. CO2 sensor data was processed using TidalSense’s regulated cloud platform, performing real-time geometric analysis on CO2 waveforms to generate 82 physiologic features per capnogram. These features were used to train machine learning classifiers to discriminate COPD from ‘non-COPD’ (a group that included healthy participants and those with other cardiorespiratory conditions); model performance was validated on independent test sets.ResultsThe best machine learning model (XGBoost) performance provided a class-balanced AUROC of 0.985 ± 0.013, positive predictive value (PPV) of 0.914 ± 0.039 and sensitivity of 0.915 ± 0.066 for a diagnosis of COPD. The waveform features that are most important for driving classification are related to the alpha angle and expiratory plateau regions. These features correlated with spirometry readings, supporting their proposed properties as markers of COPD.ConclusionThe N-Tidal™ device can be used to accurately diagnose COPD in near-real-time, lending support to future use in a clinical setting.Trial registration: Please see NCT03615365, NCT02814253, NCT04504838 and NCT03356288.

Analysis of Breathing Patterns from Thermal Images Using an Automated Segmentation Method

Breathing is one of the important vital signs in diagnosing and monitoring for patients’ treatment and disease. Few modalities have been used to evaluate breathing activity such as respiratory belt, thermistor and capacitive sensor. However, these requires external attachments such as electrode or sensor which might be inconvenience over long period of time. Hence, we proposed the use of thermography as a contactless monitoring device. In this study, inspiration time and expiration time of three different breathing patterns such as normal, prolonged and rapid breathing patterns were measured by using the thermography. Thermal images obtained from the subjects were processed and analysed by using an automated segmentation method which integrate the knowledge of edge-based and region-based segmentation methods into the algorithm developed. The algorithm developed in this study has shown that the tracker was able to segment the region of interest of the thermal images automatically and it provides a more accurate and stable results than manual calculation method. Thus, three different types of breathing patterns could be identified based on the inspiration time to expiration time ratio. Results shows that there was less than 5% of relative error which suggest the benefit of this algorithm.

Dosimetric Evaluation of Amplitude-based Respiratory Gating for Delivery of Volumetric Modulated Arc Therapy

The purpose of this study is to perform a dosimetric evaluation of amplitude-based respiratory gating for the delivery of volumetric modulated arc therapy (VMAT). We selected two types of breathing patterns, subjectively among patients with respiratory-gated treatment log files. For patients that showed consistent breathing patterns (CBP) relative to the 4D CT respiration patterns, the variability of the breath-holding position during treatment was observed within the thresholds. However, patients with inconsistent breathing patterns (IBP) show differences relative to those with CBP. The relative isodose distribution was evaluated using an EBT3 film by comparing gated delivery to static delivery, and an absolute dose measurement was performed with a 0.6 cm3 Farmer-type ion chamber. The passing rate percentages under the 3%/3 mm gamma analysis for Patients 1, 2 and 3 were respectively 93.18%, 91.16%, and 95.46% for CBP, and 66.77%, 48.79%, and 40.36% for IBP. Under the more stringent criteria of 2%/2 mm, passing rates for Patients 1, 2 and 3 were respectively 73.05%, 67.14%, and 86.85% for CBP, and 46.53%, 32.73%, and 36.51% for IBP. The ion chamber measurements were within 3.5%, on average, of those calculated by the TPS and within 2.0%, on average, when compared to the static-point dose measurements for all cases of CBP. Inconsistent breathing patterns between 4D CT simulation and treatment may cause considerable dosimetric differences. Therefore, patient training is important to maintain consistent breathing amplitude during CT scan acquisition and treatment delivery.

Electromyographic study on the sternocleidomastoid and pectoralis major muscles during respiratory activity in humans

Abstract Introduction: This study aimed to evaluate the simultaneous and maximum activities ofthe sternocleidomastoid (SCM) and pectoralis major (PM) muscles, to determine how the two types of breathing patterns (normal and forced) can affect these activities , and to verify which of these muscles could be used to establish an evaluation protocol for patients undergoing mechanical ventilation. Methods: Eleven healthy men, aged 18 to 25 years, participated in this study. The individuals remained in supine position using a respiratory belt to monitor both inspiratory and expiratory phase during shifts in the rib cage, performing three repetitions for the normal and forced respiratory movements, while keeping the breathing rhythm with a standard metronome. Electromyographic signals were captured using bipolar surface electrodes placed on the lower third of the SCM muscle and on the lower PM muscle fibers. Electromyographic signals were analyzed and the root mean square (RMS) values were calculated for a complete respiratory cycle. The EMG values were analyzed using the Bonferroni test for multiple comparisons. The homogeneity of variances was verified using the logarithmic transformation (LOG). The level of statistical significance was set at 5% (SPSS 19.0). Results: The values showed that there are signiicant differences between the EMG values of the SCM muscle during normal and forced respiration and the EMG values of the ECM and PM muscles during forced respiration. Conclusion: These results showed that the SCM muscle can be an indicator for the development of parameters to be used in the analysis of patients with respiratory failure.

Catathrenia (nocturnal groaning): an abnormal respiratory pattern during sleep

Catathrenia (nocturnal groaning) is a rare condition characterized by monotonous irregular groans occurring during sleep. Ten patients (five women; mean age: 27 +/- 7.4 years, range: 15-41) with sleep-related groaning persisting for years or decades and normal daytime fibreoptic laryngoscopy and respiratory function tests underwent videopolysomnographic recording (VPSG) analysing their respiratory patterns during sleep. After the VPSG, all patients were clinically followed up for a mean period of 4.9 +/- 3.5 years. On VPSG, all patients showed nocturnal groaning during NREM sleep and particularly during REM sleep stages. Groaning was associated with disproportionate prolonged expiration causing reduced breathing rate without oxygen desaturation. The breathing pattern with prolonged expiration and sound production alternated with a normal respiratory pattern without groaning. Endoesophageal pressure during groaning showed mildly positive swings at the initial phase of expiration suggesting a partial mild expiratory upper airway obstruction. At the end of the follow-up period, all patients reported persistent nocturnal groaning but no other clinical manifestations. Groaning confined to sleep alternating with normal breathing and the absence of long-term clinical consequences suggest that catathrenia is because of an abnormality of the internal respiratory drive system, possibly related to persistence of a neonatal (vestigial) type of breathing pattern.

Effect of Body Size on Breathing Pattern and Fine-Particle Deposition in Children

Bennett WD, Zeman KL. J Appl Physiol. 2004;97:821–826The fractional deposition (DF) of fine particles was measured in the lower airways of healthy children during their resting breathing pattern to allow for additional investigation of the epidemiologic link between airborne particulates and respiratory morbidity in children.The study included 36 children, aged 6 to 13 years, with no acute respiratory infections within the past 4 weeks or previous history of lung disease.To avoid the higher minute ventilation induced in children by breathing on a mouthpiece, resting breathing pattern was measured by respiratory inductance plethysmography using elastic inductance bands around the chest and abdomen with expansion and contraction calibrated to spirometry. The DF of 2-μm carnauba wax aerosol was then measured by using light-scattering photometry at the mouth, with the child breathing according to their previously determined resting breathing pattern. The numbers of inhaled and expired particles were calculated as a function of the inspiratory and expiratory times, tidal flow, and particle concentrations, and the DF was reported as the proportion of particles not expired. The rate of particle deposition (Drate) was a function of the DF and the minute ventilation.There was good correlation between resting breathing pattern measured by respiratory inductance plethysmography and the breathing pattern measured during DF ascertainment. The mean DF was 0.22 ± 0.10, similar to resting DF measured in adults in previous studies. Tidal volume was the best predictor of DF (r = 0.79; P < .001), and DF was also correlated with body mass index (BMI) (r = 0.47; P = .004). Children with a BMI in the >95th percentile had nearly twice the DF of those with a BMI in the <25th percentile (0.28 ± 0.13 vs 0.15 ± 0.06; P < .02). Resting minute ventilation was also higher in the overweight children (8.5 ± 2.2 vs 5.9 ± 1.1 L/min; P < .01). Drate was correlated with BMI (r = 0.46; P = .004) and was 2.8 times higher in children with a BMI in the >95th percentile compared with those with a BMI in the <25th percentile (P < .02).Children with higher BMIs may be at greater risk of respiratory morbidity associated with inhalation of airborne fine-particulate matter.A focus of this study was the determination of resting particle deposition; however, the higher minute ventilation seen with traditional mouthpiece breathing in children may be a closer approximation of how a child would breathe during activity. Assessment of fine-particle deposition during both types of breathing patterns may provide useful information. The higher resting rate of 2-μm particle deposition in children with elevated BMIs suggests that fine particulates may make a greater contribution to respiratory morbidity in obese children, possibly contributing to the association between obesity and the incidence of asthma symptoms. Additional study of a larger number of children, including those with a BMI of >30, would be helpful to confirm these findings.

Vital signs

Background Vital signs traditionally consist of blood pressure, temperature, pulse rate and respiratory rate, and are an important component of monitoring the patient's progress during hospitalisation. An initial search of the literature indicated that there was a vast volume of published information relating to this topic; however, there had been no previous attempt to systematically review this literature. This review was therefore initiated to identify, appraise and summarise the best available evidence relating to the measurement of vital signs in hospital patients. Objectives The objectives of this review were to present the best available information related to the monitoring of patient vital signs with regard to their purpose, limitations, optimal frequency of measurements, and what measures should constitute vital signs. The review also sought to identify additional issues of importance related to the individual parameters of temperature measurement, blood pressure assessment, pulse rate measurement and respiratory rate measurement. Review methods This review considered all studies that related to the objectives and included neonatal, paediatric and/or adult hospital patients. The outcome measures of interest were those related to the accuracy of, required frequency of or the need for vital signs. The review also considered any study addressing some aspect of vital signs measurement to ensure all issues of importance were identified. The search sought to find both published and unpublished studies. Databases searched included CINAHL, Medline, Current Contents, Cochrane Library, Embase and Dissertation Abstracts. The references of all identified studies were examined for additional references. All studies were checked for methodological quality, and data was extracted using a data extraction tool. Results Although a variety of measures may be useful additions to the traditional four vital sign parameters, only pulse oximetry and smoking status have been shown to change patient care and outcomes. There are suggestions that vital sign monitoring has become a routine procedure, but little useful information was identified in regard to the optimal frequency of vital sign measurement. It was noted that many of the important issues related to vital sign measurement have not been investigated through research. There is currently only limited research related to respiratory rate as a vital sign; however, its value as an indicator of serious illness has not been reliably established. There is only limited research relating to pulse rate measurements. Although routinely used for all hospital patients, the ability to detect serious physiological changes by assessment of pulse rate has not been rigorously evaluated. Many factors were identified that could potentially influence the accuracy of blood pressure measurement. Auscultation is accurate for the measurement of systolic blood pressure using phase I Korotkoff sound as the reference point, and for diastolic pressure if phase V Korotkoff sounds are used. Cuff size can influence accuracy, in that using a cuff that is too narrow will likely overestimate blood pressure and a cuff that is too wide will underestimate the pressure. Research suggests that blood pressure should be measured on the upper arm, while the arm is resting at approximate heart level. Studies have shown that healthcare workers often measure blood pressure in an incorrect and inaccurate way, and this is of some concern. However, a small number of studies suggest that education programs can be effective in improving blood pressure measurement techniques. The largest volume of research identified during this review related to the measurement of temperature. For accurate measurement of oral temperatures the thermometer should be positioned in either the left or right posterior sublingual pocket and remain in the mouth for 6–7 min. Although oxygen therapy and different types of breathing patterns will not influence accuracy of oral temperature measurements, hot or cold liquids will. For the measurement of tympanic temperatures, an ear tug should be used to help straighten the external auditory canal and so ensure measurement accuracy. The presence of impacted cerumen will likely result in inaccurate measurements. The only potential harm as a result of measuring vital signs was associated with glass mercury thermometers, in terms of rectal perforation, the risk of mercury poisoning was not clearly established. Conclusions Although there has been considerable research undertaken on many specific aspects of vital sign measurement, there is an urgent need for further primary research into the more general issues such as what parameters should be measured, the optimal frequency of measurements and the role of new technology in patient monitoring.

Vital signs

Executive summaryBackground Vital signs traditionally consist of blood pressure, temperature, pulse rate and respiratory rate, and are an important component of monitoring the patient’s progress during hospitalisation. An initial search of the literature indicated that there was a vast volume of published information relating to this topic; however, there had been no previous attempt to systematically review this literature. This review was therefore initiated to identify, appraise and summarise the best available evidence relating to the measurement of vital signs in hospital patients.Objectives The objectives of this review were to present the best available information related to the monitoring of patient vital signs with regard to their purpose, limitations, optimal frequency of measurements, and what measures should constitute vital signs. The review also sought to identify additional issues of importance related to the individual parameters of temperature measurement, blood pressure assessment, pulse rate measurement and respiratory rate measurement.Review methods This review considered all studies that related to the objectives and included neonatal, paediatric and/or adult hospital patients. The outcome measures of interest were those related to the accuracy of, required frequency of or the need for vital signs. The review also considered any study addressing some aspect of vital signs measurement to ensure all issues of importance were identified. The search sought to find both published and unpublished studies. Databases searched included CINAHL, Medline, Current Contents, Cochrane Library, Embase and Dissertation Abstracts. The references of all identified studies were examined for additional references. All studies were checked for methodological quality, and data was extracted using a data extraction tool.Results Although a variety of measures may be useful additions to the traditional four vital sign parameters, only pulse oximetry and smoking status have been shown to change patient care and outcomes. There are suggestions that vital sign monitoring has become a routine procedure, but little useful information was identified in regard to the optimal frequency of vital sign measurement. It was noted that many of the important issues related to vital sign measurement have not been investigated through research.There is currently only limited research related to respiratory rate as a vital sign; however, its value as an indicator of serious illness has not been reliably established. There is only limited research relating to pulse rate measurements. Although routinely used for all hospital patients, the ability to detect serious physiological changes by assessment of pulse rate has not been rigorously evaluated. Many factors were identified that could potentially influence the accuracy of blood pressure measurement. Auscultation is accurate for the measurement of systolic blood pressure using phase I Korotkoff sound as the reference point, and for diastolic pressure if phase V Korotkoff sounds are used. Cuff size can influence accuracy, in that using a cuff that is too narrow will likely overestimate blood pressure and a cuff that is too wide will underestimate the pressure. Research suggests that blood pressure should be measured on the upper arm, while the arm is resting at approximate heart level. Studies have shown that healthcare workers often measure blood pressure in an incorrect and inaccurate way, and this is of some concern. However, a small number of studies suggest that education programs can be effective in improving blood pressure measurement techniques. The largest volume of research identified during this review related to the measurement of temperature. For accurate measurement of oral temperatures the thermometer should be positioned in either the left or right posterior sublingual pocket and remain in the mouth for 6–7 min. Although oxygen therapy and different types of breathing patterns will not influence accuracy of oral temperature measurements, hot or cold liquids will. For the measurement of tympanic temperatures, an ear tug should be used to help straighten the external auditory canal and so ensure measurement accuracy. The presence of impacted cerumen will likely result in inaccurate measurements. The only potential harm as a result of measuring vital signs was associated with glass mercury thermometers, in terms of rectal perforation, the risk of mercury poisoning was not clearly established.Conclusions Although there has been considerable research undertaken on many specific aspects of vital sign measurement, there is an urgent need for further primary research into the more general issues such as what parameters should be measured, the optimal frequency of measurements and the role of new technology in patient monitoring.

Vital signs

Background Vital signs traditionally consist of blood pressure, temperature, pulse rate and respiratory rate, and are an important component of monitoring the patient's progress during hospitalisation. An initial search of the literature indicated that there was a vast volume of published information relating to this topic; however, there had been no previous attempt to systematically review this literature. This review was therefore initiated to identify, appraise and summarise the best available evidence relating to the measurement of vital signs in hospital patients. Objectives The objectives of this review were to present the best available information related to the monitoring of patient vital signs with regard to their purpose, limitations, optimal frequency of measurements, and what measures should constitute vital signs. The review also sought to identify additional issues of importance related to the individual parameters of temperature measurement, blood pressure assessment, pulse rate measurement and respiratory rate measurement. Review methods This review considered all studies that related to the objectives and included neonatal, paediatric and/or adult hospital patients. The outcome measures of interest were those related to the accuracy of, required frequency of or the need for vital signs. The review also considered any study addressing some aspect of vital signs measurement to ensure all issues of importance were identified. The search sought to find both published and unpublished studies. Databases searched included CINAHL, Medline, Current Contents, Cochrane Library, Embase and Dissertation Abstracts. The references of all identified studies were examined for additional references. All studies were checked for methodological quality, and data was extracted using a data extraction tool. Results Although a variety of measures may be useful additions to the traditional four vital sign parameters, only pulse oximetry and smoking status have been shown to change patient care and outcomes. There are suggestions that vital sign monitoring has become a routine procedure, but little useful information was identified in regard to the optimal frequency of vital sign measurement. It was noted that many of the important issues related to vital sign measurement have not been investigated through research. There is currently only limited research related to respiratory rate as a vital sign; however, its value as an indicator of serious illness has not been reliably established. There is only limited research relating to pulse rate measurements. Although routinely used for all hospital patients, the ability to detect serious physiological changes by assessment of pulse rate has not been rigorously evaluated. Many factors were identified that could potentially influence the accuracy of blood pressure measurement. Auscultation is accurate for the measurement of systolic blood pressure using phase I Korotkoff sound as the reference point, and for diastolic pressure if phase V Korotkoff sounds are used. Cuff size can influence accuracy, in that using a cuff that is too narrow will likely overestimate blood pressure and a cuff that is too wide will underestimate the pressure. Research suggests that blood pressure should be measured on the upper arm, while the arm is resting at approximate heart level. Studies have shown that healthcare workers often measure blood pressure in an incorrect and inaccurate way, and this is of some concern. However, a small number of studies suggest that education programs can be effective in improving blood pressure measurement techniques. The largest volume of research identified during this review related to the measurement of temperature. For accurate measurement of oral temperatures the thermometer should be positioned in either the left or right posterior sublingual pocket and remain in the mouth for 6–7 min. Although oxygen therapy and different types of breathing patterns will not influence accuracy of oral temperature measurements, hot or cold liquids will. For the measurement of tympanic temperatures, an ear tug should be used to help straighten the external auditory canal and so ensure measurement accuracy. The presence of impacted cerumen will likely result in inaccurate measurements. The only potential harm as a result of measuring vital signs was associated with glass mercury thermometers, in terms of rectal perforation, the risk of mercury poisoning was not clearly established. Conclusions Although there has been considerable research undertaken on many specific aspects of vital sign measurement, there is an urgent need for further primary research into the more general issues such as what parameters should be measured, the optimal frequency of measurements and the role of new technology in patient monitoring.

Vital signs.

Vital signs traditionally consist of blood pressure, temperature, pulse rate and respiratory rate, and are an important component of monitoring the patient's progress during hospitalisation. An initial search of the literature indicated that there was a vast volume of published information relating to this topic; however, there had been no previous attempt to systematically review this literature. This review was therefore initiated to identify, appraise and summarise the best available evidence relating to the measurement of vital signs in hospital patients. The objectives of this review were to present the best available information related to the monitoring of patient vital signs with regard to their purpose, limitations, optimal frequency of measurements, and what measures should constitute vital signs. The review also sought to identify additional issues of importance related to the individual parameters of temperature measurement, blood pressure assessment, pulse rate measurement and respiratory rate measurement. This review considered all studies that related to the objectives and included neonatal, paediatric and/or adult hospital patients. The outcome measures of interest were those related to the accuracy of, required frequency of or the need for vital signs. The review also considered any study addressing some aspect of vital signs measurement to ensure all issues of importance were identified. The search sought to find both published and unpublished studies. Databases searched included CINAHL, Medline, Current Contents, Cochrane Library, Embase and Dissertation Abstracts. The references of all identified studies were examined for additional references. All studies were checked for methodological quality, and data was extracted using a data extraction tool. Although a variety of measures may be useful additions to the traditional four vital sign parameters, only pulse oximetry and smoking status have been shown to change patient care and outcomes. There are suggestions that vital sign monitoring has become a routine procedure, but little useful information was identified in regard to the optimal frequency of vital sign measurement. It was noted that many of the important issues related to vital sign measurement have not been investigated through research.There is currently only limited research related to respiratory rate as a vital sign; however, its value as an indicator of serious illness has not been reliably established. There is only limited research relating to pulse rate measurements. Although routinely used for all hospital patients, the ability to detect serious physiological changes by assessment of pulse rate has not been rigorously evaluated. Many factors were identified that could potentially influence the accuracy of blood pressure measurement. Auscultation is accurate for the measurement of systolic blood pressure using phase I Korotkoff sound as the reference point, and for diastolic pressure if phase V Korotkoff sounds are used. Cuff size can influence accuracy, in that using a cuff that is too narrow will likely overestimate blood pressure and a cuff that is too wide will underestimate the pressure. Research suggests that blood pressure should be measured on the upper arm, while the arm is resting at approximate heart level. Studies have shown that healthcare workers often measure blood pressure in an incorrect and inaccurate way, and this is of some concern. However, a small number of studies suggest that education programs can be effective in improving blood pressure measurement techniques. The largest volume of research identified during this review related to the measurement of temperature. For accurate measurement of oral temperatures the thermometer should be positioned in either the left or right posterior sublingual pocket and remain in the mouth for 6-7 min. Although oxygen therapy and different types of breathing patterns will not influence accuracy of oral temperature measurements, hot or cold liquids will. For the measurement of tympanic temperatures, an ear tug should be used to help straighten the external auditory canal and so ensure measurement accuracy. The presence of impacted cerumen will likely result in inaccurate measurements. The only potential harm as a result of measuring vital signs was associated with glass mercury thermometers, in terms of rectal perforation, the risk of mercury poisoning was not clearly established. Although there has been considerable research undertaken on many specific aspects of vital sign measurement, there is an urgent need for further primary research into the more general issues such as what parameters should be measured, the optimal frequency of measurements and the role of new technology in patient monitoring.

Influence of breathing pattern on the esophagogastric junction pressure and esophageal transit.

The esophagogastric junction (EGJ) is guarded by two sphincters, a smooth muscle lower esophageal sphincter (LES) and a skeletal muscle crural diaphragm. The LES relaxes in response to a swallow but the crural diaphragm does not. Since contraction of the crural diaphragm is affected by the pattern of breathing, the latter may also influence the EGJ pressure and swallow-induced EGJ relaxation. Our aims were to study the effects of alterations of the breathing pattern on the EGJ pressure, swallow-induced EGJ relaxation, and esophageal transport of liquid bolus. Manometric, electromyographic, and videofluoroscopic studies were performed in 12 healthy subjects. The subjects were trained in two types of breathing patterns, hyperventilation and partial expiration, using the visual biofeedback from their own respiratory waveform. Hyperventilation increased the frequency of inspiratory pressure oscillations at the EGJ without affecting the end-expiratory EGJ pressure. Partial expiration resulted in an increase in the end-expiratory EGJ pressure. Swallow-induced relaxation at the EGJ was markedly reduced during partial expiration. An inspiration during a swallow (control breathing and hyperventilation) caused transient interruption of flow across the EGJ. Partial expiration resulted in cessation of the flow across the EGJ, failure of esophageal peristalsis to traverse the entire length of the esophagus, increased esophageal transit time, and incomplete esophageal clearance of a liquid bolus.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in breathing patterns after lung operations.

To assess the effects of thoracic surgery on breathing patterns without conscious intervention, we analyzed and compared the breathing patterns observed immediately before and after surgical procedure while anesthesia was maintained with enflurane and nitrous oxide at a constant level in 15 patients undergoing thoracic surgery. Our results showed that immediately after the surgical procedure, respiratory frequency (f) was significantly higher and tidal volume (V(T)) was significantly smaller than those observed immediately before the surgical procedure. The increased f during the period immediately after the surgical procedure was due to shortening of both inspiratory time (T(I)) and expiratory time (T(E)) without changing the ratio of T(I) to the total breath time (T(tot)). Despite the significant decrease in V(T) observed immediately after the surgical procedure, the value of negative pressure during the occluded inspiration (P(max)) was significantly higher than that observed immediately before the surgical procedure. These results indicate that a rapid, shallow type of breathing pattern can occur after thoracic surgery without conscious intervention.

Altered breathing pattern elicited by stimulation of abdominal visceral afferents.

The effect of stimulation of afferent mesenteric nerves on tidal volume (VT), phrenic nerve, and external intercostal muscle activities was studied in anesthetized spontaneously breathing cats. Both mechanical distension of the small intestine and electrical stimulation of the mesenteric nerves resulted in an initial inspiratory inhibition of VT followed by a gradual recovery above the prestimulus controls. Changes in VT were accompanied by a depression of phrenic nerve activity and an excitation of external intercostal muscle activity. During the recovery phase of VT, the amplitude of phrenic nerve activity returned only partially, whereas the activity of the external intercostal muscle was greater than the prestimulus controls. In a second group of experiments, brief tetanic stimulation at the beginning of inspiration led to a complete and maintained inhibition of phrenic nerve activity but with a simultaneous excitation of external intercostal muscle activity and without any change in VT; whereas expiratory stimulation caused a decrease in expiratory abdominal muscle activity, without changing the peak amplitude of phrenic nerve activity. The respiratory changes observed with distension of the small intestine were abolished after denervation of the mesenteric plexus. It is concluded that activation of the visceral afferents of the mesenteric region reflexly changes diaphragmatic breathing to intercostal breathing. It is assumed that such a type of breathing pattern may occur in pregnancy and in pathophysiological situations involving splanchnic viscera.

Chest wall movements during inspiratory loading in dogs.

In 12 anesthetized mongrel dogs the changes in movements of the rib cage (RC) and abdomen (ABD) were studied during inspiratory loading for 15 min. Tracheal (Pm) and transdiaphragmatic (Pdi) pressures increased to 60-65% of their maxima and were maintained for the 15-min period of loading. Analysis of the EMGs of the diaphragm and intercostals revealed approximately equal recruitment of both these muscle groups. Two types of breathing patterns were observed: (1) abdominal, or normal (9/12 dogs), in which the ABD moved outward during inspiration, and (2) rib cage (3/12 dogs) in which the RC moved outward and the ABD inward during inspiration. The latter were those in whom the ratio of RC width to length was the greatest, and the RC was, presumably, able to resist deformation during inspiration. In most of the abdominal (normal) breathers two phases of RC motion could be seen an initial phase which was either outward or inward, and a final, early expiratory, phase of outward motion. The data indicate that the initial phase of RC motion is influenced by the relative compliance of the RC and ABD, while the final phase relates to the respiratory system rebounding to its relaxation configuration at the onset of respiration.