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PubMed1991

Transcranial Doppler monitoring during carotid endarterectomy.

Transcranial Doppler monitoring of the middle cerebral artery blood flow velocity was used as an adjunct to routine methods of cerebral monitoring in a prospective study of 30 consecutive patients undergoing carotid endarterectomy to investigate whether transcranial Doppler monitoring provided information influencing operative technique. Application of carotid clamps caused a significant fall in middle cerebral artery velocity and there was a linear relationship between middle cerebral artery velocity and internal carotid artery stump pressure. Assuming a stump pressure of less than 50 mmHg to be an indication for shunting, this would correspond to a systolic middle cerebral artery velocity of less than 42 cm/s and a mean velocity of less than 30 cm/s. Transcranial Doppler monitoring immediately identified problems with shunt function and demonstrated a higher frequency of intraoperative embolization than had been anticipated, particularly after shunt insertion and final restoration of flow. With revision of operative technique this phenomenon is rarely encountered now. Two of the 30 patients exhibited a minor neurological deficit on recovery of consciousness, and transcranial Doppler monitoring was able to identify the probable underlying cause in both cases. Unnecessary and potentially hazardous re-exploration was avoided. In the absence of transcranial Doppler monitoring the neurological deficit in one of the patients might have been much worse.

Blood Flow Velocity↗
PubMed1991

The otolaryngologic manifestations of gastroesophageal reflux disease (GERD): a clinical investigation of 225 patients using ambulatory 24-hour pH monitoring and an experimental investigation of the role of acid and pepsin in the development of laryngeal injury.

Occult (silent) gastroesophageal reflux disease (GER, GERD) is believed to be an important etiologic factor in the development of many inflammatory and neoplastic disorders of the upper aerodigestive tract. In order ot test this hypothesis, a human study and an animal study were performed. The human study consisted primarily of applying a new diagnostic technique (double-probe pH monitoring) to a population of otolaryngology patients with GERD to determine the incidence of overt and occult GERD. The animal study consisted of experiments to evaluate the potential damaging effects of intermittent GER on the larynx. Two hundred twenty-five consecutive patients with otolaryngologic disorders having suspected GERD evaluated from 1985 through 1988 are reported. Ambulatory 24-hour intraesophageal pH monitoring was performed in 197; of those, 81% underwent double-probe pH monitoring, with the second pH probe being placed in the hypopharynx at the laryngeal inlet. Seventy percent of the patients also underwent barium esophagography with videofluoroscopy. The patient population was divided into seven diagnostic subgroups: carcinoma of the larynx (n = 31), laryngeal and tracheal stenosis (n = 33), reflux laryngitis (n = 61), globus pharyngeus (n = 27), dysphagia (n = 25), chronic cough (n = 30), and a group with miscellaneous disorders (n = 18). The most common symptoms were hoarseness (71%), cough (51%), globus (47%), and throat clearing (42%). Only 43% of the patients had gastrointestinal symptoms (heartburn or acid regurgitation). Thus, by traditional symptomatology, GER was occult or silent in the majority of the study population. Twenty-eight patients (12%) refused or could not tolerate pH monitoring. Of the patients undergoing diagnostic pH monitoring, 62% had abnormal esophageal pH studies, and 30% demonstrated reflux into the pharynx. The results of diagnostic pH monitoring for each of the subgroups were as follows (percentage with abnormal studies): carcinoma (71%), stenosis (78%), reflux laryngitis (60%), globus (58%), dysphagia (45%), chronic cough (52%), and miscellaneous (13%). The highest yield of abnormal pharyngeal reflux was in the carcinoma group and the stenosis group (58% and 56%, respectively). By comparison, the diagnostic barium esophagogram with videofluoroscopy was frequently negative. The results were as follows: esophagitis (18%), reflux (9%), esophageal dysmotility (12%), and stricture (3%). All of the study patients were treated with antireflux therapy. Follow-up was available on 68% of the patients and the mean follow-up period was 11.6 +/- 12.7 months.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1995

Direct spinal stimulation for intraoperative monitoring during scoliosis surgery.

Intraoperative electrophysiological monitoring of the spinal cord has traditionally been done by recording somatosensory evoked potentials (SEP). There is a risk that SEPs can be unaltered when significant injury to the anterior spinal cord has occurred. The purpose of this report is to describe a simple technique for intraoperative spinal cord stimulation which monitors descending pathways in the anterior spinal cord. Stimulation occurs through needle electrodes inserted into spinous processes in the rostral surgical wound, and recordings are made from electrodes in the popliteal spaces. We report our experience in monitoring spinal instrumentation in 45 patients with idiopathic scoliosis and 20 with some form of neurological disease causing scoliosis. The neurogenic motor evoked potentials (NMEP) are stable and easily recorded from the popliteal spaces in the majority of patients. We describe the case of 1 patient with Friedreich's ataxia in whom no SEPs could be recorded, but NMEPs were used successfully for monitoring. We have fond that combining traditional SEP monitoring with NMEP recording provides a safe and effective method to monitor the spinal cord during surgical procedures where it is at risk.

Adolescent↗
PubMed1990

Comparison of transthoracic impedance/heart rate monitoring and pulse oximetry for patients using diaphragm pacemakers.

Patients using diaphragm pacemakers have several respiratory-related problems placing them at high risk for death during sleep, including central hypoventilation, abnormal arousal responses, upper airway and/or tracheostomy obstruction, and, in the case of high quadriplegia, lack of motor response to airway obstruction. The recent death from airway obstruction of a patient using diaphragm pacemakers prompted us to re-evaluate both the need for home monitoring and the type of monitor to prescribe. We compared the performance of a transthoracic impedance/heart rate (TI/HR) monitor with that of a pulse oximeter in six patients with central hypoventilation syndrome whose treatment included diaphragm pacing. Polygraphic recordings of airflow, ECG, SaO2, transthoracic impedance, heart rate, and breath detection were obtained during brief tracheostomy occlusion during patient sleep. Although none of 13 occlusions was detected by the TI/HR monitor, the pulse oximeter identified 13 of 13 occlusions. Three reasons for TI/HR monitor failure included 1) the breath detection circuit consistently registered a breath with each obstructed, paced diaphragmatic contraction; 2) bradycardia did not occur during any airway occlusion; and 3) pacemaker stimuli were misinterpreted as additional heart beats, increasing apparent heart rate. Thus, pulse oximetry, but not TI/HR monitoring, can detect life-threatening airway obstruction in children using diaphragm pacemakers.

Adolescent↗
PubMed2005

Brain tissue oxygen (PtiO2): a clinical comparison of two monitoring devices.

BACKGROUND: We investigated the difference between two commercially available sensors for continuous monitoring of brain tissue oxygen (PtiO2). One is a single parameter probe for PtiO2 monitoring (Licox), the other is a multiparamter sensor (Neurotrend) further including measurement of brain temperature, pH, and partial pressure of tissue carbon dioxide. METHODS: In seven patients after subarachnoid hemorrhage or traumatic brain injury continuous monitoring of PtiO2 was performed simultaneously using Licox and Neurotrend. FINDINGS: Mean PtiO2 was generally lower when assessed by the Neurotrend, as compared with the Licox (Licox 27.7 mmHg vs. Neurotrend 20.9 mmHg; P = 0.028). The amplitude of PtiO2 elevations during ventilation with 100% oxygen was higher with the Licox, but this did not reach statistical significance (Licox 55.2 mmHg vs. Neurotrend 50.2 mmHg, P = 0.082). Regarding clinical stability of the sensors, only one Neurotrend sensor provided valid function over the desired monitoring period. Five Neurotrend sensors dislocated or broke and one sensor did not show any function after insertion. No malfunction occurred with the Licox sensors. CONCLUSIONS: Our results suggest that PtiO2 might be lower when assessed by the Neurotrend sensor. The clinical stability of the Neurotrend sensor was of concern and allowed monitoring in one of seven patients over the desired monitoring period of several days only.

Brain Injuries↗
PubMed1999

Aquatic biotoxins: design and implementation of seafood safety monitoring programs.

Naturally occurring toxicants are usually odorless, tasteless, and generally undetectable by any simple chemical test. Various programs have been established that are effective in reducing risks associated with these toxicants in food. These programs include setting regulatory limits, monitoring susceptible commodities for toxin levels, and using decontamination procedures. Bioassays have been used traditionally to monitor suspect products. All traditional bioassays, however, have one common disadvantage, i.e., the lack of specificity for individual toxins. The lack of available reference standards for specific toxins has also hampered implementation of monitoring programs. Utilizing the knowledge gained with regulatory monitoring and decontamination programs for other toxins, e.g., aflatoxin, similar seafood safety programs can be developed for aquatic biotoxins that will reduce risks and hazards associated with the contaminant to practicable levels and help to preserve an adequate food supply. Research is needed in several areas identified in this article. International cooperation has an important role in achieving these essential elements. Global programs will help in the adequate management of risks associated with aquatic biotoxins. To have an effective monitoring program, it is necessary to define precisely the local needs for information in a short or long time range. It is necessary to have basic knowledge about the biological, chemical, and physical conditions as well as temporal and geographic variations within the region of interest (2). Regardless of the overall success of fish/shellfish toxin monitoring plans, emergencies will occur. Therefore, contingency plans should be developed so there will be no misunderstanding of what actions to take (148). In general, however, the structure of the program must be kept as simple as possible to facilitate fast and uncomplicated flow of information among the various organizations and individuals involved (2). Public health and safety requires the removal of any toxic shellfish from the market, within practicability, and closure of any suspect harvest area. It should be important to remember that economic value of the fish or shellfish resource is always secondary to public health and safety (148).

Environmental Monitoring↗
PubMed2004

Motor evoked potential monitoring for spinal cord and brain stem surgery.

Intraoperative Neurophysiology (ION) has established itself as one of the means by which modern neurosurgery can improve surgical results while minimizing morbidity. The advent of motor evoked potential (MEP) monitoring represents a landmark in this recent progress. ION consists of monitoring (the continuous "on-line" assessment of the functional integrity of neural pathways) and mapping (the functional identification and preservation of anatomically ambiguous nervous tissue) techniques. In this chapter we have attempted to critically review the evolution of MEP use during monitoring and mapping techniques for neurosurgical procedures in the brainstem and the spinal cord, providing the neurophysiological theoretical background and practical aspects of clinical applications. According to the experience from our and other groups involved in ION, we suggest the following: 1) ION is mandatory whenever neurological complications are expected as predicted by a known pathophysiological mechanism. It is therefore advisable to perform ION when dealing with brain stem and intramedullary spinal cord lesions. 2) MEP monitoring after transcranial electrical stimulation is today a feasible and reliable technique for use under general anesthesia. MEP monitoring is the most appropriate technique to assess the functional integrity of descending motor pathways in the brainstem and, foremost, in the spinal cord. 3) Mapping of the corticospinal tract at the level of the cerebral peduncle as well as mapping of the VII, IX-X and XII cranial nerve motor nuclei on the floor of the fourth ventricle is of great value with which to identify "safe entry zones" into the brainstem. 4) Other techniques, although safe and feasible, still lack rigorous validation in terms of prognostic value and correlation with the postoperative neurological outcome. These techniques include mapping of the corticospinal tract within the spinal cord and monitoring of the corticobulbar tracts. These techniques, however, are expected to open new perspectives in the near future.

Adult↗
PubMed2004

Motor evoked potential monitoring for the surgery of brain tumours and vascular malformations.

Brain surgery incurs a significant risk of a new motor deficit in lesions within or adjacent to the motor areas and pathways which, for the patient, presents one of the most disabling complications of such operations. It is a major concern of intracranial procedures to delineate and monitor motor regions in order to preserve their structural and functional integrity, while still achieving maximal cytoreduction. The technique of motor evoked potential recording has had to be adapted to intraoperative recording conditions under general anaesthesia, but has been available for clinical use now for almost ten years. This contribution summarizes the current technique and related methods, as well as our clinical experience in some 400 cases of MEP monitoring in supratentorial tumors, lesions in and around the brainstem, and aneurysm surgery. Intraoperative MEP recordings have been shown to reliably reflect an impending new motor deficit. Irreversible MEP deterioration heralds new paresis, and unaltered recordings predict preserved motor function. This is also true in aneurysm surgery where conventional SEP monitoring may yield false-negative results with regard to development of a new motor deficit. Moreover, if MEP deterioration can be reversed, or halted by early surgical intervention, the presence of only a transient motor deficit, or even the lack of a new postoperative deficit, indicates the success of the MEP monitoring method in the prevention of a significant motor impairment. Certain complicated lesions can only be operated on at all because MEP monitoring is available. In conclusion, intraoperative MEP monitoring is a useful aid in brain surgery with which to avoid a new motor deficit without compromise to the surgical result. Controlled prospective studies will be required to verify the clinical value of the method.

Brain Mapping↗
PubMed1986

Polysomnographic studies and home monitoring of siblings of SIDS victims and of infants with no family history of sudden infant death.

We report preliminary results of a prospective study conducted to prevent sudden death in asymptomatic infants. From 1977-1984, 3658 infants were studied polygraphically. There were 923 siblings of SIDS victims and 2735 infants with no personal of family history of SIDS. The infants were studied at 8 weeks of age. Polygraphic "risk factors" were defined by central apnoeas longer than 15 s; periodic breathing above 5% sleep time; or obstructive apnoeas above 3 s. In 937 infants "risk factors" were seen and a second study was requested 4 weeks later. Out of 891 infants re-studied at 12 weeks, 153 still presented some "risk factors" and were selected for a home monitoring programme; 150 families agreed to monitor their infants at home with a cardiorespiratory monitor with the alarms set at 20 s apnoea, and 50 beats per min bradycardia. Repeated alarms were reported for 97/150 (65%) infants; 48/150 (32%) infants were stimulated and 8/150 (5.3%) were resuscitated on at least one occasion. No death occurred during monitoring, which could be interrupted before the end of the first year of life in all infants. In the group of 3459 infants with normal results and not monitored, three siblings (0.35%) and one infant without history (0.04%) died of SIDS. Of the infants with abnormal polygraphic results, one sibling not returned for the second recording, and two out of three infants for whom the parents refused monitoring, died of SIDS. It is concluded that the programme, may prevent the death of some infants, but that the outcome of a child with normal results cannot be foreseen.

Arrhythmias, Cardiac↗
PubMed1982

Home monitoring of infants considered at risk for the sudden infant death syndrome. Four years' experience (1977-1981).

From 1977 to 1981, 500 infants had been referred to evaluate their risk for the sudden infant death syndrome (SIDS). These included 186 infants who had presented an event (prolonged apnea, hypotonia, pallor or cyanosis) initiated while asleep, 133 siblings and 181 "controls". All-night polygraphic recordings were performed in all infants, and if indicated by the history of the infants, complementary clinical investigations were done. These procedures led to the identification of 50 infants considered at risk for SIDS (10% of all referrals): 30 near-misses for SIDS, 10 siblings and 10 infants with a minor incident during sleep but with abnormal polygraphic recordings. These 50 infants (group I) were monitored at home during sleep with the help of a cardiac and respiratory monitor. Eight infants not considered at risk were monitored similarly at the request of their parents (group II). Forty of the 50 infants in group I presented with repetitive sleep apneas and bradycardias, and required stimulation by their parents to regain normal cardiorespiratory rhythm. Twelve had to be resuscitated at least once for a life-threatening event. None of the infants in group II showed alarms during sleep. Monitoring could be discontinued after a mean length of 7.2 months for the infants in group I, 4.1 months in group II. It is concluded that if identified in time through adequate investigations, some infants may be protected against SIDS through home monitoring. This approach requires expensive and well trained teams, ready, at any time, to cope with the problems that may arise in the homes of the monitored infants.

Ambulatory Care↗
PubMed1987

Continuous monitoring of alveolar and inspiratory concentrations of anesthetic and respiratory gases is difficult and potentially unsafe.

One essayist suggests that continuous monitoring of alveolar and inspiratory concentrations of anesthetic and respiratory gases has little or no positive effect on patient outcome and may even be detrimental to patients. Such monitoring, he says, tends to remove anesthesiologists from personal contact with their patients. He recommends careful monitoring of fresh gas concentrations leaving the anesthetic machine, careful monitoring of inspired gas in a circle absorption breathing system, and improved training of anesthesiologists to prevent human error. Another essayist suggests that continuous monitoring of alveolar and inspiratory concentrations of anesthetic and respiratory gases is cost-effective and relatively simple. He says that such monitoring, without being a source of legal problems for its users, improves the quality of patient care.

Anesthesiology↗
PubMed1989

Neurophysiologic monitoring in posterior fossa surgery. I. Technical principles, applicability and limitations.

In 135 cases of posterior fossa surgery almost exclusively in the cerebellopontine angle (CPA) intraoperative monitoring of brain-stem acoustic evoked potentials (BAEP) and partly somatosensory evoked potentials (SEP) was performed. The series consisted of 20 microvascular decompressions, 63 acoustic neurinomas, 7 vascular lesions and 45 other space occupying lesions, mostly in the CPA. BAEP monitoring alone was employed in 76 cases, combined BAEP and SEP monitoring less frequently. The technique of anaesthesia and intraoperative monitoring is presented in detail including an analysis of technical problems (17 in 135 = 13% of cases) and technical failures (11 of 135 = 8%). The results of monitoring brainstem pathways contralateral to the lesion are detailed. It is concluded that the technical principles of evoked potential monitoring in posterior fossa surgery are well established. The applications and limits of this technique including its modifications are described.

Cranial Fossa, Posterior↗
PubMed1989

Vestibulospinal evoked potential versus motor evoked potential monitoring in experimental spinal cord injuries of cats.

Changes in vestibulospinal evoked potentials (VsEP) and motor evoked potentials (MEP) were examined in 10 cats before and after two different weight-dropping spinal cord injuries. In six animals somatosensory evoked potentials (SEP) were also monitored. The recordings were done from epidural spinal cord electrodes. Before and after severe and light weight-dropping spinal cord injuries all 3 modalities were recorded at the same time intervals till the end of 4th hour postinjury. According to a scoring system, evoked potential changes below and above the level of injury were monitored, and compared with each other. This study showed that the different motor stimulation methods use different descending spinal tracts, and both can be useful as a monitoring tool. Both descending tracts carrying VsEP and MEP had similarly remarkable changes after severe spinal cord injury. These consisted of major deformation, development of an evoked injury potential and complete potential loss. During the 4 hour monitoring period, no case showed EP recovery in the severe injury group. Light spinal cord injury caused somewhat more deterioration in MEPs than VsEP. The higher numbers of severe potential alterations in the lightly injured animals suggest that MEP is a more sensitive method for spinal cord monitoring compared to VsEP and also to SEP. On the other hand, this sensitivity might be a disadvantage during intraoperative monitoring, if MEP alone were used.

Action Potentials↗
PubMed1989

Reliability of 24-hour home esophageal pH monitoring in diagnosis of gastroesophageal reflux.

Twenty-four-hour home esophageal pH monitoring is proposed in order to study gastroesophageal reflux (GER) so that prolonged use of costly hospital equipment and staff can be curtailed and the diagnostic accuracy of the examination improved. Eighty-six patients affected by GER symptoms and 20 healthy volunteers underwent 24-hr home esophageal pH monitoring, x-rays, and endoscopy of the upper gastrointestinal tract to investigate reliability of outpatient recording. Fifteen more patients consecutively underwent out- and inpatient recording to detect possible differences between these methods in the two daily periods. Outpatient monitoring was well tolerated in 94.7% of the patients; 14.3% of them markedly reduced their routine activities. The range of normality of outpatient recording does not differ from that of inpatients. In the 15 patients who consecutively underwent out- and inpatient monitoring, no significant differences were reported. The sensitivity of 24-hr home esophageal pH recording is 0.85, the specificity 1, the accuracy for negative prediction 0.68, and the accuracy for positive prediction 1. The reliability of 24-hr home esophageal pH monitoring is comparable to inpatient recording. It allows hospital cost reduction and is also better tolerated by patients but has not greatly improved the diagnostic accuracy of the gastroesophageal reflux pH monitoring.

Adult↗
PubMed1992

Correlated, simultaneous, multiple-wavelength optical monitoring in vivo of localized cerebrocortical NADH and brain microvessel hemoglobin oxygen saturation.

Current forms of brain monitoring, such as electroencephalography (EEG), have had limited clinical utility. The EEG records spontaneous cerebrocortical activity and thus is an indirect indicator of metabolic demand and, to a lesser extent, an indicator of mismatch of supply versus demand. Ischemia modulates EEG activity in ways that can usually be detected, but EEG patterns can be similarly modulated by many other factors, including temperature and pharmacologic manipulation. This in vivo study in physiologically monitored animals evaluated the use of correlated optical spectroscopy, performed with an instrument having a fiberoptic light-guide bundle in contact with the cerebral cortex, for the simultaneous monitoring of cerebrovascular oxygen availability and intracellular oxygen delivery. A highly specific monitor of cerebral intracellular oxygen supply, the cerebrocortical intramitochondrial NADH redox state, was monitored in vivo with a fluorescence technique. Absorption spectroscopy was used concurrently to monitor hemoglobin content (blood volume) and oxygen saturation in the microcirculation. Correlated changes in optical signals from cerebrocortical NADH and hemoglobin were studied in a swine model (n = 7) of nitrogen hypoxia. Measurements were made at four wavelengths with a time-division, multiplexed fluorometer/reflectometer. Because the NADH fluorescence signal at 450 nm is affected by local changes in blood volume, a "corrected" fluorescence signal is usually calculated. In previous studies, where only two wave lengths have been measured, attempts at correction were based on reflectance at the excitation wavelength (366 nm). We compared estimators of changes in microcirculatory blood volume using reflection at two wavelengths: 366 nm and 585 nm, the wavelengths for maximum and isobestic absorption. The results of the studies were as follows: (1) during transient hypoxia, NADH and local hemoglobin saturation signals changed in concert with arterial pulse oximetry, with changes in NADH lagging behind changes in saturation by an average of 5.3 seconds; (2) after hypocapnic ventilation to a mean PaCO2 of 20.2 +/- 0.8 mm Hg, NADH increased by 11.5 +/- 8.7% (as compared with maximal change during anoxia), local hemoglobin saturation decreased by 7.7 +/- 6.4%, and local blood volume decreased by 12.5 +/- 13%, while arterial SpO2 was unchanged; (3) our two measures of local blood volume were closely correlated during carbon dioxide perturbations, but poorly correlated during hypoxic perturbation; and (4) NADH fluorescence provided a more rapid, sensitive indicator of oxygen deprivation than did the EEG. During transient hypoxia, EEG changes occurred 57.4 +/- 10.4 seconds after the onset of decline in local hemoglobin saturation, after NADH had completed 50% of its maximal increase.

Animals↗
PubMed1996

Bedside burr hole for intracranial pressure monitoring performed by intensive care physicians. A 5-year experience.

OBJECTIVE: To assess the results of a 5-year experience with bedside burr hole for intracranial pressure (ICP) monitoring performed by intensive care physicians. DESIGN: Prospective, observational study in 120 patients. SETTING: A general-neurologic Intensive Care Unit in a University Hospital. PATIENTS: Patients admitted for acute neural lesion requiring ICP monitoring. METHOD: A 2.71 mm burr hole was made with positioning of a subarachnoid screw, through which a miniaturized fiberoptic, tip transducer device (Camino) was advanced and inserted 2 mm in the frontal cortex. MAIN RESULTS: Over a 5-year period 120 patients, mainly with severe head trauma, underwent ICP monitoring. None of the planned patients was excluded because of technical difficulties. No life-threatening complications were reported, and the overall morbidity rate related to the ICP monitor was 3.3%. Complications were infectious in nature, with 2.5% wound infections and 0.8% meningitis. Although seven patients bled when opening the dura, no intracranial hematomas were recorded due to the ICP monitor. The fiberoptic device was left in place for 5 +/- 1.6 (SD) days (range 1-12 days). Five patients (4.1%) required catheter substitution due to breakage of the system components (fiberoptics). CONCLUSIONS: Bedside insertion of a ICP monitor performed by intensive care physicians is a safe procedure, with a complication rate comparable to other series published by neurosurgeons. The overall morbidity rate is comparable to, or even lower than, that caused by central vein catheterization.

Adolescent↗
PubMed1990

A parallel software architecture for building intelligent medical monitors.

Intensive care units become more complicated each day as the number of devices developed to monitor various aspects of a patient's status continues to increase. Intelligent monitors attempt to reduce this complexity by interpreting the data and presenting a high level summary to the clinician. We propose an innovative parallel software architecture for constructing intelligent medical monitors: the process trellis. The process trellis is an explicitly parallel structure, and therefore can take advantage of the performance gains available from parallel computing hardware. It does not, however, presuppose any expertise in parallel programming on the part of the application programmer. A prototype cardiovascular monitor has been built using this parallel software architecture. Preliminary testing of the monitor has shown that real-time cardiovascular monitoring, including data calculations, symbolic classification, and interpretation can be accomplished in real-time.

Expert Systems↗
PubMed1995

Monitoring respiratory activity in neonates using diaphragmatic electromyograph.

The monitoring of the development of respiratory function in low-birth-weight or sick neonates is important in its overall treatment. The most direct approach to obtaining information on respiratory function is to monitor the activity of the diaphragmatic muscular system rather than measure the resultant change in lung volume or ventilator output, which cannot be guaranteed to be directly related to the neonate's own respiratory activity. The system was designed to assess the feasibility of monitoring respiratory activity in such neonates by measuring the diaphragmatic electromyograph. It is hoped that this system can be used to monitor the development of lung function and possibly, if reliability proves adequate, the synchronisation and control of ventilator assistance. To monitor the EMG, the dominant effect of the ECG was removed using a digital processor. Initial clinical measurements indicate that neonatal respiratory activity can be monitored by measuring the diaphragmatic EMG. Comparative measurements show the EMG method is faster in detecting the inspiratory phase of a breath. Measurements on ventilated neonates showed the presence of intermittent respiratory activity. It also is proposed that clinically relevant information may be deduced from the analysis of the morphology of the detected EMG waveform.

Diaphragm↗