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At least 397 records · Page 22Linked to original sources
PubMed1999

Multicentric study of monitoring alarms in the adult intensive care unit (ICU): a descriptive analysis.

OBJECTIVES: To assess the relevance of current monitoring alarms as a warning system in the adult ICU. DESIGN: Prospective, observational study. SETTINGS: Two university hospital, and three general hospital, ICUs. PATIENTS: Hundred thirty-one patients, ventilated at admission, from different shifts (morning, evening, night) combined with different stages of stay, early (0-3 days), intermediate (4-6 days) and late (> 6 days). INTERVENTIONS: Experienced nurses were asked to record the patient's characteristics and, for each alarm event, the reason, type and consequence. MEASUREMENTS AND MAIN RESULTS: The mean age of the patients included was 59.8 +/- 16.4 and SAPS1 was 15.9 +/- 7.4. We recorded 1971 h of care. The shift distribution was 78 mornings, 85 evenings and 83 nights; the stage distribution was 88 early, 78 intermediate and 80 late. There were 3188 alarms, an average of one alarm every 37 min: 23.7% were due to staff manipulation, 17.5% to technical problems and 58.8% to the patients. Alarms originated from ventilators (37.8%), cardiovascular monitors (32.7%), pulse oximeters (14.9%) and capnography (13.5%). Of the alarms, 25.8% had a consequence such as sensor repositioning, suction, modification of the therapy (drug or ventilation). Only 5.9% of the alarms led to a physician's being called. The positive predictive value of an alarm was 27% and its negative predictive value was 99%. The sensitivity was 97% and the specificity 58%. CONCLUSIONS: The study confirms that the level of monitoring in ICUs generates a great number of false-positive alarms.

Adult↗
PubMed2005

Correlation of arterial PCO2 and PETCO2 in prehospital controlled ventilation.

INTRODUCTION: This study was carried out to estimate the relationship between arterial PCO2 (PaCO2) and end-tidal carbon dioxide (PETCO2) during prehospital controlled ventilation and also to evaluate variation of the gradient between PCO2 and PETCO2 during prehospital transport. METHODS: Measurements of PETCO2 from capnography values and PaCO2 from arterial blood gases were registered at the beginning (T(0)) and at the end (T(end)) of out-of-hospital management. For all patients requiring invasive ventilation, the gradient between PCO2 and PETCO2 was calculated for T(0) and T(end), the PaCO2-PETCO2 variation between T(end) and T(0) was also calculated. RESULTS: One hundred patients were included in this study (mean age, 58.4 +/- 16.4 years; 57 were male). There was no variation of the mean gradient (DeltaPaCO2-PETCO2 ) during transport (8.64 +/- 13.5 mm Hg at T(0) and 7.26 +/- 12.94 mm Hg at T(end)). Thirty-six percent of patients (n = 36) had a gradient above +10 mm Hg, and for 6% of patients (n = 4) the gradient was lower than -10 mm Hg. The PaCO2-PETCO2 gradient was not significantly different according to the pathology, but was significantly higher in hypercapnic patients compared with hypocapnic or normocapnic patients. In patients with severe head injury, the capnia was normalized in 80% of patients at the end of the transport according to the last blood gas result. In this subgroup the DeltaPaCO2-PETCO2 (T(end) - T(0)) gradient was stable between T(0) and T(end) except in 20% of the patients for whom the DeltaPaCO2-PETCO2 was lower than -10 mm Hg. Fifty-four percent of critical care physicians had modified the respiratory setting after the first arterial blood gas results. CONCLUSIONS: The PaCO2 cannot be estimated by the PETCO2 in the prehospital setting. There is wide variation in the gradient between PCO2 and PETCO2 depending on patient condition, and over time, the relationship does not remain constant and thus cannot be useful in prehospital ventilation management.

Adult↗
PubMed2006

Utility of a novel quantitative handheld microstream capnometer during transport of critically ill children.

OBJECTIVE: Critically ill children often require endotracheal intubation before and during interhospital transport. Accurate placement and maintenance of the endotracheal tube (ETT) is crucial. The new Pediatric Advanced Life Support guidelines require confirmation of proper ETT position immediately after intubation and during transport by capnography or end-tidal carbon dioxide (ETco(2)) detection in all children with a perfusing rhythm. Currently, there are no practical alternatives for monitoring ETco(2) during pediatric transport. Therefore, we evaluated NPB-75, a quantitative handheld microstream capnometer, during transport of children to our urban children's hospital. METHODS: Consecutive intubated patients who were transported by ground ambulance or rotorcraft were prospectively enrolled into the study. Physical examination, colorimetric CO(2) detector, pulse oximetry, and, in most cases, chest radiograph confirmed the initial ETT position. The capnometer was then attached, and ETco(2) readings were obtained before and during transport by nurses or respiratory therapists who also completed a brief questionnaire regarding the monitor immediately after every transport. A numerical light-emitting diode display and graphic liquid crystal display waveform confirmed the presence of ETco(2). An audiovisual alarm alerted the transport personnel when CO(2) was not detected. RESULTS: Fifty patients comprised the study group, ages birth to 15.3 years (median, 4 months) and weighing 1.63 to 70 kg (median, 5.25 kg). Nineteen patients were transported by ground ambulance and 31 by rotorcraft. The capnometer confirmed ETT position during transport in all patients. The audiovisual alarm of the capnometer immediately detected a ventilator disconnection from the ETT during one air transport. The size of the device was evaluated as "just right" in 37 of 50 transports, "easy to secure" in 46 of 50, and "useful" in all 50 transports. There were no false-negative readings, occlusion, or kinking of tubing during transport. NPB-75 was specifically useful for setting optimal ventilatory support in 2 patients with raised intracranial pressure who required controlled ventilation. Furthermore, it confirmed adequate ventilation when the ventilator falsely detected a low respiratory rate in a newborn with a congenital heart disease for whom pulse oximetry was unreliable. The ETco(2) waveform detected air trapping in 2 ventilated asthmatic patients. CONCLUSIONS: This lightweight microstream capnometer with a 4-hour battery life and audiovisual alarms functioned well in the prehospital setting. It provided both quantitative and graphic real-time detection of ETco(2) in intubated patients, which was of critical importance for the optimal management of patients during transport.

Adolescent↗
PubMed2006

The utility of supplemental oxygen during emergency department procedural sedation and analgesia with midazolam and fentanyl: a randomized, controlled trial.

STUDY OBJECTIVE: To determine whether supplemental oxygen reduces the incidence of hypoxia by 20% in study patients receiving midazolam and fentanyl for emergency department procedural sedation and analgesia. METHODS: Patients were randomized to receive either supplemental oxygen or compressed air by nasal cannula at 2 L per minute. Physicians were blinded to the gas used and end-tidal carbon dioxide (ETCO2) data. Respiratory depression was defined a priori as oxygen saturation less than 90%, ETCO2 level greater than 50 mm Hg, an absolute change from baseline of 10 mm Hg, or loss of the ETCO2 waveform. RESULTS: Of the 80 patients analyzed, 44 received supplemental oxygen and 36 received compressed air. Twenty supplemental oxygen patients and 19 compressed air patients met at least 1 criterion for respiratory depression. Six supplemental oxygen patients and 5 compressed air patients experienced hypoxia (P=.97; effect size 0%; 95% confidence interval -15% to +15%). Fourteen patients in each group met ETCO2 criteria for respiratory depression but were not hypoxic. Physicians identified respiratory depression in 8 of 11 patients who became hypoxic and 0 of 28 patients who met ETCO2 criteria for respiratory depression but who did not become hypoxic. There were no adverse events. CONCLUSION: Supplemental oxygen did not reduce (or trend toward reducing) the incidence of hypoxia in patients moderately sedated with midazolam and fentanyl. However, our lower-than-expected rate of hypoxia limits the power of this comparison. Blinded capnography frequently identified respiratory depression undetected by the treating physicians.

Adolescent↗
PubMed2004

Monitoring carbon dioxide in critical care: the newest vital sign?

Carbon dioxide (CO(2)) monitoring can yield substantial information about cardiac and pulmonary function. Because capnography is not complicated, it is relatively easy to apply in a wide variety of clinical settings. A new area of CO(2) measurement is sublingual CO(2). Although outcomes data are as yet unavailable for this technology, its ease of use makes it an attractive monitoring tool to assess severity of illness and predict patients' responses to therapy. This article describes the pathophysiology and clinical applications of the technologies and describes why they may well be "the newest vital signs."

Adult↗
PubMed1998

Glottic positioning of the endotracheal tube tip: a diagnostic dilemma.

Distal placement of the endotracheal tube tip in the glottic opening is rarely discussed in most emergency medicine, surgery, and prehospital medicine texts. We report three cases of glottic intubation recognized after the patients were thought to have been successfully intubated. Glottic positioning of the endotracheal tube tip went unrecognized initially because of the absence of air heard over the epigastrium, the presence of bilateral breath sounds, and acceptable readings by both pulse oximetry and capnography. Recognition of this complication is aided by the use of radiographic findings, inappropriate endotracheal tube depth, and the presence of inadequate ventilatory volumes. Potential complications of glottic intubation include dislodgement of the endotracheal tube, kinking of the tube, and inadequate protection of the airway.

Adult↗
PubMed1998

Another portable quantitative capnometer.

A new portable quantitative capnometer (Bruker CO2 Module) was tested in an animal lab (mini-pigs) during experiments on air embolism. The end-tidal CO2 values, as measured with this device, showed good agreement with the values of a stationary capnography unit. This device seems suited for quantitative capnometry in the prehospital setting.

Animals↗
PubMed2002

The esophageal detector bulb in the aeromedical setting.

To determine the accuracy of the Esophageal Detector Bulb (EDB) in the aeromedical setting, we conducted a prospective, observational study of all intubated patients transported by an aeromedical program over two years. Flight personnel recorded the results of the EDB, clinical examination, pulse oximetry, and capnography (ETCO(2)). Endotracheal tube position was confirmed by prehospital ETCO(2) or by the receiving emergency physician. There were 104 EDB assessments in 53 patients. The EDB correctly identified four of five esophageal intubations and 96 of 99 tracheal intubations. The sensitivity and specificity of the EDB in the detection of an esophageal intubation were 80% (95% CI, 38-96%) and 97% (95% CI, 92-99%), respectively, and the overall accuracy was 96% (95% CI, 90-98%). The EDB augments the ability of an aeromedical crew to determine endotracheal tube position, but its results must be carefully interpreted in the context of other available means of confirmation of endotracheal tube position.

Adolescent↗
PubMed2003

[Assessment of end-tidal CO2 in the pleural chest tube during lung volume reduction surgery].

Surgery for emphysema is considered as one of the most challenging procedure for anaesthesiologist. Because of the critical illness of such patient, perioperative monitoring is important. Ventilatory monitoring is often difficult or impossible due to a possible massive air leak during the procedure. This case described how ETCO2 was assessed by capnography monitoring on the chest tube drainage.

Capnography↗
PubMed2002

Monitoring gaseous exchange: implications for nursing care.

The purpose of this study is to examine whether a relationship exists between arterial and end-tidal carbon dioxide tension (PaCO2 and PETCO2 respectively) in patients admitted to intensive care units (ICUs), and what the implications it has for nursing care. PaCO2 and PETCO2 are indicators of ventilatory adequacy which is an important aspect of respiratory function. These measures of carbon dioxide tension are obtained via invasive and non-invasive monitoring tools. Measurement of PETCO2 has only recently been introduced into ICUs and its usefulness in these environments is open to debate. A population of 30 intubated patients had 214 simultaneous measurements of PaCO2 and PETCO2 taken over a period of 10 months. The findings indicate that, despite strong significant correlations, PETCO2 cannot be used safely as a substitute for PaCO2 as the arterial/end-tidal carbon dioxide gradient is not constant, nor does capnography provide a consistently reliable indicator of PaCO2.

Adult↗
PubMed2001

Venous air and gas emboli in operative hysteroscopy.

Air and gas emboli have been reported in almost all areas of clinical and surgical practice. The literature is replete with observations and methods for treating these events. It is possible to mitigate the consequences of this risk, particularly in operative hysteroscopy. Recommendations include monitoring devices such as capnography to facilitate intraoperative diagnosis of these emboli.

Animals↗
PubMed2006

Effects of prone position on alveolar dead space and gas exchange during general anaesthesia in surgery of long duration.

BACKGROUND AND OBJECTIVE: We investigated the effects of prone position on respiratory dead space and gas exchange in 14 anaesthetized healthy patients undergoing elective posterior spinal surgery of more than 3 h of duration. METHODS: The patients received a total intravenous anaesthetic with propofol/remifentanil/cisatracurium. They were ventilated at a tidal volume of 8-10 mL kg(-1), zero positive end-expiratory pressure and an inspired oxygen fraction of 0.4. Physiological, airway and alveolar dead spaces were calculated by analysis of the volumetric capnography waveform. Measurements were made in supine position (20 min after the beginning of mechanical ventilation) and 30, 120 and 180 min after turning to prone position. RESULTS: We found that the alveolar dead space/tidal volume ratio did not change. PaO(2)/F(i)O(2) increased, although not statistically significantly. Dynamic compliance was reduced due to a reduction in tidal volume and an increase in plateau pressure. CONCLUSIONS: Patients undergoing surgery in prone position for a duration of 3 h under general anaesthesia including muscle relaxation and mechanical ventilation without positive end-expiratory pressure have stable haemodynamics and no significant changes in the alveolar dead space to tidal volume ratio. Oxygenation tended to improve.

Anesthesia, General↗
PubMedDate not supplied

Carbon monoxide and nonquantitative carbon dioxide detection.

INTRODUCTION: The capnometric demonstration of end-tidal carbon dioxide (CO2) is a reliable method of differentiating between a correct endotracheal tube position and an accidental misplacement of the tube into the esophagus. Recently, several CO2 detectors have been introduced for monitoring end-tidal CO2 in the "out-of-hospital" setting, where quantitative capnometry with capnography is not yet available. HYPOTHESIS: These devices are not influenced by carbon monoxide (CO) present in lethal concentration. METHODS: A heated (37 degrees C) 2.3 L reservoir bag filled one-third full with water (representing the stomach in esophageal misintubation) was machine ventilated (tidal volume: 450 ml; frequency: 16/min) with the following mixtures for three minutes each: 1) 95% O2, 5% CO; 2) 45% O2, 5% CO, 50% N2O; and 3) 44% O2, 5% CO, 50% N2O, 1% halothane. The presence of end-tidal CO2 was monitored with each of the following devices: 1) MiniCAP III CO2 Detector; 2) StatCAP CO2 Detector; 3) EasyCAP CO2 Detector; 4) PediCAP CO2 Detector; and 5) Colibri CO2 Detector. RESULTS: In none of the cases was the presence of CO2 signaled by the detector. CONCLUSION: The presence of 5% CO does not interfere with infrared spectrometry detection (MiniCAP and StatCAP) or chemical detection (EasyCAP, PediCAP, and Colibri) of CO2. The devices can be used safely in patients with CO poisoning for monitoring of endotracheal tube position.

Capnography↗
PubMed1997

Logistics of conducting a large number of individual sessions with a full-scale patient simulator at a scientific meeting.

OBJECTIVE: To design and implement the logistics of accommodating a large number of participants in individual, hands-on sessions on a full-scale patient simulator during a major scientific meeting or continuing medical education course. METHODS: We used our method during the 11th World Congress of Anaesthesiologists in Sydney, Australia to facilitate studying the impact of pulse oximetry and capnography on the time taken by anesthesiologists to correctly identify critical incidents on a full-scale patient simulator. Each study participant spent 15 minutes in 4 sections of the study area: the anesthesia and monitoring equipment briefing room, the simulator briefing room, the simulation room and the debriefing room. RESULTS: There were 113 participants during five days (15 during instructor training and 25, 23, 24 and 26 on subsequent exhibit days). We were oversubscribed daily. However, there were 9 no-shows during the 4 days of the study, which generated a participant absence rate of 9.2%. The average number of participants over the 4 days of the study was 24.5 per day compared to our capacity of 27 per day. The feedback we obtained from the participants about the simulation experience and the format of the exercise was positive and enthusiastic. CONCLUSIONS: We have developed a practical and viable method that can be adapted for use at scientific meetings and courses, which improves accessibility of individual, hands-on sessions on full-scale patient simulators to a larger audience than previously attainable. Our method is applicable for continuing medical education courses as well as research purposes in the form of prospective studies during scientific meetings and courses.

Anesthesiology↗
PubMed1998

A scoring system for capnogram biofeedback: preliminary findings.

Labored breathing and irregularities in the breathing pattern may be assessed by capnography; and, an abnormal capnogram wave form may often be rectified with the help of capnogram biofeedback. Clinical experience suggests this may relieve dyspnea but to what degree, for how long and for what conditions have not been determined; the issue is complex and much remains to be discovered. The more that can be learned about the various capnogram irregularities, the more effectively such information will guide us in therapy and research. To this end a 15-category capnogram disordered breathing scale (Landis CDBS) was developed to provide a measure of disordered breathing. The CDBS score is the ratio of the total number of abnormal capnogram forms to the total number of capnogram configurations in the test sample, expressed as a percentage. The total score as well as an accounting of each abnormal scoring category was tabulated for each subject. In this retrospective and preliminary study, findings of a normal comparison group were compared with capnogram data for 3 clinical groups: asthma, anxiety/panic attacks, and patients with diverse stress-related somatic symptoms. Mean CDBS scores were: a low 14% for the Normal group compared with 64% for the Asthma group; 66% for the Anxiety patients; and 47% for the Somatic group. Each group was characterized by distinctive clusters of capnogram abnormalities. As there are methodological limitations to this small group study, the findings require validation. However, as an introduction to the scoring system and because of its potential clinical value we present this paper now.

Adult↗
PubMed2005

Hyperventilation and amplified blood pressure response: is there a link?

Based on prior studies, the hypothesis that hyperventilation (HV) may have a pressor effect and play a causal role in hypertension has been suggested. The objective of this study was to correlate HV with blood pressure (BP)-change during a postural challenge. Consecutive subjects referred for evaluation of syncope, dizziness, chronic fatigue syndrome (CFS), fibromyalgia, or non-CFS fatigue were assessed with a 10-min supine 30-min head-up tilt test combined with capnography. We selected for analysis the records of patients aged 17-70 years, not taking vasoactive medications, having sitting systolic BP (SBP) < 140 mmHg, sitting diastolic BP (DBP) < 90 mmHg, and who completed 30 min of tilt. HV was diagnosed when end-tidal pressure of CO2 < 30 mmHg was recorded consecutively for > or = 10 min. Postural hypertension (PHT) was diagnosed when DBP on tilt > or = 90 mmHg was recorded consecutively for > or = 10 min. DBP-change was computed as (median DBP on tilt) -(median DBP supine). PHT and DBP-change were correlated with HV. A total of 320 patient charts were reviewed. PHT was present in 30 cases. The mean DBP-change in patients with PHT was +9.9 mmHg (s.d. 5.8), with three patients manifesting HV. Of the remaining 290 patients, 56 had HV, their mean DBP-change was -0.3 mmHg (s.d. 7.2). The other 234 patients without HV had a mean DBP-change +0.95 mmHg (s.d. 5.7), comparable to the DBP-change in patients with HV. In, conclusion, posturally induced HV was not associated with an increase in BP, nor was PHT associated with HV, except in a small minority of cases.

Adolescent↗
PubMed2003

Calibration of three capnographs for use with helium and oxygen gas mixtures.

Capnography is considered essential in the management of mechanically-ventilated patients. Helium, as an adjunct to mechanical ventilation, is the subject of renewed interest and used increasingly. However, helium affects the performance of infrared capnometry. We constructed a simple device to generate variable mixtures of helium, oxygen and carbon dioxide within the normal physiological range, and tested the performance of two side-stream and one in-line capnographs. We found that addition of helium to the gas mixture caused all three capnographs to underestimate the concentration of carbon dioxide. The underestimation increased as the proportion of helium increased. The maximum underestimation (30%) occurred in a 79:21 helium/oxygen mixture.

Calibration↗
PubMed2001

Noninvasive monitoring of oxygen and carbon dioxide.

Pulse oximetry and capnography are widely used in clinical practice. They provide quick and noninvasive methods to estimate arterial oxygen saturation and carbon dioxide tension in different situations including emergency departments, intensive care units, and during procedures. This article reviews the principles of surgery, accuracy, limitations, and clinical applications of these instruments.

Capnography↗