Application Of Capnography Research Articles

Applications of capnography in airway management outside the operating room

The capnograph is vital for patient monitoring in the operating room. Its clinical applications for airway management outside the operating room are being increasingly recognized due to its role in the Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Guidelines. Capnography can be used for the detection of respi-ratory depression during procedural sedation, verification after emergency endotracheal tube intubation, assessment of the airway and circulation during cardiopulmonary resuscitation, and continuous monitoring during patient transportation and in intensive care settings. This can be especially beneficial for pediatric patients, those who are critically ill, and patients with a difficult airway.

Capnography monitoring in procedural intravenous sedation: a systematic review and meta-analysis.

Currently, procedural sedation in the clinical setting relies heavily on the use of pulse oximetry to monitor hypoxemia. Different studies suggest that incidence of hypoxemia and incidence of arterial oxygen desaturation are reduced by early intervention via capnography monitoring. The aim of this article was to discuss the importance of implementing capnography monitoring during procedural sedations performed in a dental setting and determine whether additional capnographic monitoring reduces the incidence of arterial oxygen desaturation and the overall complications rate. Two independent reviewers conducted electronic (PubMed and EMBASE) and manual searches up to February 2020. Randomized clinical trials (RCTs), including both patients under procedural sedation monitored by capnography and oximetry, and reporting the incidence of hypoxemia or episodes of oxygen desaturation were included. Risk ratio was used to compare the outcomes (i.e., the incidence of hypoxemia, the episodes of oxygen desaturation, the detection of apnea, the reduction of events of bradycardia, and hypotension) between patients monitored by capnography and standard approach. Fourteen randomized clinical trials fulfilling the inclusion criteria were selected. The analysis revealed that capnography monitoring group showed the lower incidence of hypoxemia (RR 0.76, 95%CI 0.70 to 0.83, p < 0.001) and the episodes of oxygen desaturation (RR 0.79, 95%CI 0.71 to 0.87, p < 0.001) compared with the oximetry monitoring group. Apnea was detected in capnography monitoring earlier than standard monitoring (RR 2.60, 95%CI 2.30 to 2.93, p < 0.001). No significant difference was found between capnography and standard monitoring groups in terms of reduction of events of bradycardia (RR 1.17, 95%CI 0.91 to 1.50, p = 0.225) and hypotension (RR 0.96, 95%CI 0.76 to 1.21, p = 0.746). Capnography monitoring reduced incidence of hypoxemia during procedural sedations. Within the limitations of this review, we suggest that the application of capnography during procedural sedation would decrease the frequency of oxygen desaturation events and incidence of hypoxemia. Training and instructing dental providers on using capnography monitoring would help in reducing adverse events during intravenous sedation.

Applicability of Capnography in the Adult ICU During Physical Therapy: A Systematic Review

PurposeThe purpose of this review was three‐fold: first, evaluate the strength and quality of the current research evidence on usage of capnography, second, determine whether current evidence regarding the use capnography during physical therapy should be considered when making decisions regarding patient’s response to physical therapy; and third, identify weaknesses in the current evidence and area for continued research.Background/SignificanceCapnography is typically used in emergency departments and postoperatively but is not commonly used during physical therapy. Pulse oximetry is typically used to monitor oxygen desaturation and hypoxemia during physical therapy but does not predict or monitor respiratory depression. Capnography monitoring during exercise and mobility could have benefits for physical therapists monitoring patients during therapy as well as provide prognostic value of patient progress.Methods and MaterialsA literature search was completed using: Science Direct, IOP Science, PLOS one, Google scholar, Wiley, EBSCO Host, CINAHL Complete, Cochrane Library, and PubMed. Keywords: capnometry, capnography accuracy, physical therapy, application of capnography, mobility, monitoring. Articles selected for review were those of original research or systematic review published since 2009 and evaluated for quality using the Oxford Centre for Evidence‐Based Medicine 2011 levels of evidence system.ResultsTwenty‐seven articles are included for this study. Six articles were included in the introduction. Seven articles examined the current practices for use of capnography; six studies looked at the use of capnography in the intensive care unit. Three articles on pulse oximetry and capnography with mobility, two articles on the use of monitoring ventilation and oximetry during exercise, and three studies on biologically‐based assessment tools for physical therapy.ConclusionsEvidence suggests that monitoring partial pressure end‐tidal carbon dioxide (PETCO2) levels in patients during rest and exercise may provide more prognostic value of possible adverse events in patients with conditions such as heart failure. Monitoring ventilatory responses in patients is valuable in physical therapy as it indicates tolerance to activity. Evidence suggests there is a significant correlation between PETCO2 and cardiac output. Recent research also suggests regardless of mask or cannula used on patients, diagnostic accuracy of measuring PETCO2 is similar during normal and hyper‐ventilatory states. With increasing application of capnography in intensive care settings, studies involving usage in physical therapy are warranted.

Utility of end-tidal carbon dioxide monitoring in critically ill children.

Carbon dioxide is produced in the tissues as a byproduct of aerobic metabolism, then transported to the lungs by the venous circulation and is finally eliminated during the expiratory phase of ventilation. End-tidal CO2(ETCO2) is defined as the peak CO2 value during expiration and is dependent on adequate pulmonary blood flow to the ventilating areas of the lung. ETCO2 in healthy subjects differs normally by <5 mmHg from the arterial CO2(PaCO2). An increased ETCO2-PaCO2 gap can be found in association with a decreased pulmonary blood flow and/or increased dead-space. Capnometry is the measurement of CO2 concentration of tidal gas at the airway opening. Capnography is the graphic display of the measured CO2. Capnography is an important non-invasive technique that can monitor CO2 production, pulmonary perfusion and alveolar ventilation as well as respiratory patterns.[1] Capnography has been shown to be effective as a tool for early detection of complications during anesthesia including, hypoventilation, esophageal intubation and circuit disconnection. Tinker et al.[2] concluded after a closed claim analysis for the American Society of Anesthesiology that the application of capnography and pulse oximetry together could have helped prevent 93% of avoidable anesthesia mishaps identified in their study. Capnometry is now a standard of care during administration of general anesthesia, for confirmation of placement of endotracheal tube after intubation and during transportation of an intubated patient. It has been increasingly used in intubated ventilated patients in intensive care units to safely wean patients, decrease the number of arterial blood gases, detect endotracheal displacement and prevent hypercarbia. Nasal ETCO2 monitoring is useful during procedural sedation and post-operative monitoring in the recovery room. In addition, volumetric capnography can be used as a non-invasive method to measure cardiac output. In this journal, Mehta and colleagues presented their data showing good correlation between ETCO2 and PaCO2 in neonates and children.[3] As expected correlation between ETCO2 and PaCO2 was weaker when P/F ratio was 200. Although, the mean bias with the Bland-Altman plot was low in neonates as well as children the limits of agreement is large suggesting variability of PaCO2-ETCO2 gap in their sample. Their findings confirm previously published data in neonates. The gradient between PaCO2 and ETCO2 depends upon the amount of dead space during ventilation.[4] Many variables influence the percentage of dead space to total minute ventilation. Decreased pulmonary blood flow, pulmonary disease or hyperinflation of lungs can lead to increased dead space and consequently high PaCO2-ETCO2 gap. An important limitation of using ETCO2 as a surrogate for PaCO2 measurement is that the PaCO2-ETCO2 gap changes from patient to patient based on underlying pulmonary and cardiovascular conditions and ventilation strategies and within the same patient with significant changes in the cardiopulmonary condition. In a stable patient ETCO2 monitoring can be used as trending tool during weaning or after the change in ventilator setting. Periodic measurement of PaCO2 is necessary to make sure the PaCO2-ETCO2 gap is not significantly altered. Mehta et al.[3] confirmed previous reports of ETCO2 monitoring as a valid tool in sick, mechanically ventilated neonates and children. In addition to monitoring ventilation status, continuous ETCO2 is useful in early detection of dislodgement of endotracheal tube. Waveform of capnography may be useful in detecting certain type of pulmonary pathology, such as obstructive airway disease. ETCO2 monitoring is a valuable tool during cardiopulmonary resuscitation (CPR). ETCO2 levels fall to low levels at the onset of cardiac arrest, increases with effective CPR and returns to normal levels at return of spontaneous circulation. Although there are no absolute contraindications of use of ETCO2 monitoring there few limitations for its use.[5] Large main stream capnometers can add dead space and may cause kinking of endotracheal tubes. Fortunately, most modern capnometers add a small amount dead space and are of light weight. Gas sampling rate from a side stream capnometer can lead to auto triggering and sometimes inadequate tidal volume delivery in very small neonates. Secretions and condensation in the tubing and leaks in the ventilator circuit can affect the accuracy of ETCO2. End-tidal carbon dioxide monitoring is a useful tool in the management of acutely ill and is becoming a standard of care in many clinical situations. In ventilated patients, ETCO2 monitoring is best used as a trending device for ventilation in addition to detecting endotracheal position.

Potential applications of capnography in the prehospital setting

End-tidal carbon dioxide (ETCO2) monitoring is well established in hospital theatre and critical care settings ( Lah and Grmec, 2010 ), employed for observation and monitoring in anaesthesia. Its application has now extended to the prehospital environment, primarily for the verification of endotracheal tube (ETT) placement, endeavouring to reduce the occurrence of oesophageal intubations ( Grmec and Malley, 2004 ). In recent times, technological advances, coupled with an increased appreciation of the importance of prehospital interventions, has resulted in the production of additional equipment capable of monitoring ETCO2 in non-intubated, self-ventilating patients via a non-invasive nasal cannula. Despite having an extensive range of potential uses, the apparatus is widely underused ( Langhan and Chen, 2008 ). In this article, potential applications in the prehospital setting will be discussed via a review of contemporary literature.

A novel application of capnography during controlled human exposure to air pollution

BackgroundThe objective was to determine the repeatability and stability of capnography interfaced with human exposure facility.MethodsCapnographic wave signals were obtained from five healthy volunteers exposed to particle-free, filtered air during two consecutive 5 min intervals, 10 min apart, within the open and then the sealed and operational human exposure facility (HEF). Using a customized setup comprised of the Oridion Microcap® portable capnograph, DA converter and AD card, the signal was acquired and saved as an ASCII file for subsequent processing. The minute ventilation (VE), respiratory rate (RR) and expiratory tidal volume (VTE) were recorded before and after capnographic recording and then averaged. Each capnographic tracing was analyzed for acceptable waves. From each recorded interval, 8 to 19 acceptable waves were selected and measured. The following wave parameters were obtained: total length and length of phase II and III, slope of phase II and III, area under the curve and area under phase III. In addition, we recorded signal measures including the mean, standard deviation, mode, minimum, maximum – which equals end-tidal CO2 (EtCO2), zero-corrected maximum and true RMS.ResultsStatistical analysis using a paired t-test for means showed no statistically significant changes of any wave parameters and wave signal measures, corrected for RR and VTE, comparing the measures when the HEF was open vs. sealed and operational. The coefficients of variation of the zero-corrected and uncorrected EtCO2, phase II absolute difference, signal mean, standard deviation and RMS were less than 10% despite a sub-atmospheric barometric pressure, and slightly higher temperature and relative humidity within the HEF when operational.ConclusionWe showed that a customized setup for the acquisition and processing of the capnographic wave signal, interfaced with HEF was stable and repeatable. Thus, we expect that analysis of capnographic waves in controlled human air pollution exposure studies is a feasible tool for characterization of cardio-pulmonary effects of such exposures.

Quantitative analysis of end-tidal carbon dioxide during mechanical and spontaneous ventilation in infants and young children.

Capnography provides a substitute for monitoring of arterial carbon dioxide tension (PCO(2)). We performed a prospective study to evaluate a new application of capnography, using quantitative curve analysis in the pediatric ICU. Twenty-five infants and children admitted to the pediatric ICU after cardiovascular surgery for congenital heart diseases were included in the study. Capnographic curves were recorded during 3 phases of mechanical and spontaneous ventilation: phase 1, immediate postoperative period; phase 3, preextubation period; and phase 2, period between phases 1 and 3. Each recording included 17 sec of capnographic tracings from consecutive spontaneous and/or ventilator-driven breaths. Quantitative curve analysis was made to define parameters including peak value of exhaled PCO(2) (P), mean rate of rise of PCO(2) (R), and area under each capnographic curve (A). Qualitative inspection of the wave contour showed no obvious difference in phase 3 during spontaneous and mechanically assisted ventilator breaths. However, an obvious difference existed between spontaneous and mechanically assisted breaths in phase 2. For each parameter (P, R, and A), there was a significant difference in phases 2 and 3 from spontaneous breaths. However, there was no significant difference in phases 2 and 3 from ventilator-assisted breaths. We further calculated the ratio of parameters of spontaneous breaths (S) and ventilator-assisted breaths (V) in phase 2 and phase 3. The ratio of S/V for P, R, and A showed significant differences between phase 2 and phase 3. We conclude that quantitative analysis of exhaled end-tidal PCO(2) curves revealed significant changes of specific parameters during the transition from the ventilator-dependent state to the spontaneously breathing ventilator-independent state. This new approach provides a new way to estimate respiratory status in infants and children receiving ventilator therapy. Through quantitative capnographic curve analysis, if P, R, and A from spontaneous breaths approached those of ventilator-assisted breaths, patients have resumed reasonable pulmonary mechanics, and extubation may then be considered.

Initiation of capnography in a rural ems system

Objective. Capnography is an effective means of monitoring cardiopulmonary resuscitation and managing endotracheal intubation. Numerous studies have validated its use in urban settings, but none have described its integration into a rural EMS system. The authors describe the process of integrating capnography training and use in Jackson County, West Virginia. Methods. Two CO2SMOS capnography/ pulse oximeters were placed on the lead ambulances in Jackson County, West Virginia. Training in the operation and application of the equipment was provided, and providers used the monitors for a period of six months. A questionnaire was administered to assess their understanding of the equipment and its utility in prehospital care. Results were compiled and summarized. Results. Ninety percent of the EMS providers subjectively felt that they understood capnography and its clinical application. They answered questions designed to test their understanding with 65% accuracy. Conclusion. In this model, capnography was successfully integrated into a rural EMS system. Reasonable proficiency in the use of the CO2SMOS monitor and an understanding of the information obtained were demonstrated, although the EMS providers tended to overestimate their actual understanding of the clinical application of capnography. This supports the need for ongoing, targeted education. The authors feel that capnography provides information that is uniquely relevant in rural EMS systems.

Monitoring during Mechnical Ventilation

Monitoring is a continuous, or nearly continuous, evaluation of the physiological function of a patient in real time to guide management decisions, including when to make therapeutic interventions and assessment of those interventions. Pulse oximeters pass two wavelengths of light through a pulsating vascular bed and determine oxygen saturation. The accuracy of pulse oximetry is about ±4%. Capnography measures carbon dioxide at the airway and displays a waveform called the capnogram. End-tidal PCO2represents alveolar PCO2and is determined by the ventilation-perfusion quotient. Use of end-tidal PCO2as an indication of arterial PCO2is often deceiving and incorrect in critically ill patients. Because there is normally very little carbon dioxide in the stomach, a useful application of capnography is the detection of esophageal intubation. Intra-arterial blood gas systems are available, but the clinical impact and cost effectiveness of these is unclear. Mixed venous oxygenation (PvO2or SvO2) is a global indicator of tissue oxygenation and is affected by arterial oxygen content, oxygen consumption and cardiac output. Indirect calorimetry is the calculation of energy expenditure and respiratory quotient by the measurement of oxygen consumption and carbon dioxide production. A variety of mechanics can be determined in mechanically ventilated patients including resistance, compliance, auto-peak end-expiratory pressure (PEEP) and work of breathing. The static pressure-volume curve can be used to identify lower and upper infection points, which can be used to determine the appropriate PEEP setting and to avoid alveolar overdistension. Although some forms of monitoring have become a standard of care during mechanical ventilation (eg, pulse oximetry), there is little evidence that use of any monitor affects patient outcome.

38. A new application of capnography in the field of fatigue

38. A new application of capnography in the field of fatigue