Continuous Capnography Monitoring Research Articles

Continuous Capnography for Early Detection of Respiratory Compromise During Gastroenterological Procedural Sedation and Analgesia.

Gastroenterology nurses working across a variety of clinical settings are responsible for periprocedural monitoring during moderate to deep procedural sedation and analgesia (PSA) to identify signs of respiratory compromise and intervene to prevent cardiorespiratory events. Pulse oximetry is the standard of care for respiratory monitoring, but it may delay or fail to detect abnormal ventilation during PSA. Continuous capnography, which measures end-tidal CO2 as a marker of alveolar ventilation, has been endorsed by a number of clinical guidelines. Large clinical trials have demonstrated that the addition of continuous capnography to pulse oximetry during PSA for various gastroenterological procedures reduces the incidence of hypoxemia, severe hypoxemia, and apnea. Studies have shown that the cost of adding continuous capnography is offset by the reduction in adverse events and hospital length of stay. In the postanesthesia care unit, continuous capnography is being evaluated for monitoring opioid-induced respiratory depression and to guide artificial airway removal. Studies are also examining the utility of continuous capnography to predict the risk of opioid-induced respiratory depression among patients receiving opioids for primary analgesia. Continuous capnography monitoring has become an essential tool to detect early signs of respiratory compromise in patients receiving PSA during gastroenterological procedures. When combined with pulse oximetry, it can help reduce cardiorespiratory adverse events, improve patient outcomes and safety, and reduce health care costs.

Implementation of Continuous Capnography Protocol in a Postanesthesia Care Unit for Adult Patients at High-risk of Postoperative Respiratory Depression

PurposeThis project aimed to implement a continuous capnography protocol in the postanesthesia care unit (PACU) for postoperative adult patients who are at high risk for respiratory failure. DesignA preintervention and postintervention quality improvement design with retrospective chart reviews evaluated patient demographics (age, weight, body mass index [BMI], perioperative fluid intake and output, use of intraoperative positive-end expiratory pressure), length of surgery, average length of PACU stay, incidence of respiratory events, and adherence to a PACU capnography protocol. MethodsPreimplementation data were collected from retrospective chart reviews over a 3-month period. A continuous capnography protocol was implemented for same-day surgery patients with a BMI of 35 kg/m2 or greater and who received general anesthesia. Postimplementation data were collected over 3 months in addition to adherence to the capnography protocol. This was presented using descriptive statistics. FindingsAge, length of surgery, weight, BMI, perioperative fluid intake and output, and use of positive-end expiratory pressure did not impact PACU length of stay. The average PACU length of stay decreased from 76.76 to 71.82 minutes postimplementation but was not statistically significant (P = .470). The incidence of respiratory events was 6% (n = 3). After the implementation of the continuous capnography protocol, adherence to the continuous capnography monitoring was 86% (n = 43). ConclusionsPatients who are at high risk for postoperative respiratory failure may benefit from continuous capnography monitoring in the PACU. Capnography monitoring may decrease PACU length of stay and provide earlier detection of pending respiratory depression or failure than pulse oximetry alone.

A machine learning algorithm for detecting abnormal patterns in continuous capnography and pulse oximetry monitoring

Continuous capnography monitors patient ventilation but can be susceptible to artifact, resulting in alarm fatigue. Development of smart algorithms may facilitate accurate detection of abnormal ventilation, allowing intervention before patient deterioration. The objective of this analysis was to use machine learning (ML) to classify combined waveforms of continuous capnography and pulse oximetry as normal or abnormal. We used data collected during the observational, prospective PRODIGY trial, in which patients receiving parenteral opioids underwent continuous capnography and pulse oximetry monitoring while on the general care floor [1]. Abnormal ventilation segments in the data stream were reviewed by nine experts and inter-rater agreement was assessed. Abnormal segments were defined as the time series 60s before and 30s after an abnormal pattern was detected. Normal segments (90s continuous monitoring) were randomly sampled and filtered to discard sequences with missing values. Five ML models were trained on extracted features and optimized towards an Fβ score with β = 2. The results show a high inter-rater agreement (> 87%), allowing 7,858 sequences (2,944 abnormal) to be used for model development. Data were divided into 80% training and 20% test sequences. The XGBoost model had the highest Fβ score of 0.94 (with β = 2), showcasing an impressive recall of 0.98 against a precision of 0.83. This study presents a promising advancement in respiratory monitoring, focusing on reducing false alarms and enhancing accuracy of alarm systems. Our algorithm reliably distinguishes normal from abnormal waveforms. More research is needed to define patterns to distinguish abnormal ventilation from artifacts.

Impact of Adoption of Smart Pump System With Continuous Capnography Monitoring on Opioid-Related Adverse Event Rates: Experience From a Tertiary Care Hospital.

ObjectivesThe use of opioid analgesics for pain management in hospitalized patients is associated with a high risk of adverse events, including respiratory depression which may lead to respiratory arrest and death. Patients who experience opioid-related adverse drug reactions (ADRs) have been shown to experience longer and more costly hospital stays and have a higher risk of requiring a readmission after discharge. In this study, we report on the impact of the introduction of Wesley Medical Center's Safe Medication Practice Protocol on opioid-related ADRs.MethodsA retrospective, pre-post cohort study using electronic health records combined with manual chart review was undertaken at the Wesley Medical Center, a 760-bed tertiary care facility. The Safe Medication Practice Protocol incorporating a smart infusion pump system with capnography monitoring was implemented in May 2010 hospital-wide. The number and severity of ADRs and the duration of opioid treatment were compared between the pre (2007-April 2010) and post (May 2010–2014) periods.ResultsA total of 139,734 (pre-period) versus 267,573 (post-period) patients received opioid treatment during the hospital stay. Compared with the pre-period, the post-period resulted in a 79.2% reduction in the number of severe adverse reactions (3.08 vs 0.64 per 10,000 patients treated with opioid, P < 0.0001) as well as a shorter duration of opioid treatment (average 2.05 vs 1.37 days, P < 0.0001).ConclusionsImplementing education, revisions to patient-controlled analgesia policies and procedures, and capnography monitoring with patient-controlled analgesia pause is associated with significantly lower rates of severe ADRs and shorter opioid treatment duration.

Continuous Pulse Oximetry and Capnography Monitoring for Postoperative Respiratory Depression and Adverse Events: A Systematic Review and Meta-analysis.

Death and anoxic brain injury from unrecognized postoperative respiratory depression (PORD) is a serious concern for patient safety. The American Patient Safety Foundation has called for continuous electronic monitoring for all patients receiving opioids in the postoperative period. These recommendations are based largely on consensus opinion with currently limited evidence. The objective of this study is to review the current state of knowledge on the effectiveness of continuous pulse oximetry (CPOX) versus routine nursing care and the effectiveness of continuous capnography monitoring with or without pulse oximetry for detecting PORD and preventing postoperative adverse events in the surgical ward. We performed a systematic search of the literature databases published between 1946 and May 2017. We selected the studies that included the following: (1) adult surgical patients (>18 years old); (2) prescribed opioids during the postoperative period; (3) monitored with CPOX and/or capnography; (4) primary outcome measures were oxygen desaturation, bradypnea, hypercarbia, rescue team activation, intensive care unit (ICU) admission, or mortality; and (5) studies published in the English language. Meta-analysis was performed using Cochrane Review Manager 5.3. In total, 9 studies (4 examining CPOX and 5 examining continuous capnography) were included in this systematic review. In the literature on CPOX, 1 randomized controlled trial showed no difference in ICU transfers (6.7% vs 8.5%; P = .33) or mortality (2.3% vs 2.2%). A prospective historical controlled trial demonstrated a significant reduction in ICU transfers (5.6-1.2 per 1000 patient days; P = .01) and rescue team activation (3.4-1.2 per 1000 patient days; P = .02) when CPOX was used. Overall, comparing the CPOX group versus the standard monitoring group, there was 34% risk reduction in ICU transfer (P = .06) and odds of recognizing desaturation (oxygen saturation [SpO2] <90% >1 hour) was 15 times higher (P < .00001). Pooled data from 3 capnography studies showed that continuous capnography group identified 8.6% more PORD events versus pulse oximetry monitoring group (CO2 group versus SpO2 group: 11.5% vs 2.8%; P < .00001). The odds of recognizing PORD was almost 6 times higher in the capnography versus the pulse oximetry group (odds ratio: 5.83, 95% confidence interval, 3.54-9.63; P < .00001). No studies examined the impact of continuous capnography on reducing rescue team activation, ICU transfers, or mortality. The use of CPOX on the surgical ward is associated with significant improvement in the detection of oxygen desaturation versus intermittent nursing spot-checks. There is a trend toward less ICU transfers with CPOX versus standard monitoring. The evidence on whether the detection of oxygen desaturation leads to less rescue team activation and mortality is inconclusive. Capnography provides an early warning of PORD before oxygen desaturation, especially when supplemental oxygen is administered. Improved education regarding monitoring and further research with high-quality randomized controlled trials is needed.

Continuous Capnography Reduces the Incidence of Opioid-Induced Respiratory Rescue by Hospital Rapid Resuscitation Team.

The aim of this study was to determine the impact of end tidal carbon dioxide or capnography monitoring in patients requiring patient-controlled analgesia (PCA) on the incidence of opioid-induced respiratory depression (OIRD) in the setting of rapid response. A retrospective analysis was conducted in an urban tertiary care facility on the incidence of OIRD in the setting of rapid response as defined by a positive response to naloxone from January 2012 to December 2015. In March 2013, continuous capnography monitoring was implemented for all patients using PCA. The preintervention incidence of OIRD in the setting of rapid response was 0.4% of patients receiving opioids. After the implementation of capnography, the incidence of OIRD in the setting of rapid response was reduced to 0.2%, which was statistically significant (χ2 = 46.246; df, 1; P < 0.0001). The rate of transfers to a higher level of care associated with these events was also reduced by 79% (baseline, 7.6 transfers/month; postintervention, 1.6 transfers/month). Continuous capnography monitoring in patients receiving PCA significantly reduces the incidence of OIRD in the setting of rapid response and unplanned transfers to a higher level of care.

Research: Continuous Surveillance of Sleep Apnea Patients in a Medical-Surgical Unit.

This report consists of two separate studies on the use of continuous capnography monitoring conducted in an effort to improve patient safety at Virtua Health System. The desire for improved patient safety is motivating continuous monitoring and improved surveillance in clinical areas not traditionally equipped for such monitoring. We explored the use of remote monitoring of capnography, using enterprise middleware, in patients recovering from surgery in a medical-surgical unit. Continuous monitoring traditionally has been used in higher-acuity settings, such as intensive care units. Patients diagnosed or suspected to have obstructive or central sleep apnea may benefit from the increased surveillance afforded by continuous monitoring. Pain management in this cohort of patients, recovering from bariatric, joint replacement, or other major surgery, often involves administration of opioids (e.g., hydromorphone, morphine sulfate), which are known to increase risk of respiratory depression. Continuous monitoring of these patients increases the likelihood of detecting adverse clinical events. Our goal was to implement continuous monitoring in order to identify alarm conditions caused by adverse clinical events requiring intervention (e.g., opioid-induced respiratory depression) and artifacts related to patient movement, suspect measurements, or other medical device-generated alarm signals.

Continuous capnography monitoring during resuscitation in a transitional large mammalian model of asphyxial cardiac arrest.

In neonates requiring chest compression (CC) during resuscitation, neonatal resuscitation program (NRP) recommends against relying on a single feedback device such as end-tidal carbon dioxide (ETCO2) or saturations (SpO2) to determine return of spontaneous circulation (ROSC) until more evidence becomes available. We evaluated the role of monitoring ETCO2 during resuscitation in a lamb model of cardiac arrest induced by umbilical cord occlusion (n = 21). Lambs were resuscitated as per NRP guidelines. Systolic blood pressure (SBP), carotid and pulmonary blood flows along with ETCO2 and blood gases were continuously monitored. Resuscitation was continued for 20 min or until ROSC (whichever was earlier). Adequate CC was arbitrarily defined as generation of 30 mmHg SBP during resuscitation. ETCO2 thresholds to predict adequacy of CC and detect ROSC were determined. Significant relationship between ETCO2 and adequate CC was noted during resuscitation (AUC-0.735, P < 0.01). At ROSC (n = 12), ETCO2 rapidly increased to 57 ± 20 mmHg with a threshold of ≥32 mmHg being 100% sensitive and 97% specific to predict ROSC. In a large mammalian model of perinatal asphyxia, continuous ETCO2 monitoring predicted adequacy of CC and detected ROSC. These findings suggest ETCO2 in conjunction with other devices may be beneficial during CC and predict ROSC.

Difficult airway management resources and capnography use in Japanese intensive care units: a nationwide cross-sectional study.

PurposeThe availability of difficult airway management (DAM) resources and the extent of capnometry use in Japanese intensive care units (ICUs) remained unclear. The purpose of this study was to clarify whether: (1) DAM resources were adequate, and (2) capnometry was routinely applied in Japanese ICUs.MethodsThis nationwide cross-sectional study was conducted from September 2015 to February 2016. All ICUs received a mailed questionnaire about their DAM resources and use of capnometry. Outcome measures were availability of: (1) 24-h in-house backup coverage; (2) a supraglottic airway device (SGA); (3) a dedicated DAM cart; and (4) surgical airway devices, and (5) routine use of capnometry to verify tube placement and for continuous monitoring of ventilator-dependent patients. The association between these outcomes and ICU type (academic, high-volume, closed, surgical) was also analyzed.ResultsOf the 289 ICUs, 196 (67.8 %) returned completed questionnaires. In-house backup coverage and surgical airway devices were highly available (89.3 and 95.9 %), but SGAs and dedicated DAM carts were not (60.2 and 60.7 %). The routine use of capnometry to confirm tube placement was reported by 55.6 % of the ICUs and was highest in closed ICUs (67.2 %, p = 0.03). The rate of continuous capnography monitoring was also 55.6 % and was highest in academic ICUs (64.5 %, p = 0.04).ConclusionIn Japanese ICUs, SGAs and dedicated DAM carts were less available, and capnometry was not universally applied either to confirm tube placement, or for continuous monitoring of ventilated patients. Our study revealed areas in need of improvement.Electronic supplementary materialThe online version of this article (doi:10.1007/s00540-016-2176-3) contains supplementary material, which is available to authorized users.

Continuous End-Tidal Carbon Dioxide Monitoring during Resuscitation of Asphyxiated Term Lambs

Background: The Neonatal Resuscitation Program (NRP) recommends close monitoring of oxygenation during the resuscitation of newborns using a pulse oximeter. However, there are no guidelines for monitoring carbon dioxide (CO₂) to assess ventilation. Considering that cerebral blood flow (CBF) correlates directly with PaCO₂, continuous capnography monitoring of end-tidal CO₂ (ETCO₂) may limit fluctuations in PaCO₂ and, therefore, CBF during resuscitation of asphyxiated infants. Objective: To evaluate whether continuous monitoring of ETCO₂ with capnography during resuscitation of asphyxiated term lambs with meconium aspiration will prevent fluctuations in PaCO₂ and carotid arterial blood flow (CABF). Methods: Fifty-four asphyxiated term lambs with meconium aspiration syndrome were mechanically ventilated from birth to 60 min of age. Ventilatory parameters were adjusted based on clinical observation (chest excursion) and frequent arterial blood gas analysis in 24 lambs (control group) and 30 lambs (capnography group) received additional continuous ETCO₂ monitoring. Left CABF was monitored. We aimed to maintain PaCO₂ between 35 and 50 mm Hg and ETCO₂ between 30 and 45 mm Hg. Results: There was a significant correlation between ETCO₂ and PaCO₂ (R = 0.7, p < 0.001), between PaCO₂ and carotid flow (R = 0.52, p < 0.001) and between ETCO₂ and carotid flow (R = 0.5, p < 0.001). PaCO₂ and CABF during the first 60 min of age showed significantly higher fluctuation in the control group compared to the capnography group. Conclusion: Continuous monitoring of ETCO₂ using capnography with mechanical ventilation during and after resuscitation in asphyxiated term lambs with meconium aspiration limits fluctuations in PaCO₂ and CABF and may potentially limit brain injury.

Implementation of continuous capnography is associated with a decreased utilization of blood gases.

BackgroundCapnography provides a continuous, non-invasive monitoring of the CO2 to assess adequacy of ventilation and provide added safety features in mechanically ventilated patients by allowing for quick identification of unplanned extubation. These monitors may allow for decreased utilization of blood gases. The objective was to determine if implementation of continuous capnography monitoring decreases the utilization of blood gases resulting in decreased charges.MethodsThis is a retrospective review of a quality improvement project that compares the utilization of blood gases before and after the implementation of standard continuous capnography. The time period of April 2010 to September 2010 was compared to April 2011 to September 2011. Parameters collected included total number of blood gases analyzed, cost of blood gas analysis, ventilator and patient days.ResultsThe total number of blood gases after the institution of end tidal CO2 monitoring decreased from 12,937 in 2009 and 13,171 in 2010 to 8,070 in 2011. The average number of blood gases per encounter decreased from 20.8 in 2009 and 21.6 in 2010 to 13.8 post intervention. The blood gases per ventilator day decreased from 4.94 in 2009 and 4.76 in 2010 to 3.30 post intervention. The total charge savings over a 6-month period was $880,496.ConclusionsContinuous capnography resulted in a significant savings over a 6-month period by decreasing the utilization of blood gas measurements.

Algorithm for management of tracheostomy emergencies on intensive care

We congratulate McGrath and colleagues on producing the multidisciplinary guidelines for the management of tracheostomy and laryngectomy airway emergencies 1. An enormous amount of time and effort has clearly gone into producing these; bringing together so many different parties and producing a unified set of guidelines is extremely impressive. Use of these guidelines can be expected to improve significantly the safety of patients with a tracheostomy on our wards. We support the use of signs to indicate the type of tracheostomy, are currently introducing the green (potentially patent upper airway) and red (‘neck breather’) bed-head signs on our intensive care unit (ICU), and our ENT colleagues are currently introducing these guidelines, in full, on our wards. However, whilst we feel that these guidelines will be extremely useful for ward patients, we do have some reservations about using the algorithms for tracheostomy emergencies in our ICU. Tracheostomy emergencies in ward patients are usually related to blockage of a tracheostomy: such a ward patient is unlikely to have continuous capnography monitoring, is often not oxygen dependent, is usually self-ventilating and may well have a mature stoma. Conversely, tracheostomy emergencies in patients on ICU patients usually involve displacement of a tracheostomy in a patient who would usually have continuous capnography monitoring, be oxygen and ventilator dependent and have a recently formed stoma 2-4. For these reasons we feel that ward and ICU patients are quite different and warrant different algorithms. Over the past two years, we have developed an algorithm to guide the management of tracheostomy emergencies on ICU (Fig. 5). As continuous capnography is now so widely recommended for patients dependent on an artificial airway that it should be routine 2-5, our algorithm emphasises the importance of capnography in making the initial diagnosis of a problem with ventilation. It is colour coded to create two pathways: the yellow boxes are designed to enable our nurses and junior trainees to initiate management, and the blue boxes target senior trainees and consultants who may arrive later and who may have additional skills. We use these algorithms regularly in multidisciplinary ‘in-situ’ simulation sessions on our ICU, and our staff report that they are easy to follow. We have had a number of displaced and partially displaced tracheostomies on our ICU over the past two years, all managed using these guidelines, with excellent outcome and no harm to the patients involved. While we genuinely welcome McGrath et al.'s initiative, we suggest that ICU cases are likely to be different in nature and have different needs from ward cases. The importance of capnography in diagnosing the problem and the need for advanced anaesthetic skills to re-establish the airway differentiate the algorithms. Finally, we emphasise that this algorithm is always under review, and would welcome any comments on how it might be improved. We are in the process of developing a second algorithm, to be used in patients who have had a laryngectomy (‘neck breathers’).

A Randomized Double-Blind Controlled Trial of Microstream Capnography to Reduce Oxygen Desaturation During Gastrointestinal Procedures with Conscious Sedation

Oxygen desaturation is a relatively late sign of ventilatory compromise. ASGE monitoring guidelines for all GI procedures call for continuous pulse oximetry and visual assessment during conscious sedation (CS), which may not detect apnea until O2 desaturation has occurred. Microstream capnography may provide an “early warning system” by generating real-time waveforms of respiration (capnograms) in non-intubated patients. Aim: To determine whether intervention based on capnography indications of apnea reduces O2 desaturation during CS. Methods: We performed an IRB-approved double-blind randomized controlled trial of ASA Class I/II children undergoing GI procedures with midazolam + fentanyl CS, 2L supplemental O2, standard patient monitoring, and routine care. Endoscopy staff was blinded to additional continuous capnography monitoring (Philips M4 with Microstream® CO2). Study arm was determined by opening a pre-numbered sequence of envelopes containing randomly permuted assignments. In the intervention arm, a trained independent monitor (IM) signaled to the endoscopy staff by raised hand if capnograms indicated apnea for >15 sec. In the control arm, an IM signaled if capnograms indicated apnea for >60 sec. Upon IM signals, endoscopy RNs instructed patients to breathe deeply and/or touched their backs. We hypothesized that patients randomized to the intervention arm would have fewer episodes of minor O2 desaturation (O2 sats <95% for 5 sec) than patients in the control arm. Results: 163 participants (89 male; mean age 13 yr, range 6mo-19 yr; 86% ASA I) underwent 174 procedures (80% EGD, 13% colonoscopy, 7% both). Intervention and control patients did not differ significantly in sex, age, ASA class, procedures undergone, baseline O2 sats, or doses of midazolam and fentanyl. Endoscopy RNs documented poor ventilation in 2.7% of study patients and no apnea. Capnography indicated disordered ventilation during 56% of all procedures and apnea in 24%. Patients in the intervention arm were significantly less likely to have an intraprocedural episode of O2 desaturation than those in the control arm (11% vs 24%, p < 0.03). Conclusions: The results of this controlled effectiveness trial support the routine use of microstream capnography to improve detection of apnea and reduce O2 desaturation during CS for GI procedures. Supported by AHRQ (K08 HS1-367502), a Risk Management Foundation Patient Safety Grant and Children's Hospital Boston GCRC (M01-RR02172). Oxygen desaturation is a relatively late sign of ventilatory compromise. ASGE monitoring guidelines for all GI procedures call for continuous pulse oximetry and visual assessment during conscious sedation (CS), which may not detect apnea until O2 desaturation has occurred. Microstream capnography may provide an “early warning system” by generating real-time waveforms of respiration (capnograms) in non-intubated patients. Aim: To determine whether intervention based on capnography indications of apnea reduces O2 desaturation during CS. Methods: We performed an IRB-approved double-blind randomized controlled trial of ASA Class I/II children undergoing GI procedures with midazolam + fentanyl CS, 2L supplemental O2, standard patient monitoring, and routine care. Endoscopy staff was blinded to additional continuous capnography monitoring (Philips M4 with Microstream® CO2). Study arm was determined by opening a pre-numbered sequence of envelopes containing randomly permuted assignments. In the intervention arm, a trained independent monitor (IM) signaled to the endoscopy staff by raised hand if capnograms indicated apnea for >15 sec. In the control arm, an IM signaled if capnograms indicated apnea for >60 sec. Upon IM signals, endoscopy RNs instructed patients to breathe deeply and/or touched their backs. We hypothesized that patients randomized to the intervention arm would have fewer episodes of minor O2 desaturation (O2 sats <95% for 5 sec) than patients in the control arm. Results: 163 participants (89 male; mean age 13 yr, range 6mo-19 yr; 86% ASA I) underwent 174 procedures (80% EGD, 13% colonoscopy, 7% both). Intervention and control patients did not differ significantly in sex, age, ASA class, procedures undergone, baseline O2 sats, or doses of midazolam and fentanyl. Endoscopy RNs documented poor ventilation in 2.7% of study patients and no apnea. Capnography indicated disordered ventilation during 56% of all procedures and apnea in 24%. Patients in the intervention arm were significantly less likely to have an intraprocedural episode of O2 desaturation than those in the control arm (11% vs 24%, p < 0.03). Conclusions: The results of this controlled effectiveness trial support the routine use of microstream capnography to improve detection of apnea and reduce O2 desaturation during CS for GI procedures. Supported by AHRQ (K08 HS1-367502), a Risk Management Foundation Patient Safety Grant and Children's Hospital Boston GCRC (M01-RR02172).