Noninvasive capnometry monitoring for respiratory status during pediatric seizures

The Relation of End-Tidal CO 2 Values With Infarct Volume and Early Prognosis in Patients With Acute Ischemic Stroke

BACKGROUND

The aim of this study is to reveal the relationship between end-tidal CO 2 (EtCO 2 ) values with infarct volume and early prognosis in patients diagnosed with acute ischemic stroke in the emergency department.

MATERIALS AND METHODS

This prospective cross-sectional study was conducted in a tertiary hospital. The demographics, characteristics, EtCO 2 , volume of the stroke area on diffusion-weighted magnetic resonance imaging and the modified Rankin Scale (mRS) of the patients were recorded. The values calculated at admission and at discharge were labeled as "mRS-1" and "mRS-2," respectively, and the mRS-2 measurement was used as a prognostic indicator. The "good" and the "poor" functional outcomes were defined as mRS ≤2 and mRS >2, respectively. Correlations between levels of EtCO 2 and infarct volume, mRS were calculated.

RESULTS

In total, 44 patients were included in the study. The median age of the patients was 69 years (interquartile range; 16; min-max: 35 to 88 y) and 68.2% of them were male. In the univariate logistic regression models of the mRS-2 [0 to 2 (0) and 3 to 6 (1)], all variables were not statistically significant to predict mRS-2 group. There were statistically significant differences in EtCO 2 values between mRS-1 ( P =0.03) and mRS-2 ( P =0.04). A negative moderate correlation was found between EtCO 2 and mRS-2 ( r =-0.410; P =0.006). The correlation between EtCO 2 and infarct volume was not statistically significant ( r =-0.256; P =0.093).

CONCLUSIONS

This study highlights the importance of capnography follow-up of patients with acute ischemic stroke. In patients with acute ischemic stroke, the EtCO 2 value measured at the time of admission is lower in the group with high mRS at both admission and discharge.

Can Non-Invasive Capnography and Integrated Pulmonary Index Contribute to Patient Monitoring in the Pediatric Emergency Department?

OBJECTIVES

Noninvasive capnography (NICG) devices can measure oxygen saturation, end-tidal carbon dioxide (EtCO2), respiratory rate, heart rate values and integrated pulmonary index (IPI). This study aimed to evaluate patients who were monitored using NICG for various indications in a pediatric emergency department and to determine its contribution to patient management in the pediatric emergency department (PED).

METHODS

In this study, children aged <18 years who had been monitored with a NICG at the PED in our university between August 2018-May 2019 were evaluated. Of them 48 patients' file records and monitored capnography parameters such as heart rate, respiratory rate, blood pressure, capillary refill time, Glasgow Coma Score, SpO2, EtCO2, IPI recorded in the forms were reviewed.

RESULTS

Patients most often presented to the emergency room due to seizures (35.4%), change in consciousness (22.9%), other neurological reasons (18.8%) with %50 were female. Seizure treatment(16.7%), circulatory-respiratory support(16.7%), and antiedema treatments(6.3%) were required for 39.5% patients as life-saving interventions, and 72.9% patients were hospitalized. Patients with low IPI(<8) values at the beginning and decreasing IPI (<8) measurements within monitoring period needed more life-saving treatments(p=0.005 and p=0.001, respectively). Low IPI values of the patients during monitoring showed a significant difference in the decision to be hospitalized(p=0.048).

CONCLUSIONS

The results of the present study indicate that monitoring with NICG in the pediatric emergency room can be an important early indicator in establishing clinical prediction. The study particularly points out that the IPI value can be a guide in decisions regarding life-saving treatment and hospitalization. Among the capnographic data of these patients who had a change in consciousness IPI values those measured at the beginning and within the monitorizarion period showed a significant correlation with low GCS (<8) (r=0.478, p=0.001 and r=0.456, p=0.02, respectively). Prospective comprehensive large scale studies are needed to examine the use of NICG and IPI in routine PED practice for various indications.

[Paediatric Life Support]

The European Resuscitation Council (ERC) Paediatric Life Support (PLS) guidelines are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations of the International Liaison Committee on Resuscitation (ILCOR). This section provides guidelines on the management of critically ill or injured infants, children and adolescents before, during and after respiratory/cardiac arrest.

European Resuscitation Council Guidelines 2021: Paediatric Life Support

These European Resuscitation Council Paediatric Life Support (PLS) guidelines, are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the management of critically ill infants and children, before, during and after cardiac arrest.

An Update on End-Tidal CO2 Monitoring

End-tidal CO2 (ETCO2) monitoring is not a new modality in the pediatric emergency department (PED) and emergency department. It is the standard of care during certain procedures such as intubations and sedations and can be used in variety of clinical situations. However, ETCO2 may be underused in the PED setting. The implementation of ETCO2 monitoring may be accomplished many ways, but a foundation of capnography principles specifically in ventilation, cardiac output, and current literature regarding its application is essential to successful implementation. It is the intention of this article to briefly review the principles of ETCO2 monitoring and its clinical applications in the PED setting.

Comparison of nalbuphine and sufentanil for colonoscopy: A randomized controlled trial

OBJECTIVES

Nalbuphine is as effective as morphine as a perioperative analgesic but has not been compared directly with sufentanil in clinical trials. The aims of this study were to compare the efficacy and safety of nalbuphine with that of sufentanil in patients undergoing colonoscopy and to determine the optimal doses of nalbuphine in this indication.

METHODS

Two hundred and forty consecutive eligible patients aged 18-65 years with an American Society of Anesthesiologists classification of I-II and scheduled for colonoscopy were randomly allocated to receive sufentanil 0.1 μg/kg (group S), nalbuphine 0.1 mg/kg (group N1), nalbuphine 0.15 mg/kg (group N2), or nalbuphine 0.2 mg/kg (group N3). Baseline vital signs were recorded before the procedure. The four groups were monitored for propofol sedation using the bispectral index, and pain relief was assessed using the Visual Analog Scale and the modified Behavioral Pain Scale for non-intubated patients. The incidences of respiratory depression during endoscopy, nausea, vomiting, drowsiness, and abdominal distention were recorded in the post anesthesia care unit and in the first and second 24-hour periods after colonoscopy.

RESULTS

There was no significant difference in analgesia between the sufentanil group and the nalbuphine groups (p>0.05). Respiratory depression was significantly more common in group S than in groups N1 and N2 (p<0.05). The incidence of nausea was significantly higher in the nalbuphine groups than in the sufentanil group in the first 24 hours after colonoscopy (p<0.05).

CONCLUSIONS

Nalbuphine can be considered as a reasonable alternative to sufentanil in patients undergoing colonoscopy. Doses in the range of 0.1-0.2 mg/kg are recommended. The decreased risks of respiratory depression and apnea make nalbuphine suitable for patients with respiratory problems.

Capnography in the Emergency Department: A Review of Uses, Waveforms, and Limitations

BACKGROUND

Capnography has many uses in the emergency department (ED) and critical care setting, most commonly cardiac arrest and procedural sedation.

OBJECTIVE OF THE REVIEW

This review evaluates several indications concerning capnography beyond cardiac arrest and procedural sedation in the ED, as well as limitations and specific waveforms.

DISCUSSION

Capnography includes the noninvasive measurement of CO₂, providing information on ventilation, perfusion, and metabolism in intubated and spontaneously breathing patients. Since the 1990s, capnography has been utilized extensively for cardiac arrest and procedural sedation. Qualitative capnography includes a colorimetric device, changing color on the amount of CO₂ present. Quantitative capnography provides a numeric value (end-tidal CO₂), and capnography most commonly includes a waveform as a function of time. Conditions in which capnography is informative include cardiac arrest, procedural sedation, mechanically ventilated patients, and patients with metabolic acidemia. Patients with seizure, trauma, and respiratory conditions, such as pulmonary embolism and obstructive airway disease, can benefit from capnography, but further study is needed. Limitations include use of capnography in conditions with mixed pathophysiology, patients with low tidal volumes, and equipment malfunction. Capnography should be used in conjunction with clinical assessment.

CONCLUSIONS

Capnography demonstrates benefit in cardiac arrest, procedural sedation, mechanically ventilated patients, and patients with metabolic acidemia. Further study is required in patients with seizure, trauma, and respiratory conditions. It should only be used in conjunction with other patient factors and clinical assessment.

Mainstream capnography system for nonintubated children in the postanesthesia care unit: Performance with changing flow rates, and a comparison to side stream capnography

INTRODUCTION

Monitoring of exhaled carbon dioxide (CO₂ ) in nonintubated patients is challenging. We compared the precision of a mainstream mask capnography to side stream sampling nasal cannula capnography. In addition, we compared the effect of gas flow rates on the measured exhaled CO₂ between mainstream mask and side stream nasal cannula capnography.

METHODS

A mainstream mask capnography system (cap-ONE) was tested. Children (weight of 7-40 kg, ASA 1-2) following anesthesia for minor procedures were assigned randomly to side stream or mainstream sampling groups. The side stream group wore a nasal cannula with CO₂ side port (NC). In the postanesthesia care unit, O₂ flow was started at 5 l·min^-1 , reduced to 2 and then 0.25 l·min^-1 every 3 min. Capnogram analysis measuring heights of all the waveforms was performed for continuous 120 s from the end of recording at each O₂ flow rate for each group.

RESULTS

Fifty-eight children were enrolled and 39 were analyzed (18 side stream NC and 21 mainstream mask). There were two mouth breathing children excluded from study in side stream NC group due to failure to capture measurable CO₂ waveforms. Peak CO₂ values measured by mainstream mask system were normally (Gaussian) distributed with smaller standard deviation (sd) at each O₂ flow than were those measured by side stream NC system which demonstrated irregular distributions with larger sd. Peak CO₂ values measurement was less affected by a change in flow rate in mainstream mask group than in side stream NC group (P = 0.04 in 5-0.25 l·min^-1 O₂ flow change).

CONCLUSION

A new mainstream mask system (cap-ONE) performed with greater precision than side stream NC monitoring regardless of mouth breathing. Measurement of peak CO₂ values by mainstream mask system showed normal distribution with smaller standard deviation (sd) and was less affected by O₂ flow change in predictable fashion.

Unrecognized hypoxia and respiratory depression in emergency department patients sedated for psychomotor agitation: pilot study

INTRODUCTION

The incidence of respiratory depression in patients who are chemically sedated in the emergency department (ED) is not well understood. As the drugs used for chemical restraint are respiratory depressants, improving respiratory monitoring practice in the ED may be warranted. The objective of this study is to describe the incidence of respiratory depression in patients chemically sedated for violent behavior and psychomotor agitation in the ED.

METHODS

Adult patients who met eligibility criteria with psychomotor agitation and violent behavior who were chemically sedated were eligible. SpO2 and ETCO2 (end-tidal CO2) was recorded and saved every 5 seconds. Demographic data, history of drug or alcohol abuse, medical and psychiatric history, HR and BP every 5 minutes, any physician intervention for hypoxia or respiratory depression, or adverse events were also recorded. We defined respiratory depression as an ETCO2 of ≥50 mmHg, a change of 10% above or below baseline, or a loss of waveform for ≥15 seconds. Hypoxia was defined as a SpO2 of ≤93% for ≥15 seconds.

RESULTS

We enrolled 59 patients, and excluded 9 because of ≥35% data loss. Twenty-eight (28/50) patients developed respiratory depression at least once during their chemical restraint (56%, 95% CI 42-69%); the median number of events was 2 (range 1-6). Twenty-one (21/50) patients had at least one hypoxic event during their chemical restraint (42%, 95% CI 29-55%); the median number of events was 2 (range 1-5). Nineteen (19/21) (90%, 95% CI 71-97%) of the patients that developed hypoxia had a corresponding ETCO2 change. Fifteen (15/19) (79%, 95% CI 56-91%) patients who became hypoxic met criteria for respiratory depression before the onset of hypoxia. The sensitivity of ETCO2 to predict the onset of a hypoxic event was 90.48% (95% CI: 68-98%) and specificity 69% (95% CI: 49-84%). Five patients received respiratory interventions from the healthcare team to improve respiration [Airway repositioning: (2), Verbal stimulation: (3)]. Thirty-seven patients had a history of concurrent drug or alcohol abuse and 24 had a concurrent psychiatric history. None of these patients had a major adverse event.

CONCLUSION

About half of the patients in this study exhibited respiratory depression. Many of these patients went on to have a hypoxic event, and most of the incidences of hypoxia were preceded by respiratory depression. Few of these events were recognized by their treating physicians.

Shake, rattle, and roll: an update on pediatric seizures

Seizure is a common presenting complaint for patients in the pediatric emergency department (PED) setting. In some cases, protocols are in place on how to manage this group of patients, for example, a patient with a simple febrile seizure already back to baseline or a patient with known epilepsy already back to baseline. However, many scenarios present dilemmas for physicians in the PED, specifically patients with status epilepticus (SE). Unfortunately, there is not a national SE protocol, and hospital-specific guidelines may or may not exist. Current practices are constantly changing because new medications arise, and more information is gathered regarding existing medications and guidelines. Here we will review the basics about first-time afebrile seizures presenting to the PED and common treatments specific to seizure types. We will then review SE management basics and medical therapy, including both older and newer agents and their routes of administration for both the prehospital and the hospital setting.

Accuracy of end-tidal CO2 measurement through the nose and pharynx in nonintubated patients during digital subtraction cerebral angiography

OBJECTIVE

To determine the accuracy of end-tidal CO2 (PETCO2) obtained in the nose through the Smart CapnoLine and in the pharynx through the modified Filterline H Set with supplemental oxygen at 5 L/min in nonintubated patients undergoing digital subtraction cerebral angiography (DSA).

TYPE OF STUDY

Prospective, observational.

PATIENTS

Twenty patients with disturbance of consciousness because of brain disease, who will receive DSA.

METHODS

PETCO2 was measured in the nose through the Smart CapnoLine and in the pharynx using the modified Filterline H Set that was inserted through the nasopharyngeal airway. Oxygen was administered through the Smart CapnoLine at a rate of 5 L/min. Five minutes after a constant and normally shaped capnography waveform, arterial blood was drawn from an indwelling femoral catheter for analyzing arterial CO2 partial pressure (PaCO2), and PETCO2 that was measured through the nose and the pharynx were simultaneously recorded. After the DSA procedure, PaCO2 was analyzed again. Data were analyzed with Pearson correlation and Bland-Altman analysis.

RESULTS

PETCO2 sampled from both the nose and the pharynx was significantly correlated with PaCO2, and the correlation coefficients had approximate values, 0.832 (P<0.0001) for PaCO2 with PETCO2 through the nose and 0.836 (P<0.0001) for PaCO2 with PETCO2 through the pharynx. The mean bias±SD for PETCO2 and PaCO2 was 4.53±2.76 mm Hg (nose) and 3.22±2.86 mm Hg (pharynx). The 95% level of agreement for PETCO2 and PaCO2 ranged from -0.90 to 9.95 mm Hg (nose) and from -2.39 to 8.82 mm Hg (pharynx). End-tidal CO2 measurements through the nose and the pharynx had comparable performance. The correlation of PETCO2 measured through the nose and the pharynx was 0.971 (P<0.001). The difference between PETCO2 measured through the nose and the pharynx was 1.31±1.25 mm Hg, and t test results showed that arterial to end-tidal CO2 pressure difference (Pa-ETCO2) in sampling through the nose was significantly greater than Pa-ETCO2 sampling through the pharynx (P<0.05).

CONCLUSIONS

In a clinical setting, end-tidal CO2 measurements sampled from the nose and the pharynx were accurate and reliable in nonintubated patients with a nasopharynx airway in place during DSA.

Capnography for the nonintubated patient in the emergency setting

BACKGROUND

Multiple studies illustrate the benefits of waveform capnography in the nonintubated patient. This type of monitoring is routinely used by anesthesia providers to recognize ventilation issues. Its role in the administration of deep sedation is well defined. Prehospital providers embrace the ease and benefit of monitoring capnography. Currently, few community-based emergency physicians utilize capnography with the nonintubated patient.

OBJECTIVE

This article will identify clinical areas where monitoring end-tidal carbon dioxide is beneficial to the emergency provider and patient.

DISCUSSION

Capnography provides real-time data to aid in the diagnosis and patient monitoring for patient states beyond procedural sedation and bronchospasm. Capnographic changes provide valuable information in such processes as diabetic ketoacidosis, seizures, pulmonary embolism, and malignant hyperthermia.

CONCLUSIONS

Capnography is a quick, low-cost method of enhancing patient safety with the potential to improve the clinician's diagnostic power.

Detection of hypoventilation by capnography and its association with hypoxia in children undergoing sedation with ketamine

OBJECTIVES

Hypopneic hypoventilation, a decrease in tidal volume without a change in respiratory rate, is not easily detected by standard monitoring practices during sedation but can be detected by capnography. Our goal was to determine the frequency of hypopneic hypoventilation and its association with hypoxia in children undergoing sedation with ketamine.

METHODS

Children who received intravenous ketamine with or without midazolam for sedation in a pediatric emergency department were prospectively enrolled. Heart rate, respiratory rate, pulse oximetry, and end-tidal carbon dioxide (ET(CO2)) levels were recorded every 30 seconds.

RESULTS

Fifty-eight subjects were included in this study. Fifty percent of subjects had recorded ET(CO2) values less than 30 mm Hg without a rise in respiratory rate. Twenty-eight percent of subjects experienced a decrease in pulse oximetry less than 95%. Patients who experienced a persistent decrease in ET(CO2) at least 30 seconds in length were much more likely to have a persistent decrease in pulse oximetry than those with normal or transient decreases in ET(CO2) (relative risk, 6.6; 95% confidence interval, 1.4-30.5). Decreases in ET(CO2) occurred on an average of 3.7 minutes before decreases in pulse oximetry.

CONCLUSIONS

Hypopneic hypoventilation as detected by capnography is common in children undergoing sedation with ketamine with or without midazolam. Hypoxia is frequently preceded by low ET(CO2) levels. Further studies are needed to determine if the addition of routine monitoring with capnography can reduce the frequency of hypoxia in children undergoing sedation.

Noninvasive capnometry for end-tidal carbon dioxide monitoring via nasal cannula in nonintubated neonates

BACKGROUND

Arterial blood gas analysis is the gold standard for assessing the adequacy of ventilation. However, arterial blood sampling may be associated with serious complications in neonates. The aim of the study was to utilize the side-stream capnometry measurement of end-tidal carbon dioxide (PetCO₂) via nasal cannula circuits and to verify the reliability of PetCO₂ in reflecting the arterial blood carbon dioxide(PaCO₂) level in nonintubated neonates.

METHODS

A retrospective medical record review analysis was performed in nonintubated neonates admitted to the neonatal ward in a medical center. Simultaneous arterial PaCO₂ and PetCO₂ levels were evaluated. PaCO₂ and PetCO₂ levels were compared by paired t test and were correlated using Pearson's correlation. The PetCO₂ bias was defined as the difference between PaCO₂ and PetCO₂, and was assessed by Bland-Altman plot analysis.

RESULTS

A total of 34 neonates were recruited, and data of 54 pairs of PaCO₂ and PetCO₂ levels were available for comparison. The average (mean ± SD) gestational age was 32.5 ± 4.2 weeks, and the average birth weight was 1881 ± 1077 g. There was a good correlation between PetCO₂ and PaCO₂ levels among all paired samples (r = 0.809, p < 0.001). When the data were divided into those with respiratory disease (n = 34) and those without (n = 20), significant correlation between PetCO₂ and PaCO₂ levels were both noted in the former group (r = 0.823, p < 0.001) and the latter group (r = 0.770, p < 0.001). The overall average mean value of PetCO₂ was lower than that of PaCO₂ (39.4 ± 8.8 mmHg vs. 41.3 ± 9.2 mmHg, p = 0.014). The difference between PetCO₂ and PaCO₂ levels was significant only among those with respiratory disease (38.8 ± 9.8 mmHg vs. 41.2 ± 10.3 mmHg, p = 0.027), but not among those without (40.5 ± 7.0 mmHg vs. 41.6 ± 7.2 mmHg, p = 0.289).

CONCLUSIONS

End-tidal CO₂ measurement by side-stream capnometry through nasal cannula could provide an accurate and noninvasive estimate of PaCO₂ levels in nonintubated neonates.

Sleep and epilepsy in children and adolescents

Epilepsy and sleep disorders are considered by many to be common bedfellows. Several sleep phenomena may occur during nighttime taking a wide variety of forms and which can mimic seizures. Although most seizure sub-types have the potential to occur during sleep or wakefulness, sleep has a well-documented and strong association with specific epilepsy syndromes. Seizures in sleep also tend to occur during lighter stages of non-REM (NREM) sleep. The neurophysiologic process involved in the deepening of NREM sleep may also facilitate both seizures and IEDs. Epilepsy per se and/or seizures themselves promote sleep disruption and significantly affect the quality, quantity, and architecture of sleep. There are many causes of sleep disruption in patients with epilepsy, including inadequate sleep hygiene, coexisting sleep disorders, and circadian rhythm disturbances. Seizures themselves can disrupt sleep, even when they occur during wakefulness. Anti-epileptic drugs (AEDs) can also alter sleep in positive and negative ways, and these effects are independent of anticonvulsant actions. The end result of sleep disruption is excessive daytime sleepiness, worsening seizures, and poor quality of life. Screening for sleep disorders in the epilepsy population and appropriate intervention strategies will lead to overall improved quality of life and seizure control.

Capnography monitoring in nonintubated patients with respiratory distress

OBJECTIVE

The objective was to assess agreement between end-tidal carbon dioxide values measured by a handheld capnometer (Petco(2)) and values measured by a blood gas analyzer (Paco(2)) in nonintubated patients with respiratory distress in an out-of-hospital setting.

METHODS

This prospective study compared Petco(2) values obtained by an end-tidal capnometer (Microcap Plus; Oridion Capnography Inc, Needham, Mass) to Paco(2) values by the Bland and Altman statistical method.

RESULTS

A total of 50 patients were included. Continuous Petco(2) monitoring was easily performed in all 50 patients during ambulance transport, but blood gas analysis failed in 1 patient. Agreement between the 2 methods was poor with a bias (mean difference) between Petco(2) and Paco(2) measurements of 12 mm Hg and a precision (SD of the difference) of 8 mm Hg. The gradient between Petco(2) and Paco(2) was greater than 5 and 10 mm Hg in 41 and 25 patients, respectively.

CONCLUSIONS

Petco(2) measurements poorly reflected Paco(2) values in our population of nonintubated patients with respiratory distress of various origins.

Assessment of end-tidal carbon dioxide during pediatric and adult sedation for endoscopic procedures

BACKGROUND

Pulse oximetry has become the standard of care during endoscopic procedures, despite the fact that significant alveolar hypoventilation may be undetected.

OBJECTIVE

To study the value of end-tidal carbon dioxide (EtCO(2)) measurement during pediatric and adult endoscopic procedures with the patient under general anesthesia (GA) and conscious sedation (CS).

DESIGN AND SETTINGS

Oridion Microcap hand-held capnography by using Smart Bite Bloc with oxygen (O(2)) delivery were used for the procedures. Microstream nondispersive infrared (IR) spectroscopy is used to measure the concentration of molecules that absorb IR light in CO(2) exhaled by the subject. For each patient, we defined an "event" based on a combination of a >or=20% change (increase or decrease) in EtCO(2), with at least one of the following: O(2) saturation (SPO(2)) <or=90%, a >or=20% change of pulse rate or respiratory rate.

PATIENTS

We studied 57 patients, with an age range of 4 to 62 years. Nineteen patients (33.3%) had CS and 38 (66.6%) had GA.

RESULTS

Twenty patients had no events, 32 had 1 event, and 5 patients had 2 events. The highest observed frequency of an event was noted during upper endoscopy under GA (0.35), followed by upper endoscopy under CS (0.32). Fitted univariate logistic regression models indicated that higher variability in EtCO(2) is associated with a higher probability for an event (P < .0001) and that an increase in age is associated with a lower probability for an event (P < .0001). Significant differences in the frequencies of SPO(2) events were related to the type of procedure (P = .0002; highest estimated probability for upper endoscopy) and GA (P < .0001). Similar conclusions were obtained based on the fitted multivariate model.

CONCLUSIONS

EtCO(2) contributes significantly to the prediction of events during endoscopy. A lower mean of EtCO(2), higher variability of EtCO(2), younger age, GA, and upper endoscopy increase the probability of an event.

Continuous end-tidal carbon dioxide monitoring in pediatric intensive care units

PURPOSE

End-tidal carbon dioxide (ETCO(2)) monitoring has a variety of clinical applications in critically ill pediatric patients. This study was designed to explore the current availability and utilization patterns for continuous ETCO(2) monitoring in pediatric intensive care units.

METHODS

A Web-based survey was distributed to directors of all accredited pediatric critical care fellowship programs in the United States.

RESULTS

Sixty-six percent of directors completed this survey. One hundred percent of directors had access to ETCO(2) monitoring for intubated patients and 57% for nonintubated patients. Eighty-three percent of respondents used ETCO(2) monitoring "always" or "often" for endotracheal tube confirmation. Fifty percent of respondents used ETCO(2) monitoring "always" or "often" for cardiopulmonary resuscitation, 38% for moderate sedation, and 5% for acid-base disturbances. All respondents who used ETCO(2) monitoring felt that it was easy to use. The most common reason for not using ETCO(2) monitoring was lack of availability (75%).

CONCLUSIONS

End-tidal carbon dioxide monitoring is widely available and used for intubated patients. However, it could be applied more frequently in other clinical situations in pediatric intensive care units.

Quantitative end-tidal carbon dioxide in acute exacerbations of asthma

OBJECTIVE

To examine quantitative end-tidal carbon dioxide (ETCO(2)) in children with acute exacerbations of asthma. We hypothesize that quantitative ETCO(2) will be lower in children during an acute exacerbation of asthma and will correlate with the severity of the exacerbation. We also hypothesize that ETCO(2) can be successfully performed in all groups in the setting of a pediatric emergency department.

STUDY DESIGN

Patients with acute exacerbation of asthma (n = 86) and control subjects without respiratory or metabolic disturbances (n = 88) were prospectively enrolled in a pediatric emergency department. A physical examination, vital signs, and ETCO(2) measurements were performed on arrival and, in the patients with asthma, after each bronchodilator treatment.

RESULTS

ETCO(2) was measured successfully in 97% of enrolled children. After adjusting for respiratory rate, ETCO(2) was significantly lower in patients with acute exacerbation of asthma than in control subjects (P < .001). ETCO(2) measured after the first and after the final bronchodilator treatment were significantly associated with the number of bronchodilator treatments received and with hospital admission (P < or = .002).

CONCLUSIONS

ETCO(2) can be successfully measured in all children and is significantly lower in children with acute exacerbations of asthma compared with healthy control subjects. Quantitative ETCO(2) may be an objective, noninvasive, and effort-independent way to assess the severity of asthma.

Current utilization of continuous end-tidal carbon dioxide monitoring in pediatric emergency departments

OBJECTIVE

End-tidal carbon dioxide (ETCO2) monitoring has numerous clinical applications in the emergency setting. This study was designed to explore the current availability and utilization patterns for continuous ETCO2 monitoring in pediatric emergency departments.

METHODS

A Web-based survey was distributed to directors of all accredited pediatric emergency medicine fellowship programs in the United States and Canada.

RESULTS

Eighty-one percent of directors completed this survey. Eighty-eight percent had access to ETCO2 monitoring for intubated patients and 53% for nonintubated patients. Seventy-nine percent of respondents used ETCO2 monitoring "always" or "often" for endotracheal tube confirmation. Only 20% of respondents used ETCO2 monitoring "always" or "often" for moderate sedation, 16% for trauma, and 6% for acid-base disturbances. One hundred percent of respondents who used ETCO2 monitoring felt that it was easy to use. The most common reason for not using ETCO2 monitoring was lack of equipment (65%).

CONCLUSIONS

ETCO2 monitoring is widely available, yet underutilized, for spontaneously breathing patients in pediatric emergency departments.

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.

Modified nasal cannula for simultaneous oxygen delivery and end-tidal CO2 monitoring during spontaneous breathing

BACKGROUND AND OBJECTIVES

Supplemental oxygen is commonly given via nasal cannulae in spontaneously breathing patients. Our modified nasal cannula with a clamp between the nasal prongs can provide O2 via one nostril and CO2 can be sampled through the other one. We have studied whether this cannula can provide oxygenation similar to a standard cannula without affecting end-tidal CO2 monitoring.

METHODS

Eighty-six patients were studied during spinal anaesthesia and sedation. In 15 patients, arterial blood was sampled while O2 was delivered at flow rates of 0, 2 and 4 L min(-1), with or without clamping between the prongs of our modified nasal cannula. In the remaining 71 patients, arterial O2 was measured while using our modified nasal cannula with the clamp applied. End-tidal CO2 was recorded on a capnograph and the correlation between end-tidal and arterial values with our modified nasal cannula was investigated.

RESULTS

No end-tidal CO2 waveforms were found with oxygen flow greater than 2L min(-1) without clamping between the prongs. With clamping there was a significant correlation (r = 0.83) between arterial and end-tidal CO2. A Bland-Altman analysis revealed a bias of 0.49 kPa with precision of +/-0.76 kPa. Arterial oxygenation was not affected by our modified nasal prongs with clamp as compared to the standard cannula.

CONCLUSION

Our modified nasal cannula can provide continuous monitoring of end-tidal CO2 without affecting oxygen delivery in sedated, spontaneously breathing patients.

Concordance between capnography and arterial blood gas measurements of carbon dioxide in acute asthma

STUDY OBJECTIVE

We examine the concordance between end-tidal partial pressure of CO2 (PetCO2) measured by capnography and arterial partial pressure of carbon dioxide (PaCO2) obtained by arterial blood gas in acute asthmatic patients presenting to the emergency department.

METHODS

This was a prospective observational cohort study of acutely ill adult asthmatic patients undergoing an arterial blood gas measurement as part of their evaluation. PetCO2 was recorded during exhalation into a capnograph while arterial blood was pulsing in the arterial blood gas tubing. Concordance between PetCO2 and PaCO2 was displayed as a Bland-Altman matrix, using prespecified limits of agreement of +/-5 mm Hg difference between PetCO2 and PaCO2 in each patient.

RESULTS

The mean difference between the PetCO2 and PaCO2 levels was 1.0 mm Hg (95% confidence interval -0.1 to 2.0 mm Hg), with a median of 0 mm Hg. Of the 39 patients enrolled, 37 (95%) fell within the a priori limits of agreement.

CONCLUSION

In adult asthmatic patients with acute exacerbations, concordance between PetCO2 measured by capnography and PaCO2 measured by arterial blood gas was high. These findings must be validated before capnography replacement of arterial blood gas as an accurate means of assessing alveolar ventilation in acute asthma is recommended.

Capnography as a rapid assessment and triage tool for chemical terrorism

The assessment and triage of victims of chemical terrorism in the emergency department and the prehospital setting has become an important priority. This article proposes the use of capnography as a prehospital assessment and triage tool for monitoring victims of chemical terrorism and for critically ill patients. Capnography provides the ABCs in less than 15 seconds and identifies the common complications of chemical terrorism. Further, the reliability of capnography is not affected by motion artifact or low perfusion and it is accurate and reliable in actively seizing patients. Emergency departments and emergency medical services systems should consider adding capnography to their chemical terrorism education and training.

Current limitations of volumetric capnography in surfactant-depleted small lungs

OBJECTIVE

To investigate the suitability of volumetric capnography for assessing alveolar gas exchange in very small, surfactant-depleted lungs.

DESIGN

Prospective animal trial.

SETTINGS

Animal laboratory in a university setting.

SUBJECTS

Twenty-one ventilated newborn piglets (age <12 hrs; median weight, 890 g; range, 560-1435 g).

INTERVENTIONS

Bronchoalveolar lavage with instillation of 30 mL/kg normal saline. Ventilatory, circulatory, and lung mechanic variables were measured before and 0, 30, and 60 mins after bronchoalveolar lavage.

MEASUREMENTS AND MAIN RESULTS

The alveolar deadspace fraction calculated by the Bohr and the Bohr/Enghoff equations increased three-fold (p<.001) after bronchoalveolar lavage in capnograms with distinct alveolar plateau, whereas in capnograms without alveolar plateau no statistical significant difference was seen. The main problem of capnography in small and especially stiff lungs was the high number of discarded records exclusively caused by a missing alveolar plateau. Rates of discarded records of capnography were 9.5% before lavage and increased (p<.01) to 52.4%, 47.6%,42.8% after bronchoalveolar lavage (0, 30, and 60 mins). With decreasing exhalation time, the number of discarded records increased significantly. No plateau was seen in >75% of recorded files with exhalation times <200 msecs. The effect of bronchoalveolar lavage on all variables measured was quite different, with the highest impact on required ventilatory settings, calculated oxygenation variables, and compliance. The effect of bronchoalveolar lavage on arterio-alveolar CO2 difference, CO2 production, and alveolar deadspace was much lower and statistically significant only in capnograms with alveolar plateau.

CONCLUSIONS

Volumetric capnography is a useful tool to detect impaired alveolar gas exchange in surfactant-depleted small lungs. However, the method failed if there was no alveolar plateau in the volumetric capnogram especially in stiff lungs with short exhalation times.

Capnometry for noninvasive continuous monitoring of metabolic status in pediatric diabetic ketoacidosis*

OBJECTIVE

To determine the utility of continuous noninvasive capnometry for monitoring pediatric patients with diabetic ketoacidosis as assessed by the agreement between end-tidal carbon dioxide (PetCO2) and PCO2

DESIGN

Clinical, prospective, observational study.

SETTING

University affiliated children's hospital.

INTERVENTIONS

Patients with diabetic ketoacidosis were monitored with an oral/nasal carbon dioxide (CO2) sampling cannula while in the emergency department. Laboratory studies were ordered per protocol. PetCO2 values were correlated with respiratory rate, PCO2, and pH.

MEASUREMENTS AND MAIN RESULTS

One hundred twenty-one patients were monitored for 5.9 +/- 0.32 hrs. The average (mean +/- sd) initial values for pH were 7.08 +/- 0.18; respiratory rate, 35.1 +/- 9.1 breaths/min; PetCO2, 18.6 +/- 10.8 torr; and venous PCO2, 20.2 +/- 10.6 torr. At the conclusion of the observation period, averages were pH, 7.29 +/- 0.05; respiratory rate, 22.4 +/- 3.7 breaths/min; PetCO2, 35.3 +/- 5.8 torr; and venous PCO2, 36.8 +/- 5.3 torr. For all 592 observations, the correlations between PetCO2 and venous PCO2 (r =.92, p =.0001), PetCO2 and pH (r =.88, p =.0001), Petco2 and respiratory rate (r = -.79, p =.0001), and respiratory rate and pH (r = -.80, p =.0001) were statistically significant and the correlations with respiratory rate were inversely related to pH and PetCO2. The difference scores were not related to the average scores for initial readings (r = -.073, p =.43), final readings (r = -.124, p =.18), and overall readings (r =.057, p =.17). Limits of agreement between the two methods were established with PetCO2 lower than venous PCO2 with 95% limits of agreement 0.8 +/- 8.3 (2 sd) torr.

CONCLUSIONS

PetCO2 monitoring of patients with diabetic ketoacidosis provides an accurate estimate of PCO2. Noninvasive PetCO2 sampling may be useful in patients with diabetic ketoacidosis to allow for continuous monitoring of patients.

End-tidal carbon dioxide monitoring stabilized hemodynamic changes during ECT

Accumulation of carbon dioxide (CO2) can disturb systemic and cerebral hemodynamics in patients receiving electroconvulsive therapy (ECT). The purpose of this study was to identify the effects of end-tidal CO2 monitoring on hemodynamic changes in patients who received ECT under propofol anesthesia. ECT was prescribed to 40 patients under propofol anesthesia. Ventilation was assisted using a face mask and 100% oxygen, with or without end-tidal CO2 monitoring. Heart rate was significantly increased in patients without end-tidal CO2 monitoring at 1 to 5 minutes after electrical stimulation (p < 0.01). Mean arterial blood pressure and middle cerebral artery blood flow velocity in the group without end-tidal CO2 monitoring were significantly larger than the values in the group with the monitor at 1 to 5 minutes after electrical stimulation. Arterial CO2 tension in the group without end-tidal CO2 monitoring was larger than the value in the group with the monitoring at 1 minute (45+/-5 mm Hg with the monitor and 56+/-8 without the monitor) and 5 minutes (37+/-4 mm Hg with the monitor and 51+/-8 without the monitor) after electrical stimulation (p < 0.01). Application of end-tidal CO2 monitoring is considered beneficial for safe and effective anesthesia management of patients undergoing ECT, especially patients with an intracranial disorder or ischemic heart disease.

Carbon dioxide kinetics and capnography during critical care

Greater understanding of the pathophysiology of carbon dioxide kinetics during steady and nonsteady state should improve, we believe, clinical care during intensive care treatment. Capnography and the measurement of end-tidal partial pressure of carbon dioxide (PETCO2) will gradually be augmented by relatively new measurement methodology, including the volume of carbon dioxide exhaled per breath (VCO2,br) and average alveolar expired PCO2. Future directions include the study of oxygen kinetics.

End-tidal carbon dioxide monitoring in emergency medicine, Part 2: Clinical applications

End-tidal carbon dioxide (PetCO2) monitoring is becoming more common in both the ED and the out-of-hospital setting. Its main use has been as an aid when confirming endotracheal intubation. Other uses in the ED include monitoring CPR efforts and monitoring the ventilatory and hemodynamic status of intubated and nonintubated patients. In addition, future uses may include using PetCO2 as an adjunct when monitoring the status of asthma treatment, when making the diagnosis of pulmonary embolism, and when measuring cardiac output noninvasively. This article reviews these specific uses of PetCO2 monitoring in emergency medicine.