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At least 919 records · Page 51Linked to original sources
PubMed1998

Mainstream end-tidal carbon dioxide monitoring in the neonatal intensive care unit.

BACKGROUND: Continuous noninvasive monitoring of arterial carbon dioxide (CO2) in neonatal intensive care unit (NICU) patients would help clinicians avoid complications of hypocarbia and hypercarbia. End-tidal CO2 monitoring has not been used in this population to date, but recent technical advances and the introduction of surfactant therapy, which improves ventilation-perfusion matching, might improve the clinical utility of end-tidal monitoring. OBJECTIVE: To determine the accuracy and precision of end-tidal CO2 monitoring in NICU patients. DESIGN: Nonrandomized recording of simultaneous end-tidal and arterial CO2 pairs. SETTING: Two university NICUs. PATIENTS: Forty-five newborn infants receiving mechanical ventilation who had indwelling arterial access, and a predefined subsample of infants who were <1000 g birth weight, <8 days of age, and who received surfactant therapy (extremely low birth weight -ELBW- <8). OUTCOME MEASURES: The correlation coefficient, degree of bias, and 95% confidence interval were determined for both the overall population and the ELBW <8 subgroup. Those factors which significantly influenced the bias were identified. The ability of the end-tidal monitor to alert the clinician to instances of hypocarbia or hypercarbia was determined. RESULTS: There were 411 end-tidal/arterial pairs analyzed from 45 patients. The correlation coefficient was 0.833 and the bias was -6. 9 mm Hg (95% confidence interval, +/-11.5 mm Hg). The results did not differ markedly in the ELBW <8 infants. Measures of the degree of lung disease, the ventilation index and the oxygenation index, had small influences on the degree of bias. This type of capnometry identified 91% of the instances when the arterial CO2 pressure was between 34 and 54 mm Hg using an end-tidal range of 29 to 45 mm Hg. End-tidal values outside this range had a 63% accuracy in predicting hypocarbia or hypercarbia. CONCLUSION: End-tidal CO2 monitoring in NICU patients is as accurate as capillary or transcutaneous monitoring but less precise than the latter. It may be useful for trending or for screening patients for abnormal arterial CO2 values.

Capnography↗
PubMed2003

Comparison of propofol and sevoflurane for laryngeal mask airway insertion.

In this study, we compared haemodynamic changes, laryngeal mask airway (LMA) insertion time, and complications in patients anesthetized by inhalation of sevoflurane with those of intravenous induction with propofol. One hundred patients, aged between 20-40 years were enrolled in this study. Group 1 received propofol (2.5 mg/kg i.v.) and group 2 received sevoflurane (6%+50% N2O+50% O2) by inhalation using the tidal volume technique. LMA insertion time was found to be significantly longer in sevoflurane group than in propofol group. Mean arterial blood pressure was significantly lower within each group after induction in comparison to before induction values. In both groups, the LMA was successfully inserted in all patients. The quality of anaesthesia according to patients was significantly higher in the propofol group (80%) than in sevoflurane group (30%). Odor perception was significantly higher in sevoflurane group (84%) than in propofol group (38%). Apnoea was significantly higher in propofol group (40%) than in sevoflurane group (0%). Sevoflurane is an alternative to propofol for induction of anaesthesia and has a lower incidence of apnoea. Other complication rates are not higher than which propofol but the longer duration of induction time is a disadvantage.

Adult↗
PubMed2002

Comparison of a sidestream capnograph and a mainstream capnograph in mechanically ventilated dogs.

OBJECTIVE: To compare the ability of a sidestream capnograph and a mainstream capnograph to measure end-tidal CO2 (ETCO2) and provide accurate estimates of PaCO2 in mechanically ventilated dogs. DESIGN: Randomized, double Latin square. ANIMALS: 6 healthy adult dogs. PROCEDURE: Anesthesia was induced and neuromuscular blockade achieved by IV administration of pancuronium bromide. Mechanical ventilation was used to induce conditions of standard ventilation, hyperventilation, and hypoventilation. While tidal volume was held constant, changes in minute volume ventilation and PaCO2 were made by changing the respiratory rate. Arterial blood gas analysis was performed and ETCO2 measurements were obtained by use of either a mainstream or a sidestream capnographic analyzer. RESULTS: A linear regression model and bias analysis were used to compare PaCO2 and ETCO2 measurements; ETCO2 measurements obtained by both capnographs correlated well with PaCO2. Compared with PaCO2, mainstream ETCO2 values differed by 3.15 +/- 4.89 mm Hg (mean bias +/- SD), whereas the bias observed with the sidestream ETCO2 system was significantly higher (5.65 +/- 5.57 mm Hg). Regardless of the device used to measure ETCO2, bias increased as PaCO2 exceeded 60 mm Hg. CONCLUSIONS AND CLINICAL RELEVANCE: RelevancehAlthough the mainstream cas slightly more accurate, both methods of ETCO2 measurement correlated well with PaCO2 and reflected changes in the ventilatory status. However, ETCO2 values > 45 mm Hg may inaccurately reflect the severity of hypoventilation as PaCO2 may be underestimated during conditions of hypercapnia (PaCO2 > 60 mm Hg).

Animals↗
PubMed1999

[Portable capnographs in emergency care: a comparison of equipment].

Recently, transportable capnographs fulfilling the practical demands of emergency medicine have become commercially available (NPB-75, sidestream, Nellcor Puritan Bennett; and Tidal Wave, mainstream, Novametrix). A prerequisite for their use is an accuracy as required for clinical purposes (i.e., pCO2 +/- 2 mmHg). Additionally, environmental conditions in emergency medicine (e.g., changes in ambient temperature) should not have a significant impact on accuracy. The objective of this investigation was to analyse the accuracy of the two capnographs. The accuracy of the pCO2 measurement was evaluated under the following conditions: (1) measurement with three gas mixtures of defined concentrations (gas A: 5% CO2, 95% O2; gas B: 5% CO2, 20% O2, 75% N2; gas C: 10% CO2, 90% N2) related to STPD conditions (STPD = Standard Temperature and Pressure, Dry); and (2) exposure to changes in temperature (from +22 degrees C to -20 degrees C, and from -20 degrees C to +22 degrees C) applying the aforementioned 3 gas mixtures (STPD); and (3) in 20 patients manually ventilated with pure oxygen following endotracheal intubation (i.e., BTPS conditions = body temperature and pressure, saturated). Adequacy of the results was compared to the alveolar gas monitor AGM 1304 (Bruel & Kjaer, Copenhagen, Denmark; sidestream) which served as the reference method (providing an accuracy for the alveolar carbon dioxide partial pressure (pACO2) of +/- 1 mmHg). In the 3 dry gas mixtures, mean inaccuracy proved to be +4.5 +/- 4.1, +2.8 +/- 3.7, and +2.2 +/- 7.0 mmHg (gas A, gas B, gas C; STPD) with the Nellcor sidestream device. Using the Novametrix mainstream capnograph the results were found as follows: (1) -1.1 +/- 0.6, +2.9 +/- 0.6, and +5.6 +/- 2.3 mmHg (oxygen compensation enabled); and (2) +0.2 +/- 1.6, +2.2 +/- 0.6, and +3.2 +/- 4.2 mmHg (oxygen compensation disabled). After changing the environmental temperature (-20 degrees C / +22 degrees C), the resulting deviations (gases A-C, STPD) found with the Nellcor device averaged -12 +/- 4% and +15 +/- 3% (Nellcor); with the Novametrix mainstream device the deviations averaged -1 +/- 2% and +1 +/- 1%, and -2 +/- 1% and +1 +/- 1% (oxygen compensation enabled/disabled). Mean inaccuracy of the pCO2 measurement during ventilation of patients with pure oxygen (BTPS) was found to average -0.9 +/- 0.9 (Nellcor), and either +3.9 +/- 0.8 or +2.1 +/- 0.7 mmHg with the Novametrix (oxygen compensation enabled/disabled). Under BTPS conditions, both devices showed an acceptable deviation of the measurement accuracy up to a maximum of +/- 2 mmHg. The higher deviations of the "NPB-75" (Nellcor Puritan Bennett, sidestream) when using dry gas mixtures (STPD) may be explained by the automatic water vapour correction. Under the conditions of low and changing ambient temperature (-20 degrees C, +22 degrees C), only the "Tidal Wave" (Novametrix; mainstream) remained uninfluenced, whereas deviations of -12% and +15% were found with the "NPB-75".

Capnography↗
PubMed1999

Regional capnometry with air-automated tonometry detects circulatory failure earlier than conventional hemodynamics after cardiac surgery.

UNLABELLED: Gastrointestinal automated online air tonometry has been proposed for monitoring gastric perfusion in patients at risk of circulatory failure (CF) after cardiopulmonary bypass. In this study, CF was prospectively defined as the requirement for vasoactive support to maintain mean arterial pressure > or = 70 mm Hg after optimization of preload. Hemodynamic variables--oxygen (O2) delivery (DO2), O2 uptake (Vo2), venous-to-arterial [P(v-a)CO2], gastric-to-arterial [P(r-a)CO2], and gastric-to-end-tidal [P(r-et)CO2]Pco2 gap-were retrospectively compared in 14 patients with or without CF during a 12-hr postbypass period (HO-H12). In contrast to patients without CF (n = 7), in patients with CF (n = 7) increased VO2 was not associated with an increase in DO2. P(r-a)CO2 was larger at H0 in CF patients and was the only variable that differed between the two groups. P(v-a)CO2 did not vary significantly in both groups, whereas P(r-a)CO2 increased to a larger extent from H0 to H12 in patients with CF, suggesting selective gastrointestinal hypoperfusion in this group. P(r-et)CO2 provided comparable information to P(r-a)CO2. Hospital length of stay was 4 days longer (P < 0.05) in patients with CF. Increased P(r-a)CO2 and P(r-et)CO2, as monitored with automated air tonometry, were associated with rapid occurrence of CF and prolonged hospital stay after cardiac surgery. IMPLICATIONS: Regional and automated capnometry may be used noninvasively to identify patients at risk of circulatory failure after cardiopulmonary bypass earlier than with conventional variables.

Capnography↗
PubMed1999

Correlation of arterial and end-tidal carbon dioxide in spontaneously breathing patients during ambulatory gynecologic laparoscopy.

Laparoscopy can be performed while patients are under total intravenous anesthesia (TIVA), or sedated and breathing spontaneously through the normal airway. Respiratory monitoring is difficult when patients are sedated or anesthetized, however. The purposes of this study were to evaluate the reliability of end-tidal carbon dioxide (ETCO2) measurement for monitoring arterial carbon dioxide pressure (PaCO2), and to assess the PaCO2/ETCO2 gradient among patients receiving TIVA while breathing spontaneously through the normal airway. Sixty patients were divided into two groups: group 1 patients (n = 30) received general anesthesia with controlled ventilation, while group 2 patients (n = 30) received TIVA with spontaneous breathing through the normal airway; ETCO2 was sampled through a 10-French suction catheter inserted into the nasopharynx via the nasal airway. Arterial blood gas and ETCO2 were recorded at the time of preinduction, induction, CO2 insufflation, and change to Trendelenburg tilt position (20 degrees-30 degrees), and at 10-minute intervals thereafter. The results showed that ETCO2 was highly correlated with PaCO2 in group 1 (correlation coefficient r = 0.85), but not in group 2 (r = 0.55). In group 2, the PaCO2/ETCO2 gradient increased as time elapsed, with significant differences (p < 0.05) between the values at induction and those at 30 minutes after the change to the Trendelenburg position and thereafter. These results indicate that the ETCO2 and PaCO2 values correlate well during the first 20 minutes after the change to the Trendelenburg position in laparoscopy patients receiving TIVA with spontaneous breathing, but that PaCO2 monitoring is still necessary.

Adult↗
PubMed2001

End tidal carbon dioxide monitoring in spontaneously breathing, nonintubated patients. A clinical comparison between conventional sidestream and microstream capnometers.

BACKGROUND: To evaluate the end tidal carbon dioxide estimation in nonintubated, spontaneously breathing patients using either conventional sidestream or microstream capnometers. METHODS: Patients received a regional anesthesia technique, while the end tidal carbon dioxide partial pressure (EtCO2) was sampled through a nasal cannula (Nasal FilterLine, Nellcor, Plesanton, CA, USA) and measured using either a conventional sidestream capnometer with a 200 ml.min-1 aspiration flow rate, or a microstream capnometer (NBP-75, Nellcor Puritan Bennett, Plesanton, CA, USA) with an aspiration flow rate of 30 ml.min-1. After a 20 min period with stable hemodynamic variables (systolic arterial blood pressure within +/- 20% from baseline values), the EtCO2 was randomly recorded using one of the two capnometer while arterial blood was simultaneously drawn from the radial artery and analyzed for measurement of arterial CO2 partial pressure. Afterwards the nasal cannula was connected to the other capnometer and the procedure repeated. Both the capnometer and arterial blood gas analyzer were calibrated before each studied patient according to the manufacturer instructions. The same procedure was repeated at least two times in each patient. RESULTS: A total of 120 pairs of EtCO2 and PaCO2 measurements were drawn from 30 adults (age: 69 +/- 5 years; weight: 70 +/- 10 kg; height: 160 +/- 10 cm): 60 using the conventional sidestream capnometer and 60 with the microstream one. The median arterial to end tidal CO2 tension difference was 4.4 mmHg (range: 0.28 mmHg) with the microstream capnometer and 7 mm Hg (range: 0-22 mmHg) with the conventional capnometer (p = 0.02). CONCLUSION: The microstream capnometer provides a more accurate end tidal CO2 partial pressure measurement in nonintubated, spontaneously breathing patients than conventional sidestream capnometers, allowing for adequate monitoring of the respiratory function in nonintubated patients.

Aged↗
PubMed2001

Persistent hypercapnia in children after treatment of obstructive sleep apnea syndrome by adenotonsillectomy.

Obstructive sleep apnea syndrome (OSAS) in childhood is frequently in part a consequence of enlarged adenoids and/or tonsils and may lead to hypoxemia and hypercapnia during sleep. Whereas long-term blood gas alterations are well documented in adults, only few polygraphic data are available for children. It was the aim of this study to document blood gas alterations before and after treatment in this population. 9 children with OSAS (6 male, 3 female, median age 5.9 years, range 1.1-13.5 years) were investigated by polysomnography before and after adenotonsillectomy. Prior to intervention most children presented with moderate hypercapnia (ETCO2 mean 44.3 +/- 3.8 mm Hg, ETCO2 maximum 53.2 +/- 5.2) and hypoxemic episodes (oxygen saturation mean 93.2 +/- 3.2%, minimum 74.4 +/- 16.5%). Following adenotonsillectomy subsequent polygraphic investigations displayed normalisation of oxygen saturation (saturation mean 96.1 +/- 0.8%, minimum 90.1 +/- 3.1%). In contrast, moderate hypercapnia in several patients persisted up to five months after treatment (ETCO2 mean 44.9 +/- 2.8 mm Hg, ETCO2 maximum 51.2 +/- 3.6). Persistent hypercapnia most likely reflects an adaptation process of chemosensitivity and respiratory control due to preceding long-term hypercapnia.

Adaptation, Physiological↗
PubMedDate not supplied

Conscious sedation experiences in graduate pediatric dentistry programs.

PURPOSE: Conscious sedation is a behavior modification adjunct taught in all postgraduate pediatric dental residency programs. It has been a decade since the last survey was done specifically related to didactic and clinical aspects of conscious sedation in postgraduate pediatric dental programs. The aim of the study was to determine the clinical and didactic experiences associated with conscious sedation in these programs and to compare some of the findings to those collected a decade ago. METHODS: A 31-item survey similar to that of a decade ago was constructed and sent to all pediatric dentistry program directors of accredited postgraduate and residency programs in the United States. The items covered several didactics including didactic topics, sedative agents, monitoring, and emergency policy among others. A follow-up mailing was done involving those who had not responded 6 weeks following the initial mailing. RESULTS: Fifty-four of 58 (93%) program directors returned the 31-item survey. The following are highlighted findings. Conscious sedation among residency programs was achieved most commonly with a combination of sedative agents used with N2O. Midazolam was more popular than chloral hydrate. The oral route was the predominant route of administration. More lecture hours were spent on conscious sedation than 10 years ago. The pre-cordial stethoscope, pulse oximeter, and blood pressure cuff were the most commonly used monitors. Sedative agent and anticipated depth of sedation were the factors most often considered in choosing monitors used during the sedation of a patient. The capnograph was being used more frequently than it was 10 years ago. Programs did not report an increase in sedation emergencies but practiced emergency drills more often and had increased numbers of individuals certified in Advanced Cardiac Life Support (ACLS) or Pediatric Advanced Life Support (PALS). The percent of the total patient population which required sedation is about 1-20%, with most directors reporting an increase in the numbers of sedations done in the past few years. CONCLUSIONS: While many factors remained unchanged or slightly modified when compared to the survey done a decade ago, the results of this study suggest that there has been significant changes in several key factors including the most frequently used sedative (i.e., midazolam) and increased preparation in the area of emergency preparedness.

Administration, Oral↗
PubMed2001

End-tidal carbon dioxide measurements as a prognostic indicator of outcome in cardiac arrest.

PURPOSE: To evaluate the use of end-tidal carbon dioxide values in predicting survival in cardiopulmonary arrest. BACKGROUND: The decision about when to terminate resuscitative efforts for patients with cardiopulmonary arrest is often subjective. End-tidal carbon dioxide values have been suggested as potential objective criteriafor making this decision. METHODS: This study was a cooperative effort of the St Louis chapter of the American Association of Critical-Care Nurses and its members and involved 6 hospitals and an air evacuation service. All adult patients who had a cardiopulmonary arrest were eligiblefor the study. Once a patient with cardiac arrest was intubated, end-tidal carbon dioxide and cardiac rhythms were measured and recorded every 5 minutes for 20 minutes or until resuscitation efforts were terminated. Patients' survival at the time of the arrest, survival 24 hours after the arrest, and discharge status were followed up. RESULTS: A total of 127 patients were enrolled in the study. All but 1 patient with end-tidal carbon dioxide values less than 10 mm Hg died before discharge. End-tidal carbon dioxide values greater than 10 mm Hg were associated with various degrees of survival. Overall survival to discharge was less than 14%, regardless of the end-tidal carbon dioxide value. CONCLUSION: Measurements of end-tidal carbon dioxide can be used to accurately predict nonsurvival of patients with cardiopulmonary arrest. End-tidal carbon dioxide levels should be monitored during cardiopulmonary arrest and should be considered a useful prognostic value for determining the outcome of resuscitative efforts.

Capnography↗
PubMedDate not supplied

End-tidal carbon dioxide monitoring in pediatrics - clinical applications.

End-tidal CO2 monitoring is an exciting non-invasive technology that is more commonly used in the emergency department, intensive care unit and in the prehospital setting. Its main use has been in verifying endotracheal tube position, during mechanical ventilation and cardiopulmonary resuscitation, but it is being studied and used for other purposes as well. The new American Heart Association guidelines require secondary confirmation of proper tube placement in all patients by exhaled CO2 immediately after intubation and during transport. This article covers the clinical applications of end-tidal CO2 monitoring with special reference to the paediatric patient.

Capnography↗