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At least 379 records · Page 21Linked to original sources
PubMed1991

Prospective analysis of cardiopulmonary responses to laparoscopic cholecystectomy.

This prospective study evaluates the extent and temporal course of the cardiorespiratory effects of CO2 during laparoscopic cholecystectomy in otherwise healthy patients. Sixteen patients (M:F = 3:13, average age = 40.2 +/- 14.1 years) were monitored with capnography, transesophageal cardiac output, continuous blood pressure, heart rate, and pulse oximetry. Arterial blood gases were obtained immediately before insufflation of the abdomen with CO2 and before desufflation. Average operative time was 137 +/- 13 minutes. Patients were paralyzed and mechanically ventilated. Minute ventilation was increased if EtCO2 exceeded 45 mmHg or rose by more than 12 mmHg from baseline. End tidal (EtCO2) and arterial CO2 (PaCO2) increased from 31.4 +/- 0.7 mmHg to 42.1 +/- 1.6 mmHg and 33.3 +/- 0.7 mmHg to 43.7 +/- 1.2 mmHg, respectively, during the course of the procedure. Arterial pH decreased from 7.43 +/- 0.01 to 7.34 +/- 0.01, while bicarbonate concentration remained unchanged. Thirteen of the 16 patients required increased minute ventilation due to hypercarbia detected by capnography. Blood pressure increased from 78 +/- 2 mmHg (mean) at the start to 98 +/- 2 mmHg. This increase was coincidental with the maximal PaCO2. Good agreement was observed between paired EtCO2 and PaCO2 measurements. Laparoscopic cholecystectomy with carbon dioxide insufflation causes significant respiratory acidosis and associated cardiovascular changes in otherwise healthy patients. Careful monitoring and cautious application of this technique in patients with pre-existing cardiopulmonary disorders will be required to prevent acute decompensation.

Acidosis, Respiratory↗
PubMed2006

Patterns of hypocapnia on tilt in patients with fibromyalgia, chronic fatigue syndrome, nonspecific dizziness, and neurally mediated syncope.

OBJECTIVES: To assess whether head-up tilt-induced hyperventilation is seen more often in patients with chronic fatigue syndrome (CFS), fibromyalgia, dizziness, or neurally mediated syncope (NMS) as compared to healthy subjects or those with familial Mediterranean fever (FMF). PATIENTS AND METHODS: A total of 585 patients were assessed with a 10-minute supine, 30-minute head-up tilt test combined with capnography. Experimental groups included CFS (n = 90), non-CFS fatigue (n = 50), fibromyalgia (n = 70), nonspecific dizziness (n = 75), and NMS (n =160); control groups were FMF (n = 90) and healthy (n = 50). Hypocapnia, the objective measure of hyperventilation, was diagnosed when end-tidal pressure of CO2 (PETCO2) less than 30 mm Hg was recorded consecutively for 10 minutes or longer. When tilting was discontinued because of syncope, one PETCO2 measurement of 25 or less was accepted as hyperventilation. RESULTS: Hypocapnia was diagnosed on tilt test in 9% to 27% of patients with fibromyalgia, CFS, dizziness, and NMS versus 0% to 2% of control subjects. Three patterns of hypocapnia were recognized: supine hypocapnia (n = 14), sustained hypocapnia on tilt (n = 76), and mixed hypotensive-hypocapnic events (n = 80). Hypocapnia associated with postural tachycardia syndrome (POTS) occurred in 8 of 41 patients. CONCLUSIONS: Hyperventilation appears to be the major abnormal response to postural challenge in sustained hypocapnia but possibly merely an epiphenomenon in hypotensive-hypocapnic events. Our study does not support an essential role for hypocapnia in NMS or in postural symptoms associated with POTS. Because unrecognized hypocapnia is common in CFS, fibromyalgia, and nonspecific dizziness, capnography should be a part of the evaluation of patients with such conditions.

Adult↗
PubMed2006

Paramedic intubation of patients with severe head injury: a review of current Australian practice and recommendations for change.

Secondary brain injury may occur early after severe traumatic brain injury due to hypoxia and/or hypotension. Prehospital care by ambulance paramedics has the goal of preventing and treating these complications and, thus, improving outcomes. In Australia, most ambulance services recommend paramedics attempt endotracheal intubation in patients with severe head injury. Even though most patients with severe head injury retain airway reflexes, most states do not allow the use of appropriate drugs to facilitate intubation. In contrast, recent evidence from trauma registries suggests that this approach may be associated with significantly worse outcomes compared with no intubation. Two states allow intubation facilitated by sedative (but not relaxant) drugs, but this has a low success rate and could worsen brain injury because of a decrease in cerebral perfusion pressure. For road-based paramedics, the role of rapid sequence intubation is uncertain. Given the risks of this procedure and the lack of proven benefit, this procedure should not be introduced without supportive evidence from randomised, controlled trials. In contrast, for safety reasons, comatose patients transported by helicopter should undergo rapid sequence intubation prior to flight. However, this is not authorised in most states, despite good supportive evidence that this can be safely and effectively undertaken by paramedics. Finally, there is evidence that inadvertent hyperventilation is associated with adverse outcome, yet only two ambulance services use waveform capnography in head injury patients who are intubated. Overall, current paramedic airway practice in most states of Australia is not supported by the evidence and is probably associated with worse patient outcomes after severe head injury. For road-based paramedics, rapid transport to hospital without intubation should be regarded as the current standard of care. Rapid sequence intubation should be limited to use within appropriate clinical trials, or patients transported by helicopter. For patients who are intubated, waveform capnography is essential to confirm tracheal placement and to prevent inadvertent hyperventilation.

Adult↗
PubMed2005

Identification of endotracheal tube malpositions using computerized analysis of breath sounds via electronic stethoscopes.

Endotracheal tube (ETT) malpositioning into a mainstem bronchus or the esophagus may result in significant hypoxemia. Current methods to determine correct ETT position include auscultation, radiography, and bronchoscopy, although the current acceptable standard procedure for proper endotracheal (versus esophageal) intubation is detection of end-tidal carbon dioxide (ETco(2)) by capnography, capnometry, or colorimetric ETco(2) devices. Unfortunately, capnography may be unavailable or unreliable in nonhospital/emergency settings or in low cardiac output states, and it does not detect endobronchial intubation. The purpose of this study was to quantify and assess breath sound characteristics using electronic stethoscopes placed over each hemithorax and epigastrium to determine their ability to detect ETT malposition. We recorded breath sounds in 19 healthy, non-obese adults before general surgical procedures. After intubation of the trachea, the ETT was bronchoscopically positioned 3 cm above the carina, after which 3 breaths of 500 mL were given and breath sounds were recorded. A second ETT was placed in the esophagus and the same series of breaths and recordings were performed. Finally, the tracheal ETT was advanced into the right mainstem bronchus and breath sounds were recorded. Using computerized analysis, breath sounds were digitized and filtered to remove selected frequencies, and acoustic signals and energy ratios were obtained for all 3 positions. Total energy ratios using band-pass filtering of the acoustic signals accurately identified all esophageal and endobronchial intubation (P < 0.001). These preliminary results suggest that this technique, when incorporated into a 3-component, electronic stethoscope-type device, may be an accurate, portable mechanism to reliably detect ETT malposition in adults when ETco(2) may be unavailable or unreliable.

Blood Gas Analysis↗
PubMed2001

[Anesthesia for patients with unexpected pulmonary embolisms due to a large abdominal tumor obstructing with inferior vena cava].

Several reports have highlighted the risk of pulmonary embolisms during the preoperative period in patients with large abdominal tumors obstructing the inferior vena cava. We describe a patient who developed pulmonary embolism just before surgery. A 68[correction of 64]-year-old female was scheduled to undergo elective resection of a large abdominal tumor under general anesthesia. She had no signs of deep venous thrombosis, but on the day of the operation, pulmonary embolism developed suddenly. Anticoagulant therapy was performed. Capnography and pulmonary artery pressure were monitored during the perioperative period to detect the recurrence of pulmonary embolism. The percutaneous cardio-pulmonary support (PCPS) was also prepared. The operation was performed successfully. In this patient, the pulmonary embolism occurred suddenly during the preoperative period, even though we had ruled out the existence of deep venous thrombosis. This case report emphasizes the risk of pulmonary embolism in any patient with a large abdominal tumor obstructing the inferior vena cava. This case of a large abdominal tumor suggests that capnography, monitoring of pulmonary artery pressure and preparation of a PCPS in case of pulmonary embolism during surgery are necessary even in patients without signs of deep venous thrombosis.

Abdominal Neoplasms↗
PubMed1992

[Controlled hypotension? Watch the capnograph closely!].

During the surgery of the middle ear, a profound general anaesthesia associated to the monitoring of arterial hypotension may obtain a fiel of operation free of any blood. The patient surveillance needs the modern techniques of monitoring. SaO2 is altered only for severe falls of mean arterial pressure. PetCO2 reflects three factors: the cellular metabolism that is stable under general anaesthesia, the ventilatory conditions which are controlled and haemodynamic conditions. The cellular metabolism and the ventilatory being stable, PetCO2 modifications reflect mean arterial pressure variations. We have observed minimal falls of PetCO2 (2-3 mmHg) accompanying falls of mean arterial pressure. Monitoring mean arterial pressure every 5 minutes neglects periods of time. On the contrary capnography allows a constant haemodynamic survey. The capnography seems to be a precious help during the technique of controlled arterial hypotension.

Carbon Dioxide↗
PubMed1992

Efficacy of the FEF colorimetric end-tidal carbon dioxide detector in children.

Direct laryngoscopy and observation of endotracheal tube (ETT) passage between the vocal cords remain the criterion standard for verifying endotracheal intubation. Detection of end-tidal carbon dioxide (ETCO2) serves as an invaluable adjunct to confirm endotracheal intubation, detect inadvertent esophageal intubation, and monitor for accidental tracheal extubation. Capnography, however, is often unavailable outside the operating suite. A commercially available, disposable, colorimetric ETCO2 detector (FEF, Fenem, Inc., New York, N.Y.), in which color changes using a numerical scale semiquantitatively measure percent carbon dioxide in exhaled gases, has proved effective in confirming endotracheal intubation in adults, but has not been thoroughly investigated in children. We studied 20 otherwise healthy children, aged 6 mo to 8 yr, with simultaneous infrared and colorimetric ETCO2 measurements during elective general anesthesia to evaluate the efficacy of the colorimetric detector. Two hundred of 200 tracheally intubated positive-pressure breaths and 198 of 200 breaths under spontaneous mask ventilation demonstrated a yellow color change (color level 5 or 6), signifying an ETCO2 greater than or equal to 15 mm Hg (2.0 kPa). Repeated-measures analysis of variance revealed no significant differences in infrared ETCO2 values between the two yellow color levels throughout the study period. The associations among color level, infrared ETCO2 determinations, ETT size, and ETT "leak" pressures estimated by Spearman rank correlation analysis were significant only for higher infrared ETCO2 values with higher ETT leak pressures (P less than 0.05). No complications were observed. The Fenem disposable colorimetric ETCO2 detector effectively confirms clinical signs of endotracheal intubation in children when capnography is unavailable.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbon Dioxide↗
PubMedDate not supplied

A simple, disposable end-tidal carbon dioxide detector.

Detection of expired carbon dioxide is one of the most reliable methods of avoiding accidental esophageal intubation. Although capnography has become a standard monitoring technique in the hospital operating room, it is rarely available in the office setting or other arenas where emergency endotracheal intubation may be required. A new and inexpensive device, however, has been developed for assessing end-tidal carbon dioxide. This semi-quantitative detector fits between the endotracheal tube and the breathing circuit and uses a pH-sensitive indicator that changes color in response to different concentrations of carbon dioxide. Clinical studies indicate that this device provides similar results to standard capnography, and its inclusion in the emergency kit is strongly recommended.

Blood Gas Analysis↗
PubMed1989

[State of the ventilatory function of the lungs in heavy smokers].

Computed spirography, He/O test and capnography evaluation of external respiration has been carried out for 52 subjects. Of these 27 were nonsmokers, 25 smoked but had no history of respiratory diseases. The integral criteria of external respiration obstruction (MOCmax, MOC50, MOC75) proved inadequate diagnostic tool for early detection of ventilatory alterations in smokers who are at risk to develop chronic nonspecific pulmonary diseases. Pharmacological tests, He/O investigation and capnography did reveal defects in small bronchi permeability in all the smokers. Problems of pathogenesis of obstructive affections of distal regions of the bronchial tree are under consideration.

Humans↗
PubMed1989

[Invasive monitoring of arterial gases in intensive care. Indications, misuse and hazards].

Although arterial blood gas analysis remains the "gold standard" for oxygen (O2) and carbon dioxide (CO2) measurements during critical illness, several new techniques are now available for clinicians in this field, i.e. pulse oximetry, transcutaneous (PtcO2) and transconjunctival (PcjO2) O2 monitoring, CO2 continuous measurements in expired gases (capnography) and transcutaneous PCO2 (PtcCO2). While it seems too early to assign a definite role to all these techniques in the management of critically ill patients, several points can be emphasized: 1. pulse oximetry is a cheap, versatile device for monitoring of nonhypoxemic patients; 2. PtcO2 is a good index of poor skin oxygenation and is related to PaO2, but this index should be interpreted with caution in unsteady patients; perhaps its main value is as an early warning that "something is wrong with the patient". PcjO2 may be promising, but more data are needed; 3. PtcCO2 and capnography seem more suitable for research purposes or for patient monitoring in the operating theatre. Finally, it should be emphasized that invasive arterial blood gas measurements using an indwelliing arterial catheter are safe and provide with the best possible acid-base and hemodynamic monitoring. Noncontinuous monitoring of blood gases and, perhaps, the delay between arterial puncture and completion of the analysis seem to be the only drawbacks of this technique.

Blood Gas Analysis↗
PubMed1989

[Remote artificial respiration and anesthesia in nuclear magnetic resonance imaging].

Ferromagnetic equipment and equipment driven by alternate current cannot be used close to patients undergoing magnetic resonance imaging. Therefore, we tested a ventilator (Siemens Servo 900-D) that was placed more than 7 m away from the patient (outside the magnetic influence of 1.5 teslas) using tubing measuring 9 m in length. Tubing for children above the age of 8 and adults had a width of 22 mm; for neonates and children up to the age of 8 the width was 10 mm. Since the compressed air in such long tubes must be taken into consideration, we plotted nomograms for children and adults that helped to estimate respiratory minute volume including the compressed volume and a table to read the volume of compressed air that has to be added to respiratory volumes already established for ventilated patients from the ICU. In eight patients aged 7 weeks to 56 years (4 to 75 kg body wt.), capnography and blood gases showed that the nomograms were sufficiently accurate to allow safe ventilation. To improve safety, remote monitoring is recommended using long tubing or lines for oscillometric blood pressure measurement, capnography, and pulse oximetry as well as telemetric ECG.

Adult↗
PubMedDate not supplied

Respiratory monitoring for anesthesia and sedation.

This article reviews the theory and practice of routine respiratory monitoring during anesthesia and sedation. Oxygen monitoring and capnography methods are reviewed. The current ventilation monitoring system of choice is considered a combination of the pulse oximeter and capnography. Guidelines are provided for monitoring standards.

Anesthesia, General↗
PubMed1994

Determination of the onset of rebreathing in an enclosed afferent reservoir breathing system in anaesthetized, spontaneously breathing adults: a comparison of three methods.

We used three methods to determine the onset of rebreathing in the Ohmeda enclosed afferent reservoir breathing system and compared the results with the previously published rebreathing characteristics of this system. Of the methods studied, expiratory limb capnography proved unsuitable for determining the onset of rebreathing in this system. Inspiratory limb capnography and minimum inspired carbon dioxide at the mouth did enable the onset of rebreathing to be determined. However the fresh gas flow:minute volume ratio at which rebreathing occurred as determined by these criteria was less than that determined by the Kain and Nunn criteria and thus offer no clinical advantage over the latter.

Adult↗
PubMed1993

Carbon dioxide embolization and laparoscopic cholecystectomy.

The risk of venous air or CO2 embolization during laparoscopic biliary procedures is unknown. Sixty-one consecutive patients undergoing laparoscopic cholecystectomy at La Crosse Lutheran Hospital/Gundersen Clinic were monitored by precordial Doppler ultrasound and end-tidal capnography to determine the risk of gas embolization. Patients ranged in age from 19 to 77 years (mean, 47 years). No venous embolization was detected by Doppler ultrasound or capnography. The highest end-tidal CO2 ranged from 34 to 53 mm Hg (mean, 41 mm Hg). No patient demonstrated an abrupt change in end-tidal CO2. No significant intraoperative hemodynamic changes occurred, and no postoperative neurologic defects developed. We caution the surgical community to remain alert concerning the possibility of venous gas embolization as newer laparoscopic procedures are developed that may have increased risks of embolization.

Adult↗
PubMed1996

[Monitoring of multiple trauma in an emergency hospital unit].

In the monitoring of multiple trauma patients in the emergency hospital setting the use of monitors should be graduated. However, the use and interpretation of data from these monitors is becoming increasingly complex and can lead to errors and responses which may not be adopted. Clinical nomination and observation have their limits and the anaesthetist is faced with the added difficulties of interpretation of data from monitors and is pitfalls. The management of the patient is based on this human-machine relationship, which provides the basis for the therapeutic attitude and the treatment which ensues. Basic monitoring comprises a pulse oximeter, a capnograph, an ECG and a blood pressure monitor, 52% of incidents are detected by these instruments; 27% by SpO2, 24% by capnography. The pertinence is 82% for the oximeter when used alone and 55% for the capnography alone, although when the two are used together this increases to 88%. If the blood pressure monitor is added the pertinence increases to 93%, and to 95% if the FiO2 is monitored. The use of monitors of levels of haemoglobin or haematocrit must take into account the important variations in volaemia. The displayed values have a poor predictive value. The second level of monitoring comprises the use of a pulmonary artery catheter. The errors in measurement and interpretation are reviewed and finally, we consider the possible use of FOE transoesophageal echocardiography in the multiple trauma patient.

Blood Pressure Determination↗
PubMed2001

Case report: a normal capnogram despite esophageal intubation.

PURPOSE: To report a case of accidental esophageal intubation which could not be detected by capnography. CLINICAL FEATURES: A 43-yr-old man with osteogenic sarcoma of the mandible underwent mandibulectomy, radical neck dissection, reconstruction of the mandible and radiation therapy. He was scheduled for revision surgery to the mandible. He had a limited mouth opening and neck movement after operation and radiation. After the cuffed oropharyngeal airway (COPA) was inserted, anesthesia was induced with sevoflurane, and fibreoptic nasotracheal intubation attempted, but it was impossible to insert the fibrescope into the trachea because of a deformed larynx. While equipment for tracheostomy was prepared, one last attempt was made to insert the tube blindly into the trachea. The capnograph showed apparently normal carbon dioxide waveforms, and the reservoir bag inflated and deflated regularly. However, immediately after inflation of the cuff of the tracheal tube the reservoir bag movement stopped and CO(2) waveforms disappeared. Fibreoptic bronchoscopy showed that the tube was in fact in the esophagus. It was then noticed that the patient was still breathing spontaneously through the cuffed airway. The patient was awakened and tracheostomy performed. It was considered that egress of the expired gas was partially prevented by the cuffed airway, pooled in the oral cavity, aspirated down the esophagus during inspiration (likely to be due to negative intrathoracic pressure) and pushed out through the tube during expiration; inflation of the cuff prevented the gas entering the esophagus. CONCLUSION: Under such exceptional circumstances, apparently normal carbon dioxide waveforms were observed despite esophageal intubation in a spontaneously breathing patient.

Adult↗
PubMed2003

Both the OxyArm and Capnoxygen mask provide clinically useful capnographic monitoring capability in volunteers.

PURPOSE: To compare the capnography monitoring performance of the new OxyArm (OA) with the Capnoxygen mask (CM), a conventional oxygen mask with a carbon dioxide sampling port. METHODS: Eleven healthy volunteer adult subjects underwent capnographic monitoring (in a non-randomized, un-blinded crossover study) at baseline and while receiving oxygen at seven different flow rates (0.5, 1.0, 2.0, 4.0, 6.0, 8.0, and 10 L x min(-1)), applied first with the CM and then with the OA. RESULTS: Both the OA and CM produced acceptable capnographs with consistent waveforms. The measured end-tidal (ET) CO(2) was equivalent for the two devices at all seven oxygen flow rates. On average, the ETCO(2) measured with the OA was about 2 mmHg greater than that of the CM. Regression analysis showed an inverse relationship between oxygen therapy flow rate and measured ETCO(2) whereby the measured value of CO(2) decreased as the oxygen flow rate was increased (P < 0.001). Both the CM and OA produced consistent measurements of ETCO(2) as illustrated by their reliability coefficients, 0.95 and 0.86 respectively. The biggest source of variation in measured CO(2) for both devices was inter-subject differences, followed by variable oxygen flow rates. CONCLUSIONS: This study suggests that the OA and CM can prove useful for respiratory monitoring and oxygen delivery in spontaneously breathing volunteers, and the OA could potentially be used as an alternative to the conventional methods of oxygen delivery and CO(2) sampling in patients.

Adult↗
PubMed2000

[Remifentanil-propofol for bronchoscopic fiber optic intubation under capnographic control].

UNLABELLED: We report a case of a 41-years-old woman presenting for revision of a secondary reconstructive procedure using the modified Tagliacozzi upper arm flap after subtotal maxillectomy. Because of the pedicle flap the upper arm was fixed in a pre-facial position and so fiberoptic intubation was required. After routine pre-anesthetic preparations and topical anesthesia of the nares and nasopharynx a CO2 measuring catheter as well as a O2 catheter to administer 100% oxygen was inserted deeply into the left naris. At that time, a continuous infusion of 0.05 microgram/kg/min remifentanil and 2 mg/kg/h propofol was started. After 4 min, fiberoptic intubation was performed through the right nare without any technical difficulties in conscious sedation of the patient. During the entire fiberoptic intubation SaO2 was constant at 100% and capnogram tracings with etCO2 values ranging from 31 to 33 mmHg were displayed on the monitor. At the end of this second surgical procedure with fixed pre-facial upper arm position the patient was uneventfully extubated fully awake. For the time period of fiberoptic intubation the patient had complete amnesia. CONCLUSION: With the use of nasal capnography and capnometry in addition to simultaneous O2 administration during fiberoptic intubation under extreme conditions excellent analgosedation with propofol and remifentanil could be provided without compromising our patients' safety. The presented CO2 measuring and O2 administering device represents a simple and cheap expansion of standard anesthetic monitoring during fiberoptic intubation.

Adult↗