Arterial Blood Gas Partial Pressure Research Articles

Accuracy of a Novel Oxygen Mask Designed for Mainstream Capnometer in Non-intubated Pediatric Patients

Background: Capnography is useful for identifying postoperative apnea in non-intubated children. A Cap-ONE mask is a multi-functional face mask which can allow oxygen supply and simultaneous end-tidal CO2 (ETCO2) measurement in infant and pediatric as well as an adult patient. However, the accuracy of the ETCO2 measured via Cap-ONE has not been well evaluated especially in infant and pediatric patient. The aim of this study was to examine the correlation and level of agreement between ETCO2 obtained via Cap- ONE mask and arterial blood gas partial pressure of CO2 (PaCO2) in postoperative non-intubated pediatric patients in the intensive care unit (ICU). Methods: Postsurgical pediatric patients scheduled to admit to the ICU with invasive arterial pressure monitoring from April 2015 to March 2017 were enrolled. Patients with cardiac disease or facial abnormalities were excluded from the study. After arrival at the ICU, either small-sized (for 7-20 kg) or medium-sized (for 20-40 kg) Cap-ONE mask was installed on a patient face with oxygen supply at 5 L/min; then ETCO2 measurement was started. Once stabilized, the sample of arterial blood gas was analyzed to measure PaCO2. The relationship between ETCO2 and PaCO2 was examined by simple regression analysis. A Bland Altman plot was used to evaluate agreement between these two measurements. Results: A total of 77 ETCO2-PaCO2 paired values were obtained from 29 patients. In 23 (79.3%) patients, dexmedetomidine was administrated for sedation. The mean ± SD for ETCO2 and PaCO2 was 39.0 ± 8.5 mmHg and 41.5 ± 6.5 mmHg respectively (small group; 35.2 ± 8.7 mmHg and 37.8 ± 5.3 mmHg, medium group; 41.8 ± 7.3 mmHg and 44.2 ± 5.8 mmHg). Correlation coefficient (R2) was 0.554 (P<0.01) between ETCO2 and PaCO2 (small group; R2=0.431, medium group; R2=0.515). The mean bias ± SD between ETCO2 and PaCO2 was -2.38 ± 5.69 mmHg. The 95% level of agreement ranged from -13.54 to+8.78 mmHg (small group; -2.60 ± 6.55 mmHg, medium group; -2.40 ± 5.10 mmHg). Conclusion: ETCO2 obtained from Cap-ONE mask is correlated well with PaCO2 in postoperative non-intubated pediatric patients (aged 7 months to 14 years). The present study demonstrated that the Cap-ONE mask can provide a continuous, non-invasive, relatively reliable respiratory measurement in non-intubated, lightly sedated pediatric patients.

Cardiopulmonary effects of diazepam-ketamine-isoflurane or xylazine-ketamine-isoflurane during abdominal surgery in foals

To evaluate cardiopulmonary effects of anesthetic induction with diazepam and ketamine or xylazine and ketamine, with subsequent maintenance of anesthesia with isoflurane, in foals undergoing abdominal surgery. 17 pony foals. Foals underwent laparotomy at 7 to 15 days of age and laparoscopy 7 to 10 days later. Foals were randomly assigned to receive diazepam, ketamine, and isoflurane (D/K/Iso; n = 8) or xylazine, ketamine, and isoflurane (X/K/Iso; 9) for both procedures. During anesthesia for laparotomy, cardiac index, and mean arterial blood pressure ranged from 110 to 180 mL/kg/min and 57 to 81 mm Hg, respectively, in the D/K/Iso group and 98 to 171 mL/kg/min and 50 to 66 mm Hg, respectively, in the X/K/Iso group. Cardiac index, heart rate, and arterial blood pressures were significantly higher in the D/K/Iso group, compared with the X/K/Iso group. During anesthesia for laparoscopy, cardiac index and mean arterial blood pressure ranged from 85 to 165 mL/kg/min and 67 to 83 mm Hg, respectively, in the D/K/Iso group, and 98 to 171 mL/kg/min and 48 to 67 mm Hg, respectively, in the X/K/Iso group. Heart rates and arterial blood pressures were significantly higher in the D/K/Iso group, compared with the X/K/Iso group. There were no significant differences between groups during either experimental period for percentage end-tidal isoflurane, arterial blood gas partial pressures, or pH values. Anesthesia of foals for abdominal surgery with D/K/Iso was associated with less hemodynamic depression than with X/K/Iso.

High Donor Age, Low Donor Oxygenation, and High Recipient Inotrope Requirements Predict Early Graft Dysfunction in Lung Transplant Recipients

Early dysfunction in lung transplants is characterized by poor oxygenation, which may then lead to prolonged mechanical ventilation. This may be due to a combination of donor, recipient, and management factors. Our aim was to determine the incidence and severity of hypoxia and graft dysfunction and which factors were directly associated with poor oxygenation within the first 24 hours after lung transplantation. A retrospective study of all 128 lung transplants between 1999 and 2002 was undertaken. Multiple linear regression analysis was performed to determine which donor, recipient, operative, and intensive care unit (ICU) parameters were associated with the worst recorded arterial blood gas partial pressure of oxygen (PAO2)/fraction of inspired oxygen (FIO2) ratio in the initial 24 hours after operation. Eighty-three percent of the patients (104 of 128) had a PAO2/FIO2 ratio below 300 within the first 24 hours post-transplantation, and 60% (77 of 128) had a PAO2/FIO2 ratio below 200. A high donor age (p = 0.004), low donor PAO2 (p = 0.007), and high post-operative inotrope requirements (p = 0.02) were correlated with a low PAO2/FIO2 ratio. Recipient diagnosis, ischemic time, use of cardiopulmonary bypass, fluid balance in the ICU, and cardiac index were not related. There was no difference in the long-term outcomes of patients with high or low PAO2/FIO2 ratios. A low PAO2/FIO2 ratio is a common finding in the first 24 hours after lung transplantation. Donor factors such as age and PAO2, and the need for increasing inotrope requirements in ICU predict early graft dysfunction and hypoxia.

The use of quantitative end-tidal capnometry to avoid inadvertent severe hyperventilation in patients with head injury after paramedic rapid sequence intubation.

This study aimed to determine whether field end-tidal carbon dioxide CO2 (ETCO2) monitoring decreases inadvertent severe hyperventilation after paramedic rapid sequence intubation. Data were collected prospectively as part of the San Diego Paramedic Rapid Sequence Intubation Trial, which enrolled adults with severe head injuries (Glasgow Coma Score, 3-8) that could not be intubated without neuromuscular blockade. After preoxygenation, the patients underwent rapid sequence intubation using midazolam and succinylcholine. A maximum of three intubation attempts were allowed before Combitube insertion was mandated. Tube confirmation was accomplished by physical examination, qualitative capnometry, pulse oximetry, and syringe aspiration. Standard ventilation parameters (tidal volume, 800 mL; 12 breaths/minute) were taught. One agency used portable ETCO2 monitors, with ventilation modified to target ETCO2 values of 30 to 35 mm Hg. Trial patients transported by aeromedical crews also underwent ETCO2 monitoring. The primary outcome measure was the incidence of inadvertent severe hyperventilation, defined as arterial blood gas partial pressure of CO2 (pCO2) of less than 25 mm Hg at arrival, for patients with and those without ETCO2 monitoring. These groups also were compared in terms of age, gender, clinical presentation, Abbreviated Injury Score, Injury Severity Score, arrival arterial blood gas data, and survival. The study enrolled 426 patients and administered neuromuscular blocking agents to 418 patients. Endotracheal intubation was successful for 355 of these patients (85.2%). Another 58 patients (13.6%) underwent Combitube insertion. For 291 successfully intubated patients, arrival pCO2 values were documented, with continuous ETCO2 monitoring performed for 144 of these patients (49.4%). Patients with ETCO2 monitoring had a lower incidence of inadvertent severe hyperventilation than those without ETCO2 monitoring (5.6% vs. 13.4%; odds ratio, 2.64; 95% confidence interval, 1.12-6.20; p = 0.035). There were no significant differences in terms of age, gender, clinical presentation, Abbreviated Injury Score, Injury Severity Score, arrival partial pressure of oxygen (PO2) and pH, or survival. The patients in both groups with severe hyperventilation had a significantly higher mortality rate than the patients without hyperventilation (56 vs. 30%; odds ratio, 2.9; 95% confidence interval, 1.3-6.6; p = 0.016), which could not be explained solely on the basis of their injuries. The use of ETCO2 monitoring is associated with a decrease in inadvertent severe hyperventilation.

Sedative, analgesic, and cardiovascular effects of levomedetomidine alone and in combination with dexmedetomidine in dogs

To determine whether a high dose of levomedetomidine had any pharmacologic activity or would antagonize the sedative and analgesic effects of dexmedetomidine in dogs. 6 healthy Beagles. Each dog received the following treatments on separate days: a low dose of levomedetomidine (10 microg/kg), IV, as a bolus, followed by continuous infusion at a dose of 25 microg/kg/h; a high dose of levomedetomidine (80 microg/kg), IV, as a bolus, followed by continuous infusion at a dose of 200 microg/kg/h; and a dose of isotonic saline (0.9% NaCl) solution, IV, as a bolus, followed by continuous infusion (control). For all 3 treatments, the infusion was continued for 120 minutes. After 60 minutes, a single dose of dexmedetomidine (10 microg/kg) was administered IV. Sedation and analgesia were scored subjectively, and heart rate, blood pressure, respiratory rate, arterial blood gas partial pressures, and rectal temperatures were monitored. Administration of levomedetomidine did not cause any behavioral changes. However, administration of the higher dose of levomedetomidine enhanced the bradycardia and reduced the sedative and analgesic effects associated with administration of dexmedetomidine. Results suggest that administration of dexmedetomidine alone may have some cardiovascular benefits over administration of medetomidine, which contains both dexmedetomidine and levomedetomidine. Further studies are needed to confirm the clinical importance of the effects of levomedetomidine in dogs.

Anesthetic and cardiorespiratory effects of tiletamine-zolazepam-medetomidine in cheetahs

Objective— To evaluate anesthetic and cardiorespiratory effects of an intramuscular injection of a tiletamine-zolazepam-medetomidine combination in cheetahs. Design— Prospective study. Animals— 17 adult captive cheetahs. Procedure— The anesthetic combination was administered intramuscularly via a dart. Induction quality, duration of lateral recumbency, duration of recovery, and quality of anesthetic reversal with atipamezole were assessed. Cardiorespiratory variables (arterial blood gas partial pressures, arterial blood pressure, heart and respiratory rates, end-tidal CO2, oxygen saturation, and rectal temperature) were measured during anesthesia. Results— Sedation and lateral recumbency developed within 1.9 ± 1.0 (mean ± SD) and 4.3 ± 2.0 minutes of drug administration, respectively. Clinically acceptable cardiorespiratory and blood gas values were recorded for at least 87 minutes after drug administration in all but 1 cheetah. Hypoxemia and arrhythmias developed in 1 cheetah breathing room air but resolved after treatment with oxygen. Hypertension developed in all cheetahs. Significant differences in heart and respiratory rates, mean arterial blood pressure, arterial pH, partial pressure of oxygen, and hemoglobin saturation were found between cheetahs that did and did not receive oxygen supplementation. After administration of atipamezole, sternal recumbency and mobility returned within 6.9 ± 5.8 and 47.5 ± 102.2 minutes, respectively. Postreversal sedation, which lasted approximately 4 hours, developed in 4 cheetahs. Clinical Implications— Tiletamine-zolazepam-medetomidine delivered via a dart provided an alternative method for induction and maintenance of anesthesia in cheetahs. Atipamezole at the dose used was effective for reversal of this combination in the initial phase of anesthesia. (J Am Vet Med Assoc 1998:213:1022-1026)

Comparison of ketoprofen, oxymorphone hydrochloride, and butorphanol in the treatment of postoperative pain in dogs

Objective— To compare analgesic effects of ketoprofen, oxymorphone hydrochloride, and butorphanol when used to control postoperative pain associated with elective orthopedic surgery in dogs. Design— Prospective randomized clinical trial. Animals— 70 dogs undergoing orthopedic surgery on a hind limb. Procedure— Dogs were randomly assigned to 1 of 4 postoperative analgesic treatment groups: ketoprofen alone, oxymorphone alone, butorphanol alone, or ketoprofen-oxymorphone. Drugs were given IM at the end of anesthesia. Pain score, sedation score, arterial blood pressures, arterial blood gas partial pressures, and plasma Cortisol concentration were measured for 12 hours after surgery. If the pain score was ≥ 9, supplemental oxymorphone was administered IM. Results— The proportion of dogs that did not require supplemental treatment with oxymorphone was significantly higher for the ketoprofen alone and ketoprofen-oxymorphone groups than for the oxymorphone alone group. During the first hour after surgery, pain score was lower for oxymorphone alone and ketoprofen-oxymorphone groups than for ketoprofen or butorphanol alone groups. Significant differences were not detected among groups in regard to pain score 2 and 3 hours after surgery or in regard to arterial blood pressures at any time. From 4 to 12 hours after surgery, pain score was significantly lower for the ketoprofen alone group than for other groups. Plasma Cortisol concentration was significantly higher for the oxymorphone alone group 6 and 8 hours after surgery, compared with other groups. Clinical Implications— Except during the first hour after surgery, dogs given ketoprofen alone after elective orthopedic surgery had a greater level of, and longer-lasting, analgesia than did dogs given oxymorphone or butorphanol alone. (J Am Vet Med Assoc 1997;211:438–444)

Effectiveness of the peripheral chemoreflex control system in the adjustment of arterial O2 pressure and O2-Hb saturation.

From the view of control engineering, the respiratory chemoreflexes can be described as negative-feedback circuits (Cunningham, 1974; Loeschcke 1973a), whereby most empirical data refer to the sensitivity of the controller in terms of pulmonary ventilation as a function of arterial blood gas partial pressures. Although considered in theoretical models, there are only few experimental reports to describe the effectiveness of the controller, e.g. by Loeschcke, 1973b, for the central respiratory chemoreflex system in restoring the arterial PCO2 via brainstem extracellular fluid pH. Even less attention has been paid to the effectiveness of the peripheral chemoreflex during hypoxia.KeywordsCarotid BodyPulmonary VentilationModerate HypoxiaHypoxic Ventilatory ResponseCarotid Sinus NerveThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Effects of intramuscular or interpleural administration of morphine and interpleural administration of bupivacaine on pulmonary function in dogs that have undergone median sternotomy

Abstract Objective To evaluate effects of interpleural or IM administration of morphine and interpleural administration of bupivacaine on pulmonary function in dogs that have undergone median sternotomy. Design Experimental trial. Animals 18 healthy dogs. Procedure Dogs underwent median sternotomy and were randomly assigned to groups of 6 dogs each. Group-A dogs were given morphine (1.0 mg/kg of body weight) IM; group-B dogs were given 0.5% bupivacaine (1.5 mg/kg) interpleurally; and group-C dogs were given morphine (1.0 mg/kg) interpleurally. Heart rate; systolic, diastolic, and mean arterial pressures; rectal temperature; pain score; and arterial blood gas partial pressures were measured and pulmonary function testing was performed immediately after extubation (time 0) and up to 48 hours later. Serum cortisol and morphine concentrations were measured at time 0 and up to 12 hours after surgery. Results There was a significant decrease in pH, Pao2, mean oxygen saturation of hemoglobin, and dynamic compliance; and a significant increase in Paco2. alveolar-arterial difference in partial pressure of oxygen, pulmonary resistance, and work of breathing for dogs in all groups after surgery. Serum cortisol concentrations were significantly increased, compared with preoperative values, in all dogs. Serum cortisol concentrations were significantly higher in group-B dogs between 3 and 5 hours after surgery, compared with group-A dogs. Conclusions Median sternotomy was associated with significant alterations in pulmonary function. Effects of interpleural administration of bupivacaine and morphine were similar to effects of IM administration of morphine.(Am J Vet Res 1996;57:375-380)

Noncardiogenic pulmonary edema in dogs and cats: 26 cases (1987-1993)

Summary Medical records of 23 dogs and 3 cats treated for noncardiogenic pulmonary edema (npe) resulting from airway obstruction (n = 8), cranial trauma (7), electric shock (7), or seizures (4) between 1987 and 1993 were reviewed. There were 18 purebred dogs, 5 mixed-breed dogs, 2 domestic shorthair cats, and 1 Siamese. Sixteen animals were male, and 10 were female. All but 7 were less than 1 year old. Time between the inciting incident and onset of respiratory tract signs ranged from minutes to several hours. Respiratory distress was the primary clinical sign for all animals with npe resulting from airway obstruction, cranial trauma, or seizures, and for 2 of the 7 animals with npe resulting from electric shock. The only consistent clinicopathologic abnormality was hyperglycemia, which was detected in 12 animals. Arterial blood gas partial pressures were measured in 11 animals; 10 were hypoxemic. On thoracic radiographs, the predominant pattern of pulmonary infiltration was alveolar. Symmetry of involvement, which was assessed by examining dorsoventral or ventrodorsal radiographic projections, could be determined for 23 animals. In 18, involvement was asymmetric, and in 13 of those 18, the right side was predominantly involved. On lateral radiographic projections, the caudodorsal quadrant of the lung field was involved primarily or as part of a diffuse distribution in all but 1 animal. Generally, animals with npe resulting from airway obstruction had the greatest degree of radiographic involvement, followed in decreasing order, by animals with npe resulting from cranial trauma, animals with npe resulting from seizures, and animals with npe resulting from electric shock. Overall, 9 animals died. Four of the 8 animals with npe resulting from airway obstruction and 2 of the 7 animals with npe resulting from cranial trauma died or were euthanatized because of the severity of the pulmonary compromise. One animal with npe resulting from electric shock developed seizures and died. Two of the 4 animals with npe resulting from seizures were euthanatized because of the underlying cause of the seizures. Overall, 20 of the 26 animals were discharged, died, or were euthanatized within 48 hours of admission to the hospital.

Respiratory Changes in Horses during Automobile Transportation.

Transportation is generally recognized as a factor that raises the incidence of respiratory disorders in horses. However, their relationship to changes in respiratory function of horses during transportation have yet to be clarified in many respects. Furthermore, there is as yet no report concerning changes in arterial blood gas partial pressure and other parameters that reflect pulmonary ventilatory state in transported horses. In view of this, we conducted this study to clarify the relationship of transport with ventilatory function by investigating changes in respiratory pattern. Respiratory rate increased markedly as transport started (19.0±1.2/min.→42.4±8.2/min.), remained increased during the course of transport, and diminished close to a pre-transport level while at a stop. Arterial blood gases were not affected by respiratory rate, and did not reveal any significant change except a mild hyperventilatory state seen in febrile horses during transport.

Anaesthetic Agents and Their Effect on Tissue Protein Synthesis in the Rat

1. Rates of protein synthesis were measured, in vivo, in lung, liver, heart and skeletal muscle of young male rats. Groups of rats were exposed for 1 h duration to one of the following anaesthetic regimens: 1.4% halothane, 2.2% halothane, 1.4% halothane in 66% nitrous oxide, intravenous pentobarbitone (20 mg/kg) and intravenous midazolam (18 mg/kg) combined with fentanyl (2 micrograms/kg). Fractional rates of protein synthesis were determined by injecting [3H]phenylalanine (150 mumol/100 g body weight). 2. Liver protein synthesis was depressed significantly by all regimens, except midazolam/fentanyl, by up to 37.7% of control values. Lung protein synthesis was significantly reduced by all the anaesthetic agents by up to 30% of control rates. 3. The effects of the anaesthetic agents on skeletal muscle and heart were small and not statistically significant. 4. There was no evidence of ventilatory depression as manifested by changes in arterial blood gas partial pressures of CO2 and O2, except in the group treated with 2.2% halothane.

Complications of Cardiopulmonary Surgery

This book is designed for the general surgical resident and the thoracic surgeon in training. Its emphasis is on postoperative problems and topics of controversy. Its style is informal and makes no pretense at quantitating the frequency of the various complications or at being original. British terminology, such as in the naming of proprietary drugs or in referring to arterial blood gas partial pressure as kPa, is confusing to Americans. Some of the sections are out of date. For example, there is no mention of skinny needle aspiration biopsy of the lung or the percutaneous use of the intra-aortic balloon pump catheter. There are also certain glaring omissions, such as missing discussions of chronic postthoracotomy pain and aortic dissection as a complication of aortic cannulation or mention of surgical fixation of flail segments following blunt chest trauma. The best chapters are those that describe the initial evaluation and care of

Clinical Pathophysiological Study of Venous Blood Gas Partial Pressures and pH of Organs in Various Diseases

A number of studies have already been reported on the arterial blood gas partial pressures and pH. Also at the department to which the author belongs to, Saheki has made a study of clinical pathophysiological study of the arterial blood gas partial pressures and pH in various diseases. And although these studies have been available on the venous blood gas partial pressures and pH of coronary vein or of cerebrel vein only, yet no comparetive study has been made of the venous blood gas partial pressures and pH of other organs at the same time. Hence, in an attempt to comparatively examine the specific properties of gas metabolism of organs, the author determined the venous blood gas partial pressure and pH of brain, myocardium, liver, and kidneys.