Hypercapnia
Conditions
Keywords
hypercapnia, hyperpnoea, accelerated recovery
Brief summary
The proposed study will measure the time from the end of surgery until the time patients meet the discharge criteria from the postoperative anesthesia care unit and the time from the end of surgery until the patients regained cognitive function after anesthesia.
Detailed description
Hypercapnia has been used in conjunction with hyperpnoea to provide a more rapid return of responsiveness after inhaled anesthesia. In our first clinical study with isoflurane we confirmed that the time from turning off the vaporizer to opening of eyes was shortened by an average of 62% when the minute ventilation was elevated and the end tidal carbon dioxide concentration was kept at 52 mmHg rather than 28 mmHg during emergence. In our second study we found that hypercapnia and hyperpnoea accelerated recovery proportionately for sevoflurane and desflurane. The benefits of accelerating subject recovery in the operating room may extend to the entire recovery period if the subject is more alert and easier to care for when they arrive in the post anesthesia care unit.
Interventions
OTHERstandard of care for phase one anesthesia care
Patients received intravenous fentanyl at the discretion of the attending anesthesiologist. Anesthesia was induced with a remifentanil infusion, lidocaine, propofol, and rocuronium or succinylcholine at the anesthesiologist's discretion. Maintenance anesthesia was 6% end tidal desflurane with oxygen flows of 2 L/min (though clinicians could deviate from this at their discretion). Clinicians were directed to maintain blood pressure at ±20% of baseline. A baseline remifentanil infusion was used throughout each case, and both remifentanil and fentanyl were titrated at the anesthesiologist's discretion. Ventilation was adjusted to maintain an end tidal carbon dioxide concentration (EtCO2) of 35 mmHg. Ondansetron 4 mg was given prophylactically before the end of surgery.
DEVICEQuick Emergence Device
The Quick Emergence Device is placed between the endotracheal tube and the anesthesia breathing circuit to enable hypercapnia when ventilation is increased. The end-tidal gas sampling line is connected between the device and the endotracheal tube connector. Minute ventilation is doubled and the EtCO2 is elevated to approximately 48 mmHg from the previous maintenance level of 35 mmHg.
Sponsors
Anecare
University of Utah
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
HEALTH_SERVICES_RESEARCH
Masking
SINGLE (Caregiver)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* adults * ASA class I-III * both genders * scheduled to undergo eye surgery at the Moran Hospital.
Exclusion criteria
* a history of renal or hepatic disease, * chronic alcohol or drug abuse, * disabling neuropsychiatric disorder, * hypersensitivity or unusual response to other halogenated anesthetics, * pulmonary hypertension, * increased intracranial pressure, * seizure disorder * personal/familial history of malignant hyperthermia. * currently being treated with known hepatic enzyme-inducing drugs (e.g., phenobarbital, dilantin or isoniazid) * or with drugs known to alter anesthetic requirements (e.g., opiates, clonidine, alpha2 agonists, alcohol, anticonvulsants, antidepressants, barbiturates, benzodiazepines or other tranquilizers). * intolerance to non-steroidal anti-inflammatories. * have received general anesthesia within the previous 7 days, * received any investigational drug within the previous 28 days, * participated in a previous isoflurane or desflurane study * Female subjects can be neither pregnant nor breast feeding.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Recovery From Anesthesia | up to 2 hours | average time in minutes from the time the surgeon finished closing the surgical incision until the time the investigator in the postoperative care unit determined that the patients meet the discharge criteria from the postoperative anesthesia care unit (their vital signs had been stable for at least 30 min, their pain scores were less than the tolerable pain scores, they could sit up without dizziness or nausea, and their Aldrete score was ≥8). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Return of Cognitive Function | up to 30 minutes | average time in minutes from the time the surgeon finished closing the surgical incision at the end of surgery until the patients could correctly state their full name, the current year and their day, month and year of birth |
Countries
United States
Participant flow
Recruitment details
Subjects were recruited from March 28-August 25, 2008 through the surgery schedule at the Moran Eye Center
Participants by arm
| Arm | Count |
|---|---|
| Quick Emergence Device (QED) At the end of surgery, the Quick Emergence Device was placed between the endotracheal tube and the anesthesia breathing circuit. Minute ventilation was doubled and the end tidal carbon dioxide concentration (EtCO2) was elevated to approximately 48 mmHg. | 11 |
| Standard of Care At the end of surgery, the minute ventilation and EtCO2 remained at normal levels. The Quick Emergence Device was not used. | 11 |
| Total | 22 |
Baseline characteristics
| Characteristic | Quick Emergence Device (QED) | Standard of Care | Total |
|---|---|---|---|
| Age, Continuous Age | 43.7 years STANDARD_DEVIATION 15.1 | 40.4 years STANDARD_DEVIATION 15 | 42.1 years STANDARD_DEVIATION 15.1 |
| Region of Enrollment United States | 11 participants | 11 participants | 22 participants |
| Sex: Female, Male Female | 6 Participants | 6 Participants | 12 Participants |
| Sex: Female, Male Male | 5 Participants | 5 Participants | 10 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 0 / 11 | 0 / 11 |
| serious Total, serious adverse events | 0 / 11 | 0 / 11 |
Outcome results
Primary
Recovery From Anesthesia
average time in minutes from the time the surgeon finished closing the surgical incision until the time the investigator in the postoperative care unit determined that the patients meet the discharge criteria from the postoperative anesthesia care unit (their vital signs had been stable for at least 30 min, their pain scores were less than the tolerable pain scores, they could sit up without dizziness or nausea, and their Aldrete score was ≥8).
Time frame: up to 2 hours
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Quick Emergence Device (QED) | Recovery From Anesthesia | 53.0 minutes | Standard Deviation 15.2 |
| Standard of Care | Recovery From Anesthesia | 62.9 minutes | Standard Deviation 28.8 |
Comparison: We compared times for discharge criteria after general anesthesia with and without the QED.p-value: >0.05t-test, 2 sided
Secondary
Return of Cognitive Function
average time in minutes from the time the surgeon finished closing the surgical incision at the end of surgery until the patients could correctly state their full name, the current year and their day, month and year of birth
Time frame: up to 30 minutes
Population: number of participants determined by protocol
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Quick Emergence Device (QED) | Return of Cognitive Function | 10.9 minutes | Standard Deviation 5.1 |
| Standard of Care | Return of Cognitive Function | 18.2 minutes | Standard Deviation 9.7 |
Comparison: The effect of the use of hypercapnia and increased ventilation on the time to recovery events was compared using multivariate analysis of variance with the Hotelling's two sample T2.-test and the two-tailed unpaired t-test; individual comparisons were by Bonferroni adjusted two tailed unpaired t-tests. The data was tested for normality before identifying statistical significance.p-value: 0.039t-test, 2 sided