Effects of coronary artery bypass related conduction defects: a 10-year follow-up study

OBJECTIVES

The aim of this study is to determine the long-term prognostic significance of new permanent conduction defects (CDs) related to coronary artery bypass grafting (CABG), and to assess predisposing factors for increased mortality after CABG.

DESIGN

One hundred and eighty patients who underwent an elective CABG without any evidence of preoperative CDs were followed on average for 9.6 years. Long-term outcome was observed in terms of Kaplan-Meier survival analysis, and several potential pre-, intra- and postoperative factors for increased mortality were analysed using the Cox regression model.

RESULTS

Sixty-three (35.0%) of the patients developed a new CD (CD+ group) before hospital discharge. Early (<30 days) and long-term (>30 days) survival rates were 98.9 and 86.1%, respectively. The long-term survival in CD+ patients was significantly lower that in CD- patients (77.8% vs 90.4%, p = 0.02). However, cardiac survival in CD+ patients and CD- patients did not differ from each other (88.9% and 92.3%, respectively, p=NS). Five independent predictors for increased all cause mortality were identified: diabetes (relative risk ratio 5.99 [2.43-14.78]), number of distal anastomoses (3.20 [1.30-7.88]), a new intraoperative conduction defect (2.83 [95% CI 1.24-6.49]), preoperative ejection fraction <50% (2.60 [1.08-6.27]) and perfusion time (1.02 [1.01-1.03]).

CONCLUSIONS

Excellent survival rates can be obtained 10 years after CABG. CDs were not related to increased cardiac mortality. The appearance of preoperative diabetes, intraoperative perfusion time, number of distal anastomoses performed, CABG derived permanent CDs and low preoperative ejection fraction are associated with higher all cause mortality during the long-term follow-up.

Elective Neck Dissection and Survival in Patients With Squamous Cell Carcinoma of the Oral Cavity and Oropharynx

OBJECTIVE/HYPOTHESIS

The utility of elective neck dissection in the management of patients with oral cavity and oropharyngeal cancer who present without neck metastases remains controversial. The study addressed the question of whether elective neck dissection improves regional control and survival in patients with squamous cell carcinoma of the oral cavity and oropharynx presenting with T1/T2 node-negative disease.

STUDY DESIGN

A nonrandomized, uncontrolled retrospective chart review.

METHODS

A nonrandomized, uncontrolled retrospective chart review was performed. Resection of the primary tumor was performed in all patients. The neck was observed in one group, and elective neck dissection was performed for patients in another group.

RESULTS

The study data indicated that elective neck dissection significantly improves regional control and regional recurrence-free survival. Elective neck dissection when compared with observation of the neck did not improve overall survival.

CONCLUSION

Elective neck dissection reduces regional recurrence and may extend disease-free survival.

AAA elective treatment indication tactics in EVAR era

The authors describe their indication tactics for AAA elective treatment. Based on one-month morbidity and mortality they evaluate the results obtained in the past six years and compare the methods of open surgery, endovascular repair and combined strategy in AAAs elective repair.

Free colorectal cancer cells on the peritoneal surface: correlation with pathologic variables and survival

BACKGROUND

Clinicopathologic staging of colorectal cancer remains the best predictor of survival. Prognostication for an individual with colorectal cancer remains elusive. This study was designed to investigate the incidence of free surface colorectal cancer cells detected by cytology during elective open curative resection, to correlate their presence with particular clinicopathologic variables and determine whether their presence was predictive of cancer-specific survival.

METHODS

Over a six-year period in one institution, all elective colon and intraperitoneal rectal cancer specimens were assessed during primary resection for the presence of free colorectal cancer cells by means of a simple and tested specimen imprint cytology methodology. Clinicopathologic variables were assessed prospectively and blinded to cytology results. All patients were followed up routinely until death and if the patient was not seen within the last six months, information was obtained from the New South Wales Registry of Births, Deaths and Marriages in Australia.

RESULTS

Overall, 26 of 281 (9.25 percent) colorectal cancers had positive cytology for cancer cells on the peritoneal surface of the bowel. Poorly differentiated tumors were significantly associated with positive cytology. Tumor penetration, presence of vascular or neural invasion, mucinous characteristics, lymph node status, and operative procedure performed were not statistically significant predictors of positive cytology. Overall, 43 of the 281 patients (15.3 percent) died during the mean follow-up period of 49.2 months from cancer-related deaths. Of these patients, 8 had positive cytology and 35 had negative cytology results. Cancer-specific survival assessed with the log-rank test was significantly associated with positive cytology in univariate (P = 0.008) and multivariate analysis (P < 0.001).

CONCLUSION

In this study, the presence of free surface colorectal cancer cells has been shown to be predictive of survival and is independent of direct peritoneal invasion and lymph node status. Thus, further assessment of this simple prognostic variable is warranted and selection of patients with positive cytology for possible adjuvant therapies may be beneficial.

Emergency Non-ruptured Abdominal Aortic Aneurysm

OBJECTIVES

To investigate symptoms and early mortality (<30 days) following open surgery for emergency, symptomatic non-ruptured abdominal aortic aneurysm (AAA).

DESIGN

Retrospective cohort study.

PATIENTS AND METHODS

During the period 1983-1994, 129 patients had an emergency admission, followed by surgery, for symptomatic non-ruptured AAA. Sixty-one received surgery within 24 h of admission and 68 received surgery more than 24 h after admission (median 135 h, inter-quartile range: 51-239 h). During the same period 239 patients had elective surgery for non-ruptured AAA. Early mortality (<30 days), symptoms and co-morbidities were recorded. Data were retrieved from the patient records.

RESULTS

Mortality (30 days) was 18% in the 61 patients having surgery within 24 h of emergency admission for non-ruptured AAA. Mortality following either delayed surgery (semi-elective) after emergency admission or elective surgery was 4.2% (p=0.0002). Four out of 11 patients who died within 30 days following an acute operation had previously been declared unfit for elective surgery. One additional emergency patient had been found unfit for open surgery, but survived a delayed operation.

CONCLUSION

The high mortality rate of patients with non-ruptured, symptomatic AAA undergoing surgery within 24 h of admission appears to be influenced by several factors, including co-morbidities and the acute operation. We propose that the 30-day mortality for non-ruptured AAA should be reported in two categories: mortality rate for elective surgery and mortality for surgery performed within 24 h of emergency admission. The term 'emergency non-ruptured' is a suitable term for the latter group.

Mechanical Bowel Preparation for Elective Colorectal Surgery

HYPOTHESIS

There is little scientific evidence to support the routine practice of mechanical bowel preparation (MBP) before elective colorectal surgery in order to minimize the risk of postoperative septic complications.

DATA SOURCES

Trials were retrieved using a MEDLINE search followed by a manual search of the bibliographic information in select articles. Languages were restricted to English, French, Spanish, Italian, and German. There was no date restriction.

STUDY SELECTION

Only prospective randomized clinical trials (RCTs) evaluating MBP vs no MBP before elective colorectal surgery were included.

DATA EXTRACTION

Outcomes evaluated were anastomotic leakage, intra-abdominal infection, wound infection, reoperation, and general and extra-abdominal morbidity and mortality rates. Data were extracted by 2 independent observers.

DATA SYNTHESIS

Seven RCTs were retrieved. The total number of patients in these RCTs was 1297 (642 who had received MBP and 655 who had not). Among all the RCTs reviewed, anastomotic leak was significantly more frequent in the MBP group, 5.6% (36/642), compared with the no-MBP group, 2.8% (18/655) (odds ratio, 1.84; P = .03). Intra-abdominal infection (3.7% for the MBP group vs 2.0% for the no-MBP group), wound infection (7.5% for the MBP group vs 5.5% for the no-MBP group), and reoperation (5.2% for the MBP group vs 2.2% for the no-MBP group) rates were nonstatistically significantly higher in the MBP group. General morbidity and mortality rates were slightly higher in the MBP group.

CONCLUSIONS

There is no evidence to support the use of MBP in patients undergoing elective colorectal surgery. Available data tend to suggest that MBP could be harmful with respect to the incidence of anastomotic leak and does not reduce the incidence of septic complications.

[Lessons learned from anesthetic management of pheochromocytoma resection: a report of three cases]

The anesthetic management of patients with pheochromocytoma, in which drastic hemodynamic changes may occur, is still a challenge to even the most experienced anesthesiologist, although the perioperative mortality has been reduced remarkably. We report three patients who developed unexpected major complications during elective resection of a pheochromocytoma. The Case 1 patient was a 46 year-old woman who developed ventricular tachycardia immediately after administration of ephedrine for transient hypotension induced by excessive phentolamine. Even a mild beta adrenergic agent may cause extraordinary stimulation to myocardium under alpha blockade. The Case 2 patient was a 44 year-old man who needed intensive vasodilating therapy due to an exaggerated cardiovascular response to intraoperative surgical stress. He developed severe metabolic acidosis resembling hyperdynamic shock before resection of the tumor, although blood pressure was controlled within the expected range. The Case 3 patient was a 60 year-old woman who did not receive preoperative alpha blocker therapy because she lacked cardiovascular symptoms. However, she revealed a high level of systemic vascular resistance after induction of general anesthesia and needed moderate inotropic support to compensate for an abrupt reduction of vascular resistance after resection of the tumor. The pathophysiology of the disease is complex and anesthetic care must be tailored in accordance with each patient's situation.

Unsuspected non-Hodgkin's lymphoma discovered with routine histopathology after elective total hip arthroplasty

The utility and cost-effectiveness of routine histologic examination of specimens from elective total joint procedures continues to be a source of debate. We describe a case of unsuspected non-Hodgkin's lymphoma discovered after routine histopathologic examination of a femoral head with osteoarthritis. The evidence both for and against routine tissue submission after elective arthroplasty cases is outlined in a review of the literature. By illustrating a neoplasm that would have been missed without routine pathologic examination, this case underscores a need for continued scrutiny of methods to effectively reduce medical costs while maintaining quality of care.

Effectiveness of bupropion as an aid to stopping smoking before elective surgery: a randomised controlled trial

Smoking is a risk factor for complications during and after surgery, but most smokers are unable to quit before elective surgery. We tested the efficacy of bupropion in improving smoking cessation rates in this setting by enrolling 47 patients from the elective surgery waiting list in a double-blind randomised controlled trial. Patients receiving bupropion had a lower daily cigarette consumption at the time of hospital admission, median (IQR) cigarettes per day: 6 (2-7) vs. 15 (9-20), p = 0.046. They also had a reduction in end-expired carbon monoxide (p = 0.004), a known contaminant of cigarette smoke, and increased arterial oxygen saturation on pulse oximetry (p = 0.011). They were more likely to have stopped smoking at the 3-week visit (p = 0.036), but not at the 6-week visit (p = 0.25) or at the time of hospital admission for surgery (p > 0.99). This study found that smokers waiting for elective surgery are more likely to reduce or stop smoking when treated with bupropion.

Early and late reversal of rocuronium with pyridostigmine during sevoflurane anaesthesia in children

This study investigated the effect of pyridostigmine administered at different levels of recovery of neuromuscular function after rocuronium during sevoflurane anaesthesia in children. Fifty-one patients aged 3 to 10 years, ASA physical status 1 or 2 were randomized to 4 groups: a spontaneous recovery group; or, reversal with pyridostigmine 0.25 mg/kg with glycopyrrolate 0.01 mg/kg at one of three times: 5 minutes after rocuronium administration; at 1% twitch height (T1) recovery; or at a 25% twitch height (T25) recovery. Anaesthesia was induced with thiopentone (5-7 mg/kg) and maintained with 2-3% sevoflurane and 50% nitrous oxide. Atropine (0.015 mg/kg) and, after calibrating the TOF-Watch, rocuronium (0.6 mg/kg) were then administered. Maximal block occurred 1.1+/-0.5 min (mean, SD) after rocuronium administration. In the spontaneous recovery group, the clinical duration (recovery to T25) was 40.1+/-8.8 min and the recovery index (time between T25 and T75) 19.9+/-9.8 min. Recovery to TOF >0.9 from the time of rocuronium administration was reduced by approximately 30% in the pyridostigmine groups compared to the spontaneous recovery group. There was no significant difference among the three pyridostigmine groups. When pyridostigmine was given at T1 or T25, the time from pyridostigmine administration to TOF >0.9 was shorter than for the group receiving pyridostigmine 5 minutes after rocuronium.

Multivariate predictors of occult neck metastasis in early oral tongue cancer

OBJECTIVES

The elective dissection of cervical lymph nodes from patients with early oral tongue cancer and a clinically negative neck (T1/T2N0), remains an unsettled issue that continues to be investigated. This study examines clinical and histopathologic factors through univariate and multivariate analysis to correlate the risk of neck micrometastasis in patients with T1/T2N0 squamous cell carcinoma of the oral tongue.

STUDY DESIGN AND METHODS

The clinical files and histologic sections of tumor from 45 clinically determined N0 patients were retrospectively analyzed. The factors examined include degree of tumor cell differentiation, T1/T2 staging, presence of perineural invasion, presence of angiolymphatic invasion, type of invasion front, depth of muscle invasion, and tumor thickness.

RESULTS

Independent correlates of positive occult neck metastasis included greater tumor thickness ( P = 0.01), greater depth of muscle invasion ( P = 0.01), T2 stage ( P = 0.01), poorly differentiated tumors ( P = 0.007), infiltrating-type invasion front ( P = 0.03), presence of perineural invasion ( P = 0.001), and presence of angiolymphatic invasion ( P = 0.005). The final multivariate model for estimation of an increased probability of occult neck disease included greater tumor thickness, presence of perineural invasion, infiltrating-type invasion front, poorly differentiated tumors, and T2 stage.

CONCLUSIONS

The clinical and histopathologic factors studied herein permit greater selectivity and more informed decision-making than does presurgical evaluation, when addressing elective neck treatment for early N0 oral tongue cancer. The multivariate model derived from this study appears to be a more reliable method for determining the patients most likely to benefit from elective neck dissection.

Four-year follow up of patients with untreated abdominal aortic aneurysms

BACKGROUND

The data in the literature are still controversial describing the outcome of patients not treated for a large abdominal aortic aneurysm (AAA) especially with significant comorbidities. We followed up patients trying to establish their long-term outcome.

METHOD

Since 1998, we have prospectively followed all patients referred to our department with AAA. A retrospective analysis was carried out selecting all patients who had an AAA larger than 5 cm, and who declined or were declined for operative repair between February 1998 and November 2001.

RESULTS

One hundred and eleven patients were included in the present study. There were 78 men and 33 women. The mean age was 80 years. At the end of the study, 65 patients (59%) were deceased. Ruptured aneurysm occurred in 27 patients (median time to rupture = 14 months) with one patient surviving an emergency repair. Thirty-nine patients died from unrelated illnesses. In the 5-5.9 cm AAA group (n = 58), out of 31 deceased patients, five (16%) have died of ruptured AAA. In the 6 cm and larger AAA group (n = 53), out of 34 deceased patients, 21 (62%) have died of ruptured AAA. There was no significant difference in survival between patients with AAA below and above 6 cm in diameter (P = 0.15).

CONCLUSION

In the presence of significant comorbidities, most patients with AAA less than 6 cm died from unrelated illnesses. In the larger AAA group, the likelihood of death from AAA rupture or unrelated illnesses is almost equal.

[Preoperative adverse events during stereotactic microelectrode-guided deep brain surgery in Parkinson's disease]

OBJECTIVES

To evaluate the prevalence of adverse events and complications during surgery using deep brain electrodes, mainly in the treatment of Parkinsonism. To describe the adjustment of propofol to meet the needs of neurophysiological monitoring.

PATIENTS AND METHODS

A prospective study of patients undergoing stereotactic microelectrode-guided deep brain surgery (stereotactic pallidotomy, implantation of electrodes in the thalamic or subthalamic neurons of the globus pallidus). After placement of a stereotactic frame and completion of a computed tomography scan of the head, the patients were transferred to the operating room. Monitoring included electrocardiography, pulse oximetry, arterial pressure (invasive), endtidal carbon dioxide pressure, and diuresis. Anesthesia was maintained by intermittent infusion of propofol. Variables recorded were age, sex, disease and time elapsed since diagnosis, surgical complications and their treatment, total dose of propofol, duration of surgery, and place of transfer for recovery.

RESULTS

One hundred twenty-eight patients (50 women, 78 men) with a mean (+/- SD) age of 59.6 +/- 10.2 years underwent the procedure from 1996 through 2003. The mean time elapsed since diagnosis of the disease was 14 +/- 6.2 years. The propofol dose was 890.6 +/- 571.4 mg and duration of surgery was 8.3 +/- 2.4 hours. Adverse events were observed for 101 patients (78.9%). The most common complications involved hemodynamics: arterial hypertension (59.4%), bradycardia (18.0%), arterial hypotension (7.9%), and tachycardia (6.2%). Other more serious complications were pneumocephalus with clinical repercussions (3 cases), globus pallidus hematoma (2), air embolism (2), epileptic seizure (3), anisocoria (1), and dyspnea and/or airway obstruction (7).

CONCLUSIONS

Deep brain stimulation requires surgery of long duration. Because of frequent episodes of arterial hypertension, which increases the risk of brain hemorrhage, and other less common but potentially dangerous complications, careful clinical monitoring is necessary during the procedure. The intermittent use of propofol does not interfere with neurophysiological monitoring.

A new pepsin assay to detect pulmonary aspiration of gastric contents among newly intubated patients

Aspiration of gastric contents by endotracheally intubated patients is associated with significant morbidity and mortality. Previous studies suggest that pepsin in tracheal aspirates may be a valuable marker of occult aspiration. We sought to show the sensitivity and specificity of a new, pepsin-specific assay in humans. A prospective, case-controlled study was conducted with subjects serving as their own controls. After planned endotracheal and nasogastric intubation for elective surgery, 20 participants had tracheal and gastric aspirates withdrawn. A blinded investigator tested samples for the presence of pepsin using the assay. Positive samples were then tested with pepstatin, a specific pepsin inhibitor, to ensure that positive results were due to pepsin. All tracheal aspirates tested negative and all gastric aspirates tested positive for pepsin. Pepstatin halted pepsin activity in all positive samples, ensuring that positive results were due to pepsin. A pepsin-specific assay is extremely reliable for detecting gastric contents in humans.

Cardiac surgery in octogenarians

BACKGROUND

Early and late results were studied in order to improve the indications for surgery in the elderly.

METHODS

Two hundred and thirty-seven patients aged 80 years or older underwent cardiac surgery between 1987 and 2001. The mean age of patients, which included 148 men and 89 women, was 82 years. Elective operations were performed in 194 patients and urgent or emergency operations in 43. Coronary artery bypass grafting (CABG) was performed in 104 patients, valve surgery in 60, CABG plus valve in 58, and other surgery in 15. Late results were obtained in 91% of patients, and the mean follow-up period was 54 months.

RESULTS

Operative mortality was 9% in total; 7% in CABG, 5% in valve, 10% in CABG plus valve. Operative mortality was significantly higher in the urgent/emergency group than in the elective group (25% vs 6%). The actuarial survival rate for hospital survivors at 60 months after surgery was 75% and the mean survival period 76 months. There were no significant differences among operations. Preoperatively 81% of the patients had been in New York Heart Association class III or IV, and 88% of survivors were in class I or II in the late period.

CONCLUSIONS

Early and late results for elective surgery in octogenarians are satisfactory. However, for urgent or emergent cases, there is a marked increase in morbidity and mortality.

Comparison of EORTC quality of life core questionnaire (EORTC-QLQ-C30) and gastrointestinal quality of life index (GIQLI) in patients undergoing elective colorectal cancer resection

BACKGROUND

EORTC-QLQ-C30 questionnaires and GIQLI questionnaires are used to evaluate post-operative quality of life (QoL). It was not clear whether results of both instruments are comparable. Therefore, the level of agreement between both QoL questionnaires was evaluated in patients undergoing elective colorectal cancer resection.

METHODS

Pre-operatively, 7 and 30 days after surgery 116 patients answered the EORTC-QLQ-C-30 and the GIQLI questionnaires in random order. Individual questions with similar content from each questionnaire were compared. Data for global QoL, physical (PF), emotional (EF) and social function (SF) were linearly transformed to fit a scale from 0 to 100. Data from the two instruments were correlated and the level of agreement between them was calculated according to the method of Bland and Altman.

RESULTS

A total of 308 data sets [(pre-op. n=116; 7th pod n=101; 30th post-operative day (pod) n=91)] were evaluated. Both instruments detected a reversible reduction of QoL after surgery and gave inferior results for patients with conditions known to impair QoL. EORTC-QLQ-C30 was more sensitive than GIQLI. The correlation between the two questionnaires for global QoL, PF and EF was good ( r=0.53-0.66, p<0.01), but no correlation for SF was detected ( r=-0.44, p=0.44). Linearly transformed scores from the two instruments differed considerably from -13 (95%CI -51 to 24) points (QoL) to 10 (-38 to 58) points (PF).

CONCLUSION

Although EORTC-QLQ-C30 scores and GIQLI scores from patients undergoing elective colorectal cancer surgery did correlate well, the level of agreement between the two instruments was quite low. Perioperative QoL data from the two instruments cannot be compared with each other.

Current Outcome of Elective Open Repair for Infrarenal Abdominal Aortic Aneurysm

The outcome of conventional elective open repair for infrarenal abdominal aortic aneurysm (AAA) has improved mainly as a result of screening to detect coronary artery disease, the main risk factor for morbidity and mortality. Our group's policy is to perform routine coronary angiography in patients scheduled to undergo elective AAA repair. The purpose of this study was to evaluate morbidity and mortality in our department using this work-up strategy. From January 1990 to December 2000 we performed elective open repair on 632 patients, including 580 men (92%) and 52 women (8%). Preoperative coronary angiography performed in 607 cases (96%) revealed significant coronary disease in 53% of patients and led to the decision to propose prior myocardial revascularization in 12.5% of cases. Mortality and morbidity in the first 30 days after AAA repair were 1.4% and 15%, respectively. Analysis with the Cox model showed that the only risk factor for mortality was chronic renal insufficiency. Our data support routine use of coronary angiography prior to AAA repair. Screening and, if necessary, treatment of coronary artery disease that is commonly associated with AAA enhances the outcome of open AAA repair.

Oxytocin Requirements at Elective Cesarean Delivery: A Dose-Finding Study

OBJECTIVE

Oxytocin is frequently used by intravenous bolus and infusion to minimize blood loss and prevent postpartum hemorrhage at cesarean delivery. Current dosing regimens are arbitrary whereas large doses may pose a serious risk to the mother. The purpose of this study was to estimate the minimum effective intravenous bolus dose of oxytocin (ED90) required for adequate uterine contraction at elective cesarean in nonlaboring women.

METHODS

A randomized, single-blinded study was undertaken in 40 healthy term pregnant women presenting for elective cesarean under spinal anesthesia. Oxytocin was administered by bolus according to a biased coin up-and-down sequential allocation scheme with increments or decrements of 0.5 IU. Uterine contraction was assessed by the obstetrician, who was blinded to the dose of oxytocin, as either satisfactory or unsatisfactory. After achieving sustained uterine contraction, an infusion of 40 mU/min of oxytocin was started. Oxytocin-induced adverse effects and intraoperative complications were recorded and blood loss was estimated. Data were interpreted by parametric analysis based on logistic regression model and nonparametric analyses at 95% confidence intervals (CIs).

RESULTS

The ED90 of oxytocin as determined by logistic regression model fitted to the data was estimated to be 0.35 IU (95% CI 0.18-0.52 IU), with nonparametric estimates of 97.1% (95% CI 84.9-99.8%) response rate at 0.5 IU, and 100% (95% CI 92.2-100%) at 1.0 IU. The estimated blood loss was 693 +/- 487 mL (mean +/- standard deviation).

CONCLUSION

The bolus dose of oxytocin used at elective cesarean deliveries in nonlaboring women can be significantly reduced while maintaining effective uterine contraction. Alteration in practice will likely reduce the potential adverse effects of this drug when given in large bolus doses, but may require modification of the techniques to remove the placenta.

Cerebrovascular carbon dioxide reactivity with propofol anesthesia in patients with previous stroke

STUDY OBJECTIVE

To examine whether patients with previous stroke have impaired cerebrovascular carbon dioxide (CO2) reactivity when receiving propofol anesthesia.

DESIGN

Prospective, controlled study.

SETTING

University hospital.

PATIENTS

34 consecutive patients, 17 of whom had previous stroke and were scheduled for elective cardiac surgery, and 17 control age-matched patients without previous stroke who were also scheduled for cardiac surgery.

INTERVENTIONS

Anesthesia was induced and a 2.5-MHz pulsed transcranial Doppler probe was attached to the patient's head at the right temporal window. Mean blood flow velocity of the middle cerebral artery (Vmca) was measured continuously.

MEASUREMENTS

After establishing baseline Vmca, arterial blood gases and cardiovascular hemodynamic values, partial pressure of end-tidal CO2 (PETCO2) was increased by changing the ventilatory frequency by 2 to 5 breaths/min. The measurements were repeated when PETCO2 increased and remained stable for 5 to 10 minutes.

MAIN RESULTS

Values for absolute CO2 reactivity in the control patients and in those with previous stroke were 2.6 +/- 0.5 and 2.9 +/- 0.7 cm/sec/mmHg, respectively, a nonsignificant difference in these values. Values for relative CO2 reactivity in control patients and in patients with previous stroke were 6.4 +/- 1.4 and 6.1 +/- 1.4%/mmHg, respectively, with no significant difference noted.

CONCLUSIONS

Cerebrovascular CO2 reactivity in patients with previous stroke is normal during propofol anesthesia.