Postoperative Propofol Research Articles

Predictive value of Bispectral Index (BIS) in emergency neurosurgical patients: Loss of BIS reactivity to propofol predicts poor functional outcomes

AimIn emergency neurosurgical patients, evaluation with Glasgow Coma Scale (GCS) alone immediately after stopping sedation post-operatively might not differentiate those with good recovery from those with poor outcomes at 3 months. This study aimed to evaluate the prognostic value of measuring the Bispectral Index (BIS) and the correlation to propofol dosage during the use of sedation in the early post-operative period. MethodsThis is a prospective study on consecutive post-operative neurosurgical patients admitted to the neurosurgical ICU on propofol sedation. The primary outcome was the correlation between early post-operative BIS and the Propofol dosage with the modified Rankin scale (mRS) at 3 months. Secondary outcomes included the post-operative propofol requirement in patients with good functional outcomes (mRS 0–3) versus poor functional outcomes (mRS 4–6) at 3 months. ResultsIn total, 728 BIS readings were collected from twenty-four patients for analysis. The BIS readings were significantly correlated to the propofol dosage in patients with good function outcomes at 3 months (p < 0.0001). BIS readings in patients with no associations to changes in propofol dosage during their ICU stay had poor outcomes (mRS 4–6) at 3 months (r = −0.0407). For patients with good functional outcomes at 3 months, a significantly higher propofol dosage was used for deep sedation (BIS 40 – 60) during the post-operative period (p < 0.001). ConclusionFor emergency neurosurgical patients whose BIS readings had lost correlation to the propofol dosage upon recovery, their functional outcomes at 3 months were poor. For those with good functional outcomes at 3 months, a significantly higher propofol dosage was required for deep sedation during their ICU stay. Patients with preserved correlation of BIS readings to changes in propofol dosages during the early post-operative period were associated with good functional outcomes at 3 months.

Postoperative propofol bolus treatment did not affect recovery time in patients with emergence agitation after sevoflurane anesthesia in pediatric patients undergoing strabismus surgery: Prospective nonrandomized case-control study.

The incidence of emergence agitation (EA) after sevoflurane anesthesia is high, especially in pediatric strabismus surgery. However, research thus far has focused on the pharmacological prophylaxis of EA and administering drugs to pediatric patients without EA is problematic. The purpose of this study was to determine whether the use of propofol after sevoflurane anesthesia affects recovery time in patients with EA. After obtaining informed written consent, 113 children (aged 2-12 years) with the American Society of Anesthesiologists physical status of I or II who underwent strabismus surgery were enrolled. Patients were divided into 2 groups; upon arrival at the postanesthetic care unit (PACU), patients who had EA (pediatric anesthesia emergence delirium [PAED] scale score ≥14) were treated with 1.0 mg/kg 1% propofol (group P: n = 30). Patients who did not have EA (PAED scale score <14, group C: n = 83) were taken care of in the PACU without propofol administration. There was no difference in the PAED scale scores between the 2 groups from 10 minutes to discharge from the PACU (P > .05). There was no difference in PACU stay time between the 2 groups (P > .05). We concluded that propofol administration for intense EA alleviated EA symptoms and prevented an increase in the duration of PACU stay due to EA in children undergoing strabismus surgery under sevoflurane anesthesia.

Intraoperative administration of isoflurane improves survival in rats exposed to caecal ligation and puncture.

Emerging data suggest that volatile anaesthetic agents may be protective during critical illness. Three-month-old Sprague Dawley rats were randomly allocated to one of four groups: isoflurane during surgery followed by 3 days of isoflurane 0.8% (and intralipid i.v.), propofol during surgery and 314 μg kg-1 h-1 propofol for 3 days, isoflurane during surgery and intralipid for 3 days, and propofol during surgery and intralipid for 3 days. After induction with propofol or isoflurane, rats breathed oxygen 100% spontaneously via a nose cone. Propofol or intralipid was administered through a 22-gauge jugular vein i.v. catheter. Caecal ligation and puncture was performed through a paramedian incision. The surgical concentration of isoflurane was kept at 2%, and propofol was maintained at 800 μg kg-1 h-1. After recovery and 3 days of exposure to intralipid or anaesthetic agents, the rats were allowed to roam free in an adequately vented, temperature- and humidity-controlled cage with food and water ad libitum. Rats that received isoflurane for 3 days survived longer than the postoperative propofol group (P=0.0002, log-rank test). Among rats receiving no postoperative anaesthetic, those receiving isoflurane during surgery survived longer than those that received propofol during surgery group (P=0.0081). Exposure to isoflurane, as opposed to propofol, may improve survival in rats exposed to caecal ligation and puncture.

Propofol plus low-dose dexmedetomidine infusion and postoperative delirium in older patients undergoing cardiac surgery

BackgroundPostoperative delirium (POD) is a frequent complication in older patients. Dexmedetomidine might be effective in decreasing the incidence of POD. We hypothesised that adding low-dose rate dexmedetomidine infusion to a propofol sedation regimen would have fewer side-effects and would counteract the possible delirium producing properties of propofol, resulting in a lower risk of POD than propofol with placebo. MethodsIn this double-blind placebo-controlled trial, patients ≥60 yr old undergoing on-pump cardiac surgery were randomised 1:1 to the following postoperative sedative regimens: a propofol infusion and dexmedetomidine (0.4 μg kg−1 h−1) or a propofol infusion and saline 0.9% (placebo group). The study drug was started at chest closure and continued for 10 h. The primary endpoint was in-hospital POD, assessed using the Confusion Assessment Method and chart review method. ResultsPOD over the course of hospital stay occurred in 31/177 (18%) and 33/172 (19%) patients in the dexmedetomidine and placebo arm, respectively (P=0.687; odds ratio=0.89; 95% confidence interval, 0.52–1.54). The incidence of POD in the intensive care alone, or on the ward alone, was also not significantly different between the groups. Subjects in the dexmedetomidine group spent less median time in a delirious state (P=0.026). Median administered postoperative norepinephrine was significantly higher in the dexmedetomidine group (P<0.001). One patient in the dexmedetomidine group and 10 patients in the placebo group died in the hospital. ConclusionsAdding low-dose rate dexmedetomidine to a sedative regimen based on propofol did not result in a different risk of in-hospital delirium in older patients undergoing cardiac surgery. With a suggestion of both harm and benefit in secondary outcomes, supplementing postoperative propofol with dexmedetomidine cannot be recommended based on this study. Clinical trial registrationNCT03388541.

A Single Prophylactic Dose of Ondansetron Given at Cessation of Postoperative Propofol Sedation Decreases Postoperative Nausea and Vomiting in Cardiac Surgery Patients: A Randomized Controlled Trial.

Postoperative nausea and vomiting (PONV) is a common occurrence after cardiac surgery. However, in contrast to other surgical populations, routine PONV prophylaxis is not a standard of care in cardiac surgery. We hypothesized that routine administration of a single prophylactic dose of ondansetron (4 mg) at the time of stopping postoperative propofol sedation before extubation in the cardiac surgery intensive care unit would decrease the incidence of PONV. With institutional human ethics board approval and written informed consent, we conducted a randomized controlled trial in patients ≥19 years of age with no history of PONV undergoing elective or urgent cardiac surgery procedures requiring cardiopulmonary bypass. The primary outcome was the incidence of PONV in the first 24 hours postextubation, compared by the χ test. Secondary outcomes included the incidence and times to first dose of rescue antiemetic treatment administration, the incidence of headaches, and the incidence of ventricular arrhythmias. PONV within the first 24 hours postextubation occurred in 33 of 77 patients (43%) in the ondansetron group versus 50 of 82 patients (61%) in the placebo group (relative risk, 0.70 [95% confidence interval {CI}, 0.51-0.95]; absolute risk difference, -18% [95% CI, -33 to -2]; number needed to treat, 5.5 [95% CI, 3.0-58.4]; χ test, P = .022). Kaplan-Meier "survival" analysis of the times to first rescue antiemetic treatment administration over 24 hours indicated that patients in the ondansetron group fared better than those in the placebo group (log-rank [Mantel-Cox] test; P = .028). Overall, 32 of 77 patients (42%) in the ondansetron group received rescue antiemetic treatment over the first 24 hours postextubation versus 47 of 82 patients (57%) in the placebo group (relative risk, 0.73 [95% CI, 0.52-1.00]; absolute risk difference, -16% [95% CI, -31 to 1]); P = .047. There were no significant differences between the groups in the incidence of postoperative headache (ondansetron group, 5 of 77 patients [6%] versus placebo group, 4 of 82 patients [5%]; Fisher exact test; P = .740) or ventricular arrhythmias (ondansetron group, 2 of 77 patients [3%] versus placebo group, 4 of 82 patients [5%]; P = .68). These findings support the routine administration of ondansetron prophylaxis at the time of discontinuation of postoperative propofol sedation before extubation in patients following cardiac surgery. Further research is warranted to optimize PONV prophylaxis in cardiac surgery patients.

Cardioprotective efficacy of sevoflurane vs. propofol during induction and/or maintenance in patients undergoing coronary artery revascularization surgery without pump: A randomized trial

PurposePre and post-operative administration of sevoflurane in myocardial revascularization surgery provides enhanced cardioprotective effects exerted by pharmacologic pre- and post-conditioning, as compared to propofol. The identification of the enzymes involved in conditioning mechanisms is crucial to the understanding of the effects of sevoflurane in cardiac surgery patients. The impact of sevoflurane on another crucial target organ—the kidney—was also assessed. MethodsNinety patients undergoing off-pump myocardial revascularization surgery were allocated to receive either intra- and postoperative sevoflurane (SS), intraoperative sevoflurane and postoperative propofol (SP), or intra- and postoperative propofol (PP)). Troponin I and hemodynamic parameters were monitored during the first 48 postoperative hours; blood and urine samples were collected at baseline and at 24h to determine Akt, ERK1/2, PKG, iNO, bradykinin receptor, caspase 3, NT proBNP and urinary NGAL. ResultsThe enzymes were overexpressed in the SS group, remained unchanged in the SP group, and decreased in the PP group. Renal function was best preserved in the SS group. ConclusionsThe overexpression of enzymes induced by intraoperative anesthesia and postoperative sedation with sevoflurane reduces myocardial damage and improves renal function in patients undergoing off-pump myocardial revascularization surgery.

N100 Auditory Potential and Electroencephalogram Discriminate Propofol-Induced Sedation Levels

In the present study, we evaluated the electroencephalogram (EEG) and auditory N100 potential (N100) before and during propofol-induced sedation. The aim was to test whether using EEG and N100 the level of sedation may be evaluated. Twenty-nine cardiac surgery patients were studied. The EEG signal and the N100 potential were recorded at awake one day before the cardiac operation and two times after the operation, when the clinical level of postoperative propofol sedation was considered deep (Ramsay Score 6) and moderate (Ramsay Score 4). Discriminant analysis was used to select those spectral EEG and/or N100 variables which would predict the correct level of sedation best. The final classification was based on canonical discriminant functions and Mahalanobis' distance. The spectral EEG variables (slow/fast-ratio, delta, and beta2 powers) predicted the correct level of sedation with 81% (canonical discriminant functions) and 80% (Mahalanobis' distance) accuracy. Similarly, the N100 (amplitude, latency, and the first principal component) predicted the correct level of sedation with 91% and 92% accuracy, and the combination of the EEG and N100 with 96% and 93% accuracy. Our findings suggest that the combined use of EEG and N100 may help to differentiate the propofol-induced sedation levels, and thus be a useful compliment to clinical sedation scales.

Evidence of auditory processing during postoperative propofol sedation.

Our aim was to characterize cerebral event-related responses, which index the detection of auditory stimuli during postoperative sedation. We monitored auditory event-related potentials (ERPs) before and after elective cardiac operation in 29 patients. Sedation levels, induced with propofol, were evaluated clinically with Ramsay score (RS). During deep sedation (RS 6), patients could be categorized into 3 groups according to ERP responses evoked by a standard 'oddball' paradigm. In one group, there were no cortical responses indexing the detection of a sound (N100), another group showed clear responses, and the third group was characterized by a later P300a component which was taken to reflect orienting to a novel stimulus in adults who were awake. However, in deep sedation, P300a did not show behaviour characteristic to an orienting reaction. In moderate sedation (RS 4), all the patients showed a visible N100. Total sedative propofol dose, hemodynamics and the spontaneous electroencephalography (EEG) were not connected to the category of an individual's responses. The results of our study suggest that the detection and automatic auditory information processing function during postoperative sedation, and may signal the individual stages of awakening in a sensitive way. In addition, the findings suggest a deficit in sensory memory function during sedation.