Low-dose Propofol Research Articles

Rapid Sequence Intubation with Remifentanil During COVID-19 Pandemic

We greatly appreciate the interest that De Melo MS, et al. showed on the use of remifentanil in a rapid sequence intubation technique that we recently proposed for patients undergoing surgery during the current SARS-CoV-2 pandemic [1, 2]. The authors also reported the response that Tang and Wang wrote to comment on that paper [3]. Given the interest aroused by our article, we think it would be worth making some clarifications. In brief, in order to limit aerosolization, we proposed to systematically perform rapid induction and intubation in the surgical patient after he had reached a state of deep analgesia with a continuous infusion of high-dose remifentanil (0.2-0.3 g/kg/min) [2]. Although in the title of the article this method is labeled as a rapid sequence induction, in the text, we explain how this technique, far from being standard rapid sequence intubation, was a rather longer technique in which the patient, although in a state of profound analgesia and sedation induced by remifentanil, breathed spontaneously and at last on command, until hypnosis, and muscle paralysis was rapidly induced with a low dose of propofol (<0.5 mg/kg) or midazolam (0.05-0.1 mg/kg) and a full dose of rocuronium (1 mg/kg) [2].

The Effect of Propofol Anesthesia on the Pain Severity and Frequency of Migraine Attacks in Patients with Chronic Migraine Headache over a Six Month Follow Up: An Observational Study.

Propofol is a short-acting intravenous anesthetic that is commonly used for induction and maintenance of anesthesia. Subanesthetic low doses of propofol has also been used to treat intractable migraine attacks in emergency wards with dramatic results. However, there is little information on the long-term efficacy of this drug in migraine headaches. The aim of this nonrandomized prospective observational study was to assess the effect of propofol anesthesia on the pain severity and frequency of migraine attacks in a 6-month follow-up period after anesthesia in patients with migraine headaches. The study was conducted on 51 known cases of migraine ranging in age from 21 to 66 years. Before anesthesia, patients completed a questionnaire including their characteristics, pain intensity of the headache using a visual analog scale, and a number of headache repetitions per month. All patients received propofol as the main anesthetic agent. At the end of anesthesia, the total amount of propofol usage was recorded. Patients were then followed up by telephone in the first, third, and sixth months after anesthesia, and the severity and frequency of the headache were recorded. Pain intensity or pain frequency significantly improved in 22 patients (43.1%), remained unchanged in 24 (47%), and worsened in 5 cases (9.8%) 6 months after anesthesia compared to before the anesthesia. In conclusion, since about half of the patients had significant improvement in the headache, propofol anesthesia may be considered as an acceptable anesthetic method in patients with migraine.

Lower-Dose Propofol Use for MRI: A Retrospective Review of a Pediatric Sedation Team's Experience.

The aim of the study was to evaluate, in children undergoing procedural sedation for magnetic resonance imaging (MRI) scans, whether lower doses of propofol than previously published permitted a high rate of successful MRI completion, whether lower dosages result in a more rapid recovery, and whether age or behavioral diagnosis increases propofol requirements. After institutional review board approval, we retrospectively reviewed the pediatric sedation team's sedation database of children receiving propofol infusion for MRI scans between 2007 and 2016. Data collected included propofol induction dose (in milligrams per kilogram), propofol infusion dose (in micrograms per kilogram per hour), total propofol dose (in milligrams per kilogram and in milligrams per kilogram per hour), and the number of administered ancillary sedative medications. Additional data included the American Society of Anesthesiologist status, sedation duration, recovery duration, and successful completion of MRI. Dosing data were also stratified by age. A total of 2354 patients met inclusion criteria. Eight percent of patients received propofol infusion alone, 79% received midazolam before their propofol induction, and 13% received a combination of propofol and other drugs. Mean induction dose was 2.2 + 0.9 mg/kg, mean infusion dose was 93.5 + 29.0 μg/kg per minute, and total mean dose was 9.0 + 3.0 mg/kg per hour. Mean recovery time was 44 minutes, and 99.3% of the scans were completed with good images. We noted an increase requirement in the mean induction dose and total dose in children younger than 1 year. Propofol infusion doses lower than commonly reported permit successful completion of scans and similar recovery times in a single institution. Younger children require more propofol for successful procedural sedation.

Empirical ratio of the combined use of S-ketamine and propofol in electroconvulsive therapy and its impact on seizure quality

Electroconvulsive therapy (ECT) is an effective treatment for depressive disorders. In certain cases, ECT-associated anaesthesia can be improved by the use of ketofol (i.e., S-ketamine + propofol). We aimed to evaluate the empirical mixing ratio of ketofol in these cases for better clinical implementation. We retrospectively investigated n = 52 patients who received 919 ECT sessions with S-ketamine plus propofol as anaesthetic agents. Several anaesthesia and ECT-related parameters including doses of S-ketamine and propofol were analysed. The mean empirically determined S-ketamine/propofol ratio was 1.38 (SD ± 0.57) for 919 individual ECT sessions and 1.52 (SD ± 0.62) for 52 patients, respectively. The mean relative dose was 0.72 (± 0.18) mg/kg S-ketamine and 0.54 (± 0.21) mg/kg propofol. Higher propofol dose was associated with poorer seizure quality. Seizure quality and time in recovery room were significantly influenced by age. Ketofol could be an option to exploit the advantageous qualities of S-ketamine and propofol, if both doses are reduced compared with single use of S-ketamine or propofol. Patients with poor seizure quality may benefit from lower propofol doses, which are applicable by the addition of ketamine. An empirically determined mixing ratio in favour of ketamine turned out to be preferable in a clinical setting. Recovery time was primarily prolonged by higher age rather than by ketamine dose, which had previously often been associated with a prolonged monitoring time in the recovery room. These new findings could improve electroconvulsive therapy and should be replicated in a prospective manner.

Anesthetic Management in Bilateral Deep Brain Stimulation for X-linked Dystonia Parkinsonism: Early Single Institution Experience from the Philippines

X-linked dystonia-parkinsonism (XDP) is a rare, adult-onset, progressive, hereditary neurological movement disorder primarily affecting Filipino men with maternal families from Panay province of the Philippines. Medical treatment modalities currently being used have offered temporary symptomatic relief. Surgical management in the form of bilateral globus pallidi internae (Gpi) deep brain stimulation (DBS) has shown promising results and is increasingly being performed in advanced centers, as reported in international literature. Presented herein is the local experience of seven (7) retrospectively reviewed cases from February 2018 to February 2019 in a tertiary center in the Philippines with a particular focus on anesthetic management. All patients were male, from Panay, and presented with progressive dystonia and parkinsonism. All patients underwent planned bilateral, simultaneous DBS electrode, and implantable pulse generator (IPG) placement performed by a multidisciplinary team. Anesthetic management consisted of Bispectral Index (BIS) guided conscious sedation with low dose propofol and remifentanil infusions with a complete scalp nerve block (SB) at the start of the procedure then shifted to awake monitored anesthesia care during electrode placement, microelectrode recording (MER) and macro stimulation testing. All were put under general anesthesia with a supraglottic airway device during the placement of the internal pulse generator (IPG) in the infraclavicular area. All seven patients had successful localization, and insertion of the DBS electrode and discharged improved. The anesthetic management of the DBS used in these cases warrants further investigation and may lead to standardization of future practice.

Effects of Low-dose Propofol or Ketamine on Coughing at Emergence from Anesthesia in Children Undergoing Tonsillectomy.

IntroductionCoughing is commonly observed during emergence from general anesthesia. In children, smooth emergence from anesthesia, especially after tonsillectomy, is crucial. In this study, we compared the effect of low-dose ketamine or propofol on emergence coughing in children undergoing tonsillectomy.MethodsIn this randomized clinical trial, 90 children undergoing tonsillectomy were randomly allocated into two groups: children in group A received 0.5-mg/kg propofol and children in group B received 0.5-mg/kg ketamine, at the end of anesthesia. The incidence and severity of cough, postoperative sedation, nausea, and vomiting, and pain score were recorded and compared.ResultsThe incidence of no cough at emergence from anesthesia was 82.2% in the propofol group and 15.5% in the ketamine group (P = 0.00). Children in the ketamine group exhibited postoperative pain but were more sedated compared with those in the propofol group (P > 0.05). The incidence of postoperative nausea and vomiting was lower in the propofol group (P < 0.05).ConclusionsAt the end of general anesthesia with isoflurane in children undergoing tonsillectomy, 0.5-mg/kg propofol is more effective than 0.5-mg/kg ketamine in reducing cough response upon emergence from anesthesia, with a lower incidence of nausea and vomiting, as well as lower sedation in children.

Isoflurane alone versus small dose propofol with isoflurane for removal of laryngeal mask airway in children-a randomized controlled trial.

To compare the safety of laryngeal mask airway removal using two different deep anaesthesia techniques in paediatric patients. The Randomized Control Trial was conducted at Aga Khan University Hospital, Karachi, from April 2012 to November 2013, and comprised patients aged 2-10 years scheduled for infraumbilical surgeries. Anaesthesia was induced with sevoflurane and later it was maintained by is oflurane, oxygen and nitrous oxide. The laryngeal mask airway was removed in the intervention group-I at 0.4 minimum alveolar concentration of isoflurane with propofol 1mg/kg. In the control group-II, it was removed at 1.2 minimum alveolar concentration of isoflurane alone. SPSS 19 was used for data analysis. Of the 50 patients, there were 25(50%) in each of the two groups. Overall, there were 46(92%) males and 4(8%) females. Incidence of airway obstruction and teeth clenching was significantly higher in group-II (p<0.05 each). Emergence duration was also significantly increased in group-II compared to group-I (p=0.001). The Post-Anaesthesia Care Unit stay timing was not significantly different between the groups (p=0.74). Laryngeal mask airway removal under deep anaesthetic technique of low-dose propofol with isoflurane was found to be associated with minimal adverse airway events than isoflurane alone in paediatric patients.

Propofol affects the biological behavior of ovarian cancer SKOV3 cells via ERK1/2-MMP-2/9 signaling pathway

Purpose: To investigate the effect of propofol on the biological behavior of ovarian cancer SKOV3 cells, and the mechanism of action involved.&#x0D; Methods: SKOV3 cells cultured in vitro were randomly divided into control group, fat emulsion group, low-dose propofol group (LDPG, 25 μmol/L), medium-dose propofol group (MDPG) (50 μmol/L) and high-dose propofol group (HDPG) (100 μmol/L). Apoptosis was determined by flow cytometry, while Transwell assay was used to measure the migration and invasion abilities of the cells. The protein levels of ERK1/2, MMP-2, MMP-9 were assayed with Western blotting. Moreover, the cells were transfected with siERK, and the regulatory effect of propofol on ERK1/2-MMP-2/9 signaling pathway was determined.&#x0D; Results: Apoptosis in HDPG was significantly reduced, relative to MDPG, while migration and invasion were enhanced, relative to MDPG (p &lt; 0.05). Moreover, MMP-2, ERK1/2, and MMP-9 proteins were significantly higher in MDPG and HDPG than in control, fat emulsion and LDPGs (p &lt; 0.05), and were upregulated in HDPGs, relative to MDPG (p &lt; 0.05). In contrast, propofol did not up-regulate these proteins in siRNA-treated cells.&#x0D; Conclusion: Propofol enhances the migration, proliferation, and invasive ability SKOV3 cells, and upregulates the expressions of MMP-2, ERK1/2, and MMP-9 in these cells, via a mechanism related to the activation of ERK1/2-MMP-2/9 signaling route. These properties provide novel leads for the development of new drugs for ovarian cancer&#x0D; Keywords: Propofol, ERK1/2-MMP-2/9 signal route, Ovarian cancer, Biological behavior

Propofol sedation with a target-controlled infusion pump in elderly patients undergoing ERCP

Advanced age is an important risk factor for adverse events (AEs) during propofol sedation for endoscopic procedures. This study aimed to evaluate the safety and efficacy of nonanesthesiologist-administered propofol (NAAP) sedation with a target-controlled infusion (TCI) system in elderly patients during ERCP. This study retrospectively analyzed 482 patients who underwent ERCP under propofol sedation with a TCI system at Iwakuni Medical Center between January 2014 and October 2016. Patients were divided into 3 groups according to their age: group A,<70 years (n= 130); group B,≥70 and<85 years (n= 224); and group C,≥85 years (n= 125). We compared the propofol dose and AEs during ERCP. The median total infusion dose and minimum and maximum target blood concentrations of propofol were 336 mg, 2.2 μg/mL, and 2.2 μg/mL in group A; 184 mg, 1.0 μg/mL, and 1.4 μg/mL in group B; and 99 mg, .6 μg/mL, and 1.0 μg/mL in group C, respectively, with older groups requiring a lower dose (P< .0001). Hypotension was observed in 23 patients (4.8%), with no significant difference between groups (group A, 2.3%; group B, 6.3%; group C, 4.8%; P= .24). Hypoxemia was observed in 16 patients (3.3%), with no significant difference between groups (group A, 3.1%; group B, 4.9%; group C, .8%; P= .17). All AEs were immediately resolved, and no procedures were aborted. NAAP sedation with a TCI system during ERCP may be acceptable in elderly patients with a lower dose of propofol than that used in younger patients.

Propofol infusion syndrome; are high doses always required?

Propofol infusion syndrome is a rare condition that mainly affects critically ill patients who receive high doses of this hypnotic for a long time. We describe the case of a patient who presented hepatotoxicity in the immediate postoperative period of two surgeries in which she had received conventional doses of propofol for a short period of time. After studying the patient and monitoring her evolution, we arrived at a differential diagnosis of propofol infusion syndrome due to increased susceptibility. This syndrome should be considered in patients presenting hepatotoxicity in the immediate postoperative period, even when low doses of propofol have been administered.

Effects of different doses of propofol on the growth and expression of PCNA, CD34 and pAKT proteins in xenografted tumor of BALB/C mice with liver cancer.

To observe the effects of different doses of propofol on the growth of transplanted liver tumor in BALB/C mice and check the expression of PCNA, CD34 and pAKT proteins to clarify the mechanism on molecule level. Human primary liver cancer cells SMMC-7721 were subcutaneously cultured in BALB/C mice, and the transplanted tumor model of BALB/C mice was constructed. Forty mice successfully modeled were randomly divided into 5 groups (n = 8): the blank control group (group C), low-fat milk group (group I), low-dose (50mg/kg) propofol group (P1), middle-dose (100mg/kg) propofol group (P2) and high dose (150mg/kg) propofol group (P3). Tumor volume changes were observed at 3, 6, 9, 12, 15 and 18days (T1, T2, T3, T4, T5, T6 and T7) before and after administration of the drug, and tumor growth curves were plotted. After 19days of administration, all mice were killed for tumor collection, tumor weight was measured, and the tumor inhibition rate of propofol was calculated. The protein expression of cluster of differentiation 34 (CD34) in transplanted tumor was detected by immunohistochemistry, and the protein expression of proliferating cell nuclear antigen (PCNA) and phospho-Akt (pAKT) was detected by immunofluorescence. Compared with group C, there was no significant difference in tumor volume in group I. At T2 ~ 7, the tumor volume of group P1, P2 and P3 decreased successively (P < 0.05). There was no significant difference in the inhibitory rate of tumor in group I, and the inhibitory rate of tumor in group P1, P2 and P3 increased successively (P < 0.05). There was no significant difference in PCNA, CD34, and pAKT protein expression in group I, while PCNA, CD34, and pAKT protein content in P1, P2, P3 groups were successively decreased (P < 0.05). Propofol had a dose-dependent effect on the growth of liver cancer xenografts in mice, inhibiting the expression of PCNA, CD34 and pAKT proteins, and the effect was most obvious in the 150mg/kg propofol group.

Effects of propofol on LC3II and mTOR/p-mTOR expression during ischemia-reperfusion myocardium injury in rats with type 2 diabetes mellitus.

To investigate the effects of propofol on myocardial ischemia reperfusion in rats with type 2 diabetes, male adult rats were divided into five groups: Sham-operation (CC), ischemia-reperfusion (CI), low-dose propofol (LP), moderate-dose propofol (MP) and high-dose propofol (HP). The LP, MP and HP groups were administered with 6, 12 and 24 mg/kg/h propofol, respectively, prior to occlusion. Heart rate (HR), left ventricular systolic pressure (LVSP) and the rate (dp/dt max) of left ventricular pressure rise in early systole (±dp/dt max) were recorded. The role of autophagy was also studied by measuring the levels of superoxide dismutase (SOD), malondialdehyde (MDA), autophagy marker protein LC3II, mammalian target of rapamycin (mTOR)/phosphorylate (p)-mTOR and cardiac troponin T (cTnT). The myocardial morphological features were assessed using light and electron microscopy. The present results demonstrated that the HR, LVSP, +dp/dt and -dp/dt levels in the propofol groups (LP, MP and HP) were significantly increased (P<0.05) when compared with the CI group. The myocardial cells in the MP group showed mild edematous changes and partially dissolved mitochondrial cristae and membrane rupture. SOD, cTnT and MDA levels were significantly decreased (P<0.05), mTOR expression decreased significantly (P<0.05) and p-mTOR expression increased significantly in the MP group (P<0.05). The present study demonstrated the protective effects of propofol in T2DM rats exhibiting MIRI, with an optimal protective effect at an infusion rate of 12 mg/kg/h. Additionally, the results revealed that propofol led to significant reductions in LC3II and mTOR serum levels and the inhibition of autophagy in myocardial cells.

Reducing postoperative nausea and vomiting in pediatric patients undergoing anterior cruciate ligament reconstruction: A quality report.

Postoperative nauseaand vomiting after elective outpatient surgery can complicate discharge and increase patient suffering. Within our hospital system, there was variability in the use ofpostoperative nausea and vomiting prophylaxis for patients undergoing anterior cruciate ligament reconstruction, which resulted in variable outcomes. To address this variability, we designed and implemented a standardized postoperative nausea and vomitingprophylaxis guideline for the care of this surgical population. We sought to develop and implement a standardized postoperative nausea and vomitingprophylaxis guideline for all patients presenting for elective ambulatory anterior cruciate ligament reconstruction with the goal of reducing the rate of emesis to ≤5%. We convened a multidisciplinary team to develop a postoperative nausea and vomitingprophylaxis guideline which included administration of dexamethasone, ondansetron, and a low-dose propofol infusion in addition to a femoral and sciatic nerve block and routine ketorolac administration for pain control. Our primary outcome, emesis rate, was tracked using a P-chart. Process measures included use of guideline medications and balancing measures included opioid administration, pain scores, and emergence time. We analyzed postoperative nausea and vomitingoutcomes for 817 patients from January 1, 2014, to December 31, 2018. The baseline postoperative emesis rate for all anesthetizing locations was 17%. Following, guideline implementation, the emesis rate decreased to 5%. Opioid administration was decreased following guideline implementation. The percentage of patients managed without any perioperative opioids increased from 16% in the baseline group to 38% following guideline implementation. The P-chart suggests that the observed reduction in emesis rate represents special cause variation and this reduction was sustained over a two-year period. Implementation of standard postoperative nausea and vomitingguidelines for adolescents undergoing outpatientanterior cruciate ligament reconstruction was associated with lower emesis rates. This reduction in emesis rate may have been due to the concurrent reduction in opioids we observed following guideline implementation.

A Review of Current Literature of Interest to the Office-Based Anesthesiologist.

A Review of Current Literature of Interest to the Office-Based Anesthesiologist.

Can Propofol Lead to an Increase in Seizure Threshold Over the Course of Electroconvulsive Therapy?

ObjectiveTo evaluate the effects of 2 different dose regimens of propofol (low dose: < 1 mg/kg, high dose: ≥ 1 mg/kg) on the duration of the seizures, the required energy for the seizures, and the seizure threshold over the course of electroconvulsive therapy (ECT).MethodsThe electronic medical records of 165 patients receiving 971 sessions of ECT were analyzed retrospectively. Patients were evaluated in two groups according to the according to propofol doses that they had received for ECT. Group LP (n = 91): patients who received low dose propofol (< 1 mg/kg). Group HP (n = 74): patients who received high dose propofol (≥1 mg/kg).ResultsThe required energy for seizures in Group HP were significantly higher than the Group LP in the 3rd, 4th, 5th, 6th, 7th, 8th, and 9th sessions (p < 0.05). The duration of seizures in the Group HP were significantly lower than the Group LP in the 1st, 2nd, 4th, 5th, 7th, and 8th sessions (p < 0.05). Higher electrical stimulus was needed to acquire a minimum length of seizure (> 25 sn) during the course of ECT in higher propofol doses. Although there was an increase in the seizure threshold over the course of ECT in both groups, this increase was found to be much more pronounced in the high-dose propofol group according to the low-dose propofol group. Longer duration of seizures was observed in the low-dose propofol group.ConclusionHigher doses of propofol in induction of anesthesia can lead to a more progressive rise in seizure threshold than lower doses of propofol.

Feasibility of sedation on demand in Taiwan using water exchange and air insufflation: A randomized controlled trial.

Completion of colonoscopy without sedation eliminates sedation cost and complications. Reported in the United States and Europe, on-demand sedation is not routine practice in Taiwan. Water exchange (WE), characterized by infusion and nearly complete removal of infused water during insertion, reduces insertion pain compared to air insufflation (AI) during colonoscopy. We evaluated the feasibility of on-demand sedation in Taiwan. In a randomized controlled trial of WE vs AI colonoscopy, we also aimed to determine if WE augmented the implementation by reducing insertion pain and decreasing sedation requirement. This prospective patient-blinded study randomized patients to AI or WE (75 patients/group) to aid insertion. The primary outcome was the proportion of patients completing without sedation. In the AI and WE groups, 76.0% and 93.3% (P=0.006) completed without need for sedation, respectively. The WE group had lower insertion pain score (mean [SD]) (4.0 [2.9] vs 2.1 [2.6], P<0.001), lower doses of propofol (25.7 [52.7] mg vs 9.1 [35.6] mg, P=0.012), and less time in the recovery room (3.4 [7.4] vs 1.5 [5.5], P=0.027) than the AI group. Patient satisfaction scores and willingness to repeat if needed in the future were similar. On-demand sedation was feasible in Taiwan. The completion rate without sedation was high in patients (76.0% with standard AI) open to the option (no prior intent to receive the standard of full or minimal sedation). WE augmented the implementation by reducing insertion pain and decreasing sedation requirement without adversely affecting patient satisfaction or willingness to repeat.

Nitrous oxide anesthetic versus total intravenous anesthesia for functional endoscopic sinus surgery.

Functional endoscopic sinus surgery is a common procedure for sinonasal disease, frequently performed in the outpatient setting. General anesthesia maintained with total intravenous anesthesia (TIVA) with propofol has been shown to give superior surgical conditions compared to inhaled anesthetics. This study evaluated the effects of TIVA versus a predominantly nitrous oxide (N2 O)-based anesthetic with a low-dose propofol and remifentanil infusion on sinus surgery. Patients were randomized to either a N2 O-based (nitrous oxide with propofol and remifentanil) or TIVA (propofol and remifentanil without nitrous oxide) group. The surgeon was blinded to the anesthetic technique. Surgical field grading was performed in real time by the otolaryngologist every 15 minutes with the Boezaart grading system. There were no statistically significant differences between the Boezaart scores, duration of surgery, or estimated blood loss between the two anesthetic techniques. However, the use of N2 O provided a statistically significant, 38% reduction in time from surgery end to extubation. The TIVA group had significantly decreased mean and median pain scores in the post-anesthesia care unit (PACU). There was no difference in the rate of postoperative nausea and vomiting between the two groups. A N2 O-based anesthetic for functional endoscopic sinus surgery provides similar intraoperative and postoperative conditions when compared to TIVA, while being superior in terms of time to extubation. Although the TIVA group had significantly decreased pain scores, this did not lead to a decrease in pain medicine received in the PACU, and there was no difference between groups in time to discharge. 1b Laryngoscope, 130:E299-E304, 2020.

Analgesia-first sedation in critically ill adults: A U.S. pilot, randomized controlled trial

PurposeTo determine the feasibility of conducting a multicenter ICU RCT of AFS compared to either protocol-directed sedation (PDS) or both PDS and daily sedation interruption (DSI) in North America. Materials and methodsThis single-center RCT compared AFS [fentanyl (bolus ± infusions) to reach CPOT ≤2; if RASS ≥1, CPOT ≤2 and additional fentanyl failed to reach RASS goal (−2 to 0), low-dose propofol (up to 6 h) was given] with either PDS or both PDS and DSI daily in adults mechanically ventilated (MV) ≥48 h. Relevant feasibility, safety, and clinical outcomes were defined and evaluated. Results90 of 160 eligible patients were enrolled [AFS = 27; PDS = 28; PDS + DSI = 31]; rate = 3/month. Time from intubation to randomization was 17.5 ± 11.6 h. Study days fully adherent to the study intervention [AFS = 95%; PDS = 99%; PDS + DSI = 96%] and time spent in the first 48 h after randomization without pain (CPOT ≤2)[AFS = 82%; PDS = 78%; PDS + DSI = 77%] and at goal RASS[AFS = 88%; PDS = 83%; PDS + DSI = 95%] were high and similar. Nurse-perceived [median (IQR)] study workload (10-point VAS) was higher with AFS [4(2–6)] than PDS [1(1–3)] or PDS + DSI [2(1–5)]; p = .002). Unplanned extubation was rare (AFS = 1; PDS = 0; PDS + DSI = 1). Days [median (IQR)] free of MV in the 28d after intubation [AFS 24(23,26); PDS 24(20,26); PDS + DSI 24(21,26)] was not different (p = .62). ConclusionA multicenter RCT evaluating AFS is feasible to conduct in North America.

Endoscopist-Directed Propofol as an Adjunct to Standard Sedation: A Canadian Experience

ABSTRACTBackgroundSedation practices vary widely by region. In Canada, endoscopist-directed administration of a combination of fentanyl and midazolam is standard practice. A minority of cases are performed with propofol.AimsTo describe the safety of nonanaesthetist administered low-dose propofol as an adjunct to standard sedation.MethodsThis was a single-centre retrospective study of patients having undergone endoscopic procedures with propofol sedation between 2004 and 2012 in a teaching hospital in Montreal. Procedures were performed by gastroenterologists trained in Advanced Cardiovascular Life Support. Sedation was administered by intravenous bolus by a registered nurse, under the direction of the endoscopist. Outcomes of procedures were collected in the context of a retrospective chart review using the hospital’s endoscopy database.ResultsOf patients undergoing endoscopies at our centre, 4930 patients received propofol as an adjunct to standard sedation with fentanyl and midazolam. Cecal intubation rate for colonoscopies (n = 2921) was 92.0%. Gastroscopies (n = 1614), flexible sigmoidoscopies (n = 28), endoscopic retrograde cholangiopancreatography (n = 331) and percutaneous endoscopic gastrostomy insertion (n = 36) had success rates, defined as successful completion of the procedure within anatomical limits, of 99.0, 96.4, 94.0 and 91.7%, respectively. The average dose of propofol used for each procedure was 34.5 ± 20.8 mg. Fentanyl was used in 67.4% of procedures at an average dose of 94.3 ± 17.5 mcg. Midazolam was used in 92.7% of cases at an average dose of 3.0 ± 0.7 mg. Reversal agents (naloxone or flumazenil) were used in 0.43% of the cases (n = 21). Patients who received propofol were discharged uneventfully within the usual postprocedure recovery time. One patient required sedation-related hospitalization. For patients having received propofol in addition to standard sedation agents, 99.6% experienced no adverse events. There were no mortalities.ConclusionThe use of low-dose propofol as an adjunct to fentanyl and midazolam, administered by a registered nurse under the direction of the endoscopist was safe and effective in patients at our centre.

Hypoventilation patterns during bronchoscopic sedation and their clinical relevance based on capnographic and respiratory impedance analysis.

Capnography involves the measurement of end-tidal CO2 (EtCO2) values to detect hypoventilation in patients undergoing sedation. In a previous study, we reported that initiating a flexible bronchoscopy (FB) examination only after detecting signs of hypoventilation could reduce the risk of hypoxemia without compromising the tolerance of the patient for this type of intervention. We hypothesize that hypoventilation status could be determined with greater precision by combining thoracic impedance-based respiratory signals, RESP, and EtCO2 signals obtained from a nasal-oral cannula. Retrospective analysis was conducted on RESP and EtCO2 waveforms obtained from patients during the induction of sedation using propofol for bronchoscopic examination in a previous study. EtCO2 waveforms associated with hypoventilation were then compared with RESP patterns, patient variables, and sedation outcomes. Signals suitable for analysis were obtained from 44 subjects, 42 of whom presented indications of hypoventilation, as determined by EtCO2 waveforms. Two subtypes of hypoventilation were identified by RESP: central-predominant (n = 22, flat line RESP pattern) and non-central-predominant (n = 20, RESP pattern indicative of respiratory effort with upper airway collapse). Compared to cases of non-central-predominant hypoventilation, those presenting central-predominant hypoventilation during induction were associated with a lower propofol dose (40.2 ± 18.3 vs. 60.8 ± 26.1mg, p = 0.009), a lower effect site concentration of propofol (2.02 ± 0.33 vs. 2.38 ± 0.44µg/ml, p = 0.01), more rapid induction (146.1 ± 105.5 vs. 260.9 ± 156.2s, p = 0.01), and lower total propofol dosage (96.6 ± 41.7 vs. 130.6 ± 53.4mg, p = 0.04). Hypoventilation status (as revealed by EtCO2 levels) could be further classified by RESP into central-predominant or non-central-predominant types. It appears that patients with central-predominant hypoventilation are more sensitive to propofol during the induction of sedation. RESP values could be used to tailor sedation management specifically to individual patients.