Patient-maintained propofol sedation using reaction time monitoring: a volunteer safety study

Anesthetic strategy for obese patients during gastroscopy: deep sedation or conscious sedation? A prospective randomized controlled trial

OBJECTIVE

This paper aims to compare the incidence of SpO₂ values < 95% and < 90% of the obese patients between conscious sedation and deep sedation and whether conscious sedation was superior to the deep sedation for obese patients during diagnostic gastroscopy.

METHODS

Obese patients undergoing diagnostic gastroscopy were randomly assigned to two different intervention groups: group CS (conscious sedation) or group DS (deep sedation). Group CS patients were managed by conscious sedation [Modified Observer Assessment of Alertness/Sedation (MOAA/S) at 4-5] protocol, and group DS patients were managed by deep sedation (MOAA/S at ≤ 2) protocol. Propofol and sufentanil (0.1 and 0.05 mg/kg) were, respectively, infused for sedation and analgesia in CS and DS protocols. The primary endpoints were to compare the incidence of SpO₂ values < 95% and < 90% of the patients between the two groups. The incidence of successful sedation, satisfaction scores of patients and endoscopist were assessed as secondary endpoints.

RESULTS

115 obese patients (59 in group CS and 56 in group DS) were enrolled in this study. The incidences of SpO₂ < 95% and < 90% in group CS (42.4% and 6.8%) were significantly lower than those in group DS (69.6% and 19.6%, with P = 0.003 and 0.041, respectively). The incidence of successful sedation was similar between groups (86.4% vs 89.3%, P = 0.641). Patient satisfaction scores and endoscopist satisfaction scores were both similar between groups (P = 0.548 and 0.171).

CONCLUSION

Conscious sedation with propofol and sufentanil (0.1 mg/kg) reduced the incidence of hypoxic events without affecting gastroscopy procedure and satisfaction compared with the deep sedation for obese patients during diagnostic gastroscopy.

TRIAL REGISTRATION

ChiCTR-1900024894; registration date, July 31, 2019. http://www.chictr.org.cn .

Patient-maintained propofol sedation for adult patients undergoing surgical or medical procedures: a scoping review of current evidence and technology

Patient-maintained propofol sedation (PMPS) is the delivery of procedural propofol sedation by target-controlled infusion with the patient exerting an element of control over their target-site propofol concentration. This scoping review aims to establish the extent and nature of current knowledge regarding PMPS from both a clinical and technological perspective, thereby identifying knowledge gaps to guide future research. We searched MEDLINE, EMBASE, and OpenGrey databases, identifying 17 clinical studies for analysis. PMPS is described in the context of healthy volunteers and in orthopaedic, general surgical, dental, and endoscopic clinical settings. All studies used modifications to existing commercially-available infusion devices to achieve prototype systems capable of PMPS. The current literature precludes rigorous generalisable conclusions regarding the safety or comparative clinical effectiveness of PMPS, however cautious acknowledgement of efficacy in specific clinical settings is appropriate. Based on the existing literature, together with new standardised outcome reporting recommendations for sedation research and frameworks designed to assess novel health technologies research, we have made recommendations for future pharmacological, clinical, behavioural, and health economic research on PMPS. We conclude that high-quality experimental clinical trials with relevant comparator groups assessing the impact of PMPS on standardised patient-orientated outcome measures are urgently required.

Patient-Controlled Versus Clinician-Controlled Sedation With Propofol: Systematic Review and Meta-analysis With Trial Sequential Analyses

BACKGROUND

Sedation with propofol is frequently used to facilitate diagnostic and therapeutic procedures. Propofol can be administrated by the patient (patient-controlled sedation [PCS]) or by a clinician (clinician-controlled sedation [CCS]). We aimed to compare these 2 techniques.

METHODS

PubMed, Embase, CENTRAL, and trial registries were searched up to October 2017 for randomized controlled trials comparing PCS with CCS with propofol. The primary end points were the risks of presenting at least 1 episode of oxygen desaturation, arterial hypotension, and bradycardia, and the risk of requiring a rescue intervention (pharmacologic therapies or physical maneuvers) for sedation-related adverse events. Secondary end points were the dose of propofol administrated, operator and patient satisfaction, and the risk of oversedation. A random-effects model and an α level of .02 to adjust for multiple analyses were used throughout. Trial sequential analyses were performed for primary outcomes. Quality of evidence was assessed according to the Grades of Recommendation, Assessment, Development, and Evaluation system.

RESULTS

Thirteen trials (1103 patients; median age, 47 years; American Society of Anesthesiologists physical status I-III) describing various diagnostic and therapeutic procedures with propofol sedation were included. PCS had no impact on the risk of oxygen desaturation (11 trials, 31/448 patients [6.9%] with PCS versus 46/481 [9.6%] with CCS; risk ratio, 0.74 [98% confidence interval, 0.35-1.56]) but decreased the risk of requiring a rescue intervention for adverse events (11 trials, 29/449 patients [6.5%] with PCS versus 74/482 [15.4%] with CCS; risk ratio, 0.45 [98% confidence interval, 0.25-0.81]). For both outcomes, Trial sequential analyses suggested that further trials were unlikely to change the results, although the quality of evidence was graded very low for all primary outcomes. For the risk of arterial hypotension and bradycardia, the required sample size for a definitive conclusion had not been reached. Analysis of secondary outcomes suggested that PCS decreased the risk of oversedation and had no impact on propofol dose administrated, or on operator or patient satisfaction.

CONCLUSIONS

PCS with propofol, compared with CCS with propofol, had no impact on the risk of oxygen desaturation, but significantly decreased the risk of rescue interventions for sedation-related adverse events. Further high-quality trials are required to assess the risks and benefits of PCS.

A Prototype Patient-Maintained Propofol Sedation System Using Target Controlled Infusion for Primary Lower-Limb Arthroplasty

Each year, many operations in the UK are performed with the patient awake, without the use of general anaesthesia. These include joint replacement procedures, and in order to reduce patient anxiety, the supervising anaesthetist delivers the sedative propofol intravenously using a target-controlled infusion (TCI) device. However, it is clinically challenging to judge the required effect-site concentration of sedative for an individual patient, resulting in patient care issues related to over or under-sedation. To improve the process, patient-maintained propofol sedation (PMPS), where the patient can request an increase in concentration through a hand-held button, has been considered as an alternative. However, due to the proprietary nature of modern TCI pumps, the majority of PMPS research has been conducted using prototypes in research studies. In this work, a PMPS system is presented that effectively converts a standard infusion pump into a TCI device using a laptop with TCI software. Functionally, the system delivers sedation analogous to a modern TCI pump, with the differences in propofol consumption and dosage within the tolerance of clinically approved devices. Therefore, the Medicines and Healthcare products Regulatory Agency (MHRA) has approved the system as a safe alternative to anaesthetist-controlled TCI procedures. It represents a step forward in the consideration of PMPS as a sedation method as viable alternative, allowing further assessment in clinical trials.

Clinical application of a novel endoscopic mask: A randomized controlled trial in aged patients undergoing painless gastroscopy

Background: Desaturation during painless gastroscopy in aged patients leads to discontinuation of the procedure, prolonged manipulation time and increased risk of severe complications. An endoscopic nasal mask was designed to control hypoxia during the above procedures. A randomized trial was performed to test whether the novel endoscopic mask is helpful for hypoxia during painless gastroscopy in aged patients. Methods: In this randomized, controlled trial, 141 aged patients undergoing painless gastroscopy were randomized into nasal catheter group (69 patients) and endoscopic mask group (65 patients). Primary outcomes were minimum pulse oxygen saturation and incidence of pulse oxygen saturation ≤ 90%. Results: Finally, 134 aged patients were analyzed, including 69 patients in nasal catheter group and 65 patients endoscopic mask group. The minimum pulse oxygen saturation (96.4% ± 4.8%) was higher in the aged endoscopic mask group than in the aged nasal catheter group (94.3% ± 5.6%, P = 0.0075). The incidence of pulse oxygen saturation ≤ 90% did not significantly differ between the endoscopic mask group and nasal catheter group (6.2% VS 15.9%, P = 0.07). There were no severe adverse events in either groups. Conclusion: The endoscopic mask was safely used in aged patients during painless gastroscopy under propofol sedation and significantly improved the minimum pulse oxygen saturation without increasing time to examination or recovery time.

Pharmacokinetics of high-dose intravenous melatonin in humans

This crossover study investigated the pharmacokinetics and adverse effects of high-dose intravenous melatonin. Volunteers participated in 3 identical study sessions, receiving an intravenous bolus of 10 mg melatonin, 100 mg melatonin, and placebo. Blood samples were collected at baseline and 0, 60, 120, 180, 240, 300, 360, and 420 minutes after the bolus. Quantitative determination of plasma melatonin concentrations was performed using a radioimmunoassay technique. Pharmacokinetic parameters were estimated by a compartmental pharmacokinetic analysis. Adverse effects included assessments of sedation and registration of other symptoms. Sedation, evaluated as simple reaction times, was measured at baseline and 120, 180, 300, and 420 minutes after the bolus. Twelve male volunteers completed the study. Median (IQR) Cmax after the bolus injections of 10 mg and 100 mg of melatonin were 221,500.0 (185,637.5-326,175.0) pg/mL and 1,251,500.0 (864,375.0-1,770,500.0) pg/mL, respectively; mean (SD) t1/2 was 42.3 (5.6) minutes and 46.2 (6.2) minutes; mean (SD) Vd was 1.6 (0.9) L/kg and 2.0 (0.8) L/kg; mean (SD) CL was 0.0253 (0.0096) L/min · kg and 0.0300 (0.0120) L/min · kg; and median (IQR) AUC0- ∞ , 8,997,633.0 (6,071,696.2-11,602,811.9) pg · min/mL and 54,685,979.4 (36,028,638.6-105,779,612.0) pg · min/mL. High-dose intravenous melatonin did not induce sedation, evaluated as simple reaction times. No adverse effects were reported in the study.

Reaction time-monitored patient-maintained propofol sedation: a pilot study in oral surgery patients

Previous volunteer studies of an effect-site controlled patient-maintained sedation system using propofol have demonstrated a risk of oversedation. We have incorporated a reaction time monitor into the handset to add an individualised patient-feedback mechanism. This pilot study assessed if the reaction time-feedback modification would prove safe and effective in 20 healthy patients receiving sedation while undergoing oral surgery. All patients successfully sedated themselves without reaching any unsafe endpoints. All 20 maintained verbal contact throughout. The mean (SD) lowest peripheral blood oxygen saturation was 98.0 (2.1)% breathing room air. No patient required supplementary oxygen. The mean (SD) maximum effect-site propofol concentration reached was 1.6 (0.5) μg.ml(-1). The present system was found to be safe and effective, allowing oral surgery treatment under conscious sedation, but preventing oversedation.