The potential regimen of target-controlled infusion of propofol in flexible bronchoscopy sedation: a randomized controlled trial

The impact of alfentanil supplementation on the sedation of bronchoscopy: A meta-analysis of randomized controlled trials

BACKGROUND

The efficacy of alfentanil supplementation for the sedation of bronchoscopy remains controversial. We conduct a systematic review and meta-analysis to explore the influence of alfentanil supplementation on the sedation during bronchoscopy.

METHODS

We search PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases through December 2019 for randomized controlled trials (RCTs) assessing the effect of alfentanil supplementation versus placebo for the sedation during bronchoscopy. This meta-analysis is performed using the random-effect model.

RESULTS

Five RCTs are included in the meta-analysis. Overall, compared with control group for bronchoscopy, alfentanyl supplementation is associated with significantly reduced coughing scores (Std. MD = -0.55; 95% CI = -0.96 to -0.14; P = 0.009) and dose of propofol (Std. MD = -0.34; 95% CI = -0.64 to -0.04; P = 0.03), but reveals the increase in hypoxemia (RR = 1.56; 95% CI = 1.17 to 2.08; P = 0.002).

CONCLUSIONS

Alfentanyl supplementation benefits to reduce coughing scores and dose of propofol for bronchoscopy, but increases the incidence of hypoxemia. The use of alfentanyl supplementation for bronchoscopy should be with caution.

Dexmedetomidine sedation for endobronchial ultrasound-guided transbronchial needle aspiration, a randomised controlled trial

Background and aim

Appropriate sedation is important to the success of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). Dexmedetomidine is a sedative agent that operates via the α2 adrenergic agonist, which provides sleep-like sedation with little respiratory suppression. This study compared the efficacy and safety of dexmedetomidine sedation with propofol in cases of EBUS-TBNA.

Methods

Patients requiring EBUS-TBNA were randomly assigned dexmedetomidine sedation (D, n=25) or propofol sedation (P, n=25). Vital signs, diagnostic yield and the bispectral index (BIS) were recorded throughout the bronchoscopic procedure and recovery period. The tolerance and cooperation of the patients were evaluated using questionnaires.

Measurements and results

The lowest mean arterial blood pressure in group D (79.2±9.9 versus 72.5±12.9 mmHg, p=0.049) exceeded that in group P, the lowest heart rate was lower (60.9±10.2 versus 71.4±11.8 beats·min⁻¹, p=0.006) and the mean BIS during sedation was significantly higher (84.1±8.3 versus 73.6±5.7, p<0.001). Patients in group D were more likely to report perceiving procedure-related symptoms and express an unwillingness to undergo the bronchoscopy again, if indicated (41.1 versus 83.3%, p=0.007). One subject in group D aborted EBUS-TBNA due to intolerance. Many of the variables in the two groups were similar, including the proportion of hypoxaemic events, recovery times, patient cooperation and diagnostic yield.

Conclusions

The effects of dexmedetomidine on haemodynamics were in line with its pharmacodynamic features. Patients who received dexmedetomidine were more likely than those who received propofol to perceive the procedures. Overall, dexmedetomidine did not prove inferior to propofol sedation in terms of patient cooperation or diagnostic yield.

Compared to propofol sedation for EBUS-TBNA, dexmedetomidine provided patients lighter sedation with lower heart rates and less decrease in blood pressure. The recovery times, hypoxaemia, cooperation and diagnostic yield in the two groups were similar.https://bit.ly/33qgEj3

Optimal effect-site concentration of propofol for tracheal suctioning during emergence from ophthalmic surgery

In ophthalmic surgery, coughing during emergence from general anesthesia may have a detrimental effect on intraocular pressure. Tracheal suction during emergence may elicit this reflex. The optimal effect-site concentration (EC) of propofol to prevent triggering of the cough reflex during tracheal suctioning is unknown. The aim of this study is to assess the optimal EC of propofol for tracheal suctioning during emergence in patients undergoing ophthalmic surgery.Twenty-one patients were enrolled, all of them American Society of Anesthesiologists (ASA) physical status I or II non-smokers undergoing ophthalmic surgery. Anesthesia was induced and maintained under total intravenous anesthesia using target-controlled infusion. During emergence from general anesthesia, tracheal suction was performed at different propofol concentrations as required for Dixon's up-and-down method with a step size of 0.2 μg/ml. A propofol concentration at which the cough reflex was not triggered during tracheal suctioning was considered successful.The EC50 of propofol for tracheal suction without cough was 1.4 μg/ml and the EC95 was 1.6 μg/ml.Tracheal suction may be accomplished without triggering the cough reflex when the propofol effect-site concentration is higher than 1.6 μg/ml.

Anesthetic Considerations for Patients Undergoing Bronchial Thermoplasty

Bronchial thermoplasty (BT) is a novel, Food and Drug Administration-approved nondrug treatment for patients whose asthma remains uncontrolled despite traditional pharmacotherapy. BT involves application of controlled radiofrequency energy to reduce airway smooth muscle in large- and medium-sized airways. Although BT is often performed under general anesthesia, anesthetic management strategies for BT are poorly described. We describe the anesthetic management of 7 patients who underwent 19 BT treatments in a tertiary academic medical center.

A study protocol for a feasibility study: Propofol Target-Controlled Infusion in Emergency Department Sedation (ProTEDS)-a multi-centre feasibility study protocol

Background

Procedural sedation is a core skill of the emergency physician. Bolus administration of propofol is widely utilised in UK emergency departments to provide procedural sedation. Bolus administration of propofol, titrated to an endpoint of sedation, has a rapid effect but can easily result in apnoea and loss of airway patency. The use of a target-controlled infusion of propofol allows for controlled titration to an effect site concentration and may reduce the rate of adverse incidents. Target-controlled infusion of propofol is not currently used in emergency departments.The primary aim of this feasibility study is to ensure that propofol target-controlled infusion (TCI) is acceptable to the patient and that recruitment rates are adequate to power a randomised controlled trial comparing propofol target-controlled infusion versus bolus administration.

Methods

This study will recruit in four emergency departments in Scotland, UK. Patients aged 18-65 years with anterior shoulder dislocation, weighing ≥ 50 kg and fasted ≥ 90 min, will be screened. Recruited patients will undergo emergency reduction of a dislocated shoulder facilitated by procedural sedation utilising TCI of propofol.The widespread adoption of TCI propofol by emergency departments will require evidence that it is safe, potentially effective, patient centred and a timely method of providing procedural sedation. The primary endpoint will be acceptability measured by patient satisfaction. The secondary endpoints will include incidence and severity of adverse events, number of shoulder reduction attempts, nursing opinion of patient experience, patient's reported pain score and time from commencement of TCI propofol sedation to desired sedation level.The study will be open for recruitment from April 2017 to December 2018.

Discussion

If the study demonstrates patient acceptability with adequate recruitment, we will be in a position to determine the feasibility of progression to a randomised controlled clinical trial of TCI compared to bolus administration of propofol.

Trial registration

ClinicalTrials.gov Identifier: NCT03442803. Registered retrospectively on 22 February 2018.

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 ± 26.1 mg, p = 0.009), a lower effect site concentration of propofol (2.02 ± 0.33 vs. 2.38 ± 0.44 µg/ml, p = 0.01), more rapid induction (146.1 ± 105.5 vs. 260.9 ± 156.2 s, p = 0.01), and lower total propofol dosage (96.6 ± 41.7 vs. 130.6 ± 53.4 mg, 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.

Propofol-sparing effect of different concentrations of dexmedetomidine : Comparison of gender differences

Background

The pharmacodynamics of propofol are closely linked to gender. Dexmedetomidine can decrease propofol needs during propofol anesthesia. The aim of this study was to compare the gender differences on the calculated effect site median effective concentration (EC₅₀) of propofol for loss of consciousness (LOC) after pretreatment with different concentrations of dexmedetomidine.

Methods

In this study 60 male and 60 female patients were randomly allocated to receive dexmedetomidine at target plasma concentrations of 0.0 ng/ml (0.0 group), 0.4 ng/ml (0.4 group), 0.6 ng/ml (0.6 group) and 0.8 ng/ml (0.8 group). Propofol was administered after dexmedetomidine had been intravenously infused for 15 min. The propofol infusion was targeted to provide an initial effect-site concentration of 1.0 μg/ml, followed by increments by 0.2 μg/ml when the effect-site concentration and target concentration of propofol were in equilibrium until LOC was established, where LOC was defined by the observer’s assessment of alertness/sedation scale (OAA/S) score < 2.

Results

The calculated effect-site EC₅₀ of propofol LOC was higher in males than in females in the 0.0, 0.4, 0.6, and 0.8 groups (2.43 vs. 2.17, 1.99 vs. 1.82, 1.72 vs. 1.56 and 1.50 vs. 1.32 μg/ml, respectively, all p < 0.05). The hypnotic interaction between dexmedetomidine and propofol could be described with an additive model of pharmacodynamic interaction.

Conclusion

Gender significantly influenced the calculated effect-site EC₅₀ of propofol for LOC after pretreatment with different concentrations of intravenous dexmedetomidine. It was concluded that an additive interaction could describe the results seen. Thus, gender has to be considered when these drugs are co-administered.

Use of computer-assisted drug therapy outside the operating room

PURPOSE OF REVIEW

The number of procedures performed in the out-of-operating room setting under sedation has increased many fold in recent years. Sedation techniques aim to achieve rapid patient turnover through the use of short-acting drugs with minimal residual side-effects (mainly propofol and opioids). Even for common procedures, the practice of sedation delivery varies widely among providers. Computer-based sedation models have the potential to assist sedation providers and offer a more consistent and safer sedation experience for patients.

RECENT FINDINGS

Target-controlled infusions using propofol and other short-acting opioids for sedation have shown promising results in terms of increasing patient safety and allowing for more rapid wake-up times. Target-controlled infusion systems with real-time patient monitoring can titrate drug doses automatically to maintain optimal depth of sedation. The best recent example of this is the propofol-based Sedasys sedation system. Sedasys redefined individualized sedation by the addition of an automated clinical parameter that monitors depth of sedation. However, because of poor adoption and cost issues, it has been recently withdrawn by the manufacturer.

SUMMARY

Present automated drug delivery systems can assist in the provision of sedation for out-of-operating room procedures but cannot substitute for anesthesia providers. Use of the available technology has the potential to improve patient outcomes, decrease provider workload, and have a long-term economic impact on anesthesia care delivery outside of the operating room.

Capnography monitoring the hypoventilation during the induction of bronchoscopic sedation: A randomized controlled trial

We hypothesize that capnography could detect hypoventilation during induction of bronchoscopic sedation and starting bronchoscopy following hypoventilation, may decrease hypoxemia. Patients were randomized to: starting bronchoscopy when hypoventilation (hypopnea, two successive breaths of at least 50% reduction of the peak wave compared to baseline or apnea, no wave for 10 seconds) (Study group, n = 55), or when the Observer Assessment of Alertness and Sedation scale (OAAS) was less than 4 (Control group, n = 59). Propofol infusion was titrated to maintain stable vital signs and sedative levels. The hypoventilation during induction in the control group and the sedative outcome were recorded. The patient characteristics and procedures performed were similar. Hypoventilation was observed in 74.6% of the patients before achieving OAAS < 4 in the control group. Apnea occurred more than hypopnea (p < 0.0001). Hypoventilation preceded OAAS < 4 by 96.5 ± 88.1 seconds. In the study group, the induction time was shorter (p = 0.03) and subjects with any two events of hypoxemia during sedation, maintenance or recovery were less than the control group (1.8 vs. 18.6%, p < 0.01). Patient tolerance, wakefulness during sedation, and cooperation were similar in both groups. Significant hypoventilation occurred during the induction and start bronchoscopy following hypoventilation may decrease hypoxemia without compromising patient tolerance.

The safety and efficacy of alfentanil-based induction in bronchoscopy sedation: A randomized, double-blind, controlled trial

BACKGROUND

Alfentanil in combination with propofol produces a synergistic sedative effect in patients undergoing flexible bronchoscopy (FB). However, the use of this combination is controversial due to the risk of cardiopulmonary depression. The aim of this study was to evaluate the proper induction regimen of alfentanil in propofol target-controlled infusion for FB sedation.

METHODS

One hundred seventy-three patients were assigned randomly into 5 regimens: Group 1 and 2, alfentanil 2.5 and 5 μg/kg, respectively, immediately before propofol administration; Group 3 and 4, alfentanil 2.5 and 5 μg/kg, respectively, 2 minutes before propofol administration; and Group 5, propofol administration alone to achieve the observer assessment of alertness and sedation scale 3∼2. The bronchoscopists, physicians in charge of sedation, and patients were blind to the regimens. Adverse events, drug dose, induction, procedure and recovery time, cough severity, and propofol injection related pain were recorded.

RESULTS

The patients in groups 2 and 4 required a lower dose of propofol (P = 0.031 and 0.019, respectively) and shorter time (P = 0.035 and 0.010) than group 5 for induction. Patients in group 2 experienced more hypoxemia than those in group 5 during induction (P = 0.031). The physician in charge of sedation scored a lower severity of cough in the patients in group 4 than in groups 3 and 5. There were no differences in terms of propofol injection related pain among the groups.

CONCLUSION

Alfentanil 5 μg/kg given immediately before propofol infusion cannot be recommended. Further study is required to define conclusions about alfentanil 2.5 and 5 μg/kg because of the low power rating of subgroup in the present study.

Bronchoscopic debulking for endobronchial malignancy: Predictors of recanalization and recurrence

Background

Central airway obstruction related to endobronchial malignancy is one of the most difficult oncological complications and requires efficient palliative intervention.

Methods

Fifty-three consecutive patients with unresectable endobronchial malignancy receiving bronchoscopic cryotherapy as palliative treatment were retrospectively reviewed. Efficiency was evaluated by the improvement of performance status (PS), and the best achievement of tumor removal was assessed as complete or partial removal.

Result

Patients’ PS after cryotherapeutic tumor removal improved from the baseline PS (P = 0.006). In multivariate logistic regression analysis, the compression part of the tumor (odds ratio [OR] 0.42; 95% confidence interval [CI] 0.23∼0.75, P = 0.004) and the thin tumor stalk (OR 87.86; 95% CI 2.31∼3337.37, P = 0.016) were independent predictors of complete tumor removal. Tumors larger than 9.3 cm, including compression and invasion parts, had the highest odds of being only partially removed (positive predictive value [PPV]: 88.2%, likelihood ratio [LR]+: 10.49); tumors smaller than 9.3 cm were likely to be completely removed (negative predictive value [NPV]: 80.6%, LR−: 0.34). After cryotherapy, re-obstruction was significantly associated with non-squamous cell carcinoma (65.7 vs. 16.7%, P = 0.001) and patients who had longer overall survival (11.7 vs. 1.5 months, P < 0.001). Odds of tumor re-obstruction increased 2.28-fold (PPV: 81.6%, LR+: 2.28) beyond two months; the odds decreased by 81% (NPV: 73.3%, LR−: 0.19) within two months.

Conclusion

Debulking of a tumor using cryotherapy is a useful palliative treatment for endobronchial obstruction secondary to a variety of malignancies.

Management of anesthetic emergencies and complications outside the operating room

PURPOSE OF REVIEW

Anesthesia outside the operating room is commonly uncomfortable and risky. In this setting, anesthetic emergencies or complications may occur. This review aims to report the most recent updates regarding the management of prehospital anesthesia, anesthesia in the trauma and emergency rooms, and anesthesia for endoscopy and interventional radiology.

RECENT FINDINGS

After tracheal intubation failure, airway control of outpatients could be achieved by pharmacologically assisted laryngeal mask insertion. Management of traumatic injured patients is best guided in the frame of checklists. Monitoring sedation in this setting is challenging notably because of the threat of haemodynamic instability. Unfortunately, BIS monitoring cannot be recommended to guide sedation in this setting. Ketamine can be used to prevent hypotension during prehospital anesthesia or procedural sedation, especially as its neuroprotective effects have been recently best understood. Target-controlled infusion propofol administration with small concentration increments is adapted to prevent hypotension and hypoxaemia during sedation for gastrointestinal endoscopy and interventional radiology. Target-controlled infusion remifentanil administration is also adapted to many procedures.

SUMMARY

Anesthesia outside the operating room requires careful monitoring to avoid side-effects and education of nonanaesthetists when they are involved. A useful tool is to continuously improve the protocols and checklists to make anesthesia in this setting safer.