The Use of Conscious Sedation for Outpatient Dermatologic Surgical Procedures

BACKGROUND: Dermatologic surgery has undergone increasing levels of sophistication over the past few decades. Commensurate with this demand, an established anesthesia technique called conscious sedation has been employed. OBJECTIVES: Methods for performing office-based conscious sedation are described. Recommendations are made regarding prerequisites for conscious sedation in an office setting, patient selection, complications management, and postoperative discharge requirements. CONCLUSION: The goals of anesthesia are to provide for patient safety and comfort, to increase patient acceptance of the procedure, and to enhance the surgeon's efficiency and satisfaction.     

The Combined Use of Propofol and Fentanyl for Outpatient Intravenous Conscious Sedation

BACKGROUND: Intravenous conscious sedation is currently being widely utilized for outpatient surgery including dermatologic surgery. Even though this type of anesthesia is typically administered by a trained, licensed anesthetist, it is important for dermatologists who either intend to or are currently utilizing this type of anesthesia to be familiar with some of the methods and agents that are commonly employed. OBJECTIVE: Propofol and fentanyl are two anesthetic agents that are in prevalent use for skin and soft tissue surgery of brief or limited duration. With the goal of familiarizing dermatologic surgeons with this form of anesthesia, a study was conducted to evaluate the safety and effectiveness of the combination of propofol and fentanyl when used for conscious sedation in an outpatient dermatology center. METHODS: Twenty patients, ages 25-65 years, who required conscious sedation were enrolled. Each patient received a standard dosage of fentanyl and propofol, as determined on a kilogram basis. Sedation time, total procedure time, recovery time, and total propofol dose, along with side effects, were determined. RESULTS: The mean onset to sedation was 52.5 seconds, the mean procedure time was 40 minutes 37 seconds, and the mean interval to recovery was 3 minutes 43 seconds, with a mean total dose of propofol of 5.83 mg/kg. Minimal side effects occurred. CONCLUSION: Propofol when used in conjunction with fentanyl appears to be a safe, quick, and effective method of providing conscious sedation.     

右美托咪定复合舒芬太尼清醒镇静在脂肪抽吸术中的应用

目的探讨右美托咪定复合舒芬太尼应用于脂肪抽吸术中清醒镇静的有效性和安全性。方法自2018年1月至2018年6月,共40例行脂肪抽吸术的女性患者入选(ASAⅠ～Ⅱ级)。镇静诱导予以右美托咪定1μg/Kg作为负荷量,时间10 min,然后持续输注右美托咪定每小时0.4μg/Kg。肿胀液注射前静注舒芬太尼0.2μg/Kg,术中手术刺激患者有体动时,追加舒芬太尼5～10μg。术毕前5～10 min停止药物输注。分别记录镇静前、静注右美托咪定15、30和60 min以及术毕时的血流动力学和呼吸的变化,Ramsay镇静分级。观察有无低氧血症、呼吸暂停、心动过缓等并发症。记录总麻醉时间和各药物用量。结果 40例患者均获得满意的镇静效果,Ramsay镇静分级2～4级。镇静后各时间点的患者心率均低于镇静前(P<0.05)。与镇静前相比,镇静后15 min收缩压、舒张压下降明显(P<0.05),而镇静后其他时间点的收缩压、舒张压与镇静前相比无明显统计学差异(P>0.05)。镇静后的呼吸、SpO2无明显下降(P>0.05)。术中有2例患者出现不同程度呼吸抑制,2例患者出现窦性心动过缓,无严重不良反应发生。麻醉时间为(168±58) min,右美托咪定、舒芬太尼的用量分别为(126±36)μg和(15±5)μg。结论右美托咪定复合舒芬太尼可安全应用于脂肪抽吸术中的清醒镇静。     

异丙酚清醒镇静术用于阻生齿拔除的临床观察

目的：观察异丙酚与局麻合用在阻生齿拔除术中的镇静、遗忘作用并与加用氯铵酮对比。：门诊成人阻生齿拔除４０例,随机分为异丙酚组（Ｐ组,ｎ＝２５）和异丙酚加氯胺酮组（ＰＫ组,ｎ＝１５）。首次量分别静注异丙酚０．８￣１．２ｍｇ／ｋｇ和异丙酚０．６ｍｇ／ｋｇ加氯胺酮０．２ｍｇ／ｋｇ,此后持续静注异丙酚,以维持镇静３级为度,２％利多卡因行齿槽神经阻滞。结果：术中两组均维持镇静３级。术后ＶＡＳ为０。Ｐ组和ＰＫ组     

Duplex Ultrasonography Has Limited Utility in Detection of Postoperative DVT After Primary Total Joint Arthroplasty

Background

Duplex ultrasound is routinely used to evaluate suspected deep venous thrombosis after total joint arthroplasty. When there is a clinical suspicion for a pulmonary embolism, a chest angiogram (chest CTA) is concomitantly obtained.

Questions/Purposes

Two questions were addressed: First, for the population of patients who receive duplex ultrasound after total joint arthroplasty, what is the rate of positive results? Second, for these patients, how many of these also undergo chest CTA for clinical suspicion of pulmonary embolus and how many of these tests are positive? Furthermore, what is the correlation between duplex ultrasound results and chest CTA results?

Methods

A retrospective chart review was conducted of total joint replacement patients in 2011 at a single institution. Inclusion criteria were adult patients who underwent a postoperative duplex ultrasonography for clinical suspicion of deep venous thrombosis (DVT). Demographic data, result of duplex scan, clinical indications for obtaining the duplex scan, and DVT prophylaxis used were recorded. Additionally, if a chest CTA was obtained for clinical suspicion for pulmonary embolus, results and clinical indication for obtaining the test were recorded. The rate of positive results for duplex ultrasonography and chest CTA was computed and correlated based on clinical indications.

Results

Two hundred ninety-five patients underwent duplex ultrasonography of which only 0.7% were positive for a DVT. One hundred three patients underwent a chest CTA for clinical suspicion of a pulmonary embolism (PE) of which 26 revealed a pulmonary embolus, none of which had a positive duplex ultrasound.

Conclusion

Postoperative duplex scans have a low rate of positive results. A substantial number of patients with negative duplex results subsequently underwent chest CTA for clinical suspicion for which a pulmonary embolus was found, presumably resulting from a DVT despite negative duplex ultrasound result. A negative duplex ultrasonography should not rule out the presence of a DVT which can embolize to the lungs and thus should not preclude further workup when clinical suspicion exists for a pulmonary embolus.

     

Dexmedetomidine Sedation With and Without Midazolam for Third Molar Surgery

Twenty-four patients were randomly divided into 2 groups. Intraoperatively, one group received a continuous intravenous infusion of dexmedetomidine alone, whereas the other received a continuous dexmedetomidine infusion plus a small dose of midazolam. Early measurements of patient anxiety and psychomotor performance were lower in patients who had received midazolam. This difference was not seen later in the appointment. An amnesic effect was observed in those patients who received midazolam. This effect, however, did not translate into increased patient satisfaction in the group receiving midazolam. Our findings suggest a prolonged discharge time for patients who had been given midazolam that may be clinically significant. Overall, dexmedetomidine showed an unpredictable sedative response and may be less practical than more common alternatives for oral surgery procedures.Key Words: Dexmedetomidine, Anesthesiology, Oral surgery, Sedation, Third molarsAlpha-2 (α-2) adrenergic receptor agonists were first used as nasal decongestants but soon were valued for the treatment of hypertension and withdrawal symptoms. The sedative and amnesic qualities of clonidine, the prototypic representative of this drug class, fueled interest in its use as an anesthetic adjuvant. It was also quickly noted that, at sedative doses, the normal respiratory drive was unaffected when administered as an intravenous infusion.^1–3 Dexmedetomidine (Precedex, Abbott Laboratories), the pharmacologically active dextroisomer of medetomidine, like clonidine, has an imidazoline structure and is a potent and selective agonist of the α-2 adrenoceptor. Compared with clonidine, dexmedetomidine shows 8 times greater selectivity for α-2 than α-1 receptors and is considered a full agonist. It has been used in veterinary anesthesiology for more than 20 years and has demonstrated dose-dependent sympatholytic, sedative, and analgesic properties in human volunteers.^4–6 Dexmedetomidine, when administered in the perioperative period, has been shown to reduce the dose requirements of other anesthetics and attenuate the sympathetic response to stressful events.^7–10Alpha-2 adrenergic receptors are G-protein–coupled receptors.^11–13 Presynaptic α-2 receptors are found in sympathetic nerve endings and noradrenergic neurons of the central nervous system (CNS), where their primary function is to inhibit release of norepinephrine. Postsynaptic α-2 receptors exist in various tissues, including the liver, pancreas, kidney, adipose tissue, eye, and vascular smooth muscle, where they play a complex physiologic role.¹⁴ A high density of α-2 receptors exists in the locus ceruleus, a small brain stem structure that is important in modulating vigilance. Evidence exists that suggests that the locus ceruleus is part of an endogenous sleep-promoting pathway.¹⁵ These neurons have inhibitory control over γ-aminobutyric acid (GABA)–containing neurons in the ventrolateral preoptic nucleus of the anterior hypothalamus and, in turn, affect the higher centers in the brain associated with loss of wakefulness. The clinical sedative response of α-2 adrenergic agonists is similar to natural sleep, where patients remain easily arousable and able to follow commands after minimal stimulation.^2,16,17Midazolam is a benzodiazepine that exerts its pharmacologic effect by facilitating GABA, the major inhibitory neurotransmitter of the CNS. The subsequent enhanced opening of chloride channels leads to hyperpolarization of the neuron and resistance to stimulation.¹⁸ Clinically, the anesthetic properties of midazolam include anxiolysis, sedation, and amnesia. In rats, a synergistic interaction has been observed for multiple measures of CNS depression when a combination of dexmedetomidine and midazolam is administered.^19,20Dexmedetomidine, with a context-sensitive half-life similar to that of fentanyl, found initial use in the short-term (<24 hours) sedation of postoperative patients requiring ventilation in the intensive care unit.²¹ The average protein binding of an intravenously administered dose is 94%, with distribution and elimination half-lives of 6 minutes and 2 hours, respectively. It is extensively biotransformed in the liver and, with metabolites, excreted primarily in the urine. A potential adverse reaction to intravenously administered dexmedetomidine is a peripherally mediated, postsynaptic α-2 receptor–activated hypertension, particularly when it is administered as an intravenous bolus rather than as an infusion.^21,22 This reaction is most commonly seen in the early phase of administration. Conversely, attenuation of sympathetic outflow from the CNS may result in unacceptable hypotension and bradycardia. Interestingly, it appears that baroreflex sensitivity is not changed and patients will have appropriate heart rate responses to hypotension and hypovolemia.^1,23At present there appear to be at least 3 major receptor subtypes for dexmedetomidine: α2A, α2B, and α2C. While the role of these receptor subtypes continues to be explored, it has become evident that the α2A and α2C subtypes predominate in the CNS and may be responsible for the sedative, analgesic, and sympatholytic components of agonist action. The α2B receptors are more frequently located on vascular smooth muscle and appear to mediate the hypertensive effects of high doses of dexmedetomidine.^15,24–26Balanced intravenous sedation techniques are often administered during surgery to provide anxiolysis, sedation, and analgesia for the patient. These frequently include benzodiazepines, opioids, low-dose infusions of propofol, or combinations of these, titrated to achieve the desired effect. Such techniques can sometimes have the undesired effect of respiratory depression. The search continues for an ideal sedative that is safe, rapidly acting, inexpensive, and titratable and that has minimal side effects.An unpublished thesis of a pilot study comparing the sedative effects of a low-dose propofol infusion and opioid to those of dexmedetomidine for third molar extractions found that patients receiving dexmedetomidine were more aware of the procedure; for some, that was a source of anxiety.²⁷ We hypothesized that the addition of a small dose of a benzodiazepine (midazolam) to the dexmedetomidine infusion might improve the patient''s experience.     

Bispectral Analysis of the Electroencephalogram Predicts Conscious Processing of Information during Propofol Sedation and Hypnosis

Background: The bispectral index (BIS) measures changes in the interfrequency coupling of the electroencephalogram (EEG). The purposes of this study were (1) to determine whether BIS correlates with responses to command during sedation and hypnosis induced by propofol or propofol and nitrous oxide, and (2) to compare BIS to targeted and measured concentrations of propofol in predicting participants' responses to commands.

Methods: Twenty volunteers (15 men and 5 women, aged 22-50 yr) were given propofol by computer-controlled infusion, and EEG was recorded for off-line analysis of BIS. Responses to randomly ordered verbal commands or voice plus touch were measured with two categorical scales (CS1 and CS2, respectively). All subjects received a propofol infusion targeted to achieve effect site concentrations of 1, 2, 4, 2, 1, and 0 micro gram/ml. Ten participants had repeated infusion, whereas 10 others breathed 30% nitrous oxide and oxygen and received a propofol infusion targeted for 0.5, 1, 2, 4, 2, 1, 0.5, and 0 micro gram/ml. Five minutes after each targeted concentration had been reached, CS1, CS2, and arterial propofol concentration were determined. The area under the receiver operating characteristic curve was used to compare the accuracy of (1) BIS, (2) targeted propofol concentration, (3) measured concentration, and (4) treatment history as predictors of response.

Results: Bispectral index was a strong predictor of CS1 and CS2 (P < 0.0001) and significantly more accurate than targeted or measured propofol concentrations (P < 0.0003 and P < 0.003, respectively). It also provided additional predictive power when combined with treatment history (P < 0.02). Nitrous oxide slightly decreased the probability of response at a given value of BIS (P < 0.05), but accuracy was unaffected.     

舒芬太尼联合右美托咪定清醒镇静在整形外科手术中的应用效果

分析舒芬太尼联合右美托咪定清醒镇静在整形外科手术中的应用效果。方法 选取东台市新街镇卫生院2020年1月-2022年12月收治的70例整形外科手术患者,随机将其分为对照组和观察组,每组35例。对照组单用舒芬太尼,观察组采用舒芬太尼联合右美托咪定,比较两组Cor、HR、NE和MAP水平与疼痛介质水平。结果 T0时,两组Cor、HR、NE和MAP水平比较,差异无统计学意义（P ＞0.05）,T1~T3时,观察组Cor、HR、NE水平低于对照组（P ＜0.05）,MAP水平高于对照组（P ＜0.05）;术后24 h,两组血清SP、5-HT和PGE2水平均高于麻醉诱导前（P ＜0.05）,且观察组血清SP、5-HT和PGE2水平低于对照组（P ＜0.05）。结论 舒芬太尼联合右美托咪定清醒镇静在整形外科手术中具有较好的应用效果,可有效改善Cor、HR、NE和MAP水平与疼痛介质水平。     

Outpatient Total Hip Arthroplasty Has Minimal Short-Term Complications With the Use of Institutional Protocols

Background

Interest in outpatient/same-day discharge (SDD) total hip arthroplasty (THA) has been increasing over the last several years. There is considerable debate in the literature regarding the complication and readmission rates of these patients. To evaluate and validate the safety and efficacy of our institutional SDD THA care pathway, we compared the outcomes of patients undergoing SDD THA with patients who had a similar comorbidity profile and underwent inpatient THA.

经皮穴位电刺激对咪达唑仑镇静作用的影响

目的:探讨经皮穴位电刺激对咪达唑仑镇静作用的影响。方法:选择在我院择期椎管内麻醉行骨科下肢手术患者80例,随机分为两组:经皮穴位电刺激组和对照组,每组均40例。经皮穴位电刺激组在完成椎管内麻醉后开始给予经皮穴位电刺激,刺激参数频率2/100 Hz,波宽0.2~0.6 ms,调节刺激电流至患者可耐受的最大强度,穴位选择双侧合谷穴、内关穴,20 min后靶控输注咪达唑仑。对照组患者在相应穴位贴电极片,并连接刺激器,不予电刺激。对患者进行警觉/镇静(OAA/S)评分,依据脑电双频指数(BIS)调整咪达唑仑靶控输注浓度。观察并记录OAA/S评分首次为3分时的目标靶浓度(Ce)、BIS、咪达唑仑用量、平均动脉压(MAP)、血氧饱和度(SpO2)、心率(HR)及氟马西尼使用和不良反应发生情况。结果:经皮穴位电刺激组在OAA/S评分首次为3分时咪达唑仑效应室靶浓度较对照组低[(60.3±8.0)ng/mL vs.(66.8±8.5)ng/mL],经皮穴位电刺激组的咪达唑仑用量少于对照组[(4.9±0.6)mg vs.(5.3±0.5)mg],差异均有统计学意义(P<0.05);经皮穴位电刺激组术后应用氟马西尼12例,低于对照组的28例,差异有统计学意义(P<0.05);2组间BIS、SpO2、MAP、HR差异无统计学意义。结论:经皮穴位电刺激能够增强咪达唑仑的镇静作用,减少咪达唑仑用量。