Tae-Yun Sung

Dreaming in sedation during spinal anesthesia: a comparison of propofol and midazolam infusion.

BACKGROUND: Although sedation is often performed during spinal anesthesia, the details of intraoperative dreaming have not been reported. We designed this prospective study to compare 2 different IV sedation protocols (propofol and midazolam infusion) with respect to dreaming during sedation. METHODS: Two hundred twenty adult patients were randomly assigned to 2 groups and received IV infusion of propofol or midazolam for deep sedation during spinal anesthesia. Patients were interviewed on emergence and 30 minutes later to determine the incidence, content, and nature of their dreams. Postoperatively, patient satisfaction with the sedation was also evaluated. RESULTS: Two hundred fifteen patients (108 and 107 in the propofol and midazolam groups, respectively) were included in the final analysis. The proportion of dreamers was 39.8% (43/108) in the propofol group and 12.1% (13/107) in the midazolam group (odds ratio = 4.78; 95% confidence interval: 2.38 to 9.60). Dreams of the patients receiving propofol were more memorable and visually vivid than were those of the patients receiving midazolam infusion. The majority of dreams (36 of 56 dreamers, 64.3%) were simple, pleasant ruminations about everyday life. A similarly high level of satisfaction with the sedation was observed in both groups. CONCLUSIONS: In cases of spinal anesthesia with deep sedation, dreaming was almost 5 times more common in patients receiving propofol infusion than in those receiving midazolam, although this did not influence satisfaction with the sedation. Thus, one does not need to consider intraoperative dreaming when choosing propofol or midazolam as a sedative drug in patients undergoing spinal anesthesia.

Clinical effects of intrathecal fentanyl on shoulder tip pain in laparoscopic total extraperitoneal inguinal hernia repair under spinal anaesthesia: A double-blind, prospective, randomized controlled trial

Objective The study evaluated the clinical intraoperative effects of intrathecal administration of fentanyl on shoulder tip pain in patients undergoing laparoscopic total extraperitoneal inguinal hernia repair (TEP) under spinal anaesthesia. Methods Patients undergoing TEP were allocated in a double-blinded, prospective, randomized manner to two groups. Spinal anaesthesia was induced by intrathecal administration of 2.8 ml of 0.5% hyperbaric bupivacaine (14 mg) in the control group and with 2.6 ml of 0.5% hyperbaric bupivacaine (13 mg) and 10 µg fentanyl (0.2 ml) in the experimental group. Results The quality of muscle relaxation, adequacy of operative space and incidence of pneumoperitoneum were similar in the two groups (n = 36 per group). Compared with the control group, the experimental group had significantly fewer cases of hypotension (12 [33.3%]) versus 23 [63.9%]) and shoulder tip pain (nine [25%] versus 18 [50%]). Intraoperative shoulder tip pain was more severe in the control group than in the experimental group. Conclusions Addition of intrathecal fentanyl to local anaesthetic can relieve shoulder tip pain with no change in complications, especially hypotension, during TEP under spinal anaesthesia.

Cerebral blood flow change during volatile induction in large-dose sevoflurane versus intravenous propofol induction: transcranial Doppler study

Background The impact of volatile induction using large-dose sevoflurane (VI-S) on cerebral blood flow has not been well investigated. The present study compared the changes in cerebral blood flow of middle cerebral artery using transcranial Doppler (TCD) during VI-S and conventional induction using propofol. Methods Patients undergoing elective lumbar discectomy were randomly allocated to receive either sevoflurane (8%, Group VI-S, n = 11) or target-controlled infusion of propofol (effect site concentration, 3.0 µg/ml; Group P, n = 11) for induction of anesthesia. The following data were recorded before and at 1, 2, and 3 min after commencement of anesthetic induction (T0, T1, T2, and T3, respectively): mean velocity of the middle cerebral artery (VMCA) by TCD, mean blood pressure (MBP), heart rate, bispectral index score (BIS) and end-tidal CO2 (ETCO2). Changes in VMCA and MBP from their values at T0 (ΔVMCA and ΔMBP) at T1, T2, and T3 were also determined. Results BISs at T1, T2 and T3 were significantly less than that at T0 in both groups (P < 0.05). ΔVMCA in Group VI-S at T2 and T3 (18.1% and 12.4%, respectively) were significantly greater than those in Group P (-7.6% and -19.8%, P = 0.006 and P < 0.001, respectively), whereas ETCO2 and ΔMBP showed no significant intergroup difference. Conclusions VI-S using large-dose sevoflurane increases cerebral blood flow resulting in luxury cerebral flow-metabolism mismatch, while conventional propofol induction maintains cerebral flow-metabolism coupling. This mismatch in VI-S may have to be considered in clinical application of VI-S.

Laparoscopic appendectomy under spinal anesthesia with dexmedetomidine infusion

Background Laparoscopic appendectomy (LA) is rarely performed under regional anesthesia because of pneumoperitoneum-related problems. We expected that dexmedetomidine would compensate for the problems arising from spinal anesthesia alone. Thus, we performed a feasibility study of spinal anesthesia with intravenous dexmedetomidine infusion. Methods Twenty-six patients undergoing LA received spinal anesthesia with intravenous dexmedetomidine infusion. During surgery, the patients pain or discomfort was controlled by supplemental fentanyl or ketamine injection, and all adverse effects were evaluated. Results No patient required conversion to general anesthesia, and all operations were completed laparoscopically without conversion to open surgery. Seventeen (65.4%) patients required supplemental injection of fentanyl or ketamine. Bradycardia occurred in seven (26.9%) patients. Conclusions Spinal anesthesia with dexmedetomidine infusion may be feasible for LA. However, additional analgesia, sedation, and careful attention to the potential development of bradycardia are needed for a successful anesthetic outcome.

Placing a Saline Bag Underneath the Heart Enhances Transgastric Transesophageal Echocardiographic Imaging During Cardiac Displacement for Off-Pump Coronary Artery Bypass Surgery

OBJECTIVE The authors hypothesized that placing a saline bag (saline-filled surgical glove) underneath a displaced heart would improve ultrasound transmission for transgastric (TG) imaging and transesophageal echocardiography (TEE) to visualize left ventricular regional wall motion (LV-RWM) during cardiac displacement for off-pump coronary artery bypass (OPCAB) surgery. DESIGN Prospective observational study. SETTING Tertiary University Hospital. PARTICIPANTS Adult patients undergoing OPCAB surgery. INTERVENTIONS Intraoperative TEE examination MEASUREMENT AND MAIN RESULTS For off-line analyses of LV-readable segments, mid-esophageal (ME, 4-chamber, 2-chamber, and long-axis) and TG (basal- and mid-short-axis) TEE views were recorded under 3 different intraoperative conditions in 13 cases of OPCAB surgery: Before cardiac displacement (Tcontrol), after cardiac displacement (Tdisplaced), and after placing the saline bag underneath the displaced heart (Tsaline-bag). There were more LV-readable segments in the 17-segment model using integrated ME and TG views(ME + TG views) at Tsaline-bag and Tcontrol (mean[95% confidence interval], 17[17-17] and 17[17-17]) than using ME+TG at Tdisplaced (15[15-16], P = 0.002 and P<0.001, respectively). Using ME + TG views provided more LV-readable segments in the 17-segment model than using ME views at Tsaline-bag (vs. 16[14-16], P < 0.001), but not at Tdisplaced (vs. 15[14-15]). Incidences of inadequate RWM monitoring (LV-readable segments<14/17 using ME + TG views) at Tsaline-bag and Tcontrol (all 0/13) were less frequent than at Tdisplaced (3/13, all P = 0.038). There were more LV-readable segments in TG basal- and mid-short-axis views at Tsaline-bag (median [range], 6[5-6] and 5[5-6]) than at Tdisplaced (0[0-2] and 0[0-1], all P < 0.05). CONCLUSIONS Placing a saline bag underneath the displaced heart enhances the ability of TEE to visualize global LV-RWM by improving TG TEE imaging during OPCAB surgery.

Factors that affect the onset of action of non-depolarizing neuromuscular blocking agents

Neuromuscular blockade plays an important role in the safe management of patient airways, surgical field improvement, and respiratory care. Rapid-sequence induction of anesthesia is indispensable to emergency surgery and obstetric anesthesia, and its purpose is to obtain a stable airway, adequate depth of anesthesia, and appropriate respiration within a short period of time without causing irritation or damage to the patient. There has been a continued search for new neuromuscular blocking drugs (NMBDs) with a rapid onset of action. Factors that affect the onset time include the potency of the NMBDs, the rate of NMBDs reaching the effect site, the onset time by dose control, metabolism and elimination of NMBDs, buffered diffusion to the effect site, nicotinic acetylcholine receptor subunit affinity, drugs that affect acetylcholine (ACh) production and release at the neuromuscular junction, drugs that inhibit plasma cholinesterase, presynaptic receptors responsible for ACh release at the neuromuscular junction, anesthetics or drugs that affect muscle contractility, site and methods for monitoring neuromuscular function, individual variability, and coexisting disease. NMBDs with rapid onset without major adverse events are expected in the next few years, and the development of lower potency NMBDs will continue. Anesthesiologists should be aware of the use of NMBDs in the management of anesthesia. The choice of NMBD and determination of the appropriate dosage to modulate neuromuscular blockade characteristics such as onset time and duration of neuromuscular blockade should be considered along with factors that affect the effects of the NMBDs. In this review, we discuss the factors that affect the onset time of NMBDs.

Anesthesia in a child with adrenoleukodystrophy

X-linked adrenoleukodystrophy (ALD) is rare genetic disorder, and children with ALD are at an increased risk of anesthetic mortality and morbidity [1]. Therefore, they require an individual anesthetic protocol based on their clinical condition. Herein we report the case of a male with childhood-onset X-linked ALD who required general anesthesia for a dental operation. An 11-year-old male (height 143 cm, weight 30 kg) was scheduled for scaling and multiple deciduous tooth extractions under general anesthesia due to his failure to cooperate willingly. He had been diagnosed with childhood-onset X-linked ALD 3 years previously. Other history included an episode of status epilepticus, adrenal insufficiency, aspiration pneumonia, pressure sores and blindness. He was bed-ridden and maintained on a positive-pressure home ventilator via tracheostomy. Physical examination revealed spastic tetraparesis, unresponsiveness to the environment, and cushingoid facies due to chronic steroid supplementation. Preoperative medications including topiramate, divalproex, prednisolone were continued until the morning of the operation. On arrival at the operating room, standard monitoring commenced. For anesthetic induction, 75 mg of pentothal sodium were injected. Anesthesia was maintained using N2O at 2 L/min, O2 at 2 L/min, and sevoflurane. About 5 min after the start of maintenance inhalational anesthesia, the surgeon was unable to open the patient’s mouth so rocuronium 10 mg was injected, after which the mouth could be opened and the surgery commenced. The operation lasted 30 min and was uneventful. Residual neuromuscular blockade was reversed with pyridostigmine 10 mg and glycopyrrolate 0.2 mg, and 15 min after administration of reversal agents, we placed the patient’s home ventilator in pressure-support ventilation (PSV) mode, as it was preoperatively. The patient was observed closely for over 1 h by an anesthesiologist and a pediatrician in the post-anesthesia care unit (PACU). The home ventilator with PSV mode was well tolerated, so we then transferred the patient to the general ward under monitoring with pulse oximetry. X-linked ALD is a progressive neurodegenerative disorder characterized by demyelination of cerebral white matter, axonopathy of the spinal cord, and reduced adrenal response to adrenocorticotropic hormone. The onset age of the condition is between 3 and 10 years, and the patients initially present with behavioral problems and deficits in memory and language. As the disease progresses, vision loss, auditory impairment, hemiparesis and spastic tetraparesis may occur. In the later stages, seizures begin and the patient becomes bedridden, blind, and unable to interact with the environment. Death usually ensues within 2 to 4 years after the onset of symptoms [1]. There are several considerations in anesthetic management for these patients. The anesthetic plan should be formulated based on each individual patient’s condition according to their disease progression. In our case, the anesthetic plan focused on the prevention of seizures and early return to the preoperative condition without any anesthesia-related complications. In an ALD patient with seizure disorders, anticonvulsants should be continued throughout the perioperative period, including the day of surgery, and the anesthesiologist should consider the altered pharmacokinetics of anesthetics due to hepatic microsomal enzyme induction secondary to chronic antiseizure

Endotracheal intubation-related vocal cord ulcer following general anesthesia

Post-intubation throat pain is a common complaint that is caused by focal ischemia, damage to the laryngeal mucosa, or edema. However, if the laryngeal symptoms persist after 72 h, vocal cord paralysis, the formation of granulation tissue, or ulcers can occur [1]. Most vocal cord ulcers that are caused by intubation are found after progression to granuloma. However, we recently observed a patient in whom the ulcer was detected before progression, and was successfully treated with conservative interventions. A 39-year-old male (167 cm, 66 kg) was scheduled for elective Guyons tunnel release surgery. The patient had no significant medical history, except for septoplasty surgery 6 years ago using general anesthesia with endotracheal intubation. Pre-operatively, he exhibited no laryngopharyngeal symptoms such as sore throat, hoarseness, or stridor. Anesthesia was induced using 130 mg propofol, and endotracheal intubation was performed with 35 mg rocuronium. An endotracheal tube with an internal diameter of 8.0 mm, and a high volume/low pressure cuff was used. Laryngoscopy was performed using a standard 3 Macintosh metal blade, a stylet, and external laryngeal pressure, and was characterized as Cormack-Lehane laryngoscopy grade III. There was slight friction when going through the vocal cord during intubation, but the process was otherwise successful. The duration of intubation was 65 min, and anesthesia was completed without any specific hemodynamic instability. Emergence was smooth, and extubation was completed without any coughing or vigorous movement. After surgery, the patient persistently complained of throat pain during the hospitalization period. However, the attending physician and nurse overlooked his complaints because throat pain was considered to be a normal side effect of intubation. He was therefore discharged 4 days after the operation without any further examination. The day after discharge, the patient was concerned that his sore throat persisted, unlike his previous experience with general anesthesia and intubation, and visited an otolaryngology outpatient clinic. Laryngeal endoscopic examination showed an ulcer in the posterior of the vocal cord (Fig. 1A). Prednisolone (5 mg, BID) and esomeprazole (40 mg, QD) were prescribed, and voice rest was recommended. His sore throat improved after 1 week, and laryngoscope examination revealed partial cure of the vocal cord ulcer (Fig. 1B). After subsequent visits, the ulcer had completely healed without progressing to granuloma. Fig. 1 (A) Five days after surgery, a vocal cord ulcer was observed in the rightsided posterior of the vocal cord. (B) Twelve days after surgery, the vocal cord ulcer had decreased in size after medical therapy and voice rest. Vocal cord ulcers are non-neoplastic lesions of the posterior glottis, and represent an early stage in the progression of vocal cord granulomas [2]. Generally, vocal cord ulcers occur due to mechanical or chemical damage, such as the overuse of voice, chronic coughing, throat clearing, or gastroesophageal reflux disease [3]. The common symptoms of vocal cord ulcers and granulomas are throat pain, hoarseness, and coughing [4]. The causes of vocal cord ulcers related to endotracheal intubation are vocal cord mucosa damage during intubation and extubation, clasping movements between the vocal cords and the tube, continuous pressure of the tube during anesthesia, use of a tube that is too large, or infection. During endotracheal intubation, inflammation can occur on the mucous membrane of the vocal process area of arytenoid cartilage, and its severity tends to increase with longer intubation times or increased pressure [5]. In the current case, the duration of intubation was short, and there was little or no movement of the head and neck during the surgery or extubation. It is therefore likely that the vocal cord ulcer was caused by friction with the tube during intubation, damaging the vocal cord mucosa. It is also possible that the endotracheal tube used was too large, or that the pressure exerted by the external cricoids led to backward and lateral tilt, making the vocal process more prominent and vulnerable to injury [5]. Most vocal cord ulcers can be cured with conservative treatment such as voice therapy, or medical interventions including steroids, antibiotics, proton pump inhibitors, or histamine-2 receptor blockers. However, if the cause of ulcer is iatrogenic or the ulcer has progressed to granuloma, it may lead to aspiration and respiratory distress, and so long-term treatment or even surgical excision may be required [1,4]. To prevent post-intubation vocal cord ulcers from occurring, using an appropriately sized tube, adequate sedation and muscle relaxation, performing smooth intubation, stabilization of the tube, and extubation without laryngeal reflexes are recommended [4,5]. In conclusion, anesthesiologists should recognize that vocal cord ulcers could occur as a complication of intubation following endotracheal anesthesia. Persistent post-operative laryngopharyngeal symptoms should not be overlooked, and appropriate examinations will help identify complications, such as ulcers, before they progress to granuloma.

Does Near-Infrared Spectroscopy Provide an Early Warning of Low Haematocrit following the Initiation of Hypothermic Cardiopulmonary Bypass in Cardiac Surgery?

This study investigated 151 patients undergoing cardiac surgery to determine whether measurement of regional cerebral oxygen saturation (rScO2) using near-infrared spectroscopy (NIRS) can indicate a low haematocrit after initiation of hypothermic cardiopulmonary bypass (CPB). Haematocrit, rScO2, haemoglobin level, arterial partial pressures of carbon dioxide and oxygen, systemic blood pressure, and nasopharyngeal and rectal temperatures were determined 5 min after the initial administration of heparin for CPB and 90 s after completion of the first cardioplegic solution injection. Immediately after initiation of hypothermic CPB, rScO2, haemoglobin and haematocrit values were significantly lower than those before CPB. No significant correlations were found between the change in haematocrit and changes in left, right and mean rScO2; thus, changes in rScO2 before and after initiation of hypothermic CPB did not reflect changes in haematocrit values. This indicates that NIRS cannot provide early warning of a low haematocrit immediately after initiation of hypothermic CPB in cardiac surgery.

Abrupt formation and spontaneous resolution of a right atrial thrombus detected by intraoperative transesophageal echocardiography during replacement of an abdominal aortic aneurysm

Intraoperative formation of a thrombus in the right atrium and its management has occasionally been reported. However, spontaneous resolution of right atrial thrombi, without any event, is rare. We report a case of abrupt right atrial thrombus formation and spontaneous resolution, with no events, detected by transesophageal echocardiography during the replacement of an abdominal aortic aneurysm.