Michiaki Yamakage

Effects of local infiltration analgesia for posterior knee pain after total knee arthroplasty: comparison with sciatic nerve block

BackgroundAlthough femoral nerve block provides good analgesia after total knee arthroplasty (TKA), residual posterior knee pain may decrease patient satisfaction. We compared the efficacy of periarticular infiltration analgesia (PIA) and sciatic nerve block (SNB) for posterior knee pain.MethodsForty-nine patients scheduled for TKA were prospectively randomized into the PIA group (nxa0=xa025) or SNB group (nxa0=xa024) and received general anesthesia with ultrasound-guided femoral nerve block (FNB). In the PIA group, 60xa0ml 0.5xa0% ropivacaine and 0.3xa0mg epinephrine were injected intraoperatively into the periarticular soft tissue before inserting the components. In the SNB group, patients received ultrasound-guided SNB with 20xa0ml 0.375xa0% ropivacaine and periarticular infiltration with 20xa0ml normal saline and 0.3xa0mg epinephrine. We evaluated postoperative pain scores, posterior knee pain, frequency of rescue analgesics for 36xa0h, and performance time of PIA and SNB.ResultsVisual analogue pain scores at 12–24xa0h were significantly lower in the PIA group than in the SNB group (pxa0<xa00.05). The majority of patients had no posterior knee pain. There were no significant differences between the groups in frequency and time of first administration of rescue analgesics and in side effects. Time for performance of periarticular infiltration was significantly shorter than that for SNB (pxa0<xa00.05). The dose of intraoperative remifentanil was significantly lower in the SNB group than in the PIA group (pxa0<xa00.001).ConclusionsThe combination of FNB and PIA provides sufficient analgesia after TKA. The rapid and convenient periarticular infiltration technique could be a good alternative to SNB.

Efficacy and Safety of a Lidocaine and Ropivacaine Mixture for Scalp Nerve Block and Local Infiltration Anesthesia in Patients Undergoing Awake Craniotomy.

Background: Mixtures of various local anesthetics, such as lidocaine and ropivacaine, have been widely used. However, their efficacy and safety for scalp nerve blocks and local infiltration during awake craniotomy have not been fully elucidated. Methods: We prospectively investigated 53 patients who underwent awake craniotomy. Scalp block was performed for the blockade of the supraorbital, supratrochlear, zygomaticotemporal, auriculotemporal, greater occipital, and lesser occipital nerves with a mixture containing equal volumes of 2% lidocaine and 0.75% ropivacaine, including 5 &mgr;g/mL of epinephrine. Infiltration anesthesia was applied at the site of skin incision using the same mixture. The study outcomes included changes in heart rate and blood pressure after head pinning and skin incision, and incidence of severe pain on emergence from anesthesia. Total doses and plasma concentrations of lidocaine and ropivacaine were measured at different time points after performing the block. Results: The heart rate and blood pressure after head pinning were marginally, but significantly, increased when compared with baseline values. There were no significant differences in heart rate and blood pressure before and after the skin incision. Nineteen percent of the patients (10/53) complained of incisional pain at emergence from anesthesia. The highest observed blood concentrations of lidocaine and ropivacaine were 1.9±0.9 and 1.1±0.4 &mgr;g/mL, respectively. No acute anesthetic toxicity symptom was observed. Conclusions: Scalp block with a mixture of lidocaine and ropivacaine seems to provide effective and safe anesthetic management in patients undergoing awake craniotomy.

Incidence of cannot intubate-cannot ventilate (CICV): results of a 3-year retrospective multicenter clinical study in a network of university hospitals

PurposeThe purpose of this study was to investigate the incidence of cannot intubate-cannot ventilate (CICV) during general anesthesia during a 3-year period in a network of university hospitals and to evaluate the events related to it.MethodsA retrospective multicenter questionnaire survey of CICV, based on medical record review, was conducted over a 3-year period (January 2010–December 2012) in Hokkaido, Japan. All cases were assessed in terms of the suspected risk factors of CICV, the clinical course during anesthesia, and the prognosis.ResultsResponses were obtained from 20 of 21 institutions (95xa0%) surveyed. The incidence of CICV was 3 of 97,854 cases conducted under general anesthesia (0.003xa0%). All incidents occurred during induction of general anesthesia. In two of the three cases, difficult airway was predicted preoperatively. In all these three cases, mask ventilation became impossible after repeated intubation attempts with devices such as the Macintosh laryngoscope, the Airwayscope, or a fiberoptic bronchoscope. A laryngeal mask was inserted in one case, but the lungs could not be adequately ventilated. Emergency tracheotomy was eventually performed in all the CICV cases. Although two of the patients did not have postoperative neurological sequelae, severe and permanent brain damage occurred in one patient.ConclusionIn our survey, we found that the incidence of CICV during a 3-year period (2010–2012) was 0.003xa0% or 1 in 32,000 cases. The three CICV situations occurred after repeated intubation attempts with multiple devices. The appropriate airway devices to be used in a particular difficult airway situation should be carefully considered before performing multiple attempts.

Effect of prone positioning on cannula function and impaired oxygenation during extracorporeal circulation

Prone ventilation is an effective method for improving oxygenation in patients with acute respiratory failure. However, in extracorporeal circulation, there is a risk of cannula-related complications when changing the position. In this study, we investigated cannula-related complications when changing position for prone ventilation and the effect of prone ventilation on impaired oxygenation in patients who underwent extracorporeal membrane oxygenation (ECMO). The study subjects were patients who underwent prone ventilation during ECMO in the period from 2004 to 2011. Indication for prone ventilation was the presence of dorsal infiltration shown by lung computed tomography. Factors investigated were cannula insertion site, dislodgement or obstruction of the cannula, malfunction of vascular access and unplanned dislodgement of the catheters when changing position. Mean arterial pressure, PaO2/FiO2, PEEP level, blood flow and rotation speed of the pump were also determined before and after position change. Five patients were selected as study subjects. The mean duration of prone positioning was 15.3xa0±xa00.5xa0h. Strict management during position changes prevented cannula-related complications in the patients who underwent extracorporeal circulation. There were no significant changes in mean arterial pressure, PEEP level, blood flow and rotation speed of the pump when changing position. Low PaO2/FiO2 prior to prone ventilation was significantly increased after supine to prone and then prone to supine position. Prone positioning to improve impaired oxygenation is a safe procedure and not a contraindication in patients receiving extracorporeal circulation.

Retrolaminar block: analgesic efficacy and safety evaluation

PurposeRetrolaminar block (RLB) is a thoracic truncal block that can produce analgesia for the thoracic and abdominal wall. However, the characteristics of RLB are not well known. The aim of this study was to determine analgesic efficacy by measuring postoperative consume of patient-controlled analgesia (PCA), additional nonsteroidal antiinflammatory drug (NSAID) rescue, and opioid rescue. Our secondary analysis included assessment of the chronological change in arterial levobupivacaine concentrations after the block.MethodsThis prospective, randomized, double-blinded study included 30 patients scheduled for modified radical mastectomy under general anesthesia. The patients were randomized to receive either a landmark-guided RLB or paravertebral block (PVB) catheter placement on T4. Continuous infusion with 4xa0ml/h of 0.25xa0% levobupivacaine was started for 72xa0h, after initial injection of 20xa0ml 0.375xa0% levobupivacaine before surgery. Postoperative pain was compared using the amount of block PCA (3xa0ml 0.25xa0% levobupivacaine with 30-min lockout), NSAID, and opioid rescue. Arterial blood was sampled for 120xa0min after the initial injection.ResultsThe frequency of postoperative block PCA use was significantly high after RLB in 24xa0h [pxa0=xa00.01; 6 (3–12) vs. 2.5 (0.3–3) times, respectively]. There was no PCA use after 24xa0h in either group. There was no postoperative opioid rescue use throughout the study. After RLB and PVB, there was no significant difference in Tmax (pxa0=xa00.14; 15xa0±xa08 vs. 15xa0±xa08xa0min, respectively) and Cmax (pxa0=xa00.2; 0.9xa0±xa00.2 vs. 0.9xa0±xa00.3xa0µg/ml, respectively), and all the concentrations were below the threshold of local anesthetic systemic toxicity.ConclusionContinuous RLB was not inferior to PVB except for the first 24xa0h, and was satisfactory after mastectomy. RLB showed safe, low peak arterial levobupivacaine concentrations.

Recovery of postoperative cognitive function in elderly patients after a long duration of desflurane anesthesia: a pilot study

Postoperative cognitive dysfunction (POCD) increases morbidity and mortality. The mechanisms underlying POCD remain elusive; however, systemic responses induced by anesthesia and surgery might trigger neuroinflammation and POCD. Desflurane is a preferable volatile anesthetic agent for elderly patients because it facilitates shorter recovery from general anesthesia. The aim of this study was to determine whether quality of emergence and cognitive function in elderly patients undergoing a long duration desflurane anesthesia are better than those in the case of sevoflurane anesthesia. Forty-two patients who were older than 65xa0years of age and scheduled for surgery of more than 4xa0h in duration were enrolled in this study. Patients were randomly assigned to a desflurane anesthesia group (D group) and sevoflurane anesthesia group (S group). General anesthesia was maintained with 3.5xa0% desflurane (D group) and 1.0xa0% sevoflurane (S group). The Mini-Mental State Examination (MMSE) was used for assessing cognitive function 24xa0h before and after surgery. Postoperative MMSE score in the D group was significantly improved compared to that in the preoperative period. In conclusion, elderly patients undergoing desflurane anesthesia have significantly better quality of emergence and may have better cognitive function than those in elderly patients undergoing sevoflurane anesthesia.

Evaluation of bias in predicted and measured propofol concentrations during target-controlled infusions in obese Japanese patients: an open-label comparative study.

BACKGROUND Target-controlled infusions (TCIs) of propofol are commonly used for general anaesthesia. The Marsh model pharmacokinetic parameter set incorporated in TCI devices for propofol could increase bias when used in obese patients. OBJECTIVE The purpose of this study was to assess the optimal predicted blood concentration (Cp) of 4.0u200a&mgr;gu200aml−1 of propofol using a correction formula including BMI and to evaluate the influences on propofol concentration in obese patients. DESIGN An open-label, comparative study. SETTING Sapporo Medical University Hospital, Japan, from October 2011 to December 2013. PATIENTS Seventy-five adults scheduled for elective surgery under general anaesthesia with the following exclusion criteria: less than 30 or more than 65 years of age; American Society of Anesthesiologists status 3 to 5; allergy to propofol; the daily use of psychoactive drugs; known or suspected drug or alcohol abuse; and cardiac, hepatic, renal or neurological impairment. INTERVENTION Propofol was administered and maintained at a Cp of 4.0u200a&mgr;gu200aml−1 using a TCI device programmed with the Marsh pharmacokinetic model. Arterial blood samples were collected at 15, 30, 60, 90, 120, 150 and 180u200amin after the start of the infusion, and the measured propofol concentration (Cm) was determined. After calculation of the adjustment formula using the corrected Cp of 69 patients, we then applied the corrected Cp to five other obese patients. MAIN OUTCOME MEASURES The median performance error (MDPE) and median absolute performance error (MDAPE) were calculated to measure bias at each time point. RESULTS We analysed 333 samples from the 69 individuals. There was a significant correlation between BMI and Cm, which tended be greater than 4.0u200a&mgr;gu200aml−1 in obese patients. Our new method improved MDPE and MDAPE from a range of 20 to 40 for both, to ranges of −11.3 to −1.8 and 8.8 to 11.5, respectively. CONCLUSION BMI influences blood propofol concentrations, leading to the possibility of overdosage of propofol in obese patients when the Marsh model is used to assess propofol concentration. Our new method using corrected Cp might improve this bias in obese, Japanese patients.

Chronological Changes in Ropivacaine Concentration and Analgesic Effects Between Transversus Abdominis Plane Block and Rectus Sheath Block.

Background and Objectives Transversus abdominis plane block (TAPB) and rectus sheath block (RSB) are popular methods of controlling postoperative pain. Chronological changes in blood concentrations of local anesthetics have not been described, although a large amount of local anesthetic is required to block these compartments. We postulated that blood concentrations of anesthetics would peak earlier during TAPB than RSB (primary end point). Secondary end points were elapsed time from block until first postoperative rescue analgesia and affected dermatomes. Methods This prospective, randomized study included 22 patients scheduled for laparoscopic ovarian surgery under general anesthesia. The patients were randomized to receive either a bilateral single-shot TAPB or a bilateral RSB (15 mL of 0.5% ropivacaine per side). Arterial blood was sampled 10, 20, 30, 45, 60, 90, and 120 minutes after ropivacaine administration. This trial was registered at the UMIN-Clinical Trials Registry (UMIN000012133) before patient recruitment. Results Arterial ropivacaine levels after block peaked earlier in the TAPB than in RSB [Tmax: 35 (12) vs 53 (16) minutes; P = 0.02], whereas peak ropivacaine concentrations did not significantly differ between the groups [Cmax: 1.83 (0.41) vs 1.79 (0.33) &mgr;g/mL; P = 0.54]. Peak ropivacaine concentrations exceeded 2.2 &mgr;g/mL in 1 and 2 patients in the RSB and TAPB groups, respectively, although symptoms of local anesthetic systemic toxicity were not evident in any of them. The median [interquartile range] duration of analgesia was significantly longer for TAPB than RSB (421 [335–536] vs 196 [168–277] minutes; P = 0.01). Conclusions Peak ropivacaine concentrations were comparable during TAPB and RSB, but peaked earlier during TAPB. Although 150 mg of ropivacaine remained effective significantly longer during TAPB than RSB during laparoscopic surgery, this dose could cause local anesthetic systemic toxicity. The analgesic effects of blocks with less ropivacaine should be assessed.

Treatment of life-threatening hypercapnia with isoflurane in an infant with status asthmaticus

We encountered a 2-year-old child with life-threatening hypercapnia, with a PaCO2 of 238xa0mm Hg and severe respiratory and metabolic acidosis, due to status asthmaticus that was refractory to steroid and bronchodilator therapy. Suspecting ventilatory failure and excessive ventilation-induced obstructive shock, we started respiratory physiotherapy in synchrony with her respiration, to facilitate exhalation from her over-inflated lungs. Isoflurane inhalation was commenced in preparation for extracorporeal circulation, to reduce the hypercapnia. The combination of respiratory physiotherapy and isoflurane inhalation resulted in a rapid decrease in ventilatory resistance and PaCO2 levels within a few minutes, with recovery of consciousness within 60xa0min. Isoflurane inhalation was gradually discontinued and steroid and aminophylline therapy were commenced. The patient recovered completely without any recurrence of her bronchospasm and without any residual neurological deficits. In our patient with a severe asthmatic attack, decreased exhalation secondary to asthma and overventilation during artificial ventilation resulted in overinflation of the lungs, which in turn led to cerebral edema and obstructive cardiac failure. The favorable outcome in this case was due to the short duration of hypercapnia. Hence, we conclude that the duration of hypercapnia is an important determinant of the morbidity and mortality of status asthmaticus-induced severe hypercapnia.

Effect of sevoflurane anesthesia on the comprehensive mRNA expression profile of the mouse hippocampus

Postoperative nausea and vomiting (PONV) is a common complication after general anesthesia. Recent studies suggested that the hippocampus is involved in PONV. Hypothesising that hippocampal dopaminergic neurons are related to PONV, we examined the comprehensive mRNA profile of the hippocampus, using a sevoflurane-treated mouse model to confirm this. This study was conducted after approval from our institutional animal ethics committee, the Animal Research Center of Sapporo Medical University School of Medicine (project number: 12-033). Eight mice were assigned to two groups: a naοve group and a sevoflurane group (Sev group). In the Sev group, four mice were anesthetised with 3.5% sevoflurane for 1 hour. Subsequently, mRNA was isolated from their hippocampal cells and RNA sequencing was performed on an Illumina HiSeq 2500 platform. Mapping of the quality-controlled, filtered paired-end reads to mouse genomes and quantification of the expression levels of each gene were performed using R software. The Rtn4rl2 gene that encodes the Nogo receptor was the most up-regulated gene in the present study. The expression levels of dopamine receptor genes and the tachykinin gene were increased by sevoflurane exposure, while the genes related to serotonin receptors were not altered by sevoflurane exposure. The expression levels of LIM-homeodomain-related genes were highly down-regulated by sevoflurane. These findings suggest that sevoflurane exposure induces dopaminergic stimulation of hippocampal neurons and triggers PONV, while neuronal inflammation caused by LIM-homeodomain-related genes is down-regulated by sevoflurane.