Thepakorn Sathitkarnmanee

Transdermal fentanyl patch for postoperative analgesia in total knee arthroplasty: a randomized double-blind controlled trial

Purpose To assess the efficacy of a transdermal fentanyl patch (TFP) (50 μg/hour) applied 10–12 hours before surgery versus placebo for postoperative pain control of total knee arthroplasty (TKA). Materials and methods We enrolled 40 patients undergoing elective TKA under spinal anesthesia using isobaric or hyperbaric bupivacaine. Subjects were randomized to receive a TFP (Duragesic® 50 μg/hour) or placebo patch applied with a self-adhesive to the anterior chest wall 10–12 hours before spinal anesthesia. Every patient was given patient-controlled morphine for postoperative pain control. Patients were evaluated every 4 hours until 48 hours. Results Morphine consumption at 24 and 48 hours in the TFP group versus the placebo group was 15.40±12.65 and 24.90±20.11 mg versus 33.60±19.06 and 57.80±12.65 mg (P≤0.001). Numeric rating scale scores at rest and during movement over 48 hours were lower in the TFP group. Ambulation and nausea/vomiting scores were statistically greater, but not clinically significant in the TFP group. Sedation scores were low and not statistically significantly different between groups. There was no severe respiratory depression. Conclusion TFP (50 μg/hour) applied 10–12 hours before surgery can effectively and safely decrease morphine consumption and pain scores during the first 48 hours after TKA surgery.

Development of an Open-Heart Intraoperative Risk Scoring Model for Predicting a Prolonged Intensive Care Unit Stay

Background. Based on a pilot study with 34 patients, applying the modified sequential organ failure assessment (SOFA) score intraoperatively could predict a prolonged ICU stay, albeit with only 4 risk factors. Our objective was to develop a practicable intraoperative model for predicting prolonged ICU stay which included more relevant risk factors. Methods. An extensive literature review identified 6 other intraoperative risk factors affecting prolonged ICU stay. Another 168 patients were then recruited for whom all 10 risk factors were extracted and analyzed by logistic regression to form the new prognostic model. Results. The multivariate logistic regression analysis retained only 6 significant risk factors in the model: age ≥ 60 years, PaO2/FiO2 ratio ≤ 200 mmHg, platelet count ≤ 120,000/mm3, requirement for inotrope/vasopressor ≥ 2 drugs, serum potassium ≤ 3.2 mEq/L, and atrial fibrillation grading ≥2. This model was then simplified into the Open-Heart Intraoperative Risk (OHIR) score, comprising the same 6 risk factors for a total score of 7—a score of ≥3 indicating a likely prolonged ICU stay (AUC for ROC of 0.746). Conclusions. We developed a new, easy to calculate OHIR scoring system for predicting prolonged ICU stay as early as 3 hours after CPB. It comprises 6 risk factors, 5 of which can be manipulated intraoperatively.

1-1-12 one-step wash-in scheme for desflurane low flow anesthesia: performance without nitrous oxide.

Background We reported a 1-1-12 wash-in scheme for desflurane-nitrous oxide (N2O) low flow anesthesia that is simple, rapid, and predictable. There remain some situations where N2O should be avoided, which limits the generalizability of this wash-in scheme. The objective of our study was to determine the performance of this scheme in contexts where N2O is not used. Methods We recruited 106 patients scheduled for elective surgery under general anesthesia. After induction and intubation, wash-in was started with a fresh gas flow of air:O2 1:1 L/min and a vaporizer concentration of desflurane of 12%. Controlled ventilation was then adjusted to maintain PACO2 at 30–35 mmHg. Results The alveolar concentration of desflurane (FAD) rose rapidly from 0% to 6% in 4 minutes in the same pattern as observed in our previous study in which N2O was used. An FAD of 7% was achieved in 6 minutes. An FAD of 1% to 7% occurred at 0.6, 1, 1.5, 2, 3, 4, and 6 minutes. The rise in heart rate during wash-in was statistically significant, although not clinically so. There was a slight but statistically significant decrease in blood pressure, but this had no clinical significance. Conclusion Performance of the 1-1-12 wash-in scheme is independent of the use of N2O. Respective FADs of 1%, 2%, 3%, 4%, 5%, 6%, and 7% can be expected at 0.6, 1, 1.5, 2, 3, 4, and 6 minutes.

1-1-12 One-Step Wash-In Scheme for Desflurane-Nitrous Oxide Low-Flow Anesthesia: Rapid and Predictable Induction

Background. We propose a 1-1-12 wash-in scheme for desflurane-nitrous oxide (N2O) low-flow anesthesia. The objective of our study was to determine the time to achieve alveolar concentration of desflurane (FAD) at 1, 2, 3, 4, 5, and 6%. Methods. We enrolled 106 patients scheduled for elective surgery under general anesthesia. After induction and intubation, wash-in was started with a fresh gas flow (FGF) of N2O : O2 1 : 1 L min−1 and vaporizer concentration of desflurane (FD) of 12%. Ventilation was controlled to maintain PACO2 at 30–35 mmHg. Results. The FAD rose rapidly from 0 to 4% in 2 min in a linear manner in 0.5 min increments. An FAD of 6% was achieved in 4 min in a linear fashion from FAD of 4% but in 1 min increments. An FAD of 1 to 6% occurred at 0.6, 1, 1.5, 2, 3, and 4 min. Heart rate during wash-in showed a statistically, albeit not clinically, significant pattern of increase. By contrast, blood pressure slightly decreased during this period. Conclusions. We developed a 1-1-12 wash-in scheme using a FGF of N2O : O2 1 : 1 L min−1 and FD of 12% for desflurane-nitrous oxide low-flow anesthesia. A respective FAD of 1, 2, 3, 4, 5, and 6% can be expected at 0.6, 1, 1.5, 2, 3, and 4 min.

Validation of Open-Heart Intraoperative Risk score to predict a prolonged intensive care unit stay for adult patients undergoing cardiac surgery with cardiopulmonary bypass

Background A prolonged stay in an intensive care unit (ICU) after cardiac surgery with cardiopulmonary bypass (CPB) increases the cost of care as well as morbidity and mortality. Several predictive models aim at identifying patients at risk of prolonged ICU stay after cardiac surgery with CPB, but almost all of them involve a preoperative assessment for proper resource management, while one – the Open-Heart Intraoperative Risk (OHIR) score – focuses on intra-operative manipulatable risk factors for improving anesthetic care and patient outcome. Objective We aimed to revalidate the OHIR score in a different context. Materials and methods The ability of the OHIR score to predict a prolonged ICU stay was assessed in 123 adults undergoing cardiac surgery (both coronary bypass graft and valvular surgery) with CPB at two tertiary university hospitals between January 2013 and December 2014. The criteria for a prolonged ICU stay matched a previous study (ie, a stay longer than the median). Results The area under the receiver operating characteristic curve of the OHIR score to predict a prolonged ICU stay was 0.95 (95% confidence interval 0.90–1.00). The respective sensitivity, specificity, positive predictive value, and accuracy of an OHIR score of ≥3 to discriminate a prolonged ICU stay was 93.10%, 98.46%, 98.18%, and 95.9%. Conclusion The OHIR score is highly predictive of a prolonged ICU stay among intraopera-tive patients undergoing cardiac surgery with CPB. The OHIR comprises of six risk factors, five of which are manipulatable intraoperatively. The OHIR can be used to identify patients at risk as well as to improve the outcome of those patients.

Comparative study of minimal fresh gas flow used in Lack-Plus and Lack’s circuit in spontaneously breathing anesthetized adults

Background The Lack’s circuit is a co-axial Mapleson A breathing system commonly used in spontaneously breathing anesthetized adults but still requires high fresh gas flow (FGF). The Lack-Plus circuit was invented with the advantage of lower FGF requirement. The authors compared the Lack-Plus and Lack’s circuit for the minimal FGF requirement with no rebreathing in spontaneously breathing anesthetized adults. Methods This was a randomized crossover study. We enrolled 24 adult patients undergoing supine elective surgery, with a body mass index ≤30 kg/m2 and an American Society of Anesthesiologists physical status I–II. They were randomly allocated to group 1 (LP-L) starting with Lack-Plus then switching to Lack’s circuit or group 2 (L-LP) (with the reverse pattern). After induction and intubation, anesthesia was maintained with 50% N2O/O2 and desflurane (4%–6%) plus fentanyl titration to maintain an optimal respiratory rate between 10 and 16/min. Starting with the first circuit, all the patients were spontaneously breathing with a FGF of 4 L/min for 10 min, gradually decreased by 0.5 L/min every 5 min until FGF was 2.5 L/min. End-tidal CO2, inspired minimum CO2 (ImCO2), mean arterial pressure, and oxygen saturation were recorded until rebreathing (ImCO2 >0 mmHg) occurred. The alternate anesthesia breathing circuit was used and the measurements were repeated. Results The respective minimal FGF at the point of rebreathing for the Lack-Plus and Lack’s circuit was 2.7±0.8 and 3.3±0.5 L/min, respectively, p<0.001. At an FGF of 2.5 L/min, the respective ImCO2 was 1.5±2.0 and 4.2±2.6 mmHg, respectively, p<0.001. Conclusion The Lack-Plus circuit can be used safely and effectively, and it requires less FGF than Lack’s circuit in spontaneously breathing anesthetized adults.

A fatal adverse effect of cefazolin administration: severe brain edema in a patient with multiple meningiomas

Cefazolin is commonly administered before surgery as a prophylactic antibiotic. Hypersensitivity to cefazolin is not uncommon, and the symptoms mostly include urticaria, skin reaction, diarrhea, vomiting, and transient neutropenia, which are rarely life threatening. We present a rare case of fatal cefazolin hypersensitivity in a female who was diagnosed with multiple meningiomas and scheduled for craniotomy and tumor removal. Immediately after cefazolin IV administration, the patient developed acute hypertensive crisis, which resolved within 10 minutes after the treatment. This was followed by unexplained metabolic acidosis. The patient then developed severe brain edema 100 minutes later. The patient had facial edema when her face was exposed for the next 30 minutes. A computed tomography scan revealed global brain edema with herniation. She was admitted to the intensive care unit for symptomatic treatment and died 10 days after surgery from multiorgan failure. The serum IgE level was very high (734 IU/mL). Single-dose administration of cefazolin for surgical prophylaxis may lead to rare, fatal adverse reaction. The warning signs are sudden, unexplained metabolic acidosis, hypertensive crisis, tachycardia, and facial angioedema predominating with or without cutaneous symptoms like urticaria.