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

Sirirat Tribuddharat,1 Thepakorn Sathitkarnmanee,1 Kriangsak Ngamsaengsirisup,1 Chawalit Wongbuddha2 1Department of Anesthesiology, 2Division of Cardiothoracic Surgery, Department of Surgery, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand 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 intraoperative 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 intraoperative 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. Keywords: predictive models, validation studies, cardiac surgical procedures, cardiopulmonary bypass, intensive care units, OHIR scor

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

Thepakorn Sathitkarnmanee, Sirirat Tribuddharat, Duangthida Nonlhaopol, Maneerat Thananun, Wilawan Somdee Department of Anesthesiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand 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. Keywords: low flow anesthesia, wash-in, desflurane, ai

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

Sunchai Theerapongpakdee, Thepakorn Sathitkarnmanee, Sirirat Tribuddharat, Siwalai Sucher, Maneerat Thananun, Duangthida Nonlhaopol Department of Anesthesiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand 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. Keywords: spontaneous breathing, anesthesia, non-rebreathing anesthetic circuit, modified Mapleson A breathing system, coaxial breathing system, rebreathin

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

Sirirat Tribuddharat,1 Thepakorn Sathitkarnmanee,1 Amnat Kitkhuandee,2 Sunchai Theerapongpakdee,1 Kriangsak Ngamsaengsirisup,1 Sarinya Chanthawong,11Department of Anesthesiology, 2Department of Surgery, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand Abstract: 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. Keywords: cefazolin, adverse effect, drug hypersensitivity, brain edema, hypertensio