Topical application of tranexamic acid to bleeding wound surfaces reduces blood loss in patients undergoing some major surgeries, without systemic complications. The objective of the present trial was to assess the efficacy and safety of the topical application of tranexamic acid on postoperative blood loss in patients undergoing primary unilateral total knee arthroplasty with cement. In a prospective, double-blind, placebo-controlled trial, 124 patients were randomized to receive 1.5 or 3.0 g of tranexamic acid in 100 mL of normal saline solution or an equivalent volume of placebo (normal saline solution) applied into the joint for five minutes at the end of surgery. The primary outcome was blood loss calculated from the difference between the preoperative hemoglobin level and the corresponding lowest postoperative value or hemoglobin level prior to transfusion. The safety outcomes included Doppler ultrasound in all patients and measurement of plasma levels of tranexamic acid one hour after release of the tourniquet. Twenty-five patients were withdrawn for various reasons; therefore, ninety-nine patients were included in the intention-to-treat analysis. The postoperative blood loss was reduced in the 1.5 and 3-g tranexamic acid groups (1295 mL [95% confidence interval, 1167 to 1422 mL] and 1208 mL [95% confidence interval, 1078 to 1339 mL], respectively) in comparison with the placebo group (1610 mL [95% confidence interval, 1480 to 1738 mL]) (p < 0.017). The postoperative hemoglobin levels were higher in the 1.5 and 3.0-g tranexamic acid groups (10.0 g/dL [95% confidence interval, 9.5 to 10.4 g/dL] and 10.1 g/dL [95% confidence interval, 9.8 to 10.5 g/dL], respectively) in comparison with the placebo group (8.6 g/dL [95% confidence interval, 8.2 to 9 g/dL]) (p < 0.017). With the numbers studied, there was no difference in the rates of deep-vein thrombosis or pulmonary embolism between the three groups. Minimal systemic absorption of tranexamic acid was observed. At the conclusion of a total knee arthroplasty with cement, topical application of tranexamic acid directly into the surgical wound reduced postoperative bleeding by 20% to 25%, or 300 to 400 mL, resulting in 16% to 17% higher postoperative hemoglobin levels compared with placebo, with no clinically important increase in complications being identified in the treatment groups. Therapeutic Level I. See Instructions to Authors for a complete description of levels of evidence.

Chronic opioid use has been associated with the development of sleep-disordered breathing (SDB) such as central sleep apnea (CSA). Patients receiving chronic opioids may suffer from unrecognized sleep apnea that contributes to opioid-overdose death. Currently, information regarding the perioperative management of patients with chronic opioid-associated CSA is limited. The objectives of this review are to define the clinical manifestations of SDB associated with chronic opioid therapy, especially CSA, and to highlight their prevalence, mechanisms, risk factors, and perioperative management. We searched Medline (1983–2014), Medline In-Process and other nonindexed citations (July 2014), EMBASE (1983–2014), the Cochrane Database of Systematic Reviews (January 2005–2014), the Cochrane Central Registry of Controlled Trials (July 2014), and PubMed basic search for new materials (1983–2014). Anesthesia and Sleep Medicine meeting abstracts were also searched for relevant articles. We included all prospective, retrospective studies and case reports in which CSA and chronic opioid use was confirmed by polysomnography. CSA was defined as the absence of airflow for ≥10 seconds with the absence of breathing efforts. A Central Apnea Index ≥5 events/h was considered significant. The search strategy yielded 8 studies which included 560 patients. The overall prevalence of CSA in patients taking chronic opioids was high (24%). The morphine equivalent daily dose (MEDD) was strongly associated with the severity of the SDB, predominantly CSA, with an MEDD of >200 mg being a threshold of particular concern. Concurrent use of benzodiazepines or hypnotics was associated with the severity of CSA in one study. Body mass index was inversely related to the severity of SDB. There were various recommendations regarding the best type of positive airway pressure therapy for the treatment of opioid-associated CSA. Continuous positive airway pressure may be ineffective in eliminating, or may even increase, CSA. Adaptive servoventilation and bilevel positive airway pressure ventilation were effective according to some reports. The overall prevalence of CSA in patients taking chronic opioids was 24%. The most important risk factors for severity of CSA were an MEDD >200 mg, and low or normal body mass index. Continuous positive airway pressure is often ineffective for treating CSA. Limited data are available on the perioperative management of patients with CSA associated with chronic opioid use. Further prospective studies on the perioperative risks and management of these patients are needed.

Spinal reconstructive surgery in adults can be associated with significant blood loss, often requiring allogeneic blood transfusion. The objective of this randomized, prospective, double-blind, multicenter study was to evaluate the efficacy of tranexamic acid (TXA) in reducing perioperative blood loss and transfusion in adult patients having elective posterior thoracic/lumbar instrumented spinal fusion surgery. One hundred fifty-one adult patients were randomized to receive either a bolus of 10 mg/kg IV of TXA after induction followed by a maintenance infusion of 1 mg/kg/hr of TXA, or an equivalent volume of placebo (normal saline). The primary outcome was the total perioperative estimated and calculated blood loss intraoperatively and 24 h postoperatively. Secondary outcomes were incidence of allogeneic blood exposure, and duration of hospital stay. Four patients were withdrawn for identifiable surgical bleeding, therefore 147 patients were included in the analysis. The total estimated and calculated perioperative blood loss was approximately 25% and 30% lower in patients given TXA versus placebo (1592 +/- 1315 mL vs 2138 +/- 1607 mL, P = 0.026; 3079 +/- 2558 vs 4363 +/- 3030, P = 0.017), respectively. There was no difference in the amounts of blood products transfused, and length of stay between the two groups. TXA, surgical duration, and number of vertebrae fused were independent factors related to perioperative blood loss. Predictors for the need for allogeneic red blood cell transfusion were ASA classification, surgical duration and number of levels fused. TXA significantly reduced the estimated and calculated total amount of perioperative blood loss in adult patients having elective posterior thoracic/lumbar instrumented spinal fusion surgery.

Objective: This systematic review and meta-analysis aim to evaluate the risk factors associated with postoperative opioid-induced respiratory depression (OIRD). Design: Systematic review and meta-analysis. Data sources: PubMed-MEDLINE, MEDLINE in-process, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, PubMed and Clinicaltrials.gov (January 1946 to November 2017). Eligibility criteria: The inclusion criteria were: (1) adult patients 18 years or older who were administered opioids after surgery and developed postoperative OIRD (OIRD group); (2) all studies which reported both OIRD events and associated risk factors; (3) all studies with reported data for each risk factor on patients with no OIRD (control group) and (4) published articles in English language. Data analysis: We used a random effects inverse variance analysis to evaluate the existing evidence of risk factors associated with OIRD. Newcastle-Ottawa scale scoring system was used to assess quality of study. Results: Twelve observational studies were included from 8690 citations. The incidence of postoperative OIRD was 5.0 cases per 1000 anaesthetics administered (95% CI: 4.8 to 5.1; total patients: 841 424; OIRD: 4194). Eighty-five per cent of OIRD occurred within the first 24 hours postoperatively. Increased risk for OIRD was associated with pre-existing cardiac disease (OIRD vs control: 42.8% vs 29.6%; OR: 1.7; 95% CI: 1.2 to 2.5; I ² : 0%; p<0.002), pulmonary disease (OIRD vs control: 17.8% vs 10.3%; OR: 2.2; 95% CI: 1.3 to 3.6; I ² : 0%; p<0.001) and obstructive sleep apnoea (OIRD vs control: 17.9% vs 16.5%; OR: 1.4; 95% CI: 1.2 to 1.7; I ² : 31%; p=0.0003). The morphine equivalent daily dose of the postoperative opioids was higher in the OIRD group than in the control; (24.7±14 mg vs 18.9±13.0 mg; mean difference: 2.8; 95% CI: 0.4 to 5.3; I ² : 98%; p=0.02). There was no significant association between OIRD and age, gender, body mass index or American Society of Anesthesiologists physical status. Conclusion: Patients with cardiac, respiratory disease and/or obstructive sleep apnoea were at increased risk for OIRD. Patients with postoperative OIRD received higher doses of morphine equivalent daily dose.

Obesity hypoventilation syndrome (OHS) is defined by the triad of obesity, daytime hypoventilation, and sleep-disordered breathing without an alternative neuromuscular, mechanical, or metabolic cause of hypoventilation. It is a disease entity distinct from simple obesity and obstructive sleep apnea. OHS is often undiagnosed but its prevalence is estimated to be 10-20% in obese patients with obstructive sleep apnea and 0.15-0.3% in the general adult population. Compared with eucapnic obese patients, those with OHS present with severe upper airway obstruction, restrictive chest physiology, blunted central respiratory drive, pulmonary hypertension, and increased mortality. The mainstay of therapy is noninvasive positive airway pressure. Currently, information regarding OHS is extremely limited in the anesthesiology literature. This review will examine the epidemiology, pathophysiology, clinical characteristics, screening, and treatment of OHS. Perioperative management of OHS will be discussed last.