Peri-Operative Wearables in Elder Recover after Surgery (POWERS) study: a protocol for a multicentre, prospective cohort study to evaluate perioperative activity with postoperative disability in older adults after non-cardiac surgery.

INTRODUCTION: The ageing population has led to an increasing proportion of surgical patients with greater frailty and comorbidity. Complications and mortality within 30 days of a surgical procedure are often used to evaluate success in the perioperative period however these measures can potentially underestimate a substantial level of morbidity associated with surgery. Personal wearable technologies are now readily available and can offer detailed information on activity intensity, sedentary behaviour and sleeping patterns. These devices may provide important information perioperatively by acting as a non-invasive, and cost-efficient means to risk stratify patients. METHODS AND ANALYSIS: The Peri-Operative Wearables in Elder Recover After Surgery (POWERS) study is a multicentre observational study of 200 older adults (≥65 years) having major elective non-cardiac surgery. The objectives are to characterise the association between preoperative and postoperative activity monitor measurements with postoperative disability and recovery, as well as characterise trajectories of activity and sleep in the perioperative period. Activity will be monitored with the ActiGraph GT3X device and measured for 7-day increments, preoperatively, and at 1 week, 1 month and 3 months postoperatively. Disability will be assessed using the WHO Disability Assessment Schedule 2.0 assessed at 1 week, 1 month and 3 months postoperatively. ETHICS AND DISSEMINATION: The POWERS study received research ethics board approval at all participating sites on 1 August 2019 (REB # 19-121 (CTO 1849)). Renewal was granted on 19 May 2022.

Functional Improvement Trajectories After Surgery (FIT After Surgery) study: protocol for a multicentre prospective cohort study to evaluate significant new disability after major surgery in older adults.

INTRODUCTION: Older adults prioritise surviving surgery, but also preservation of their functional status and quality of life. Current approaches to measure postoperative recovery, which focus on death, complications and length of hospitalisation, may miss key relevant domains. We propose that postoperative disability is an important patient-centred outcome to measure intermediate-to-long recovery after major surgery in older adults. METHODS AND ANALYSIS: The Functional Improvement Trajectories After Surgery (FIT After Surgery) study is a multicentre cohort study of 2000 older adults (≥65 years) having major non-cardiac surgery. Its objectives are to characterise the incidence, trajectories, risk factors and impact of new significant disability after non-cardiac surgery. Disability is assessed using WHO Disability Assessment Schedule (WHODAS) 2.0 instrument and participants' level-of-care needs. Disability assessments occur before surgery, and at 1, 3, 6, 9 and 12 months after surgery. The primary outcome is significantly worse WHODAS score or death at 6 months after surgery. Secondary outcomes are (1) significantly worse WHODAS score or death at 1 year after surgery, (2) increased care needs or death at 6 months after surgery and (3) increased care needs or death at 1 year after surgery. We will use multivariable logistic regression models to determine the association of preoperative characteristics and surgery type with outcomes, joint modelling to characterise longitudinal time trends in WHODAS scores over 12 months after surgery, and longitudinal latent class mixture models to identify clusters following similar trajectories of disability. ETHICS AND DISSEMINATION: The FIT After Surgery study has received research ethics board approval at all sites. Recruitment began in December 2019 but was placed on hold in March 2020 because of the COVID-19 pandemic. Recruitment was gradually restarted in October 2020, with 1-year follow-up expected to finish in 2023. Publication of the primary results is anticipated to occur in 2024.

Hepatitis C Contamination of Medication Vials Accessed with Sterile Needles and Syringes.

BACKGROUND: Health care-associated hepatitis C virus outbreaks from contaminated medication vials continue to be reported even though most practitioners deny reusing needles or syringes. The hypothesis was that when caring for hepatitis C virus-infected patients, healthcare providers may inadvertently contaminate the medication vial diaphragm and that subsequent access with sterile needles and syringes can transfer hepatitis C virus into the medication, where it remains stable in sufficient quantities to infect subsequent patients. METHODS: A parallel-arm lab study (n = 9) was performed in which contamination of medication vials in healthcare settings was simulated using cell culture-derived hepatitis C virus. First, surface-contaminated vials were accessed with sterile needles and syringes, and then hepatitis C virus contamination was assessed in cell culture. Second, after contaminating several medications with hepatitis C virus, viral infectivity over time was assessed. Last, surface-contaminated vial diaphragms were disinfected with 70% isopropyl alcohol to determine whether disinfection of the vial surface was sufficient to eliminate hepatitis C virus infectivity. RESULTS: Contamination of medication vials with hepatitis C virus and subsequent access with sterile needles and syringes resulted in contamination of the vial contents in sufficient quantities to initiate an infection in cell culture. Hepatitis C virus remained viable for several days in several commonly used medications. Finally, a single or 2- to 3-s wipe of the vial diaphragm with 70% isopropyl alcohol was not sufficient to eliminate hepatitis C virus infectivity. CONCLUSIONS: Hepatitis C virus can be transferred into commonly used medications when using sterile single-use needles and syringes where it remains viable for several days. Furthermore, cleaning the vial diaphragm with 70% isopropyl alcohol is not sufficient to eliminate the risk of hepatitis C virus infectivity. This highlights the potential risks associated with sharing medications between patients.

A survey of medication preparation and administration practices among members of the Canadian Anesthesiologists' Society.

PURPOSE: Recommendations for safe medication injection practices to eliminate the risk of patient-to-patient transmission of blood-borne infections have been in place for many years. The purpose of our study was to evaluate the medication administration practices of Canadian anesthesiologists relative to current safe practice guidelines. METHODS: An anonymous 17-question online survey was sent to all members of the Canadian Anesthesiologists' Society (CAS) via the membership email list. Data pertaining to respondent demographics, practice characteristics, and medication preparation and administration practices were collected and analyzed descriptively using frequencies and percentages as well as Fisher's exact tests followed by post hoc multiple comparisons. RESULTS: Of the 2,656 CAS members, 546 (21%) responded. The practice of reusing needles (2%) and/or syringes (7%) between patients is reported by only a minority of practitioners; however, sharing a medication vial between more than one patient using new needles and syringes is still widely practiced with 83% doing this sometimes or routinely. The main reasons for sharing medications include the desire to reduce medication waste and the associated costs. CONCLUSION: Sharing medication vials between multiple patients is common practice in Canada, with new needles and syringes used for each patient. Unfortunately, a small minority of anesthesiologists continue to reuse needles and/or syringes between patients, and this may pose a significant risk of patient-to-patient infection transmission.

Age Does Not Affect Metoprolol's Effect on Perioperative Outcomes (From the POISE Database).

BACKGROUND: Perioperative ß-blockade reduces the incidence of myocardial infarction but increases that of death, stroke, and hypotension. The elderly may experience few benefits but more harms associated with ß-blockade due to a normal effect of aging, that of a reduced resting heart rate. The tested hypothesis was that the effect of perioperative ß-blockade is more significant with increasing age. METHODS: To determine whether the effect of perioperative ß-blockade on the primary composite event, clinically significant hypotension, myocardial infarction, stroke, and death varies with age, we interrogated data from the perioperative ischemia evaluation (POISE) study. The POISE study randomly assigned 8351 patients, aged ≥45 years, in 23 countries, undergoing major noncardiac surgery to either 200 mg metoprolol CR daily or placebo for 30 days. Odds ratios or hazard ratios for time to events, when available, for each of the adverse effects were measured according to decile of age, and interaction term between age and treatment was calculated. No adjustment was made for multiple outcomes. RESULTS: Age was associated with higher incidences of the major outcomes of clinically significant hypotension, myocardial infarction, and death. Age was associated with a minimal reduction in resting heart rate from 84.2 (standard error, 0.63; ages 45-54 years) to 80.9 (standard error, 0.70; ages >85 years; P < .0001). We found no evidence of any interaction between age and study group regarding any of the major outcomes, although the limited sample size does not exclude any but large interactions. CONCLUSIONS: The effect of perioperative ß-blockade on the major outcomes studied did not vary with age. Resting heart rate decreases slightly with age. Our data do not support a recommendation for the use of perioperative ß-blockade in any age subgroup to achieve benefits but avoid harms. Therefore, current recommendations against the use of ß-blockers in high-risk patients undergoing noncardiac surgery apply across all age groups.

Managing the perioperative patient on direct oral anticoagulants.

PURPOSE: Patients are increasingly treated with direct oral anticoagulants (DOACs) for the prevention of stroke due to non-valvular atrial fibrillation and for the treatment of venous thromboembolism. When these patients present for urgent or emergent surgical procedures, they present a challenge to the anesthesiologist who must manage perioperative risk due to anticoagulation. The purpose of this module is to review the literature surrounding the perioperative management of DOACs. Timing, laboratory monitoring, and availability of reversal agents are important considerations to optimize patients being treated with DOACs who require emergent surgery. PRINCIPAL FINDINGS: Laboratory tests are not recommended for routine monitoring of DOACs since they do not correlate well with anticoagulant activity. Most widely available laboratory tests lack the sensitivity to detect anticoagulant effects at low plasma concentrations. However, a normal thrombin time for dabigatran excludes clinically significant drug levels. If the risk of bleeding is judged to be high because of a recent dose of DOAC, various options are available to mitigate bleeding. When possible, surgery should be delayed for at least 12 hr after the last dose of DOAC. Activated charcoal may mitigate the anticoagulant effect caused by DOACs if administered less than two hours after the drug was ingested. Four-factor prothrombin complex concentrates (PCCs) may be useful to reduce life-threatening bleeding associated with factor Xa inhibitors. Activated PCCs have been shown to reverse abnormal coagulation tests associated with all DOACs, but there is a lack of reported evidence of clinical benefit. Idarucizumab is a specific antidote that is effective for reversal of anticoagulation due to dabigatran. An antidote for rivaroxaban and apixaban (andexanet alfa) as well as a universal antidote for all DOACs and heparin (PER977) are in clinical development. CONCLUSION: Perioperative management of anticoagulation due to DOACs is a growing concern as the number of patients prescribed these medications increases each year. These patients can be safely optimized for urgent or emergent surgery by giving appropriate consideration to timing, monitoring, and reversal agents.

Postoperative dysglycemia in elective non-diabetic surgical patients: a prospective observational study.

PURPOSE: Elevated glycosylated hemoglobin (HbA1c) is often found in surgical patients with no history of diabetes. The purpose of this prospective observational study was to determine if elevated preoperative HbA1c is associated with postoperative hyperglycemia in non-diabetic surgical patients and to identify predictors of elevated HbA1c. METHODS: This study included 257 non-diabetic adults scheduled for inpatient surgery. Preoperatively, capillary blood glucose (CBG) and HbA1c were measured and patients completed the Canadian Diabetes Risk Questionnaire (CANRISK). Capillary blood glucose was measured for two days or until hospital discharge at the following time points: postoperatively, before all meals, and at 22:00 hr. The mean CBG and incidence of hyperglycemia were compared between HbA1c levels: Group I < 6.0%, Group II 6.0-6.4%, and Group III ≥ 6.5%. RESULTS: The mean postoperative glucose levels at all time points were significantly higher in Group III compared with Groups I and II (P < 0.01). At least one episode of hyperglycemia (CBG ≥ 10.0 mMol·L-1) occurred in 61% (11/18) of patients in Group III vs 11% (23/209) of patients in Group I (relative risk, 5.55; 95% confidence interval [CI], 3.26 to 9.47; P < 0.001). Elevated glycosylated hemoglobin ≥ 6.0% was found in 31% (33/107) of those with a high CANRISK score. The best predictors of postoperative hyperglycemia were preoperative CBG > 6.9 mMol·L-1 [diagnostic odds ratio (OR) (reference < 6.0 mMol·L-1), 4.16; 95% CI, 1.57 to 10.98; P = 0.004], HbA1c ≥ 6.0% [OR (reference < 6.0%), 3.00; 95% CI, 1.39 to 6.49; P = 0.005], and HbA1c ≥ 6.5% [OR (reference < 6.5%), 13.45; 95% CI, 4.78 to 37.84; P <0.001]. CONCLUSIONS: Elevated HbA1c is associated with higher mean postoperative glucose levels in patients with no diabetic history. The CANRISK score is a strong predictor of elevated HbA1c, while CBG and HbA1c are both predictors of postoperative hyperglycemia.

Reversal of warfarin anticoagulation for urgent surgical procedures.

PURPOSE: Patients treated with warfarin for therapeutic anticoagulation present a challenge for the perioperative management of urgent and emergent surgery. Anticoagulation must be reversed prior to most surgical procedures to prevent intraoperative bleeding. The purpose of this module is to review the options for urgent reversal of warfarin anticoagulation and the indications for each reversal agent. Selection of the appropriate agent is important to reduce unnecessary complications of treatment and to achieve optimal reversal of anticoagulation. PRINCIPAL FINDINGS: When urgent surgery is required for patients taking warfarin, intravenous vitamin K1 should be used for procedures that can be delayed for six to 12 hr. Vitamin K1 results in the activation of existing clotting factors rather than requiring the synthesis of new proteins, which allows for its relatively rapid onset of action. Intravenous vitamin K1 acts more quickly than oral administration, with reversal of anticoagulation occurring within six to 12 hr vs 18-24 hr, respectively. If surgery cannot be delayed, prothrombin complex concentrates (PCCs) should be given, and intravenous vitamin K1 should be infused concurrently to ensure sustained reversal of anticoagulation. The duration of action of both PCCs and plasma is six hours due to the short half-life of factor VII. Prothrombin complex concentrates contain small amounts of heparin and are contraindicated in patients with heparin-induced thrombocytopenia. Plasma should be used only if PCCs are unavailable or are contraindicated. CONCLUSION: Reversal of warfarin anticoagulation can be achieved in a safe and timely manner when the appropriate agent is selected and administered correctly.

Preoperative beta blocker use associated with cerebral ischemia during carotid endarterectomy.

PURPOSE: Cerebral ischemia is a known complication of carotid cross-clamping during carotid endarterectomy. Selective intraluminal shunting for cerebral protection is not always effective and carries risks. The purpose of this study was to identify potentially modifiable risk factors for intraoperative cerebral ischemia and shunting during carotid endarterectomy. METHODS: We performed an historical case-control chart review of primary carotid endarterectomies with electroencephalographic (EEG) monitoring and selective shunting. Randomized controls and cases that showed ischemic EEG changes and required shunting were matched by year of surgery and the presence or absence of a contralateral carotid occlusion. Detailed perioperative data were collected for all cases. Results were analyzed using the Mantel-Haenszel test, analysis of variance, and a multivariate logistic regression model. RESULTS: Of 523 charts screened, 69 patients had experienced evidence of cerebral ischemia on clamping of the carotid and required shunting. These patients were more likely than their matched controls to have been receiving regular preoperative beta blockers (33/69 vs 18/69, respectively; P = 0.01; odds ratio [OR] 2.5; 95% confidence interval [CI] 1.2 to 5.1). Ipsilateral moderate carotid stenosis (60-80%) was also associated with increased risk. An adjusted multivariate regression model estimated an OR of 3.6 (95% CI 1.5 to 8.9; P = 0.005) for the association between use of a beta blocker and shunting. Intraoperative hemodynamic values were similar for the shunt and control groups as well as for patients receiving and not receiving preoperative beta blockers. CONCLUSION: The current study found an association between regular preoperative use of beta blockers and intraoperative cerebral ischemia in patients undergoing carotid endarterectomy. This effect did not relate to intraoperative hemodynamics.

An observational cohort study to assess glycosylated hemoglobin screening for elective surgical patients.

INTRODUCTION: Uncontrolled blood glucose is associated with a higher incidence of surgical site infections, greater utilization of resources, and increased mortality. Preoperative screening for diabetes in elective surgical patients is not routinely performed. The purpose of this study was to examine blood glucose control in a preoperative surgical population. METHODS: Following ethics approval, adults presenting to the pre-surgical screening clinic in preparation for elective surgery were recruited. Data collection included a self-administered questionnaire on diabetic risk factors and blood glucose testing, including glycosylated hemoglobin (HbA1c). Descriptive analyses were conducted. RESULTS: Seventy of the 402 participants (17.4%) had a previous diagnosis of diabetes (diabetics). Among those without a history of diabetes (n = 332 non-diabetics), 23.2% (n = 77) were considered very high risk for diabetes (HbA1c = 6.0-6.4%), and 3.9% (n = 13) had a provisional diagnosis of diabetes (HbA1c ≥ 6.5%). Fifty-six percent (n = 39/70) of diabetics had suboptimal glycemic control (HbA1c > 7.0%), and 51.3% (n = 20/39) of this subgroup presumed their blood sugars were reasonably or very well controlled. Fifteen percent (n = 2/13) of patients with a provisional diagnosis of diabetes (HbA1c ≥ 6.5%) had an elevated random blood sugar (RBS) (≥ 11.1 mmol·L(-1)), while 67% (n = 8/12) had an elevated fasting blood sugar (FBS) (≥ 7.0 mmol·L(-1)). Forty-two percent (n = 16/38) of suboptimally controlled diabetics (HbA1c > 7.0%) had an elevated RBS (≥ 11.1 mmol·L(-1)), and 86% (n = 31/36) had an elevated FBS (≥ 7.0 mmol·L(-1)). DISCUSSION: Many elective surgical patients are at risk for unrecognized postoperative hyperglycemia and associated adverse outcomes. Random blood sugar testing has limited value and HbA1c may be a more appropriate test for the preoperative assessment of diabetic patients.

Day of surgery cancellation rates in urology: Identification of modifiable factors.

OBJECTIVE: Day-of-surgery cancellations have a negative effect on operating room (OR) resources, as well as on patient satisfaction and perception of quality of care. Given increasing wait times in a universal healthcare system and the nature of urological surgery in our aging population, it should be a priority to identify modifiable risks of OR cancellations to assure timely and efficient delivery of care. We explore the rate and reasons for elective surgery cancellations in a Canadian urological practice. METHODS: We evaluated the rate and reason of urological surgery cancellation at a single academic institution, prospectively collected in our centre's Operating Room Scheduling Office System (ORSOS) database. Documented reasons for cancellations were divided into 3 components: (1) structural factors (e.g., no hospital bed); (2) patient factors (e.g., patient unwell); and (3) process factors (e.g., scheduling error). Rates and reasons for cancellations were compared to those of General Surgery and Gynecology. The documented reasons for cancellation in the ORSOS database were confirmed or extended by chart review and interviews with a subset of cancelled patients. RESULTS: Between 2005 and 2009, 1544 out of 19 141 (8.07 %) elective surgical cases were cancelled within the three surgical specialties (general surgery, gynecology and urology); urology had the highest average rate of 9.53%. Non-oncological cases represented a higher percentage of cancelled cases (15%, p < 0.001) and overall rates varied significantly over time in urology compared to the other surgical specialties. Potentially modifiable, process-related causes were by far the most common reason for cancellation (58.5%) and "standby" cases were a common cause of overall cancellation rates. Patient interviews confirmed the emotional and financial impact of cancellation; there was no overwhelming concern that clinical outcomes were negatively affected. CONCLUSIONS: This contemporary exploration of cancelled urological cases is consistent with previous reports, although variable over time and dependent on definitions used. Potentially modifiable, process-related factors appear to be most frequently associated with cancellation, although more thorough and detailed documentation is required to further mitigate inefficient OR use. We suggest that all OR cancellations should be considered to be adverse incidents to be monitored by institutions in a systematic fashion.

Canadian Cardiovascular Society/Canadian Anesthesiologists' Society/Canadian Heart Rhythm Society joint position statement on the perioperative management of patients with implanted pacemakers, defibrillators, and neurostimulating devices.

There are more than 200,000 Canadians living with permanent pacemakers or implantable defibrillators, many of whom will require surgery or invasive procedures each year. They face potential hazards when undergoing surgery; however, with appropriate planning and education of operating room personnel, adverse device-related outcomes should be rare. This joint position statement from the Canadian Cardiovascular Society (CCS) and the Canadian Anesthesiologists' Society (CAS) has been developed as an accessible reference for physicians and surgeons, providing an overview of the key issues for the preoperative, intraoperative, and postoperative care of these patients. The document summarizes the limited published literature in this field, but for most issues, relies heavily on the experience of the cardiologists and anesthesiologists who contributed to this work. This position statement outlines how to obtain information about an individual's type of pacemaker or implantable defibrillator and its programming. It also stresses the importance of determining if a patient is highly pacemaker-dependent and proposes a simple approach for nonelective evaluation of dependency. Although the document provides a comprehensive list of the intraoperative issues facing these patients, there is a focus on electromagnetic interference resulting from electrocautery and practical guidance is given regarding the characteristics of surgery, electrocautery, pacemakers, and defibrillators which are most likely to lead to interference. The document stresses the importance of preoperative consultation and planning to minimize complications. It reviews the relative merits of intraoperative magnet use vs reprogramming of devices and gives examples of situations where one or the other approach is preferable.

Society position statement : Canadian Cardiovascular Society/Canadian Anesthesiologists' Society/Canadian Heart Rhythm Society joint position statement on the perioperative management of patients with implanted pacemakers, defibrillators, and neurostimulating devices.

PURPOSE: There are more than 200,000 Canadians living with permanent pacemakers or implantable defibrillators, many of whom will require surgery or invasive procedures each year. They face potential hazards when undergoing surgery; however, with appropriate planning and education of operating room personnel, adverse device-related outcomes should be rare. This joint position statement from the Canadian Cardiovascular Society (CCS) and the Canadian Anesthesiologists' Society (CAS) has been developed as an accessible reference for physicians and surgeons, providing an overview of the key issues for the preoperative, intraoperative, and postoperative care of these patients. PRINCIPAL FINDINGS: The document summarizes the limited published literature in this field, but for most issues, relies heavily on the experience of the cardiologists and anesthesiologists who contributed to this work. This position statement outlines how to obtain information about an individual's type of pacemaker or implantable defibrillator and its programming. It also stresses the importance of determining if a patient is highly pacemaker-dependent and proposes a simple approach for nonelective evaluation of dependency. Although the document provides a comprehensive list of the intraoperative issues facing these patients, there is a focus on electromagnetic interference resulting from electrocautery and practical guidance is given regarding the characteristics of surgery, electrocautery, pacemakers, and defibrillators which are most likely to lead to interference. CONCLUSIONS: The document stresses the importance of preoperative consultation and planning to minimize complications. It reviews the relative merits of intraoperative magnet use vs reprogramming of devices and gives examples of situations where one or the other approach is preferable.

Easily adoptable total joint arthroplasty program allows discharge home in two days.

PURPOSE: A safe efficient care pathway is needed to address the increasing need for arthroplasty surgery in Canada. Our primary objective was to determine whether a fast-track model of care can reduce length of hospital stay following total hip and knee arthroplasty while maintaining patient safety and satisfaction. METHODS: In this historical cohort study, 100 patients treated in a newly implemented fast-track program for total joint arthroplasty were compared with 100 patients treated before the introduction of the program. The fast-track program emphasizes preoperative patient education, postoperative multimodal analgesia with periarticular injections, early physiotherapy and rehabilitation, and discharge home with an outpatient rehabilitation program. The primary outcome was hospital length of stay. Secondary outcomes were concerned with patient safety and involved evaluating postoperative side effects, transfers to the tertiary care hospital, and emergency department (ED) visits and readmissions to hospital within 30 days of discharge. RESULTS: Length of hospital stay adjusted for age, sex, smoking, comorbidities, American Society of Anesthesiologists' physical status classification, body mass index, and surgical procedure was reduced significantly for patients in the fast-track program compared with the standard program (mean 47 hr; 95% confidence interval [CI] 41 to 53 vs mean 116 hr; 95% CI 110 to 122, respectively). Patients in the fast-track program were discharged from hospital 69 hr earlier than patients in the standard program (95% CI -60 to -78). Despite significantly less morphine utilization, pain scores trended lower in the fast-track patients, both at rest and with activity, than in patients in the standard group (median 7.5 vs 35 mg, respectively). There were no significant differences between the two groups in the rate of ED visits or readmissions in the first 30 days. CONCLUSION: Our multimodal multidisciplinary fast-track protocol reduced hospital stay and opioid consumption while maintaining a high level of patient safety. Program implementation is feasible both in tertiary care and in community hospitals.

A comparative evaluation of capnometry versus pulse oximetry during procedural sedation and analgesia on room air.

OBJECTIVE: Important questions remain regarding how best to monitor patients during procedural sedation and analgesia (PSA). Capnometry can detect hypoventilation and apnea, yet it is rarely used in emergency patients. Even the routine practice of performing preoxygenation in low-risk patients is controversial, as supplementary oxygen can delay the detection of respiratory depression by pulse oximetry. The purpose of this study was to determine whether the capnometer or the pulse oximeter would first detect respiratory events in adults breathing room air. METHODS: During a randomized clinical trial comparing fentanyl with low-dose ketamine for PSA with titrated propofol, patients were monitored using pulse oximetry and continuous oral-nasal sampled capnography. Supplemental oxygen was administered only for oxygen desaturation. Sedating physicians identified prespecified respiratory events, including hypoventilation (end-tidal carbon dioxide > 50 mm Hg, rise of 10 mm Hg from baseline or loss of waveform) and oxygen desaturation (pulse oximetry < 92%). These events and their timing were corroborated by memory data retrieved from the monitors. RESULTS: Of 63 patients enrolled, 57% (36) developed brief oxygen desaturation at some point during the sedation. All responded to oxygen, stimulation or interruption of propofol. Measurements of end-tidal carbon dioxide varied substantially between and within patients before study intervention. Hypoventilation (19 patients, 30%) was only weakly associated with oxygen desaturation (crude odds ratio 1.4 [95% confidence interval 0.47 to 4.3]), and preceded oxygen desaturation in none of the 12 patients in whom both events occurred (median lag 1:50 m:ss [interquartile range 0:01 to 3:24 m:ss]). CONCLUSION: During PSA in adults breathing room air, desaturation detectable by pulse oximeter usually occurs before overt changes in capnometry are identified.

Ringer's lactate is compatible with saline-adenine-glucose-mannitol preserved packed red blood cells for rapid transfusion.

PURPOSE: Guidelines state that Ringer's lactate (RL) should not be co-administered with packed red blood cells (PRBC) due to a potential risk of clotting. The purpose of this study was to determine whether RL causes clotting in PRBC with the currently used preservative, saline-adenine-glucose-mannitol (SAGM). METHODS: Phase 1: Samples from 12 units of SAGM-PRBC were diluted from 0-97.5% with RL and normal saline (NS), incubated for 30 min, and passed through 40 µm filters. Additional samples were frozen and batch analyzed using an enzyme-linked immunosorbent assay (ELISA) to measure prothrombin activation fragment 1 + 2 (F1 + 2), indicative of thrombin generation. Packed red blood cells were also diluted, flushed with crystalloid using a rapid transfusion model, and filtered. Phase 2: Eight further units were serially diluted with RL and incubated for 30, 60, 120, 180, and 240 min. Fresh samples were analyzed by filtration and ELISA. RESULTS: Phase 1: No clotting was seen during filtration or using the transfusion model with NS or RL. The F1 + 2 ranged from 2.28 to 154.37 pmol·L⁻¹ in NS dilutions and from 2.80 to 1675.93 pmol·L⁻¹ in RL dilutions, indicating coagulation in some samples. Phase 2: No clotting was observed within 60 min by filtration or ELISA. However, 4 of the 8 units showed clots in the filters of some dilutions between 120 and 240 min. CONCLUSIONS: No clotting was detected at any dilution of RL with SAGM- preserved PRBC within 60 min, but clotting was detected with extended incubation. The results indicate RL can be safely co-administered with PRBC during rapid transfusion (< 60 min).

Ringer's lactate is compatible with the rapid infusion of AS-3 preserved packed red blood cells.

PURPOSE: Ringer's lactate (RL) may be preferable to normal saline (NS) for large volume resuscitation. Authorities recommend against its mixture with packed red blood cells (PRBC) due to a theoretical risk of clotting. The purpose of this study was to test whether RL, as compared with NS, leads to a risk of clotting when used to dilute AS-3 preserved PRBC in a clinically relevant model. METHODS: Following Ethics Board approval, eight units of unused, unexpired AS-3 preserved PRBC were obtained. Four sets of two parallel studies were performed, comparing RL with NS as the diluent for PRBC. The mixtures were infused using gravity flow through standard blood filter tubing and fluid warmer, to simulate an intraoperative blood transfusion. A series of progressively more dilute samples was collected. These were filtered and analyzed macroscopically, then using enzyme-linked immunosorbent assay to quantify the amount of F1+2 (the breakdown products of thrombin generation). RESULTS: No filters in any of the NS and RL mixtures contained evidence of clot or debris. In the NS group, the F1+2 levels ranged from 2.7 to 38.0 pmol x L(-1). In the RL group, the F1+2 levels ranged from 3.2 to 289.7 pmol x L(-1). All of these values were below the physiologic levels determined in previous studies. CONCLUSION: In this simulation of intraoperative blood transfusion, RL did not lead to visible or molecular evidence of activation of the clotting cascade. The current study challenges recommendations that AS-3 PRBC should not be mixed with RL for rapid transfusion.

Subdissociative-dose ketamine versus fentanyl for analgesia during propofol procedural sedation: a randomized clinical trial.

OBJECTIVES: The authors sought to compare the safety and efficacy of subdissociative-dose ketamine versus fentanyl as adjunct analgesics for emergency department (ED) procedural sedation and analgesia (PSA) with propofol. METHODS: This double-blind, randomized trial enrolled American Society of Anesthesiology (ASA) Class I or II ED patients, aged 14-65 years, requiring PSA for orthopedic reduction or abscess drainage. Subjects received 0.3 mg/kg ketamine or 1.5 mug/kg fentanyl intravenously (IV), followed by IV propofol titrated to deep sedation. Supplemental oxygen was not routinely administered. The primary outcomes were the frequency and severity of cardiorespiratory events and interventions, rated using a composite intrasedation event rating scale. Secondary outcomes included the frequency of specific scale component events, propofol doses required to achieve and maintain sedation, times to sedation and recovery, and physician and patient satisfaction. RESULTS: Sixty-three patients were enrolled. Of patients who received fentanyl, 26/31 (83.9%) had an intrasedation event versus 15/32 (46.9%) of those who received ketamine. Events prospectively rated as moderate or severe were seen in 16/31 (51.6%) of fentanyl subjects versus 7/32 (21.9%) of ketamine subjects. Patients receiving fentanyl had 5.1 (95% confidence interval [CI] = 1.9 to 13.6; p < 0.001) times the odds of having a more serious intrasedation event rating than patients receiving ketamine. There were no significant differences in secondary outcomes, apart from higher propofol doses in the ketamine arm. CONCLUSIONS: Subdissociative-dose ketamine is safer than fentanyl for ED PSA with propofol and appears to have similar efficacy.