Critical Respiratory Events Research Articles

Development and validation of a nomogram for predicting critical respiratory events during early anesthesia recovery in elderly patients

BackgroundElderly patients undergoing recovery from general anesthesia face a heightened risk of critical respiratory events (CREs). Despite this, there is a notable absence of effective predictive tools tailored to this specific demographic. This study aims to develop and validate a predictive model (nomogram) to address this gap. CREs pose significant risks to elderly patients during the recovery phase from general anesthesia, making it an important issue in perioperative care. With the increasing aging population and the complexity of surgical procedures, it is crucial to develop effective predictive tools to improve patient outcomes and ensure patient safety during post-anesthesia care unit (PACU) recovery.MethodsA total of 324 elderly patients who underwent elective general anesthesia in a grade A tertiary hospital from January 2023 to June 2023 were enrolled. Risk factors were identified using least absolute shrinkage and selection operator (LASSO) regression. A multivariate logistic regression model was constructed and represented as a nomogram. Internal validation of the model was performed using Bootstrapping. This study followed the TRIPOD checklist for reporting.ResultsThe indicators included in the nomogram were frailty, snoring, patient-controlled intravenous analgesia (PCIA), emergency delirium and cough intensity at extubation. The diagnostic performance of the nomogram model was satisfactory, with AUC values of 0.990 and 0.981 for the training set and internal validation set, respectively. The optimal cutoff value was determined to be 0.22, based on a Youden index of 0.911. The F1-score was 0.927, and the MCC was 0.896. The calibration curve, Brier score (0.046), and HL test demonstrated acceptable consistency between the predicted and actual results. DCA revealed high net benefits of the nomogram prediction across all threshold probabilities.ConclusionsThis study developed and validated a nomogram to identify elderly patients in the PACU who are at higher risk of CREs. The identified predictive factors included frailty condition, snoring syndrome, PCIA, emergency delirium, and cough intensity at extubation. By identifying patients at higher risk of CREs early on, medical professionals can implement targeted strategies to mitigate the occurrence of complications and provide better postoperative care for elderly patients recovering from general anesthesia.

Opioid-free General Anesthesia and Awake Fiberoptic Intubation with Dexmedetomidine in a Class IV Obese Patient with Cervical Spondylosis

Abstract Patients with Class IV obesity (C4O) (body mass index [BMI] >50 kg/m2) are at a particularly high risk of anesthesia-related complications during the postoperative period, e.g., critical respiratory events (CREs) including respiratory arrest and oversedation, leading to problems with maintaining open airway, hypoxia, and hypercapnia. We present the case of a 67-year-old C4O (BMI 57.2 kg/m2) female patient with cervical spondylosis, scheduled for laparoscopic sleeve gastrectomy. Preanesthesia evaluation revealed hypertension, type 2 diabetes mellitus (DM), nonalcoholic steatohepatitis, and obstructive sleep apnea as comorbidities. Awake fiberoptic intubation was planned because of a high potential for difficult intubation (neck circumference of 45 cm, cervical spondylosis, reduced neck mobility, and type 2 DM), using topical anesthesia and dexmedetomidine (Dex) infusion. General anesthesia was given with desflurane and muscle relaxant. “Opioid-free anesthesia,” wherein use of systemic, neuraxial, or intracavitary opioids is completely eliminated, was maintained with Dex infusion for sedation and analgesia. Reversal of anesthesia was done in Fowler’s position (FP), and after extubation, nasopharyngeal airway connected to high-flow oxygen (10 L/min) via tubing was used, which facilitated spontaneous breathing, maintaining oxygen saturation and uneventful recovery. Postoperatively, intravenous paracetamol alone was adequate for effective pain relief. The patient remained hemodynamically stable throughout the perioperative period. This case underscores the benefits of “opioid-free anesthesia” using intraoperative Dex infusion and efficacious use of nasopharyngeal airway in FP postoperatively, avoiding requirement of ventilator, in supermorbidly obese patients, reducing CREs and optimizing postoperative outcomes.

Postoperative residual curarisation in geriatric patients: a prospective, observational cohort study.

To evaluate the occurrence and potential risk factors of residual curarisation after surgery and the subsequent acute respiratory events in elderly patients. The prospective, cohort study was conducted at Ankara City Hospital from July to December 2021, and comprised data of geriatric patients undergoing elective surgery under general anaesthesia using moderate-acting nondepolarising muscle relaxants. Postoperative acute respiratory events in the post-anaesthesia care unit were subsequently noted. Data was analysed using SPSS 25. Of the 185 patients aged >65 years evaluated, 174(94%) were included; 88(50.6%) females and 86(49.4%) males. The incidence of residual curarisation was in 6(3.4%) patients. Postoperative residual curarisation was significantly associated with smooth recovery process (p<0.05). The recovery was associated with intraoperative bleeding, total dose of neuromuscular blocker, and the length of time from the last dose of neuromuscular blocker to antagonist administration (p<0.05). Postoperative critical respiratory events were more common in patients with postoperative residual curarisation (p< 0.001). The length of stay in post-anaesthesia care unit was 1.57 times longer in such patients (p=0.001). Postoperative residual curarisation increased length of hospital stay and respiratory complications.

Use of a combination of diaphragmatic ultrasound and muscle relaxation monitoring in predicting post-extubation adverse respiratory events among elderly patients in an anesthesia intensive care unit

ObjectiveThe purpose of this study was to examine the feasibility of using a combination of diaphragmatic ultrasound and muscle relaxation monitoring in predicting adverse respiratory events after extubation among elderly patients in an anesthetic intensive care unit (AICU).MethodsThe study participants were 120 elderly patients who were in the AICU after laparoscopic radical resection for colorectal cancer. Based on whether there were critical respiratory events (CREs) after extubation, they were divided into the adverse event group and the non-adverse event group. We used logistic regression to identify factors influencing the occurrence of CREs post-extubation in elderly patients. Using the receiver operating characteristic (ROC) curve, we analyzed the value of each indicator in predicting CREs post-extubation.ResultsWe included 109 patients in the final analysis. In the adverse event group (n = 19), the age, proportion of females, and proportion of preoperative respiratory diseases were higher than in the non-adverse event group (n = 90). The muscle relaxation value, quiet breathing diaphragmatic excursion during extubation (DE-QB), deep breathing diaphragmatic excursion during extubation (DE-DB), and deep breathing diaphragmatic thickening fraction during extubation (DTF-DB) of patients in the adverse event group were significantly lower than those in the non-adverse event group (P < 0.05). Using binary logistic regression analysis, we identified muscle relaxation value, DE-DB, and DTF-DB during extubation as significant predictors of CREs post-extubation in elderly patients (P < 0.05). The area under the curve (AUC) of the combination of the muscle relaxation value, DE-DB, and DTF-DB during extubation for predicting CREs after extubation in elderly patients was 0.949, which was higher than that of any single indicator.ConclusionThe combination of diaphragmatic ultrasound and muscle relaxation monitoring was more accurate in predicting CREs post-extubation among elderly patients in the AICU.

Required dose of sugammadex or neostigmine for reversal of vecuronium-induced shallow residual neuromuscular block at a train-of-four ratio of 0.3.

Residual shallow neuromuscular block (NMB) is potentially harmful and contributes to critical respiratory events. Evidence for the optimal dose of sugammadex required to reverse vecuronium‐induced shallow NMB is scarce. The aims of the present study were to find suitable doses of sugammadex and neostigmine to reverse a residual vecuronium‐induced NMB from a time of flight (TOF) ratio of 0.3–0.9 and evaluate their safety and efficacy. In total, 121 patients aged 18–65 years were randomly assigned to 11 groups to receive placebo, sugammadex (doses of 0.125, 0.25, 0.5, 1.0, or 2.0 mg/kg), or neostigmine (doses of 10, 25, 40, 55, or 70 μg/kg). The reversal time of sugammadex and neostigmine to antagonize a vecuronium‐induced shallow residual NMB (i.e., TOF ratio of 0.3) and related adverse reactions were recorded. Several statistical models were tested to find an appropriate statistical model to explore the suitable doses of sugammadex and neostigmine required to reverse a residual vecuronium‐induced NMB. Based on a monoexponential model with the response variable on a logarithmic scale, sugammadex 0.56 mg/kg may be sufficient to reverse vecuronium‐induced shallow residual NMB at a TOF ratio of 0.3 under anesthesia maintained with propofol. Neostigmine may not provide prompt and satisfactory antagonism as sugammadex, even in shallow NMB.

The association between residual neuromuscular blockade (RNMB) and critical respiratory events: a prospective cohort study

BackgroundInadequate neuromuscular recovery might impair pulmonary function among adult patients who undergo general anaesthesia and might thus contribute to critical respiratory events in the post-anaesthesia care unit (PACU). The pilot study aims to understand the baseline incidence of residual neuromuscular blockade (RNMB) and postoperative critical respiratory events (CREs), which are described in a modified Murphy’s criteria in the PACU.MethodThis is a prospective cohort study from January to March 2017 from a tertiary hospital in Saudi Arabia with thirty adult patients over 18 years old scheduled for elective surgery under general anaesthesia with neuromuscular blocking drugs (NMBDs) who were enrolled in the study. The Mann-Whitney U tests, chi-square tests and independent-samples T tests were used. The train-of-four (TOF) ratios were measured upon arrival in the PACU by using acceleromyography with TOF-Scan. Subjects’ demographics, perioperative data and the occurrence of postoperative CREs in the PACU were recorded.ResultsTwenty-six (86.7%) patients out of thirty in the study have received rocuronium as NMBDs whilst neostigmine as a reversal drug with only 23 (76.7%). The incidence of RNMB (TOF ratio < 0.9) was in 16 patients (53.3%). The incidence of RNMB was significantly higher in female patients (p = 0.033), in patients who had not undergone quantitative neuromuscular monitoring before extubation (p = 0.046) and in patients with a shorter duration of surgery (p = 0.001). Postoperative CREs occurred in twenty patients (66.7%), and there were significantly more of these CREs among patients with RNMB (p = 0.001). In addition, a statistically significant difference was observed in the occurrence of CREs according to body mass index (p = 0.047).ConclusionThis research showed that RNMB is a significant contributing factor to the development of critical respiratory events during PACU stay. Therefore, routine quantitative neuromuscular monitoring is recommended to reduce the incidence of RNMB.

Development of the University Postoperative Obstructive Sleep Apnea Protocol (UPOP)

PurposeThe purpose of this project was to retrospectively analyze medical records to determine the relationship between surgical patients with obstructive sleep apnea (OSA) risk factors and the occurrence of a critical respiratory event (CRE) in the postanesthesia care unit (PACU), and to subsequently develop a protocol for postoperative care. Although OSA is prevalent among the surgical population, research has primarily focused on preoperative identification and tailored perioperative care with limited application of standardized postoperative OSA management. DesignSurgical charts were retrospectively reviewed between April 1, 2019 and June 31, 2019. Medical records were reviewed to identify surgical patients who had a diagnosis of OSA or two or more OSA risk factors. For patients who met initial inclusion, PACU charts were reviewed for the occurrence of a CRE while in PACU. Data analysis involved use of both Microsoft Excel 2011 and IBM SPSS Statistics Base, version 26. MethodsMedical records were reviewed to identify patients in PACU who had two or more documented OSA risk factors (body mass index >35, snoring, alcohol use, diabetes mellitus [DM], hypertension [HTN], or male) or a diagnosis of OSA (n = 1,361). This sample was further refined to determine the patients who had a CRE (oxygen saturation less than 92%; respiratory rate less than 10, Modified Aldrete Respiratory Score of 1 and/or lesser) while in the PACU (n = 200). FindingsThere was a statistically significant relationship between one CRE in the PACU and a pre-existing diagnosis of HTN, DM, snoring, alcohol use, and male gender (P < .001 for each variable). There was a statistically significant difference in body mass index between patients who experienced a CRE and those who did not (P = .004). HTN and DM (n = 16) were associated with the highest occurrence of a CRE. ConclusionsThe University Postoperative Obstructive Sleep Apnea Protocol was designed based on results and current evidence-based practice. Development of a postoperative OSA protocol will positively impact patient outcomes and may reduce health care expenditures. Next steps include protocol implementation and analysis.

The Effect of Sugammadex on Respiratory Functions in Bariatric Surgery

Objective: Bariatric surgeries increased in the last decades likewise obesity. The need for high doses of neuromuscular blocking agents in these surgeries may cause residual paralysis and also critical respiratory events and late complications such as hypoxemia, pneumonia, atelectasis, and the possibility of reintubation. The purpose of this study to evaluate the effect of sugammadex on respiratory parameters. Materials and method: 62 patients are included the study and they were assigned to one of the two groups randomly. LSG operation was performed on all the patients based on standard anesthesia management. In Group S (n=31), Sugammadex 2 mg/kg was administered for the reversal of rocuronium. In Group N (n=31), Neostigmine 0.05 mg/kg was administered together with atropine 0.02 mg/kg for the reversal of rocuronium. Extubation duration, Aldrete scores at 5, 10, and 15 minutes after extubation, PACU duration, FEV1 values of RFT, ABG values, mobilization time were analyzed. Results: In group S, patients have higher PO2 and lower PCO2 levels, shorter mobilization times, and an Aldrete score of 15 sooner, and moreover, they occupy the operating room and PACU to a lesser extent but FEV1 values did not differ between groups. Conclusion: In conclusion, sugammadex allows a safe and rapid recovery from deep rocuronium-induced neuromuscular blockade after LSG surgery.

Reversal of rocuronium neuromuscular blockade in elderly patients undergoing elective open abdominal surgery: comparative study of sugammadex versus neostigmine

Objectives To evaluate neuromuscular recovery in elderly patients assigned for open abdominal surgery using sugammadex (Sx) versus neostigmine–atropine (NA) combination. Patients and methods A total of 142 male patients were randomly allocated into two equal groups: group NA received neostigmine (50 μg/kg) and group Sx received Sx (2 mg/kg). Neuromuscular function was monitored according to changes of the train-of-four (TOF) using the TOF-Watch-SX; at TOF0, rocuronium (0.5 mg/kg) was given and trachea was intubated. During surgery, at TOF25, a dose of one-quarter of the initial dose of rocuronium was given. At the end of surgery, when TOF25 was reached, the assigned reversal drug was administered, and patients were extubated at TOF90. The study outcomes included TOF25–90 interval (time since injection of the reversal drug till recovery to TOF ratio of 0.9), the recovery period (time since anesthetic gases were stopped till modified Aldrete Recovery Score was ≥9), and the development of critical respiratory events (CREs). Results The percentage of patients whose had short TOF25–90 interval was significantly higher with Sx than neostigmine. TOF25–90 interval with Sx (3.3±1.6 min) was significantly shorter compared with neostigmine (9.9±2 min). Patients who received Sx reached modified Aldrete Recovery Score more than or equal to 9 significantly earlier than those who received neostigmine. Thirteen (9.2%) patients developed postoperativeCRE, 10 (14.1%) in group NA versus three (4.2%) patients in group Sx, with significantly lower percentages in Sx than neostigmine groups. Only two patients in NA group required re-intubation for residual neuromuscular blockade (NMB) and were maintained on oxygen but failed to reach TOF90, both patients responded well to Sx (2 mg/kg) injection and reached to TOF90 after 2 and 3 min, respectively. Conclusion Reversal of NMB using Sx is an effective, satisfactory, and safe modality versus neostigmine with significantly short TOF25–90 interval and lower frequency of CRE. Sx effectively resolved residual NMB after failure or delayed recovery after neostigmine injection in elderly patients who underwent open abdominal surgery.

Sugammadex versus neostigmine in reversal of rocuronium-induced neuromuscular block in obese patients

Background Obese patients are especially susceptible to critical respiratory events in the postoperative period, including airway obstruction, hypoventilation, hypercapnia, hypoxia, and postoperative residual curarization (PORC); hence, rapid and complete reversal of neuromuscular blockade (NMB) is desirable at the end of surgery. Objective This study aimed to compare between the effect of sugammadex and neostigmine on recovery time, PORC and estimate postoperative complications at the postanaesthetic care unit in obese patients. Patients and methods Seventy obese patients, BMI greater than 35 kg/m2 American Society of Anaesthesiologist class I–II, scheduled for a surgical procedure under general anesthesia were included in this study. Patients received rocuronium for muscle relaxation, and, at the end of the surgery, patients were divided randomly into two groups: one group received sugammadex 2 mg/kg of ideal body weight (group S) and the other group received neostigmine 0.05 mg/kg plus atropine 0.01 mg/kg of ideal body weight (group N) to reverse the NMB. NMB was monitored using train-of-four (TOF). At reappearance of the second twitch (T2) of TOF, patients received the study drugs, and time to reach (TOF) greater than 0.9, was recorded. All patients were observed at the postanaesthetic care unit for one hour for PORC and haemodynamic value (heart rate, mean arterial pressure, and SpO2) by a blinded investigator. Results At the end of surgery extubation was done when reached a train-of-four (TOF %) score of 2, patients at this percentage received the study drugs the neuromuscular function was recorded and time to achieve 90% of TOF (safe extubation) was measured. Train-of-four (TOF%) is the ratio of the fourth muscle response to the first one. It meaning median time to recovery of the T4:T1 ratio to 0.9. Conclusion Administration of sugammadex provides fast recovery of neuromuscular function than neostigmine following NMB by rocuronium and prevents PORC in obese patients.

Airway management in paediatric anaesthesia in Europe—insights from APRICOT (Anaesthesia Practice In Children Observational Trial): a prospective multicentre observational study in 261 hospitals in Europe

BackgroundCritical respiratory events are common in children in the peri-anaesthetic period and are caused by airway and ventilation management difficulties. We aimed to analyse current European paediatric airway management practices and identify the incidence and potential consequences of difficult airway management. MethodsWe performed a secondary analysis of airway and ventilation management details of the European multicentre observational trial (Anaesthesia PRactice in Children Observational Trial, APRICOT) of children from birth to 15 yr of age. The primary endpoint was the incidence of difficult airway management. Secondary endpoints were the associations between difficult airway management, known pre-existing respiratory risk factors, and the occurrence of critical respiratory events. ResultsDetails for 31 024 anaesthetic procedures were available for analysis. Three or more tracheal intubation attempts were necessary in 120 children (0.9%) and in 40 children (0.4%) for supraglottic airways insertions. The incidence (95% confidence interval) for failed tracheal intubation and failed supraglottic airway insertions was 8/10 000 (0.08%; 0.03–0.13%) and 8.2/10 000 (0.08%; 0.03–0.14%) children, respectively. Difficulties in securing the airway increased the risk for a critical respiratory event for tracheal tube (2.1; 1.3–3.4) and supraglottic airway (4.3; 1.9–9.9) placement. History of pre-existing respiratory risk factors was significantly associated with critical respiratory events independently of the airway device used. ConclusionsAirway management practices vary widely across Europe. Multiple airway device insertion attempts and pre-existing respiratory risk factors increase the likelihood of critical respiratory events in children and require further stratification during preoperative assessment and planning. This study highlights areas where education, research, and training may improve perioperative care. Clinical trial registrationNCT01878760.

Feasibility of Automated Propofol Sedation for Transcatheter Aortic Valve Implantation: A Pilot Study.

Recently, several trials have shown that closed-loop sedation is feasible. No study has used automated sedation in extremely frail patients, such as those scheduled for transcatheter aortic valve implantation (TAVI). We developed and tested a novel automated sedation system for this kind of population and surgery. The system integrates a decision support system that detects respiratory and hemodynamic events via smart alarms, which provide pertinent/related clinical suggestions and treatment options. The main objective was the feasibility of closed-loop sedation, defined as successful automated sedation without manual override. Secondary qualitative observations were clinical and controller performance. Twenty patients scheduled for elective TAVI were enrolled. Sedation was administered via a closed-loop delivery system designed for propofol. The clinical performance of sedation was the efficacy to maintain a bispectral index (BIS) of 65. To evaluate the sedation performance, BIS values were stratified into 4 categories: excellent, very good, good, and inadequate sedation control, defined as BIS values within 10%, ranging from 11% to 20%, ranging from 21% to 30%, or >30% from the target value, respectively. The controller performance was calculated using Varvel parameters. Critical respiratory and hemodynamic events were documented. The former was defined as peripheral oxygen saturation <92% and/or respiratory rate <8/min, whereas the latter was considered a mean arterial pressure <60 mm Hg and/or heart rate <40 bpm. Automated sedation was successful in 19 patients undergoing TAVI. One patient was excluded from the final analysis because of conversion to general anesthesia. The secondary observations revealed that the clinical performance allowed an excellent to good control during 69% (99% confidence interval, 53%-77%; interquartile range, 59%-79%) of the sedation time. Fifteen patients presented critical respiratory episodes, with a median of 3 events per hour of sedation. Six patients presented critical hemodynamic episodes, with a median of 2 events per hour of procedure. The automated closed-loop sedation system tested could be used successfully for patients scheduled for a TAVI procedure. The results showed a satisfactory clinical performance of sedation control.

Incidence of postoperative residual paralysis in a nigerian teaching hospital.

Postoperative residual paralysis (PORP) is a known risk factor after general anesthesia (GA) for critical respiratory events and increased postoperative morbidity. PORP is defined as a train-of-four ratio (TOFR) of <0.9 using acceleromyography (AMG). TOFR <0.9 has been associated with increased risk of aspiration, obstruction of the upper airway and an impaired hypoxic ventilatory response. The aim of this study was to determine the incidence of PORP, associated factors related with its occurrence and critical respiratory events in the postanesthesia recovery room (PAR) at our institution. Forty-one adult patients were scheduled for elective surgeries requiring GA with the use of at least 1 dose of a nondepolarizing neuromuscular blocking drug (NMBD). An independent anesthetist quantitatively measured TOFR of recruited patients postoperatively in the recovery room using the TOF-watch SX acceleromyograph (Organon Teknika) 5 min after arrival. The incidence of PORP was 75.6% (n = 31), with severe PORP (TOFR <0.7) seen in 41.5% (n = 17) of patients. Median time to full recovery in the PAR was 33 min (range 5-164 min). There was no statistical difference in the incidence of PORP related to the choice of NMBD (P = 0.186) or duration of surgery (P = 0.175). No respiratory complications or events were observed in patients with residual blockade. The incidence of PORP is quite high and undetected in our environment. Quantitative monitoring for residual paralysis is advocated as part of routine monitoring with the use of NMBDs for improved patient safety.

Do we really need sugammadex as an antagonist of muscle relaxants in anesthesia?

Sugammadex is a selective relaxant-binding agent that is designed to encapsulate rocuronium and chemically similar steroidal muscle relaxants such as vecuronium. This review summarizes recent information on the use of sugammadex in clinical practice. The main advantages of sugammadex when compared with conventional anticholinesterase agents are a much faster recovery time and its unique ability to reverse rapidly and efficiently, for the first time, deep levels of neuromuscular blockade. However, there is paucity of evidence-based studies on the benefit of deep neuromuscular block, and then routine administration of sugammadex to reverse any level of block, for example, during laparoscopic surgery. It appears that reduction of costs depends mainly on organizational factors. Finally it must be remembered that sugammadex only works with steroidal nondepolarizing muscle relaxants; therefore neostigmine should not be withdrawn because it is the only reversal agent effective against atracurium or cisatracurium. Sugammadex offers a significantly faster and more predictable recovery profile than neostigmine. It is now possible to reverse rapidly and efficiently any level of neuromuscular blockade and to avoid the risk of adverse events because of residual paralysis such as critical respiratory events during recovery from anesthesia.

The Effect of Quantitative Neuromuscular Monitoring on the Incidence of Residual Neuromuscular Blockade and Clinical Outcomes

Neuromuscular blocking agents (NMBAs) are useful perioperative medications. Despite this utility, their administration is associated with increased morbidity due to residual neuromuscular blockade. Clinical testing prior to tracheal extubation is subjective, dependent on the patient’s cooperation, and not predictive of adequate respiratory function to prevent the occurrence of postoperative critical respiratory events. The use of peripheral nerve stimulators may improve detection of residual weakness; however, this technique does not reliably detect residual paralysis, as it requires the subjective (and imperfect) assessment of fade in response to train-of-four (TOF) stimulation. Quantitative neuromuscular monitoring can be accomplished through a variety of modalities and remains as the most effective and reproducible method of detecting residual paralysis after NMBA administration. In this review, we will discuss the various techniques that are used clinically to assess depth of block and adequacy of reversal, with a focus on quantitative (objective) neuromuscular monitoring.

Ritonavir Use in Human Immunodeficiency Virus–Positive Surgical Patients Is Not Associated with an Increase in Postoperative Critical Respiratory Events

ABSTRACTThis study evaluated whether highly active antiretroviral therapy for human immunodeficiency virus (HIV) including ritonavir is independently associated with increased critical respiratory events after general anesthesia with opioid analgesia. The impact of ritonavir on hepatic microsomal enzymes was considered due to the effect of these enzymes on opioid metabolism. Medical records of over 1900 patients were reviewed, and those of 941 patients met inclusion criteria and were analyzed. Chronic treatment with ritonavir was not associated with critical respiratory events in HIV-positive patients.

Risk predictors of opioid-induced critical respiratory events in children: naloxone use as a quality measure of opioid safety.

Opioid-induced respiratory depression (OIRD) is a life-threatening complication of opioid therapy in children. Naloxone administration triggered by OIRD has been used to monitor safety of opioid therapy in adults. We used this trigger as a quality measure of opioid safety in hospitalized children to identify risk predictors of OIRD. We retrospectively reviewed medical records of 38 patients identified from the hospital risk management database as requiring naloxone for critical respiratory events between January 2010 and June 2012 for demographics, comorbidities, surgery, naloxone event details, and outcomes. These data were compared with baseline prevalence in contemporary patients followed by pain service, who did not receive naloxone, to calculate unadjusted odds ratios. Thematic classification of preventable events was undertaken based on analysis of each event. The incidence of naloxone use among hospital inpatients, who received opioids at-least once, was 0.06% compared with 0.23% for patients on the pain service. A majority of naloxone events occurred in postoperative patients (n = 27/38, 71.1%) within the first 24 hours of surgery (n = 20/27, 75.1%) and in the critical care unit (50%). Patients undergoing airway surgeries had higher risk for OIRD (P = 0.01). Patient risk factors for naloxone use included age <1 year (P < 0.001), obstructive sleep apnea (P < 0.001), obesity (P = 0.019), being underweight (P < 0.0001), prematurity (P < 0.001), and developmental delay (P < 0.001). Majority of events (87%) were found to be preventable, which were classified into six main themes based on type of event. OIRD is an important, albeit mostly preventable, complication of opioid therapy in children. Naloxone use can be used as a measure to track opioid safety in children, identify contributing factors, and formulate preventive strategies to reduce the risk for OIRD.

Can short-term heart rate variability be used to monitor fentanyl-midazolam induced changes in ANS preceding respiratory depression?

Opioids have an occasional but high-risk side effect of respiratory depression. The detection of critical respiratory depression usually occurs after the event. Earlier detection would be beneficial in preventing increased morbidity and mortality of 0.01 % patients receiving analgesic opioids. Airway patency during inspiration requires vagal modulation. Regulation of the cardiovascular and respiratory centres may be coupled with a central mechanism that is indirectly measurable with heart rate variability (HRV). While opioids tend to increase parasympathetic tone, a decrease in airway stability could be due to a decrease in respiratory parasympathetic activity. Sympathetic arousal generated by apneic events may separately be recognised with short-term HRV. This pilot observational study examined the dynamic sympathovagal changes during fentanyl-midazolam induced respiratory depression on 10 subjects scheduled for minor surgery. A selection of HRV indices, able to work over sub-minute periods on non-stationary signals, were applied including a range of less common indices. Three analyses tested the effects: post-fentanyl, preceding the first central depression, and preceding obstruction of the upper airway. Statistical significance was assessed with overlap of bootstrap percentile confidence intervals for the median. A decrease in total variability, Lomb Total using the Lomb-Scargle method, is a positive finding for short-term HRV use in this study. No significant change before critical respiratory events was observed in traditional, spectral power, respiratory or other indices. One index, PolVar20, indicated a burst of sympathetic activity preceding respiratory depression similar to sleep apnoea arousals that restore airway patency. Before its usefulness in early detection of airway tone can be determined, PolVar20 requires further work: a statistical method for highly skewed distributions, auto adjustment for baseline variability, and detecting a range of sympathetic responses to apnea.

Pesquisa de curarização residual no pós‐operatório, eventos respiratórios agudos e abordagem de anestesiologistas

Background and objectivesResidual paralysis following the use of neuromuscular blocking drugs (NMBDs) without neuromuscular monitoring remains a clinical problem, even when NMBDs are used. This study surveys postoperative residual curarization and critical respiratory events in the recovery room, as well as the clinical approach to PORC of anesthesiologists in our institution. MethodsThis observational study included 415 patients who received general anesthesia with intermediate‐acting NMBDs. Anesthesia was maintained by non‐participating anesthesiologists who were blinded to the study. Neuromuscular monitoring was performed upon arrival in the recovery room. A CRE was defined as requiring airway support, peripheral oxygen saturation <90% and 90–93% despite receiving 3L/min nasal O2, respiratory rate >20breaths/min, accessory muscle usage, difficulty with swallowing or speaking, and requiring reintubation. The clinical approach of our anesthesiologists toward reversal agents was examined using an 8‐question mini‐survey shortly after the study. ResultsThe incidence of PORC was 43% (n=179) for TOFR <0.9, and 15% (n=61) for TOFR <0.7. The incidence of TOFR <0.9 was significantly higher in women, in those with ASA physical status 3, and with anesthesia of short duration (p<0.05). In addition, 66% (n=272) of the 415 patients arriving at the recovery room had received neostigmine. A TOFR <0.9 was found in 46% (n=126) of the patients receiving neostigmine. ConclusionsWhen routine objective neuromuscular monitoring is not available, PORC remains a clinical problem despite the use of NMBDs. The timing and optimal antagonism of the neuromuscular blockade, and routine objective neuromuscular monitoring is recommended to enhance patient safety.

Survey of postoperative residual curarization, acute respiratory events and approach of anesthesiologists

Background and objectivesresidual paralysis following the use of neuromuscular blocking drugs (NMBDs) without neuromuscular monitoring remains a clinical problem, even when NMBDs are used. This study surveys postoperative residual curarization and critical respiratory events in the recovery room, as well as the clinical approach to PORC of anesthesiologists in our institution. MethodsThis observational study included 415 patients who received general anesthesia with intermediate-acting NMBDs. Anesthesia was maintained by non-participating anesthesiologists who were blinded to the study. Neuromuscular monitoring was performed upon arrival in the recovery room. A CRE was defined as requiring airway support, peripheral oxygen saturation <90% and 90–93% despite receiving 3L/min nasal O2, respiratory rate >20breaths/min, accessory muscle usage, difficulty with swallowing or speaking, and requiring reintubation. The clinical approach of our anesthesiologists toward reversal agents was examined using an 8-question mini-survey shortly after the study. ResultsThe incidence of PORC was 43% (n=179) for TOFR <0.9, and 15% (n=61) for TOFR <0.7. The incidence of TOFR <0.9 was significantly higher in women, in those with ASA physical status 3, and with anesthesia of short duration (p<0.05). In addition, 66% (n=272) of the 415 patients arriving at the recovery room had received neostigmine. A TOFR <0.9 was found in 46% (n=126) of the patients receiving neostigmine. ConclusionsWhen routine objective neuromuscular monitoring is not available, PORC remains a clinical problem despite the use of NMBDs. The timing and optimal antagonism of the neuromuscular blockade, and routine objective neuromuscular monitoring is recommended to enhance patient safety.