Anaesthetic-related recovery room complications

Effect of cuff inflation with lidocaine, saline, and air on tracheal tube cuff pressure during laparoscopic resection of colorectal neoplasms: a randomized clinical trial

BACKGROUND

Tracheal tube cuff pressure will increase after pneumoperitoneum when the cuff is inflated with air, high pressure can cause tracheal mucosal damage. This prospective trial aimed to assess if inflating with normal saline or lidocaine can prevent increase of tracheal tube cuff pressure and tracheal mucosal damage in laparoscopic surgeries with general anesthesia. Whether changes of tracheal tube cuff transverse diameter (CD) can predict changes of tracheal tube cuff pressure.

METHODS

Ninety patients scheduled for laparoscopic resection of colorectal neoplasms under general anesthesia were randomly assigned to groups air (A), saline (S) or lidocaine (L). Endotracheal tube cuff was inflated with room-temperature air in group A (n = 30), normal saline in group S (n = 30), 2% lidocaine hydrochloride injection in group L (n = 30). After intubation, tracheal tube cuff pressure was monitored by a calibrated pressure transducers, cuff pressure was adjusted to 25 cmH2O (T0.5). Tracheal tube cuff pressure at 15 min after pneumoperitoneum (T1) and 15 min after exsufflation (T2) were accessed. CD were measured by ultrasound at T0.5 and T1, the ability of ΔCD (T1-0.5) to predict cuff pressure was accessed. Tracheal mucous injury at the end of surgery were also recorded.

RESULTS

Tracheal tube cuff pressure had no significant difference among the three groups at T1 and T2. ΔCD had prediction value (AUC: 0.92 [95% CI: 0.81-1.02]; sensitivity: 0.99; specificity: 0.82) for cuff pressure. Tracheal mucous injury at the end of surgery were 0 (0, 1.0) in group A, 0 (0, 1.0) in group S, 0 (0, 0) in group L (p = 0.02, group L was lower than group A and S, p = 0.03 and p = 0.04).

CONCLUSIONS

Compared to inflation with air, normal saline and 2% lidocaine cannot ameliorate the increase of tracheal tube cuff pressure during the pneumoperitoneum period under general anesthesia, but lidocaine can decrease postoperative tracheal mucosa injury. ΔCD measured by ultrasound is a predictor for changes of tracheal tube cuff pressure.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, identifier: ChiCTR2100054089, Date: 08/12/2021.

Modulating anesthetic emergence with pathway-selective dopamine signaling

PURPOSE OF REVIEW

To summarize the recent preclinical findings investigating dopaminergic circuits for their involvement in reversing anesthetic-induced unconsciousness.

RECENT FINDINGS

The release of dopamine from the ventral tegmental area onto dopamine D1 receptor-expressing neurons in the nucleus accumbens promotes emergence following general anesthesia. Two relevant targets of dopamine D1 receptor-expressing neurons in the nucleus accumbens include the lateral hypothalamus and ventral pallidum. Activating mesocortical dopaminergic projections from the ventral tegmental area to the prelimbic cortex has also been shown to hasten emergence from general anesthesia. In contrast, the nigrostriatal dopamine pathway is not involved in regulating anesthetic emergence. The role of the tuberoinfundibular endocrine dopamine pathway remains to be tested; however, recent studies have identified an important function of neuroendocrine signaling on modulating general anesthesia.

SUMMARY

Potential avenues for accelerating anesthetic emergence may be found through targeting specific arousal-promoting pathways in the brain. Accumulating evidence from rodent studies manipulating cell type- and circuit-specific signaling pathways have identified dopamine as a potent modulator of general anesthesia. Specifically, dopamine signaling along the mesolimbic and mesocortical pathways plays a fundamental role in regulating consciousness.

[Central anticholinergic, neuroleptic malignant and serotonin syndromes]

Impaired consciousness is a frequent phenomenon after general anesthesia. In addition to the classical causes (e.g., overhang of sedatives), an impairment of consciousness can also be an adverse side effect of drugs. Many drugs used in anesthesia can trigger these symptoms. Alkaloids, such as atropine can trigger a central anticholinergic syndrome, opioids can promote the occurrence of serotonin syndrome and the administration of a neuroleptic can lead to neuroleptic malignant syndrome. These three syndromes are difficult to diagnose due to the individually very heterogeneous symptoms. Mutual symptoms, such as impaired consciousness, tachycardia, hypertension and fever further complicate the differentiation between the syndromes; however, more individual symptoms, such as sweating, muscle tension or bowl sounds can be helpful in distinguishing these syndromes. The time from the trigger event can also help to differentiate the syndromes. The central anticholinergic syndrome is the fastest to appear, usually taking just a few of hours from trigger to clinical signs, serotonin syndrome takes several hours up to 1 day to show and neuroleptic malignant syndrome usually takes days. The clinical symptoms can range from mild to life-threatening. Generally, mild cases are treated with discontinuation of the trigger and extended observation. More severe cases can require specific antidotes. The specific treatment recommended for central anticholinergic syndrome is physostigmine with an initial dose of 2 mg (0.04 mg/kg body weight, BW) administered over 5 min. For serotonin syndrome an initial dose of 12 mg cyproheptadine followed by 2 mg every 2 h is recommended (maximum 32 mg/day or 0.5 mg/kgBW day-1) but this medication is only available in Germany as an oral formulation. For neuroleptic malignant syndrome 25-120 mg dantrolene (1-2.5 mg/kgBW maximum 10 mg/kgBW day-1) is the recommended treatment.

Development of prediction models to estimate extubation time and midterm recovery time of ophthalmic patients undergoing general anesthesia: a cross-sectional study

BACKGROUND

To develop prediction models for extubation time and midterm recovery time estimation in ophthalmic patients who underwent general anesthesia.

METHODS

Totally 1824 ophthalmic patients who received general anesthesia at Joint Shantou International Eye Center were included. They were divided into a training dataset of 1276 samples, a validation dataset of 274 samples and a check dataset of 274 samples. Up to 85 to 87 related factors were collected for extubation time and midterm recovery time analysis, respectively, including patient factors, anesthetic factors, surgery factors and laboratory examination results. First, multiple linear regression was used for predictor selection. Second, different methods were used to develop predictive models for extubation time and midterm recovery time respectively. Finally, the models' generalization abilities were evaluated using a same check dataset with MSE, RMSE, MAE, MAPE, R-Squared and CCC.

RESULTS

The fuzzy neural network achieved the highest R-Squared of 0.956 for extubation time prediction and 0.885 for midterm recovery time, and the RMSE value was 6.637 and 9.285, respectively.

CONCLUSION

The fuzzy neural network developed in this study had good generalization performance in predicting both extubation time and midterm recovery time of ophthalmic patients undergoing general anesthesia.

TRIAL REGISTRATION

This study is prospectively registered in the Chinese Clinical Trial Registry, registration number: CHiCRT2000036416, registration date: August 23, 2020.

The efficacy of nalmefene on anesthetic recovery of patients: a study protocol for a multicenter randomized controlled trial

INTRODUCTION

So far, the recovery quality after general anesthesia is still unsatisfied. Nalmefene is a drug to treat opioid overdose and reverse opioid actions. We aim to investigate the efficacy of nalmefene on optimizing the recovery quality of patients after general anesthesia.

METHODS

It is a prospective, placebo-controlled, two-arm parallel groups, multicentre, double-blind, randomized (PPPMDR) clinical trial. The participants (n = 520) will be randomly assigned into two groups. Each patient will receive either: a single dose of nalmefene 0.25 µg/kg in the intervention group, or the same volume of 0.9% NaCl solution in the control group at the end of the surgery. The primary outcome will be the time interval between the end of anaesthesia and recovery endpoints achieved (Aldrete recovery score ≥ 9) in post-anesthesia care unit (PACU). The other variables are the time interval from the end of operation to extubation; Richmond Agitation Sedation Scale (RASS) score at extubation; the time at Montreal Cognitive Assessment Scale (MoCA) orientation score ≥ 5; visual analog scale (VAS) score and adverse effects including postoperative nausea and vomiting (PONV), and pruritus in PACU and 24 h postoperatively.

ANALYSIS

This trial aims to study whether small dose of nalmefene can shorten the time from the end of surgery to Aldrete score ≥ 9 and improve opioid-induced side effects.This trial focuses on providing the reliable clinical evidence for satisfactory quality of recovery.

ETHICS AND DISSEMINATION

This clinical trial has been approved and supported by the ethics committee of the Renji Hospital, Shanghai Jiaotong University, School of Medicine (KY2020-150); Shanghai Tongren Hospital (2021-030-01);The First Affiliated Hospital of Guangxi Medical University (2021-032); and The First Affiliated Hospital of Zhengzhou University(2021-KY-0495-003). Analysis of the study results will be submitted to a peer-reviewed journal for publication.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04713358, Registered on September 23, 2021.

Effects of continuous and slow tracheal tube cuff deflation on cough reflex during extubation in noncardiac surgery patients: a randomised clinical trial

BACKGROUND

The incidence of cough reflex during extubation is 76%. Cough reflex causes severe hemodynamic fluctuations and airway complications. This prospective trial investigated the potential effects of tracheal tube cuff deflation on cough reflex during extubation.

METHODS

One hundred and twenty-six patients scheduled for operations within 3 h under general anaesthesia with orotracheal intubation were randomly assigned to one of three groups: control (C), experimental (E) or syringe (S) groups. Patients in group C underwent tracheal tube cuff deflation using a 10-ml syringe in 1 s, patients in group E underwent tracheal tube cuff deflation continuously and slowly in 5 s using a cuff pressure gauge until the pressure was zero and patients in group S underwent tracheal tube cuff deflation using a 10-ml syringe at a speed of 1 ml s^-1. The incidence and severity of cough reflexs during extubation and the incidence of postoperative airway complications within 48 h were assessed.

RESULTS

Compared with group C (60.0%), the incidence of cough reflex in group E was 9.8% (p < 0.001) and in group S was 12.5% (p < 0.001). The severity of cough reflex was graded as 2 (1-2) in group C, 1 (1-1) in group E and 1 (1-1) in group S (p < 0.001 for group comparisons). The incidence of hoarseness in group C was 0.0%, in group E was 19.5% and in group S was 5.0% (p < 0.05 for all groups, p = 0.009 between group C and E).

CONCLUSIONS

Compared with deflating a trachal tube cuff with a 10-ml syringe in 1 s, the use of a 10-ml syringe at a speed of 1 ml s^-1 or a cuff pressure guage within 5 s can both reduce the incidence of cough reflex, but deflating with a cuff pressure guage can increase the incidence of postoperative hoarseness.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, identifier: ChiCTR2100054089, Date: 08/12/2021.

The Effect of Preoperative Oral Carbohydrate on the Incidence of Complications in PACU After General Anesthesia: A Prospective Cohort Study

PURPOSE

This study aimed to investigate the effect of preoperative oral carbohydrate (POC) loading on the occurrence of complications in the postanesthesia care unit (PACU) after general anesthesia.

DESIGN

Prospective observational cohort study METHODS: Patients who were scheduled for abdominal surgery under general anesthesia at our institution were divided into the POC group and control group based on whether they drank carbohydrate solution 2 hours before surgery. POC loading of the patients was decided by the responsible surgeon. In PACU, the occurrence of postoperative complications including delayed emergence, emergence agitation, hypoxemia, hypertension, hypotension, moderate to severe postoperative pain, nausea and vomiting, hypothermia, shivering, and time to awakening, time to extubation, length of PACU stay were recorded.

FINDINGS

Data from 307 patients (n = 154 in POC group and n = 153 in control group) were included in the final analysis. Compared to the control group, POC led to a near-significant reduction in the overall incidence of complications in PACU after surgery (37.0% vs 47.7%, P = .058). The POC group had a lower incidence of hypothermia and shorter mean time to awakening when compared to control group (6.5% vs 16.3%, P = .007 and 19 min vs 21 min, P = .007, respectively). No statistical differences were detected in other outcome measurements between the POC group and the control group.

CONCLUSIONS

POC is associated with a trend to decrease the overall incidence of complications during recovery period after general anesthesia in patients who underwent abdominal surgery. Moreover, POC could reduce the risk of hypothermia in PACU and shorten the time to awakening.

[Central anticholinergic, neuroleptic malignant and serotonin syndromes : Important differential diagnoses in postoperative impairment of consciousness]

Impaired consciousness is a frequent phenomenon after general anesthesia. In addition to the classical causes (e.g., overhang of sedatives), an impairment of consciousness can also be an adverse side effect of drugs. Many drugs used in anesthesia can trigger these symptoms. Alkaloids, such as atropine can trigger a central anticholinergic syndrome, opioids can promote the occurrence of serotonin syndrome and the administration of a neuroleptic can lead to neuroleptic malignant syndrome. These three syndromes are difficult to diagnose due to the individually very heterogeneous symptoms. Mutual symptoms, such as impaired consciousness, tachycardia, hypertension and fever further complicate the differentiation between the syndromes; however, more individual symptoms, such as sweating, muscle tension or bowl sounds can be helpful in distinguishing these syndromes. The time from the trigger event can also help to differentiate the syndromes. The central anticholinergic syndrome is the fastest to appear, usually taking just a few of hours from trigger to clinical signs, serotonin syndrome takes several hours up to 1 day to show and neuroleptic malignant syndrome usually takes days. The clinical symptoms can range from mild to life-threatening. Generally, mild cases are treated with discontinuation of the trigger and extended observation. More severe cases can require specific antidotes. The specific treatment recommended for central anticholinergic syndrome is physostigmine with an initial dose of 2 mg (0.04 mg/kg body weight, BW) administered over 5 min. For serotonin syndrome an initial dose of 12 mg cyproheptadine followed by 2 mg every 2 h is recommended (maximum 32 mg/day or 0.5 mg/kgBW day^-1) but this medication is only available in Germany as an oral formulation. For neuroleptic malignant syndrome 25-120 mg dantrolene (1-2.5 mg/kgBW maximum 10 mg/kgBW day^-1) is the recommended treatment.

Evaluation of Complication Development in General Surgery Patients Admitted to the Post Anesthesia Care Unit

Collapse

Incidence and factors associated with post-anesthesia care unit complications in resource-limited settings: An observational study

Background and aims

Postoperative complications are frequent encounters in the patients admitted to postanesthesia care units (PACU). The main aim of this study was to assess the incidence of complications and associated factors among surgical patients admitted in limited-resource settings of the PACU.

Methods

This is an observational study of 396 surgical patients admitted to PACU. This study was conducted from February 1 to March 30, 2021, in Ethiopia. Study participants' demographics, anesthesia, and surgery-related parameters, PACU complications, and length of stay in PACU were documented. Multivariate and bivariate logistic regression analyses, the odds ratio (OR), and 95% confidence interval (CI) were calculated. p-value < 0.05 was considered as statistically significant.

Results

The incidence of complications among surgical patients admitted to PACU was 54.8%. Of these, respiratory-related complications and postoperative nausea/vomiting were the most common types of PACU complications. Being a female (adjusted odds ratio [AOR] = 2.928; 95% CI: 1.899-4.512) was significantly associated with an increased risk of developing PACU complications. Duration of anesthesia >4 h (AOR = 5.406; 95% CI: 2.418-12.088) revealed an increased risk of association with PACU complications. The occurrences of intraoperative complications (AOR = 2.238; 95% CI: 0.991-5.056) during surgery were also associated with PACU complications. Patients who develop PACU complications were strongly associated with length of PACU stay for >4 h (AOR = 2.177; 95% CI: 0.741-6.401).

Conclusion

The identified risk factors for complications in surgical patients admitted to PACU are female sex, longer duration of anesthesia, and intraoperative complications occurrences. Patients who developed complications had a long time of stay in PACU. Based on our findings, we recommend the PACU team needs to develop area-specific institutional guidelines and protocols to improve the patients' quality of care and outcomes in PACU.

Delayed Recovery After Deep Brain Stimulation Surgery for Parkinson's Disease Under General Anesthesia-Cases Report

Objective

Parkinson's disease (PD) is a neurodegenerative syndrome, and deep-brain stimulation (DBS) is an effective therapy for carefully screened patients with PD. However, delayed recovery after anesthesia, which occurs after taking prolonged general anesthesia for such patients, has been reported less frequently in literature. This report explores the possible causes of postoperative awakening delay in patients undergoing DBS surgery due to general anesthesia and provides a reference for anesthesia management of similar operations in the future.

Case Presentation

Three patients with PD elective underwent DBS surgery. The first patients demonstrated walking disability, gait deficits, unstable posture, limb stiffness, and imbalance. The second demonstrated left limb static tremor, stiffness, and bradykinesia. The third demonstrated bradykinesia, rigidity, walking deficits, and decreased facial expression. These included two males and one female with a mean patient age of 60.7 ± 6.7year, weight of 63.7 ± 11 kg, the height of 163.3 ± 7.6 cm, and preoperative American Society of Anesthesiology rating of 2.3 ± 0.6. The preoperative Glasgow Coma Scale mean score was 15. All patients completed the operation under general anesthesia (the mean anesthesia time was 5.3 ± 1.1 h). The mean operation time was 252 ± 60 min. The mean bleeding volume was 50 ml, and the urine volume was 867 ± 569 ml. However, all the patients showed unconsciousness after 95 ± 22 min after stopping the anesthetic, and the respiratory function was in good condition, but they could not cooperate with anesthesiologists and had no response to the anesthesiologist's instructions. The mean hospital stay was 17 ± 7 days. All patients were discharged uneventfully. The average number of days patients followed up postoperatively was 171 ± 28.5 days. Motor and speech were improved significantly postoperatively in three patients compared with preoperatively. Taking anti-Parkinson medication was markedly reduced. There were no complications during postoperative follow-up.

Conclusions

To prevent delayed recovery occurring after DBS surgery in Parkinson's disease, it is recommended to take scalp nerve block + general anesthesia to complete the procedure while avoiding general anesthesia.

Delayed Emergence from Anesthesia: What We Know and How We Act

The emergence from anesthesia is the stage of general anesthesia featuring the patient’s progression from the unconsciousness status to wakefulness and restoration of consciousness. This complex process has precise neurobiology which differs from that of induction. Despite the medications commonly used in anesthesia allow recovery in a few minutes, a delay in waking up from anesthesia, called delayed emergence, may occur. This phenomenon is associated with delays in the operating room, and an overall increase in costs. Together with the emergence delirium, the phenomenon represents a manifestation of inadequate emergence. Nevertheless, in delayed emergence, the transition from unconsciousness to complete wakefulness usually occurs along a normal trajectory, although slowed down. On the other hand, this awakening trajectory could proceed abnormally, possibly culminating in the manifestation of emergence delirium. Clinically, delayed emergence often represents a challenge for clinicians who must make an accurate diagnosis of the underlying cause to quickly establish appropriate therapy. This paper aimed at presenting an update on the phenomenon, analyzing its causes. Diagnostic and therapeutic strategies are addressed. Finally, therapeutic perspectives on the “active awakening” are reported.

Remote Surveillance Technologies: Realizing the Aim of Right Patient, Right Data, Right Time

The convergence of multiple recent developments in health care information technology and monitoring devices has made possible the creation of remote patient surveillance systems that increase the timeliness and quality of patient care. More convenient, less invasive monitoring devices, including patches, wearables, and biosensors, now allow for continuous physiological data to be gleaned from patients in a variety of care settings across the perioperative experience. These data can be bound into a single data repository, creating so-called data lakes. The high volume and diversity of data in these repositories must be processed into standard formats that can be queried in real time. These data can then be used by sophisticated prediction algorithms currently under development, enabling the early recognition of patterns of clinical deterioration otherwise undetectable to humans. Improved predictions can reduce alarm fatigue. In addition, data are now automatically queriable on a real-time basis such that they can be fed back to clinicians in a time frame that allows for meaningful intervention. These advancements are key components of successful remote surveillance systems. Anesthesiologists have the opportunity to be at the forefront of remote surveillance in the care they provide in the operating room, postanesthesia care unit, and intensive care unit, while also expanding their scope to include high-risk preoperative and postoperative patients on the general care wards. These systems hold the promise of enabling anesthesiologists to detect and intervene upon changes in the clinical status of the patient before adverse events have occurred. Importantly, however, significant barriers still exist to the effective deployment of these technologies and their study in impacting patient outcomes. Studies demonstrating the impact of remote surveillance on patient outcomes are limited. Critical to the impact of the technology are strategies of implementation, including who should receive and respond to alerts and how they should respond. Moreover, the lack of cost-effectiveness data and the uncertainty of whether clinical activities surrounding these technologies will be financially reimbursed remain significant challenges to future scale and sustainability. This narrative review will discuss the evolving technical components of remote surveillance systems, the clinical use cases relevant to the anesthesiologist's practice, the existing evidence for their impact on patients, the barriers that exist to their effective implementation and study, and important considerations regarding sustainability and cost-effectiveness.

Analysis of adverse outcomes in the post-anesthesia care unit based on anesthesia liability data

STUDY OBJECTIVE

The aim of this study is to provide a contemporary medicolegal analysis of claims brought against anesthesiologists in the United States for events occurring in the post-anesthesia care unit (PACU).

DESIGN

In this retrospective analysis, we analyzed closed claims data from the Controlled Risk Insurance Company (CRICO) Comparative Benchmarking System (CBS) database.

SETTING

Claims closed between January 1, 2010 and December 31, 2014 were included for analysis if the alleged damaging event occurred in a PACU and anesthesiology was named as the primary responsible service.

PATIENTS

Forty-three claims were included for analysis. Data regarding ASA physical status and comorbidities were obtained, whenever available. Ages ranged from 18 to 94. Patients underwent a variety of surgical procedures. Severity of adverse outcomes ranged from temporary minor impairment to death.

INTERVENTIONS

Patients receiving care in the PACU.

MEASUREMENTS

Information gathered for this study includes patient demographic data, alleged injury type and severity, operating surgical specialty, contributing factors to the alleged damaging event, and case outcome. Some of these data were drawn directly from coded variables in the CRICO CBS database, and some were gathered by the authors from narrative case summaries.

RESULTS

Settlement payments were made in 48.8% of claims. A greater proportion of claims involving death resulted in payment compared to cases involving other types of injury (69% vs 37%, p = 0.04). Respiratory injuries (32.6% of cases), nerve injuries (16.3%), and airway injuries (11.6%) were common. Missed or delayed diagnoses in the PACU were cited as contributing factors in 56.3% of cases resulting in the death of a patient. Of all claims in this series, 48.8% involved orthopedic surgery.

CONCLUSIONS

The immediate post-operative period entails significant risk for serious complications, particularly respiratory injury and complications of airway management. Appropriate monitoring of patients by responsible providers in the PACU is crucial to timely diagnosis of potentially severe complications, as missed and delayed diagnoses were a factor in a number of the cases reviewed.

Retrospective review of critical incidents in the post-anaesthesia care unit at a major tertiary hospital

INTRODUCTION

We reviewed patients with critical incidents that occurred in the post-anaesthesia care unit (PACU) at a major tertiary hospital, and assessed the effect of these incidents on PACU length of stay and discharge disposition.

METHODS

A retrospective review was conducted of patients in the PACU over a two-year period from 24 June 2011 to 23 August 2013. Data on critical incidents was recorded in the administrative database using a standardised data form.

RESULTS

There were 701 incidents involving 364 patients; 203 (55.8%) patients had American Society of Anesthesiologists (ASA) physical status I or II. The most common critical incidents were cardiovascular-related (n = 293, 41.8%), respiratory (n = 155, 22.1%), neurological (n = 52, 7.4%), surgical (n = 47, 6.7%) and airway-related (n = 34, 4.9%). There were two incidents of cardiac arrest and 25 incidents of unexpected reintubations. Many patients (n = 186, 51.2%) stayed for over four hours in the PACU due to critical incidents and 184 (50.5%) patients required a higher level of care postoperatively than initially planned. Some patients (n = 34, 9.3%) returned to the operation theatre for further management. A proportion of patients (n = 64, 17.6%) had unplanned intensive care unit admissions due to adverse events in the PACU.

CONCLUSION

A wide spectrum of critical incidents occur in the PACU, many of which are related to the cardiovascular and respiratory systems. Critical incidents have a major impact on healthcare utilisation and result in prolonged PACU stays and higher levels of postoperative care than initially anticipated.

Delayed recovery from anesthesia: A postgraduate educational review

Delayed awakening from anesthesia remains one of the biggest challenges that involve an anesthesiologist. With the general use of fast-acting anesthetic agents, patients usually awaken quickly in the postoperative period. The time to emerge from anesthesia is affected by patient factors, anesthetic factors, duration of surgery, and painful stimulation. The principal factors responsible for delayed awakening following anesthesia are anesthetic agents and medications used in the perioperative period. Nonpharmacological causes may have a serious sequel, hence recognizing these organic conditions is important. Certain underlying metabolic disorders such as hypoglycemia, severe hyperglycemia, and electrolyte imbalance, especially hypernatremia, hypoxia, hypercapnia, central anticholinergic syndrome, chronic hypertension, liver disease, hypoalbuminemia, uremia, and severe hypothyroidism may also be responsible for delayed recovery following anesthesia. Unexpected delayed emergence after general anesthesia may also be due to intraoperative cerebral hypoxia, hemorrhage, embolism, or thrombosis. Accurate diagnosis of the underlying cause is the key for the institution of appropriate therapy, but primary management is to maintain airway, breathing, and circulation. This comprehensive review discusses the risk factors, causes, evaluation and management of delayed recovery based on our clinical experience, and literature search on the internet, supported by the standard textbooks of anesthesiology.

Causes of tracheal re-intubation after craniotomy: A prospective study

Background:

Re-intubation of neurosurgical patients after a successful tracheal extubation in the operating room is not uncommon. However, no prospective study has ever addressed this concern. This study was aimed at analyzing various risk factors of re-intubation and its effect on patient outcome.

Methods:

Patients aged between 18-60 yrs and of ASA physical status I and II undergoing elective craniotomies over a period of two yrs were included. A standard anesthetic technique using propofol, fentanyl, rocuronium, and isoflurane/sevoflurane was followed, in all these patients. ‘Re-intubation’ was defined as the necessity of tracheal intubation within 72 hrs of a planned extubation. Data were collected and analyzed employing standard statistical methods.

Results:

One thousand eight hundred and fifty patients underwent elective craniotomy, of which 920 were included in this study. A total of 45 (4.9%) patients required re-intubation. Mean anesthesia duration and time of re-intubation were 6.3±1.8 and 24.6±21.9 hrs, respectively. The causes of re-intubation were neurological deterioration (55.6%), respiratory distress (22.2%), unmanageable respiratory secretion (13.3%), and seizures (8.9%). The most common post-operative radiological (CT scan) finding was residual tumor and edema (68.9%). Seventy-three percent of the re-intubated patients had satisfactory post-operative cough-reflex. The ICU and hospital stay, and Glasgow outcome scale at discharge were not significantly affected by different causes of re-intubation.

Conclusion:

Neurological deterioration is the most common cause of re-intubation following elective craniotomies owing to residual tumor and surrounding edema. A satisfactory cough reflex may not prevent subsequent re-intubation in post-craniotomy patients.

Nonawakening following general anaesthesia after ventriculo-peritoneal shunt surgery: An acute presentation of intracerebral haemorrhage

Emergence from general anaesthesia has been a process characterized by large individual variability. Delayed emergence from anaesthesia remains a major cause of concern both for anaesthesiologist and surgeon. The principal factor for delayed awakening from anaesthesia is assumed to be the medications and anaesthetic agents used in the perioperative period. However, sometimes certain non-anaesthetic events may lead to delayed awakening or even non-awakening from general anaesthesia. We report the non-anaesthetic cause (acute intracerebral haemorrhage) for non-awakening following ventriculo-peritoneal shunt surgery.

Successful extubation in the operating room after infratentorial craniotomy: the Cleveland Clinic experience

BACKGROUND

There is lack of information in the literature about the rate of successful extubation after infratentorial craniotomy and the risk factors associated with failed extubation. This retrospective analysis assessed the rate of successful extubation after infratentorial craniotomy in a tertiary hospital.

METHODS

Only infratentorial craniotomies for tumors, vascular malformations in the brainstem or cerebellum, and fourth ventricle cysts performed in prone position were included. Failed extubation was defined as the need for airway reintubation in the operating room (OR), postanesthesia care unit, or intensive care unit after surgery. Only those patients, in whom the primary reason for reintubation was respiratory failure, deteriorating level of consciousness, or inability to protect the airway were included in the statistical analysis. Prolonged intubation was defined as airway intubation longer than 48 hours from the initial intubation.

RESULTS

This is a retrospective study that included perioperative information from 145 adult patients. One hundred and twenty patients (82%) were primarily extubated in the OR and the rest remained intubated (18%). From the latter group, 9 (36%) and 16 (64%) were extubated in the postanesthesia care unit or intensive care unit, respectively. The rate of failed extubation within 24 hours after primary extubation in the OR was 0.83%. Patients not extubated in the OR had a statistically significant higher American Society of Anesthesiologists score, a longer length of surgery, a larger blood loss, and a longer stay in the hospital compared with those who were extubated in the OR.

CONCLUSIONS

We conclude that primary extubation in the OR after infratentorial craniotomy is feasible. However, cautions should be taken in patients with poor physical status undergoing vascular surgery and long procedures with potential significant fluid shifts.

Total intravenous anaesthesia with propofol and remifentanil for elective neurosurgical procedures

BACKGROUND AND OBJECTIVES

This was a prospective audit to assess the incidence and characteristics of early postoperative complications in the recovery room in extubated patients after elective neurosurgical procedures using propofol and remifentanil-based total intravenous anaesthesia.

METHODS

Vital signs (temperature, conscious level, respiratory rate, oxygen saturation, pulse and blood pressure) and postoperative complications (shivering, nausea, vomiting and cardiorespiratory) were analysed in 145 adult patients over a 1-yr period.

RESULTS

The overall shivering, postoperative nausea and vomiting and postoperative hypertension (systolic blood pressure more than 25% of the preoperative value) incidences were 30.3%, 16.6% and 35.2%, respectively. Fifty-one percent of the patients had at least one of the above complications. The complication rates were found to be widely different among various types of neurosurgery. The surgical procedures were divided into five groups: supratentorial craniotomy, posterior fossa craniotomy, intracranial vascular procedures, transphenoidal hypophysectomy and extracranial procedures. Median extubation time was similar in all groups and patients were fully conscious with no hypoxia in the recovery room. The intracranial vascular group had the highest shivering and postoperative nausea and vomiting rates (58.8% and 29.4%, respectively). In the supratentorial craniotomy group, 46% of the patients had hypertension. The overall complication rate (presence of any complications) was highest in the supratentfial craniotomy (55.4%), posterior fossa craniotomy (75%) and intracranial vascular (76.5%) groups. Shivering and overall complication rate was significantly related to the anaesthetic time (P<or=0.001 and 0.02, respectively).

CONCLUSIONS

Despite the potential advantages of total intravenous anaesthesia in titratability, rapid return of consciousness and reduced respiratory complications, making it suitable for planned extubation at the end of neurosurgery, the postoperative complications of shivering, postoperative nausea and vomiting and hypertension were still high.

A Description of Intraoperative and Postanesthesia Complication Rates

This article reviews the current rate of intraoperative and postanesthesia complications in an acute care hospital and Level II Trauma center. One thousand patients were assessed for intraoperative and postoperative complications and compared with a previous study from 1991 in a different institution. The overall rate of complications in this current study indicated an overall complication rate (combined intraoperative and PACU) of 26% with an intraoperative rate of 3.8% and a PACU rate of 23.4%. Although a slight improvement from a study in 1991, there continue to be many similarities.

An analysis of reintubations from a quality assurance database of 152,000 cases

STUDY OBJECTIVE

To determine if the majority of reintubations, a potentially preventable adverse event, were predominantly due to residual muscle relaxant effects, we analyzed our quality assurance database to identify the causes of reintubation.

DESIGN

Retrospective study.

SETTING

University of Michigan Department of Anesthesiology Quality Assurance (QA) database.

MEASUREMENTS

We analyzed QA records from 152,939 anesthetic cases performed from 1994 to 1999 at our institution. Of these cases, 107,317 were performed with a general anesthetic. The medical record of each patient requiring reintubation was obtained and reviewed to determine the cause of the reintubation.

RESULTS

A total of 191 reintubation events were identified. One hundred twelve of the 191 (59%) reintubations were due to respiratory problems; 11 of the 191 (6%) reintubations were due to complications of neuromuscular blocking drug use. Other causes were unintentional extubation, surgical complication, endotracheal tube problems, and cardiac problems. One hundred five reintubations (105/191, 55%) occurred in the operating room and 86 (86/191, 45%) occurred in the postanesthesia care unit.

CONCLUSION

Respiratory complications were the most common cause of reintubation in the perioperative period. Complications related to the neuromuscular blocking drugs were the fourth most common cause of reintubation. More reintubations occurred in the operating room than the postanesthesia care unit. Muscle relaxant effect and opioid effect are rare causes of respiratory failure in the anesthetized patient in the immediate postoperative period.

Consent and anaesthetic risk

The incidences of mortality and morbidity associated with anaesthesia were reviewed. Most of the published incidences for common complications of anaesthesia vary considerably. Where possible, a realistic estimate of the incidence of each morbidity has been made, based on the best available data. Perception of risk and communication of anaesthetic risk to patients are discussed. The incidences of anaesthetic complications are compared with the relative risks of everyday events, using a community cluster logarithmic scale, in order to place the risks in perspective when compared with other complications and with the inherent risks of surgery. Documentation of these risks and discussion with patients should allow them to be better informed of the relative risks of anaesthetic complications. Depending on specific comorbidities and the severity of operation, these risks associated with anaesthesia may increase for any one individual.

Recovery room incidents: a review of 419 reports from the Anaesthetic Incident Monitoring Study (AIMS)

Four hundred and nineteen incidents that occurred in the recovery room were extracted from the Anaesthetic Incident Monitoring Study database, representing 5% of the total database of 8372 reports. Incidents were reported mainly in daylight hours, with over 50% occurring in ASA 1-2 patients. The most common presenting problems related to respiratory/airway issues (183; 43%), cardiovascular problems (99; 24%) and drug errors (44; 11%). One hundred and twenty-two events (29%) led to a major physiological disturbance and required management in the High Dependency Unit or Intensive Care Unit. Contributing factors cited included error of judgement (77; 18%), communication failure (57; 14%) and inadequate pre-operative preparation (29; 7%), whilst factors minimising the incident included previous experience (97; 23%), detection by monitoring (72; 17%) and skilled assistance (54; 13%). Staffing and infrastructure of the recovery room needs to be supported, with ongoing education and quality assurance programmes developed to ensure that such events can be reduced in the future.

Menstrual cycle irregularity and the incidence of nausea and vomiting after laparoscopy

Gender is an important risk factor for postoperative nausea and vomiting. Menstrual cycle phase has also been implicated as a further variable in female patients. It is not clear whether a history of an irregular menstrual cycle is a significant variable and studies to date have not examined this. The influence of an irregular menstrual cycle on nausea and vomiting after laparoscopy was evaluated in a blinded, prospective, observational study. One hundred and fifty-nine patients scheduled for laparoscopy and dye investigation were included. Anaesthetic technique and postoperative analgesia were standardised. In comparison with patients who had a regular cycle, an irregular menstrual cycle increased the incidence of nausea or vomiting from 20.5% to 40.5% (absolute difference 20%; 95% CI 0.03-0.37, p = 0.01). Other variables were similar between the groups. An irregular menstrual cycle appears to increase the risk of postoperative nausea and vomiting.

Cerebral embolization presenting as delayed, severe obtundation in the postanesthesia care unit after total hip arthroplasty

Catastrophic neurologic events occur rarely postoperatively and must be diagnosed quickly. A 63-year-old woman who had undergone uneventful total hip arthroplasty experienced obtundation after admission to the postanesthesia care unit. Cranial magnetic resonance imaging revealed multiple lesions consistent with ischemia or infarction, and fat cerebral embolism was diagnosed. We describe the numerous complications that may occur in patients in the postanesthesia care unit and review the differential diagnosis of altered mental status in such patients. Paradoxical cerebral fat embolization must be considered in the differential diagnosis of altered mental status after pelvic or long bone fracture or lower extremity major joint replacement, and this condition may occur despite normal pulmonary function and no patent foramen ovale or right-to-left intracardiac shunt. Magnetic resonance imaging with T2-weighted sequences is the cranial imaging study of choice for early evaluation of patients with sudden multifocal neurologic deficits and suspected fat embolism syndrome.

Clinical impact of hypnotic-titration guidelines based on EEG bispectral index (BIS) monitoring during routine anesthetic care

STUDY OBJECTIVES

To examine the impact on perioperative care of routine Bispectral Index (BIS) monitoring during general anesthesia throughout an entire operating room (OR) suite.

DESIGN

Open, observational trial with retrospective analysis of guideline performance. Data were analyzed from 1,552 adult patients receiving general anesthesia with surgical times of at least 1 hour and who were extubated by postanesthesia care unit (PACU) discharge. Staff were trained using a simple decision matrix, which integrated BIS titration goals with anesthetic management. Unmonitored patients were compared to either BIS-monitored patients or to performance subgroups based on BIS measurements recorded during anesthetic maintenance ("deep", BIS < 50; "target", 50-65; "light", >65).

SETTING

Large, urban academic/trauma center.

MEASUREMENTS AND MAIN RESULTS

Demographic profiles of all groups and subgroups were similar. Anesthetic emergence, recovery times, and volatile drug use were significantly shortened or reduced only when BIS values were maintained between 50 and 65. Extubation time from end of surgery decreased by 2.1 minutes from 5.7+/-7 (37%); OR exit time decreased by 2.2 minutes from 9.3+/-6 (24%); eligibility for phase 1 PACU discharge decreased by 4 minutes from 22+/-42 (23%); and actual PACU discharge decreased by 15 minutes from 130+/-78 (7%). PACU extubation frequency decreased from 6.9% to 2.6%. Modest decreases in total intraoperative drug use were noted with an increase in PACU analgesic administration.

CONCLUSIONS

Routine application of BIS monitoring throughout an OR suite impacted clinical outcome only if guideline targets were met. BIS values within the last 30 minutes of surgery were not predictive of emergence or recovery. Hypnotic maintenance at BIS < 50 did not confer any clinical advantage over unmonitored cases. Anesthetic maintenance at BIS values between 50 and 65 was associated with shortened emergence and recovery from general anesthesia.

Adverse sedation events in pediatrics: a critical incident analysis of contributing factors

OBJECTIVE

Factors that contribute to adverse sedation events in children undergoing procedures were examined using the technique of critical incident analysis.

METHODOLOGY

We developed a database that consists of descriptions of adverse sedation events derived from the Food and Drug Administration's adverse drug event reporting system, from the US Pharmacopeia, and from a survey of pediatric specialists. One hundred eighteen reports were reviewed for factors that may have contributed to the adverse sedation event. The outcome, ranging in severity from death to no harm, was noted. Individual reports were first examined separately by 4 physicians trained in pediatric anesthesiology, pediatric critical care medicine, or pediatric emergency medicine. Only reports for which all 4 reviewers agreed on the contributing factors and outcome were included in the final analysis.

RESULTS

Of the 95 incidents with consensus agreement on the contributing factors, 51 resulted in death, 9 in permanent neurologic injury, 21 in prolonged hospitalization without injury, and in 14 there was no harm. Patients receiving sedation in nonhospital-based settings compared with hospital-based settings were older and healthier. The venue of sedation was not associated with the incidence of presenting respiratory events (eg, desaturation, apnea, laryngospasm, approximately 80% in each venue) but more cardiac arrests occurred as the second (53.6% vs 14%) and third events (25% vs 7%) in nonhospital-based facilities. Inadequate resuscitation was rated as being a determinant of adverse outcome more frequently in nonhospital-based events (57.1% vs 2.3%). Death and permanent neurologic injury occurred more frequently in nonhospital-based facilities (92.8% vs 37.2%). Successful outcome (prolonged hospitalization without injury or no harm) was associated with the use of pulse oximetry compared with a lack of any documented monitoring that was associated with unsuccessful outcome (death or permanent neurologic injury). In addition, pulse oximetry monitoring of patients sedated in hospitals was uniformly associated with successful outcomes whereas in the nonhospital-based venue, 4 out of 5 suffered adverse outcomes. Adverse outcomes despite the benefit of an early warning regarding oxygenation likely reflect lack of skill in assessment and in the use of appropriate interventions, ie, a failure to rescue the patient.

CONCLUSIONS

This study-a critical incident analysis-identifies several features associated with adverse sedation events and poor outcome. There were differences in outcomes for venue: adverse outcomes (permanent neurologic injury or death) occurred more frequently in a nonhospital-based facility, whereas successful outcomes (prolonged hospitalization or no harm) occurred more frequently in a hospital-based setting. Inadequate resuscitation was more often associated with a nonhospital-based setting. Inadequate and inconsistent physiologic monitoring (particularly failure to use or respond appropriately to pulse oximetry) was another major factor contributing to poor outcome in all venues. Other issues rated by the reviewers were: inadequate presedation medical evaluation, lack of an independent observer, medication errors, and inadequate recovery procedures. Uniform, specialty-independent guidelines for monitoring children during and after sedation are essential. Age and size-appropriate equipment and medications for resuscitation should be immediately available regardless of the location where the child is sedated. All health care providers who sedate children, regardless of practice venue, should have advanced airway assessment and management training and be skilled in the resuscitation of infants and children so that they can successfully rescue their patient should an adverse sedation event occur.

An audit of airway problems in the recovery room

It has recently been suggested that recovery rooms should have dedicated anaesthetic cover during working hours to deal with serious life-threatening problems. This audit was undertaken to determine the incidence and severity of airway problems that occurred in the recovery room at a District General Hospital. One thousand consecutive patients who received a general anaesthetic were assessed. If an airway problem was identified, the patient's notes were examined to document the type of surgery and any predisposing factors which may have contributed. The incidence of airway problems in this study was found to be 2.8%, which was in agreement with previous studies and appears too low to warrant a full-time anaesthetic presence.

Early postoperative complications following neurosurgical procedures

PURPOSE

To assess the incidence and characteristics of early postoperative complications in patients following neurosurgical procedures.

METHODS

All patients undergoing neurosurgery during a four month period were followed postoperatively for up to four hours in the post anesthetic care unit or intensive care unit. Patient information and all complications were documented by the investigators on a standardized form. Complications were classified as respiratory, cardiovascular, nausea and vomiting, shivering and other. Risk factors analyzed for the occurrence of complications included age, sex, ASA status, type of surgery, elective or emergency surgery and postoperative placement.

RESULTS

Four hundred eighty six adult patients were followed, but in 55 patients the trachea remained intubated during the four hour study period and they were eliminated from the analysis of postoperative complications. At least one complication occurred in 54.5% of the remaining 431 patients. Respiratory problems occurred in 2.8%, trauma to the airway in 4.4%, cardiovascular complications in 6.7%, neurological in 5.7% and nausea and/or vomiting in 38%. The highest incidence of patients with complications was during spine (65%) and vascular (66%) surgery, compared with tumour (47%) and other (43%) surgery, P < 0.05. Other risk factors included age < 70 yr for nausea and vomiting (P < 0.02), and elective surgery for spine and vascular surgery (P < 0.001).

CONCLUSION

There was a high incidence of early postoperative complications in neurosurgical patients. The most common problem was nausea and vomiting especially in the younger patient undergoing elective spine surgery.

Measuring anaesthetic outcomes

We have identified some of the most frequently measured anaesthetic outcomes and their independent risk factors, and discussed the limitations and advantages in using various risk adjustment strategies. Many studies suggest that preoperative assessments may contribute to preventing the occurrence of anaesthetic-related morbidity and mortality, and to high levels of patient satisfaction. The use of health status measurements as a preoperative screening tool in assessing anaesthetic risk offers a potential area for future work. Research into measuring anaesthetic outcomes in a reliable and valid manner will be an important tool in improving standards of anaesthetic practice and in delivering quality anaesthesia to our patients.

Death associated with anaesthesia and surgery in Finland in 1986 compared to 1975

Mortality associated with anaesthesia and surgery in Finland in 1986 was studied using a retrospective method and was compared with the results of a similar study performed in 1975. The total number of procedures was 325,585. 570 patients fulfilled one of the three criteria: 1. The patient died within three days of a procedure needing anaesthesia. 2. The patient died more than three days after a procedure needing anesthesia, but had suffered a cardiac arrest or been resuscitated, or there was a surgical or an anaesthesiological complication contributing to the death. 3. The patient suffered a major handicapping neurological (or other) deficit, which was associated with anaesthesia, or there was a surgical or an anaesthesiological complication possibly contributing to the death or handicap (no patients). The number of consultant anaesthesiologists had more than doubled since 1975. At the same time there was also a significant increase in recovery room and intensive care facilities. Surgery was the main contributing factor in the death of 22 (frequency 0.68/10,000 procedures), and anaesthesia in the death of five (frequency 0.15/10,000 procedures) patients. The role of surgery had decreased to about one third and the role of anaesthesia to less than one tenth as the main cause of death associated with anaesthesia and surgery compared to the year 1975. 95.3% of all the patients died mainly because of co-existing medical or surgical disease.

The Australian Incident Monitoring Study. Recovery room incidents in the first 2000 incident reports

Of the first 2000 incidents reported to the Australian Incident Monitoring Study 120 (6%) occurred in the recovery room after general, regional or local anaesthesia. Over two thirds (69%) of these involved the respiratory system, 19% were cardiovascular, 3% involved the central nervous system and 9% were miscellaneous in nature. These recovery room incidents were associated with significantly more adverse outcomes (56%) than incidents in the operating theatre (24%). The types and relative frequencies of these recovery room incidents were similar to those of serious recovery complications in a recent analysis of closed malpractice claims; this suggests that incident monitoring may be useful in the study and prevention of recovery room complications. Over three quarters (77%) of all recovery incidents (and 88% of respiratory incidents) were detected clinically; the remainder were first detected by a monitor. A theoretical analysis showed that over 95% of respiratory events, had they been allowed to evolve, would have been detected by pulse oximetry before organ damage occurred, emphasising the potential importance of pulse oximetry in reducing adverse outcome from any complication in the recovery ward which might be "missed" by clinical observation. The findings of this study underline the importance of having an adequate number of trained recovery nursing staff supported by the availability of a pulse oximeter for each patient at least until the return of protective reflexes and the ability to maintain adequate arterial saturation has been established.

Quality assessment in personal anaesthetic practice

Continuing education can improve anaesthetic practice if it is relevant to an individual's work and complications. A practice profile delineates the significance of untoward events. A personal audit of consecutive anaesthetics and associated complications is presented as a first step to checking one's competence over the course of years.

Level of consciousness on arrival in the recovery room and the development of early respiratory morbidity

An audit review of 16,065 patients undergoing operative procedures under general anaesthesia was carried out to examine the relationship between early postoperative respiratory complications and the level of consciousness of patients on arrival in the recovery room. In patients aged over ten years, the incidence of respiratory complications was significantly (P less than 0.005) related to the level of consciousness independent of ASA grade or age. Since the level of consciousness of patients arriving in the recovery room could be modified by changes to anaesthetic practice it is concluded that a significant reduction in respiratory complications might be possible if anaesthetists used general anaesthetic techniques which returned patients awake to the recovery room.

A prospective survey of anaesthetic critical events in a teaching hospital

A survey of anaesthetic critical events based on voluntary anonymous reports was undertaken over a two and a half year period within a teaching hospital Department of Anaesthesia. At the end of the survey 167 reports were analysed. Human error was a contributing factor in 82% of events. Inadequate preoperative patient assessment or preparation, problems in the area of human/equipment interface and various stress factors for the anaesthetist featured significantly in the survey. The method enables the collection of objective data on factors contributing to anaesthetic and surgical risk and the formulation and evaluation of potential corrective strategies. It also facilitates harmonious peer review via individual and group feedback activities. The adoption of such a survey on a wider scale is seen as a valuable part of quality assurance in the continuing attempt to increase patient safety.