Epidemiology in anaesthesia. III: Mortality risk in patients with coexisting physical disease

Risk factors affecting all-cause mortality in cats hospitalized by a referral soft tissue service

OBJECTIVES

The objective of this study was to describe the all-cause mortality rate in cats hospitalized by the soft tissue surgery service of an academic referral hospital over a 5-year period and to identify specific risk factors for mortality. The hypotheses were that the all-cause mortality rate during hospitalization would be low, and cats undergoing emergency surgery and those with an American Society of Anesthesiologists (ASA) status of 3 or more would be at increased risk for mortality.

METHODS

The case log of cats hospitalized by the soft tissue surgery service at the University of Georgia was searched retrospectively to identify all cats hospitalized in the years 2015-2020. Data collected about each cat included age, sex and neuter status, weight, body condition score (1-9), pre-existing heart disease, chronic kidney disease, concurrent infection or cancer, emergency status, time of surgery (daytime vs after hours, which was defined as after 4 pm), if the surgery was performed on a weekday or weekend, and general type of surgery. Univariable logistic regressions were implemented to test and estimate odds ratios for the effects of risk factors on in-hospital mortality. A multivariable logistic regression was developed that initially included all risk factors with P <0.05 on univariable analysis. Log-likelihood ratio test P values and profile-likelihood confidence intervals were reported.

RESULTS

The all-cause mortality rate was 6.1%. Analysis was limited because of low mortality, but multivariable analysis identified increasing ASA status and emergency surgery as significant risk factors for increased mortality while hospitalized.

CONCLUSIONS AND RELEVANCE

The findings of this study confirmed that increasing ASA status and emergency procedures are significant risk factors for mortality in cats. Clinicians should be aware of these risk factors and consider how to best monitor and manage these feline patients.

An Exploration of the Value of Elective Health Checks in UK Zoo-Housed Gibbons

Elective health checks form an important part of the preventative healthcare of many zoo-housed animals. These procedures are not without risk or financial expenditure, meaning careful cost-benefit analysis is required when determining the frequency and intensity with which they are implemented. This study evaluated the value of elective health checks (n = 74) carried out on 33 gibbons at a single UK zoological collection from 2011 to 2018. Data were categorised by health check type, animal age, clinical findings and outcome. Univariable binary logistic regression and multivariable modelling were used to identify factors associated with the likelihood of actionable (clinically significant) outcomes. In total, 51.35% of all elective health checks resulted in an actionable outcome. Elderly heath checks had 13.64 times greater odds of an actionable outcome and 34 times greater odds of a significant radiographic finding, when compared to routine (non-elderly) health checks. Our findings suggest that 75% wild longevity is a suitable threshold for identifying elderly captive gibbons and increasing health check frequency. Whilst further work is needed to ascertain whether these findings can be extrapolated to other collections and/or species, this study demonstrates how the analysis of clinical data can aid in the implementation of an effective and evidence-based preventative healthcare plan.

[Perioperative risk and mortality after major surgery]

Although anesthesia-associated mortality has been significantly reduced down to 0.00068-0.00082% over the last decades, recent studies have revealed a high perioperative mortality of 0.8- 4%. Apart from anesthesia and surgery-induced major complications, perioperative mortality is primarily negatively influenced by individual patient comorbidities. These risk factors predispose for acute critical incidents (e.g., myocardial infarction); however, the majority of fatal complications are a result of slowly progressing conditions, particularly infections or the sequelae of systemic inflammation. This implicates a broad window of opportunity for the detection and treatment of slow-onset complications to improve the perioperative outcome. The term "failure to rescue" (FTR), i.e., the proportion of patients who die from major complications compared to the number of all patients with complications, has been introduced as a valid indicator for the quality of perioperative care. Growing evidence has already shown that FTR is an underestimated factor in perioperative medicine accounting for or at least being involved in the development of postoperative mortality. While the incidence of severe postoperative complications amazingly does not show much variation between hospitals, FTR shows significant differences implying a major potential for improvement. With 14 million surgical procedures per year in Germany, a postoperative mortality of approximately 1% and an avoidable FTR rate of 40% mean that there are an estimated 60,000 preventable deaths per year. Hence, in the future it will be imperative to (1) identify patients at risk, (2) to prevent the development of postoperative complications with the use of adequate adjunctive therapeutic strategies, (3) to establish surveillance and monitoring systems for the early detection of postoperative complications and (4) to treat postoperative complications efficiently and in time when they arise.

Depth of Anesthesia as a Risk Factor for Perioperative Morbidity

Introduction. The prognostic value of age, physical status, and duration of surgery on perioperative course has been extensively studied. However, the impact of deep hypnotic time (time when Bispectral Index values are less than 40) has not been well evaluated. Methods. We designed an observational study to clarify the relative influence of deep hypnotic time (DHT) on outcome. Eligible participants were mentally stable patients over 18 years old scheduled for elective major abdominal surgery. In total, 248 patients enrolled. Data were analyzed using Fisher's exact test and multiple logistic regression. Results. Five variables (DHT, hypotension, age, comorbidity, and duration of surgery) showed statistically significant association with complications, when examined independently. However, when all variables were examined together in a multiple logistic regression model, age and comorbidity were no longer associated with outcome. DHT, hypotension, and duration of surgery were significant predictors of "complications," and "hypotension" was a significant predictor of prolonged hospital stay (P < 0.001).  Conclusion. Deep hypnotic time emerged as a new factor associated with outcome, and its impact compared to other factors such as age, surgery duration, hypotension, and comorbidity is redefined. Monitoring and managing depth of anesthesia during surgery are important and should be part of careful operation planning.

Restrictive strategy of intraoperative fluid maintenance during optimization of oxygen delivery decreases major complications after high-risk surgery

Introduction

Optimal fluid management is crucial for patients who undergo major and prolonged surgery. Persistent hypovolemia is associated with complications, but fluid overload is also harmful. We evaluated the effects of a restrictive versus conventional strategy of crystalloid administration during goal-directed therapy in high-risk surgical patients.

Methods

We conducted a prospective, randomized, controlled study of high-risk patients undergoing major surgery. For fluid maintenance during surgery, the restrictive group received 4 ml/kg/hour and the conventional group received 12 ml/kg/hour of Ringer's lactate solution. A minimally invasive technique (the LiDCO monitoring system) was used to continuously monitor stroke volume and oxygen delivery index (DO₂I) in both groups. Dobutamine was administered as necessary, and fluid challenges were used to test fluid responsiveness to achieve the best possible DO₂I during surgery and for 8 hours postoperatively.

Results

Eighty-eight patients were included. The patients' median age was 69 years. The conventional treatment group received a significantly greater amount of lactated Ringer's solution (mean ± standard deviation (SD): 4, 335 ± 1, 546 ml) than the restrictive group (mean ± SD: 2, 301 ± 1, 064 ml) (P < 0.001). Temporal patterns of DO₂I were similar between the two groups. The restrictive group had a 52% lower rate of major postoperative complications than the conventional group (20.0% vs 41.9%, relative risk = 0.48, 95% confidence interval = 0.24 to 0.94; P = 0.046).

Conclusions

A restrictive strategy of fluid maintenance during optimization of oxygen delivery reduces major complications in older patients with coexistent pathologies who undergo major surgery.

Trial registration

ISRCTN: ISRCTN94984995

Correlation of higher preoperative American Society of Anesthesiology grade and increased morbidity and mortality rates in patients undergoing spine surgery

OBJECT

Patients with varied medical comorbidities often present with spinal pathology for which operative intervention is potentially indicated, but few studies have examined risk stratification in determining morbidity and mortality rates associated with the operative treatment of spinal disorders. This study provides an analysis of morbidity and mortality data associated with 22,857 cases reported in the multicenter, multisurgeon Scoliosis Research Society Morbidity and Mortality database stratified by American Society of Anesthesiologists (ASA) physical status classification, a commonly used system to describe preoperative physical status and to predict operative morbidity.

METHODS

The Scoliosis Research Society Morbidity and Mortality database was queried for the year 2007, the year in which ASA data were collected. Inclusion criterion was a reported ASA grade. Cases were categorized by operation type and disease process. Details on the surgical approach and type of instrumentation were recorded. Major perioperative complications and deaths were evaluated. Two large subgroups--patients with adult degenerative lumbar disease and patients with major deformity--were also analyzed separately. Statistical analyses were performed with the chi-square test.

RESULTS

The population studied comprised 22,857 patients. Spinal disease included degenerative disease (9409 cases), scoliosis (6782 cases), spondylolisthesis (2144 cases), trauma (1314 cases), kyphosis (831 cases), and other (2377 cases). The overall complication rate was 8.4%. Complication rates for ASA Grades 1 through 5 were 5.4%, 9.0%, 14.4%, 20.3%, and 50.0%, respectively (p = 0.001). In patients undergoing surgery for degenerative lumbar diseases and major adult deformity, similarly increasing rates of morbidity were found in higher-grade patients. The mortality rate was also higher in higher-grade patients. The incidence of major complications, including wound infections, hematomas, respiratory problems, and thromboembolic events, was also greater in patients with higher ASA grades.

CONCLUSIONS

Patients with higher ASA grades undergoing spinal surgery had significantly higher rates of morbidity than those with lower ASA grades. Given the common application of the ASA system to surgical patients, this grade may prove helpful for surgical decision making and preoperative counseling with regard to risks of morbidity and mortality.

Geriatric care in the surgical intensive care unit

We describe the physiology of aging and its effect on elderly, critically ill, surgical patients. Postoperative age-specific complications and their management will be reviewed. The number of elderly persons, defined as those >65 yrs of age, is the fastest growing segment of the U.S. population. As a result, the frequency of surgery, both elective and emergent, performed on elderly patients will increase. Aging is associated with a decrease in the physiologic reserve; thus, many elderly persons are unable to compensate for the increased metabolic demands that accompany acute illness or injury. This inability to compensate leads to increased rates of postoperative complications and death. Aggressive, goal-directed management in the surgical intensive care unit is beneficial for the geriatric patient. The management of the elderly, surgical, critical care patient is extremely challenging. Understanding age-related physiologic changes will help guide treatment to maximize outcome and prevent complications.

[Peri-operative adjustment and treatment of diabetes mellitus]

In all disciplines of operative medicine the number of patients who suffer from diabetes mellitus is increasing dramatically. The reason is that nowadays up to 10% of the population is suffering from this disease. These patients must be treated with respect to the diabetes and also subsequent related conditions to prevent peri-operative complications. A special problem is that many patients do not know that they are suffering from diabetes. Pre-operatively and during the peri-operative course the coordinated efforts of surgeons, anaesthesiologists and diabetes specialists are essential to reach an optimal result. In all hospitals obligatory algorithms must be established for the treatment of these patients.

Mortality in diabetic patients undergoing non-cardiac surgery: a 7-year follow-up study

BACKGROUND

The prognosis of diabetic patients after non-cardiac surgery remains controversial. This study was designed to compare the long-term mortality between diabetic and non-diabetic control patients undergoing non-cardiac surgery and to evaluate the possible risk factors.

METHODS

We investigated 274 consecutive diabetic patients and 282 non-diabetic control patients who underwent non-cardiac surgery within 1 year in a tertiary care hospital in Finland. The control group was matched for the same type of operations. Patients were followed for up to 7 years on average. The main outcome measure was mortality within 7 years.

RESULTS

Mortality both in the short-term postoperatively (< or =21 days) and in the long-term (up to 87 (1/2) months) was significantly higher in the diabetic patients compared with the non-diabetic group: 3.5 vs. 0% (P<0.05) and 37.2 vs. 15% (P<0.00001), respectively. The major causes of death among diabetic subjects were diseases of the cardiovascular system (56.8%) compared with non-diabetic patients (18.6%), P<0.0001. We found that diabetes mellitus per se is not a risk factor for post-operative mortality but a combination of variables had a significant effect on both short- and long-term mortality.

CONCLUSION

Diabetic patients undergoing non-cardiac surgery had a significantly higher incidence of short-term post-operative and long-term mortality compared with non-diabetic subjects. We propose a model of predictors of death among diabetic individuals undergoing non-cardiac surgery within a 7-year follow-up. The majority of deaths were associated with cardiovascular diseases.

Perioperative complications in obese women vs normal-weight women who undergo vaginal surgery

OBJECTIVE

The purpose of this study was to compare the incidence of perioperative complications in obese and normal-weight patients who undergo vaginal urogynecologic surgery.

STUDY DESIGN

A retrospective cohort analysis was conducted for obese patients (body mass index, > or = 30 kg/m2) who underwent vaginal surgery and who were matched with patients with normal body mass indices (> 18.5 kg/m2 but < 30 kg/m2) by surgical procedures. Demographic information, comorbidities, and perioperative (< or = 6 weeks) complications were documented. Logistic regression analysis was used to compare the incidence of perioperative complications and to adjust for baseline differences.

RESULTS

Seven hundred forty-two patients underwent vaginal surgery during the study period; 235 women were considered to have obese body mass indices. We matched 194 of these patients with normal-weight control subjects. There was no statistical difference in the proportion of subjects who had at least 1 perioperative complication (20% [obese] vs 15% [nonobese]). However, obese subjects were more likely to have an operative site infection (adjusted odds ratio, 5.5; [95% CI, 1.7-24.7]; P = .01).

CONCLUSION

The overall perioperative complication rate in obese and nonobese women is low, with obesity as an independent risk factor for the development of operative site infections.

Corrected incidences of co-morbidities – a statistical approach for risk-assessment in anesthesia using an AIMS

OBJECTIVE

In anesthesia and intensive care logistic regression analysis are often used to generate predictive models for risk assessment. Strictly seen only independent variables should be represented in such prognostic models. Using anesthesia-information-management-systems a lot of (depending) information is stored in a database during the preoperative ward round. The objective of this study was to evaluate a statistical algorithm to process the different dependent variables without losing the information of each variable on patient's conditions.

METHOD

Based on data about prognostic models in anesthesia an iterative statistical algorithm was initiated to summarize dependent variables to subscores. Seven subscores out of several preoperative variables were calculated corresponding to the proper incidence and the correlation to the occurrence of intraoperative cardiovascular events was evaluated. After that first step logistic regression was used to build a predictive model out of the seven subscores, 10 patient-related, and two surgery-related variables. Performance of the prognostic model was assessed using analysis of discrimination and calibration.

RESULT

Four out of seven subscores together with age, type and urgency of surgery are represented in the prognostic model to predict the occurrence of intraoperative cardiovascular events. The prognostic model demonstrated good discriminative power with an area under the ROC curve (AUC) of 0.734.

CONCLUSION

Due to reduced calibration, the clinical use of the prediction model is limited.

Efficacy of National Nosocomial Infection Surveillance score, acute-phase proteins, and interleukin-6 for predicting postoperative infections following major gastrointestinal surgery

CONTEXT AND OBJECTIVE

Postoperative infections should be detected earlier. We investigated the efficacy of the National Nosocomial Infection Surveillance (NNIS) score, interleukin-6 (IL-6) and various acute-phase proteins for predicting postoperative infections.

DESIGN AND SETTING

Case series study at the Júlio Müller University Hospital.

METHODS

Thirty-two patients who underwent major gastrointestinal procedures between June 2004 and February 2005 were studied. The NNIS score and the evolution of serum IL-6 and various acute-phase proteins (C-reactive protein [CRP], albumin, prealbumin and transferrin) were correlated with postoperative infections and length of hospital stay (LOS).

RESULTS

NNIS > 1 (p = 0.01) and low preoperative albumin (p = 0.02) significantly correlated with infection. IL-6 and CRP increased significantly more in patients with infections. Multivariate analysis showed greater risk of infection when NNIS > 1 (odds ratio, OR = 10.66; 95% confidence interval, CI: 1.1-102.0; p = 0.04); preoperative albumin < 3 g/dl (OR = 8.77; 95% CI: 1.13-67.86; p = 0.03); CRP > 30 mg/l on the second postoperative day (OR = 8.27; 95% CI: 1.05-64.79; p = 0.03) and > 12 mg/l on the fifth postoperative day (OR = 25.92; 95% CI: 2.17-332.71; p < 0.01); and IL-6 > 25 pg/ml on the fifth postoperative day (OR = 15.46; 95% CI: 1.19-230.30; p = 0.03). Longer LOS was associated with cancer, transferrin, IL-6 and albumin (p < 0.05).

CONCLUSIONS

NNIS, albumin, CRP and IL-6 may be useful as predictive markers for postoperative infections. For predicting LOS, malignant condition, transferrin, albumin and IL-6 are useful.

Modeling Perioperative Risk: Can Numbers Speak Louder Than Words?

Perioperative care is one of the most complex segments of medicine, because it imposes unique and unprecedented stress on the patient and requires the participation of multiple medical specialists. For this reason, the concept of risk management is ideally suited for application in the perioperative period. The authors believe that risk stratification systems applied to perioperative management should address the three dimensions of patient condition, surgical risk and invasiveness, and anesthetic complexity. They have proposed a system that integrates these factors to document and communicate the relevant elements affecting the "shape" of preoperative patients. Admittedly far short of the ideal formula, we hope this nonetheless prompts efforts to establish more uniform means of assessment and communication and provides a foundation for this endeavor. The old adage can be modified: "if your patient rates more than two ASPIRIN, call me before the morning (of surgery)."

Malpractice and system of expertise in anaesthetic procedures in Turkey

Deaths which occur during the administration of anaesthetics require medicolegal investigations. The objective of this study is to form a database for future comparisons related to anaesthetic-associated malpractice claims and also to investigate the system of expertise, pertaining to such procedures. The decisions of the Supreme Health Council, whose expert opinion is requested by legal authorities (judges, prosecutors) for health workers brought to trial in a criminal court, were examined retrospectively over the period 1995-1999. In 21 (2.3%) of the 888 decision reports prepared by the council the team members (the anaesthesiologist , the anaesthetic assistant, the anaesthetic technician, the nurse) were directly interrogated. Data concerning these 21 council decisions were evaluated within the scope of this study. It was found that 57% of the 21 decisions were related to medical procedures carried out in state hospitals. Of the 21 cases, 62% were males, 38% females. General anaesthesia was applied to 19 of the cases while one received regional (local) anaesthesia and one axillary blockade. Twenty died of complications associated with anaesthesia. Autopsy was performed on 11 (55%) of the dead. Health workers were found to have different degrees of liability in the 16 (76%) of the 21 decision reports. In their medical practices, anaesthesiologists , like other specialists, are subject to legal procedures in the country where they perform their duties, to national and international principles of ethics, and to diagnostic and curative standards/procedures relevant to the scientific level of the country concerned. In anaesthetic malpractice claims, certain standards need to be followed in inquiries and approaches so as to determine the real reasons behind the disabilities and/or deaths which occur. In order that sound evaluations could be made in such cases, the experts as well as the system of expertise should be efficient and authorized.

The incidence and prediction of automatically detected intraoperative cardiovascular events in noncardiac surgery

The objective of this study was to evaluate prognostic models for quality assurance purposes in predicting automatically detected intraoperative cardiovascular events (CVE) in 58458 patients undergoing noncardiac surgery. To this end, we assessed the performance of two established models for risk assessment in anesthesia, the Revised Cardiac Risk Index (RCRI) and the ASA physical status classification. We then developed two new models. CVEs were detected from the database of an electronic anesthesia record-keeping system. Logistic regression was used to build a complex and a simple predictive model. Performance of the prognostic models was assessed using analysis of discrimination and calibration. In 5249 patients (17.8%) of the evaluation (n = 29437) and 5031 patients (17.3%) of the validation cohorts (n = 29021), a minimum of one CVE was detected. CVEs were associated with significantly more frequent hospital mortality (2.1% versus 1.0%; P < 0.01). The new models demonstrated good discriminative power, with an area under the receiver operating characteristic curve (AUC) of 0.709 and 0.707 respectively. Discrimination of the ASA classification (AUC 0.647) and the RCRI (AUC 0.620) were less. Neither the two new models nor ASA classification nor the RCRI showed acceptable calibration. ASA classification and the RCRI alone both proved unsuitable for the prediction of intraoperative CVEs.

IMPLICATIONS

The objective of this study was to evaluate prognostic models for quality assurance purposes to predict the occurrence of automatically detected intraoperative cardiovascular events in 58,458 patients undergoing noncardiac surgery. Two newly developed models showed good discrimination but, because of reduced calibration, their clinical use is limited. The ASA physical status classification and the Revised Cardiac Risk Index are unsuitable for the prediction of intraoperative cardiovascular events.

Perioperative management and monitoring in anaesthesia

In recent years, several risk factors for adverse outcome in patients undergoing anaesthesia have been identified. Besides human errors, cardiovascular and respiratory complications are associated with substantial morbidity. Assessment of complications has promoted the introduction of basic physiological monitoring in clinical practice. Whether monitoring directly affects outcome is not proven; however, circumstantial evidence suggests that basic cardiorespiratory monitoring decreases the incidence of serious accidents. Prevention of hypothermia also reduces anaesthesia-related morbidity. Measurement of body temperature is mandatory, and active warming is a simple, effective technique to avoid hypothermia. Evidence is growing that patients with known or suspected coronary artery disease should be treated with beta blockers perioperatively. Whether the type of anaesthesia-ie, general or regional-is relevant to perioperative mortality remains unclear. In subgroups of patients at high risk, neuraxial anaesthesia reduces the rate of respiratory and cardiovascular complications.

Role of history and physical examination in preoperative evaluation

BACKGROUND AND OBJECTIVE

Since reports have shown that outpatient preoperative evaluation increases the quality of care and cost-effectiveness, an increasing number of patients are being evaluated purely on an outpatient basis. To improve cost-effectiveness, it would be appealing if those patients who are healthy and ready for surgery without additional testing could be easily distinguished from those who require more extensive evaluation. This paper examines whether published studies provide sufficient data to determine how detailed preoperative history taking and physical examination need to be in order to assess the health of surgical patients and to meet the objective of easy and early distinction.

METHODS

A MEDLINE search was conducted from 1991 to 2000 with respect to preoperative patient history and physical examination. Altogether, 213 articles were found, of which 29 were selected. Additionally, 38 cross-references, 7 articles on additional testing and 4 recently published papers were used.

RESULTS

It is questionable to what extent an extensive history is relevant for anaesthesia and long-term prognosis. With respect to physical examination, it seems unreasonable to diagnose valvular heart disease based on cardiac auscultation only, and it is unclear which method should be used to predict the difficulty of endotracheal intubation. The benefits of routine testing for all surgical patients before operation are extremely limited and are not advocated.

CONCLUSIONS

The amount of detail of preoperative patient history and the value of physical examination to obtain a reasonable estimate of perioperative risk remains unclear. Although not evidence based, a thorough history taking and physical examination of all patients before surgery seems important until more evidence-based guidelines become available. Diagnostic and prognostic prediction studies may provide this necessary evidence.

Optimisation of oxygenation and tissue perfusion in surgical patients

Surgical patients with limited cardiovascular reserve have much worse prognosis than patients with normal hearts. This review identifies 17 randomised controlled clinical trials that have investigated peri-operative therapy designed to increase tissue perfusion in surgical patients, many of whom have limited cardiovascular reserve. Although there are differences which make equating the trials complex, a total of 1974 patients have been enrolled in the studies and the odds ratio for reduction in mortality is 0.45 (95% confidence intervals 0.33-0.60). Further research needs to be undertaken in the identification of patients with limited cardiovascular reserve and for investigating proposed treatment strategies. Despite this, it appears that such patients have improved outcome if they are admitted to intensive care unit pre-operatively and have suitable therapy given to improve tissue oxygen delivery.

Anaesthesia and postoperative analgesia in older patients with chronic obstructive pulmonary disease: special considerations

Chronic obstructive pulmonary disease (COPD) and older age are known to be independent risk factors for severe perioperative adverse outcomes after surgery. A basic understanding of the disease, careful preoperative evaluation and preparation of the patient, as well as a tailored anaesthetic management plan might help to decrease complications in this patient population. Aging affects the pharmacokinetics and pharmacodynamics of almost all drugs and therefore the dosage must be adapted in older patients. The type of anaesthesia (general versus regional anaesthesia) has no substantial effect on perioperative morbidity and mortality. Most patients, even with severe COPD, tolerate general anaesthesia without major problems. One important goal of the anaesthetic management is to prevent reflex-induced bronchoconstriction, which can be accomplished by the use of volatile anaesthetics. Early recovery can be facilitated by the use of short-acting drugs, such as propofol and the new opioid remifentanil. Judicious use of neuromuscular blocking agents is necessary because of the risk of residual paralysis, and those agents associated with histamine liberation should be avoided. Ventilation requires long expiration times to avoid air trapping, and hyperinflation to avoid the possible threat of pneumothorax and a decrease in cardiac output. For postoperative analgesia, a balanced regimen consisting of regional analgesia with local anaesthetics and NSAIDs should be preferred. This will enhance analgesia and reduce opioid toxicity, which is important in patients with COPD, where respiratory depression is especially dangerous.

Intercurrent drug therapy and perioperative cardiovascular mortality in elective and urgent/emergency surgical patientst

The Oxford Record Linkage Study (ORLS; an epidemiological database) was used to examine relationships between intercurrent cardiovascular drug therapy and cardiac death within 30 days of elective or emergency/urgent surgery under general anaesthesia. Cases identified from the ORLS were paired with matched control patients. Clinical details were obtained from the patients' medical notes. In elective surgical patients, there was no effect of beta-adrenoceptor or calcium entry channel blockade, diuretics or digoxin on cardiac death after adjusting for confounding variables. Use of nitrates was associated with an odds ratio of 4.79 [95% confidence interval (CI) 1.01-22.72] for cardiac death after adjustment for confounding by a history of angina and residual age difference. In emergency/urgent patients, there were significant univariate associations with cardiac death for intercurrent use of angiotensin converting enzyme (ACE) inhibitors (odds ratio 1.18) and diuretics (odds ratio 4.95; 95% CI 1.82-13.46). However, neither maintained significance after adjustment for the confounding effect of cardiac failure. We conclude that, with the possible exception of the use of nitrates in elective surgical patients, chronic intercurrent drug treatment alone does not significantly affect the odds of cardiac death within 30 days of surgery.

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.

Serious co-morbidity among unselected cancer patients newly diagnosed in the southeastern part of The Netherlands in 1993-1996

The purpose of this study was to determine the prevalence of serious concomitant conditions at diagnosis among unselected patients with cancer, increasingly older in industrialized countries. About 34,000 newly diagnosed cancer patients were recorded in the Eindhoven Cancer Registry between 1993 and 1996; subsequently data on serious co-morbidity, classified according to the Charlson scheme (J Chron Dis 1987; 40: 373-383), were collected from the clinical records by registry personnel. Co-morbid conditions were present in 12% of adult patients below 45 years of age, 28% of those 45-59 years, 53% of those 60-74 years, and 63% of patients over 75 years of age, the prevalence being highest for patients with lung (58%), kidney (54%), stomach (53%), bladder (53%), and prostate cancer (51%). Males exhibited a 10% higher prevalence than females with similar tumors. Among patients over 60 years the most frequent conditions were heart and vascular diseases (ranging across the various tumors from 10% to 30%), hypertension (11-25%), another cancer (10-20%), COPD (chronic obstructive pulmonary disease) (3-25%), and diabetes mellitus (5-25%). Inclusion of frequent co-morbid conditions in prognostic research as well as the development of specific guidelines for patient care seems warranted.

Assessment of cardiovascular risks and overall risks for noncardiac surgery

Appropriate care of the elderly patient requires a concerted multi-disciplinary approach before, during, and after surgery to optimize functional outcomes, with the principal focus placed on improving quality of life and strategies for risk reduction. Perioperative physicians must be able to assess the biologic, not the chronologic, age of geriatric patients and their capacity for independent function. Physicians need to understand alterations in the physiology of elderly patients attributable to the normal aging process as well as the prevalence of concurrent pathologic conditions that necessitate special precautions. Maintaining autonomy and function as a result of an acute surgical intervention may be the most important outcome to the elderly patient. Most of the data available and guidelines promulgated do not specifically address the elderly population. It is important to collect data prospectively and use sophisticated methods for analyses to develop better management algorithms for these (often complicated) clinical issues in the elderly.

A cross-validated multifactorial index of perioperative risks in adults undergoing anaesthesia for non-cardiac surgery. Analysis of perioperative events in 26907 anaesthetic procedures

OBJECTIVE

To develop a severity index of anaesthetic risk that predicts relevant perioperative adverse events in adults.

DESIGN

Prospective cross-sectional study.

SETTING

Department of anaesthesiology at one university hospital.

PATIENTS

26907 consecutive anaesthetic procedures in patients over 15 years of age and a complete preoperative evaluation. Patients undergoing cardiac and obstetric surgery were excluded.

MEASUREMENTS AND MAIN RESULTS

Demographic data, preoperative health status, type of anaesthesia, operative procedures, and perioperative incidents (standardised on a national basis) were acquired by means of a computerised anaesthetic record system. Occurrence of at least one perioperative event with impact on postanaesthetic care was computed by a multivariate logistic regression model against 17 variables with different characteristics representing possible risk factors. Fourteen variables proved to be independent risk factors. The weighting of the variables was expressed in scores which added up to form a simple index for each patient. Patients without major risk factors (0-10 points) had a 0.3% risk of suffering from a relevant incident. Patients with more than 60 points had a 28.6% risk. The results were well demonstrated by cross-validation.

CONCLUSIONS

The index seems to reflect the risk of relevant perioperative incidents. It can be used for audit purposes. In daily routine, the index could focus our attention on patients with increased perioperative risk. However, it is limited in detecting particular constellations of factors which interact on each other with regard to perioperative risk.

Operations on patients deemed "unfit for operation and anaesthesia": what are the consequences?

BACKGROUND

The decision "patient unfit for anaesthesia and operation" is likely to cause a delay of the scheduled operation. This retrospective evaluation was done: 1) to determine the correctness of preoperative tentative diagnoses of coexisting diseases making anaesthesia and operation excessively risky in relation to the physician's training status; 2) to examine the question of whether preoperative medical management modified according to the anaesthesiologist's suggestions had a positive impact on the perioperative course.

METHODS

The medical records of patients scheduled for elective non-cardiac surgery who were rated "unfit for operation and anaesthesia" were evaluated. The accuracy of the tentative diagnoses was examined for relation to the training status of the anaesthesiologists. The preoperative management was tested for its impact on postoperative outcome.

RESULTS

During the observation period 16,122 patients underwent preoperative anaesthesiological assessment; 1021 (6.3%) were initially considered to be unfit for operation and anaesthesia. The records of 807 patients were available for review. The accuracy of the tentative diagnoses was 70%, and was not significantly affected by the training status of the physicians (P = 0.022). Four hundred and seventeen patients were excluded from the second part of the investigation (discharged without operation, underwent operation using local anaesthesia or tentative diagnosis not confirmed). Three hundred and ninety patients were operated under general anaesthesia. Group I (n = 216) was managed according to the anaesthesiologist's suggestions and was found to have a significantly lower complication rate (18.1%) than group II (n = 174) in which the suggestions from the preoperative assessment were ignored (32.2%; P < 0.05). The perioperative mortality rate in group I was 2.3% compared with 5.2% in group II (n.s.; P > 0.05).

CONCLUSIONS

We conclude that the anaesthesiology decision "patient unfit for operation and anaesthesia" has a high accuracy, independent of the anaesthesiologist's training status, and that preoperative medical management significantly reduces complications.

Comorbid conditions in old patients with femur fractures

BACKGROUND AND METHODS

The incidence of preexisting medical diseases (comorbid conditions) and their influence on the high rate of falls, associated severe injuries, operative treatment, and outcome including mortality rate, duration of hospitalization, and rehabilitation success was retrospectively evaluated in a group of 102 patients (mean age, 81 years; 81% women) with femoral fractures. A comparison of polymorbidity rates in a control group of 102 patients (mean age, 79 years; 86% women) with proximal humeral fractures was added.

RESULTS

The associated polymorbidity rate among patients with femoral fractures (FF) usually was statistically significantly higher than among patients with proximal humeral fractures (PHF) despite a comparable age and sex distribution: 80% of the patients with FF presented with cardiovascular (p < or = 0.001), 41% with pulmonary (p < 0.001), 67% with gastrointestinal (p < or = 0.001), 71% with neurologic (p < or = 0.001), 55% with urologic (p < or = 0.001), 75% with musculoskeletal (p < or = 0.1), and 61% with psychiatric (p < or = 0.001) disorders and complaints. Ninety percent of the patients used different medications (diuretics, cardiac agents, anticoagulants, antidiabetic agents, steroids, hypnotics, analgesics, psychotropic agents). The postoperative mortality rate was 11%, and the mean hospitalization period was 30 days. Forty-nine percent of the patients were discharged to their homes. Only 56% of the patients with PHF, however, presented with cardiovascular, 8% with pulmonary, 11% with gastrointestinal, 8% with neurologic, 9% with urologic, 64% with musculoskeletal, and 10% with psychiatric disorders.

CONCLUSION

The polymorbidity in the old patient probably is a major intrinsic cause of the high incidence of falls and associated severe femoral fractures. It influences the perioperative and postoperative medical and anesthesiologic treatment, the postoperative mortality rate, and the duration and success of the postoperative rehabilitation phase.

Perioperative respiratory events in smokers and nonsmokers undergoing general anaesthesia

BACKGROUND

The prevalence of respiratory diseases in smokers and nonsmokers and the incidence of perioperative respiratory events (PREs) were investigated for patients undergoing general anaesthesia. The aim was to quantify well-known problems and to identify possible new associations between smoking and PREs.

METHODS

From July 1992 to December 1994, risk factors, demographic data, and PREs were documented by an automatically readable anaesthetic record (ARAR). PREs were used as defined by the German Society of Anaesthesiology and Intensive Care.

RESULTS

Of 26961 subsequent anaesthesias in adults, 7122 (26.4%) were performed in smokers with a prevalence of chronic bronchitis of 23.3% (4.8% in nonsmokers). 1573 PREs occurred in 1397 (5.2%) of all anaesthetics. 459 events concerned intubation problems and problems in technical airway management. 1114 specific respiratory events (SPREs) like re-intubation, laryngospasm, bronchospasm, aspiration, hypoventilation/hypoxaemia and others had a total incidence of 5.5% in smokers and 3.1% in nonsmokers. The relative risk (RR) of SPREs was 1.8 in all smokers, 2.3 in young (16-39 years) smokers, and 6.3 in obese young smokers. The RR of perioperative bronchospasm was 25.7 in young smokers with chronic bronchitis.

CONCLUSION

The impact of smoking on perioperative respiratory problems should make anaesthetists take this widespread preoperative condition seriously, particularly in young adults. The presented method of incident reporting (based on a national classification) could contribute to future research in anaesthetic epidemiology.

Perianaesthetic management of patients with endocrine disease

Hyper- or hypofunctioning endocrine organs present a number of perianaesthetic challenges. This review covers some of the issues of perianaesthetic management of patients with primary or coexisting pathology of the following endocrine organs: The pancreas with diabetes mellitus as the most common endocrine cause of primary and secondary organ dysfunctions affecting anaesthetic care. Adrenal cortical pathology with excess or deficiency of adrenocortical hormones. Pheochromocytoma of the adrenal medulla with infrequent but challenging perianaesthetic problems. Thyroid gland diseases with hyper- or hypothyroidism. Parathyroid gland pathology with hypercalcaemia or hypocalcaemia. Disorders of the anterior and posterior pituitary gland. The carcinoid syndrome and more uncommon endocrinopathies such as adenomas from the gastroenteropancreatic endocrine tissues and the ovarian hyperstimulation syndrome are also reviewed briefly.

Comparison of propofol with isoflurane for maintenance of anesthesia in patients with chronic obstructive pulmonary disease: use of pulmonary mechanics, peak flow rates, and blood gases

Patients with chronic obstructive pulmonary disease (COPD) are usually anesthetized with an inhalation agent. After Institutional Review Board approval, informed consent was obtained from 60 patients with moderate to severe COPD according to a preoperative severity scoring system, which took into account history and objective findings. By using objective criteria, such patients were randomly assigned to receive propofol (group I) or isoflurane (group II) as primary maintenance agents. Preoperative and postoperative arterial blood gases, peak expiratory flow rates (PEFR), and chest X-rays were compared. Total dynamic compliance (CDYN) and V1 (% volume exhaled in first second) were measured using Pitot tube sidestream spirometry. A 1,000-mL super-syringe was used to measure total static compliance (CST). Measurements were recorded postintubation, midanesthesia, and pre-extubation. All patients received fentanyl, lidocaine, and propofol, 1.5 to 2.0 mg/kg, for induction. Succinylcholine, 1-1.5 mg/kg, was administered to facilitate intubation. Maintenance was with N2O-O2, vecuronium, and either propofol (n = 30) or isoflurane (n = 30). Both groups showed decreases in postoperative PaO2, SaO2, and PEFR (p < 0.05), but there were no differences between groups (p > 0.05). There were no significant chest X-ray differences. There were no differences between groups with respect to intraoperative pulmonary mechanics (p > 0.05). The only difference between groups was an increase in postoperative PaCO2 in group I and a decrease in group II (p < 0.05). Use of Pitot tube sidestream spirometry is a practical and noninvasive technique for monitoring pulmonary mechanics during anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)