Per Føge Jensen

Randomized evaluation of pulse oximetry in 20,802 patients. II: Perioperative events and postoperative complications

BackgroundThe authors describe the effect of pulse oximetry monitoring on the frequency of unanticipated perl-operative events, changes In patient care, and the rate of postoperative complications in a prospective randomized study. MethodsThe study Included 20,802 surgical patients in Denmark randomly assigned to be monitored or not with pulse oximetry In the operating room (OR) and postanesthesla care unit (PACU). ResultsDuring anesthesia and in the PACU, significantly more patients in the oximetry group had at least one respiratory event than did the control patients. This was the result of a 19-fold Increase in the incidence of diagnosed hypoxemia in the oximetry group than in the control group in both the OR and PACU (P < 0.00001). In the OR, cardiovascular events were observed In a similar number of patients in both groups, except myocardial ischemia (as denned by angina or ST-seg-ment depression), which was detected in 12 patients in the oximetry group and In 26 patients in the control group (P < 0.03). Several changes in PACU care were observed in association with the use of pulse oximetry. These Included higher flow rate of supplemental oxygen (P < 0.00001), Increased use of supplemental oxygen at discharge (P < 0.00001), and increased use of naloxone (P < 0.02). The rate of changes in patient care as a consequence of the oximetry monitoring Increased as the American Society of Anesthesiologists physical status worsened (P < 0.00001). One or more postoperative complications occurred in 10% of the patients in the oximetry group and in 9.4% in the control group (difference not significant). The two groups did not differ significantly in cardiovascular, respiratory, neurologic, or Infectious complications. The duration of hospital stay was a median of 5 days in both groups (difference not significant). An equal number of in-hospital deaths were registered in the two groups. Questionnaires, completed by the anesthesiologists at the five partlc

Randomized evaluation of pulse oximetry in 20,802 patients: I. Design, demography, pulse oximetry failure rate, and overall complication rate.

BackgroundAlthough pulse oximetry is currently In widespread use, there are few data documenting Improvement in patient outcome as a result of the use of oximetry. The authors describe the study design, patient demographic findings, data validation, pulse oximetry failure rate, and overall postoperative complication rates in the first large prospective randomized multicenter clinical trial on perloperative pulse oximetry monitoring. Methods;In five Danish hospitals, by random assignment, monitoring did or did not include pulse oximetry for patients 18 yr of age and older, whether scheduled for elective or emergency operations, or for regional or general anesthesia, except during cardiac and neurosurgical procedures. Operational definitions were established for perioperative events and postoperative complications. The data were collected preoperatively, during anesthesia, in the postanesthesia care unit, and until the day of discharge from the hospital or the seventh postoperative day. ResultsOf 20,802 patients, 10,312 were assigned to the oximetry group and 10,490, to the control group. In general, the demographic data, patient factors, and anesthetic agents used were distributed evenly. A slight intergroup difference was found in the distribution of age, duration of surgery, some types of surgery, and some types of anesthesia. The total failure rate of the oximetry was 2.5%, but it increased to 7.2% in patients with American Society of Anesthesiologists physical status 4 (P < 0.00001). In 14.9% of the patients, one or more events occurred in the operating room and 13.5% in the postanesthesia care unit. The overall postoperative complication rate was 9.7%. The total rates of cardiovascular and respiratory complications were 2.78% and 3.50%, respectively. Within the

Management of anaphylactic shock evaluated using a full-scale anaesthesia simulator

Background: The diagnosis of an anaphylactic reaction during anaesthesia is not the first consideration for the anaesthetist and might be missed. The aim of this study was to describe anaesthetists’ management of an anaphylactic reaction concerning diagnosing, treatment and application of anaesthesia crisis resource management (ACRM) in a full‐scale anaesthesia simulator.

Association of β-blocker therapy with risks of adverse cardiovascular events and deaths in patients with ischemic heart disease undergoing noncardiac surgery: a Danish nationwide cohort study.

IMPORTANCE Clinical guidelines have been criticized for encouraging the use of β-blockers in noncardiac surgery despite weak evidence. Relevant clinical trials have been small and have not convincingly demonstrated an effect of β-blockers on hard end points (ie, perioperative myocardial infarction, ischemic stroke, cardiovascular death, and all-cause death). OBJECTIVE To assess the association of β-blocker treatment with major cardiovascular adverse events (MACE) and all-cause mortality in patients with ischemic heart disease undergoing noncardiac surgery. DESIGN, SETTING, PARTICIPANTS, AND EXPOSURE: Individuals with ischemic heart disease with or without heart failure (HF) and with and without a history of myocardial infarction undergoing noncardiac surgery between October 24, 2004, and December 31, 2009, were identified from nationwide Danish registries. Adjusted Cox regression models were used to calculate the 30-day risks of MACE (ischemic stroke, myocardial infarction, or cardiovascular death) and all-cause mortality associated with β-blocker therapy. MAIN OUTCOMES AND MEASURES Thirty-day risk of MACE and all-cause mortality. RESULTS Of 28,263 patients with ischemic heart disease undergoing surgery, 7990 (28.3%) had HF and 20,273 (71.7%) did not. β-Blockers were used in 4262 (53.3%) with and 7419 (36.6%) without HF. Overall, use of β-blockers was associated with a hazard ratio (HR) of 0.90 (95% CI, 0.79-1.02) for MACE and 0.95 (0.85-1.06) for all-cause mortality. Among patients with HF, use of β-blockers was associated with a significantly lower risk of MACE (HR, 0.75; 95% CI, 0.70-0.87) and all-cause mortality (0.80; 0.70-0.92), whereas among patients without HF, there was no significant association of β-blocker use with MACE (1.11; 0.92-1.33) or mortality (1.15; 0.98-1.35) (P < .001 for interactions). Among patients without HF, β-blockers were also associated with a lowered risk among those with a recent myocardial infarction (<2 years), with HRs of 0.54 (95% CI, 0.37-0.78) for MACE and 0.80 (0.53-1.21) for all-cause mortality (P < .02 for interactions between β-blockers and time period after myocardial infarction), but with no significant association in the remaining patients. Results were similar in propensity score-matched analyses. CONCLUSIONS AND RELEVANCE Among patients with ischemic heart disease undergoing noncardiac surgery, use of β-blockers was associated with lower risk of 30-day MACE and mortality only among those with HF or recent myocardial infarction.

Time Elapsed After Ischemic Stroke and Risk of Adverse Cardiovascular Events and Mortality Following Elective Noncardiac Surgery

IMPORTANCE The timing of surgery in patients with recent ischemic stroke is an important and inadequately addressed issue. OBJECTIVE To assess the safety and importance of time elapsed between stroke and surgery in the risk of perioperative cardiovascular events and mortality. DESIGN, SETTING, AND PARTICIPANTS Danish nationwide cohort study (2005-2011) including all patients aged 20 years or older undergoing elective noncardiac surgeries (n=481,183 surgeries). EXPOSURES Time elapsed between stroke and surgery in categories and as a continuous measure. MAIN OUTCOMES AND MEASURES Risk of major adverse cardiovascular events (MACE; including ischemic stroke, acute myocardial infarction, and cardiovascular mortality) and all-cause mortality up to 30 days after surgery. Odds ratios (ORs) were calculated by multivariable logistic regression models. RESULTS Crude incidence rates of MACE among patients with (n = 7137) and without (n = 474,046) prior stroke were 54.4 (95% CI, 49.1-59.9) vs 4.1 (95% CI, 3.9-4.2) per 1000 patients. Compared with patients without stroke, ORs for MACE were 14.23 (95% CI, 11.61-17.45) for stroke less than 3 months prior to surgery, 4.85 (95% CI, 3.32-7.08) for stroke 3 to less than 6 months prior, 3.04 (95% CI, 2.13-4.34) for stroke 6 to less than 12 months prior, and 2.47 (95% CI, 2.07-2.95) for stroke 12 months or more prior. MACE risks were at least as high for low-risk (OR, 9.96; 95% CI, 5.49-18.07 for stroke <3 months) and intermediate-risk (OR, 17.12; 95% CI, 13.68-21.42 for stroke <3 months) surgery compared with high-risk surgery (OR, 2.97; 95% CI, 0.98-9.01 for stroke <3 months) (P = .003 for interaction). Similar patterns were found for 30-day mortality: ORs were 3.07 (95% CI, 2.30-4.09) for stroke less than 3 months prior, 1.97 (95% CI, 1.22-3.19) for stroke 3 to less than 6 months prior, 1.45 (95% CI, 0.95-2.20) for stroke 6 to less than 12 months prior, and 1.46 (95% CI, 1.21-1.77) for stroke 12 months or more prior to surgery compared with patients without stroke. Cubic regression splines performed on the stroke subgroup supported that risk leveled off after 9 months. CONCLUSIONS AND RELEVANCE A history of stroke was associated with adverse outcomes following surgery, in particular if time between stroke and surgery was less than 9 months. After 9 months, the associated risk appeared stable yet still increased compared with patients with no stroke. The time dependency of risk may warrant attention in future guidelines.

Dopamine, Dobutamine, and Dopexamine A Comparison of Renal Effects in Unanesthetized Human Volunteers

BackgroundRecently, dopexamine(DX), which acts via adrenergic (β2and dopaminergic DA1 receptors, has been introduced in the treatment of low cardiac output states. However, the renal effects of DX have not been compared to those produced by equipotent inotropic doses of dopamine (DA), which predominantly stimulates DA1 and DA2 receptors, and of do-butamine (DB), which stimulates β, but not DA receptors. The current study tested the null hypothesis that, with equal increases in cardiac output, DX, DA, and DB would have similar effects on renal function. MethodsEach drug was given for 2 h on three different occasions to eight normal subjects in doses adjusted to produce a similar 30–35% Increase in cardiac output. Effective renal plasma flow (ERPF) and glomerular filtration rate (GFR) were measured as renal clearances of l31I-hippuran and 99mTc-DTPA, respectively. Lithium clearance (CLI) was used as an Index of proximal tubular outflow. ResultsDoses of DA, DX, and DB were 2.90 ± 0.19, 1–00 ± 0.02, and 4.92 ± 0.40 μg · kg−1 · min−1 respectively. Dopamine and DX increased ERPF by 23% and 10%, respectively, whereas ERPF remained unchanged during DB. The Increase in ERPF was smaller during DX compared with DA. The GFR remained unchanged during DA and DB, but increased during DX (7%). The CLi Increased by 35% and 30% during DA and DX, respectively, but was not changed by DB. Calculated absolute proximal reabsorption rate (APR = GFR – CLi) decreased by 13% during DA, but remained unchanged during DB and DX. Dopamine Increased sodium clearance (CNa) by 103%, but the changes during DX and DB were not significant. Only DA decreased fractional distal reabsorption (FDRNa = 1 – CNa/CLi). ConclusionsThe findings are consistent with a specific, renal-vasodilating effect of DA and DX. However, in the current doses, this effect of DX was of lesser magnitude compared with that of DA. Only DA significantly Increased CNa, and the decreases In APR and FDRNa indicate that an effect on tubular reabsorption rate contributed to the natriuresis.

Treatment of ventricular fibrillation during anaesthesia in an anaesthesia simulator.

Background: To evaluate treatment of ventricular fibrillation (VF) occurring during anaesthesia and the use of a full–scale simulator, 80 anaesthetists in teams of two were attending a training session in the simulator Sophus.

Freunds adjuvant alone is antiatherogenic in apoE-deficient mice and specific immunization against TNFα confers no additional benefit

TNFalpha participates in the pathogenesis of atherosclerosis. The effect of immunization against TNFalpha on development of advanced vascular lesions in atherosclerosis-susceptible apoE-deficient mice was investigated. At 5-7 weeks of age, animals received immunization with either Freunds adjuvant and a recombinant antigenic TNFalpha molecule (TNF106), Freunds adjuvant alone, or no immunization. All mice received a Western-type high-fat diet for 12 weeks. Aortic sinus lesion area was determined by microscopic morphometry, the total aortic arch cholesterol content was determined by gas chromatography, and antibodies against TNFalpha, malondialdehyde-modified low density lipoprotein, or heat shock protein 60, were assessed by ELISAs. Immunization with TNF106 induced high-titered circulating antibodies against TNFalpha (n=23), and these antibodies were not detected in mice immunized with Freunds adjuvant alone (n=22), or in non-immunized control animals (n=25). After 12 weeks, the atherosclerotic lesion size was significantly reduced in immunized animals, whether they had been immunized with TNF106 or Freunds adjuvant alone, and the total lesional cholesterol content was decreased in mice immunized with TNF106. There were no correlations between circulating antibody titers and plaque size, total aortic arch cholesterol content, or plasma lipid levels, respectively. Administration of Freunds adjuvant alone can thus reduce formation of mature atherosclerotic lesions in apoE-deficient mice and this response is not modified by specific immunization against TNFalpha.

How do anaesthesiologists treat malignant hyperthermia in a full‐scale anaesthesia simulator?

Background: Clinical malignant hyperthermia (MH) is rare and usually occurs unexpectedly. Prompt diagnosis and correct treatment is crucial for survival of the patient developing fulminant MH. The aims of the present study were to investigate whether anaesthesiologists could make a correct diagnosis of MH and to evaluate their treatment of fulminant MH in a simulator.

The Sophus anaesthesia simulator v. 2.0. A Windows 95 control-center of a full-scale simulator.

The Sophus group was founded in Denmark in 1992 with the aims of doing research into human error in anaesthesiology. Development of a simulation-environment was seen as one of the tools for research and training. This article describes the PC user interface of the SOPHUS anaesthesia simulator, SOPHUS v. 2.0 for Windows 95, and the script language, SASL v. 1.2. The script language provides possibilities of making scenarios, which develop in different directions according to the treatment of the patient by means of IF/THEN-statements, loops etc.