Operating unit time use is associated with anaesthesia type in below-knee surgery in adults.

BACKGROUND: Peripheral nerve blocks could reduce the operating unit and theatre time spent on high-risk patients who are particularly vulnerable to complications of general anaesthesia or have medications that prevent application of central neuraxial blocks. METHODS: Medical record data of 617 and 254 elderly adults undergoing below-knee surgery in Jorvi and Meilahti hospitals (Helsinki University Hospital) between January 2010 and December 2012 were used to investigate the influence of anaesthetic technique on operating theatre times and on operating unit times using flexible parametric survival models. We report operating theatre and unit exit ratios (i.e. hazard ratios but using ratios of exit rates) for different types of anaesthesia. RESULTS: Adjusted analyses: In Jorvi Hospital, anaesthesia type was associated with large initial differentials in operating theatre times. The theatre exit ratios remained lower for general anaesthesia and central neuraxial blocks compared to peripheral nerve blocks until 30 min. In Meilahti Hospital, anaesthesia type did not influence theatre time, but was the best predictor of operating unit times. Compared to peripheral nerve blocks, the exit ratio remained lower for general anaesthesia until five operating unit hours in both hospitals and for central neuraxial blocks until 1 h in Meilahti Hospital and until 3 h in Jorvi Hospital. Holding area was used more in Jorvi Hospital compared to Meilahti Hospital. CONCLUSION: Peripheral nerve block anaesthesia reduces time spent in the operating unit and can reduce time spent in the operating theatre if induced in holding area outside of theatre.

Dexamethasone decreases oxycodone consumption following osteotomy of the first metatarsal bone: a randomized controlled trial in day surgery.

BACKGROUND: Dexamethasone may improve multimodal pain management following painful orthopedic day surgery procedures, and decrease the need for post-operative opioids. We hypothesized that dexamethasone would reduce the need for oxycodone after surgical correction of hallux valgus. METHODS: Sixty patients planned to undergo unilateral osteotomy of the first metatarsal as a day surgery procedure were randomized to receive pre-operatively and 24 h afterwards, orally either dexamethasone 9 mg or placebo. For pain medication, paracetamol and oxycodone capsules for rescue medication were given. The study ended on the evening of the third post-operative day (POD). The primary endpoint was the cumulative oxycodone consumption. Secondary endpoints were maximal pain scores before oxycodone intake and daily oxycodone doses. In addition, adverse effects were documented. RESULTS: Twenty-five patients in both groups completed the study. The total median (range) oxycodone consumption during the study period was 45 (0-165) mg in the dexamethasone group and 78 (15-175) mg in the placebo group (P=0.049). The major differences in oxycodone consumption were seen on PODs 0-1. In the dexamethasone group, patients reported significantly lower pain scores on PODs 0-1, and significantly less nausea on POD 1. On PODs 2-3 no differences were seen. However, at 2 weeks post-operatively, patient satisfaction to drug therapy did not differ - in both groups 81% would have chosen the same medication again. CONCLUSION: Oral dexamethasone combined with paracetamol significantly reduced total oxycodone consumption following surgical correction of hallux valgus.

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.

Day surgery in Finland: a prospective cohort study of 14 day-surgery units.

BACKGROUND: Day surgery is an established practice for elective operative care, and is considered safe and cost-effective in several procedures and for several patients. At present, day-surgery accounts for approximately 50% of elective surgery in Finland. The aim of this study was to prospectively describe the present situation at Finnish day-surgery units, focusing on the quality of care. METHODS: Fourteen large- to medium-sized day surgery and short-stay units were recruited, and all patient cases performed during a 2-month study period were registered and analyzed. Quality of care was assessed by analyzing the rates and reasons for overnight admission, readmission, reoperation, and cancellations. Satisfaction of care was inquired from day-surgery patients during a 2-week period. Head anesthesiologists were interviewed about functional policies. RESULTS: Of 7915 reported cases, 84% were day surgery. Typically, several specialties were represented at the units, with orthopedics accounting for nearly 30% of all day-surgery procedures. Patient selection criteria were in line with the present-day recommendations, although the proportion of older patients and the ASA physical status 3 patients were still relatively low. The rate of unplanned overnight admissions was 5.9%. Return hospital visits were reported in 3.7% and readmissions in 0.7% of patients 1-28 days post-operatively. Patient satisfaction was high. CONCLUSION: Along with the growing demand for day surgery, Finnish public hospitals have succeeded in providing good-quality care, and there still seems to be potential to increase the share of day surgery. Easily accessible benchmarking tools are needed for quality control and learning from peers.

Surgical stress index as a measure of nociception/antinociception balance during general anesthesia.

BACKGROUND: No validated monitoring method is available for evaluating the nociception/antinociception balance. We assessed the surgical stress index (SSI), computed from finger photoplethysmographic waveform amplitudes and pulse-to-pulse intervals, in patients undergoing shoulder surgery under general anesthesia (GA) and interscalene plexus block and in patients with GA only. METHODS: In this prospective, randomized study in 26 patients, increased blood pressure (BP) or heart rate, movement, and coughing were considered to be signs of intraoperative nociception and were treated with alfentanil. GA was maintained with desflurane aiming at a State Entropy level of 50. Photoplethysmographic waveforms were collected from the contra-lateral arm to the surgery and SSI values from 0 (no surgical stress) to 100 (maximal surgical stress) were calculated off-line. RESULTS: Two minutes after skin incision, SSI had not increased in the plexus group and was lower in the plexus group (38 +/- 13) compared with the controls (58 +/- 13, P<0.005). Among the controls, 1 min before alfentanil administration, the SSI value was higher than during periods of adequate antinociception, 59 +/- 11 vs. 39 +/- 12 (P<0.01). The total cumulative need for alfentanil was higher in controls (2.7 +/- 1.2 mg) compared with the plexus group (1.6 +/- 0.5 mg; P=0.008). Tetanic stimulation to the ulnar region of the hand increased SSI significantly only among the patients with plexus block not covering the site of the stimulation. CONCLUSION: SSI values were lower in patients with plexus block covering the sites of nociceptive stimuli. In detecting nociceptive stimuli, SSI had better performance than heart rate, BP, or response entropy.

Therapeutic hypothermia after cardiac arrest: implementation and outcome in Finnish intensive care units.

BACKGROUND: Therapeutic hypothermia (TH) has been shown to increase survival after out-of-hospital resuscitation. The aim of our study was to find out nationwide implementation and the actual utilization of TH after cardiac arrest in Finnish intensive care units (ICUs). We also determined the outcomes and describe demographic variables of the patients treated with TH. METHODS: We analyzed a nationwide prospective database and included all adult patients (1,555) treated in ICUs after cardiac arrest during 2004 and 2005. RESULTS: During 2004 and 2005, 407 patients were treated with TH and TH was used in 19 out of the 20 ICUs. The proportion of cardiac arrest patients treated with TH had increased from 4% in 2002 to 28% in 2005. The incidence of cardiac arrest patients admitted to ICUs was 15/100,000 inhabitants/year. The use of TH varied in different areas of the country from 3.4 to 5.0/100,000 inhabitants/year. In-hospital mortality of TH patients was 32.7% and increased from 13.2% in age group <45 years to 46.0% in age group >75 years (P = 0.0002). Six-month survival was 55.3%. Median (interquartile range) length of stay in the ICU was 3.7 (2.7-5.3) days. CONCLUSION: In Finland, TH is implemented in almost all ICUs but it is applied only to a selected group of patients. Six months after cardiac arrest, more than half of the patients treated with TH were alive. Among patients treated with TH, younger patients had lower in-hospital mortality.

Auditory-evoked potentials in bispectral index-guided anaesthesia for cardiac surgery.

BACKGROUND AND OBJECTIVE: Midlatency auditory-evoked potentials, as measures of the anaesthetic state, were evaluated at similar levels of bispectral index in cardiac surgical patients maintained with either propofol or isoflurane anaesthesia. METHODS: Twenty-four patients were randomly allocated to anaesthesia with propofol (n = 12) or isoflurane (n = 12). Bispectral index was maintained below 60 during surgery. Auditory-evoked potentials were collected before induction of anaesthesia, 10 min after intubation, 30 min after sternotomy, during cardiopulmonary bypass at the time of cross-clamping of the aorta and during stable mild hypothermia, after de-clamping of the aorta, and after the operation. RESULTS: At the pre-determined time points, bispectral index values showed comparable depth of hypnosis in both groups. The latency of the Nb component of midlatency auditory-evoked potentials was significantly increased in the isoflurane group after intubation (P < 0.001) and that of both the Nb and the Pa components after sternotomy (P < 0.001) compared with the propofol group. No differences between the groups were detected with respect to haemodynamic variables. No patient reported recall of intraoperative events. CONCLUSION: After intubation and surgical stimulation, when bispectral index was at a constant level, there was a difference in the Nb and Pa components of the midlatency auditory-evoked potentials between the two anaesthetic regimens, indicating a distinction in the state of anaesthesia. Our results suggest that the parallel use of these two electrophysiological methods can show differences in the components of anaesthesia between various anaesthesia methods in cardiac surgical patients.

Supplemental 80% oxygen does not attenuate post-operative nausea and vomiting after breast surgery.

BACKGROUND: Although supplemental oxygen has been shown to be as effective as ondansetron in the prevention of post-operative nausea and vomiting (PONV) in one study in abdominal surgery patients, the antiemetic efficacy of supplemental oxygen is controversial on the basis of studies with other patients. We compared the efficacy of 80% and 30% oxygen in decreasing PONV in breast surgery. Ondansetron was used as an active control. METHODS: Ninety patients were given a standardized sevoflurane anesthetic. They were randomly assigned to three groups: 30% oxygen in nitrogen and saline 2 ml intravenously (i.v.) at the end of surgery (group 30); 80% oxygen in nitrogen and saline 2 ml (group 80); and 30% oxygen in nitrogen and ondansetron 4 mg (group O). Oxygen was administered during surgery and up to 2 h after surgery. RESULTS: The incidence of total response (no retching or vomiting, no nausea) during the first 24 post-operative hours was not different between group 80 (17%) and group 30 (11%) but was higher in group O (43%) than in group 30 (P<0.05). Compared with group O, patients in group 80 experienced more vomiting during the study period 0-24 h (66% vs. 32%; P<0.05) and more nausea during the period 6-24 h (72% vs. 39%; P<0.05). There was no difference between the groups in their risk for PONV, pain scores, opioid consumption, or patient satisfaction. CONCLUSIONS: In this study, supplemental 80% oxygen administration failed to decrease PONV in breast surgery.

Recovery of N100 component of auditory event-related potentials and EEG after cardiac arrest during propofol sedation.

We report on the EEG monitoring of a patient who suffered an episode of postoperative ventricular fibrillation (VF) following coronary artery bypass grafting (CABG). VF initially caused a considerable suppression and slowing of the EEG. The recovery of cerebral function was evaluated by recording both EEG and auditory event related potentials (ERPs). Six hours after the episode of VF, when the patient was asleep but arousable to voice command, the N100 component of the auditory ERPs had recovered to the level measured before the operation, whereas the EEG was still very slow for that level of sedation. This may have been due to VF having less effect on the N100 component than on the background EEG. Our findings suggest that measuring evoked potentials may improve the evaluation of brain function after cardiac arrest.

Airway pressure release ventilation as a primary ventilatory mode in acute respiratory distress syndrome.

BACKGROUND: Airway pressure release ventilation (APRV) is a ventilatory mode, which allows unsupported spontaneous breathing at any phase of the ventilatory cycle. Airway pressure release ventilation as compared with pressure support (PS), another partial ventilatory mode, has been shown to improve gas exchange and cardiac output. We hypothesized whether the use of APRV with maintained unsupported spontaneous breathing as an initial mode of ventilatory support promotes faster recovery from respiratory failure in patients with acute respiratory distress syndrome (ARDS) than PS combined with synchronized intermittent ventilation (SIMV-group). METHODS: In a randomized trial 58 patients were randomized to receive either APRV or SIMV after a predefined stabilization period. Both groups shared common physiological targets, and uniform principles of general care were followed. RESULTS: Inspiratory pressure was significantly lower in the APRV-group (25.9 +/- 0.6 vs. 28.6 +/- 0.7 cmH2O) within the first week of the study (P = 0.007). PEEP-levels and physiological variables (PaO2/FiO2-ratio, PaCO2, pH, minute ventilation, mean arterial pressure, cardiac output) were comparable between the groups. At day 28, the number of ventilator-free days was similar (13.4 +/- 1.7 in the APRV-group and 12.2 +/- 1.5 in the SIMV-group), as was the mortality (17% and 18%, respectively). CONCLUSION: We conclude that when used as a primary ventilatory mode in patients with ARDS, APRV did not differ from SIMV with PS in clinically relevant outcome.

Supplemental oxygen for prevention of nausea and vomiting after breast surgery.

BACKGROUND: Administration of supplemental oxygen 80% has been shown to halve the incidence of postoperative nausea and vomiting (PONV). We tested the efficacy of supplemental oxygen 50% in decreasing the incidence of PONV after breast surgery. METHODS: One hundred patients receiving standardized sevoflurane anaesthesia were randomly assigned to two groups: oxygen 30% administration (Group 30); and oxygen 50% administration (Group 50). Oxygen was administered during surgery and for 2 h from the end of surgery. RESULTS: The incidence of PONV over 24 h after surgery showed no difference between the groups: 82% in Group 30 and 89% in Group 50. However, during the postoperative oxygen administration, eight patients vomited in Group 30, compared with none in Group 50 (P<0.05). After oxygen therapy ceased, there was no difference in the incidence of vomiting between the groups. Nausea and need for rescue antiemetics did not differ between the groups. CONCLUSION: The incidence of vomiting decreased during the short postoperative administration of supplemental oxygen 50%. However, perioperative oxygen 50% administration did not prevent PONV over the 24-h follow-up period in patients undergoing breast surgery performed under general anaesthesia.

Customized prediction models based on APACHE II and SAPS II scores in patients with prolonged length of stay in the ICU.

OBJECTIVE: To study customized APACHE II and SAPS II models in predicting hospital death in patients with a prolonged length of stay in the ICU. DESIGN: Prospectively collected database. SETTING: Thirteen ICUs with 5-10 beds in Finnish secondary referral hospitals. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: The database was collected between 1994 and 1999 and included 23,953 ICU admissions. In order to customize the original APACHE II and SAPS II models and to validate the models, the database was randomly divided into customization data ( n=12,064) and into validation data ( n=11,889). Logistic regression analysis was used for customization. As the length of the ICU stay was prolonged, the calibration and discrimination of both customized models worsened gradually in the validation data. Patients whose ICU stay lasted 7 days or longer (1,312 patients) consumed more than one half of all ICU days and TISS-points. Among these patients, goodness-of-fit statistics was 221.5 and 306.3 ( P<0.0001 for both) and the areas under ROC curve 0.65 and 0.62 for the customized APACHE and SAPS models, respectively. The models underestimated the risk of death in the low range and overestimated it in the high range of predicted mortality. On the other hand, both models discriminated well between survivors and non-survivors if the ICU stay was 2 days or less. CONCLUSIONS: Despite customization, the predictive models may not support clinical decision-making in those patients who require a high share of resources. More relevant instruments are needed for the prediction of outcome of patient groups who consume the major part of ICU resources.

Intra-institutional prediction of outcome after cardiac surgery: comparison between a locally derived model and the EuroSCORE.

OBJECTIVE: To construct models for predicting mortality, morbidity and length of intensive care unit (ICU) stay after cardiac surgery and to compare the performance of these models with that of the EuroSCORE in two independent validation databases. METHODS: Clinical data on 4592 cardiac surgery patients operated between 1992 and 1996 were retrospectively collected. In order to derive predictive models and to validate them, the patient population was randomly divided into a derivation database (n=3061) and a validation database (n=1531). Variables that were significant in univariate analyses were entered into a backward stepwise logistic regression model. The outcome was defined as mortality within 30 days after surgery, predefined morbidity, and the length of ICU stay lasting >2 days. In addition to the retrospective database, the models were validated also in a prospectively collected database of cardiac surgical patients operated in 1998-1999 (n=821). The EuroSCORE was tested in two validation databases, i.e. the retrospective and prospective one. Hosmer-Lemeshow goodness-of-fit was used to study the calibration of the predictive models. Area under the receiver operating characteristic (ROC) curve was used to study the discrimination ability of the models. RESULTS: The overall mortality in the retrospective and the prospective data was 2 and 1%, and morbidity 22 and 18%, respectively. The created predictive models fitted well in the validation databases. Our models and the EuroSCORE were equally good in discriminating patients. Thus, in the prospective validation database, the mean areas under the ROC curve for our models and for the EuroSCORE were similar, i.e. 0.84 and 0.77 for mortality, 0.74 and 0.74 for morbidity, and 0.81 and 0.79 for the length of intensive care unit stay lasting for 2 days or more, respectively. CONCLUSIONS: Our models and the EuroSCORE were equally good in discriminating the patients in respect to outcome. However, our model provided also well calibrated estimation of the probability of prolonged ICU stay for each patient. As was originally suggested, the EuroSCORE may be an appropriate tool in categorizing cardiac surgical patients into various subgroups in interinstitutional comparisons. Our models may have additive value especially in resource allocation and quality assurance purposes for local use.

Comparison of alfentanil, fentanyl and sufentanil for total intravenous anaesthesia with propofol in patients undergoing coronary artery bypass surgery.

We have studied the pharmacokinetics and pharmacodynamics of alfentanil, fentanyl and sufentanil together with propofol in patients undergoing coronary artery bypass graft surgery (CABG). Sixty patients (age 40-73 yr, 56 male) were assigned randomly to receive alfentanil, fentanyl or sufentanil and propofol. Plasma concentrations of these drugs and times for the plasma concentration to decrease by 50% (t50) and 80% (t80) after cessation of the infusion were determined. Times were recorded to awakening and tracheal extubation. Total dose and plasma concentrations of propofol were similar in all groups. Mean total doses of alfentanil, fentanyl and sufentanil were 443, 45 and 4.4 micrograms kg-1, respectively. Time to awakening did not differ significantly. In patients receiving fentanyl, the trachea was extubated on average 2 h later than in those receiving sufentanil and 3 h later than in those receiving alfentanil (P < 0.05). The t80 of fentanyl was longer (P < 0.05) than that of alfentanil or sufentanil, and there was a linear correlation between the t80 of the opioid and the time to tracheal extubation (r = 0.51; P < 0.01). However, the t50 values for these opioids were similar and did not correlate with recovery time. In conclusion, patients undergoing CABG and who were anaesthetized with fentanyl and propofol needed mechanical ventilatory support for a significantly longer time than those receiving alfentanil or sufentanil and propofol. On the basis of the interindividual variation observed, the time to tracheal extubation was most predictable in patients receiving alfentanil and most variable in patients receiving fentanyl, a finding which may be important if the patients are transferred to a step-down unit on the evening of the operation.

Coating of extracorporeal circuit with heparin does not prevent sequestration of propofol in vitro.

Propofol is sequestered in extracorporeal circuits, but the factors responsible for the phenomenon are mostly unknown. We have compared two extracorporeal circuits (oxygenators, reservoirs and tubings) coated with heparin with two corresponding uncoated circuits for their capacity to sequester propofol in vitro. Three experiments were conducted with each circuit. The circuit was primed with a mixture of Ringer's acetate solution and whole blood, and the study conditions (pump flow, temperature, pH) were standardized. Propofol was added to the solution to achieve a concentration of 2 micrograms ml-1. These studies were followed with concentrations of 10- and 100-fold to assess possible saturation of propofol binding. Serial samples were obtained from the circulating solution for measurement of propofol concentration. Propofol concentrations decreased to 22-32% of the initial predicted concentration of 2 micrograms ml-1 in the circuits (no significant difference between circuits). With greater concentrations, the circuits did not become saturated with propofol, even with the highest predicted concentration of 200 micrograms ml-1. We conclude that propofol was sequestered in extracorporeal circuits in vitro, irrespective of coating the circuit with heparin.

Effect of low-dose propofol infusion on total-body oxygen consumption after coronary artery surgery.

OBJECTIVE: To investigate the effect of low-dose propofol infusion on total-body oxygen consumption (VO2) after coronary artery bypass grafting (CABG) surgery. DESIGN: A prospective, randomized, placebo-controlled, double-blind study. SETTING: Cardiovascular intensive care unit in a university hospital. PARTICIPANTS: Thirty patients after elective, uncomplicated CABG surgery. INTERVENTION: Patients were administered a continuous infusion of propofol with a fixed rate of 1 mg/kg/h (n = 15) or placebo (n = 15) during the spontaneous rewarming period of approximately 5 hours after surgery. A light level of sedation (Ramsay sedation score > or =2) was maintained by administering small doses of diazepam, 0.1 mg/kg, as required. Morphine, 0.05 mg/kg, was administered for analgesia as required. MEASUREMENTS AND MAIN RESULTS: Total-body VO2 was measured by indirect calorimetry. In addition, shivering (on a five-grade scale), hemodynamics, and plasma catecholamine and serum cortisol concentrations were measured. Diazepam, 5.6+/-7.4 mg (mean +/- standard deviation), was administered to the patients receiving propofol, and 16.1+/-12.2 mg was administered to the patients receiving placebo (p < 0.05). There was no difference in the dose of morphine between the groups (3.2+/-3.9 v 4.2+/-5.5 mg in the propofol and placebo groups, respectively). At any time during the study, VO2 was not different between the groups. VO2 increased from 130+/-29 to 172+/-29 mL/min/m2 in the propofol group and from 118+/-24 to 167+/-27 mL/min/m2 in the placebo group. Mean arterial pressure and heart rate were lower in the propofol group (p < 0.05). Stress hormone levels did not differ between the groups. CONCLUSION: Low-dose propofol infusion and additional diazepam as required does not decrease total-body VO2 compared with a pure diazepam bolus-dose technique when administered for light sedation during the immediate recovery period after CABG surgery.