Institutional response to FDA warning on aprotinin and impact on outcomes.

INTRODUCTION: New evidence of potential risks of aprotinin in 2006 generated public concern about a previously approved drug that was routinely used. In response, we assembled a team of experts within the institution to form guidelines for the appropriate use of aprotinin in cardiac surgery. We report the basis for the guidelines, their implementation, follow-up and resulting patterns of change in aprotinin use. METHODS: We proposed a three-tier system for aprotinin use, according to risk of bleeding and transfusion, and evidence of benefit of aprotinin. Specific recommendations were made with regard to discussion with the patient and documentation regarding aprotinin use and options for patients who refuse the drug. Guidelines were disseminated and accessible on all anesthesia workstations. Aprotinin use was compared before and after institution of guidelines in equivalent categories.  RESULTS: Aprotinin was used in 58.5% (469/802) of cases from March 2005 to January 2006. Following institution of guidelines from March 2006 to January 2007, aprotinin was used in 19.7% (151/767) cases representing a 67.8% reduction in usage. In the subset of groups with large reductions in aprotinin use (pre- 82%, n=239; post-guidelines 17%, n=241) there was a significant decrease in acute kidney injury (%?Cr 43.8 vs. 31.7%, p=0.05). CONCLUSIONS: In response to new data and regulatory guidelines, we formulated guidelines based on expert review of data. We reduced aprotinin use, but more importantly, introduced an evidence-based approach to the use of aprotinin, consistent with regulatory guidelines. This model of guideline implementation can be useful in similar scenarios.

A descriptive study of the variation in baseline levels of antiendotoxin core antibodies between US and UK populations.

Low levels of naturally occurring antibodies to the core section of endotoxin (EndoCAb) have been shown to be predictors of poor outcome following major surgery. We performed a retrospective study comparing pre-operative levels in US surgical patients, UK surgical patients and healthy volunteers. Both IgM and IgG EndoCAb levels were higher in the US surgical patients when compared with the other groups (approximately twice as high in the case of IgG EndoCAb). This may reflect genetic or environmental variability between the patient groups, differences in the disease processes, the disparity in the delivery of health care between the two countries or degradation of the samples in transfer.

Endotoxaemia during left ventricular assist device insertion: relationship between risk factors and outcome.

BACKGROUND: Endotoxaemia, caused by splanchnic ischaemia during surgery, is believed to trigger systemic inflammation and cause postoperative organ dysfunction. A relationship between the plasma concentration of endotoxin during surgery and known risk factors for postoperative morbidity and mortality (e.g. age, abnormal gastric tonometric variables) and adverse outcome after surgery has not been demonstrated. METHODS: In a prospective study, the plasma concentration of endotoxin was measured in 12 patients undergoing implantation of a left ventricular assist device. Automated air gastric tonometry was performed in all patients. The relationship between plasma endotoxin concentration, risk factors, and postoperative outcome was explored. RESULTS: Carbon dioxide gap increased from 0.7 (0.3) to 3.6 (1.6) kPa at the end of surgery. Endotoxin was detected in one of 12 patients at baseline and in nine of 12 patients at the end of surgery (P=0.003). A high plasma concentration of endotoxin at the end of surgery was associated with a higher carbon dioxide gap (r=0.59, P<0.05), and a higher postoperative multiple organ dysfunction score (r=0.7, P=0.01). CONCLUSIONS: The finding of an association between high intraoperative plasma concentrations of endotoxin, abnormal gastric tonometric variables and adverse outcome supports the view that endotoxaemia is caused by gut hypoperfusion during surgery and is associated with postoperative organ dysfunction.

Comparison of P-POSSUM risk-adjusted mortality rates after surgery between patients in the USA and the UK.

BACKGROUND: The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) criteria have been used to assess surgical risk in patients in the UK. The aim was to determine how applicable these criteria are to patients undergoing surgery in the USA. METHODS: Two cohorts of patients undergoing major non-cardiac surgery were followed prospectively in the USA (n = 1056) and the UK (n = 1539). Each patient was assigned a risk score for preoperative physiological status and operative severity using the established POSSUM criteria. Death in hospital was the primary outcome measure. For each patient a predicted risk of death was calculated from Portsmouth POSSUM (P-POSSUM) methodology using an established equation. The relationships between predicted and observed mortality rates in each cohort were investigated by means of multivariate logistic regression. RESULTS: Within each cohort, an increase in risk estimated by P-POSSUM predicted an increase in observed mortality rate (P < 0.001). For any given risk level, however, mortality rates were significantly higher in the UK cohort than in the US cohort (odds ratio 4.50 (95 per cent confidence interval 2.81 to 7.19); Z = 6.25, P < 0.001). CONCLUSION: An increase in predicted risk, based on the P-POSSUM methodology, was associated with a higher mortality rate in patients from both countries. However, risk-adjusted mortality rates following major surgery were four times higher in the UK cohort. These marked differences warrant validation in a larger number of centres.

Validation of continuous thermodilution cardiac output in patients implanted with a left ventricular assist device.

OBJECTIVE: To assess the accuracy of a continuous cardiac output (CCO) monitor against an independent, intravascular measurement of flow as can be performed in patients fitted with a left ventricular assist device (LVAD). DESIGN: A prospective cohort study. SETTING: Academic tertiary-care center. PARTICIPANTS: Adult patients (n = 15) presenting for LVAD placement. INTERVENTIONS: Consenting patients presenting for LVAD placement for end-stage cardiac failure were anesthetized, and a CCO pulmonary artery catheter was placed (OptiQ, CCO/SvO(2); Abbott Critical Care, North Chicago, IL). Patients were monitored with transesophageal echocardiography and excluded from analysis if aortic regurgitation was found. Cardiac output was determined using a Q-Vue, CCO/SvO(2) computer with digital readout (Abbott Critical Care, North Chicago, IL). The LVAD was placed in standard fashion during cardiopulmonary bypass. The Thoratec vented electric Heartmate (Thoratec Co, Pleasanton, CA) incorporates an LVAD flow console, which computes LVAD flow within +/- 5% (range, 1.8 to 10 L/min). MEASUREMENTS AND MAIN RESULTS: Cardiac output flow measurements were made from both systems at the following time points: 5 minutes and 30 minutes after protamine administration, at chest closure, and after skin closure. Mean cardiac output for each device did not differ at any time point. Regression analysis (Pearson's) showed acceptable correlation (r(2) = 0.79, p < 0.0001), whereas a bias of 529 mL with limits of agreement of 1,208 mL were shown for CCO measurement compared with LVAD flow. CONCLUSION: The data indicate that the CCO system tends to overestimate cardiac output by approximately 500 mL/min when compared with LVAD flow. Nevertheless, this bias is within the range found by other less-invasive studies done to assess the accuracy of this system and further serves to confirm its relative accuracy.

The impact of newly diagnosed patent foramen ovale in patients undergoing off-pump coronary artery bypass grafting: case series of eleven patients.

UNLABELLED: The increased use of transesophageal echocardiography (TEE) by anesthesiologists may lead to an increase in the intraoperative detection of previously undiagnosed patent foramen ovale (PFO). The impact of heart manipulation on interatrial shunting through a PFO during off-pump coronary artery bypass graft (CABG) has not been studied. We retrospectively studied 11 patients with PFOs who underwent off-pump CABG. TEE contrast studies and blood gas analyses were performed at baseline, during heart elevation for distal coronary arteries anastomoses, and at the end of the surgery. At baseline, 5 of 11 patients had left-to-right shunting and 2 of 11 had right-to-left shunting. Heart elevation did not result in oxygen desaturation in any patient; however, it caused the disappearance of a right-to-left shunt (n = 1), persistence of this shunt (n = 1), and the development of a new right-to-left shunt (n = 2). Return of the heart to its original position resulted in a return of TEE findings to the baseline state in all patients. This series suggests that off-pump CABG can be performed safely in the majority of patients with PFOs; however, additional investigation is needed to assure that adverse effects do not occur in a subset of patients undergoing off-pump CABG in the presence of a PFO. IMPLICATIONS: This case series suggests that coronary artery bypass graft surgery can be safely performed in most patients with patent foramen ovale without the use of a cardiopulmonary bypass.

A prospective, randomized comparison of thromboelastographic coagulation profile in patients receiving lactated Ringer's solution, 6% hetastarch in a balanced-saline vehicle, or 6% hetastarch in saline during major surgery.

OBJECTIVES: To compare the effects of lactated Ringer's solution (LR), 6% hetastarch in a balanced-saline vehicle (HS-BS), and 6% hetastarch in normal saline (HS-NS) on coagulation using thromboelastography. DESIGN: Prospective, randomized double-blinded evaluation of previously published clinical trial. SETTING: Tertiary-care medical center. PARTICIPANTS: Patients undergoing elective noncardiac surgery with an anticipated blood loss >500 mL. A total of 90 patients were enrolled with 30 patients in each group. INTERVENTIONS: Patients received a standardized anesthetic. LR, HS-BS, and HS-NS were administered intraoperatively based on a fluid administration algorithm. Hemodynamic targets included maintenance of arterial blood pressure, heart rate, and urine output within a predefined range. MEASUREMENTS AND MAIN RESULTS: Thromboelastography variables for r time, k time, maximum amplitude, and alpha angle (mean +/- SD) were recorded at induction of anesthesia, at the end of surgery, and 24 hours postoperatively. Patients in the LR group showed a state of hypercoagulation at the end of surgery with reductions (p < 0.005) in r time (-3.8 +/- 6.7 mm) and k time (-1.7 +/- 2.5 mm). This state of hypercoagulation continued into the postoperative period. Patients in the HS-NS group showed a state of hypocoagulation with increases (p < 0.05) in r time (+6.2 +/- 8.5 mm) and k time (+1.7 +/- 3.9 mm) and a reduction in maximum amplitude (-8.0 +/- 9.8 mm) at the end of surgery. This state of hypocoagulation was reduced in the postoperative period. Patients in the HS-BS group showed no significant changes in coagulation status at end of surgery, with the smallest changes in r time (-0.3 +/- 4.1 mm), k time (+0.1 +/- 3.1 mm), maximum amplitude (-5.4 +/- 12.3 mm), and alpha angle (0.3 +/- 12.5 degrees ). CONCLUSION: LR-treated patients exhibited a hypercoagulative profile that persisted into the postoperative period. HS-BS administration was associated with a lesser change in the coagulation profile compared with HS-NS, which was associated with a hypocoagulative state.

The effect of hypothermia on calculated values using saline and automated air tonometry.

OBJECTIVE: To quantify in vitro the effect of hypothermia on results obtained when performing automated air tonometry (Tonocap, Datex-Ohmeda, Instrumentarium Corp, Helsinki, Finland) and saline tonometry. DESIGN: In vitro validation study. SETTING: University hospital research laboratory. INTERVENTIONS: Two TRIP sigmoid catheters, one connected to the Tonocap device and the other instilled with 2.5 mL of 0.9% saline, were placed in a saline bath at 30.3 degrees C (mean) through which 5% carbon dioxide (CO(2)) was bubbled. MEASUREMENTS AND MAIN RESULTS: A total of 50 paired measurements were taken at 30-minute equilibration times of saline bath CO(2) tension and saline tonometry and air tonometry readings. Saline samples were analyzed at 37 degrees C and corrected for temperature. Bias and precision of each technique as a percentage of predicted CO(2) values were calculated. The Tonocap device had bias and precision values of -2.6% and +/-1.4%. Measurement of CO(2) is in the gaseous phase so that temperature correction is not required. Saline tonometry readings processed at 37 degrees C exhibited a large positive bias of 23.06% (precision +/- 7.02%). Correction for temperature improved bias to -10.98 % with a similar precision profile of +/-5.78%. CONCLUSION: When using gastrointestinal tonometry during hypothermic cardiopulmonary bypass, saline tonometry samples should be temperature corrected. The Tonocap device proved the most accurate and precise measurement technique independent of the need for temperature correction.

Preoperative and intraoperative predictors of postoperative morbidity, poor graft function, and early rejection in 190 patients undergoing liver transplantation.

HYPOTHESIS: Preoperative and intraoperative variables predict in part adverse outcome after liver transplantation. DESIGN: Prospective, blinded, cohort study. SETTING: Tertiary care hospital. SUBJECTS: A total of 190 adult patients undergoing primary liver transplantation. MAIN OUTCOME MEASURE: Adverse outcome was prospectively defined as either in-hospital death or prolonged postoperative hospitalization (>14 days) associated with morbidity. Potential preoperative and intraoperative risk factors were collected. Associations were tested by univariate analysis followed by multivariate analysis in which preoperative factors were entered before intraoperative factors. RESULTS: Adverse outcome occurred in 44.7% of patients. Incidences of other complications were as follows: in-hospital mortality (8.4%), primary graft nonfunction (4.2%), poor early graft function (1.1%), and early rejection (31.2%). Univariate predictors of adverse outcome were United Network for Organ Sharing status (P =.003), Child-Turcotte-Pugh score (P =.02), POSSUM physiological score (P =.002), recipient age (P =.01), preoperative serum high-density lipoprotein cholesterol level (P =.03), preoperative serum creatinine level (P =.002), preoperative serum total IgG level (P =.004), duration in hospital preoperatively (P =.03), operative duration (P<.001), allogeneic erythrocyte transfusions (P<.001), total intraoperative fluids (P =.002), and use of inotropic agents (P =.01). In the final multivariate model, predictors of adverse outcome were United Network for Organ Sharing status (P =.03), recipient age (P =.002), and total intraoperative fluids (P =.04). Most patients who died or had a prolonged hospitalization exhibited dysfunction of more than 1 organ system, including pulmonary, renal, and infectious complications. CONCLUSIONS: Adverse outcome occurs frequently after liver transplantation, usually involves multiple organ systems, and is predicted in part by several preoperative and intraoperative factors.

Endotoxin-neutralizing capacity of serum from cardiac surgical patients.

OBJECTIVE: To determine if endotoxin core antibody (EndoCAb) from the serum of cardiac surgical patients neutralizes endotoxin in an ex vivo biologic assay. DESIGN: Prospective blinded cohort study. SETTING: Academic medical center. PARTICIPANTS: Patients (n = 203) undergoing cardiac surgery. INTERVENTIONS: Sera were obtained from patients preoperatively. MEASUREMENTS AND MAIN RESULTS: EndoCAb levels were determined by enzyme-linked immunosorbent assay. Sera were incubated for 15 minutes at 37 degrees C with varying concentrations of endotoxin from a clinically relevant bacterium (Escherichia coli serotype O18), then tested for the presence of endotoxin activity using the validated Limulus amebocyte lysate assay. Median (interquartile range) IgM and IgG EndoCAb levels were 118 median units (range, 31 to 259 median units) and 208 median units (range, 108 to 401 medium units). Increasing levels of IgM EndoCAb were associated with increased neutralization of endotoxin (p < 0.0001). Increasing levels of IgG EndoCAb were associated with increased neutralization of endotoxin (p < 0.0001). An additive effect of IgM and IgG EndoCAb levels on endotoxin neutralization was observed without evidence of synergistic or plateau effects. EndoCAb levels did not completely predict serum neutralization capacity. CONCLUSION: Anti-EndoCAbs of both classes (IgM and IgG) were able to neutralize lipopolysaccharide from a clinically relevant bacterium in an ex vivo model. Neither Igm nor IgG appeared to be more capable of neutralization in this model. These antibodies did not completely predict neutralization capacity; other endogenous factors in human serum must be capable of lipopolysaccharide neutralization.

Arterial and venous Thrombelastograph variables differ during cardiac surgery.

UNLABELLED: The Thrombelastograph (TEG; Haemoscope Corp., Skokie, IL) coagulation analyzer is an effective point-of-care monitor for routine clinical practice and clinical research. Prior investigators have used either arterial or venous samples of blood for TEG measurements. We conducted this prospective cohort study to determine potential differences in TEG variables between arterial and venous blood samples. Arterial and venous samples were drawn from 40 cardiac surgical patients, yielding 134 pairs for comparison. Twenty-nine comparisons (control) were between arterial and arterial samples and were not significantly different. For the arterial and venous comparisons (n = 105), mean (+/-sd) arterial and venous values were the following: reaction time, 10 +/- 2 mm vs 13 +/- 4 mm, P = 0.004; maximum amplitude, 59 +/- 9 mm vs 49 +/- 12 mm, P < 0.001; alpha angle, 61 +/- 10 degrees vs 51 +/- 14 degrees, P < 0.001; K, 5 +/- 2 mm vs 8 +/- 4 mm, P = 0.007; and lysis, 2.5 +/- 1.7 vs 2.5 +/- 2.0 (not significant), arterial versus venous, respectively. Arterial blood samples demonstrated TEG values reflecting stronger (larger maximum amplitude) and faster (shorter reaction time and K value, wider alpha angle) clot formation. The results suggest that users of TEG coagulation analyzers should be consistent with the site of blood sampling given the potential differences obtained. IMPLICATIONS: Thrombelastograph (TEG) values obtained from venous blood samples differ from values obtained from arterial blood samples. When the TEG coagulation analyzer is used for clinical purposes, it is important to be consistent in the blood collection site.

Decreased endotoxin immunity is associated with greater mortality and/or prolonged hospitalization after surgery.

BACKGROUND: Patients undergoing noncardiac surgery often develop postoperative morbidity, potentially attributable to endotoxemia and the systemic inflammatory response syndrome. Endogenous antibodies to endotoxin may confer protection from endotoxin-mediated toxicity. The authors sought to determine the association of preoperative antiendotoxin immunity and death or prolonged hospitalization in a broad population of general surgical patients undergoing major surgery. METHODS: To test the hypothesis that low preoperative serum antiendotoxin core antibody (EndoCAb) concentration is an independent predictor of adverse outcome after general surgery, 1,056 patients undergoing routine noncardiac surgery were enrolled into a prospective, blinded, cohort study. Immunoglobulin M EndoCAb, immunoglobulin G EndoCAb, total inmunoglobulin M, and immunoglobulin G concentrations were measured in serum obtained preoperatively. A physiologic risk score using the established POSSUM criteria was assigned preoperatively to each patient. The primary predefined composite end point (postoperative complication) was either in-hospital death or postoperative length of stay greater than 10 days. Multivariate logistic regression was used to test the study hypothesis. RESULTS: Overall, postoperative complication occurred in 234 of the 1,056 patients (22.1%). Lower immunoglobulin M EndoCAb concentration (P = 0.006) predicted increased risk of postoperative complication independent of POSSUM physiologic risk score (P < 0.001). In contrast, total immunoglobulin M and total immunoglobulin G concentrations did not predict adverse outcome. Complications involved multiple organ systems and were generally unrelated to the type or site of surgery, consistent with the systemic inflammatory response syndrome. CONCLUSIONS: Adverse outcome after routine noncardiac surgery is common and is predicted in part by low concentrations of EndoCAb. The authors' findings suggest that endotoxemia may be a cause of postoperative morbidity after routine noncardiac surgery.

A comparison of complete blood replacement with varying hematocrit levels on neurological recovery in a porcine model of profound hypothermic (<5 degrees C) circulatory arrest.

Profound hypothermia (<5 degrees C) may afford better neurological protection after circulatory arrest; however, there are theoretical concerns related to microcirculatory sludging of blood components at these ultra-low temperatures. We hypothesized that at temperatures <5 degrees C, complete blood replacement results in superior neurological outcome. Twelve Yorkshire pigs (30 kg) underwent thoracotomy, cardiopulmonary bypass (CPB), and were randomly assigned to one of three target hematocrits during circulatory arrest: 0%, 5%, 15%. Hextend (6% hetastarch in a balanced electrolyte vehicle) was used for the CPB prime and as an exchange fluid. Animals were cooled to a temperature <5 degrees C, underwent 1-h circulatory arrest, and were warmed to 35 degrees C with administration of blood to increase the hematocrit to >25% before separation from CPB. The primary outcome, peak postoperative neurobehavioral score, was compared between groups. The 0% group (mean +/- SD) had significantly (P: < 0.02) better neurobehavioral scores than the 5% and 15% groups (6.0 +/- 2.9 vs 1.3 +/- 1.0 and 1.5 +/- 0.6) respectively. Other variables (e.g., intracranial pressure) were similar between groups. In a porcine model of profound hypothermia (<5 degrees C) and circulatory arrest, complete blood replacement resulted in superior neurological outcome. This finding suggests that at ultralow temperatures, the presence of some blood component (e.g., erythrocytes, leukocytes) may be deleterious.

Preparation and preclinical evaluation of a novel liposomal complete-core lipopolysaccharide vaccine.

Our objective is to develop a prophylactic vaccine strategy that can be evaluated for surgical and other high-risk hospitalized patients. In this paper, we describe the preparation and preclinical evaluation of a liposomal complete-core lipopolysaccharide (LPS) vaccine that is nontoxic and broadly antigenic. Complete-core (Ra-chemotype) LPSs were isolated from four gram-negative bacterial strains (Escherichia coli K-12, E. coli R1, Pseudomonas aeruginosa PAC608, and Bacteroides fragilis), mixed together to form a cocktail of complete-core LPSs, and then incorporated into multilamellar liposomes consisting of dimyristoyl phosphatidyl choline, dimyristoyl phosphatidylglycerol, and cholesterol in a 4:1:4 molar ratio. The endotoxic activities of these LPS-containing liposomes were less than 0.1% of the endotoxicities of the original free LPSs as measured by the Limulus amoebocyte lysate assay. In vivo administration of liposomal complete-core LPS mixed with Al(OH)(3) to rabbits resulted in no pyrogenicity or overt toxicity over a 7-day period. In immunoblots, sera from rabbits following active immunization elicited cross-reactive antibodies to a large panel of rough and smooth LPSs from numerous clinically relevant gram-negative bacteria, including E. coli (serotypes O1, O4, O6, O8, O12, O15, O18, O75, O86, O157, and O111), P. aeruginosa (Fisher-Devlin serotypes 1, 2, and 3, which correspond to International Antigenic Typing Scheme types 6, 11, and 2, respectively), Klebsiella pneumoniae (serotypes O1, O2ab, and O3), B. fragilis, and Bacteroides vulgatus. Active immunization of mice with liposomal complete-core LPS provided protection against a lethal challenge with E. coli O18 LPS. The vaccine tested was nontoxic, nonpyrogenic, and immunogenic against a wide variety of pathogens found in clinical settings.

Exposure to bacteroides fragilis endotoxin during cardiac surgery.

UNLABELLED: Although endotoxemia has been observed during cardiac surgery, the identity of endotoxins to which patients are exposed is unknown. We tested the hypothesis that antibodies to Bacteroides fragilis (an anaerobic gut commensal and a common pathogen) decrease during cardiac surgery, thereby reflecting systemic exposure to this type of endotoxin. Serum antiendotoxin antibody levels were measured in 55 patients during routine cardiac surgery at the following times: Preoperatively, Pre-CPB (immediately before initiation of cardiopulmonary bypass [CPB]), Pre-CPB+5 (5 min after initiation of CPB), and End (end of surgery). Antiendotoxin antibody levels were determined by using enzyme-linked immunosorbent assay. Total immunoglobulin M (IgM) levels were measured by using laser nephelometry and decreases in total IgM levels were used to control changes in antiendotoxin antibody levels attributable to hemodilution. Median (interquartile range) hemodilution corrected IgM anti-B fragilis antibody levels decreased by 12% (5%-20%) from Preoperatively to End of surgery (P < 0.001). In contrast, median hemodilution corrected anti-B fragilis antibody levels did not change significantly from Pre-CPB to Pre-CPB+5, validating the correction for hemodilution. Immunoglobulin G anti-B fragilis antibody levels and IgM and immunoglobulin G anticore antibody levels decreased similarly during surgery. Intraoperatively, levels of anti-B fragilis endotoxin antibodies decreased significantly out of proportion to hemodilution. These results suggest that cardiac surgical patients are exposed to B fragilis endotoxin. IMPLICATIONS: We prospectively measured hemodilution-corrected antiendotoxin antibody levels in 55 cardiac surgical patients. We observed significant decreases in hemodilution-corrected levels of antibody to both Bacteroides fragilis and the core of endotoxin.

Automated detection of gastric luminal partial pressure of carbon dioxide during cardiovascular surgery using the Tonocap.

BACKGROUND: A new automated system of air tonometry (Tonocap; Datex Ohmeda, Helsinki, Finland) allows for frequent (every 15 min) measurement of gastric luminal partial pressure of carbon dioxide. Its use has not been described in cardiac surgical patients. METHODS: One hundred patients undergoing coronary artery bypass graft or cardiac valve surgery were enrolled in a prospective cohort study. After anesthetic induction and insertion of a TRIP NGS Catheter (Datex Ohmeda), measurements of gastric luminal partial pressure of carbon dioxide were obtained using the Tonocap, and gastric mucosal pH (pHi) was calculated. The main outcome measure was postoperative complication, defined as either in-hospital death or prolonged postoperative hospitalization (> 14 days). RESULTS: Four patients (4%) died, all of multiple-system organ failure, one each on postoperative days 9, 26, 46, and 121. Postoperative complication occurred in 18 patients (18%), all of whom exhibited persistent dysfunction of at least one organ system. Perioperatively, an abnormal pHi (< 7.32) and gastric luminal minus arterial partial pressure of carbon dioxide gap (> 8 mmHg) occurred in 66% and 70% of patients, respectively. Predictors of postoperative complication included postoperative pHi (P = 0.001), gastric luminal partial pressure of carbon dioxide (P = 0.022), and gastric luminal minus arterial partial pressure of carbon dioxide gap (P = 0.013). In contrast, arterial base excess (P > 0.4) and routinely measured hemodynamic variables (e.g., heart rate, blood pressure) were either less predictive compared with Tonocap-derived variables or not predictive. CONCLUSIONS: Despite a low mortality rate, patients undergoing cardiac surgery exhibited high incidences of prolonged hospitalization and postoperative morbidity. The Tonocap was easy to use, particularly compared with saline tonometry. Several Tonocap-derived variables were predictive of postoperative complications consistent with previously published data using saline tonometry.

The use of a postoperative morbidity survey to evaluate patients with prolonged hospitalization after routine, moderate-risk, elective surgery.

UNLABELLED: Vital healthcare resources are devoted to caring for patients with prolonged hospitalization after routine, moderate-risk surgery. Despite the significant cost, little is known about the overall incidence and pattern of complications in these patients. Four hundred thirty-eight patients undergoing a diverse group of routine, moderate-risk, elective surgical procedures were enrolled into a prospective, blinded, cohort study. Complications were assessed using a postoperative morbidity survey. The main outcome was postoperative complication, defined as either in-hospital death or prolonged postoperative hospitalization (> 7 days). The mortality rate was 1.6%. Postoperative complications occurred in 118 patients (27% [95% CI 23-31]). Complications frequently observed in these patients included: gastrointestinal 51% (42-60), pulmonary 25% (17-33), renal 21% (14-28), and infectious 13% (7-19). Most complications were not directly related to the type/site of surgery. Indices of tissue trauma (blood loss [P < 0.001], surgical duration [P = 0.001]) and tissue perfusion (arterial base deficit [P = 0.008], gastric pHi [P = 0.02]) were the strongest intraoperative predictors of complications. Despite a low mortality rate, we found that complications after routine, moderate-risk, elective surgery are common and involve multiple organ systems. Our 9-point survey can be used by healthcare providers and payers to characterize post-operative morbidity in their respective settings. IMPLICATIONS: Little is known about the overall incidence and pattern of complications in patients with prolonged hospitalization after routine, elective surgery. We prospectively assessed these complications using a novel postoperative morbidity survey. The postoperative morbidity survey can be used in future clinical outcome trials, as well as in routine hospital-based quality assurance.