Low Tidal Volumes Are Associated With Slightly Improved Oxygenation in Patients Having Cardiac Surgery: A Cohort Analysis.

BACKGROUND: Mechanical ventilation with low tidal volumes appears to provide benefit in patients having noncardiac surgery; however, whether it is beneficial in patients having cardiac surgery is unclear. METHODS: We retrospectively examined patients having elective cardiac surgery requiring cardiopulmonary bypass through a median sternotomy approach who received mechanical ventilation with a single lumen endotracheal tube from January 2010 to mid-August 2016. Time-weighted average tidal volume (milliliter per kilogram predicted body weight [PBW]) during the duration of surgery excluding cardiopulmonary bypass was analyzed. The association between tidal volumes and postoperative oxygenation (measured by arterial partial pressure of oxygen (PaO2)/fraction of inspired oxygen ratio [PaO2/FIO2]), impaired oxygenation (PaO2/FIO2 <300), and clinical outcomes were examined. RESULTS: Of 9359 cardiac surgical patients, larger tidal volumes were associated with slightly worse postoperative oxygenation. Postoperative PaO2/FIO2 decreased an estimated 1.05% per 1 mL/kg PBW increase in tidal volume (97.5% confidence interval [CI], -1.74 to -0.37; PBon = .0005). An increase in intraoperative tidal volumes was also associated with increased odds of impaired oxygenation (odds ratio [OR; 97.5% CI]: 1.08 [1.02-1.14] per 1 mL/kg PBW increase in tidal volume; PBon = .0029), slightly longer intubation time (5% per 1 mL/kg increase in tidal volume (hazard ratio [98.33% CI], 0.95 [0.93-0.98] per 1 mL/kg PBW; PBon < .0001), and increased mortality (OR [98.33% CI], 1.34 [1.06-1.70] per 1 mL/kg PBW increase in tidal volume; PHolm = .0144). An increase in intraoperative tidal volumes was also associated with acute postoperative respiratory failure (OR [98.33% CI], 1.16 [1.03-1.32] per 1 mL/kg PBW increase in tidal volume; PHolm = .0146), but not other pulmonary complications. CONCLUSIONS: Lower time-weighted average intraoperative tidal volumes were associated with a very modest improvement in postoperative oxygenation in patients having cardiac surgery.

Systemic Lupus Erythematosus Is Associated With Increased Adverse Postoperative Renal Outcomes and Mortality: A Historical Cohort Study Using Administrative Health Data.

BACKGROUND: Systemic lupus erythematosus (SLE) is a common autoimmune connective tissue disease that mainly harms kidneys, heart, lungs, and nervous system. Effects of surgical stimulus and anesthesia combined with SLE-related pathologies may increase morbidity and mortality. Therefore, we aimed to evaluate the association between SLE (versus none) and postoperative renal, cardiac, and in-hospital mortality complications among patients undergoing major surgeries. METHODS: We obtained censuses of 2009 to 2011 inpatient hospital discharges across 7 states and conducted a retrospective cohort study by using International Classification of Diseases and Injuries, Version 9, diagnosis codes, procedure codes, and present-on-admission indicators. We included patients who had major surgery and matched each SLE discharge up to 4 control discharges for potential confounders. We assessed the association between matched SLE patients and controls on in-hospital renal complications, cardiovascular complications, and in-hospital mortality using separate logistic regression models. RESULTS: Among 8 million qualifying discharges, our sample contained 28,269 SLE patients matched with 13,269 controls. SLE was associated with a significantly higher risk of postoperative renal complications, with an estimated odds ratio (99% CI) of 1.33 (1.21, 1.46); P < .001. In addition, SLE was significantly associated with a higher risk of in-hospital mortality, with an estimated odds ratio (99% CI) of 1.27 (1.11, 1.47); P < .001. However, we found no significant association between SLE and cardiac complications, with an estimated odds ratio (99% CI) of 0.98 (0.83, 1.16), P = .79. CONCLUSIONS: This is, by far, the largest clinical study for postoperative outcomes of SLE patients with adequately powered statistical analyses. We concluded that SLE was associated with a higher risk of renal complications and in-hospital mortality but not cardiac events after major surgery. In SLE patients, more aggressive measures should be taken to prevent renal injury in the perioperative period.

Renal injury after open versus laparoscopic non-cardiac surgery: a retrospective cohort analysis.

BACKGROUND: Laparoscopic surgical approaches enhance recovery, reduce postoperative pain, and shorten hospital length-of-stay. Nevertheless, increased intra-abdominal pressure is associated with decreased renal blood flow, renal hypoxia and acute kidney injury. When combined with Trendelenburg positioning, renal function may further deteriorate. We tested the primary hypothesis that the combination of laparoscopic surgical approach and Trendelenburg position is associated with larger reductions in estimated Glomerular Filtration Rate (eGFR) within the initial 48 postoperative hours compared to open surgery without Trendelenburg positioning. Secondarily, we tested, if laparoscopic procedures are associated with greater incidence of postoperative acute kidney injury. METHODS: Adults who had laparoscopic colorectal surgery in Trendelenburg position at the Cleveland Clinic Main Campus from 2009 to 2016 were propensity-matched to patients who had comparable open procedures. Patients with pre-existing renal impairment were excluded. RESULTS: Among 7,357 eligible patients, 1,846 laparoscopic cases with Trendelenburg were matched to 1,846 open cases. No association was found between laparoscopic approach and postoperative eGFR. A significant protective effect of the laparoscopic procedure on the odds of having AKI was found. Patients who had laparoscopic surgeries were an estimated 0.70 (95% CI 0.55, 0.90, pHolm-adj = 0.006) times as likely to have AKI as open surgical patients. CONCLUSION: Despite compelling potential mechanisms, laparoscopic approach with Trendelenburg position in adult colorectal surgeries did not worsen postoperative eGFR, and actually reduced postoperative acute kidney injury. Given the other advantages of laparoscopic surgery, the approach should not be avoided for concerns about renal injury.