Comparing preoperative fasting and ultrasound-measured intravascular volume status in elective surgery, enhanced recovery patients versus inpatient, urgent surgery patients and the ability of IVC collapsibility to predict post-induction hypotension.

Hypotension following induction of general anaesthesia has been shown to result in increased complications and mortality postoperatively. Patients admitted to the hospital undergoing urgent surgery are often fasted from fluids for significant periods compared to elective patients subject to Enhanced Recovery After Surgery protocols despite guidelines stating that a two-hour fast is sufficient. The aim of this prospective, observational study was to compare fasting times and intravascular volume status between elective surgery patients subject to enhanced recovery protocols and inpatient, urgent surgery patients and to assess differences in the incidence of post-induction hypotension. Fasting data was obtained by questionnaire in the preoperative area in addition to inferior vena cava collapsibility index, a non-invasive measure of intravascular volume. Blood pressure readings and drug administration for the ten minutes following induction were obtained from patients' charts. Inpatients undergoing urgent surgery were fasted significantly longer than enhanced recovery patients and had lower intravascular volume. However, no difference was found in the incidence of post-induction hypotension.

Bleeding After Musculoskeletal Surgery in Hospitals That Switched From Hydroxyethyl Starch to Albumin Following a Food and Drug Administration Warning.

BACKGROUND: While US Food and Drug Administration (FDA) black box warnings are common, their impact on perioperative outcomes is unclear. Hydroxyethyl starch (HES) is associated with increased bleeding and kidney injury in patients with sepsis, leading to an FDA black box warning in 2013. Among patients undergoing musculoskeletal surgery in a subset of hospitals where colloid use changed from HES to albumin following the FDA warning, we examined the rate of major perioperative bleeding post- versus pre-FDA warning. METHODS: The authors of this article used a retrospective, quasi-experimental, repeated cross-sectional, interrupted time series study of patients undergoing musculoskeletal surgery in hospitals within the Premier Healthcare Database, in the year before and year after the 2013 FDA black box warning. We examined patients in 23 "switcher" hospitals (where the percentage of colloid recipients receiving HES exceeded 50% before the FDA warning and decreased by at least 25% in absolute terms after the FDA warning) and patients in 279 "nonswitcher" hospitals. Among patients having surgery in "switcher" and "nonswitcher" hospitals, we determined monthly rates of major perioperative bleeding during the 12 months after the FDA warning, compared to 12 months before the FDA warning. Among patients who received surgery in "switcher" hospitals, we conducted a propensity-weighted segmented regression analysis assessing differences-in-differences (DID), using patients in "nonswitcher" hospitals as a control group. RESULTS: Among 3078 patients treated at "switcher" hospitals (1892 patients treated pre-FDA warning versus 1186 patients treated post-FDA warning), demographic and clinical characteristics were well-balanced. Two hundred fifty-one (13.3%) received albumin pre-FDA warning, and 900 (75.9%) received albumin post-FDA warning. Among patients undergoing surgery in "switcher" hospitals during the pre-FDA warning period, 282 of 1892 (14.9%) experienced major bleeding during the hospitalization, compared to 149 of 1186 (12.6%) following the warning. In segmented regression, the adjusted ratio of slopes for major perioperative bleeding post- versus pre-FDA warning was 0.98 (95% confidence interval [CI], 0.93-1.04). In the DID estimate using "nonswitcher" hospitals as a control group, the ratio of ratios was 0.93 (95% CI, 0.46-1.86), indicating no significant difference. CONCLUSIONS: We identified a subset of hospitals where colloid use for musculoskeletal surgery changed following a 2013 FDA black box warning regarding HES use in sepsis. Among patients undergoing musculoskeletal surgery at these "switcher" hospitals, there was no significant decrease in the rate of major perioperative bleeding following the warning, possibly due to incomplete practice change. Evaluation of the impact of systemic changes in health care may contribute to the understanding of patient outcomes in perioperative medicine.

Intraoperative protective mechanical ventilation and risk of postoperative respiratory complications: hospital based registry study.

OBJECTIVE: To evaluate the effects of intraoperative protective ventilation on major postoperative respiratory complications and to define safe intraoperative mechanical ventilator settings that do not translate into an increased risk of postoperative respiratory complications. DESIGN: Hospital based registry study. SETTING: Academic tertiary care hospital and two affiliated community hospitals in Massachusetts, United States. PARTICIPANTS: 69,265 consecutively enrolled patients over the age of 18 who underwent a non-cardiac surgical procedure between January 2007 and August 2014 and required general anesthesia with endotracheal intubation. INTERVENTIONS: Protective ventilation, defined as a median positive end expiratory pressure (PEEP) of 5 cmH2O or more, a median tidal volume of less than 10 mL/kg of predicted body weight, and a median plateau pressure of less than 30 cmH2O. MAIN OUTCOME MEASURE: Composite outcome of major respiratory complications, including pulmonary edema, respiratory failure, pneumonia, and re-intubation. RESULTS: Of the 69,265 enrolled patients 34,800 (50.2%) received protective ventilation and 34,465 (49.8%) received non-protective ventilation intraoperatively. Protective ventilation was associated with a decreased risk of postoperative respiratory complications in multivariable regression (adjusted odds ratio 0.90, 95% confidence interval 0.82 to 0.98, P=0.013). The results were similar in the propensity score matched cohort (odds ratio 0.89, 95% confidence interval 0.83 to 0.97, P=0.004). A PEEP of 5 cmH2O and median plateau pressures of 16 cmH2O or less were associated with the lowest risk of postoperative respiratory complications. CONCLUSIONS: Intraoperative protective ventilation was associated with a decreased risk of postoperative respiratory complications. A PEEP of 5 cmH2O and a plateau pressure of 16 cmH2O or less were identified as protective mechanical ventilator settings. These findings suggest that protective thresholds differ for intraoperative ventilation in patients with normal lungs compared with those used for patients with acute lung injury.

Dose-dependent Association between Intermediate-acting Neuromuscular-blocking Agents and Postoperative Respiratory Complications.

BACKGROUND: Duration of action increases with repeated administration of neuromuscular-blocking agents, and intraoperative use of high doses of neuromuscular-blocking agent may affect respiratory safety. METHODS: In a hospital-based registry study on 48,499 patients who received intermediate-acting neuromuscular-blocking agents, the authors tested the primary hypothesis that neuromuscular-blocking agents are dose dependently associated with the risk of postoperative respiratory complications. In the secondary analysis, the authors evaluated the association between neostigmine dose given for reversal of neuromuscular-blocking agents and respiratory complications. Post hoc, the authors evaluated the effects of appropriate neostigmine reversal (neostigmine ≤ 60 µg/kg after recovery of train-of-four count of 2) on respiratory complications. The authors controlled for patient-, anesthesia-, and surgical complexity-related risk factors. RESULTS: High doses of neuromuscular-blocking agents were associated with an increased risk of postoperative respiratory complications (n = 644) compared with low doses (n = 205) (odds ratio [OR], 1.28; 95% CI, 1.04 to 1.57). Neostigmine was associated with a dose-dependent increase in the risk of postoperative respiratory complications (OR, 1.51; 95% CI, 1.25 to 1.83). Post hoc analysis revealed that appropriate neostigmine reversal eliminated the dose-dependent association between neuromuscular-blocking agents and respiratory complications (for neuromuscular-blocking agent effects with appropriate reversal: OR, 0.98; 95% CI, 0.63 to 1.52). CONCLUSIONS: The use of neuromuscular-blocking agents was dose dependently associated with increased risk of postoperative respiratory complications. Neostigmine reversal was also associated with a dose-dependent increase in the risk of respiratory complications. However, the exploratory data analysis suggests that the proper use of neostigmine guided by neuromuscular transmission monitoring results can help eliminate postoperative respiratory complications associated with the use of neuromuscular-blocking agents.