Hemodynamic monitoring of the postoperative adult cardiac surgical patient

Incidence of Myocardial Infarction After High-Risk Vascular Operations in Adults

Importance

Advances in perioperative cardiac management and an increase in the number of endovascular procedures have made significant contributions to patients and postoperative myocardial infarction (POMI) risk following high-risk vascular procedures. Whether these changes have translated into real-world improvements in POMI incidence remain unknown.

Objective

To examine the temporal trends of myocardial infarction (MI) following high-risk vascular procedures.

Design, Setting, and Participants

A retrospective cohort study was performed using data collected from January 1, 2005, to December 31, 2013, in the American College of Surgeons National Surgery Quality Improvement Program database, to which participating hospitals across the United States report their preoperative, operative, and 30-day outcome data. A total of 90 303 adults who underwent a high-risk vascular procedure-open aortic surgery or infrainguinal bypass-during the study period were identified. Patients were divided into cohorts based on their year of operation, and their baseline cardiac risk factors and incidence of POMI were compared. Cases from 2005 to 2014 in the database were eligible for inclusion if one of their Current Procedural Terminology codes matched any of the operations identified as a high-risk vascular procedure. Data analysis took place from August 1, 2016, to November 15, 2016.

Exposures

The main exposure was the year of the operation. Other variables of interest included demographics, comorbidities, and other risk factors for MI.

Main Outcomes and Measures

Primary outcome of interest was the incidence of POMI.

Results

Of the 90 303 patients included in the study, 22 836 (25.3%) had undergone open aortic surgery and 67 467 (74.7%) had had infrainguinal bypass. The open aortic cohort comprised 16 391 men (71.9%), had a mean (SD) age of 69.1 (11.5) years, and was predominantly white (18 440 patients [80.8%] self-identified as white race/ethnicity). The infrainguinal bypass cohort included 41 845 men (62.1%), had a mean (SD) age of 66.7 (11.7) years, and had 51 043 patients (75.7%) who self-identified as white race/ethnicity. During the study period, patients who underwent open aortic procedures were more likely to be classified as American Society of Anesthesiologists class IV (7426 patients [32.6%] vs 15 683 [23.3%] for the infrainguinal bypass cohort) or class V (1131 [5.0%] vs 206 [0.3%]; P < .001) and to undergo emergency procedures (4852 [21.3%] vs 4954 [7.3%]; P < .001). The open aortic procedure cohort also experienced significantly higher actual incidence of POMI (464 [3.0%] vs 1270 [1.9%]; P < .001). From 2009 to 2014, the incidence of POMI demonstrated no substantial temporal change (2.7% in 2009 to 3.1% in 2014; P = .64 for trend). Postoperative MI was consistently associated with poor prognosis, with a 3.62-fold (95% CI, 2.25-5.82) to 11.77-fold (95% CI, 6.10-22.72) increased odds of cardiac arrest and a 3.01-fold (95% CI, 2.08-4.36) to 6.66-fold (95% CI, 4.66-9.52) increased odds of mortality.

Conclusions and Relevance

The incidence of MI did not significantly decrease in the past decade and has been consistently associated with worse clinical outcomes. Further inquiry into why advanced perioperative care did not reduce cardiac complications is important to quality improvement efforts.

Comparison of pre- and postoperative pulmonary function in obese and non-obese female patients undergoing coronary artery bypass graft surgery

OBJECTIVE AND BACKGROUND

Various studies have suggested that body size and in-hospital mortality are related. However, only a few analysed the effects of obesity on pulmonary complications following coronary artery bypass graft surgery (CABG). The purpose of the present study was to assess early changes in lung volumes, respiratory complications and arterial blood gas tension following CABG in obese women.

METHODS

Pulmonary function tests (PFTs), treadmill exercise capacity tests (TM), arterial blood gases and pulmonary complications were studied in 124 obese (mean age 57.2+/-5.8 years) and 108 non-obese (mean age 58.6+/-5.9 years) female patients undergoing elective CABG. PFT, TM tests, arterial blood gas analyses and CXR were performed in the preoperative and postoperative periods and pulmonary complications were recorded. Breathing and coughing exercises, early ambulation and pulmonary clearing techniques were used by physical therapists to prevent pulmonary complications after CABG surgery.

RESULTS

Postoperative PFT and TM tests deteriorated significantly in both groups (P<0.0001). The deterioration in the obese group was highly significant. The postoperative deterioration of blood gas measurements in obese patients was also statistically significant compared to non-obese patients. Early pulmonary complications developed in 21 (16.94%) of the obese patients and in 10 (9.25%) of non-obese patients. Duration of mechanical ventilation, intensive care unit and hospital stays were longer compared to the non-obese patients (P=0.008, P<0.0001, P=0.0386, respectively).

CONCLUSION

Obesity has a detrimental effect on pulmonary function, exercise capacity, blood gas measurements and complications rates in postoperative period following CABG surgery.

Effects of smoking on pulmonary functions and arterial blood gases following coronary artery surgery in Turkish patients

The effects of smoking on postoperative lung volumes, arterial blood gas tensions, and pulmonary complications were studied prospectively in 213 consecutive Turkish patients undergoing elective coronary artery bypass graft surgery. One hundred and seventeen patients were current smokers (19 females, 98 males, mean age. 59.0 +/- 6.1 years. group 1) and 96 were nonsmokers (40 females, 56 males mean age. 59.6 +/- 5.8 years, group 2). Demographic data and the anesthesia and surgical methods were similar in both groups. Pulmonary function tests, arterial blood gas analyses, and chest radiographs were done preoperatively and postoperatively. Pulmonary complications were recorded. Postoperative partial arterial oxygen tension values in both groups revealed moderate hypoxemia which was more intense in smokers (decreased from preop. 82.0 +/- 7.8 mmHg to postop. 66.1 +/- 8.0 mmHg). Mean partial carbon dioxide tension increased significantly, remaining within acceptable limits (from 32.5 +/- 2.2 mmHg to 38.6 +/- 3.6 mmHg) in smokers following surgery. The postoperative pulmonary function test values decreased significantly in both groups but the deterioration in the smoking group was highly significant, except for FMFT. In the smokers, the preoperative mVC/pFVC (%) value was at the lower normal limit which indicates slight restrictive respiratory problems. Patients in both groups developed a severe restrictive ventilatory defect after coronary artery surgery (P < 0.0001 for both), but this restriction was also statistically significant in the smoking group compared to nonsmokers after surgery (mVC/pFVC from 74.7 +/- 12.6% to 52.3 +/- 10.0% and 80.8 +/- 13.5% to 63.2 +/- 10.7%. in the smokers and nonsmokers, respectively). Also, the significantly greater decrease in the FEV1/FVC ratio in the smokers (from 75.4 +/- 12.2% to 72.2 +/- 11.5%) (P = 0.037) was indicative of greater airway obstruction. Pulmonary complications developed in 20.5% (24 people) of the smokers and 10.4% (10 people) of the nonsmokers. The mean time to extubation, intensive care unit stay, and hospital stay for groups 1/2 were 19.9 +/- 11.5/14.1 +/- 4.3 hours (P < 0.0001) 3.2 +/- 1.3/2.4 +/- 0.6 days (P < 0.0001), and 14.1 +/- 4.4/12.5 +/- 2.4 days (P = 0.0013), respectively. For the male group, we obtained results similar to those for the whole (males + females) study population and concluded that the observed differences in various parameters between smokers and nonsmokers were not due to gender. As a result. we revealed that cigarette smoking affects pulmonary functions by causing obstructive type respiratory problems and by worsening existing restrictive type respiratory problems postoperatively. The postoperative deterioration in blood gas measurements of smokers was also statistically significant compared with nonsmokers. In addition, the incidence of pulmonary complications in smokers was 2-fold greater than in nonsmokers and was related to the number of cigarettes consumed daily, leading to prolongation of the postoperative intubation period, and ICU and hospital stays.