Correlation between shock index and postoperative outcomes for patients undergoing on-pump coronary artery bypass graft surgery (an observational study)

Figures & data

Table 1. Clinical characteristics of the study population. Data are presented as mean (standard deviation) or number (percentage).

	N	Mean	Std. deviation
Age	93	56.67	±11.316
EF % preop	93	53.0108	±16.94
Male	70	75.2%
Female	23	24.7%
DM	42	45.2%
HTN	47	50.5%
Smoking	57	61.3%
Grafts
1 vessel graft	6	6.5%
2 vessel grafts	22	23.6%
3 vessel grafts	41	44%
4 vessel grafts	20	21.5%
5 vessel grafts	4	4.3%
Primary outcomes
Vasopressor	70	75.3%
CV collapse	10	10.8%
AKI	6	6.5%
Ventilation >48 h	8	8.6%
Morbidity	15	16.1%
Mortality	9	9.7%
SI 0	93	.54	±0.11
SI 0	93	.64	±0.16
SI 2	93	.78	±0.26
CC time (minutes)	93	85.15	±30.2
ByP time (minutes)	93	116.86	±54.8
Op. time (minutes)	93	333.23	±105.8

EF = ejection fraction, DM = diabetes mellitus, HTN = hypertension, CV collapse = cardiovascular collapse, AKI = acute kidney injury, SI 0 = shock index pre-induction, SI 1 = shock index after LIMA harvest, SI 2 = shock index after weaning from cardiopulmonary bypass, CC time = cross-clamp time, ByP time = bypass time, Op. time = operation time.

Figure 1. ROC curves for different hemodynamic variables as predictors of cardiovascular collapse.

Table 2. Hemodynamic variables as predictors of cardiovascular collapse.

Variable	AUROC	Sensitivity	Specificity	P value	Cutoff value
Baseline heart rate (HR 0)	0.669	70%	70%	0.09	>84 bpm
Baseline shock index (SI 0)	0.628	90%	31%	0.16	>0.46
Post-LIMA H heart rate (HR 1)	0.678	80%	60%	0.057	>79 bpm
Post-LIMA H shock index (SI 1)	0.618	50%	78%	0.3	>0.7

LIMA H = left internal mammary artery harvest.

Figure 2. Shock index in patients with and without postoperative cardiovascular collapse. Data are presented as columns (mean) and error bars (standard deviation). CV = cardiovascular, *p < 0.05 and **p < 0.01. T 0 pre-induction, T 1 post-LIMA harvest and T 2 after weaning from cardiopulmonary bypass.

Figure 3. Shock index in patients with and without postoperative AKI. Data are presented as columns (mean) and error bars (standard deviation). AKI = acute kidney injury, *p < 0.05 and **p < 0.01.

Table 3. Hemodynamic parameters and their sensitivity and specificity to predict postoperative acute kidney injury.

Variable	AUROC	Sensitivity	Specificity	P value	Cutoff value
Baseline heart rate (HR 0)	0.752	83%	69%	0.01*	>84 bpm
Baseline shock index (SI 0)	0.691	100%	36.78%	0.07	>0.49
Post-LIMAH heart rate (HR 1)	0.759	83.33%	58.62%	0.0041**	>79 bpm
Post-LIMAH shock index (SI 1)	0.784	83.33%	79.31%	0.0296*	>0.7
Post-bypass heart rate (HR 2)	0.919	100%	91.95%	<0.0001**	>105 bpm
Post-bypass shock index (SI 2)	0.929	83.33%	98.85%	<0.0001**	>1.2

LIMA H = left internal mammary artery harvest.

Figure 4. Shock index in patients with and without postoperative prolonged mechanical ventilation >48 h. Data are presented as columns (mean) and error bars (standard deviation). *p < 0.05 and **p < 0.01.

Figure 5. ROC curves for different variables as predictors of prolonged postoperative ventilation >48 h.

Figure 6. Shock index in cases of postoperative in-hospital mortality and in cases where there was no postoperative in-hospital mortality. Data are presented as columns (mean) and error bars (standard deviation). *p < 0.05 and **p < 0.01.

Figure 7. Shock index in patients with and without postoperative morbidity. Data are presented as columns (mean) and error bars (standard deviation). *p < 0.05 and **p < 0.01.