Hemodynamic changes in the prone position according to fluid loading after anaesthesia induction in patients undergoing lumbar spine surgery: a randomized, assessor-blind, prospective study

Figures & data

Figure 1. Patient flow chart.

Table 1. Demographic data of the study cohort.

	Group M (n = 40)	Group L (n = 40)	p Value
Age (years)	69 (64–75)	71 (66–75)	0.232
Sex (male/female) (n)	13/27	12/28	1.000
BMI (kg/m^2)	24.9 (22.4–26.9)	24.9 (22.3–28.1)	0.697
ASA-PS class (I/II/III)	3/33/4	3/31/6	0.794
Diabetes mellitus (n)	12	12	1.000
Smoking (non/ex/current) (n)	32/2/6	36/2/2	0.327
White blood cell (×10^3/µl)	7.08 (5.45–9.29)	6.93 (5.69–8.58)	0.939
Hematocrit (%)	38.8 (35.6–42.2)	38.9 (34.9–40.8)	0.795
Platelet (×10^3/µl)	216 (182–248)	244 (204–266)	0.125
INR	0.98 (0.95–1.03)	0.98 (0.96–1.02)	0.725
AST (U/L)	25 (21–30)	23 (20–28)	0.149
ALT (U/L)	21 (17–29)	20 (16–25)	0.296
Creatinine (mg/dL)	0.69 (0.58–0.84)	0.68 (0.51–0.81)	0.482
Number of operated levels (n)			0.902
1	14	13
2	9	8
≥3	17	19

Data are presented as medians (interquartile ranges) or numbers.

M: maintenance; L: loading; BMI: body mass index; ASA-PS: American Society of Anesthesiologists physical status; INR: international normalized ratio; AST: aspartate transaminase; ALT: alanine transaminase.

Figure 2. Forest plot of the odds ratios for hypotension before surgical incision.

BP: blood pressure; PVi: pleth variability index.

Figure 3. Receiver operating characteristic curve analysis of pleth variability index according to hypotension before surgical incision.

PVi: pleth variability index; AUC: area under curve; Sens: sensitivity; Spec: specificity; PPV: positive predictive value; NPV: negative predictive value.

Table 2. Perioperative data of the study cohort.

	Group M (n = 40)	Group L (n = 40)	p Value
During anaesthesia induction
Dose of phenylephrine (µg)	50 (0–150)	0 (0–50)	0.005*
Ephedrine administration (n)	2 (5%)	1 (2.5%)	1.000
Incidence of hypotension (n)	25 (62.5%)	13 (32.5%)	0.014*
Intraoperative data
Fluid administration (ml)	2100 (950–4450)	1650 (1150–3100)	0.510
Packed RBC transfusion (unit)	2 (0–4)	1 (0–3)	0.516
Estimated blood loss (ml)	900 (500–2000)	800 (400–1400)	0.380
Urine output (ml)	650 (200–1050)	490 (250–800)	0.497
Operation time (min)	187 (132–307)	168 (115–270)	0.366
Postoperative data
Discharge to ICU (n)	13 (32.5%)	13 (32.5%)	1.000
Hospital length of stay (days)	22 (14–50)	26 (13–48)	0.802

Data are presented as medians (interquartile ranges) or numbers (%).

M: maintenance; L: loading; RBC: red blood cell; ICU: intensive care unit.

*Statistically significant.

Table 3. Univariable and multivariable logistic regression analysis of factors associated with hypotension before surgical incision.

	Univariable		Multivariable
	OR (95% CI)	p Value	OR (95% CI)	p Value
Age	1.00 (0.94–1.05)	0.897
Female	1.98 (0.76–5.41)	0.168	2.27 (0.71–7.74)	0.173
Body mass index	1.07 (0.94–1.21)	0.315	1.07 (0.92–1.25)	0.406
Diabetes mellitus	0.91 (0.34–2.37)	0.845
Baseline mean BP	1.02 (0.99–1.06)	0.174	1.03 (0.99–1.07)	0.235
Baseline heart rate	1.03 (1.00–1.07)	0.091	1.03 (0.99–1.07)	0.125
Baseline PVi	1.13 (1.02–1.27)	0.022*	1.19 (1.06–1.36)	0.007*
Postinduction SVV	1.00 (0.89–1.12)	0.998
Postinduction PPV	1.04 (0.95–1.14)	0.435
Loading group	0.29 (0.11–0.71)	0.008*	0.22 (0.07–0.61)	0.005*

OR: odds ratio; CI: confidence interval; BP: blood pressure; PVi: pleth variability index; SVV: stroke volume variation; PPV: pulse pressure variation.

*Statistically significant.

Figure 4. Mean blood pressure and heart rate before surgical incision.

M: maintenance; L: loading; ANS: anaesthesia. *Significant differences.

Figure 5. Pleth variability index, stroke volume variation and pulse pressure variation before surgical incision.

M: maintenance; L: loading; ANS: anaesthesia. *Significant differences.

Figure 6. Postoperative complications.

M: maintenance; L: loading; PPC: postoperative pulmonary complications; PONV: postoperative nausea and vomiting; AKI: acute kidney injury.

Data availability statement

The datasets used and analysed in the current study are available from the corresponding author upon reasonable request. The data are not publicly available because of privacy and ethical restrictions.