Adverse Effects Associated with Patient-Controlled Analgesia with Ketamine Combined with Opioids and Ketamine Infusion with PCA Bolus in Postoperative Spine Patients: A Retrospective Review

Figures & data

Table 1 Patient Characteristics in the Ketamine Infusion with PCA Bolus Group, Combined Hydromorphone and Ketamine PCA Group, and Combined Morphine and Ketamine PCA Group (N=315)

Characteristics	Ketamine Infusion with PCA Bolus (n=68)	Hydromorphone/Ketamine PCA (n=203)	Morphine/Ketamine PCA (n=44)	P value
Age	58 [12]	55 [13]	52 [12]	0.04*
Gender (Male)	29 (42%)	92 (45%)	18 (41%)	0.8
Gender (Female)	39 (57%)	111 (55%)	26 (59%)
BMI	28 [6]	28 [6]	29 [7]	0.5
ASA status				0.4
1	1 (2%)	1 (1%)	0 (0%)
2	28 (41%)	98 (48%)	17 (39%)
3	39 (57%)	100 (49%)	26 (59%)
4	0 (0%)	4 (2%)	1 (2%)
Chronic pain diagnosis	60 (88%)	187 (92%)	43 (98%)	0.2
Preoperative MEDD	61 [68]	102 [122]	113 [114]	0.02*
Prior Spine surgery	53 (78%)	154 (76%)	32 (73%)	0.8

Note: *Statistical significance with p<0.05.

Table 2 Intraoperative Variables in the Ketamine Infusion with PCA Bolus Group, Combined Hydromorphone and Ketamine PCA Group, and Combined Morphine and Ketamine PCA Group (N=315)

Intraoperative Variables	Ketamine Infusion with PCA Bolus (n=68)	Hydromorphone/Ketamine PCA (n=203)	Morphine/Ketamine PCA (n=44)	P value
Multi-level spine surgery	44 (65%)	152 (75%)	32 (73%)	0.3
Received intraoperative ketamine	56 (82%)	91 (45%)	27 (61%)	<0.01*
Dose of Intraoperative ketamine (in mg)	75 [42]	75 [58]	84 [26]	0.7
Intraoperative MEDD	63 [39]	79 [52]	81 [46]	0.05

Note: *Statistical significance with p<0.05.

Table 3 Incidence of ADEs and Other Variables in the Ketamine Infusion with PCA Bolus Group, Combined Hydromorphone and Ketamine PCA Group, and Combined Morphine and Ketamine PCA Group (N=315)

Variable	Ketamine Infusion with PCA Bolus (n=68)	Hydromorphone/Ketamine PCA (n=203)	Morphine/Ketamine PCA (n=44)	Total (n=315)	P value	Q value
Any ADE	16 (24%)	77 (38%)	28 (64%)	121 (38%)	<0.01*	<0.01*
Psychological symptoms	2 (3%)	11 (5%)	9 (21%)	22 (7%)	<0.01*	0.02*
Neurological symptoms	1 (2%)	6 (3%)	3 (7%)	10 (3%)	0.3	>0.9
Nausea with or without emesis	1 (2%)	22 (11%)	17 (39%)	40 (13%)	<0.01*	<0.01*
New-onset tachycardia	10 (15%)	46 (23%)	12 (27%)	68 (22%)	0.2	>0.9
PCA abruptly stopped	5 (7%)	9 (4%)	5 (11%)	19 (6%)	0.2	>0.9
Rapid response	0 (0%)	2 (1%)	0 (0%)	2 (1%)	>0.9	>0.9
PCA duration (days)	3 (2)	2 (2)	2 (1)	2 (2)	0.2	>0.9
Hospital stay (days)	5 (3)	6 (5)	6 (7)	6 (5)	>0.9	>0.9
Postoperative MEDD	286 (223)	847 (1257)	353 (350)	657 (1054)	<0.01*	<0.01*

Note: *Statistical significance with p<0.05.

Table 4 Comparison of Incidence of Ketamine ADEs Among Retrospective and Meta-Analysis of Prospective Studies

Study	Any ADE	Psychological Symptoms	Neurological Symptoms	Nausea	New-Onset Tachycardia
Pouldar et al	38% (22%)*	7%	3%	13%	22%
Stoker et al	29.5%	14.8%	5.3%^†	n/a	n/a
Schwenk et al	31.8%	16.2%	9.4%^†	2.8%	2.8%^‡
Laskowski et al	n/a	7.4%	2.5%^†	25.6%	n/a
Elia, Tramer	n/a	7.4%	4%^†	22%	n/a

Notes: *Any ADE when New-onset tachycardia is not included. ^†Defined neurological symptoms as sedation or drowsiness in Stoker, Schwenk, Laskowski, and Elia studies. ^‡Defined hemodynamic instability as tachycardia, hypertension, and hypotension.