Safe utility of dexmedetomidine target-controlled infusion and ketamine analgosedation in high-risk geriatric patients undergoing prone vertebroplasties—A case series

INTRODUCTION

Vertebroplasty is a minimally invasive procedure typically performed in patients with vertebral fractures. Given the brief duration of the percutaneous procedure involving high-risk geriatric patients with multiple comorbidities, monitored anaesthesia care (MAC) is usually preferred to general anaesthesia (GA). In addition, MAC has fewer side effects than GA in patients undergoing the vertebroplasty procedure.[1] Hence, an optimal sedation regimen is the one that ensures cardiorespiratory stability while providing sufficient analgosedation in the prone position. The use of dexmedetomidine target-controlled infusion (TCI) has gained importance for procedures under sedation in the operating room (OR).[2]

CASE REPORT

We report four high-risk geriatric patients with pathological vertebral fractures who underwent prone vertebroplasties using dexmedetomidine TCI and ketamine analgosedation regimen. All patients have provided written consent for the publication of this report.

The patients were categorised as American Society of Anesthesiologists (ASA) physical status class 3. The perioperative patient details are provided in Table 1. Every subject had a baseline visual analogue scale (VAS) for pain score more than 5. Electrocardiogram, peripheral oxygen saturation (SpO₂), and non-invasive blood pressure monitors were attached, and baseline parameters were recorded in the OR. To minimise the pain before proning, intravenous (IV) fentanyl (1 μg/kg) and ketamine (0.25 mg/kg) boluses were administered along with IV glycopyrrolate (0.2 mg). Dexmedetomidine TCI and a separate IV ketamine manual infusion (0.5 mg/kg/h) were started in the prone position. The dexmedetomidine TCI using the Dyck pharmacokinetic model (Arcomed pump, Zurich, Switzerland) was titrated (Cp = 0.5 to 1.2 ng/ml) to an Observer’s Assessment of Alertness/Sedation (OAA/S) scale of 3. All patients received high-flow nasal oxygen (HFNO) at a flow rate of 20–30 L/min to prevent intraoperative desaturation [Figure 1]. The vertebroplasties were performed after skin infiltration with 8–10 ml of 2% plain lignocaine, and none of the patients moved throughout the procedure. All patients were haemodynamically stable with SpO₂ >95%, and none of the patients had an adverse respiratory event. Both sedations were discontinued 10 minutes before completion of the procedure, and the patients were turned supine. All patients had an OAA/S scale of 4 to 5 and a VAS of 2 to 3 in the immediate postoperative period without any delirium. The patients were shifted out of the post-anaesthetic care unit within 1 hour. There were no significant changes in renal and liver function parameters postoperatively.

Table 1.

Patient demographics and medical comorbidities

Case Details	Case 1	Case 2	Case 3	Case 4
Age (years) and gender	73/male	69/female	67/female	75/female
Weight (kg)	55	52	58	54
Diagnosis	D12 osteoporotic fracture	L1, D10, D12 osteoporotic fracture	D11 osteoporotic fracture	L2, L3, D6 osteoporotic fracture
Comorbidities	Carcinoma prostate, Parkinson’s disease, COPD, hypertension ECHO – EF 55% Grade 1 LVDD	Diabetes, CLD (INR-1.7) with portal hypertension, ascites ECHO– EF 60% Grade 1 LVDD	CKD on dialysis (elevated creatinine), diabetes, hypertension, post-CABG surgery, ECHO-EF 50%, dilated left atrium) Grade 1 LVDD	Bronchial asthma, hypertension, CKD on dialysis (elevated creatinine), history of pneumonia (CXR—mild pulmonary edema) ECHO – EF 60% Grade 1 LVDD
ASA class	3	3	3	3
Baseline vitals
HR (bpm)	80	80	76	90
BP (mmHg)	170/90	125/80	145/98	160/90
SpO2 (%)	97	98	98	95%
Intraoperative vitals
HR (bpm)	80-90	85-111	78-89	78-100
BP (mmHg)	140-160/80-90	111-143/70-90	105-145/52-98	105-165/60-90
Lowest SpO2 (%)	100%	99%	98%	100%

ASA=American Society of Anesthesiologists, COPD=Chronic obstructive pulmonary disease, CKD=Chronic kidney disease, CLD=Chronic liver disease, CXR=Chest X-ray, ECHO=Electrocardiogram, HR=Heart rate, BP=Blood pressure, SpO₂=Oxygen saturation, EF=Ejection fraction, LVDD=Left ventricular diastolic dysfunction, INR=International normalised ratio, bpm=Beats per minute, CABG=Coronary artery bypass grafting

Figure 1.

Geriatric patient undergoing prone vertebroplasty with dexmedetomidine target-controlled infusion and ketamine analgosedation with high-flow nasal oxygenation

DISCUSSION

Dexmedetomidine and ketamine analgosedation provide numerous benefits for high-risk geriatric patients. Firstly, both dexmedetomidine and ketamine exert minimal effects on respiration and upper airway tone, thereby decreasing the likelihood of adverse airway events in the prone position. Secondly, the combination offers significant analgesic effects, thereby limiting patient movement and enhancing the surgical process. Thirdly, the opposing haemodynamic effects of dexmedetomidine (a sympatholytic agent) and ketamine (a sympathetic stimulant) contribute to haemodynamic stability in the prone position. The dexmedetomidine TCI and ketamine protocol combined with HFNO ensured cardiorespiratory stability in our patients. Also, no postoperative delirium was observed with ketamine that could be attributed to the counteractive effects of dexmedetomidine. Dexmedetomidine TCI using the Dyck model was chosen due to its precision and predictability, with a concentration range of 0 to 2 ng/ml yielding effective sedation.[3] Dexmedetomidine demonstrates a favourable safety profile in patients with renal and hepatic impairments.[4,5] Renal dysfunction may impede ketamine clearance; however, there is no evidence contraindicating the use of short duration subanaesthetic doses of ketamine infusions in patients with renal failure.[6] Modest increases in liver enzymes may occur with subanaesthetic doses of ketamine; however, this does not result in clinical liver impairment.[6]

CONCLUSION

The counteractive effects of dexmedetomidine and ketamine are beneficial when combined. The dexmedetomidine TCI and ketamine analgosedation regimen can be a safer option to ensure cardiorespiratory stability and facilitate the prone vertebroplasties in high-risk elderly patients.

Presentation at conferences/CMEs and abstract publication

Nil.

Study data availability

De-identified data may be requested with reasonable justification from the authors (email to the corresponding author) and shall be shared after approval as per the authors’ institution’s policy.

Disclosure of use of artificial intelligence (AI)-assistive or generative tools

The AI tools or language models (LLM) have not been utilised in the manuscript, except that software has been used for grammar corrections and references.

Declaration of use of permitted tools

The figures and tables are self-prepared and not copyrighted.

Author contributions

BV: Concepts, design, definition of intellectual content, literature search, conduct of cases, data acquisition, data analyses, and manuscript preparation. SA: Conduct of cases, manuscript preparation, editing, review and approval, supervision. DM: Conduct of cases, manuscript editing, review and approval, supervision. RG, SR: Manuscript editing, review and approval, supervision.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

None.