Fractional spinal anaesthesia in high-risk elderly patients for orthopaedic surgery – Case series

ABSTRACT

Elderly patients coming for orthopaedic surgeries usually have many comorbidities. This makes them potentially vulnerable to haemodynamic instability with a conventional bolus dose of spinal anaesthetic. Fractionating the spinal dose was reported to have haemodynamic stability with a longer duration. Here, we present five cases of high-risk elderly patients with multiple comorbidities who presented for orthopaedic surgeries and were successfully managed with fractional spinal anaesthesia.

INTRODUCTION

The elderly population presents a great challenge to anaesthesiologists because of the multiple associated comorbidities, frailty and decreased cognitive reserve with a greater risk for perioperative adverse outcomes. Spinal anaesthesia (SA) is the most used anaesthetic technique for lower limb surgeries. The precipitous hypotension from sympathectomy with a conventional bolus dose for SA is poorly tolerated by frail elderly. Fractionating the conventional spinal dose has recently been reported to have better haemodynamic stability in SA.[1,2] We hypothesised that fractionating the spinal dose will offer better haemodynamic stability in high-risk cases. Here, we present the successful anaesthetic management of five elderly high-risk patients of American Society of Anesthesiologists (ASA) physical status III-IV who presented for orthopaedic lower limb surgeries by fractional spinal anaesthesia (FSA) from July to September 2022 after taking informed consent from them for publication of the case reports.

CASE DESCRIPTION

Case 1

A 75-year-old female, who was hypertensive, diabetic, with parkinsonism and on irregular medication, presented with a fracture neck of the femur following a fall due to syncope and chest pain. On evaluation, her electrocardiogram (ECG) showed non-ST elevation myocardial infarction (NSTEMI). So, she was heparinised and started on dual antiplatelets. Other investigations revealed a deranged renal function and anaemia. Her echocardiography showed concentric left ventricular (LV) hypertrophy and an ejection fraction (EF) of 50%. Cardiology and nephrology evaluation was done. Her hypertension and diabetes were controlled and stabilised on medications, and she was scheduled for hemiarthroplasty 1 week later. We managed this elderly with FSA. The perioperative period was uneventful, without any fresh ECG changes or troponin rise.

Case 2

A 90-year-old man with femur trochanteric fracture who was a known comorbidities. This had a history of aortic stenosis with biprosthetic valve replacement, with grade 2 dyspnoea on exertion (DOE). His pulse rate (PR) was 78 beats/min with atrial fibrillation (AF), and ECG showed AF with no ST–T changes. Echocardiography revealed biprosthetic valve with a maximum atrioventricular AV pressure gradient of 34 mmHg (average 20 mmHg), concentric LV hypertrophy with LV diastolic dysfunction, pulmonary arterial hypertension (PAH) grade 2 and mild mitral regurgitation (MR).

Case 3

A 70-year-old man with a fracture neck of the femur was scheduled for hemiarthroplasty. He was a known case of valvular heart disease with grade 2 DOE and was hypertensive on irregular medications. His baseline PR was 89 beats/min, blood pressure (BP) was 200/120 mmHg and haemoglobin was 9 g/dl. Echocardiography showed rheumatic heart disease – moderate mitral stenosis (valve area 1 cm²) with moderate PAH and MR with the dilated left atrium. The patient was given analgesia with a femoral nerve block, paracetamol 1 g intravenous (IV) infusion, sedation with midazolam 0.5 mg IV, and dexmedetomidine 0.5 μg/kg IV over 15 min. The patient was stabilised and taken up for surgery after a few hours.

Case 4

An 80-year-old man, a chronic smoker, hypertensive and with coronary artery disease, presented with a femur fracture. He also had a cerebrovascular accident 1 month before and was now showing residual hemiparesis on the left side. His PR was 70 beats/min, BP was 180/100 mmHg and bilateral basal crackles in the chest. ECG showed right bundle branch block and T inversion in V1–V6. Echocardiography revealed a patent foramen ovale with left-right L–R shunt, moderate LV dysfunction, PAH, and dilated inferior vena cava. Serum troponin I was positive. After the risk–benefit analysis of regional and general anaesthesia and discussion with relatives, the decision to proceed with FSA was taken.

Case 5

A 78-year-old man, hypertensive with grade 2 DOE and asthmatic on regular medication, was scheduled for femur fracture fixation. He had an active respiratory infection with bilateral bronchospasm and room air oxygen saturation of 86%. His BP was 190/100 mmHg, and PR was 126 beats/min, and he had a systolic murmur at the aortic area. Echocardiography showed aortic sclerosis with a valve area of 1 cm², global LV dysfunction with an EF of 50% and pulmonary artery pressure of 42 mm H₂O. The D-dimer level was not elevated. The patient was optimised with nebulisation and supplemental oxygen.

All these high-risk cases were managed by FSA using 0.5% hyperbaric bupivacaine (7.5–10 mg) with 20 μg of fentanyl. The spinal drug was administered in fractions (two-thirds of the initial drug volume and one-third after 90 s), except for the second case. For the second case, the drug volume was given in three fractions, each with a gap of 45 s. None of the patients had significant haemodynamic changes with FSA intraoperatively [Table 1 and Figure 1] or any untoward perioperative events.

Table 1.

Haemodynamic parameters

Time	Case 1			Case 2			Case 3			Case 4			Case 5
	HR	SBP	DBP	HR	SBP	DBP	HR	SBP	DBP	HR	SBP	DBP	HR	SBP	DBP
On arrival	84	150	90	78	140	80	89	200	120	70	180	100	126	190	100
0 min (just before spinal)	82	148	84	72	132	76	62	170	106	74	160	98	118	165	96
1 min	78	132	80	74	122	70	64	150	100	79	140	86	110	140	90
3 min	74	130	70	69	118	66	72	130	98	78	122	80	108	120	76
5 min	72	120	72	70	100	64	75	92b	60	72	118	78	109	106	66
10 min	76	118	78	97	90a	60	64	106	70	75	118	78	112	88a	70
15 min	74	114	80	86	106	64	66	118	78	80	120	74	96	100	78
20 min	80	118	82	76	110	70	70	120	80	74	122	70	99	116	80
25 min	82	110	74	74	114	70	68	118	86	78	118	68	99	118	82
30 min	80	120	72	73	110	72	70	110	80	80	118	74	96	124	88
35 min	78	120	78	75	114	68	74	118	88	82	120	80	92	120	86
40 min	76	120	70	76	118	72	72	120	90	77	126	82	90	126	90
45 min	88	124	68	78	110	70	74	126	90	72	128	88	90	130	90
50 min	82	118	70	76	110	68				73	130	86	94	128	84
55 min	78	120	66	77	118	70				76	128	90	90	136	88
60 min	79	124	70	80	116	66				70	130	90
65 min				78	128	72
70 min				76	120	74
75 min				78	120	70

DBP=diastolic blood pressure in mmHg, HR=heart rate in beats per minute, IV=intravenous, SBP=systolic blood pressure in mmHg. ^aResponded to phenylephrine IV single bolus dose of 50 μg. ^bRequired two bolus doses of phenylephrine 50 μg

Figure 1.

Intraoperative mean arterial pressure changes in the five cases

DISCUSSION

SA has undergone many modifications to eliminate the associated undesirable haemodynamic adverse effects and to make it more clinically useful even in high-risk patients. The addition of opioids like fentanyl, low-volume preferential unilateral blocks and epidural volume expansion are some of these modifications tried. The latest in the list is FSA, a technique of administering the spinal drug in two or more fractions with a time gap of 45–90 s between the fractions.

Bolus dose with conventional SA causes profound hypotension with an average incidence of 15%–33%, which increases with age, crossing 75% in those older than 50[3] and remains high even with low-dose SA in the elderly.[4] The decreased cardiorespiratory reserve with high resting sympathetic and baroreceptor activity and multiple comorbidities in older adults increases perioperative morbidity and mortality. Fractionating the bolus dose in SA is reported to have better haemodynamic stability and denser blockade.[1,2]

As elderly high-risk patients with cardiac dysfunction depend on LV end-diastolic volume to maintain their stroke volume and cardiac output, the consequences of sympathectomy with SA will be exaggerated. Diastolic dysfunction and reduced baseline cardiac output with the inability to increase the output after SA are the basis of exaggerated post-spinal hypotension in older adults.[5]

Fractionated dosing was reported to cause longer duration with less hypotension and bradycardia and fewer perioperative complications than bolus dose SA.[2] The injection rate has a significant effect on haemodynamics, and a slower rate of spinal drug administration is reported to reduce significant hypotension.[6,7] The exact mechanism of haemodynamic stability with FSA has yet to be clearly discovered. With fractionating the dosing, a lower initial volume of drug spreads in a lesser area, causing vasodilatation and lesser hypotension as sympathectomy is not rapid as with conventional bolus dosing. The subsequent fractions of the drug act on the same blocked area; therefore, there is no further vasodilatation. The longer duration could be due to the action of a second fractional drug dose on the same blocked area. Low fall incidence in mean arterial pressure requiring vasopressors and prolongation of analgesia were our main observations, like in previous reports.[1,7]

CONCLUSION

Fractionating the bolus dose in SA would result in better haemodynamic stability in elderly high-risk patients.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms from all the patients being reported in this case series. In the form, patients has given his/her consent for clinical information to be reported in the journal. Patients understands that his/her name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.