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Year : 2023 | Volume
: 24
| Issue : 1 | Page : 85-86
Morbidly obese patient for percutaneous nephrolithotomy in prone position – Feasibility of unilateral spinal anesthesia?
Teena Bansal, Mamta Jain, Anish Kumar Singh, Jatin Lal
Department of Anaesthesiology and Critical Care, Pt. B.D. Sharma University of Health Sciences, Rohtak, Haryana, India
Correspondence Address:
Dr. Teena Bansal
19/6 J Medical Campus, PGIMS, Rohtak - 124 001, Haryana
India
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/TheIAForum.TheIAForum_109_22
How to cite this article:Sir,
Morbidly obese patients have a reduced functional residual capacity and increased closing capacity, which can cause desaturation. Percutaneous nephrolithotomy (PCNL) is generally performed under general anesthesia, which further reduces functional residual capacity. Anesthetic management of morbidly obese patients for PCNL in a prone position poses a great challenge to the anesthesiologist. We hereby present a case report of a patient with a body mass index 45 kg/m2, scheduled for left PCNL in prone position, managed successfully with unilateral spinal anesthesia.
A 40-year-old female weighing 110 kg with height 5'2” was scheduled for PCNL. She had a history of snoring. She had a history of hypertension for 2 years for which she was on antihypertensives. On examination, pulse was 80/min and blood pressure was 128/76 mmHg. Respiratory and cardiovascular systems were normal. Airway evaluation revealed MPG III, short neck with restricted extension and flexion. Difficult intubation was anticipated. Relevant investigations were normal. Unilateral spinal anesthesia was planned for the procedure. In the operating room, standard monitors were attached. Intravenous access was obtained. In the left lateral position, spinal anesthesia was given with 2.2 ml of 0.5% heavy bupivacaine. Patient remained in the left lateral position for 10 min. The adequate effect was achieved up to T4 on the left side. On the right side, T12 sensory level was achieved after 10 min. Then, the surgery proceeded in prone position. The surgery lasted for 1 h. The patient remained hemodynamiccaly stable. Intraoperative and postoperative course was uneventful.
Obese patients present a challenge to safe general anesthesia because of difficult airway, impaired cardiopulmonary physiology, and increased risk of upper airway obstruction.[1] Hence, we avoided general anesthesia and chose regional anesthesia. Options available with us were spinal anesthesia and epidural anesthesia. Although epidural anesthesia provides the advantage of a graded block and less hemodynamic variations, but its disadvantages are failure or patchy block.[2] Hence, the only option left with us was spinal anesthesia. We used unilateral spinal anesthesia as the bilateral subarachnoid block is associated with a higher incidence of hemodynamic instability.
Unilateral block only affects the sensory, motor, and sympathetic functions on one side of the body and offers the advantages of a spinal block without the typical adverse side effects seen with a bilateral block.[3] There is lower incidence of hypotension and better maintenance of cardiovascular stability. Hence, it can be a valuable technique for high-risk patients.[4] In the present case, the patient remained hemodynamically stable throughout. An important factor influencing unilateral spinal anesthesia is the dose used. Dose reduction is crucial to restrict blockade to one side. We used 2.2 ml of hyperbaric bupivacaine. An injection of 5 mg (1 ml) of hyperbaric bupivacaine 0.5% provides an hour-long block to T 12, and a dose of 7.5–10 mg (1.5–2.0 ml) extends the block to T6. The baricity of the injected solution, the shape of the spinal needle, the injection speed, the patient's position during injection, and the time the patient remains in this position after injection is equally important parameters influencing unilateral spinal anesthesia.[3] Maintenance of the lateral position for a determined length of time restricts the surgical block to the side to be operated. Hence, we kept the patient in a lateral position for 10 min as the drug gets fixed in 10 min.[5]
We wish to highlight that in a morbidly obese patient posted for PCNL, unilateral spinal anesthesia provides the advantage of establishing the block on the side of surgery only. Further, it maintains hemodynamic stability and hence hemodynamic alterations are avoided.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
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