A Comparative Study of Supine Position and the Head Elevated Position on the Level of Sensory Block After Spinal Anesthesia in Morbidly Obese Parturient Undergoing Elective Cesarean Delivery

The sniffing position defined as neck flexion with upper cervical extension, is traditionally recommended for general anesthesia induction, as it improves laryngoscopic views. However, the head elevation beyond the sniffing position, also known as ramped position or head elevated laryngoscopy position, usually achieved by specially designed pillows such as the Oxford head elevating laryngoscopy pillow (Alma Medical,Oxford, UK) or the Troop® elevation pillow (Mercury Medical, Clearwater, FL, USA)has been shown to not only increase respiratory reserve but also to improve laryngeal views in patients undergoing bariatric surgery. Additionally it helps in pre-oxygenating the patient more efficiently by keeping the airway patent and provides easier bag-mask ventilation.

It may also benefit the term parturient in a similar way by improving functional residual capacity (FRC), ventilation and comfort. However, this positon may affect the cephalad spread of the intrathecal local anesthetic.

Two earlier studies looked at the intrathecal local anesthetic spread in obstetric patients when placed in the head elevated laryngoscopy position, and both suggested poor cephalad spread, with patients requiring higher supplementation.

However, both studies excluded morbidly obese patients. The Investigators hypothesized that in obese parturients with BMI more than or equal 40, higher intra-abdominal pressures and possibly lower CSF volumes will counteract the poor cephalad spread associated with this position. The aim of this study is to determine the effect of a ramped position on intrathecal local anesthetic spread in the morbidly obese term parturients with BMI more than or equal 40 undergoing elective Cesarean delivery(CD).

Study Overview

• Status: Completed
• Conditions: High BMI
• Intervention / Treatment: Other: head elevated laryngoscopy position by Oxford pillow

• Study Type: Interventional
• Enrollment (Actual): 90
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Qatar
  • Doha, Qatar
    • Hamad Medical Corporation

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age 18yrs of age or more
• BMI 40 or more and more than or equal 37 weeks of gestation
• elective CD
• consented for neuraxial anesthesia
• singleton fetus
• ASA class 3 (no co-morbidities except morbid obesity, gestational diabetes, and gestational hypothyroidism)

Exclusion Criteria:

• Age <18 years
• BMI less than 39.9 and <37 weeks of gestation
• parturient preference for general anesthesia or contraindication to neuraxial anesthesia
• Women with comorbidities other than obesity, gestational diabetes or gestational hypothyroidism.
• women in active labor (>3 cm dilated with regular uterine contractions)
• emergency CD
• Possible uterine over-distension or under-distension (e.g. polyhydramnios, estimated fetal weight >4 kg by ultrasound scan, or oligohydramnios or concern for fetal IUGR)
• maternal height <150 cm or >180 cm.
• Patients for which more than 2 minutes is taken in positioning after anesthesia induction (Time 0).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: HEAD ELEVATING LARYNGOSCOPY PILLOW; the head elevation beyond the sniffing position, also known as ramped position or head elevated laryngoscopy position, usually achieved by specially designed pillows such as the Oxford head elevating laryngoscopy pillow (Alma Medical, Oxford, UK) or the Troop® elevation pillow (Mercury Medical, Clearwater, FL, USA)	Other: head elevated laryngoscopy position by Oxford pillow; ramped position, also known as head elevated laryngoscopy position,
No Intervention: Standard pillow group

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
The sensory level (loss of cold and pin prick sensation) at 15 min after the intrathecal administration of the medication in the parturient	From date of randomization until the date of first documented progression, assessed up to 48 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of inadequate block level at 15 min and need for epidural supplements	Secondary Outcomes: I. Incidence of inadequate block level at 15 min II. The need for epidural supplementation. III. Dosage of epidural local anesthetics to achieve adequate block level following the spinal anesthetic. IV. The need and dosage of iv opioids for intraoperative supplemental analgesia V. The incidence of pain throughout the procedure (by the use of NRS). VI. The use and dosage of vasopressor. VII. The rate of conversion to general anesthesia. VIII. Maternal satisfaction with the position. IX. Neonatal outcomes (Birth weight in kilograms, APGAR scores, umbilical cord gases and lactate)	From date of randomization until the date of first documented progression, assessed up to 48 months

Collaborators and Investigators

• Sponsor: Hamad Medical Corporation

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2023
• Primary Completion (Actual): July 11, 2024
• Study Completion (Actual): December 10, 2024

Study Registration Dates

• First Submitted: February 23, 2025
• First Submitted That Met QC Criteria: March 16, 2025
• First Posted (Actual): March 25, 2025

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: March 16, 2025
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Other Study ID Numbers: MRC-01-21-032

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No