Background: Spinal anesthesia in parturients that undergo cesarean section is a method of choice, but some patients complain about shortness of breath after surgery. This might be due to spinal block may have effect on huff cough strength resulting in the difficulty to expel the mucus from the lungs. The Mini-Wright Peak Flow Meter, the surrogate device of huff cough strength, is a bedside equipment used to assess exhalation force by its peak expiratory flow rate (PEFR). As a result, the investigators would like to know if the spinal block affected the parturient huff cough strength.

Objective: To evaluate the spinal anesthesia during cesarean section effect on the parturient huff cough strength and to find the factors that influence the difference of PEFR beside the spinal block.

Materials and Methods: The PEFR was recorded three times in 161 healthy term pregnant women at 38 to 42 weeks of gestational age that were scheduled for elective cesarean section, at preoperative, immediate after spinal block, and before discharge from the recovery room. The measurement was performed in all parturients with 15 degree left lateral tilt position and the highest PEFR achieved in three successive attempts. The spinal anesthesia with 10.75 to 11 mg of 0.5% hyperbaric bupivacaine and 0.15 to 0.2 mg morphine was performed under the standard anesthetic care.

Results: One hundred sixty-one patients successfully completed the present study. The PEFR appeared to decrease significantly after spinal block from 285.53±55.21 L/minute to 238.70±49.69 L/minute (p<0.001) and seemed to sustain till the time of discharge from the recovery room at 235.40±47.29 L/minute (p=0.493). These implied that though the patients fulfilled the discharge from recovery criteria, the level of sensory blockade was not yet improved. Interestingly, these values were comparable and showed no correlation with age, BMI, and solid sensory blockade.

Conclusion: Spinal anesthesia might affect huff cough strength in parturients that underwent elective cesarean section as evidenced by the decrease of PEFR even at the time of discharge from the recovery room.

Keywords: Bupivacaine; Cesarean section; Huff cough strength; Parturient; Peak expiratory flow rate; Spinal anesthesia

DOI: 10.35755/jmedassocthai.2022.10.12780

Received 25 October 2021 | Revised 16 June 2022 | Accepted 16 June 2022