A Superior Anesthetic Technique for the Cesarean Section From a Hemodynamic Perspective.
Condition: Obstetric Anaesthesia With Cardiac Complications
Study type: Observational

Summary: 
      Cesarean section operations are increasing in rates worldwide. A proper anesthetic technique
      is required to maintain the safety of both the mother and the fetus. This study examines the
      adverse hemodynamic effects associated with general and regional anesthesia and proposes a
      superior technique from the hemodynamic perspective.

      A retrospective cohort study with a five-year study period was conducted on patients who
      underwent cesarean section with general anesthesia (GA) and regional anesthesia (RA) after
      obtaining ethical committee approval. Data (hypotension, bradycardia, and blood loss) was
      collected from hospital information system records of the patients who underwent cesarean
      section from January 2015 to December 2019. The significance of the variables was determined
      using the Chi-square test.

      A total of 2500 patients were studied. 1379 patients underwent cesarean section with RA
      meanwhile 1121 patients with GA.
    

Detailed description: 
      Cesarean section Over the past few decades, cesarean section (CS) rates have been increasing
      tremendously; it is the most called for surgery in the obstetric department, for instance; in
      the US, there was an increase of CS by 14% from 1998 to 2001 with a 53% increase in elective
      primary CS rates and a 13% increase in medically advised primary CS rates (Alnour et al.,
      2015). The term primary CS is used when the operation is done for the first time on a
      pregnant patient (Saha and Chowdhury, 2011). This increase in CS rates can be explained by
      the increased demand for the comfort aspect during labor and the lifesaving properties of
      this operation in certain conditions for both the mother and the baby (Chen et al., 2019;
      Tadevosyan et al., 2019). A superior anesthetic method should ease surgical discomfort,
      decrease postoperative adverse effects, and should have excellent intraoperative analgesia
      (Alnour et al., 2015; Chen et al., 2019). An anesthetic is used to alleviate the pain of CS
      operation using either general (GA) or regional (RA) (spinal (SA) and epidural (EA))
      anesthetics; sometimes, they can be used together (Alnour et al., 2015).

      Pregnancy-induced hypotension The physiological changes associated with pregnancy and
      aortocaval compression or supine hypotension syndrome are the primary cause of hypotension
      during pregnancy (Mavridou et al., 2013). Aortocaval compression associated with natural
      pregnancy decreases cardiac output (CO) and venous return (VR). It starts at 20 weeks of
      gestation when the patient is lying flat in the supine position. Blood flow from the lower
      extremities will be disrupted and delayed from reaching the central circulation and the
      maternal heart; this happens due to the compression force applied by the uterus on the
      inferior vena cava and the abdominal aorta. This could restrain blood flow to the uterus,
      increases the risk of morbidity and mortality for both the mother and the fetus. Therefore,
      choosing a proper anesthetic technique that will not cause further hypotension during the
      process of CS is important (Mavridou et al., 2013; Alnour et al., 2015; Šklebar et al.,
      2019).

      Anesthesia-induced hypotension There are two definitions of anesthesia-induced hypotension
      based on studies. It is a decrease to 80% from the baseline blood pressure value or a
      decrease of systolic arterial pressure (SAP) to <100 mm Hg. A report led in the UK in 1999
      found that most expert obstetric anesthetists utilize a hypotension limit of either 100 or 90
      mm Hg of SAP (Šklebar et al., 2019).

      General anesthesia GA is either inhaled or injected, causing a state of unconsciousness
      carefully controlled. It is clinically useful due to its ability to induct rapidly, therefore
      useful in emergency situations. GA drugs can cross the placenta affecting the fetus.
      Furthermore, it was commonly believed that it could cause birth asphyxia. GA-induced
      hypotension was noted as 28% in participants in one study, with systolic and diastolic BP not
      notably contrasting with the SA group; however, it was more hemodynamically stable and had a
      minor impact on Apgar score along with umbilical cord blood gas. ICU admissions can happen
      due to hypotension in GA but less than SA (Alnour et al., 2015; Chen et al., 2019).

      Regional anesthesia SA is given for a local anesthetic effect lasting for 2-3 hours; it is
      widely used. However, rejection by patients for this method is due to anxiety, tension, fear
      of visualizing the operating room environment, and the thought of being paralyzed. SA-induced
      hypotension was a research subject for more than 50 years (Alnour et al., 2015; Chen et al.,
      2019; Šklebar et al., 2019). The decrease in systemic vascular resistance (SVR), which is
      caused by loss of sympathetic tone in SA reduces CO and SVR. This effect will be compounded
      by fall in BP due to supine hypotension syndrome (Mavridou et al., 2013). The hypotension
      rate in SA significantly fluctuates between 7.4% and 74.1%, and in another study, 64% - 100%
      (Nikooseresht et al., 2016; Šklebar et al., 2019). Hypotension was noted as 48% of
      participants having CS under SA in a study in Libya (Alnour et al., 2015). Interestingly, it
      was reported by one of the studies that SA increased CO by 13%, with no significant changes
      observed in total peripheral resistance (TPR) or mean arterial pressure (MAP) (Ram et al.,
      2017). Hypotension was also seen in participants undergoing CS with techniques where both SA
      and EA were used together. (Chen et al., 2019). Prolonged SA-induced hypotension accompanied
      by decreased SAP can inadequately affect fetal circulation leading to fetal acidosis and
      hypoxia (Alnour et al., 2015; Šklebar et al., 2019).

      There are no studies done to compare GA and RA specifically in terms of the hemodynamic
      perspective alone (Alnour et al., 2015; Šklebar et al., 2019). Therefore, the present study
      aimed to find a superior anesthetic technique from a hemodynamic standpoint and proposed a
      better technique for managing hemodynamic instabilities of pregnant patients undergoing CS.

      Aim of this study To examine and find a better technique of anesthesia for the cesarean
      section from a hemodynamic perspective.

      Specific objectives

        -  To study adverse hemodynamic effects associated with general versus regional anesthetic
           techniques for cesarean section.

        -  To propose a superior anesthetic technique from the hemodynamic perspective for cesarean
           section.

      Methodology Setting and design A five-year retrospective cohort study on patients who
      underwent CS from 1st January 2015 to 31st December 2019 at Sultan Qaboos University Hospital
      (SQUH) in the Department of Anesthesia and Intensive care, after obtaining ethical approval
      from the Medical Research committee at SQUH in July 2020 (MREC #2178). The "TrakCare"
      hospital information system was used to acquire patients' demographic data.

      Patients The inclusion criteria of this study were all the patients that underwent CS in SQUH
      during the study period, and the exclusion criteria were missing data. The sample size of
      this study included all the patients who underwent CS in this study period, as there were no
      prior similar studies to calculate the sample size from. A total of 2500 patients were
      included and coded for identity. This study was not based on any previous studies. Therefore,
      the population was regarded as all of the patients included in the study period.

      Data collection The data was obtained from the hospital information system "TrakCare." Data
      like age, the urgency of surgery, and the type of anesthesia were all recorded before each
      surgery, along with the ASA physical status classification system grade. Intraoperative data
      included heart rate (HR) measured as beats per minute (bpm) and blood pressure (BP) measured
      as (mm Hg) were obtained from the anesthesia records in the attached Electronic Patient
      Record (EPR) documents. Blood loss measured in liters (L) and APGAR scores of newborns were
      also obtained from the surgery notes and clinical notes along with the use of vasopressor
      intraoperatively. Postoperative anesthesia-related complications were recorded along with the
      postoperative length of stay (Days) and the mortality of the mother and the baby.

      Data analysis Data was collected, and the patient's identity was coded. Individual data
      coding was done and analyzed using Statistical Package for the Social sciences (SPSS)
      software (version23). Descriptive statistics were used to present the data. The Chi-Square
      test was used to determine the association between different variables under investigation
      with a p-value of <0.05 considered to be statistically significant. Continuous variables were
      suitably analyzed using means+/- SD. Missing data was ignored if the percentage of the
      missing data was less than 10%. The graphical representation tools of SPSS software such as
      bar charts, pie charts, and cross-tabulation were used to describe the analyzed data and
      present the categorized and uncategorized variables.
    

Intervention name(s): General Anesthesia; Regional Anesthesia
Intervention type(s): Procedure; Procedure
Intervention description(s): General anesthesia with intubation, ventilation, intravenous and inhalational anesthetics, opioids and muscle paralysis; Spinal Anesthesia, Epidural Anesthesia
Intervention MeSH terms: Anesthetics
Observational model: Cohort
Time perspective: Retrospective
Sampling method: Non-Probability Sample
Study population: 
        All the patients who underwent Cesarean section under either type of Anesthesia, electively
        or in an emergency situation, with different indications, were included in the study.
      
Keywords: cesarean section; hemodynamics; general anesthesia; regional anesthesia; intraoperative complications; APGAR Score