Spinal Anesthesia for Cesarean Section

Abstract

Of a series of 1,141 patients who received ephedrine prophylactically, 46% had prepartum falls in blood pressure exceeding 20% of the preanesthetic level, and in more than half of the women the systolic pressure fell below 100 mm. Hg.No correlation was found between the incidence of hypotension and the level of sensory analgesia. In a comparable group of 64 patients methoxamine hydrochloride was found to be more effective as a prophylactic and therapeutic agent than ephedrine. However, there was also a significantly greater incidence of hypertension with methoxamine. It was found that spinal anesthesia did not impair the effectiveness of ventilation as measured by arterial blood pCO2 provided small doses of the agent were used and blood pressure was maintained.MOST OBSEBVEES " agree that the hypoten¬ sion associated with spinal anesthesia for cesarean section is a problem and hypoventilation a potential hazard. However, few physiological studies have been done, and little information is available in the literature dealing with the effects of this technique on the circulation 5 7 and respira¬ tion during abdominal deliveries. In order that the cardiovascular effects might be investigated clini¬ cally, the anesthetic records of patients undergoing cesarean section during an 8%-year period (1952)(1953)(1954)(1955)(1956)(1957)(1958)(1959)(1960) at the Sloane Hospital for Women were studied in detail. The effects on ventilation were studied by means of arterial-blood gas determina¬ tions in 15 patients. Method and MaterialCardiovascular Studies.-The charts of 1,633 con¬ secutive patients who underwent spinal anesthesia for elective (40%) or emergency cesarean section during the period of February, 1952, through July, 1960, were studied. As a rule, spinal anesthesia was avoided in patients with chronic anemia and known or suspected hypovolemia due to hemorrhage. The majority of the women (89%) were in good health, with normal physical and laboratory findings. The remainder presented complications which did not contraindícate spinal anesthesia-notably diabetes, bronchial asthma, toxemia, and upper respiratory infection. Almost all the anesthetics were admin¬ istered and supervised by resident physician anes¬ thesiologists. The anesthetic charts of all patients were carefully examined in order that the incidence and magnitude of pre-and postpartum changes in pulses and blood pressure might be studied. The changes observed in these parameters were cor¬ related with the prophylactic and therapeutic use of vasopressors, dose of local anesthetic, level of anesthesia, use of oxytocic agents, and the pres¬ ence of toxemia.The technique used in the administration of the anesthetic was as follows: The patients were usual¬ ly premedicated with 50 mg. of meperidine hydro¬ chloride and 0.4 mg. of scopolamine, intramuscular¬ ly, Vh hours before induction of anesthesia. As a prophylactic vasopressor, 50 mg. of ephedrine was given intramuscularly to 72% of the patients about 10 minutes before the lumbar puncture. Methoxa¬ niine hydroc...

Prevention and management of hypotension during spinal anaesthesia for elective Caesarean section: a survey of practice

“…Considerable work has been done on the use of vasoconstrictors in the prevention and treatment of hypotension during spinal anaesthesia. A study published in 1962 [16] showed that intramuscular ephedrine (50 mg) given 10 min before the spinal failed to prevent a 20% decrease in blood pressure in 46% of patients. Ephedrine is more conventionally given intravenously.…”

Central Neural Blockade and Caesarian: Section. Part 1: Review and Case Series.

“…Other authors (Forthman and Adriani 1957, Moya and Smith 1962, Milne and Murray Lawson 1973, Magno et al 1976, James et al 1977 noted hypotension in from 16% to 82% of patients despite institution of some or all of the forementioned prophylactic measures. It should be stressed however that these authors have used different definitions of hypotension and are not therefore comparable.…”

“…Several studies have shown the effects of CNB on maternal blood gases during CS. Moya and Smith ( 1962 ) noted dyspncea following spinal block, but reported that maternal PaC0 2 changed minimally providing hypotension did not occur. Magno et al (1976) andJ ames et al ( 1977) also demonstrated normal maternal PaC0 2 during epidural block (i.e.…”

Anaesthesia for Caesarean section in the dog and cat: A review

“…This has been demonstrated in man by Marx, Cosmi & Wollman (1969). Another form of treatment involves the judicious adminstration of vasopressors (Moya & Smith, 1962).…”